# Update of the E CO WA S Revis ed Mas ter P lan

# for the gener ation and tr ansm iss ion

# of elec tr ic al ener gy

## Final Report Volume 2 : Optimal development plan and analysis

## of transmission network performance and stability

_EEccoonnoommiicc CCoommmmuunniittyy CCoommmmuunnaauuttéé EEccoonnoommiiqquuee_ _**OOff WWeesstt AAffrriiccaann SSttaatteess** DDeess EEttaattss ddee ll’’AAffrriiqquuee ddee ll’’OOuueesstt_ _**General Secretariat / Secrétariat Général**_

### WEST AFRICAN POWER POOL (WAPP)

#### October 2011

* * *

OF ELECTRICAL ENERGY
Final Report Volume 2: Optimal development plan and
analysis of transmission network performance and stability

TABLE OF CONTENTS

1. INTRODUCTION ..... 5

1.1. Context ..... 5

1.2. Structure of Volume 2 of the Final Report ..... 6

2. ECONOMIC ANALYSIS ..... 7

2.1. General methodology ..... 7
2.1.1. Methodological principles ..... 7
2.1.2. Techniques of simulation and optimization ..... 8
2.1.3. Taking into account the impact of the hydrological conditions ..... 9
2.1.4. Current operational difficulties in the electrical networks of the WAPP ..... 9

2.2. Data ..... 10
2.2.1. General data ..... 10
2.2.2. Fuels ..... 11
2.2.3. Load forecast ..... 18
2.2.4. Generation data ..... 33
2.2.5. Transmission data ..... 56
2.2.6. Presentation of the results .....

written approval
to third parties is forbidden without prior
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

2.5.1. Implemented production means ..... 68
2.5.2. National production projects ..... 70
2.5.3. Production projects supported by regional entities ..... 102
2.5.4. Great regional production projects ..... 103
2.5.5. Regional transmission projects ..... 107

2.6. Comparison of the scenarios ..... 113

2.7. Studies of sensitivity ..... 114
2.7.1. Scenario 3 ..... 114
2.7.2. Alternative with delay of the transmission projects ..... 114
2.7.3. Alternative with a lower load growth ..... 115
2.7.4. Renewable alternative ..... 116
2.7.5. Alternative low fuels cost ..... 122
2.7.6. Alternative high fuels cost ..... 123
2.7.7. Alternative with low actualization rate ..... 124
2.7.8. Alternative with high actualization rate ..... 12

written approval
to third parties is forbidden without prior
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

3.4.9. Dynamic security assessment: Maximum transfer capacities .....214

3.5. Operation of the system and control centers .....235
3.5.1. Policy 1: Load frequency control .....235
3.5.2. Policy 2: Interchange scheduling and accounting between control areas..236
3.5.3. Policy 3: Operational security .....237
3.5.4. Policy 5: Emergency procedures.....238

3.6. Conclusions and recommendations .....239
3.6.1. Model construction and scenarios investigated .....239
3.6.2. Conclusions of static studies .....240
3.6.3. Conclusions of dynamic studies .....241
3.6.4. Critical conclusions .....245
3.6.5. Impact on the results of the economic study .....246

4. APPENDIX: STATIC STUDIES: SHORT-CIRCUIT AN

written approval
to third parties is forbidden without prior
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

* * *

1. INTRODUCTION

The present report constitutes the Volume 2 of the Final Report of the „Update of the
ECOWAS Revised Master Plan for the generation and transmission of electrical
energy‟.

The Final Report includes the following volumes:

Volume 1: Study Data

Volume 2: Optimal development plan and analysis of transmission network
performance and stability

Volume 3: Investment program development and priority project implementation
strategy

Volume 4: Executive summary

1.1. Context

The system of the West African Power Pool (WAPP), a specialized institution of
ECOWAS, constitutes the institutional framework of the regional electric system.
The WAPP‟s strategic objective is based on a dynamic vision of the integration of
the operation of the national electrical networks in a unified regional market. This
unified regional market has to ensure in the medium and long term an optimal and
reliable electricity supply at an accessible cost for the population of the different
Member States.

The objective is to aim at the common economic good, thanks to a long-term cooperation in the energy sector and with the development of transborder exchanges of
electricity.

This update of the master plan aims at integrating the ongoing developments in a
medium and long term strategy of expansion of the regional infrastructures of
production and transport, while keeping it coherent with the WAPP‟s vision.

The purpose of the present study is to update the regional plan of production and
transport for submission to the General Secretary of the WAPP and the whole of the
electric sectors of the Member States.

third parties is forbidden without prior written approval
to
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

1.2. Structure of Volume 2 of the Final Report

This Volume 2 of the Final Report describes the second phase of the study dedicated
to the optimal development plan and to the analysis of transmission network
performance and stability.

This report includes the following parts:

Chapter 2: presents the methodology, the data and the results of the economic
study. The purpose of this study is to calculate a first optimal
investment plan of production and transport and to draw up a first list
of priority projects,

Chapter 3: presents the results of the network performance calculations and the
stability analysis of the interconnected system. This part highlights the
modifications to bring to the first list of priority projects for technical
reasons.

The detailed data gathered during the data collection phase were presented in the
first intermediate report of the study published in April 2011.

These data were discussed with the representatives of the WAPP and the
representatives of the ministries and the electrical companies of the 14 Member
States, during the workshop organized in Cotonou on May 5th, 6th and 7th 2011.

Please note that in this report the syntheses of the data used for the economic study
and the performance and stability studies of the network are included respectively in
chapters 2 and 3.

These syntheses take into account the comments and modifications which were
provided by the Member States and the WAPP during the presentation of the first
intermediate report, during the first presentation of the Optimal development plan
which took place on July 15th and 16th 2011 in Cotonou and during the meeting
th
held in Cotonou on August.27 2011 for presenting the priority list of investments.

The list of regional priority interconnection projects presented in this report will be
re-examined in the following phase of the study to take into account the additional
impacts of the environmental, financial and institutional constraints.

third parties is forbidden without prior written approval
to
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

2. ECONOMIC ANALYSIS

2.1. General methodology

2.1.1. Methodological principles

The objective of the economic analysis is to work out a first priority investment plan
based on technico-economic simulation of the electric systems in all the West
African countries. This priority investment plan will distinguish:

• national projects of production, projects of production supported by regional
entities (OMVS, OMVG) and regional projects of production,
regional projects of interconnection.

• regional projects of interconnection.
The list of priority investments is based, first, only on the economic analysis. Then,

The list of priority investments is based, first, only on the economic analysis. Then,
the system analysis of the power flows, will make it possible to better adapt this list
to the technical constraints of network operation.

Please note that in a later phase of the study, the environmental, financial and
institutional impacts will also be studied and the list of priority investments will be
adapted consequently.

The economic analysis detailed hereafter includes the following stages:

• Setting up a scenario proposing the evolution until 2025 of the national parks of
production as proposed in the national master plans without development of new
interconnections (scenario1);
• Setting up a scenario which proposes an optimal development of the park of

• Setting up a scenario which proposes an optimal development of the park of
production at the regional level by supposing that no limit of power transit
applies between the countries of the area. This theoretical scenario highlights the
most interesting regional production projects. The comparison between this
second scenario and the first one makes it possible to obtain the maximum profit
that can be expected from the regional production projects. (scenario 2);

The sensitivity studies carried out correspond to the setting up of the following
scenarios:

• A development scenario corresponding to the assumption that the regional
planned transport projects as well as the OMVG projects are postponed by two
years (scenario 4),
A development scenario corresponding to the realization of the scenario of low

• A development scenario corresponding to the realization of the scenario of low
growth of the electric demand (scenario 5),

third parties is forbidden without prior written approval
to
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

• A development scenario corresponding to the voluntary assumption of
investment into renewable energy so that the quota of renewable energy in the
entire installed power of the area reached the goal of 10% between now and
2020\. (scenario 6),
A development scenario corresponding to the assumption of a drop in fuel prices

• A development scenario corresponding to the assumption of a drop in fuel prices
(75 USD/bbl for crude oil) (scenario 7),
A development scenario corresponding to the assumption of a rise of fuel prices

• A development scenario corresponding to the assumption of a rise of fuel prices
(125 USD/bbl for crude oil) (scenario 8),

• A development scenario corresponding to an actualization rate of 8% (scenario
9),

• A development scenario corresponding to an actualization rate of 12% (scenario
10),
A development scenario corresponding to the assumption of a limitation of the

• A development scenario corresponding to the assumption of a limitation of the
total hydroelectric capacity that can be installed in Guinea during the study
period (scenario 11).
The costs and benefits of regional interconnection projects suggested as a priority

The costs and benefits of regional interconnection projects suggested as a priority
and added to the already decided and planned projects will also be examined by
comparing the scenarios where these projects are and are not implemented.

The economic study thus described will allow defining the first lists of the national
and regional priority investments in production. It will also make it possible to
define a first list of regional priority investments in transmission and
interconnection. It will highlight in particular the optimal capacities of the
installations (production and interconnection capacities).

As mentioned here before, the lists of national and regional priority investments
deduced from the economic analysis will be then re-examined by taking into account
the results of the technical analysis of the operation and the study of stability of the
inter connected networks. This technical analysis of the networks includes:

• Static and dynamic studies for the 2015 peak load and for two representative
situations (interconnections of the countries and limitation of the development of
the interconnections),
• Static and dynamic studies for the 2015 off-peak load and for two representative

These optimizations are based on the tool PRELE, developed by the Consultant and
especially envisaged for this purpose. The model PRELE is designed to represent in
the same modeling the production parks and the grid systems of all the countries
with their interconnections. It optimizes the operation and if necessary the
investment decisions of the system on the whole study period by minimizing the
actualized total costs of the system and by respecting the imposed planning criteria.
Moreover it takes into account real constraints such as the construction delays of the
various power plants, hydrology (dry and wet years), the availabilities in terms of
fuel per country (Gas, HFO, Diesel, LCO…), etc

• Static and dynamic studies for the 2015 off-peak load and for two representative
situations (interconnections of the countries and limitation of the development of
the interconnections),
Static studies for the peak load in 2020 and 2025.

2.1.2. Techniques of simulation and optimization

The technical analysis of the networks will permit to release the possible
modifications to bring to the priority investments list to ensure the feasibility of the
operation of the electrical networks.

• Static studies for the peak load in 2020 and 2025.
The technical analysis of the networks will permit to release the possible

third parties is forbidden without prior written approval
to
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

The outputs of this modeling thus indicate the optimum between the use of the
existing power plants (utilization periods, costs of maintenance and fuel) and the
development of new hydraulic, thermal and renewable plants (types of power plants
and capacities by country, years of commissioning). They propose moreover
optimum flows of capacity between the countries.

The development plan optimized using the tool PRELE takes into account the types
of units necessary to cover the demand while respecting various constraints such as
the variability of the load diagram (peak and off-peak load), the variability of
primary energies (dry year, wet year, dry season, wet season, availability of gas,…),
but also the constraints related to the units operation (technical minimum, must runs,
etc). In particular, it takes account of the minimum of thermal plants to install to face
the driest years. It also takes into account the necessary construction delays, which
supports the thermal units during the first years.

2.1.3. Taking into account the impact of the hydrological
conditions

It is not useful to develop in the sensitivity study one or more additional scenarios
corresponding to hydrological conditions of dry year. Indeed, the risk due to the
uncertainty of the hydrological conditions of the hydroelectric projects is already
taken into account directly while modeling in PRELE. In this modeling one indeed
introduced various states of the system related to situations of dry years, of years of
normal rainfall, dry season, wet season and combinations of these parameters. Each
state is characterized by its probability of occurrence. Productible energies by each
hydroelectric project in these various states take account of the statistics of
hydrology gathered during the data collection. The optimization of the electric
system takes directly into account the impact of the various hydrological conditions
with their probability of occurrence.

2.1.4. Current operational difficulties in the electrical networks of
the WAPP

The data collection phase in the various Member States clarified many current
operational difficulties in the electrical networks of the Member States.

These difficulties are due to various causes such as the lack of available fuel related
to financing problems (Senegal) and the run-down state and the lack of maintenance
of the existing equipment (in the majority of the countries). As a consequence, a
significant part of the installed capacity in production units in the area is currently
unavailable. This raises the question of the `unserved demand. Technical measures  must be implemented to gradually reduce this unserved demand, such as the  implementation of appropriate maintenance policies, the accelerated rehabilitation of  some existing production units, etc. It is supposed in the source data that`the
unserved demand' will be gradually eliminated after a 6 years period. Even if this
assumption can appear optimistic in the current context of the electric sector in the
area, it was however kept because the long-term tendencies that one seeks in this
study must remain coherent with the natural growth of the load and the length of the
study does not exceed 15 years. Moreover, the sensitivity study on the load growth
must make permit to evaluate the impact of lower load levels in the future.

third parties is forbidden without prior written approval
to
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

Another difficulty which arises in certain countries results from „non technical‟
losses (frauds) and the non-payment of the bills. To solve this last problem, certain
countries systematically introduced prepaid tariffs.

With regard to the exploitation of the current interconnections, it is necessary to
announce the following problems:

• Currently, in the group of interconnected countries composed of Ivory Coast,
Burkina Faso, Ghana, Togo and Benin the short-term power reserve in operation
is definitely insufficient and even nearly non-existent because of the under
equipment of the various countries. Only Ghana can align a certain operational
reserve thanks to the units of Akosombo. As a consequence, in the event of an
incident in a country, the interconnections cannot fully ensure their role of help
due to the lack of operational reserve in the neighboring countries. It is thus
urgent to implement in the very short term in these countries adequate units
and/or to release the required funds to develop a reserve at least equal to the
largest production unit of these countries (in particular in Ivory Coast and in
Burkina Faso).

There is currently already a risk of slow oscillations between the parks of the

• Currently, the interconnection between Benin and Nigeria remains open because
of adjustment problems of power-frequency in Nigeria. Nigeria announced
measures which should make it possible to stabilize the network of the country in
the near future. Meanwhile, Benin has to modify daily its exploitation scheme
and the localization of the opening points of the Ghana-Togo-Benin block with
the part of the Beninese network that remains connected to the Nigerian network.
This is carried out in order to permanently keep an importation of 150 MW from
Nigeria towards Benin (importation contract). In the near future, Nigeria must
thus succeed in taking the appropriate measures and making the required
investments to close this Benin-Nigeria interconnection.

2.2. Data

This chapter describes the data used within the framework of the economic study.
These data relate to the fuel (cost and availability), the load forecast and the
production and transmission projects.

2.2.1. General data

• 1€=650FCFA

• 1€ =1.35 US$
1€=650FCFA

The foreign exchange rates considered in the study are:

third parties is forbidden without prior written approval
to
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

2.2.2. Fuels

Currently in West Africa, a broad variety of fuels are used such as, diesel oil (DDO),
light crude oil (LCO), heavy fuel oil (HFO), natural gas (NG) and to a lesser extent
coal. Among the planned units, apart from the hydroelectrical units, the majority of
them will use NG for the countries of zone A and HFO or DDO for the countries of
zone B. Several studies also propose the use of coal.

The natural gas used by the countries of zone A comes either from local gas
resources or from imported through the West African Gas Pipeline (WAGP). The
liquid fuels come mainly from Nigeria.

For the sake of a diversification of energy mix, of reducing the dependence to liquid
fuel and reducing the fuel cost, other fuels will be considered for the electrical
production within the framework of the master plan, in particular coal.

2.2.2.1. PRICE OF FUEL

The crude oil prices (thus also the price of its derivatives) and of natural gas are
closely dependant. Coal as a primary energy source for the electrical production, is
also related to the crude oil price. Nevertheless, the correlation between the prices of
coal and crude oil is less important than the one linking the derivatives of oil, natural
gas and crude oil.

In this study, it was agreed that the international fuel prices will be used. In this way,
opportunity costs of locally available fuel will be taken into account and it prevents
the local market of electricity of being skewed by “subsidized” fuels. In case of
power exchange between countries, it is then avoided that a country subsidizes
another country by selling electricity for a lower price than the real one (or market
price).

In this study, a great attention is paid to the relative difference between fuels prices
and not on their absolute level. For this reason, the crude oil price is considered
constant during all the study.

However, several scenarios are studied according to the standard price of crude oil.
Indeed, the crude oil price was extremely volatile during the last years with a strong
increase until August 2008, then a strong reduction until the end of 2008, followed
by a low rate of recovery. Recently, the events in the Arab world and in Japan
caused a big and rapid raise of the oil prices. As it is impossible to draw a long-term
tendency on which all the experts agree, various crude oil prices are studied:

• Low scenario: 75 USD/bbl;
Base scenario (corresponding to the current location): 100 USD/bbl;

• Base scenario (corresponding to the current location): 100 USD/bbl;
High scenario: 125 USD/bbl.

The fuel prices at the borders of an exporting country are estimated based on a
correlation study. It is thus necessary to add the prices of maritime transport to have
the coastal price and the prices of surface transport for the continental price.

• High scenario: 125 USD/bbl.
The fuel prices in West Africa are presented for two specific conditions, delivered to

third parties is forbidden without prior written approval
to
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

The transport costs are estimated based on the experience of the Consultant and the
publications of the IEA in the following way:

• The maritime liquid fuel transport costs per tanker of 30 000 tons are estimated to
5.9 USD/kton/mile;
The maritime transport costs of coal between South Africa or Colombia and West

• The maritime transport costs of coal between South Africa or Colombia and West
Africa are estimated to 20 USD/ton for a ship of 40 000 tons;
The terrestrial transport costs of liquid fuel by tanker are estimated to

• The terrestrial transport costs of liquid fuel by tanker are estimated to
0.11USD/ton/km;
Regarding the cost of transport of natural gas, three different prices are to be

• Regarding the cost of transport of natural gas, three different prices are to be
considered according to the source:
-WAGP (WAGP): 2 USD/MMBTU;

-WAGP (WAGP): 2 USD/MMBTU;
-Native gas: about 0.1 USD/MMBTU;

-Native gas: about 0.1 USD/MMBTU;
-LNG: Liquefaction: 0.9 -1.3 USD/MMBTU;

-LNG: Liquefaction: 0.9 -1.3 USD/MMBTU; transport: 0.4 -1.1
USD/MMBTU; Gasification & Storage: 0.3 - 0.5 USD/MMBTU.
Taking into account these costs of transport and the relations rising from the

Taking into account these costs of transport and the relations rising from the
correlation study, it is possible to consider averages for coastal and continental
prices for various fuels (taxes and subsidies exempted):

COST OF LIQUID FUELS "DELIVERED TO THE COAST"
HFO - 3.5% DDO

|  | HFO-3.5% |  | DDO |  | LCO |  |
| --- | --- | --- | --- | --- | --- | --- |
| OPEC\[USD/bbl\] | \[USD/bbl\] | \[USD/GJ\] | \[USD/bbl\] | \[USD/GJ\] | \[USD/bbl\] | \[USD/GJ\] |
| 75 | 58.8 | 9.7 | 92.6 | 16.2 | 75.9 | 13.3 |
| 100 | 78.2 | 12.9 | 125.1 | 21.9 | 101.2 | 17.8 |
| 125 | 97.6 | 16.0 | 157.7 | 27.6 | 126.5 | 22.3 |

Table 1 - Price of liquid fuels – coastal

COST OF LIQUID FUELS "DELIVERED TO THE CONTINENT"
HFO - 3.5% DDO

| COST OF LIQUID FUELS"DELIVERED TO THE CONTINENT |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- |
| OPEC\[USD/bbl\] | HFO-3.5% |  | DDO |  | LCO |  |  |
| \[USD/bbl\] | \[USD/bbl\] | \[USD/GJ\] | \[USD/bbl\] | \[USD/GJ\] | \[USD/bbl\] | \[USD/GJ\] |  |
| 75 | 79.7 | 13.1 | 111.1 | 19.5 | 92.3 | 15.1 |  |
| 100 | 99.1 | 16.3 | 143.6 | 25.2 | 115.8 | 18.9 |  |
| 125 | 118.5 | 19.5 | 176.2 | 30.9 | 139.3 | 22.8 |  |

Table 2 - Price of liquid fuels – continental

COST OF NATURAL GAS "DELIVERED TO THE COAST"
WAGP Local Gas

| OPEC\[USD/bbl\] | WAGP |  | Local Gas |  | LNG |  |
| --- | --- | --- | --- | --- | --- | --- |
| \[USD/MMBTU\] | \[USD/GJ\] | \[USD/MMBTU\] | \[USD/GJ\] | \[USD/GJ\] | \[USD/MMBTU\] | \[USD/GJ\] |
| 75 | 8.6 | 8.2 | 6.7 | 6.4 | 9.4 | 8.9 |
| 100 | 10.9 | 10.3 | 8.9 | 8.5 | 11.6 | 11.0 |
| 125 | 13.1 | 12.4 | 11.2 | 10.6 | 13.8 | 13.1 |

Table 4 - Price of coal - coastal

third parties is forbidden without prior written approval
to
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

2.2.2.2. AVAILABILITY OF FUELS

2.2.2.2.1. Availability of natural gas

This chapter presents the various possibilities of natural gas supply for the different
countries of the ECOWAS. Three sources are currently possible: the Nigerian gas
transported by the West African Gas Pipeline (WAGP), the indigenous resources of
certain countries and, in the long term, the LNG.

West African Gas Pipeline

Three countries are currently served by the West African Gas Pipeline: Benin, Togo
and Ghana. This gas pipeline transporting the Nigerian gas on a distance of 678 km
is used commercially since the beginning of 2011. In March 2011, the first
compressor plant of Lagos was commissioned allowing a gas provisioning under
pressure.

In the years to come, additional investments are going to be carried out in the
compressor plants and the gas production. These investments will make it possible
to increase the quantity of gas available in the gas pipeline. The figure below shows
the expected steps.

Reserved Capacity / Markets

Figure 1 - Gas available - WAGP

Currently, only Ghana is supplied by Nigeria according to a contract of 120 MPC/D.
As founding members, Togo and Benin can also claim a supply (5 MPC/D per
country). However, technical problems in Nigeria limit the available gas and at the
beginning of 2011, only 90 MPC/D towards Ghana were available.

third parties is forbidden without prior written approval
to
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

In addition to the quantities of gas reserved to the founding members, respectively
120, 5 and 5 MPC/D for Ghana, Togo and Benin, the additional quantities will be
available for sale on an open market. The Consultant proposes to distribute the
available quantities according to the capacity of the stations of the concerned
countries: Ghana (234MPC/D + 130 MPC/D), Benin (100 MPC/D) and Togo (100
MPC/D).

This distribution is illustrated in the graph below.

Figure 2 - Distribution of WAGP gas among the founding countries

Local gas

Another source of gas considered in the master plan corresponds to the local
reserves of the producer countries. Nigeria, Ivory Coast and Ghana have offshore
reserves. Senegal has small one shore reserves.

Nigeria is by far the country which has the greatest gas reserves in West Africa. The
figure below shows the forecasts of gas production and the gas distribution by use.

third parties is forbidden without prior written approval
to
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

Figure 3 - Forecast of production and consumption of the Nigerian gas by use

Ghana recently put in production its first offshore oil field (Jubilee Field) which
produces associated gas. This associated gas will be available at the coast in the
surroundings of Domini at the end of 2011. Following the discovery of important oil
and gas layers during the last years, the oil company of Ghana, GNPC, envisages a
big raise of gas production in the years to come going from 80 MPC/D in 2011 to
300 to 500 MPC/D in 2026.

Production de gaz ghanéen - 2011 2026

Figure 4 - Production of local gas in Ghana - 2011-2026

third parties is forbidden without prior written approval
to
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

For 2011, gas production capacities in Ivory Coast are estimated to 205 Mpc/d.
Three oil fields provide this production namely: CNR (40 Mpc/d), FOCTROT (130
Mpc/d) and AFREN (35 Mpc/d). In addition, the restitutions of the Mines and
Energy seminar organized in Yamoussoukro in June 10th and 11th 2011 give a
report on 750 Billion pc of residual reserve of gas and 1500 Billion pc of proven
reserve in Ivory Coast.

In a conservative way, the consultant supposed that a quantity of 1000 billion pc
could be consumed by Ivory Coast at the horizon of the study, among which 90% by
the electric production. This estimate takes into account the need to invest in the
increase of the gas production capacity, which could be a brake for the natural gas
supply of Ivory Coast

The quantities of gas produced in Senegal are relatively marginal today and will
remain marginal in the years to come.

LNG

Certain countries such as Ghana consider in the long term a provisioning of LNG in
their energy mix.

No limitation applies to the quantities of LNG available for the African market; the
main limitation is the non-existence of infrastructures for LNG regasification. There
exists thus an important entry cost to allow a provisioning of LNG.

Between now and 2025, the commissioning of the LNG infrastructure is
nevertheless not justified from a purely economic point of view for the supply of the
power plants of the area taking into account the limited gas quantities to export on
relatively short distances.

2.2.2.2.2. Availability of coal

No important coal center is currently exploited in West Africa.

During the optimization of the production plan, a series of coal centres are regarded
as investment option in the countries where this technology is considered in the
national plans of development, namely Senegal and Niger. These two countries have
as a common point few hydroelectric and gas resources. Moreover, Niger has coal
mines.

2.2.2.2.3. Solar potential

West Africa has particularly favourable areas for the development of solar
technologies. The chart hereafter shows the potential of the countries. If it were
decided to invest in renewable technologies in West Africa, Burkina Faso, Mali and
Niger would be good candidates for CSP solar energy.

third parties is forbidden without prior written approval
to
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

Figure 5 - DNI and the latitude of the area of interest ( [www.dlr.de](http://www.dlr.de/))

2.2.2.2.4. Wind potential

The Consultant used the wind cartography software INTERFACES VORTEX
recognized internationally by the wind sector. This software makes it possible to
model the winds in various parts of the world with the objective of leading
orientation studies.

|  | Wind resources of best identified sites(see maps in appendix) |  |  |
| --- | --- | --- | --- |
| Country | Average wind speed(m/s) | Generation(MWh/an/MW) | Comment |
| Senegal | 6 | 2588 |  |
| Gambia | 6 | 2588 |  |
| Guinea-Bissau | 5 | 1717 | This generation level is usually considered to low for investment |
| Guinea | 8 | 4051 |  |
| Sierra Leone | too low | x | No feasible wind project |
| Liberia | too low | x | No feasible wind project |
| Mali | 7.2 | 3531 |  |
| Ivory Coast | 4.8 | 1565 | This generation level is usually considered to low for investment |
| Ghana | 6 | 2588 |  |
| Burkina Faso | 6.5 | 2999 |  |
| Togo | 5.8 | 2451 |  |
| Benin | 6.5 | 3006 |  |
| Nigeria | 7.8 | 3933 |  |
| Niger | 8 | 4051 |  |

Table 5 - Wind potential by country (best identified sites)

third parties is forbidden without prior written approval
to
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

2.2.3. Load forecast

The first part of the load forecast study consists in estimating, in collaboration with
the local companies of electricity, the served and not served demand. This estimate
is done based on historical data of loads, on shedding statistics and on average time
of load supply.

The second part consists in analyzing the demand forecasts, in the short and medium
term, worked out by the companies of electricity of each country and/or of the
scenarios established by independent consultants during former studies.

The third part of the demand forecast consists, based on macro-economic parameters
(GDP, Population) and existing programs of resorption of the not served demand, in
establishing three scenarios framing the probable evolution of the demand for each
country. This phase is based on a causal forecast of the electricity demand
establishing correlations between the histories of electricity demand and macroeconomic indicators. Two complementary approaches are considered:
comprehensive approach and semi-comprehensive approach. The comprehensive
approach analyzes the correlations between the national demand for a country and
global macro-economic parameters (GDP, population, rate of electrification…)
while the semi-total approach breaks up the demand into branches of industry and/or
geographical areas.

In addition, the load estimated in the various scenarios and for the various countries
is the load of the complete system including the internal consumptions and the
losses.

A base scenario of the load forecast was established. It is used as reference scenario.
In addition, a lower growth scenario is also presented and will be exploited in an
alternative of the reference scenario.

Senegal

The GDP of Senegal (at constant price) grew on average of 4% per year over the last
10 years according to the International Monetary Fund. In the future, the annual
GDP growth should reach 4.5% to 5%.

In addition, it is important to announce and take into account the efforts made by
Senegal in terms of load management. Senegal took important actions in this field
and in particular the systematic replacement of the incandescent lamps by low
energy lamps. 550 000 lamps were replaced in 2010 (profit of 9MW estimated and
confirmed by measurements). The plan in the long term considers (at the end of
2012) the replacement of 3.5 billion lamps which should lead to a load reduction of
70 MW.

These two parameters must be weighed against in order to take into account the
various types of consumers (domestic, industrial, tertiary, tourism…)

third parties is forbidden without prior written approval
to
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

Finally, the load forecast is carried out by considering two aspects:

• the load increase in the existing interconnected network (correlation study);
the connection of isolated centers and rural electrification (cfr study SNC

• the connection of isolated centers and rural electrification (cfr study SNC
Lavalin).

|  | Base scenario\[GWh\] | Low scenario\[GWh\] | Base scenario\[MW\] | Low scenario\[MW\] |
| --- | --- | --- | --- | --- |
| 2011 | 2654 | 2561 | 456 | 440 |
| 2012 | 2991 | 2845 | 510 | 485 |
| 2013 | 3147 | 2966 | 532 | 502 |
| 2014 | 3319 | 3098 | 557 | 520 |
| 2015 | 3744 | 3428 | 629 | 575 |
| 2016 | 4311 | 3879 | 724 | 651 |
| 2017 | 4536 | 4050 | 761 | 680 |
| 2018 | 4774 | 4229 | 801 | 710 |
| 2019 | 5026 | 4417 | 844 | 741 |
| 2020 | 5306 | 4623 | 891 | 776 |
| 2021 | 5624 | 4853 | 944 | 815 |
| 2022 | 5933 | 5074 | 996 | 852 |
| 2023 | 6261 | 5306 | 1051 | 891 |
| 2024 | 6611 | 5549 | 1110 | 932 |
| 2025 | 6983 | 5806 | 1172 | 975 |

Table 6 - Forecast of the consumption of the interconnected network in Senegal in agreement with the SNC Lavalin study
of 2010

The Gambia

The population growth in The Gambia is evaluated by the International Monetary
Fund to 2.6% per year. The population of The Gambia is estimated to 1.7 millions in
2011.

Between 2000 and 2005, the GDP growth of The Gambia was fluctuating a lot from
one year to the other (between -3% and +7% of annual growth according to the
International Monetary Fund). Since 2006, the GDP growth was stabilized around
5.4%, a growth which is considered constant for the future by this Fund.
In The Gambia, the load growth is limited by the availability of supply. For this

In The Gambia, the load growth is limited by the availability of supply. For this
reason, it is difficult to establish a correlation between the growth of socio-economic
parameters and the demand growth.

The revision of the forecast contains a plan of resorption of the not served demand
during 5 years. In addition, the electrification of the isolated centers is taken into
account.

third parties is forbidden without prior written approval
to
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

|  | Base scenario\[GWh\] | Low scenario\[GWh\] | Base scenario\[MW\] | Low scenario\[MW\] |
| --- | --- | --- | --- | --- |
| 2011 | 239 | 219 | 50 | 46 |
| 2012 | 337 | 268 | 61 | 49 |
| 2013 | 414 | 317 | 70 | 54 |
| 2014 | 496 | 385 | 79 | 62 |
| 2015 | 586 | 414 | 94 | 66 |
| 2016 | 747 | 455 | 119 | 73 |
| 2017 | 771 | 496 | 123 | 79 |
| 2018 | 796 | 609 | 127 | 97 |
| 2019 | 821 | 658 | 131 | 105 |
| 2020 | 847 | 703 | 135 | 112 |
| 2021 | 879 | 722 | 141 | 115 |
| 2022 | 912 | 742 | 146 | 119 |
| 2023 | 945 | 763 | 151 | 122 |
| 2024 | 980 | 784 | 157 | 125 |
| 2025 | 1.017 | 806 | 163 | 129 |

Table 7 - Load forecast in The Gambia

Guinea Bissau

The population growth in Guinea Bissau is evaluated by the International Monetary
Fund to 2.4% per year during the last 10 years and is forecasted to be of 2.9% per
year for the coming years. The population of Guinea Bissau is estimated to 1.7
millions in 2011.

Since 2001, the annual GDP growth in Guinea Bissau is around 3% except for the
year 2003 when a negative growth was observed according to the IMF. This growth
should continue in the future.

Nevertheless, the load growth is limited by the degradation of quality of service. For
this reason, it is difficult to establish a correlation between the growth of socioeconomic parameters and the load growth.

Within the framework of the update of the master plan of the West African area, it is
important to consider not only the customers currently connected to the network but
also the potential customers. Consequently, the load forecast in Bissau, the
connection of new customers and the connection of isolated centers are taken into
account in the load forecast. Lastly, the mining demand is considered.

third parties is forbidden without prior written approval
to
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

|  | Base scenario\[GWh\] | Low scenario\[GWh\] | Mines\[GWh\] | Base scenario\[MW\] | Low scenario\[MW\] | Mines\[MW\] |
| --- | --- | --- | --- | --- | --- | --- |
| 2011 | 141 | 141 |  | 29 | 29 |  |
| 2012 | 149 | 147 |  | 32 | 31 |  |
| 2013 | 157 | 153 |  | 34 | 32 |  |
| 2014 | 167 | 160 |  | 36 | 33 |  |
| 2015 | 176 | 167 |  | 38 | 35 |  |
| 2016 | 187 | 174 | 351 | 40 | 36 | 50 |
| 2017 | 233 | 182 | 351 | 50 | 38 | 50 |
| 2018 | 281 | 221 | 351 | 60 | 46 | 50 |
| 2019 | 332 | 263 | 351 | 71 | 54 | 50 |
| 2020 | 385 | 306 | 701 | 83 | 64 | 100 |
| 2021 | 441 | 352 | 701 | 95 | 73 | 100 |
| 2022 | 465 | 399 | 701 | 100 | 83 | 100 |
| 2023 | 491 | 418 | 701 | 106 | 87 | 100 |
| 2024 | 517 | 438 | 701 | 111 | 91 | 100 |
| 2025 | 545 | 458 | 701 | 117 | 95 | 100 |

Table 8 - Load forecast in Guinea Bissau

Guinea

Between 2000 and 2010, the annual growth rate of the population in Guinea did not
stop increasing. This rate was estimated by the International Monetary Fund to 1.9%
per year in the beginning of the year 2000 and to 2.5% in 2010. Today, the
population of Guinea is estimated to 10.6 millions.

Nevertheless, the load growth is limited by the degradation of quality of service. For
this reason, it is difficult to establish a correlation between the growth of socioeconomic parameters and the load growth.

The load forecast in Guinea is thus established by taking into account various
aspects:

• Resorption of the unserved demand over a 6 years period;
The connection of isolated centers:

• The connection of isolated centers:
-The center of Nzerekoré should be connected to the interconnected network

-The center of Nzerekoré should be connected to the interconnected network
thanks to the CLSG line and the Guinea-Mali line;
-The center of Kankan will be connected to the interconnected network with

-The center of Kankan will be connected to the interconnected network with
the commissioning of the Guinea-Mali interconnection;
-The center of Faranah is located near the routing of the Linsan-Fomi line.

• The mining sector.

-The center of Faranah is located near the routing of the Linsan-Fomi line.

third parties is forbidden without prior written approval
to
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

|  | Base scenario\[GWh\] | Low scenario\[GWh\] | Mines\[GWh\] | Base scenario\[GWh\] | Low scenario\[GWh\] | Mines |
| --- | --- | --- | --- | --- | --- | --- |
| 2011 | 608 | 608 |  | 139 | 139 |  |
| 2012 | 760 | 687 |  | 164 | 148 |  |
| 2013 | 934 | 760 |  | 190 | 155 |  |
| 2014 | 1102 | 934 |  | 221 | 181 |  |
| 2015 | 1563 | 1131 |  | 287 | 216 |  |
| 2016 | 1718 | 1406 | 2643 | 302 | 247 | 377 |
| 2017 | 1766 | 1622 | 2682 | 311 | 286 | 383 |
| 2018 | 1819 | 1666 | 2723 | 321 | 293 | 389 |
| 2019 | 1875 | 1712 | 4864 | 330 | 302 | 694 |
| 2020 | 1937 | 1763 | 4936 | 340 | 309 | 704 |
| 2021 | 2032 | 1842 | 5011 | 357 | 324 | 715 |
| 2022 | 2101 | 1899 | 5086 | 369 | 334 | 726 |
| 2023 | 2170 | 1955 | 5162 | 381 | 343 | 737 |
| 2024 | 2238 | 2012 | 5239 | 393 | 353 | 748 |
| 2025 | 2308 | 2067 | 5318 | 405 | 363 | 759 |

Table 9 - Load forecast in Guinea

Sierra Leone

Between 2000 and 2005, the population growth in Sierra Leone was estimated by
the International Monetary Fund to 3.7% per year. Today the population growth is
rather estimated to 2.6% per year. The population of Sierra Leone is estimated to 6
millions in 2011.

The majority of electrical installations were destroyed during the civil war in Sierra
Leone. The rebuilding is underway but the majority of the areas located inside the
country do not have access to electricity.

Today, the demand is primarily urban (residential and tertiary). Consumption
follows the availability of the production.

Consequently, the load forecast in Sierra Leone takes 3 aspects into account:

• The load growth in the already interconnected areas;
the rural electrification;

• the rural electrification;
the mining load (considered with a load factor of 80%).

• the mining load (considered with a load factor of 80%).

third parties is forbidden without prior written approval
to
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

|  | Base scenario\[GWh\] | Low scenario\[GWh\] | Mines\[GWh\] | Base scenario\[MW\] | Low scenario\[MW\] |
| --- | --- | --- | --- | --- | --- |
| 2011 | 202 | 162 | 350 | 38 | 30 |
| 2012 | 267 | 214 | 350 | 50 | 40 |
| 2013 | 363 | 291 | 631 | 68 | 54 |
| 2014 | 486 | 389 | 911 | 91 | 73 |
| 2015 | 587 | 470 | 911 | 110 | 88 |
| 2016 | 715 | 572 | 1612 | 134 | 107 |
| 2017 | 789 | 631 | 2313 | 148 | 118 |
| 2018 | 828 | 663 | 3013 | 155 | 124 |
| 2019 | 868 | 694 | 4135 | 162 | 130 |
| 2020 | 907 | 726 | 5256 | 170 | 136 |
| 2021 | 957 | 766 | 5256 | 179 | 143 |
| 2022 | 1007 | 806 | 5256 | 188 | 151 |
| 2023 | 1057 | 846 | 5256 | 198 | 158 |
| 2024 | 1107 | 886 | 5256 | 207 | 166 |
| 2025 | 1157 | 926 | 5256 | 217 | 173 |

Table 10 -Load forecast in Sierra Leone

Liberia

Today the annual GDP growth is very high in Liberia. It is between 5 and 12% per
year according to the IMF.

The population growth in Liberia is estimated between 3 and 4% by the IMF
depending on the years. Today, there are little less than 4.5 millions inhabitants in
Liberia.

Nevertheless, very few customers are connected to the electrical network. In 2009,
1645 consumers were connected to 4 isolated sub-networks. The growth forecast of
the load is very high for the first years. It is not a matter of natural growth of
consumption but well of an increase in the number of customers connected to the
network. Later on, the rural electrification and the expected increase in the macroeconomic parameters are the key factors of the load growth.

Finally, two types of customers must be considered:

• The customers of Monrovia who are primarily residential and commercial and
for which the load profile is equivalent to the already connected customers;
The mining consumers who will connect themselves to the network in the future

• The mining consumers who will connect themselves to the network in the future
and who have an important load factor.

third parties is forbidden without prior written approval
to
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

|  | Base scenario\[GWh\] | Low scenario\[GWh\] | Mines\[GWh\] | Base scenario\[MW\] | Low scenario\[MW\] | Mines\[MW\] |
| --- | --- | --- | --- | --- | --- | --- |
| 2011 | 47 | 34 |  | 9 | 6 |  |
| 2012 | 105 | 57 | 33 | 20 | 11 | 5 |
| 2013 | 163 | 90 | 131 | 31 | 17 | 20 |
| 2014 | 226 | 125 | 657 | 43 | 24 | 100 |
| 2015 | 263 | 180 | 1.183 | 50 | 34 | 180 |
| 2016 | 279 | 226 | 1.840 | 53 | 43 | 280 |
| 2017 | 296 | 263 | 1.840 | 56 | 50 | 280 |
| 2018 | 314 | 275 | 1.840 | 60 | 53 | 280 |
| 2019 | 334 | 288 | 1.840 | 63 | 54 | 280 |
| 2020 | 355 | 301 | 1.840 | 68 | 58 | 280 |
| 2021 | 378 | 316 | 1.840 | 72 | 60 | 280 |
| 2022 | 402 | 332 | 1.840 | 77 | 64 | 280 |
| 2023 | 428 | 349 | 1.840 | 82 | 67 | 280 |
| 2024 | 455 | 367 | 1.840 | 87 | 70 | 280 |
| 2025 | 484 | 387 | 1.840 | 93 | 74 | 280 |

Table 11 - Forecast of the demand in Liberia

Mali

Between 2000 and 2010, the population growth in Mali was estimated by the
International Monetary Fund to 2.3% per year, while the administrative census with
vocation of civil registery (RAVEC) of Mali estimates the growth to 3.6% per year.
Today, the population of Mali is estimated to 14.5 millions.

The GDP of Mali (at constant price) grew on average of 5% per year during the last
10 years according to the International Monetary Fund.

The population growth is the main motor of the residential and tertiary growth of
electricity consumption and the load forecast is consequently correlated to the
evolution of the population.

In addition, the current growth of consumption on the electrified network contains
rural electrification. For the future, the growth rate of rural electrification is
supposed to be identical to the one of today.

Finally, the isolated centers must be considered because part of these centers will be
connected to the interconnected network in a near future. Moreover, self-producers
Malian Company for the Development of Textile Fibers (CMDT) and the gold
mines are interested by a connection of their load to the interconnected network.

third parties is forbidden without prior written approval
to
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

|  | Base scenario\[GWh\] | Low scenario\[GWh\] | Base scenario\[MW\] | Low scenario\[MW\] |
| --- | --- | --- | --- | --- |
| 2011 | 1.136 | 1.098 | 199 | 192 |
| 2012 | 1.232 | 1.174 | 216 | 206 |
| 2013 | 1.382 | 1.233 | 240 | 216 |
| 2014 | 2.111 | 1.294 | 346 | 227 |
| 2015 | 2.226 | 1.434 | 366 | 249 |
| 2016 | 2.896 | 2.144 | 464 | 352 |
| 2017 | 2.997 | 2.239 | 482 | 368 |
| 2018 | 3.153 | 2.930 | 509 | 470 |
| 2019 | 3.248 | 2.999 | 525 | 482 |
| 2020 | 3.398 | 3.085 | 550 | 497 |
| 2021 | 3.567 | 3.155 | 577 | 509 |
| 2022 | 3.740 | 3.279 | 605 | 529 |
| 2023 | 3.916 | 3.405 | 634 | 549 |
| 2024 | 4.097 | 3.534 | 663 | 570 |
| 2025 | 4.282 | 3.665 | 693 | 591 |

Table 12 -Load forecast in Mali

Ivory Coast

Between 2000 and 2010, the growth rate of the population in Ivory Coast was
estimated to nearly 3% per year by the International Monetary Fund. Today the
population of Ivory Coast is estimated to 22.7 millions.

The GDP of Ivory Coast (at constant price) has suffered a period of stagnation and
even of decrease in the beginning of the year 2000. Today, it is believed to be of
approximately 3% per year according to the International Monetary Fund.

According to the bulletin of annual statistics of the ICE, nearly 55% of the produced
energy is consumed by the residential sector. The rest is consumed by the private
and public services (15%) and industries (30%). Consequently, in Ivory Coast, the
increase in population and the increase in the GDP must be weighed against in order
to take into account the various types of consumers.

Lastly, the electric sector undertook several projects for the electrification and
connection to the interconnected network of the isolated centers. The increase in the
level of service by means of the progressive connection of isolated centers with the
interconnected network should result in stabilization, or at least to a fall of the
production in the isolated centers.

third parties is forbidden without prior written approval
to
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

|  | Base scenario\[GWh\] | Low scenario\[GWh\] | Base scenario\[MW\] | Low scenario\[MW\] |
| --- | --- | --- | --- | --- |
| 2011 | 6.005 | 5.859 | 968 | 945 |
| 2012 | 6.390 | 6.131 | 1.030 | 989 |
| 2013 | 6.799 | 6.410 | 1.096 | 1.034 |
| 2014 | 7.245 | 6.696 | 1.168 | 1.080 |
| 2015 | 7.731 | 6.990 | 1.247 | 1.127 |
| 2016 | 8.197 | 7.291 | 1.322 | 1.176 |
| 2017 | 8.680 | 7.600 | 1.400 | 1.225 |
| 2018 | 9.182 | 7.917 | 1.480 | 1.276 |
| 2019 | 9.703 | 8.241 | 1.564 | 1.329 |
| 2020 | 10.244 | 8.574 | 1.652 | 1.382 |
| 2021 | 10.807 | 8.915 | 1.742 | 1.437 |
| 2022 | 11.391 | 9.265 | 1.837 | 1.494 |
| 2023 | 11.998 | 9.624 | 1.934 | 1.552 |
| 2024 | 12.628 | 9.992 | 2.036 | 1.611 |
| 2025 | 13.284 | 10.369 | 2.142 | 1.672 |

Table 13 - Load forecast in Ivory Coast

Ghana

Between 2000 and 2010, the population growth in Ghana was estimated by the
International Monetary Fund to 2.5% per year. Today, the population of Ghana is
estimated to 24 millions.

Given the importance of the industrial customer VALCO, the Consultant proposes to
consider separately the domestic load and VALCO.

The historical data used in the study of correlation of the load of the country are the
population, the GDP, the GDP per capita, the produced energy, the consumed
energy of the country and the total consumed energy. The GDP per capita was used
to approach the income per capita that was not available.
The forecast of the industrial load for the base case is based on the assumption that

The forecast of the industrial load for the base case is based on the assumption that
two production lines would be exploited at VALCO in 2011. VALCO would also be
able to bring into service three lines in 2013. For the low scenario, the assumption
has been made that a production line would be exploited at VALCO in 2011.
VALCO would also be able to bring two lines into service in 2013.

third parties is forbidden without prior written approval
to
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

|  | Base scenario |  | Low scenario |  | Base scenario |  | Low scenario |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- |
|  | Domestic consumption\[GWh\] | VALCO\[GWh\] | Domestic consumption\[GWh\] | VALCO\[GWh\] | Domestic consumption\[MW\] | VALCO\[MW\] | Domestic consumption\[MW\] | VALCO\[MW\] |
| 2011 | 9.793 | 1.314 | 9.239 | 657 | 1.479 | 150 | 1.395 | 75 |
| 2012 | 10.421 | 1.314 | 9.652 | 657 | 1.573 | 150 | 1.457 | 75 |
| 2013 | 11.093 | 1.971 | 10.096 | 1.314 | 1.675 | 225 | 1.524 | 150 |
| 2014 | 11.764 | 1.971 | 10.522 | 1.314 | 1.780 | 225 | 1.590 | 150 |
| 2015 | 12.484 | 1.971 | 10.971 | 1.314 | 1.888 | 225 | 1.657 | 150 |
| 2016 | 13.252 | 1.971 | 11.440 | 1.314 | 2.007 | 225 | 1.730 | 150 |
| 2017 | 14.070 | 1.971 | 11.932 | 1.314 | 2.130 | 225 | 1.804 | 150 |
| 2018 | 14.941 | 1.971 | 12.446 | 1.314 | 2.262 | 225 | 1.881 | 150 |
| 2019 | 15.869 | 1.971 | 12.984 | 1.314 | 2.401 | 225 | 1.962 | 150 |
| 2020 | 16.857 | 1.971 | 13.547 | 1.314 | 2.550 | 225 | 2.047 | 150 |
| 2021 | 17.908 | 1.971 | 14.135 | 1.314 | 2.708 | 225 | 2.136 | 150 |
| 2022 | 19.027 | 1.971 | 14.750 | 1.314 | 2.877 | 225 | 2.228 | 150 |
| 2023 | 20.218 | 1.971 | 15.393 | 1.314 | 3.056 | 225 | 2.325 | 150 |
| 2024 | 21.485 | 1.971 | 16.065 | 1.314 | 3.247 | 225 | 2.426 | 150 |
| 2025 | 22.832 | 1.971 | 16.768 | 1.314 | 3.450 | 225 | 2.532 | 150 |

Table 14 - Forecast of the load demand in Ghana

Togo-Benin

In Benin, the GDP growth was relatively constant these ten last years with an annual
growth rate between 3% and 5% according to the IMF.

The growth of the population of Benin reached 3.3% per year until 2005 and 2.8%
per year since 2006. The population of Benin is of nearly 10 millions inhabitants.

In Togo, the GDP growth was negative in the beginning of the year 2000. Since
2003, the GDP grows on average of 2.5% per year.
In Togo, the annual population growth is of nearly 2.5%. There are currently a little

In Togo, the annual population growth is of nearly 2.5%. There are currently a little
more than 7 millions inhabitants in Togo according to the estimates of the IMF.

The electricity sector in Togo and Benin is governed by the International Agreement
and Benino-Togolese Code for electricity signed between the two states in 1968 and
creating a community of interest between the two countries in the field of electrical
energy.

This code gave to the Electric Community of Benin the monopoly of the production,
transport and the imports/exports of electrical energy on the whole territory of the
two states.

Nevertheless, the International Agreement and Benino-Togolese Code signed in
1968 were revised in 2003. The clauses of the new agreement and Code of 2003 are
hence now on in force. In accordance with the clauses of this new agreement and
revised Benino-Togolese Code of 2003, the CEB does not have the monopoly of the
electrical production anymore. The segment of the electrical production is opened to
independent producers but the CEB remains the single purchaser of their production
everywhere where their network is present.

Nevertheless, the International Agreement and Benino-Togolese Code signed in
1968 were revised in 2003. The clauses of the new agreement and Code of 2003 are
hence now on in force. In accordance with the clauses of this new agreement and
revised Benino-Togolese Code of 2003, the CEB does not have the monopoly of the
electrical production anymore. The segment of the electrical production is opened to
independent producers but the CEB remains the single purchaser of their production

third parties is forbidden without prior written approval
to
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

For this reason, the energy data are available for both states together and not for
each one independently from the other. The study of the demand relates hence to the
Togo-Benin community based on information from the CEB.

The five main customers of the CEB are:

• In Togo:
-CEET: Electrical Energy Company of Togo, national company of distribution

-CEET: Electrical Energy Company of Togo, national company of distribution
of electricity;
-WACEM: West African Cement, producer of cement;

-WACEM: West African Cement, producer of cement;
-SNPT: New Company of Phosphates of Togo, phosphate producer.

-SNPT: New Company of Phosphates of Togo, phosphate producer.
In Benin:

• In Benin:

-SBEE: Beninese company of Electrical energy, national company of
distribution of electricity;
-SCB - Lafarge: Cement producer.

-SCB - Lafarge: Cement producer.
The main industrial customers account for approximately 15% of the demand for

The main industrial customers account for approximately 15% of the demand for
electricity. The rest of the demand is transferred to the Togolese and Beninese
supply firms that act partially as self-producers since they have their own means of
production. The demand of these customers is primarily residential and tertiary.

In the north of Benin, the SBEE works in collaboration with the Beninese Agency
for Rural electrification and Energy Control (ABERME) to develop the 33kV
network between localities and to try to connect the new loads and the isolated
places. Thus, in the short term, Togo and Benin (to a lesser extent) envisage a
considerable growth of the number of customers connected to the interconnected
network. This tendency results in a strong growth of the load which started in 2009
and which should continue until 2012 according to the document “Load forecasts
horizon 2020”.

Currently, Benin consumes more than half of the demand for electricity of the
community. Nevertheless, for several years a more important increase in the load in
Togo than Benin has been observed. The increase in the number of customers
connected to the interconnected network of the CEET should confirm the tendency
and Togo should occupy an increasingly important place in the consumption of
electricity of the community.

Taking into account all these aspects, the load forecast for Togo and Benin are
presented hereafter.

third parties is forbidden without prior written approval
to
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

|  | Togo |  |  |  | Benin |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- |
|  | Base scenario\[GWh\] | Low scenario\[GWh\] | Base scenario\[MW\] | Low scenario\[MW\] | Base scenario\[GWh\] | Low scenario\[GWh\] | Base scenario\[MW\] | Low scenario\[MW\] |
| 2011 | 1042 | 1035 | 170 | 169 | 1341 | 1333 | 219 | 217 |
| 2012 | 1294 | 1286 | 211 | 210 | 1469 | 1460 | 240 | 238 |
| 2013 | 1440 | 1405 | 235 | 229 | 1564 | 1526 | 255 | 249 |
| 2014 | 1571 | 1503 | 256 | 245 | 1697 | 1624 | 277 | 265 |
| 2015 | 1712 | 1608 | 279 | 262 | 1835 | 1723 | 299 | 281 |
| 2016 | 1873 | 1728 | 305 | 282 | 1968 | 1816 | 321 | 296 |
| 2017 | 2046 | 1856 | 334 | 303 | 2105 | 1910 | 343 | 311 |
| 2018 | 2230 | 1990 | 364 | 325 | 2248 | 2006 | 366 | 327 |
| 2019 | 2426 | 2131 | 395 | 348 | 2396 | 2105 | 391 | 343 |
| 2020 | 2609 | 2257 | 426 | 368 | 2576 | 2229 | 420 | 364 |
| 2021 | 2801 | 2387 | 457 | 389 | 2766 | 2358 | 451 | 385 |
| 2022 | 3004 | 2523 | 490 | 412 | 2967 | 2492 | 484 | 407 |
| 2023 | 3217 | 2664 | 525 | 435 | 3178 | 2632 | 518 | 429 |
| 2024 | 3442 | 2812 | 561 | 458 | 3400 | 2777 | 555 | 453 |
| 2025 | 3680 | 2965 | 600 | 484 | 3634 | 2928 | 593 | 477 |

Table 15 - Load forecast in Togo and Benin

Burkina Faso

At the beginning of the year 2000, the annual growth of the population in Burkina
Faso was higher than 3%. Since 2005, the growth slowed down to 2.3% per year
according to the International Monetary Fund. Today, the population of Burkina
Faso is estimated to 15 millions.

The GDP in Burkina Faso (at constant price) grew on average of 5% per year during
the last 10 years according to the International Monetary Fund.

Until 2009, Burkina Faso had two networks independent from each other. Since
2009, these two networks are interconnected (Interconnected National Network:
RNI).

In Burkina Faso, the demand growth is strongly related to the electrification rate.
This electrification rate is correlated to the wealth of the country. For this reason, the
principal macro-economic parameter which guides the evolution of the yearly
consumption of electricity is the GDP.
The energy not served in the areas connected to the interconnected networks was

• An increased unavailability of the interconnection with Ivory Coast.
In addition, rural electrification is a major concern for the SONABEL. The

The energy not served in the areas connected to the interconnected networks was
very low until a few years ago. Nevertheless, it increased in a considerable way
these last years. The main causes for load sheddings are:

third parties is forbidden without prior written approval
to
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

Finally, an ambitious program of connection of the isolated centers is envisaged in
the short and medium term.

Taking into account these aspects leads to the following forecast:

|  | Base scenario\[GWh\] | Low scenario\[GWh\] | Base scenario\[MW\] | Low scenario\[MW\] |
| --- | --- | --- | --- | --- |
| 2011 | 873 | 873 | 178 | 178 |
| 2012 | 934 | 929 | 190 | 189 |
| 2013 | 1.006 | 987 | 205 | 201 |
| 2014 | 1.087 | 1.048 | 222 | 214 |
| 2015 | 1.173 | 1.112 | 239 | 227 |
| 2016 | 1.265 | 1.179 | 258 | 240 |
| 2017 | 1.362 | 1.250 | 278 | 255 |
| 2018 | 1.466 | 1.324 | 299 | 270 |
| 2019 | 1.576 | 1.402 | 321 | 286 |
| 2020 | 1.694 | 1.484 | 345 | 303 |
| 2021 | 1.820 | 1.570 | 371 | 320 |
| 2022 | 1.953 | 1.661 | 398 | 338 |
| 2023 | 2.095 | 1.755 | 427 | 358 |
| 2024 | 2.247 | 1.855 | 458 | 378 |
| 2025 | 2.408 | 1.959 | 491 | 399 |

Table 16 - Load forecast in Burkina Faso

Niger

The historical analysis of the demographical and economical data and of electricity
consumptions is the preliminary stage to the projections of demand.

Between 2000 and 2010 the population growth in Niger was estimated by the
International Monetary Fund to 3.1% per year. Today, the population of Niger is
estamated to 15.2 million (source: INS-Niger).

The GDP of Niger (at constant price) grew on average of 4.8% per year over the last
10 years according to the International Monetary Fund.

There are 4 zones in Niger:

• The River area, around Niamey, supplied by Birnin Kebbi in Nigeria;
The Center-East area, supplied by Katsina in Nigeria;

• The Center-East area, supplied by Katsina in Nigeria;
The East area: 33 kV zone, supplied by Nigeria in 33 kV;

The three first are supplied by Nigeria and are synchronous. There are emergency
power plants (cold reserve). The fourth one is supplied by a coal plant.

• The East area: 33 kV zone, supplied by Nigeria in 33 kV;
• The Northern area, close to Agadez.

In Niger, the demand is primarily residential and industrial. The residential sector
accounts for 47% of electric consumption, while services account for 13% of this
consumption. In addition, industries account for 39% of the load, according to the
2007 annual report of the Energy Information System of Niger (EIS).

• The Northern area, close to Agadez.

third parties is forbidden without prior written approval
to
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

In addition, in Niger, the connection of new customers following the implementation
of the special program of the President of the Republic and the execution of the
Development project of the interconnected electrical network of Niger DREIN made
it possible to electrify several rural localities. The consumption of electricity in the
interconnected network consequently grew steadily these last years. A rise of 88% of
the demand in terms of “demanded energy” (524 GWh in 2008) has been recorded
between years 2000 and 2008.

In addition, in Niger, the connection of new customers following the implementation
of the special program of the President of the Republic and the execution of the
Development project of the interconnected electrical network of Niger DREIN made
it possible to electrify several rural localities. The consumption of electricity in the
interconnected network consequently grew steadily these last years. A rise of 88% of
the demand in terms of “demanded energy” (524 GWh in 2008) has been recorded

Finally, the connection of a cement factory of 20MW is considered in the Center-
East area as from 2015

|  | Base scenario |  |  |  |  | Low scenario |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
|  | River\[GWh\] | Center East\[GWh\] | East\[GWh\] | North\[GWh\] | Total\[GWh\] | River\[GWh\] | Center East\[GWh\] | East\[GWh\] | North\[GWh\] | Total\[GWh\] |
| 2011 | 429 | 249 | 62 | 109 | 849 | 422 | 245 | 61 | 107 | 835 |
| 2012 | 461 | 267 | 67 | 117 | 912 | 446 | 258 | 65 | 113 | 882 |
| 2013 | 494 | 286 | 72 | 125 | 977 | 470 | 273 | 68 | 119 | 931 |
| 2014 | 528 | 306 | 76 | 134 | 1.044 | 496 | 287 | 72 | 126 | 980 |
| 2015 | 535 | 433 | 132 | 136 | 1.235 | 494 | 409 | 126 | 125 | 1.154 |
| 2016 | 569 | 452 | 141 | 144 | 1.306 | 518 | 423 | 133 | 131 | 1.205 |
| 2017 | 604 | 473 | 149 | 153 | 1.379 | 544 | 438 | 139 | 138 | 1.258 |
| 2018 | 640 | 493 | 158 | 162 | 1.454 | 570 | 453 | 146 | 144 | 1.312 |
| 2019 | 677 | 515 | 167 | 172 | 1.530 | 596 | 468 | 152 | 151 | 1.368 |
| 2020 | 715 | 537 | 177 | 181 | 1.609 | 623 | 484 | 159 | 158 | 1.424 |
| 2021 | 754 | 559 | 187 | 191 | 1.691 | 651 | 500 | 166 | 165 | 1.482 |
| 2022 | 794 | 583 | 197 | 201 | 1.774 | 679 | 516 | 174 | 172 | 1.541 |
| 2023 | 835 | 607 | 207 | 212 | 1.860 | 707 | 533 | 181 | 179 | 1.601 |
| 2024 | 877 | 631 | 217 | 223 | 1.948 | 737 | 550 | 188 | 187 | 1.662 |
| 2025 | 921 | 656 | 228 | 234 | 2.039 | 767 | 567 | 196 | 194 | 1.725 |
|  | Base scenario |  |  |  |  | Low scenario |  |  |  |  |
|  | River\[MW\] | Center East\[MW\] | East\[MW\] | North\[MW\] | Total\[MW\] | River\[MW\] | Center East\[MW\] | East\[MW\] | North\[MW\] | Total\[MW\] |
| 2011 | 86 | 22 | 3 | 38 | 149 | 85 | 21 | 3 | 37 | 146 |
| 2012 | 93 | 23 | 4 | 41 | 160 | 90 | 22 | 4 | 39 | 154 |
| 2013 | 99 | 25 | 4 | 43 | 171 | 94 | 24 | 4 | 41 | 163 |
| 2014 | 106 | 26 | 4 | 46 | 183 | 99 | 25 | 4 | 44 | 172 |

Table 17 - Load forecast in Niger

third parties is forbidden without prior written approval
to
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

Nigeria

The population growth in Nigeria is evaluated by the International Monetary Fund to
2.7% per year. The population of Nigeria reached 160 millions in 2011.

Since 2001, the annual GDP growth in Nigeria varied between 5% and 10% except
for the year 2002 when an exceptional growth of 21% was observed according to the
IMF.

Given the quantity of energy not served in Nigeria, it is difficult to draw up a
correlation study between the demand and the macro-economic parameters over the
last 10 years.

The park of production has not been reinforced in Nigeria since 2006. The
resorption of the demand could consequently not start. On the contrary, not served
energy did nothing but increase given the constant decrease of the energy produced
since 2006.

PHCN (Power Holding Company of Nigeria) estimates the demand to be supplied in
Nigeria in 2011 to 9 GW. Nevertheless, PHCN has very ambitious development
plans of production park in the short-term which will allow, if they are carried out,
to reabsorb the unserved demand very quickly.

Taking into account the investment plans in means of production in the short-term in
order to estimate the resorption of the load, the forecast of the served demand should
follow the following tendency, if referred to the vision of PHCN.

|  | Base scenario\[GWh\] | Low scenario\[GWh\] | Base scenario\[MW\] | Low scenario\[MW\] |
| --- | --- | --- | --- | --- |
| 2011 | 39.102 | 25.524 | 6.376 | 4.162 |
| 2012 | 58.069 | 34.570 | 9.471 | 5.638 |
| 2013 | 61.321 | 43.624 | 10.000 | 7.114 |
| 2014 | 64.964 | 56.272 | 10.595 | 9.177 |
| 2015 | 68.830 | 65.178 | 11.225 | 10.629 |
| 2016 | 72.926 | 69.058 | 11.892 | 11.261 |
| 2017 | 77.258 | 72.339 | 12.599 | 11.797 |
| 2018 | 81.856 | 75.784 | 13.348 | 12.358 |
| 2019 | 86.717 | 79.383 | 14.142 | 12.946 |
| 2020 | 91.873 | 83.159 | 14.983 | 13.562 |
| 2021 | 98.732 | 88.365 | 15.874 | 14.207 |
| 2022 | 104.604 | 92.569 | 16.818 | 14.883 |
| 2023 | 110.821 | 96.969 | 17.818 | 15.591 |
| 2024 | 117.412 | 101.584 | 18.877 | 16.333 |
| 2025 | 124.393 | 106.415 | 20.000 | 17.110 |

Table 18 - Load forecast in Nigeria

third parties is forbidden without prior written approval
to
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

2.2.4. Generation data

2.2.4.1. CHARACTERISTICS AND COSTS OF NEW TECHNOLOGIES

Gas Turbines and Combined Cycles

Several countries of the ECOWAS currently have gas turbines (GT) and combined
cycles (CC) running either on natural gas (Ivory Coast, Ghana, Nigeria) or on liquid
fuel (Togo, Ghana, Ivory Coast, Senegal…). The majority of these GT and CC are
dual fuel allowing burning either gas or liquid fuels. Various manufacturers are
represented on the continent (GE, Siemens, Alstom…) and different sizes of gas
turbines are installed from 7.9 MW to 150 MW. In the same way, different CC are
installed presenting powers varying from 50 MW (Senegal) to 450 MW (Nigeria).

During the optimization of the production plan a series of GT and CC known as
standard are regarded as investment option. This serie of GT and CC is proposed in
order to cover a broad range of size and technology.

The sizes suggested for the combined cycles are 60 MW, 300 MW and 450 MW.
These sizes correspond to the orders of magnitude of the standards used in certain
countries of the ECOWAS like Senegal (50MW), Ghana (90MW and 300 MW) and
Nigeria or Ivory Coast (project) (450 MW). No size higher than 450 MW was
proposed for systemic considerations. Indeed, a CC of 450 MW presents a
dimensioning incident of 225 MW (1 GT and ½ ST) which is consequent
considering the size of the West African networks.

The sizes suggested for the GT correspond to the GT of the combined cycles
suggested namely: 45 MW, 100 MW and 150 MW.

In terms of technology, the selection of the GT and CC were made in order to
facilitate maintenance and to minimize the capital costs rather than to maximize the
output. It would be possible to reach one or two additional points of output but at a
very high cost.

For the CC, two cooling methods are proposed, by cooling tower and by direct oulet.
The direct outlet makes it possible to increase by one to two points the total output.

• Planned and unplanned unavailabilities were adapted to the local conditions.
The fuels modeled in Thermoflow are on the one hand the natural gas and on the

• All the CC have a by-pass chimney to allow running the GT while the ST are
unavailable;
Planned and unplanned unavailabilities were adapted to the local conditions.

• All the GT and CC are dual fuel;
• All the CC have a by-pass chimney to allow running the GT while the ST are

• Room temperature of 33°C;
All the GT and CC are dual fuel;

33^{\\circ}\\mathrm{C}

The table below presents the investment data of GT and CC technologies.

third parties is forbidden without prior written approval
to
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

THERMOFLOW CASES

| Plant characteristics | Unit | THERMOFLOW CASES |  |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |  |  |
| Cooling method |  | CCGT (300MW) 2GT + 1ST | CCGT (300MW) 2GT + 1ST | CCGT (450MW) 2GT+1ST | CCGT (450MW) 2GT+1ST | CCGT (60MW) 1GT+1ST | CCGT (60MW) 1GT+1ST | OCGT (45MW) | OCGT (100MW) | OCGT (150MW) |
| GT Manufacturer + Model | - | GE 9E | GE 9E | Air cool Siemens SGT5-2000E Ansaldo AE94.2 GE 9C | Direct Water cool Siemens SGT5-2000E Ansaldo AE94.2 GE 9C | Air cool Siemens SGT800 ALSTOM GT8C2 | Direct Water cool Siemens SGT800 ALSTOM GT8C2 | ALSTOM GT8C2 | Alstom GT11N2 | Siemens SGT5-2000E |
| Alternative GT Manufacturer + Model | - | Alstom GT11N2 | Alstom GT11N2 | 145 | 145 | 39/38 | 39/38 | 49 | 101 | 146 |
| Gross GT Power (Site condition) | MW | 110 | 110 | 2 | 2 | 1 | 1 | 1 | 1 | 1 |
| Number of GT | - | 2 | 2 | 2 | 2 | 1 | 1 | 1 | 1 | 1 |
| ST Manufacturer + Model | - | Siemens SST-900 | Siemens SST-900 | Siemens SST-900 | Siemens SST-900 | SST-300 | SST-300 | NA | NA | NA |
| Number of ST | - | 1 | 1 | 1 | 1 | 1 | 1 | NA | NA | NA |
| Gross ST Power (Site condition) | MW | 123 | 138 | 155 | 173 | 15 | 18 | NA | NA | NA |
| Total Nominal (Gross Power, NG/Oil) | MW | 342/- | 357/- | 445 | 463 | 54/53 | 57/55 | 49/47 | 101 | 146 |
| Total Nominal (net) Power NG/Oil | MW | 332/- | 348/ | 432 | 452 | 53/51 | 55/54 | 48/46.5 | 100 | 144 |
| Net Efficiency | % | 49.1 | 51.5 | 49.3 | 51.6 | 47.9 | 50.2 | 32.1 | 31.6 | 33.1 |
| Total investment cost | MUSD | 334 | 320 | 404 | 386 | 73 | 72 | 41 | 69 | 88 |
| Total investment cost / kW | USD/kw | 977 | 896 | 908 | 834 | 1352 | 1263 | 837 | 683 | 603 |
| Schedule of investment payment(from EPC or EPC(M) contract signature) |  | 16/34/50 | 16/34/50 | 16/34/50 | 16/34/50 | 20/50/30 | 20/50/30 | 50/50 | 50/50 | 50/50 |
| Life duration | %/year | 25 | 25 | 25 | 25 | 25 | 25 | 25 | 25 | 25 |
| Fixed O&M cost | USD/kW | 34 | 31 | 32 | 29 | 38 | 37 | 8.4 | 7 | 6 |
| Variable O&M Cost (excl fuel) | USD/MWh | 1.83 | 1.68 | 1.71 | 1.57 | 2.03 | 2.00 | 2.51 | 2.05 | 1.81 |
| Fuel 1 |  | Natural Gas | Natural Gas | Natural Gas | Natural Gas | Natural Gas | Natural Gas | Natural Gas | Natural Gas | Natural Gas |

to third parties is forbidden without prior written approval
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

Coal

The investments decided, planned and under consideration in Niger and Senegal
concern small units (125MW in Senegal and 4\*50 MW in Niger).

In the absence of concrete data on the technology used, standard investment data
were proposed. The units were selected in order to facilitate maintenance and to
minimize the capital costs rather than to maximize the output. It would be possible
to reach one or two additional points of output but at a very high cost.

In a general way, two technologies would be considered:

• “Circulating Fluidized Bed” (CFB) Technology;
“Pulverized Coal” (PC) Technology.

• “Pulverized Coal” (PC) Technology.
The Consultant used the Thermo flow software to estimate the investments and the

The Consultant used the Thermo flow software to estimate the investments and the
operation costs of the various configurations. This software simulates the
thermodynamic cycle of the power plant based on selected component of the power
plant. It informs of the net efficiency expected and thus of the specific consumption.
The principal assumptions are summarized hereafter:

• Room temperature of 33°C;
Planned and unplanned unavailabilities were adapted to the local conditions.

33^{\\circ}\\mathbf{C};

• Planned and unplanned unavailabilities were adapted to the local conditions.
The table below presents the investment data of coal technologies. Being given the

The table below presents the investment data of coal technologies. Being given the
size of the investments suggested for Senegal and Niger, it is the CFB technology
that has been selected.

|  |  | Thermoflow Cases |  |
| --- | --- | --- | --- |
|  |  | 10 | 11 |
| Plant characteristics | Unit | Coal(125MW)Type:CFB | Coal(250MW)Type:PC |
| Number of ST | - | 1 | 1 |
| Gross ST power(Site condition) | MW | 125 | 250 |
| Total Nominal(Gross)PowerNG/Oil | MW | 125 | 250 |
| Total Nominal(net)PowerNG/Oil | MW | 116 | 230 |
| Net Efficiency | % | 37.6 | 39 |
| Total investment cost | MUSD | 314 | 540 |
| Total investment cost/kW | USD/kw | 2512 | 2160 |
| Schedule of investment payment(fromEPC orEPC(M)contract signature) | %/year | 16/32/32/20over3,3 years | 16/32/32/20over3,3 years |
| Life duration | years | 35 | 35 |
| FixedO&Mcost | USD/kW | 75 | 65 |
| VariableO&MCost(excl fuel) | USD/MWh | 3.14 | 2.7 |
| Fuel1 |  | Coal | Coal |
| LHV net heat rate-Fuel1 | kJ/kWh | 9574 | 9231 |
| Fuel2 |  | Oil,biomass | Oil,biomass |
| LHV net heat rate-Fuel2 | kJ/kWh |  |  |
| emission levelCO2 | T/h | 106 | 206 |
| emission levelS02(Distillate Oil) | T/h | 0,053 | 0,103 |
| emission levelNox(WithoutSCR) | ppmV(dry) | N.A | N.A |
| emission levelNoxwithSCR | ppmV(dry) | 97(SNCR) | 96(SNCR) |
| Planned availability(maintenance) | pu | 7% | 7% |
| Unplanned availability(forced outage) | pu | 8% | 8% |

High speed and medium-speed diesel

Table 20 - Coal center – Investment data

A vast majority of the ECOWAS countries uses high-speed or medium-speed diesel
groups running on diesel (DDO) or heavy fuel oil (HFO). These groups present
powers varying from less than 1 MW to approximately 20 MW.

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

The advantages of these diesel groups are their relatively low capital cost, the
construction speed and the facility of storage and supply of fuels. Their big
disadvantages are the high fuels costs, their relatively high specific consumption and
expensive maintenance.

During the optimization of the production plan a series of high-speed and mediumspeed diesels groups known as standard are regarded as an investment option. This
series of diesels groups is proposed in order to cover a broad range in terms of size
and technology.

The table below presents the investment data for diesel technologies.

| Plant characteristics | Unit | HFO 10MW | HFO 20MW | DDO 10MW |
| --- | --- | --- | --- | --- |
| Total Nominal(net)Power | MW | 10 | 20 | 10 |
| Net Efficiency | % | 40% | 40% | 36% |
| Total investment cost | MUSD | 14.5 | 27 | 10.7 |
| Total investment cost/kW | USD/kw | 1450 | 1350 | 1070 |
| Schedule of investment payment(from EPC or EPC(M) contract signature) | %/year | 50%/50% | 50%/50% | 50%/50% |
| Life duration | year | over 2 years | over 2 years | over 2 years |
| Fixed O&M cost | USD/kW | 16.8 | 16.8 | 8.4 |
| Variable O&M Cost(excl fuel) | USD/MWh | 7.1 | 7.1 | 10.1 |
| Fuel1 |  | HFO | HFO | DDO |
| LHV net heat rate-Fuel1 | kJ/kWh | 9000 | 9000 | 10000 |
| emission levelCO2 | kg/MWh | 712.8 | 712.8 | 741 |
| emission levelS02(Distillate Oil) | kg/MWh | 4.1 | 4.1 | 0.9 |
| Planned availability(maintenance) | pu | 7% | 7% | 7% |
| Unplanned availability(forced outage) | pu | 10% | 10% | 10% |

Table 21 - Diesel - Investment data

Biomass

Some countries such as Senegal, Liberia and Sierra Leone consider biomass in their
energy mix.
In the absence of concrete data on the technology used, standard investment data

In the absence of concrete data on the technology used, standard investment data
were proposed. The units were selected in order to facilitate maintenance and to
minimize the capital costs rather than to maximize the output. It would be possible
to reach one or two additional points of output but at a very high cost.

The table below presents the investment data of technologies using biomass. Given
the size of the investments suggested for Senegal, Liberia and Sierra Leone, it is the
CFB technology thta has been selected. According to the size of the projects, the
data are variable.

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

| Type of equipment | Unit | Large Biomass Plant (100MWe) | Medium Biomass Plant (40MWe) | Small Biomass Plant (5MWe) |
| --- | --- | --- | --- | --- |
| Manufacturer+Model | - | CFB Boiler | CFB Boiler | Grate Furnace |
| Number of ST | - | 1 | 1 | 1 |
| nominal capacity of ST at site condition(32°) | MW | 100 | 40 | 5 |
| Total Nominal Power | MW | 100 | 40 | 5 |
| Total investment cost | MUSD | 324 | 136 | 34 |
|  |  | Y0-3:45% | Y0-3:45% |  |
| Schedule of investment payment |  | Y0-2:25% | Y0-2:25% | Y0-1:55% |
|  | Y0-1:10% | Y0-1:10% | Y0:45% |  |
| %/year | Y0:20% | Y0:20% |  |  |
| Total investment/kW | USD/kW | 3240 | 3400 | 6800 |
| Life duration | years | 30 | 30 | 30 |
| Discount rate | % | 12 | 12 | 12 |
| Fixed O&M cost(OPEX) | USD/kW/y | 130 | 136 | 272 |
| Variable O&M Cost(excl fuel) | USD/MWh | included | included | included |
| Fuel 1 |  | Wood Chips | Wood Chips | Wood Chips |
| LHV net heat rate(32°)-Fuel 1 | kJ/kWh | 9600 | 9600 | 15000 |
| emission level CO2 | mg/Nm3 | 0 | 0 | 0 |
| emission level SO2 | mg/Nm3 | - | - | - |
| emission level Nox without DeNox | mg/Nm3 | 250 | 250 | 250 |
| emission level Nox with DeNox(SNCR) | mg/Nm3 | 125 | 125 | 125 |
| Planned availability(maintenance) | pu | 7% | 7% | 7% |
| Unplanned availability(forced outage) | pu | 8% | 8% | 8% |
| Pecularities |  |  |  |  |
| -Average Available Energy | GWh | 745 | 300 | 37 |
| -Fuel consumption | t/year | 510000 | 204000 | 40000 |
| -Fuel cost in Africa if available on site | USD/GJ | 3.6 | 3.6 | 3.6 |
| -Fuel cost in Africa if transport needed | USD/GJ | 5.1 | 5.1 | 5.1 |

Table 22 - Biomass Production unit - Investment data

third parties is forbidden without prior written approval
to
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

Hydroelectricity

One of the objectives of this master plan and of the national Master plans of the
majority of West African countries is the development of the not yet exploited
hydroelectric resources. These resources are very abundant and are mainly
distributed in the basins of the Senegal, Niger, The Gambia and Konkouré Rivers.

These projects are taken into account as investment options during the optimization
of the production plan and are thus put in competition with the other technologies
presented in this chapter.

Nevertheless, it should be noted that the projects suggested in the countries of zone
B can not reasonably be all set up by 2025 even if many of them are profitable from
an economic point of view. Indeed, the financial limits of the countries, the
environmental impacts, and the difficulties of accessibility are as many brakes to the
massive development of the hydroelectricity. Moreover, a certain number of these
projects could be dedicated to the local supply of the mining sector.

In the first two scenarios (without limits of interconnection and national
development), no constraint was forced on the model in order to take these aspects
into account.

Nevertheless, in order to obtain a reference case which can be used as a basis for the
development of a list of priority investments, some constraints were forced based on
the limits evoked herebefore and limiting the disproportionate investments in the
countries having many hydroelectric resources.

The characteristics of the projects were determined based on the last available study
for each work. When certain data such as the capital cost or the annual potential
production were not available, the Consultant proposed values based on the site
location, the type of installation and the power of the groups. These values are
showed in italic.

to third parties is forbidden without prior written approval
ny duplication or transmission
the property of Tractebel Engineering S.A. A
This document is

* * *

| Node | Name Power Plant | Status | Installed capacity \[MW\] | Total costs \[MS\] | Spec. Invest. costs\[$/kW\] | Average energy \[GWh/an\] | Guaranteed energy \[GWh/an\] |
| --- | --- | --- | --- | --- | --- | --- | --- |
| Burkina Faso | Bougouriba | Candidate | 12 | 122 | 10125 | 30 | 22.8 |
| Burkina Faso | Bagre Downstream |  | 14 | 106 | 7536 | 36 | 27.36 |
| Ivory Coast | Soubré | Candidate | 270 | 620 | 2296 | 1116 | 848 |
| Ivory Coast | Gribo Popoli | Candidate | 112 | 364 | 3249 | 515 | 391 |
| Ivory Coast | Boutoubre | Candidate | 156 | 401 | 2570 | 785 | 597 |
| Ivory Coast | Louga | Candidate | 280 | 1330 | 4751 | 1330 | 1011 |
| Ivory Coast | Tiassale | Candidate | 51 | 207 | 4068 | 215 | 163 |
| Ivory Coast | Aboisso Comoe | Candidate | 90 | 248 | 2756 | 392 | 298 |
| Ghana | Juale | Candidate | 87 | 372 | 4276 | 405 | 308 |
| Ghana | Pwalugu | Candidate | 48 | 209 | 4361 | 184 | 140 |
| Ghana | Daboya | Candidate | 43 | 241 | 5611 | 194 | 147 |
| Ghana | Hemang | Candidate | 93 | 304 | 3270 | 340 | 258 |
| Ghana | Kulpawn | Candidate | 36 | 345 | 9587 | 166 | 126 |
| Guinea | Amaria | Candidate | 300 | 377 | 1256 | 1435 | 1057 |
| Guinea | Bonkon Diaria | Candidate | 174 | 211 | 1213 | 451 | 315 |
| Guinea | Diaraguela | Candidate | 72 | 178 | 2472 | 400 | 298 |
| Guinea | Fetore | Candidate | 124 | 160 | 1290 | 322 | 232 |
| Guinea | Fomi | Candidate | 90 | 156 | 1728 | 374 | 320 |
| Guinea | Frankonedou | Candidate | 36 | 83 | 2306 | 173 | 140 |
| Guinea | Gozoguezia | Candidate | 48 | 110 | 2292 | 259 | 200 |
| Guinea | Grand Kinkon | Candidate | 291 | 298 | 1024 | 720 | 618 |
| Guinea | Kaleta | Decided | 240 | 267 | 1114 | 946 | 228 |
| Guinea | KassaB | Candidate | 135 | 214 | 1585 | 528 | 467 |
| Guinea | Kogbedou | Candidate | 14 | 71 | 5083 | 111 | 99 |
| Guinea | Kouravel | Candidate | 135 | 185 | 1370 | 350 | 240 |
| Guinea | Kouya | Candidate | 86 | 156 | 1814 | 334 | 315 |
| Guinea | Lafou | Candidate | 98 | 128 | 1306 | 255 | 210 |
| Guinea | Morisakano | Candidate | 100 | 260 | 2600 | 523 | 438 |

Table 23 - Hydroelectric projects Investment data (1/2)

to third parties is forbidden without prior written approval
ny duplication or transmission
the property of Tractebel Engineering S.A. A
This document is

* * *

| Node | Name Power Plant | Status | Installed capacity | Total costs | Spec. Invest. costs |  | Average energy | Guarantee d energy |
| --- | --- | --- | --- | --- | --- | --- | --- | --- |
| \[$/kW\] | \[GWh\] | \[GWh\] |  |  |  |  |  |  |
|  |  |  | \[MW\] | \[M$\] |  | \[$/kW\] | \[GWh\] | \[GWh\] |
| Mali | Kénié | Candidate | 34.4 | 126 |  | 3671 | 199 | 163 |
| Mali | Taoussa | Candidate | 25 | 209 |  | 8340 | 108 | 82 |
| Mali | Sotuba 2 | Candidate | 6 | 48 |  | 7943 | 39 | 37 |
| Mali | Markala | Candidate | 10 | 40 |  | 4025 | 53 | 40 |
| Niger | Kandadji | Candidate | 130 | 405 |  | 3115 | 629 | 478 |
| Niger | Gambou | Candidate | 122.5 | 577 |  | 4712 | 528 | 402 |
| Niger | Dyodyonga | Candidate | 26 | 60 |  | 2293 | 112 | 85 |
| Nigeria | Mambilla | Candidate | 2600 | 4000 |  | 1538 | 11214 | 8522 |
| Nigeria | Zungeru | Candidate | 700 | 1077 |  | 1538 | 3019 | 2295 |
| Sierra Leone | Bumbuna II | Decided | 40 | 78 |  | 1950 | 220 | 237 |
| Sierra Leone | Bumbuna III | Candidate | 90 | 176 |  | 1950 | 396 | 317 |
| Sierra Leone | Bumbuna IV V | Candidate | 95 | 185 |  | 1950 | 494 | 463 |
| Sierra Leone | Gummed II | Candidate | 6 | 40 |  | 6709 | 31 | 1 |
| Sierra Leone | Benkongor | Candidate | 200 | 490 |  | 2447 | 1164 | 959 |
| Sierra Leone | Kuse II | Candidate | 91.8 | 235 |  | 2561 | 680 | 549 |
| Sierra Leone | Kambatibo | Candidate | 52.5 | 164 |  | 3120 | 269 | 212 |
| Sierra Leone | Bitmai I | Candidate | 52.5 | 164 |  | 3120 | 268 | 212 |
| Sierra Leone | Bitmai II | Candidate | 36.6 | 130 |  | 3543 | 250 | 211 |
| Togo | Adjarala | Decided | 147 | 333 |  | 2265 | 366 | 237 |
| Togo | Tététou | Candidate | 50 | 159 |  | 3174 | 148 | 112 |
| Benin | Kétou | Candidate | 160 | 337 |  | 2105 | 490 | 372 |
| Burkina / Ghana | Noumbiel | Candidate | 60 | 286 |  | 4767 | 203 | 154 |
| C iv / Liberia | Tiboto | Candidate | 225 | 578 |  | 2570 | 1200 | 912 |
| Liberia/S.L | ManoRiver | Candidate | 180 | 473 |  | 2625 | 795 | 612 |
| OMVG Guinea | Digan | Candidate | 93.3 | 112 |  | 1200 | 243 | 24 |

Table 24 - Hydroelectric projects Investment data (2/2)

to third parties is forbidden without prior written approval
ny duplication or transmission
the property of Tractebel Engineering S.A. A
This document is

* * *

| Characteristics of the power plants | Units | Hydropower |
| --- | --- | --- |
| Life duration | year | 50 |
| Variable O&M Cost(excl fuel) | USD/MWh | 2 |
| Fixed O&M cost | %。 | Included in variable |
| Planned unavailability(maintenance) | pu | 4% |
| Unplanned unavailability | pu | 2% |

Table 25 - Hydroelectric projects standard Parameters

Solar energy

For CSP technologies, the normal direct irradiation (NDI in kWh/m ² /y) is an
essential criterion to define the potential of the sites. Consequently, in the area of
interest, 4 ranges of DNI were defined:

• Nonsuitable < 2.000 kWh/m2/a

• Acceptable 2.001 - 2.200 kWh/m2/a
Good 2.201 - 2.600 kWh/m2/a

• Good 2.201 - 2.600 kWh/m2/a
Excellent >2.600 kWh/m2/a

• Excellent >2.600 kWh/m2/a
This scale is specific to the area and is defined based on DNI data available for the

This scale is specific to the area and is defined based on DNI data available for the
area.

Another key parameter is the latitude which influences the unit losses. The latitudes
considered are of 15°, 20° and 25°. The latitudes of less than 10° are not considered
because they are classified as “nonsuitable” in the DNI scale.

15^{\\circ},20^{\\circ}

25^{\\circ}

10^{\\circ}

30° latitude North
\[Image: Image424\]

\[Image: Image425\]

Figure 6 - DNI and the latitude of the area of interest ( [www.dlr.de](http://www.dlr.de/))

By using Andasol3 as typical unit (50 MW with 7.5h of storage in Spain), we obtain
the data of Table 26 for a DNI of 2400 kWh/m2/a and a latitude of 20 ° North. The
costs considered in Table 26 are the costs for 2009/2010.

20^{\\mathrm}{ ~~o~~}

to third parties is forbidden without prior written approval
ny duplication or transmission
the property of Tractebel Engineering S.A. A
This document is

* * *

| Characteristics of the power plants | Units | Solar thermics(CSP) |
| --- | --- | --- |
| Nominal output(local conditions) | MW | 50 |
| Average available energy available | GWh | 206 |
| Bill book of payment | %/year | 70% Y0-130% Y0 |
| Capital cost | MUSD | 507 |
| Capital cost/kW | USD/kW | 10138 |
| lifespan | year | 25 |
| Operation cost and maintenance-fixed | USD/kW/year | 254 |
| Operation cost and maintenance-variable | USD/MWh | - |
| Output | % | 17% |
| Planned unavailability(maintenance) | pu | 2% |
| Unplanned unavailability | pu | - |
| Characteristics |  |  |
| -storage | H | 7.5 |
| -DNI | kWh/m2/y | 2400 |
| -No.of loops | - | 152 |
| -Surface of the mirrors | m2 | 497000 |

Table 26 - Solar production unit CSP- Given of investment

Traditional investment data for a photovoltaic installation in Europe with an
operating time ratio adapted to the area are presented in Table 27. The costs
considered in Table 27 are costs for 2010/2011.

| Characteristics of the power plants | Units | Solar PV |
| --- | --- | --- |
| Nominal nominal output(local conditions) | MW | 1 |
| Energy available average | GWh | 2 |
| Bill book of payment | %/year | 100% Y0 |
| Capital cost | MUSD | 3.66 |
| Capital cost/kW | USD/kW | 3660 |
| lifespan | year | 20 |
| Operation cost and maintenance-fixed | USD/kW/year | 20 |
| Operation cost and maintenance-variable | USD/MWh | - |
| Output | % | 15% |
| Planned unavailability(maintenance) | pu | 0.50% |
| Unplanned unavailability | pu | 0.75% |
| Characteristics |  |  |
| -storage | H |  |
| -DNI | kWh/m2/y |  |
| -No.of loops | - |  |
| -Surface of the mirrors | m2 |  |

Wind energy

Two wind technologies are proposed as an investment option for the master plan.
The first technology corresponds to the current state of art in terms of wind turbines.
It is a turbine of approximately 2 MW proposed by all the manufacturers (GE,
REPower, Vestas, Gamesa, Siemens, Nordex, Enercon…). This technology is
currently the most widespread.

Table 27 - Solar production PV unit - Investment data

to third parties is forbidden without prior written approval
ny duplication or transmission
the property of Tractebel Engineering S.A. A
This document is

* * *

The second technology suggested consists of a smaller structure, more flexible
which can be installed more easily in distant areas where the traditional wind
turbines are difficult to install. Typically, this technology is proposed by the Vergnet
Company.

| Type of equipment | Unit | Wind turbine(25x2MW) | Wind turbine(50x1MW) |
| --- | --- | --- | --- |
| Total Nominal Power | MW | 50 | 50 |
| Average available Energy(2000 hours) | GWh | 100 | 100 |
| Total investment cost | MUSD | 69 | 81 |
|  |  | 70% Y0-1 | 70% Y0-1 |
| Schedule of investment payment | %/year | 30% Y0 | 30% Y0 |
| Total investment cost/kW | USD/kW | 1485 | 1750 |
| Life duration | years | 20 | 20 |
| Discount rate | % | 12 | 12 |
| Fixed O&M cost | USD/kW/y | 17 | 17 |
| Variable O&M Cost | USD/MWh | 9.5 | 9.5 |
| Planned availability(maintenance) | pu | 1% | 1% |
| Unplanned availability(forced outage) | pu | 4% | 4% |

Table 28 - Wind - Investment data

2.2.4.2. DEVELOPMENT PLANS OF THE PARK OF PRODUCTION

For each country, the development plans of the national park of production
discussed at the time of data collection missions and the big international projects
are considered.

For each Member State, a list of electric production units was drawn up,
distinguishing the existing units from the future units (decided or candidates):

• Existing units: production units having been commissioned before March 2011;
Decided units: units whose construction is undergoing or was decided for an

• Decided units: units whose construction is undergoing or was decided for an
exact date of commissioning (study finished and guaranteed financing);
Candidates units: units for which the studies are not finished yet or for which the

• Candidates units: units for which the studies are not finished yet or for which the
financing was not found yet.
Among the projects suggested by the countries, those which are decided are not

Among the projects suggested by the countries, those which are decided are not
questionable in the production master plan. On the other hand, the candidate projects
belong to the investment options optimized by the software.

-Within the framework of the OMVS also, the power plant of Guinea, for 140
MW is planned in 2017. The share of Senegal is 25% or 35 MW;
-Through the OMVG, Senegal should benefit from 40% of production of the

-Through the OMVG, Senegal should benefit from 40% of production of the
hydroelectric plant of Sambangalou in 2017, or 51MW;
-A coal plant on the site of Sendou (total of 875 MW divided in 7 phases) as of

Senegal

In addition to the projects under consideration by the countries, a series of
“standard” investments are also proposed as investment option. The standard gas
turbines and the combined cycles proposed permit to cover a broad range in terms of
size and technology.

-A coal plant on the site of Sendou (total of 875 MW divided in 7 phases) as of
2016;

to third parties is forbidden without prior written approval
ny duplication or transmission
the property of Tractebel Engineering S.A. A
This document is

* * *

-The hiring of a 50 MW diesel unit in 2011 for a one year duration, with
possibility of renting an additional 100MW;
-The rehabilitation of the C3 and C4 groups of Bel Air (+30MW in 2011 and

-The rehabilitation of the C3 and C4 groups of Bel Air (+30MW in 2011 and
25MW in 2012);

-Extension of the C6 group of Bel-Air: 2 x 15 MW in 2012;
-The commissioning of Koudi II (2 x 15 MW) in 2012;

-The commissioning of Koudi II (2 x 15 MW) in 2012;
-A Biomass unit of 2 x 15 MW with Ross Bethio in 2014. Produced energy

-A Biomass unit of 2 x 15 MW with Ross Bethio in 2014. Produced energy
estimated per year: 236 GWh.
Candidates projects:

• Candidates projects:
-The installation of mobile units on HFO of 40 MW in Tobin (with option for

-The installation of mobile units on HFO of 40 MW in Tobin (with option for
an extra 30MW) and 70MW in the harbour of Bel-Air (one second barge of
70MW is considered) in 2012;

-The following units are planned for the isolated centers:
• 2012:2 x 5 MW HFO in Ziguinchor which will make it possible to stop the

• 2012:2 x 5 MW HFO in Ziguinchor which will make it possible to stop the
hirings of power in this area;
• 2012:2 x 4 MW HFO in Tambacounda.

• 2012:2 x 4 MW HFO in Tambacounda.
A wind site of 125 MW from 2014 onwards;

-A wind site of 125 MW from 2014 onwards;
-A solar park of 7.5 MW in Ziguinchor;

-A solar park of 7.5 MW in Ziguinchor;
-Several diesel units of 30 or 60 MW could be built by independent producers.

-Several diesel units of 30 or 60 MW could be built by independent producers.
The Gambia

The Gambia

• Decided projects:
-Complete commissioning of the units of Kotu;

-Complete commissioning of the units of Kotu;
-The rehabilitation of the unit G6 of Kotu in 2011;

-The rehabilitation of the unit G6 of Kotu in 2011;
-The rehabilitation of the unit G2 (HFO) in Kotu (3 MW) in 2012;

-The rehabilitation of the unit G2 (HFO) in Kotu (3 MW) in 2012;
-The installation of 2 new diesel units of 6.5 MW running on HFO, at the

-The installation of 2 new diesel units of 6.5 MW running on HFO, at the
power plant of Brikama at the end of 2011;
-The installation of an extra 9 MW in Brikama running on HFO also at the end

-Extension of the power plant of Brikama to 2 x 10 MW in 2013;
-A project of an additional 4MW of wind in 2014;

-The installation of an extra 9 MW in Brikama running on HFO also at the end
of 2011;
-4 units of 2 MW running on HFO for the isolated centers;

-4 units of 2 MW running on HFO for the isolated centers;
-Construction of a wind farm of 1 MW in Tanji in 2012.

-Through the OMVG, The Gambia should profit from 12% of the power of the
hydroelectric plans of Sambangalou in 2017, that is 15 MW;
-A solar project of 10MW;

| Area | Current load | New Units | Connection to Banjul |
| --- | --- | --- | --- |
| Farafenni & Mansa Konko | 1.8MW | 2MW in 2013 | 2013 |
| Bansang | 0.6MW | 2MW in 2013 | 2014 |
| EASSAN/Barria | 0.46MW |  | OMVG |
| KEREWAN | 0.22MW | 2MW in 2013 |  |
| LOW | 1.8MW | 2MW in 2013 | 2014 |
| KANIR | 0.18MW |  |  |

-A solar project of 10MW;

to third parties is forbidden without prior written approval
ny duplication or transmission
the property of Tractebel Engineering S.A. A
This document is

* * *

-Extension of the wind farm of 6 MW;
-A combined cycle of 60MW after 2014;

-A combined cycle of 60MW after 2014;
-The second phase of the projects of the OMVG.

-The second phase of the projects of the OMVG.
Guinea Bissau

Guinea Bissau

• Decided projects:
-The installed capacity at this moment is of approximately 5.6 MW. But the

-The installed capacity at this moment is of approximately 5.6 MW. But the
capacity available uninterrupted is of 5 MW (2.5 MW EAGB and 2.5 MW of
hiring);
-2 groups of 2.5MW financed by the World Bank and installed in 2012.

-2 groups of 2.5MW financed by the World Bank and installed in 2012.
Regarding the commissioning of these units, the leasing agreements of
2.5MW will be broken;
-Financing of 15 MW HFO for the town of Bissau supported by the UEMOA

-Financing of 15 MW HFO for the town of Bissau supported by the UEMOA
and the BOAD. Envisaged in several stages of 5 MW between 2012 and 2014;
-Rehabilitation of the power plant of EAGB in Bissau (2MW);

-Rehabilitation of the power plant of EAGB in Bissau (2MW);
-Rehabilitation of the power plant of Bafatà (5MW);

-Commissioning of the power plant of Buba (5MW);
-Through the OMVG, Guinea Bissau should benefit from 8% of power from

-Rehabilitation of the power plant of Bafatà (5MW);
-Commissioning of the power plant of Buba (5MW);

-Through the OMVG, Guinea Bissau should benefit from 8% of power from
the hydroelectric plant of Sambangalou in 2017, that is 10 MW;
-It is supposed that when the means of production become sufficient, the self-

-It is supposed that when the means of production become sufficient, the selfproducers will stop using their own means of production.
Candidates projects

• Candidates projects
-Power plant HFO of 55MW;

-Power plant HFO of 55MW;
-Saltinho, OMVG phase 2: 20MW.

-Saltinho, OMVG phase 2: 20MW.
Guinea

Guinea

• Decided projects:
-106 MW with the project of thermal plant of Manéah running on HFO. The

-106 MW with the project of thermal plant of Manéah running on HFO. The
commissioning is supposed to happen in 2014 and 2015;
-Commissioning of additional 100MW at Tombo plant;

-Commissioning of additional 100MW at Tombo plant;
-The hydroelectric run-of-river plant of Kaléta which will include three units

-The hydroelectric run-of-river plant of Kaléta which will include three units
of 80 MW and will produce on average 946 GWh per year.
-The rehabilitation of the thermal and hydroelectric units of Guinea;

-The rehabilitation of the thermal and hydroelectric units of Guinea;
-Through the OMVG, Guinea should benefit from 40% of power from the

• The site of Poudaldé on the Cogan River close to Tiopo is under feasibility
study. It is planned for 2017. Its installed capacity is of 90 MW for a
producible of 350 GWh.
• Finally, the Grand-Kinkon project has an installed capacity of 291 MW

• Finally, the Grand-Kinkon project has an installed capacity of 291 MW
for an annual producible of 735 GWh and an estimated cost of 298M$

-In addition to the second phases of the OMVS and OMVG projects, the sites
mentioned below are also considered in Guinea.
• The site of Souapiti presents an installable power of 515 MW and is

-Through the OMVG, Guinea should benefit from 40% of power from the
hydroelectric plant of Sambangalou in 2017, i.e. 51 MW.
Candidates projects:

to third parties is forbidden without prior written approval
ny duplication or transmission
the property of Tractebel Engineering S.A. A
This document is

* * *

The list of projects is presented hereafter:

| Site | Localization | Capacity\[MW\] | Annual Producible\[GWh\] |
| --- | --- | --- | --- |
| Souapiti | Maritime Guinea | 515 | 2518 |
| Amaria | 300 | 1435 |  |
| Poudadlé | 90 | 350 |  |
| Tiopo | 120 | 590 |  |
| Grand Kinkon | 291 | 735 |  |
| Kassa B | Mid-Guinea | 135 | 528 |
| Kouya | 86 | 334 |  |
| Bonkon-Diaria | 174 | 451 |  |
| Fetore | 124 | 322 |  |
| Lafou | 98 | 255 |  |
| Kouravel | 135 | 350 |  |
| Fomi | Upper Guinea | 90 | 374 |
| Diareguela | 72 | 400 |  |
| Frankonédou | 36 | 173 |  |
| Kogbédou | 14 | 96 |  |
| Morisanako | 100 | 523 |  |
| Nzébéla | Forested Guinea | 48 | 225 |
| Gozoguézia | 48 | 259 |  |

Table 29 - Hydroelectric sites under consideration in Guinea except OMVS/OMVG

-In addition, the connection of the production units of the isolated centers from
Nzerekore (3MW), Kankan (3MW) and Faranah (1.5 MW) is planned for
2016 with the interconnection projects of CLSG and Guinea-Mali.
Sierra Leone

• Candidates projects:
-Extension of the Bumbuna dam by phase 2:

-Extension of the Bumbuna dam by phase 2:
• Addition of 350 MW thanks to the Yiben dam, envisaged upstream in

• Phase 2:80 MW;
• Phase 3:85.5 MW.

• Phase 3:85.5 MW.
A project of power plant of 100 MW using the biomass as fuel;

-The addition of a new dam upstream of the current dam of Goma and the
installation of additional turbines for a total of 6 MW envisaged in 2015;
-New hydroelectric dam of Benkongor with 3 possible phases:

• Addition of 350 MW thanks to the Yiben dam, envisaged upstream in
2017;
The addition of a new dam upstream of the current dam of Goma and the

-A project of solar power plant of 5 MW;
-The hydroelectric installations mentioned in the following table are also

-The hydroelectric installations mentioned in the following table are also
considered in Sierra Leone.

-New hydroelectric dam of Benkongor with 3 possible phases:
• Phase 1:34.8 MW;

to third parties is forbidden without prior written approval
ny duplication or transmission
the property of Tractebel Engineering S.A. A
This document is

* * *

| Site | Capacity\[MW\] | Annual producible\[GWh\] |
| --- | --- | --- |
| Kuse2 | 91.8 | 679.7 |
| Kambatibo | 52.5 | 268.5 |
| Bitmai1 | 52.5 | 268 |
| Bitmai2 | 36.6 | 249.5 |
| ManoTo rivet | 180 | 795 |

Table 30 - Hydroelectric sites under consideration in Sierra Leone

For the site located on the Mano River on the border with Liberia, an equal division
of the power and the producible between the two countries is planned. The total
necessary investment is estimated to 473 M$.

Liberia

• Decided projects:
-10 MW of high-speed diesel groups (10 x 1MW) running on DDO on the site

-10 MW of high-speed diesel groups (10 x 1MW) running on DDO on the site
of Bushrod. The commissioning is envisaged in 2011;
-10 MW of medium-speed diesel groups (2 x 5MW) running on HFO on the

-10 MW of medium-speed diesel groups (2 x 5MW) running on HFO on the
site of Bushrod. The commissioning is envisaged in 2013;
-The rehabilitation of the hydroelectric installation of Mount Coffee (66 MW

-The rehabilitation of the hydroelectric installation of Mount Coffee (66 MW
could be available in 2014).
Candidates projects:

• Candidates projects:
-The Buchanan project of 35 MW (2 x 17.5 MW) located in Kakata. The

-The Buchanan project of 35 MW (2 x 17.5 MW) located in Kakata. The
commissioning is envisaged in 2013;
-30 MW of medium-speed diesel groups (6 x 5MW) running on HFO on the

-30 MW of medium-speed diesel groups (6 x 5MW) running on HFO on the
site of Bushrod. The commissioning is envisaged in 2015;
-The development of the St Paul River with the creation of the SPRA (Saint

-The development of the St Paul River with the creation of the SPRA (Saint
Paul River Authority) with the hydroelectric sites of
• Saint Paul - 1B: 78 MW and 512 GWh of annual producible;

-The construction of an additional tank (“Ultimate” Via Storage) on the Saint
Paul River upstream of the above mentioned sites. 132 MW could be
produced locally by the V-1 power plant thanks to this tank. Moreover, the
construction of a channel connecting it with the tank Via of Mount Coffee
would make it possible to increase the capacities of the hydroelectric plants
located downstream in the following proportions:
• Mount Coffee: possible addition of 66 MW;

• Saint Paul - 2: possible addition of 100 MW.

• Saint Paul - 2:120 MW and 788 GWh of annual producible.
These sites could be commissioned by 2018;

• Mount Coffee: possible addition of 66 MW;
• Saint Paul - 1B: possible addition of 65 MW;

to third parties is forbidden without prior written approval
ny duplication or transmission
the property of Tractebel Engineering S.A. A
This document is

* * *

-A hydroelectric dam of 225 MW on the Cavally River at the border with Ivory
Coast with an annual producible of 1200 GWh. This site would also be shared
for a total value of 50% per country;
-Hydroelectric sites identified on the rivers Lofa (total of 29 MW), Holy John

-Hydroelectric sites identified on the rivers Lofa (total of 29 MW), Holy John
(total of 67 MW) and Cestos (total of 41 MW).
Mali

Mali

• Decided projects:
-60 MW of the BID project (6 diesel groups of 10 MW each) running on HFO

-60 MW of the BID project (6 diesel groups of 10 MW each) running on HFO
in Balingué. 40 MW have already been commissioned in 2010. The
commissioning of the 20 MW remaining is envisaged in 2011;
-92 MW through the IP Albatross thanks to diesels groups running on HFO in

-92 MW through the IP Albatross thanks to diesels groups running on HFO in
the mining zone of Kayes. The commissioning is envisaged in 2012;
-A combined cycle of 30 MW of the BOOT project on the site of

-A combined cycle of 30 MW of the BOOT project on the site of
Noumoubougou (15MW guaranteed - commissioning in 2012);
-The hydroelectric project of installation of Félou carried out within the

-The hydroelectric project of installation of Félou carried out within the
framework of the OMVS. The share allocated to Mali is of 45%, or 27MW.
Construction is undergoing and the commissioning is envisaged in 2013;
-The hydroelectric project of Gouina carried out within the framework of the

-The hydroelectric project of Gouina carried out within the framework of the
OMVS. The share allocated to Mali is 45%, or 63MW. The commissioning is
planned for 2017;
-Connection with the interconnected network of isolated diesel groups for a

-Connection with the interconnected network of isolated diesel groups for a
total of 30.4 MW in the horizon of the study;
-A 10 MW solar project in Mopti is installed in 2012 and connected to the

-A 10 MW solar project in Mopti is installed in 2012 and connected to the
interconnected network in 2019.
-A project of combined cycle of 400 MW envisaged with Aboadze (Ghana) by

-A project of combined cycle of 400 MW envisaged with Aboadze (Ghana) by
the Emergency and security supply plan of Electric Energy of the WAPP. A
part of its energy should be importe by Mali.
Candidates projects:

• Candidates projects:
-The hydroelectric project of installation to the Sotuba 2 (6 MW). The

-The hydroelectric project of installation to the Sotuba 2 (6 MW). The
commissioning is envisaged in 2014;
-The agro-industrial project of the sugar company of Markala (SoSumar) will

-The agro-industrial project of the sugar company of Markala (SoSumar) will
contain a power plant of cogeneration from which 3MW will be extra and
transferred to the interconnected network. The commissioning is envisaged in
2014;
-The project of a small hybrid power plant for a total of 0.75MW (0.25 solar +

-A PV solar project of 20 MW to be installed as from 2013;
-The hydraulic project of Taoussa on the Niger River close to WAGP, mainly

-The hydroelectric project of installation to the current of Kenié (42 MW).
The commissioning is envisaged in 2015;
-A combined cycle of 150 MW is planned by the Emergency and Security

-The project of a small hybrid power plant for a total of 0.75MW (0.25 solar +
0.5 diesel) with Ouelessebougou in 2016;
-The hydroelectric project of installation to the current of Kenié (42 MW).

-The hydraulic project of Taoussa on the Niger River close to WAGP, mainly
dedicated to agriculture with a supplement of hydroelectricity of 25 MW;
-The project of hydroelectric plant of 10 MW (3 Kaplan turbines) in Markala

-Extension of the PV solar Mopti of 50 MW which will be connected to the
interconnected network;
-A PV solar project of 20 MW to be installed as from 2013;

to third parties is forbidden without prior written approval
ny duplication or transmission
the property of Tractebel Engineering S.A. A
This document is

* * *

-Within the framework of the projects of the OMVS, Mali should benefit from
part of the production of the Guinean sites of Koukoutamba (281MW, 858
GWh), Boureya (160 MW, 717 GWh) and Balassa (181 MW, 470 GWh) all
three located on the Bafing;
-In a more remote horizon, the OMVS projects of Gourbassi (21 MW, 104

-In a more remote horizon, the OMVS projects of Gourbassi (21 MW, 104
GWh) and Badoumbe (70 MW, 410 GWh), then of Bindougou (50 MW, 289
GWh) and Moussala (30MW, 175GWh) could also be implemented in Mali.
Ivory Coast

Ivory Coast

• Decided projects:
-Addition of 222 MW on the site of independent producer CIPREL which will

-Addition of 222 MW on the site of independent producer CIPREL which will
form a combined cycle with the gas turbine of 111 MW commissioned in
2010\. The commissioning of the new gas turbine is envisaged in July 2012
and that of the steam turbine in July 2013;
-Emergency addition of an extra 250 MW (total= 450MW) on the site of

-Emergency addition of an extra 250 MW (total= 450MW) on the site of
CIPREL or Vridi thanks to a new gas turbine and a new steam turbine in
2012;
-A combined cycle of 450 MW (2 gas turbines and a steam turbine of 150 MW

-A combined cycle of 450 MW (2 gas turbines and a steam turbine of 150 MW
each) on the site of Abbata. The commissionings are envisaged in 2014 (1st
gas turbine), 2015 (2nd gas turbine) and 2016 (steam turbine);
-A project of combined cycle of 400 MW envisaged with Aboadze (Ghana) by

-A project of combined cycle of 400 MW envisaged with Aboadze (Ghana) by
the Emergency and security supply plan of Electric Energy of the WAPP. A
part of its energy should be imported by Ivory Coast.
Candidates projects:

• Candidates projects:
-The project of 270 MW of the Soubré dam. The commissioning is envisaged

-The project of 270 MW of the Soubré dam. The commissioning is envisaged
in 2018;
-A combined cycle of 450 MW (2 gas turbines and a steam turbine of 150 MW

-A combined cycle of 450 MW (2 gas turbines and a steam turbine of 150 MW
each one) on the site of Bassam which will constitute the 5th thermal plant of
Abidjan. The commissionings would be envisaged in 2020 (1st gas turbine),
2023 (2nd gas turbine) and 2025 (steam turbine);
-The capacities of the hydroelectric sites are indexed in the table below:

For the site of Tiboto a distribution of 50% for the Ivory Coast and 50% for
Liberia can be assumed within sight of the more or less equal distribution of the
basin of the Cavally river between the two countries.

Table 31 - Hydroelectric installations under consideration in Ivory Coast

| Basins | Sites | Capacity\[MW\] | Annual producible\[GWh\] |
| --- | --- | --- | --- |
| SASSANDRA | Louga | 280 | 1.330 |
| Gribo Popoli | 112 | 515 |  |
| Boutoubre | 156 | 785 |  |
| BANDAMAN | Tiassalé | 51 | 215 |
| CAVALLY | Tiboto | 225 | 1.200 |
| COMOE | Aboisso-Comoe | 90 | 392 |

Ghana

to third parties is forbidden without prior written approval
ny duplication or transmission
the property of Tractebel Engineering S.A. A
This document is

* * *

• Decided projects:
-Phase 1 of power plant T3 of Aboadze (in construction), which will consist of

-Phase 1 of power plant T3 of Aboadze (in construction), which will consist of
a combined cycle of 120 MW. Its commissioning is planned for 2012;
-A second gas turbine of 110MW on the site of Tema T1 with commissioning

-A second gas turbine of 110MW on the site of Tema T1 with commissioning
envisaged in 2012. The addition of a steam turbine of 110 MW is envisaged in
2015 to create a combined cycle of a total of 330 MW;
-Hydroelectric dam of 400 MW in Bui on the Black Volta with an annual

-Hydroelectric dam of 400 MW in Bui on the Black Volta with an annual
producible of 1000 GWh. The commissioning is planned for mid 2013;
-Two gas turbines of 110 MW each one envisaged in Domini by BTPP (central

-Two gas turbines of 110 MW each one envisaged in Domini by BTPP (central
Domini T1) in order to benefit from the offshore gas resources discovered.
Their commissioning is envisaged in 2013;
-Addition of a steam turbine of 110 MW on the power plant of Aboadze T2 to

-Addition of a steam turbine of 110 MW on the power plant of Aboadze T2 to
pass to a combined cycle of 330 MW in total. The commissioning is
envisaged in 2014;
-A project of combined cycle of 400 MW envisaged with Aboadze (T4) by the

-A project of combined cycle of 400 MW envisaged with Aboadze (T4) by the
Emergency and security supply plan of Electric Energy of the WAPP.
-2x5MW solar PV in 2012 and 2013;

-2x5MW solar PV in 2012 and 2013;
-Wind: 50 MW in 2014 and 100 MW in 2015;

-Wind: 50 MW in 2014 and 100 MW in 2015;
-A project of combined cycle of 450 MW (2 gas turbines of 150 MW each one

-A project of combined cycle of 450 MW (2 gas turbines of 150 MW each one
and a steam turbine of 150 MW) on the site of Maria Gléta in Benin decided
by the Emergency and Security supply plan of Electric Energy supply of the
WAPP. A part should be dedicated to the Ghana.
Candidates projects:

• Candidates projects:
-Phase 2 of the power plant of Aboadze T3 with similar characteristics to

-Phase 2 of the power plant of Aboadze T3 with similar characteristics to
phase 1 described previously. The commissioning is envisaged in 2016;
-GT on barge: 2x50 MW;

-GT on barge: 2x50 MW;
-SAP project of CC 2x163.6 MW;

-SAP project of CC 2x163.6 MW;
-The power plant of Cempower on the Tema T2 site initially made up of 2 gas

-The power plant of Cempower on the Tema T2 site initially made up of 2 gas
turbines of 110 MW to which a steam turbine of 110 MW will be added to
create a combined cycle of 330 MW;
-Addition of a steam turbine of 110 MW to the power plant of Domini T1 by

-Addition of a steam turbine of 110 MW to the power plant of Domini T1 by
BTPP to create a combined cycle of a total of 330 MW;
-5 hydroelectric sites at the stage of feasibility studies, led by the VRA (Juale,

-5 hydroelectric sites at the stage of feasibility studies, led by the VRA (Juale,
Pwalugu, Kulpawn, Daboya) and the ministry for energy (Hemang):

to third parties is forbidden without prior written approval
ny duplication or transmission
the property of Tractebel Engineering S.A. A
This document is

* * *

| Site | Capacity\[MW\] | Annual producible\[GWh\] |
| --- | --- | --- |
| Juale | 87 | 405 |
| Pwalugu | 48 | 184 |
| Kulpawn | 36 | 166 |
| Daboya | 43 | 194 |
| Hemang | 93 | 340 |

Table 32 - Hydroelectric sites under consideration in Ghana

There also is a project of dam with hydroelectric plant of 60 MW (3 Kaplan
turbines of 20MW) at the border with Burkina Faso on the site of Noumbiel (also
called Koulbi in Ghana) on the Black Volta. The total annual producible is
estimated to 203 GWh with a distribution of 80% of the energy produced for
Burkina and 20% for Ghana.

Togo

The sector of electricity in Togo and Benin is governed by the International
agreement and Benino-Togolese Codes electricity signed between the 2 states in
1968 and creating a community of interest between the 2 countries in the field of
electrical energy.

This code conferred to the Electric Community of Benin the monopoly of the
production, transport and the imports/exports of electrical energy on the entire
territory of the two states.

Nevertheless, the International Agreement and Benino-Togolese Code signed in
1968 were revised in 2003. It is hence the clauses of the new agreement and Code of
2003 that are now in force. According to the clauses of this new agreement and
revised Benino-Togolese Code of 2003, the CEB does not have the monopoly of the
electrical production anymore. The segment of the electrical production is opened to
the independent producers but the CEB remains the single purchaser of their
production everywhere where their network is present.

• Decided projects:
-The project of 147 MW Adjarala dam with an annual producible of 366 GWh.

-A wind project of 20 MW to be set up with a guaranteed annual energy of 40
GWh whose commissioning is envisaged in 2013;
-100 MW of thermal production with a guaranteed annual energy of 350 GWh

-A project of combined cycle of 450 MW (2 gas turbines of 150 MW each one
and a steam turbine of 150 MW) on the site of Maria Gléta in Benin decided
by the Emergency and Security supply plan of Electric Energy supply of the
WAPP. A part should be dedicated to the Togo.
Candidates projects:

-100 MW of thermal production with a guaranteed annual energy of 350 GWh
in 2013 (commissioning) and of 700 GWh as from 2014;
-A solar project of 5 MW of the CEB with a guaranteed annual energy of 10

to third parties is forbidden without prior written approval
ny duplication or transmission
the property of Tractebel Engineering S.A. A
This document is

* * *

-A project of dam with hydroelectric plant of 50 MW in Tététou on the Mono
River which would be located between the Nangbeto and Adjarala dams with
an annual producible of 148 GWh. A feasibility study was carried out in 1984.
Benin

Benin

• Decided projects:
-The project of 147 MW Adjarala dam (Togo) with an annual producible of

-The project of 147 MW Adjarala dam (Togo) with an annual producible of
366 GWh that should be shared between Togo and Benin.
-80 MW on the site of Maria Gleta in Cotonou. The commissioning is

-80 MW on the site of Maria Gleta in Cotonou. The commissioning is
envisaged in 2011;
-A project of combined cycle of 450 MW (2 gas turbines of 150 MW each one

-A project of combined cycle of 450 MW (2 gas turbines of 150 MW each one
and a steam turbine of 150 MW) on the site of Maria Gléta in Cotonou
decided by the Emergency and Security supply plan of Electric Energy supply
of the WAPP. The power plant should be operational in 2014.
Candidates projects:

• Candidates projects:
-A 20 MW solar project to be set up with a guaranteed annual energy of 40

-A 20 MW solar project to be set up with a guaranteed annual energy of 40
GWh whose commissioning is envisaged in 2012;
-A 5 MW solar project of the CEB with a guaranteed annual energy of 10

-A 5 MW solar project of the CEB with a guaranteed annual energy of 10
GWh whose commissioning is envisaged in 2015;
-A solar project of 5 MW financed by the AFD in the North-East of Benin.

-A solar project of 5 MW financed by the AFD in the North-East of Benin.
(commissioning supposed: 2014);
-A project of dam with hydroelectric plant of 160 MW in Kétou on the Ouémé

-A project of dam with hydroelectric plant of 160 MW in Kétou on the Ouémé
River with an annual producible estimated to 490 GWh. A feasibility study
was carried out in 1992.
Burkina Faso

Burkina Faso

• Decided projects:
-18 MW running on HFO and forming the first phase of the power plant of

-18 MW running on HFO and forming the first phase of the power plant of
Komsilga. The commissioning is envisaged in 2011;
-37.5 MW (3 diesel groups of 12.5 MW running on HFO and forming the 2nd

-37.5 MW (3 diesel groups of 12.5 MW running on HFO and forming the 2nd
phase of the power plant of Komsilga. The commissioning is envisaged in
2011;
-36 MW (2 diesel groups of 18 MW) running on HFO which will form the 3rd

-36 MW (2 diesel groups of 18 MW) running on HFO which will form the 3rd
phase of the power plant of Komsilga (total 90MW). The commissioning is
envisaged in 2013;
-20 MW (2 diesel groups of 10 MW running on HFO and forming the 2nd

• Candidates projects:
-A solar project of 20 MW of which 16 MW would be dedicated to the mining

-The connection of isolated centers between 2011 and 2013 for a total of 13.5
MW installed and 9.5 MW available;

-20 MW (2 diesel groups of 10 MW running on HFO and forming the 2nd
phase of the power plant of Sore 2. The commissioning is envisaged in 2012.
-A project of combined cycle of 400 MW envisaged with Aboadze (Ghana) by

to third parties is forbidden without prior written approval
ny duplication or transmission
the property of Tractebel Engineering S.A. A
This document is

* * *

-A project of dam with hydroelectric plant of 60 MW (3 Kaplan turbines of 20
MW) at the border with Ghana on the site of Noumbiel (called Koulbi in
Ghana) on the river Mouhoun (Black Volta). The total annual producible
estimated to 203 GWh with a distribution of 80% of the energy produced for
Burkina and 20% for Ghana;
-A project of dam with hydroelectric plant of 12 MW (3 turbines of 4MW) in

-A project of dam with hydroelectric plant of 12 MW (3 turbines of 4MW) in
Bougouriba with producible of 30 GWh;
-A project of dam with hydroelectric plant of 14 MW (2 Kaplan turbines of

-A project of dam with hydroelectric plant of 14 MW (2 Kaplan turbines of
7MW) to Bagré-downstream with an average annual producible of 37.3 GWh.
Niger

Niger

• Decided projects:
-In 2011, seven 2.2 MW diesel units each will be installed with the power plant

-In 2011, seven 2.2 MW diesel units each will be installed with the power plant
of Niamey 2, to replace the old diesel units;
-In 2012,2 units of 2MW each will be installed in Maradi and 2 others of 2

-In 2012,2 units of 2MW each will be installed in Maradi and 2 others of 2
MW will be installed in Zinder, in Centre-East Niger area;
-In the river area, an additional diesel power of 70MW will be installed in

-In the river area, an additional diesel power of 70MW will be installed in
Niamey in 2013.

-In the River area, the Kandadji dam will be completed by 2015. This 130 MW
dam should bring 629 GWh annually to Niger;
Candidates projects:

• Candidates projects:
-The coal center of Salkadamna would add up 200 MW. This power plant

-The coal center of Salkadamna would add up 200 MW. This power plant
would be localized between the River, Centre-East and Northern areas, close
to a coal deposit and would be built by sections of 50MW between 2015 and
2016;
-In the River area, a 30 MW wind farm is planned in 2014. The site has still to

-In the River area, a 30 MW wind farm is planned in 2014. The site has still to
be defined;
-In the River area, a thermal solar power plant of 50 MW is planned for 2014.

-In the River area, a thermal solar power plant of 50 MW is planned for 2014.
The site still has to be defined;
-In the Centre-East area, Zinder, a combined cycle of 60 MW is expected in

-In the Centre-East area, Zinder, a combined cycle of 60 MW is expected in
2013;
-Other hydro units are mentioned in the River area:

-FGN phase 1:1408 MW of which 1055 MW were commissioned in 2007.
There remain 353 MW planned for 2011;
-NIPP: 2599 MW planned for 2011;

-A project of combined cycle of 450 MW (2 gas turbines of 150 MW each one
and a steam turbine of 150 MW) on the site of Maria Gléta in Benin decided
by the Emergency and Security supply plan of Electric Energy supply of the
WAPP. A part should be dedicated to Nigeria.
-FGN phase 1:1408 MW of which 1055 MW were commissioned in 2007.

Nigeria

-FGN phase 2:2148 MW envisaged including 696 MW for 2012 and 1452 MW
for 2013.

• Gambou for 122.5 MW;
• Dyodonga for 26 MW.

-NIPP: 2599 MW planned for 2011;
-FGN phase 2:2148 MW envisaged including 696 MW for 2012 and 1452 MW

-Other hydro units are mentioned in the River area:

• Dyodonga for 26 MW.
Nigeria

to third parties is forbidden without prior written approval
ny duplication or transmission
the property of Tractebel Engineering S.A. A
This document is

* * *

For all that, the oil companies envisaged the following investments:

-The power plant of Afam 6, by Shell: 5 units of 150 MW in 2012;
-The power plant of Bonny, by Mobil: 3 units of 130 MW in 2012;

-The power plant of Bonny, by Mobil: 3 units of 130 MW in 2012;
-The Chevron Texaco power plant with 3 units of 250 MW by 2012;

-The Chevron Texaco power plant with 3 units of 250 MW by 2012;
-The power plant of TotalFinaElf with 4 units of 125 MW by 2012.

-The power plant of TotalFinaElf with 4 units of 125 MW by 2012.
Moreover, some IPP are expected:

Moreover, some IPP are expected:

-Alscon with 6 units of 90 MW by 2012;
-Power plant IBOM Power 2 with 500 MW in 2012.

-Power plant IBOM Power 2 with 500 MW in 2012.
Candidates projects:

• Candidates projects:
Important hydroelectric projects are considered in Nigeria:

Important hydroelectric projects are considered in Nigeria:

-The rehabilitation of Kainji;
-The project of Zungeru (700MW);

-The project of Zungeru (700MW);
-The project of Mambilla (8x325MW).

-The project of Mambilla (8x325MW).
Some IPP are also expected of which

Some IPP are also expected of which

-ICS Power: 6 units of 100 MW in 2015;
-WESTCOM power plant of 500 MW in 2015;

-WESTCOM power plant of 500 MW in 2015;
-The Farm Electric power plant of 150 MW in 2015;

-The Farm Electric power plant of 150 MW in 2015;
-The Supertek power plant of 1000 MW in 2017;

-The Supertek power plant of 1000 MW in 2017;
-The Ethiope power plant of 2800 MW in 2017.

-The Ethiope power plant of 2800 MW in 2017.
Comments concerning the OMVS

Comments concerning the OMVS

The OMVS is an organization having for purpose to organize the actions of four
countries for the development of the Senegal River and its basin. Its members are
Guinea, Mali, Mauritania and Senegal.

The first realization of the OMVS is the Manantali dam located in Mali on the
Bafing (affluent of Senegal) whose construction was completed in 1988. A
hydroelectric plant of 205MW (4 groups of 41 MW) was installed offering an annual
producible of 800GWh. The production of the site was made available for 3 of the
countries of the OMVS thanks to a 225 kV interconnection line from Bamako to
Dakar along the border of Senegal with Mauritania.

The OMVS considers many projects with horizons going from short to the long
term. They are summarized in the following table:

to third parties is forbidden without prior written approval
ny duplication or transmission
the property of Tractebel Engineering S.A. A
This document is

* * *

| River | Site | Country | Capacity\[MW\] | Annual producible\[GWh\] | Estimated cost\[M$\] | Status | Commissioning supposed |
| --- | --- | --- | --- | --- | --- | --- | --- |
| Senegal | Félou | Mali | 60 | 350 | 170 | EC. | 2013 |
| Gouina | Mali | 140 | 589 | 329 | APD | 2017 |  |
| Bafing | Koukoutamba | Guinea | 281 | 858 | 440 | APD | CT |
| Boureya | Guinea | 160 | 717 | 373 | APS | CT |  |
| Balassa | Guinea | 181 | 470 | 171 | F | CT |  |
| Bindougou | Mali | 50 | 289 |  | PF | MT |  |
| Diaoya | Guinea | 149 | 581 | 332 | PF | LT |  |
| Falémé | Gourbassi | MaliSenegal | 21 | 104 |  | F | MT |
| Moussala | Mali | 30 | 175 |  | PF | MT |  |
| BakoyeTene | Badoumbe | Mali | 70 | 410 |  | F | MT |
| Tene I | Guinea | 76 | 199 | 122 | PF | LT |  |

Table 33 - hydroelectric Projects of the OMVS

EC.: In construction; APD: Detailed preliminary draft; APS: Summary preliminary
draft; F: Feasibility; PF: Pre-feasibility; CT/MT/LT: short/middle to long term.

Comments concerning the OMVG

The OMVG is an organization which aims at coordinating the actions of the four
countries concerned with the basin of The Gambia River: Senegal, Guinea, The
Gambia and Guinea Bissau. By extension, other rivers of the area are concerned by
this organization.

Up to now, the OMVG has two big projects.

The first big project is composed of two parts and is planned for 2016:

• The hydroelectric plant of Sambangalou which will include 4 units of 32 MW
and will produce on average 402 GWh per year.
A 225 kV interconnection which will cross 1677 km to connect 15 sub-stations,

The second big project is composed of four parts and is envisaged later on:

• The run-of-river power plant of Saltinho in Guinea Bissau. Of a power of 20 MW
(3 units of 6.5 MW), it will have an average producible estimated to 82 GWh.
The run-of-river power plant of Digan in Guinea. With a power of 93.3 MW, will

• The run-of-river power plant of Digan in Guinea. With a power of 93.3 MW, will
have an average producible of 242.5 GWh.
Fello-Sounga dam, in Guinea, with its two units of 41 MW. It will ensure the

• Fello-Sounga dam, in Guinea, with its two units of 41 MW. It will ensure the
annual production of 333 GWh.

• Reinforcement of the 225 kV interconnection line built at the time of the first
project. 500 new kilometers of line should be built. There will be 4 new substations. That will cost 145.4 million dollars.

to third parties is forbidden without prior written approval
ny duplication or transmission
the property of Tractebel Engineering S.A. A
This document is

* * *

2.2.5. Transmission data

The purpose of this chapter is to synthesize the data of transport which were
introduced into the optimization tool PRELE.

The decided projects have a set commissioning date. The planned projects are not
questioned but the possibility of a delay of 2 years is considered. Finally, the
projects considered are left free with optimization. In addition, investments other
than the big projects of interconnections are proposed to the optimization tool.

2.2.5.1. DECIDED PROJECTS

This section shows the decided projects for which the studies are finished and for
which the financing was or is about to be obtained.

“330kV Coastal Backbone” project

The project consists of a 330 kV axis along the coast interconnecting Ivory Coast
(Riviera), Ghana (Prestea and Volta), Togo (Lome C), Benin (Sakété) and Nigeria
(Ikeja West). 2 sections are planned to complete the 2 already existing sections

• The Volta (Ghana) - Sakété (Benin) section passing by Lome which should be
commissioned in 2013;
The Riviera (Ivory Coast) - Ghana (Prestea) section. It should be commissioned

• The Riviera (Ivory Coast) - Ghana (Prestea) section. It should be commissioned
by 2017.

OMVG project

The OMVG project includes a 225 kV interconnection simple line simple circuit
crossing Guinea, Senegal, Guinea-Bissau and The Gambia to share the hydroelectric
production of the Guinean sites. The commissioning is envisaged in 2017 but the
first phase (Linsan-Labé-Mali and Linsan-Kaolack-Tambacounda) could be finished
sooner (2015).

CLSG project (Ivory Coast - Liberia - Sierra Leone - Guinea)

Interconnection Ghana-Burkina Faso.

Please note that the 225 kV single circuit line internal to Ivory Coast which is
planned between Laboa and Ferkéssédougou supplements this project while making
it possible to close the 225 kV loop inside Ivory Coast and to secure the
interconnections towards the North.

to third parties is forbidden without prior written approval
ny duplication or transmission
the property of Tractebel Engineering S.A. A
This document is

* * *

Interconnection Ghana - Burkina Faso-Mali

This interconnection 225 kV envisages to connect the Bolgantaga (Ghana) - Bobo
Dioulasso (Burkina Faso) - Sikasso (Mali) - Bamako (Mali) substations by 2015. It
is envisaged in double circuit on the Bamako-Sikasso section. In Sikasso, a circuit
goes towards Ferkessedougou and a second continues towards Bobo Dioulasso.

2.2.5.2. PLANNED PROJECTS

This section shows projects already quite detailed and having been subject of
feasibility studies but for which complementary studies are still to be done and/or
for which part of the financing still remains to be found.

Interconnection Guinea - Mali

The project of Guinea-Mali interconnection is registered among the priority projects
identified by the Revised Master plan of the ECOWAS. It is conceived to evacuate
the production of the future hydroelectric plant of 90MW of Fomi (Guinea). The
project includes the construction of a 225 kV line between Fomi (Guinea) and
Nzérékoré (Guinea) then between Fomi (Guinea) and Bamako (Mali) and between
Fomi (Guinea) and Linsan (Guinea). It is planned for 2016.

These transmission lines will not only allow the interconnection of Guinea and Mali,
but also the interconnection between the Member States of the OMVS and with the
future line of interconnection of Ivory Coast - Liberia - Sierra Leone - Guinea
(CLSG).

Project “North-core”

The project uses again a 330 kV interconnection line between Birnin Kebbi
(Nigeria) - Bembéréké (Benin) - Niamey (Niger) - Ouagadougou (Burkina Faso).
Several variants are considered in terms of number of circuits (1 or 2) by section.
The commissioning of this line is planned in 2016.

330 kV North-South axis in Ghana

This project, although inside the network of Ghana, is an important link of the
framework of the WAPP interconnected network strongly improving the capacities
of export towards Burkina Faso. This 330 kV interconnection line connects the
station of Domini (at the border with the Ivory Coast) to the station of Bolgatanga at
the border with Burkina Faso. The commissioning of this axis is planned for 2015.

Reinforcement project of the Nigeria-Benin interconnection

This section shows various projects which are evoked in the collected documents or
during the discussions carried out during the data collection missions in the various
countries. The studies of prefeasibility of these projects were not started yet or are in
hand.

2.2.5.3. PROJECTS CONSIDERED

This project of a double circuit line between Sakété (Benin) and Omotosho is
planned (commissioning date considered: 2016).

to third parties is forbidden without prior written approval
ny duplication or transmission
the property of Tractebel Engineering S.A. A
This document is

* * *

Median backbone project

This project is considered by the CEB in its priority development projects. This
interconnection would connect Yendi (Ghana) - Kara (Togo) - Bembereke (Benin)
and Kaindji (Nigeria). It would be expected by 2020. This project could be justified
to reinforce and evacuate the power produced by the site of Kaindji towards the
northern zones of these countries.

Nevertheless this project requires to be further specified and studied in details in
particular on the following points:

• The station of Yendi in Ghana is rather remote with a relatively low load and
there is no project of extension of the 330 kV network of Ghana to connect this
161 kV sub-station. It would be more logical to extend this line to the 330 kV
axis crossing Ghana from North to South;
The other variant is to carry out the median backbone in 161kV, except for the

• The other variant is to carry out the median backbone in 161kV, except for the
Kainji-Bembereke section, which would be in 330 kV.
Interconnections Liberia – Ivory Coast

Interconnections Liberia – Ivory Coast

A coastal interconnection between Monrovia in Liberia and San Pedro in Ivory
Coast is evoked by the concerned countries. This project would allow in particular
the evacuation of the hydroelectric project of Tiboto (Cavally), at the border
between the two countries.

OMVS interconnections

Regarding the commissioning of the hydraulic site of Gouina (decided project,
commissioning estimated in 2017), it will possibly be necessary to reinforce the
225kV network towards Dakar. A loop by the interior of the country is considered
via Tambacounda which would also allow a connection with the OMVG network.

A Linsan-Manantali link is also considered to interconnect the dams in project on
the territory of Guinea: Boureya and Koukoutamba.

2.2.5.4. OTHER INVESTMENT OPTIONS

• In the same optic, a variant of this layout would consist of a line connecting
Guinea to the area of Sikasso in Mali.
The various installations under consideration for the median backbone are

• A new interconnection between Guinea and the north of Ivory Coast (Fomi-
Odienne-Boundiali-Ferkessedougou) is proposed. Such an axis would make it
possible to directly evacuate the hydroelectric energy produced in Guinea
towards the northern areas having few means of production with low operation
costs. The layout of this line will be discussed in order to limit its environmental
impact.
In the same optic, a variant of this layout would consist of a line connecting

• Finally, the reinforcement of the existing decided or planned axes is also
considered.

to third parties is forbidden without prior written approval
ny duplication or transmission
the property of Tractebel Engineering S.A. A
This document is

* * *

2.2.6. Presentation of the results

The determination of the production and transmission master plan made it possible
to find the optimal combination between the development of production parks at
regional level and the development of the regional network system to supply the
electricity demand at a minimal cost.

In this master plan, the candidate production projects were proposed as investment
options whereas the commissioning of the decided units was regarded as acquired.

As mentioned in the methodology, scenario 1 (national Master plans without
developing new interconnections) and scenario 2 (optimal regional development
without limits of transit between the countries) are initially presented hereafter.

Then, scenario 3, the reference scenario (optimal regional development taking into
account the limits of transit between the countries), is described, imposing the
decided and planned transmission project and the decided production projects and
optimizing the other projects in order to minimize the cost of the objective function.

2.3. Scenario without development of new
interconnections

This scenario proposes the evolution until 2025 of the national parks of production
as proposed in the national master plans without development of new
interconnections.

In order to take into account all the problem aspects, an alternative was considered
making it possible to study the impact of the mining projects in the energy balance
of the area of West Africa.

2.3.1. Energy mix

In terms of energy mix, the results presented hereafter are those which were
obtained in the absence of massive mining projects in Guinea, Guinea Bissau, Sierra
Leone and Liberia.

If the mining projects were implemented, the number of selected hydroelectric
projects would be more important, increasing by as much the ratio of hydroelectric
energy in the energy mix.

2.3.1.1. INSTALLED CAPACITY

Nevertheless, the principal impacts of a massive mining consumption are also
examined.

to third parties is forbidden without prior written approval
ny duplication or transmission
the property of Tractebel Engineering S.A. A
This document is

* * *

About thermal projects, the combined cycles are largely promoted, mainly when
they are fed with natural gas. Indeed, these units have a very low operation cost due
to the combined effect of a very good efficiency and a fuel at low prices.

The coal projects are also selected massively based on their economic performance
in order to cover the local loads.

Nevertheless, it is important to note that few projects using renewable sources are
selected among the investment options. Indeed, these projects are in general
expensive to install and relatively not very effective because intermittent. Other
criteria such as the profit in CO2 emissions are however favorable. The
environmental and financial aspects will be considered in a forthcoming part of the
study. Let us note however that in the countries where the gas and hydroelectric
resources are non-existent, the wind projects become competitive. It is the case in
particular of Senegal and The Gambia.

Figure 7, hereafter, presents the evolution of the regional energy mix in terms of
installed capacity working on the assumption of scenario 1 without development of
new interconnections, and in the absence of massive mining projects.

Energy mix in terms of installed capacity

In addition, the gas turbines have a low efficiency and run, in an optimum
production plan, only as peak units, even if they burn natural gas.

Figure 7 - Installed capacity by type of fuel in the scenario without development of new interconnections

The economic stacking of the units wants that the least expensive units to operate
run at maximum during all the year. Thus the hydroelectric units produce the
maximum of energy which they are able to provide according to the climatic
conditions and of the local load conditions. In the same way, the combined cycles
burning natural gas are operated in base production.

2.3.1.2. PRODUCED ENERGY

The coal projects and biomass are also used as base units.

to third parties is forbidden without prior written approval
ny duplication or transmission
the property of Tractebel Engineering S.A. A
This document is

* * *

Intermittent renewable energies as for them are used as soon as the conditions allow
it.

Figure 8 - Energy produced by type of fuel in the scenario without development of new interconnections

2.3.2. Average Marginal costs

In order to identify the areas which would need to be more strongly interconnected
with their neighbours in order to decrease their production costs, the average
marginal costs per year and per area inside the countries were calculated.

The units with a marginal cost slightly lower than the maximum are tagged in
yellow. The marginal units in these areas are regularly less expensive units like coal
(Senegal-Dakar and Niger-Salkadamna) or for which the importation from better
located areas is regularly sufficient. They have a marginal cost between 90 and 100
USD/MWh.
Then there are the areas where the marginal unit is a gas turbine running on natural

The figure hereafter represents the marginal costs in the various areas of the 14
countries of West Africa by 2020 in the scenario without new interconnections.
One finds in red the areas where the marginal cost is the highest. Without surprise,

Lastly, in the long term, the most competitive projects will already have been built,
such that projects with higher production costs would have to be commissioned,
yielding an increase of the marginal cost in the majority of the areas.
The figure hereafter represents the marginal costs in the various areas of the 14

Then there are the areas where the marginal unit is a gas turbine running on natural
gas. This case is valid for all the southern part of West Africa (in green on the chart)
where the marginal cost is between 80 and 90 USD/MWh.

to third parties is forbidden without prior written approval
ny duplication or transmission
the property of Tractebel Engineering S.A. A
This document is

* * *

Lastly, the areas where there are such hydroelectric possibilities that these units are often marginal are indicated in blue. For these sites, the marginal cost is lower than 80 USD/MWh.

to third parties is forbidden without prior written approval

ny duplication or transmission

the property of Tractebel Engineering S.A. A

This document is MP-WAPP/4NT/221291/002/00 October 2011 62/273 to third parties is forbidden without prior written approval

ny duplication or transmission Engineering S.A. A

Figure 9 - Marginal cost by area in West Africa

This document is the property of Tractebel MP-WAPP/4NT/221291/002/00 October 2011 63/273

* * *

2.4. Scenario without transit limits

This second scenario proposes an optimal development of the production park on the
scale of the area by supposing that no limit of power transit applies between the
countries all over the study period.

In order to take into account all the aspects of the problem, an alternative was
considered making it possible to study the impact of the mining projects in the
energy balance of the area of West Africa.

2.4.1. Energy mix

In terms of energy mix, the results presented hereafter are those in the absence of
massive mining projects in Guinea, Guinea Bissau, Sierra Leone and Liberia.

2.4.1.1. INSTALLED CAPACITY

In terms of investment options, the observations made within the framework of the
case without development of the interconnections remain applicable in this scenario.

The optimization carried out using the tool PRELE shows that the hydroelectric
projects are massively selected based on purely economic criterion in spite of their
particularly important capital cost because their operation cost is extremely low.

About thermal projects, the combined cycles are largely supported, mainly when
they are fed with natural gas. Indeed, these units have a very low operation cost due
to the combined effect of a very good efficiency and a low price fuel.

It is important to note that few projects using renewable sources are selected among
the options investment. Only some wind projects are selected. Indeed, these projects
are in general expensive to install and relatively not very effective because
intermittent (solar and wind). Other criteria such as the profit in CO2 emissions are
however favorable. The environmental and financial aspects will be considered in a
forthcoming part of the study.

Energy mix in terms of installed capacity

Figure 10 - Installed capacity by type of fuel in the scenario without transit limits

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

2.4.1.2. PRODUCED ENERGY

As in scenario 1, the economic stacking of the units wants that the least expensive
units to operate run at maximum during all the year. Thus the hydroelectric units
produce the maximum of energy which they are able to provide according to the
climatic conditions. In the same way, the combined cycles burning natural gas
function in base.

Nevertheless, the units burning other fuels are definitely exploited. In addition, the
gas turbines have a low efficiency and run, in an optimum plan of production, only
as peak units, even if they burn natural gas.

The coal and biomass projects are also used as base unit.

Intermittent renewable energies as for them are used as soon as the conditions allow
it.

Lastly, while comparing with the case without development of new
interconnections, it appears that the production of hydroelectricity is supported by
the possibilities of exchanges between the countries and that the use of very
expensive fossil fuels such as diesel decreases very appreciably.

Energy mix in terms of produced energy

The other countries with a strong hydroelectric potential (in particular Sierra Leone
with Bumbuna, Liberia with the St Paul project, Ivory Coast with the Soubre
project) should also contribute in an important way to the electrical production in the
area.

2.4.2. Transit on the interconnection lines

Figure 11 - Energy produced by type of fuel in the scenario without transit limits

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

On the contrary, the countries having no important hydroelectric resources and no sources of natural gas supply (as Burkina Faso for example) will naturally import electricity in a market based exclusively on the economic criteria and without transit constraints.

Consequently, the interconnection projects of Guinea with its neighbors should be capital to allow the optimal exploitation of the hydroelectric potential in the area. Let us note consequently the interest of the projects Guinea - Mali, CLSG and OMVG.

Moreover, the axes feeding the importing areas of electricity (Burkina Faso and North of Ghana) will have also a considerable role to play. Thus the axis Mali - Burkina Faso - Ghana will be a very important section for supplying the electricity demand of the Center-North of the WAPP area.

approval

to third parties is forbidden without prior written

ny duplication or transmission

This document is the property of Tractebel Engineering S.A. A

MP-WAPP/4NT/221291/002/00 October 2011 66/273

* * *

2.4.3. Scenario with mining sector

In the various countries of the zone B, many projects are considered by 2020:

• Guinea Bissau: 100 MW

• Guinea: 700 MW
Sierra Leone: 750 MW

• Sierra Leone: 750 MW
Liberia: 280 MW

• Liberia: 280 MW

These mining loads, if they were connected to the network, would considerably
change the supply/demand balance for these countries.

Thus, the load of Sierra Leone would be multiplied by four and the country, initially
exporting electricity thanks to the national hydroelectric projects, would become
importer. Hydroelectric energy could not be any more evacuated towards the areas
of the North-East because it would be consumed locally.

Consequently, additional production means will have to be implemented.

2.5. Reference scenario

In this chapter, the reference scenario is presented.

For this scenario, the decided and planned transmission projects are commissioned
at fixed date. An alternative will be carried out in order to analyze the impact of a
delay on the planned projects.

In addition, a certain number of projects other than those already considered are
proposed as investment options from 2018 on.

Nevertheless, it should be noted that the hydroelectric projects proposed in the
countries of the zone B could not reasonably be all set up by 2025 though many
appear profitable from an economic point of view. Indeed, the financial limits of the
countries, the environmental impacts, and the difficulties of accessibility will
prevent the massive development of the hydroelectricity. Moreover, numerous
projects could be entirely dedicated to the supply of the mining sector.

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

The results of this optimization are presented hereafter.

• At first, the principal results in terms about the implemented production are
presented;
The interest of the national production projects is then discussed on basis of the

• The interest of the national production projects is then discussed on basis of the
results of the reference scenario;
Among the projects which arise from the economic optimization, the projects

• Among the projects which arise from the economic optimization, the projects
answering the criteria hereafter are highlighted like potential regional projects:
-Projects whose capacity is higher than 150MW;

-Projects whose capacity is higher than 150MW;
-Projects belonging to no regional entity (OMVS, OMVG);

-Projects belonging to no regional entity (OMVS, OMVG);
-Projects located near interconnection lines in order to allow the division of the

-Projects located near interconnection lines in order to allow the division of the
capacity;
-Projects not being directly dedicated with local activities (mines).

-Projects not being directly dedicated with local activities (mines).
Finally the priority transmission projects for sharing resources between the

• Finally the priority transmission projects for sharing resources between the
countries are highlighted.

2.5.1. Implemented production means

The optimization carried out using the tool PRELE shows that the hydroelectric
projects are massively selected based on purely economic criterion in spite of their
particularly important capital cost because their operation cost is extremely low.

About thermal projects, the combined cycles are largely supported, mainly when
they are fed with natural gas. Indeed, these units have a very low operation cost due
to the combined effect of a very good efficiency and a fuel at low prices.

The coal projects are also selected based on their economic performance.

It is important to note that few projects using renewable sources are selected among
the options investment. Indeed, these projects are in general expensive to install and
relatively not very effective because intermittent (solar and wind).

Nevertheless, it is remarkable to note that wind projects are economically profitable
in the absence of subsidies in areas where few hydroelectric or gas resources are
available and where the marginal cost is high on the short term. These projects have
two advantages: they can be set up quickly and they will propose, in the short term,
a partial alternative to liquid fuels.

The figure hereafter presents the annual energy mix of the area of West Africa in
terms of installed capacity.

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

Figure 12 - Installed capacity by type of fuel in the reference scenario

In terms of produced GWh, the economic optimum wants that the least expensive
units to operate run at maximum during all the year. Thus the hydroelectric units
produce the maximum of energy which they are able to provide according to the
climatic conditions (average energy or guarantee). In the same way, the combined
cycles burning natural gas run in base production.

Nevertheless, the units burning other fuels are definitely less operated. In addition,
the gas turbines have a low efficiency and run, in an optimum production plan, only
as peak units, even if they burn natural gas.

Lastly, while comparing with the case without development of new
interconnections, it appears that the production of hydroelectricity is supported by
the exchanges possibilities between countries and that the use of very expensive
fossil fuels such as the diesel decreases very appreciably.

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

Energy mix in terms of produced energy

Figure 13 – Produced energy by type of fuel in the reference scenario

2.5.2. National production projects

2.5.2.1. SENEGAL

Supply-demand balance

The coal power plants decided for the Senegal strongly modify the energy mix of the
country. Indeed, in the absence of significant gas and hydroelectric resources,
Senegal used, until now, liquid fuels to feed the national load.
From a regional point of view, Senegal should export part of the electricity

From a regional point of view, Senegal should export part of the electricity
generated by coal plants to the neighbouring countries) as soon as these plants will
be installed.

Senegal

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

Marginal cost

The coal units allow a significant decrease of the marginal cost of Senegal.

If no new interconnection was built (national development scenario), the marginal
cost in the long term would be identical to the reference scenario since Senegal does
not count on the importation to reduce its marginal cost

Marginal Cost- Senegal

Figure 15 - Trend of marginal cost \[$/MWh\] in Senegal

National projects

In addition to the projects already decided for the country and to the regional
projects, Senegal has a certain number of national projects which could help with the
load supply at lower costs.

This section lists the candidate projects and presents their advantages within the
framework of the optimal plan of regional development

These units are important in the short term for the supply of these isolated
centers but should not be used any more when the OMVG loop is
commissioned. Indeed, the importation of energy from Guinea and the area of
Dakar would permit to reduce the marginal cost of these centers.

2. Installation of HFO units in the isolated centers of Ziguinchor and
   Tambacounda
   These units are important in the short term for the supply of these isolated

3. Installation of mobile HFO units in Tobin and in the harbour of Bel-Air
   With the coal projects in the medium term in Senegal, the mobile HFO units are
   not selected by the optimization tool. However, if the coal projects were
   delayed, the HFO units would become an interesting alternative.


approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

3. Commissioning of a wind site of 125MW from 2014 on
   From a purely economic point of view, the solar projects are not justified in the

From a purely economic point of view, the solar projects are not justified in the
area. Nevertheless, other factors are to be taken into account and in particular
the energy policy of the area. Moreover, given that wind projects have the
advantage of being set up quickly, they could be considered in case of delay in
coal projects.

4. Solar park of 7.5MW in Ziguinchor
   From a purely economic point of view, the solar projects are not justified in the

From a purely economic point of view, the solar projects are not justified in the
area. Nevertheless, other factors are to be taken into account and in particular
the energy policy of the area.

5. Construction of several diesel units of 30 to 60MW
   On the very short term, the existing and decided projects should be sufficient

On the very short term, the existing and decided projects should be sufficient
for supplying the load if fuels are available to feed the units. In the medium and
long term, alternatives to liquid fuels should be installed. Consequently, the
diesel units are not optimal from a purely economic point of view. Nevertheless
being given their low investment costs and their fast installation, they could be
planned to fill a possible delay in the other projects.

Conclusions

In conclusion, for Senegal, the development plan by 2025 should be based on the
decided coal units, allowing bringing back the marginal cost of the country to a
lower level.

In case of delay in these projects, it will be necessary to invest in units running on
HFO and diesel or wind plants, with the advantage of fast installation and low
capital cost. It is reminded however that the units using liquid fuels have a very high
operation cost and that they should not be privileged by Senegal.

After 2020, the coal option should be selected again as investment option because
the hydroelectric projects could become insufficient for the supply of the national
load.

| Name | Technology | Fuel | Commissioning | Capacity |
| --- | --- | --- | --- | --- |
| Ziguinchor | Diesel | HFO | 2012 | 2\*5MW |
| Tambacounda | Diesel | HFO | 2012 | 2\*4MW |

Table 34 - National projects for Senegal

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

2.5.2.2. THE GAMBIA

Supply-demand balance

From a regional point of view, The Gambia should import part of its electricity from
the hydroelectric sites of neighbouring countries (in particular OMVG) as soon as it
is interconnected.

In the short term, the wind potential of the country could be an interesting alternative
to fossil fuels. This technology indeed has the advantage of being able to be settingup quickly, by 2012-2014.

Let us note that in The Gambia, the marginal cost is very high in the short term. This
configuration supports the development of wind energy.

The Gambia

Figure 16 - Supply-demand balance in energy for The Gambia

Marginal cost

The marginal cost of The Gambia is very high in the short term. The investment in
wind energy makes it possible to reduce this cost slightly but it is especially the
importation which will allow The Gambia to feed the demand for electricity at lower
costs.

If no new interconnection were built (national development scenario), The Gambia
would not have any other possibility than investing in units burning liquid fuels.

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

Figure 17 - Trend of marginal cost \[$/MWh\] in The Gambia

National projects

In addition to the projects already decided for the country and to the regional
projects, The Gambia has a number of national projects which could help supplying
the load at lower costs.

This section shows the candidate projects their interest within the framework of the
optimal plan of regional development.

1. Extension of the power plant of Brikama 2x10 MW in 2013
   The extension of the power plant of Brikama is essential from 2015 on to secure

2. Extension of the power plant of Brikama 2x10 MW in 2013
   The extension of the power plant of Brikama is essential from 2015 on to secure
   the supply of the country until the interconnection of The Gambia with the
   neighbouring countries (thanks to the OMVG loop envisaged in 2017).

3. Wind project of 4MW in 2014 and its extension of 6MW after 2015

4. Wind project of 4MW in 2014 and its extension of 6MW after 2015
   The wind projects are selected by the optimization tool because they are

5. Wind project of 4MW in 2014 and its extension of 6MW after 2015
   The wind projects are selected by the optimization tool because they are
   envisaged in the short term and that they will help reducing the marginal cost of
   The Gambia, currently very high.

6. Solar project of 10MW
   From a purely economic point of view, the solar projects are not justified in the


From a purely economic point of view, the solar projects are not justified in the
area. Nevertheless, other factors are to be taken into account and in particular
the energy policy of the area.

From a purely economic point of view, it is more interesting, in the medium
term, to import electricity since countries having hydroelectric resources (in
particular thanks to the OMVG) than producing locally with liquid fuels.
Nevertheless, in case of delays in the hydroelectric projects or the construction
of the regional transmission network, The Gambia could locally produce its
electricity starting from a combined cycle running on HFO.

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

Conclusions

In conclusion, for The Gambia, the development plan by 2015 should be based on
the decided and candidate thermal units and on a wind project making it possible to
bring back the marginal cost of the country to a lower level.

By 2020 and later, The Gambia should rely on the importation from the
hydroelectric projects and in particular OMVG projects in addition to the national
projects already set up.

In case of delay in these projects, new thermal units should nevertheless be built in
The Gambia, in particular a combined cycle running on HFO. Moreover, an
important reserve in terms of thermal energy must be maintained in The Gambia in
order to mitigate a possible shortage of hydroelectric electricity (dry year) or an
unavailability of the grid.

The table below shows the principal national developments selected by the
optimization tool according to purely economic criteria and to the horizon of the
study.

| Name | Technology | Fuel | Commissioning | Capacity |
| --- | --- | --- | --- | --- |
| Brikama Extension | Diesel | HFO | 2015 | 2\*10MW |
| The Gambia Wind 1 | Wind Turbine | WIND | 2014 | 4MW |
| The Gambia Wind 2 | Wind Turbine | WIND | 2015 | 6MW |

Table 35 - National projects for The Gambia

2.5.2.3. GUINEA BISSAU

Supply-demand balance

From a regional point of view, Guinea Bissau should import part of its electricity
from the hydroelectric sites of neighbouring countries (in particular OMVG) as soon
as it is interconnected.

In the short term, Guinea Bissau should supply its load with its thermal resources.
Unfortunately, the projects in the short term are not sufficient to feed all the demand.
This is why the marginal cost is very high during the first part of the study period. In
practice, that means that part of the auto- producers will continue to feed the load
which cannot be supplied by the network.

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

Figure 18 - Supply-demand balance in energy for Guinea Bissau

Marginal cost

The marginal cost of Guinea Bissau is very high in the short term because of the
lack of production means, which is actually compensated by the auto-producers.

In the longer term, the hydroelectric projects of the OMVG in particular will help
reducing strongly the marginal cost of the area.

Marginal Cost - Guinea Bissau

Figure 19 - Trend of marginal cost \[$/MWh\] in Guinea Bissau

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

National projects

In addition to the projects already decided for the country and to the regional
projects, Guinea-Bissau has a number of national projects which could help
supplying the load at lower costs.

This section shows the candidate projects and their interest within the framework of
the optimal plan of regional development.

1. Project of an HFO power plant of 55MW around Bissau
   A new power plant running on HFO would be essential as early as possible to

A new power plant running on HFO would be essential as early as possible to
reabsorb the unserved demand. Nevertheless, considering that the feasibility
studies must still be realized and that the 30kV loop around Bissau must be built
to allow the supply of the load, the horizon 2015 seems reasonable for this
power plant.

2. Hydroelectric plant of Saltinho within the framework of the OMVG
   The hydroelectric project of Saltinho is less competitive than the other

The hydroelectric project of Saltinho is less competitive than the other
hydroelectric projects. Consequently, based on purely economic criterion, this
installation is not justified. Nevertheless, its development within the framework
of the OMVG and its proximity with the axis of transport of the OMVG gives to
this project an additional value. Moreover, it would help reducing the energy
dependence of Guinea Bissau.

Conclusions

In conclusion, for Guinea Bissau, the development plan by 2015-2017 should be
based on the decided and candidate thermal units in order to limit the quantity of
unserved energy.

By 2020 and later, Guinea Bissau should rely on the importation since the
hydroelectric projects and in particular on the OMVG projects in addition to the
national projects already set up. Among the projects of the OMVG, the installation
of Saltinho is less competitive from an economic point of view but could be justified
for other reasons (political, technical, environmental and/or financial).

In case of delay in these projects, new thermal units should nevertheless be built in
Guinea Bissau. Moreover, an important reserve in terms of thermal energy must be
maintained in Guinea Bissau in order to mitigate a possible shortage of hydroelectric
electricity (dry year) or an unavailability of the grid.

2.5.2.4.

| Name | Technology | Fuel | Commissioning | Capacity |
| --- | --- | --- | --- | --- |
| Bissau | Diesel | HFO | 2015 | 55MW |

Table 36 - National projects for Guinea Bissau

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

2.5.2.5. GUINEA

Supply-demand balance

From a regional point of view, Guinea should tend towards the export of the energy
produced on its territory with its hydroelectric resources.

Nevertheless, the installation of hydroelectric projects is relatively long and in the
short term, Guinea will have to use thermal production means to cover its load. In
the absence of production means, part of the load will be not served.

Let us note that if the interconnection lines towards the countries of zone A, having
gas resources, was suddenly commissioned before the hydroelectric projects are
developed in Guinea, the country would be slightly importing (2015-2016).

Figure 20 - Supply-demand balance in energy for Guinea

Marginal cost

The marginal cost of Guinea is very high in the short term because of the lack of
production means.

In the longer term, the hydroelectric projects of the OMVG, OMVS and the national
projects will help reducing strongly the marginal cost of the area.

If no new interconnection was built (national development scenario), the marginal
cost in the long term would be identical to the reference scenario since Guinea does
not count on the importation to reduce its marginal cost. Let us note however that
during the period 2015-2017, the reference scenario shows that the economic
optimum recommends that Guinea imports its energy from the countries with gas
resources, which is not possible in the isolated case and what explains the delay in
the resorption of unserved energy.

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

Figure 21 - Trend of marginal cost \[$/MWh\] in Guinea

National projects

Among the candidate projects for Guinea, many hydroelectric installations belong to
the projects of the OMVG and the OMVS. These projects are presented in section
2.5.3.

In addition, based on criteria defined in section 2.5, five Guinean projects were
adopted as regional projects: Souapiti, Amaria, Bonkon Diara, Grand Kinkon
and Kassa. These projects are described more precisely in section 2.5.4.

This section shows the candidate projects and their interest within the framework of
the optimal plan of regional development.

-The site of Poudaldé on the Cogan River close to Tiopo is planned for 2017.

It presents a lower price than Tiopo and is very interesting for Guinea.
-The site of Fomi is also very interesting for its cost and its localization, near

-The site of Fomi is also very interesting for its cost and its localization, near
the town of Kankan and on the 225kV axis Guinea-Mali.
-Another projects in High-Guinea, namely Kouravel is also competitive.

-Another projects in High-Guinea, namely Kouravel is also competitive.
Moreover, its localization near the town of Labé and the main 225kV axes
makes it interesting for the load supply in all the West circuit area of Guinea.

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

Conclusions

In conclusion, for Guinea, the development plan by 2015-2017 should be based on
the decided and candidate thermal units in order to limit the quantity of not served
energy.

As soon as possible, the local hydroelectric sites should nevertheless be invested in
order to reduce the marginal cost in Guinea.

Let us note that the number of projects which are justified economically is
particularly high in Guinea. They cover much more than the local load and the
energy produced by these projects is partially intended for export in the reference
scenario. It is obvious that all these projects could not be commissioned by 2025
even though it represents the economic optimum. Consequently, other aspects such
as the environmental parameters, the accessibility of the sites and the possibilities of
connection to the interconnected network will have to be taken into account in order
to select the projects which should be highlighted by the local authorities.

The table below shows the principal national developments selected by the
optimization tool according to purely economic criteria and to the horizon of the
study. The most economically interesting national hydroelectric projects should be
commissioned with priority and their development is estimated for 2018-2019. The
competitive but slightly more expensive projects have a commissioning date
estimated at 2020.

| Name | Technology | Fuel | Commissioning | Capacity |
| --- | --- | --- | --- | --- |
| Poudalde | Hydro | HYDRO | 2017 | 90MW |
| Fomi | Hydro | HYDRO | 2019 | 90MW |
| Kouravel | Hydro | HYDRO | 2021 | 135MW |

Table 37 - National projects for Guinea

2.5.2.6. SIERRA LEONE

Supply-demand balance

From a regional point of view, Sierra Leone should tend towards the export of the
energy produced on its territory being given its many hydroelectric resources.

Let us note that if the interconnection lines towards the countries of the zone A,
having gas resources, had suddenly been commissioned before the hydroelectric
projects are developed in Sierra Leone, the country would become slightly importer
(2015-2016).

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

Figure 22 - Supply-demand balance in energy for Sierra Leone

Marginal cost

In the short term, the marginal cost of Sierra Leone should increase because the
share of the electricity produced from cheap resources (Bumbuna I) will decrease.

In the longer term, the national hydroelectric projects will help reducing strongly the
marginal cost of the country.

If no new interconnection were built (national development scenario), the marginal
cost in the long term would be identical to the reference scenario since Sierra Leone
does not count on the importation to reduce its marginal cost. Let us note however
that during the period 2015-2017, the reference scenario shows that the economic
optimum recommends thin Sierra Leone imports its energy from countries with gas
resources, which is not possible in the isolated case. It explains why the marginal
cost is higher during this period.

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

National projects

Based on criteria defined in section 2.5, the Bumbuna project and the Mano River
project at the border of Sierra Leone and Liberia are adopted as regional project.
These projects are described in section 2.5.4.1.

In addition to the projects already decided for the country and to the regional
projects, Sierra Leone has a certain number of national projects which could help
supplying the load at lower costs.

This section shows the candidate projects and their interest within the framework of
the optimal plan of regional development.

1. Hydroelectric projects
   The installation of Benkongor is considered only in the long term, after the

The installation of Benkongor is considered only in the long term, after the
horizon of this study. Only phase III of Benkongor is considered in the medium
term and this installation is justified economically

The other hydroelectric projects are considered in the longer term since no
feasibility study exists. Moreover, they are not part of the development plans
described by the Ministry of Energy in its document “Sierra Leone Energy
Sector: Prospective customers & Challenges”. Lastly, the projects of
Kambatibo, Bitmai and Goma have a relatively high cost, making these projects
less competitive.

2. Project of a 100 MW biomass power plant
   From a purely economic point of view, the biomass projects are not justified in

From a purely economic point of view, the biomass projects are not justified in
the area. Nevertheless, other factors are to be taken into account and in
particular the energy policy of the area.

3. Sugar project which could produce 15MW from bagasse
   From a purely economic point of view, the biomass projects are not justified in

From a purely economic point of view, the biomass projects are not justified in
the area. However, coupled to an industrial activity, this project makes sense.

On the very short term nevertheless, it will be necessary to invest in units burning
liquid fuels to satisfy the electric demand, waiting for the deployment of the
hydroelectric sites of Bumbuna and, in the longer term, of Benkongor.

4. Project of solar power plant of 5 MW
   From a purely economic point of view, the solar projects are not justified in the

From a purely economic point of view, the solar projects are not justified in the
area. Nevertheless, other factors are to be taken into account and in particular
the energy policy of the area.

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

The table below shows the principal national developments selected by the
optimization tool according to purely economic criteria and to the horizon of the
study.

| Name | Technology | Fuel | Commissioning | Capacity |
| --- | --- | --- | --- | --- |
| BENKONGOR 3 | Hydro | HYDRO | 2018 | 85MW |

Table 38 - National projects for Sierra Leone

2.5.2.7. LIBERIA

Supply-demand balance

From a regional point of view, Liberia should tend towards the export of the energy
produced on its territory with its hydroelectric resources.

Nevertheless, the commissioning of hydroelectric projects is relatively long and, in
the short term, Liberia will have to use thermal production means to cover its load.

Figure 24 - Supply-demand balance in energy for Liberia

Marginal cost

In the short term, the marginal cost of Liberia is very high because electricity is
produced from diesels group whose operation costs are very high.

In the longer term, the national hydroelectric projects will help reducing strongly the
marginal cost of the country.

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

Figure 25 - Trend of marginal cost \[$/MWh\] in Liberia

National projects

Based on criteria defined in section 2.5, the Mano River project at the border of
Sierra Leone and Liberia is adopted as regional project. In the same way, the Tiboto
project at the border of Ivory Coast and Liberia is also highlighted at the regional
level. These projects are described in section 2.5.4.1.

This section shows the candidate projects and their interest within the framework of
the optimal plan of regional development.

1. Buchanan project of 35 MW (2 X 17.5 MW) located at Kakata
   This project, using shavings as combustible is not justified economically.

In Liberia, the most promising projects are those located on the Saint-Paul
River. The first phase of the project with the sites from Saint-Paul 1B and 2 is
fully justified on the economic plan. The second phase of Saint-Paul project
consists in an additional tank (“Ultimate” Via Storage) and is however
considered in the longer term. Moreover the impact of this tank for the
environment could prove to be a critical element. Consequently, this extension
is not considered to the horizon of the study
The other hydroelectric sites identified on the Lofa (total of 29 MW), Holy

In Liberia, the most promising projects are those located on the Saint-Paul
River. The first phase of the project with the sites from Saint-Paul 1B and 2 is
fully justified on the economic plan. The second phase of Saint-Paul project
consists in an additional tank (“Ultimate” Via Storage) and is however
considered in the longer term. Moreover the impact of this tank for the
environment could prove to be a critical element. Consequently, this extension
is not considered to the horizon of the study
The other hydroelectric sites identified on the Lofa (total of 29 MW), Holy

2. Hydroelectric projects
   In Liberia, the most promising projects are those located on the Saint-Paul

This project, using shavings as combustible is not justified economically.
Nevertheless, other factors are to be taken into account and in particular the
energy policy of the area.

is not considered to the horizon of the study
The other hydroelectric sites identified on the Lofa (total of 29 MW), Holy
John (total of 67 MW) and Cestos (total of 41 MW) rivers are as for them less
competitive from an economic point of view. However, their small size could
make the implementation of these projects easier.

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

3. 30 MW of semi-rapid diesel groups (6\*5 MW) running on HFO on the site
   of Bushrod
   The commissioning of these groups is envisaged in the medium term and it will

(6^{\*5}

The commissioning of these groups is envisaged in the medium term and it will
not be necessary if the hydroelectric projects are developed according to the
program considered. Nevertheless, any delay in the hydroelectric projects will
have to be compensated by thermal projects in order to secure the supply of
electricity.

Conclusions

The development plans for Liberia are of 2 types; hydroelectric and renewable
(biomass). In a purely economic scenario however, the renewable projects are not
competitive. On the other hand, the hydroelectric resources of the country should be
exploited as soon as possible, for the supply of the domestic load, the supply of the
mining sector if this one suddenly develops in Liberia or for exporting towards areas
without hydroelectric resources.

The table below shows the principal national developments selected by the
optimization tool according to purely economic criteria and to the horizon of the
study.

| Name | Technology | Fuel | Commissioning | Capacity |
| --- | --- | --- | --- | --- |
| SAINT-PAUL 1B | Hydro | HYDRO | 2020 | 78 MW |
| SAINT-PAUL 2 | Hydro | HYDRO | 2020 | 120 MW |

Table 39 - National projects for Liberia

2.5.2.8. MALI

Supply-demand balance

From a regional point of view, Mali should import part of its electricity from the
hydroelectric sites of neighbouring countries (in particular OMVS).

In complement, the own hydroelectric resources of the country are privileged by the
optimization tool.

Figure 26 - Supply-demand balance in energy for Mali

Mali

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

Marginal cost

The energy mix of Mali, based on hydroelectric and thermal resources, helps the
country to reach an average marginal cost in the short term, and lower than in the
other countries of zone B.

In the longer term, the hydroelectric potential of the neighbouring countries would
make it possible to reduce further this marginal cost.

If no new interconnection were built (national development scenario), the marginal
cost in the long term would be higher than in the reference scenario because Mali
should exploit thermal resources in complement of hydroelectric energy.

Marginal Cost - Mali

Figure 27 - Trend of marginal cost \[$/MWh\] in Mali

In addition to the projects already decided for the country and to the regional
projects (projects OMVS presented in section 2.5.3), Mali has a certain number of
national projects which could help supplying the load at lower costs.

This section shows the candidate projects and their interest within the framework of
the optimal plan of regional development.

1. Hydroelectric projects

From a purely economic point of view, the biomass projects are not justified in
the area. However, coupled to an industrial activity, this project makes sense.

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

3. Solar projects of Mopti and the project of a small hybrid power plant
   From a purely economic point of view, the solar projects are not justified in the
   area. Nevertheless, other factors are to be taken into account and in particular
   the energy policy of the area.

4. A combined cycle of 150MW
   This project envisaged by the Emergency plan and of Electric Safety of Energy


This project envisaged by the Emergency plan and of Electric Safety of Energy
supply of the EEEOA would not be justified if all the hydroelectric projects
under consideration in the area were carried out in the intended deadlines.
Nevertheless, any delay in the hydroelectric projects will have to be
compensated by thermal energy.

Conclusions

In conclusion, for Mali, the development plan by 2015 should be based on the
existing and decided hydroelectric and thermal units.

By 2020, Mali should rely on the regional (OMVS) and national hydroelectric
projects (Kenié) in addition to the national projects already set up.

In case of delay in these projects, it will be necessary to invest in units running on
HFO and diesel which have the advantage of being able to be commissioned more
quickly and whose capital cost is lower. Let us recall however that these units have a
higher operation cost and that they should not be privileged in Mali.

The table below shows the principal national developments selected by the
optimization tool according to purely economic criteria and to the horizon of the
study.

| Name | Technology | Fuel | Commissioning | Capacity |
| --- | --- | --- | --- | --- |
| KENIE | Hydro | HYDRO | 2016 | 42 MW |

Table 40 - National projects for Mali

2.5.2.9. IVORY COAST

Supply-demand balance

From a regional point of view, Ivory Coast should tend towards the export of part of
its electricity. Indeed, this country has at the same time important hydroelectric
resources and a gas potential to exploit.

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

Figure 28 - Supply-demand balance in energy for Ivory Coast

Marginal cost

The energy mix of Ivory Coast, based on hydroelectric and thermal resources (gas),
permits to reach a low marginal cost in the country in the short term.

If no new interconnection were built (national development scenario), the marginal
cost in the long term would be identical to the reference scenario since Ivory Coast
does not count on the importation to reduce its marginal cost.

Marginal Cost - Ivory Coast

Figure 29 - Trend of marginal cost \[$/MWh\] in Ivory Coast

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

National projects

Based on criteria defined in section 2.5, the Tiboto project at the border between
Ivory Coast and Liberia are highlighted at the regional level. In the same way, the
projects of Soubré and Botoubré are projects which could be exploited at regional
level. These projects are described in section 2.5.4.1.

In addition to the projects already decided for the country and to the regional
projects, Ivory Coast has a certain number of national projects which could help
supplying the load at lower costs.

This section shows the candidate projects and their interest within the framework of
the optimal plan of regional development.

1. Hydroelectric projects
   The hydroelectric projects

The hydroelectric projects of Aboisso-Comoé and Gribo-Popoli are
competitive from an economic point of view.
The project of Louga on the other hand is less competitive. It is thus not

The project of Louga on the other hand is less competitive. It is thus not
highlighted in the reference scenario based exclusively on economic criteria.
The project of Tiassale is also less competitive. It has nevertheless the

The project of Tiassale is also less competitive. It has nevertheless the
advantage of being smaller and the required funds with its construction could
be easier to find.

2. Combined cycle of Bassam (5th power plant of Bassam)
   This combined cycle is expected to be commissioned

This combined cycle is expected to be commissioned only after the
development of the hydroelectric potential of the country, meaning after the end
of the study period.

Conclusions

In conclusion, for Ivory Coast, the development plan at the horizon of the study
should rely on a mix of hydroelectric and thermal projects (gas). This potential
should be exploited at national but also regional level thanks to resources sharing.

2.5.2.10. GHANA

Supply-demand balance

In case of delay in the hydroelectric projects or in case of difficulties to exploit the
gas potential of the country, the exporting vocation of Ivory Coast would be
reduced. On the contrary, exploiting more massively the gas reserves would make it
possible for Ivory Coast to increase the quantity of exported electricity.

The table below shows the principal national developments selected by the
optimization tool according to purely economic criteria and to the horizon of the
study.

| Name | Technology | Fuel | Commissioning | Capacity |
| --- | --- | --- | --- | --- |
| ABOISSO COMOE | Hydro | HYDRO | 2018 | 90 MW |
| GRIBO POPOLI | Hydro | HYDRO | 2020 | 112 MW |

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

Later on however, if the projects develop massively in the countries at hydroelectric
strong potential, Ghana could import part of its electricity.

Figure 30 - Supply-demand balance in energy for Ghana

Marginal cost

The energy mix of Ghana, based on hydroelectric and thermal resources (gas), helps
the country to lower its marginal cost in the short term.

Moreover, since the structure of the production park of Ivory Coast, Ghana, Togo,
Benin and Nigeria are close (energy mix composed of hydroelectric and gas
resources) and that these countries are interconnected in 330kV via the Coastal
backbone, the trend of marginal costs in all these areas is similar.

In the longer term, it‟s hydroelectric and gas potential should make it possible to
keep reducing this marginal cost.

If no new interconnection were built (national development scenario), the marginal
cost in the long term would be identical to the reference scenario since Ghana does
not count on the importation to reduce its marginal cost, except for the period 2019-
2022 when little importation could decrease the marginal cost thanks to the
hydroelectric resources of the countries of zone B.

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

Figure 31 - Trend of marginal cost \[$/MWh\] in Ghana

National projects

In addition to the projects already decided for the country (among which the
combined cycle of Aboadze decided by the WAPP) and of the regional great
projects, Ghana has a certain number of national projects which could help
supplying the load at lower costs.

This section shows the candidate projects and their interest within the framework of
the optimal plan of regional development.

Ghana wishes to develop a policy of renewable energy which is not based
exclusively on wind power. To this purpose, five hydroelectric sites are
envisaged in Ghana: Juale, Pwalugu, Kulpawn, Daboya and Hemang.
Among these sites, those with the lowest operation costs are Juale, Pwalugu and

Among these sites, those with the lowest operation costs are Juale, Pwalugu and
Hemang. These three sites associated with a wind development policy should
permit to the country to develop renewable energy at lower costs.
2) Combined cycles projects running on gas

-The SAP Project of CC 2x163.6 MW becomes economically interesting
from 2014/2015 on.
-The combined cycle of Cempower on the site of Tema II should be

2. Combined cycles projects running on gas
   Ghana has its own gas resources in addition to a provisioning from Nigeria

-The combined cycle of Cempower on the site of Tema II should be
commissioned in 2015/2016.
-Phase II of the power plant of Aboadze T3 (120MW) whose

Ghana has its own gas resources in addition to a provisioning from Nigeria
through the WAGP pipeline.
Given the volumes of gas available and the needs for Ghana in terms of

through the WAGP pipeline.
Given the volumes of gas available and the needs for Ghana in terms of
production means, the most economic solution would consist in large combined
cycles (450MW). If such projects could not be set up at short-term, the
following projects could be realized:

-Phase II of the power plant of Aboadze T3 (120MW) whose
commissioning is envisaged in 2016 is justified fully based on economic
criterion after 2020.

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

-In the same way, the addition of a steam turbine of 110 MW to the power
plant of Domini T1 by BTPP to create a combined cycle of 330 MW is
competitive from 2020 on.
-The project of WP on barge (2x50 MW) is not competitive based on

-The project of WP on barge (2x50 MW) is not competitive based on
economic criterion;

Conclusions

In conclusion, for Ghana the development plan at the horizon of the study should
rely on a mix of hydroelectric and thermal projects (gas). Given the gas resources
available to the country and the important requirements in terms of energy, the most
economic solution would consist of the fast commissioning of large combined
cycles (450MW). If these combined cycles could not be realized in the short term,
the majority of the projects under consideration for Ghana should be commissioned
during the study period.

The table below shows the principal national developments selected by the
optimization tool according to purely economic criteria and to the horizon of the
study.

| Name | Technology | Fuel | Commissioning | Capacity |
| --- | --- | --- | --- | --- |
| SAP(DC) | Combined Cycles | NAT GAS | 2014/2015 | 2\*163.6MW |
| Domini T1(ST) | Combined Cycles | NAT GAS | 2015 | 110MW |
| Aboadze T3(DC) | Combined Cycles | NAT GAS | 2016 | 120MW |
| Pwalugu | Hydro | HYDRO | 2019 | 48MW |
| Juale | Hydro | HYDRO | 2019 | 87MW |
| Hemang | Hydro | HYDRO | 2019 | 93MW |
| Cempower(DC) | Combined Cycles | NAT GAS | 2020 | 300MW |
| Standard | Combined Cycles | NAT GAS | 2020 | 300MW |

Table 42 - National projects for Ghana

2.5.2.11. TOGO-BENIN

From a regional point of view, the Togo-Benin community should be relatively
autonomous in terms of electrical production with the arrival of Maria Gleta in 2014
thanks to an energy mix based on the hydroelectric potential and the gas resources
coming from the WAGP pipeline.

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

Figure 32 - Supply-demand balance in energy for the community Togo-Benin

Marginal cost

The interconnection of the Togo/Benin community with the neighbouring countries
allows the country to have a relatively low marginal cost in the short term thanks to
the thermal and hydroelectric resources of Nigeria and Ghana.

Moreover, since the structure of the park of production of Ivory Coast, Ghana, Togo,
Benin and Nigeria are close (energy mix composed of hydroelectric and gas
resources) and since these countries are interconnected in 330kV via the Coastal
backbone, the trend of marginal costs in all these areas is similar.

If no new interconnection were built (national development scenario), the marginal
cost in the long term would be very close to the reference scenario since the Togo-
Benin community should be relatively autonomous in terms of electrical production
in the medium and long term.

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

Figure 33 - Trend of marginal cost \[$/MWh\] in Togo/Benin

National projects

In addition to the projects already decided for the country (among which the
combined cycle of Maria Gleta decided by the WAPP) and to the great regional
projects (in particular a possible combined cycle of 450 MW with Togo - see section
2.5.4.2), Togo and Benin have a certain number of national projects which could
help supplying the load at lower costs.

This section shows the candidate projects of Togo and their interest within the
framework of the optimal plan of regional development.

1. Wind project of 20MW and solar project of 5MW
   From a purely economic point of view, the wind and solar projects are not
   justified in the area. Nevertheless, other factors are to be taken into account and
   in particular the energy policy of the area.

2. Hydroelectric project of 50MW in Tététou

3. Hydroelectric project of 50MW in Tététou
   This small hydroelectric project has a relatively high capital cost, and is
   consequently less competitive, on a purely economic level, than other projects.
   Nevertheless, from a national point of view, this project is interesting because
   its financing will be easier to find than for the great projects.

4. Solar projects for a total power of 30 MW
   From a purely economic point of view, the solar projects are not justified in the


From a purely economic point of view, the solar projects are not justified in the
area. Nevertheless, other factors are to be taken into account and in particular
the energy policy of the area.

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

2. Hydroelectric project of 160MW in Kétou
   The site is on the level of the Dogo forest near the village of Bernandingon, at

The site is on the level of the Dogo forest near the village of Bernandingon, at
approximately 150 km of Cotonou.
This project is fully justified on the economic plan and, from its size, it has a

This project is fully justified on the economic plan and, from its size, it has a
regional vocation. Nevertheless, the project as suggested in this study, namely
160MW and 490GWh could have a strong impact on the environmental level
(strategic planning of the CEB 2007-2026).
This is why other versions are also considered with a limited installed capacity

This is why other versions are also considered with a limited installed capacity
(108.8MW) but reducing the environmental impact. With a capacity of
108.8MW, the project would not really have of regional vocation any more.

Conclusions

In conclusion, for the Togo-Benin community, it is essential to exploit the gas
resources available in the two countries thanks to the WAGP pipeline. The project of
Maria-Gleta in Benin is a first stage but a second project of the same scale should be
considered in Togo.

Moreover, the hydroelectric installation of Kétou in Benin is completely competitive
from an economic point of view.

The table below shows the principal developments selected by the optimization tool,
in addition to the projects decided based on purely economic criterion and at the
horizon of the study.

| Name | Technology | Fuel | Commissioning | Capacity |
| --- | --- | --- | --- | --- |
| Kétou(Benin) | Hydro | HYDRO | 2018 | 160MW |

Table 43 - National projects for Togo and Benin

2.5.2.12. BURKINA FASO

Supply-demand balance

From a regional point of view and based exclusively on economic criterion, Burkina
Faso should be a net importer of electricity since it only has few hydroelectric
resources and no access to gas.

Thus, the commissioning, in 2012, of gas projects in Ivory Coast and in the other
southern countries and the medium-term development of hydroelectric energy in the
countries of zone B should help Burkina Faso to cover its load at lower costs.

However, if the area wished to develop the renewable energy sources, Burkina Faso
would be very a good candidate for solar energies (see section 2.7.3).

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

Figure 34 - Supply-demand balance in energy for Burkina Faso

Marginal cost

In the very short term, the marginal cost of Burkina Faso is very high because the
country does not have any alternative to liquid fuels.

The interconnection of Burkina Faso with the neighbouring countries permits to the
country to reduce its marginal cost thanks to the gas potential of the southern
countries of zone A and the hydroelectric potential of country of zone B.

Figure 35 - Trend of marginal cost \[$/MWh\] in Burkina Faso

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

National projects

In addition to the projects already decided for Burkina Faso there are a certain
number of national projects which could help supplying the load at lower costs.

This section shows the candidate projects and their interest within the framework of
the optimal plan of regional development.

1. Solar projects
   From a purely economic point of view, the solar projects are not justified in the

From a purely economic point of view, the solar projects are not justified in the
area. Nevertheless, other factors are to be taken into account and in particular
the energy policy of the area. Accordingly, Burkina Faso is one of the countries
having the greatest solar potential. Moreover, the coupling of the solar projects
to industrial activities (mining companies in particular) ensures their financing.

2. Hydroelectric projects
   Three hydroelectric projects (Noumbiel, Bougouriba, Bagré) are considered in

Three hydroelectric projects (Noumbiel, Bougouriba, Bagré) are considered in
Burkina Faso. From a purely economic point of view and looking only at the
electrical production, these 3 installations are less competitive than the other
projects. Nevertheless, from a national point of view, these projects are
interesting because their financing will be easier to gather than for the great
projects considered elsewhere in the area. Moreover, their utility for other
sectors should not be neglected.

Conclusions

In conclusion, Burkina Faso relies primarily on the importation to feed the national
demand. This is why few projects are considered for this country.

Among the projects suggested, the solar projects are not economically competitive if
no incentive for commissioning is considered. Nevertheless, if the financing can be
assured, Burkina Faso is one of the countries in the area with the best potential.

At regional level, the hydroelectric projects considered are also less competitive.
They could however be justified for other national aspects not taken into account in
this study (utility for other sectors, capacity to finance the great projects,…).

2.5.2.13. NIGER

Consequently, no candidate project is selected for Burkina Faso in addition to the
decided projects.

Lastly, the wind potential of the country could be a considerable asset in terms of
electrical production. This project indeed has the advantage of a quick possible
commissioning, by 2014.

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

Figure 36 - Supply-demand balance in energy for Niger

Marginal cost

Thanks to its interconnections with Nigeria, Niger has a relatively low marginal
cost.

If no new interconnection were built (national development scenario), the marginal
cost would be extremely similar since the country is already interconnected with
Nigeria.

Figure 37 - Trend of marginal cost \[$/MWh\] in Niger

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

National projects

Based on criteria defined in section 2.5, the coal project of Salkadamna, whose
economic interest is justified from 2022 on (even earlier if the hydroelectric projects
were delayed) is highlighted at the regional level. This project is described I nsection
2.5.4.2.

In addition to the projects already decided for the country and to the regional
projects, Niger has a certain number of national projects which could help supplying
the load at lower costs.

This section shows the candidate projects and their interest within the framework of
the optimal plan of regional development.

1. Wind farm of 30 MW
   This project is selected by the optimization tool because it is envisaged in the

This project is selected by the optimization tool because it is envisaged in the
short term and that it will help reducing the marginal cost of Niger.

2. Thermal solar power plant of 50 MW
   From a purely economic point of view, the solar projects are not justified in the

From a purely economic point of view, the solar projects are not justified in the
area. Nevertheless, other factors are to be taken into account and in particular
the energy policy of the area.

3. Combined cycle of Zinder (60 MW)
   In the medium and long term, alternatives to liquid fuels should be installed.

In the medium and long term, alternatives to liquid fuels should be installed.
Consequently, this combined cycle is not optimal from a purely economic point
of view, especially when compared to the coal power plant project of
Salkadamna.

4. Hydroelectric projects
   Other hydro units are mentioned in the River area. The Gambou project has a

Other hydro units are mentioned in the River area. The Gambou project has a
relatively high capital cost. It is consequently less competitive so that the
installation of Dyodonga (26 MW) is preferred. Moreover, this second project
is smaller and could be easier to finance.
Conclusions

Conclusions

In conclusion, in addition to the imports, Niger should rely in the medium term on
its wind and hydroelectric resources to cover its load.

The table below shows the principal national developments selected by the
optimization tool based on purely economic criterion, in addition to the decided
projects and the projects with regional vocation.

In the longer term, the country could become exporter thanks to the installation of
the coal project.

| Name | Technology | Fuel | Commissioning | Capacity |
| --- | --- | --- | --- | --- |
| River area | Wind | WIND | 2014 | 30MW |
| Dyodonga | Hydro | HYDRO | 2018 | 26MW |

Table 44 - National projects for Niger

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

2.5.2.14. NIGERIA

Supply-demand balance

From a regional point of view and based on economic criteria, Nigeria should be an
autonomous country in terms of electrical production.

Indeed, the country possesses important gas resources and a hydroelectric potential
which enable him to produce electricity at lower costs but there is such a load in the
country that all the investments that can be reasonably realized are intended for the
cover of the local load.

Figure 38 - Supply-demand balance in energy for Nigeria

Marginal cost

Thanks to its gas resources, Nigeria has a low marginal cost. Moreover, the
investment in the 2 hydroelectric sites of Mambilla and Zungeru further reduce the
marginal cost of the country.

If no new interconnection were built (national development scenario), the marginal
cost would be extremely similar since the country does not count on the importation
to reduce its marginal cost.

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

Figure 39 - Trend of marginal cost \[$/MWh\] in Nigeria

National projects

Based on criteria defined in section 2.5, the hydroelectric plants of Zungeru and
Mambilla highlighted at the regional level. These projects are described in section
2.5.4.2.

In addition to the projects already decided for the country and to the regional
projects, Nigeria has a certain number of national projects which could help
supplying the load at lower costs.

This section shows the candidate projects and their interest within the framework of
the optimal plan of regional development.

1. IPP - Gas turbines
   In Nigeria, many projects of gas turbines are already decided.

In Nigeria, many projects of gas turbines are already decided.
It becomes nevertheless essential for Nigeria to invest in base units (combined

The needs for the country are very important. Consequently, the investments which
will be carried out should be useful primarily, economically speaking, for the supply
of the local load.

It becomes nevertheless essential for Nigeria to invest in base units (combined
cycles). The passage to combined cycles belongs to the economic optimum
calculated by PRELE. Indeed, the kWh cost is lower for a combined cycle than
for a gas turbine.

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

| Name | Technology | Fuel | Commissioning | Capacity |
| --- | --- | --- | --- | --- |
| Standards | Combined cycles | NAT GAS | 2016-2021 | 1000 MW/an |

Table 45 - National projects for Nigeria

2.5.3. Production projects supported by regional entities

2.5.3.1. OMVS

OMVS is an organization dedicated to organize the actions of four countries for the
development of the Senegal River and its basin. It gathers Guinea, Mali, Mauritania
and Senegal. This organization considers many projects, in addition to those already
carried out (Manantali) and the decided ones (Félou - Gouina).

Among the projects considered Balassa is the most interesting from an economic
point of view. Moreover, its size and its location give to this project a regional
character which deserves to be supported.

In the same way, the Koukoutamba and Boureya projects have a very interesting
potential and are competitive from an economic point of view. Based on these
criteria, they could be also justified at regional level. Let us note however that they
are located on the axis Linsan-Manantali whose design could be modified because of
environmental problems.

Badoumbé project considered in the medium term is more modest in terms of size
which makes it less interesting at regional level, although it is competitive based on
economic criterion.

Lastly, the projects for which the feasibility studies were not carried out yet are
considered only in the longer term and are not considered at the horizon of the study.

| Name | Technology | Fuel | Commissioning | Capacity |
| --- | --- | --- | --- | --- |
| Balassa | Hydro | HYDRO | 2018 | 181MW |
| Koukoutamba | Hydro | HYDRO | 2018 | 281MW |
| Badoumbe | Hydro | HYDRO | 2018 | 70MW |
| Boureya | Hydro | HYDRO | 2021 | 160MW |

The projects (Saltinho, Digan and Fello-Sounga) have a small capacity. Moreover,
if the project of Digan is strongly competitive, the 2 others are less attractive from a
purely economic point of view.

OMVG is an organization which aims at coordinating the actions of the four
countries concerned with the basin of The Gambia River: Senegal, Guinea, The
Gambia and Guinea Bissau. This organization considers many projects, in addition
to those already decided (Sambangalou-Kaléta).

2.5.3.2. OMVG

| Name | Technology | Fuel | Commissioning | Capacity |
| --- | --- | --- | --- | --- |
| Digan | Hydro | HYDRO | 2018 | 93.3MW |

Table 46 - Projects OMVS at the horizon of the study

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

2.5.4. Great regional production projects

The regional projects are adopted based on purely economic criteria and according
to the reference scenario. The variants could emphasize other investments. In
addition, the financial and environmental studies will have to confirm these projects.

2.5.4.1. REGIONAL HYDROELECTRIC PROJECTS

The table hereafter presents the hydroelectric projects which arise from the reference
scenario to the regional level.

| Site | Country | Capacity\[MW\] | Energy\[GWh\] | Commissioning |
| --- | --- | --- | --- | --- |
| Souapiti | Guinée | 515 | 2518 | 2018 |
| Amaria | 300 | 1435 | 2018 |  |
| Grand Kinkon | 291 | 720 | 2018 |  |
| Kassa | 135 | 528 | 2018 |  |
| BonkonDiara | 174 | 451 | 2020 |  |
| Mano River | Liberia-Sierra Leone | 180 | 795 | 2021 |
| Bumbuna | Sierra Leone | 350 | 1245 | 2018 |
| Soubre | 270 | 1116 | 2018 |  |
| Boutoubre | Côte d'Ivoire | 156 | 785 | 2018 |
| Tiboto | 225 | 1200 | 2018 |  |
| Zungeru | Nigéria | 700 | 3019 | 2018 |
| Mambilla | 2600 | 11214 | 2018 |  |

Table 48 - Hydroelectric projects with regional vocation

Souapiti

The site of the hydroelectric Souapiti is located on the river Konkouré Its
development will enable the construction of a dam in Roller Compacted Concrete
(RCC) with a side retaining normal of 230 m, with a total capacity of the reservoir
of 17,300 hm³ , a design flow of 545m³ /s and an installed capacity of 515 MW. 225
kV transmission network of OMVG offers opportunities to evacuate the energy of
Souapiti to the countries of the region.
In addition, the dam would regulate the flow in any season for Kaleta

The site of the hydroelectric Souapiti is located on the river Konkouré Its
development will enable the construction of a dam in Roller Compacted Concrete
(RCC) with a side retaining normal of 230 m, with a total capacity of the reservoir
of 17,300 hm³ , a design flow of 545m³ /s and an installed capacity of 515 MW. 225
kV transmission network of OMVG offers opportunities to evacuate the energy of
In addition, the dam would regulate the flow in any season for Kaleta

In addition, the dam would regulate the flow in any season for Kaleta

The dam was originally foreseen with an installed capacity of 750 MW. However,
the environmental and the socio-economic issues needed the review of this project.

Amaria

Three variants are considered. The table hereafter summarizes the parameters
according to the reservoir height:

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

| Reserve | \[m\] | 60 | 80 | 100 |
| --- | --- | --- | --- | --- |
| Production(guaranteed energy) | \[GWh/an\] | 440 | 1400 | 2450 |
| Installed capacity | \[MW\] | 120 | 300 | 665 |
| Firm capacity | \[MW\] | 50 | 160 | 280 |

Table 49 - Description of the Amaria project

The initial dam had a designed normal height of 93 m for an installed capacity of
665 MW. Nevertheless, the environmental aspect and the important socio-economic
impacts required the revision of this project.

The alternative selected today consists of a dam with an installed capacity of
300MW and a guaranteed energy of 1435GWh.

The beneficiary countries of this project would be Guinea and the countries
connected to the 225kV interconnection network. Indeed, the site of Amaria is
ideally located on the layout of the OMVG line and near the evacuation axes of
CLSG and Guinea-Mali (Linsan-Fomi section).

Grand Kinkon

The Grand Kinkon project has an installed capacity of 291 MW and is very
economically interesting. With its size and its location (at only 7km of the OMVG
network), it has a regional extent which should be encouraged.

Kassa

Although its capacity is lower than 150MW, the installation of Kassa reaches
multiple goals and has consequently a true regional vocation.

Located on the Koba River at a few kilometers of the border between Guinea and
Sierra Leone, it will allow the construction of a dam for an installed capacity of 135
MW. The production of electrical energy could be evacuated through the 225 kV
line envisaged within the framework of the WAPP (line CLSG).

Bonkon-Diara

The Bonkon-Diara project offers an interesting potential of 174MW for 451GWh/an.

The extension of Bumbuna dam is considered. Moreover, the localization of the
project along the CLSG line would make possible to share this resource in the
region. This project is very interesting economically speaking.

No feasibility study or of impact could be collected for this project.

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

Mano River

Located on the routing of the CLSG line, at the border between Sierra Leone and
Liberia, the Mano River site is a very important regional project.

If countries develop their national hydroelectric resources (Saint-Paul in Liberia, and
Bumbuna and Benkongor in Sierra Leone), this project will become interesting on a
vaster level than these two countries and it will completely justify its regional status.

Soubré

Ivory Coast has a dense hydrographic network characterized by four large rivers
which run from the North to the South. These rivers are from West to East:

• Cavally,
Sassandra,

• Sassandra,

• Bandama,
Comoé.

• Comoé.

Among these four rivers, Sassandra has the most important annual inflows and
experiences the least effect by climatic variations because of its situation in forest
zone of its basin. The former studies showed that the recognized sites of the
Sassandra basin represent a potential power of 1100 MW for an annual potential
production of 5900 GWh. Among these sites, only Buyo dam with 165 MW of
installed capacity and 850 GWh of annual production is in service since 1980. The
Sassandra River is thus equipped to 15% of its potentiality. Thus, the realization of
the hydroelectric dam of Soubré arises like a continuation of the progressive
development of the Sassandra River.

Among these four rivers, Sassandra has the most important annual inflows and
experiences the least effect by climatic variations because of its situation in forest
zone of its basin. The former studies showed that the recognized sites of the
Sassandra basin represent a potential power of 1100 MW for an annual potential
production of 5900 GWh. Among these sites, only Buyo dam with 165 MW of
installed capacity and 850 GWh of annual production is in service since 1980. The
Sassandra River is thus equipped to 15% of its potentiality. Thus, the realization of
the hydroelectric dam of Soubré arises like a continuation of the progressive

development of the Sassandra River.

| Reserve | \[m\] | RN152 | RN157.5 | RN164 |
| --- | --- | --- | --- | --- |
| Production(guaranteed energy) | \[GWh/an\] | 1116 | 1300 | 1480 |
| Installed capacity | \[MW\] | 270 | 288 | 328 |
| Firm capacity | \[MW\] | 50 | 160 | 280 |
| People to be moved |  | 2955 | 6401 | 16285 |
| Surface of reservoir | \[km2\] | 17.3 | 60 | 172 |

This project, located at the junction between the countries of zone B and the
countries of zone A could be connected to an important network node allowing its
evacuation towards the countries crossed by the CLSG line, towards the northern
areas through the axis Soubré-Man-Ferkessedougou-Sikasso/Bobo Dioulasso, or
finally towards the southern areas through the Coastal backbone.

Table 50 - Description of the Soubré project

Boutoubré

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

The site of Boutoubré located at 50 km from the town of Soubré downstream, and
80 km from the town of Sassandra could be equipped with a hydroelectric dam to
increase the capacity of the electric production park of 156 MW and 785 GWh.

Just like the Soubré project, the Boutoubré project is located on the Sassandra River
whose potential is still relatively unexploited.

Just like the Soubré project, the Boutoubré project is close to several evacuation
axes towards the West (CLSG), the north (North-South axis Ivory Coast, Ivory
Coast-Mali interconnection and Ivory Coast-Burkina Faso interconnection) and the
south-east (Coastal backbone).

Tiboto

The site of Tiboto, on Cavally River, is an excellent regional project. Located at the
border between Liberia and Ivory Coast, it is perfectly justified economically.

The feasibility studies are not yet available for this project but the points of attention
will be the topographic, geological, geotechnics and hydrological aspects.

Zungeru

The project of hydroelectric plant of Zungeru is located on the Kaduna River in the
state of Niger in Nigeria, downstream from the hydro power plant of Shiroro. With
this project, Nigeria would reduce its dependence on gas for the electrical
production. Lastly, it could be useful for the agricultural irrigation of the local
communities. The alternative selected here mentions 700MW but the installed
capacity could vary from 600MW to 950MW, with different impacts on the
environment.

Moreover, coupled with the development of the Median backbone, this installation
would also allow supplying the northern areas of the neighbouring countries (Benin,
Togo and Ghana) at lower costs.

Mambilla

In addition to the project with regional vocation of Zungeru the Mambilla project
(2600 MW) seems a very important project for the region.

Consequently only 2 projects are adopted:

2.5.4.2. REGIONAL THERMAL PROJECTS

Being given its localization in Nigeria, far from the borders with the other countries
of West Africa, it could nevertheless be directly connected to the regional network
through a 760kV transmission line.

| Site | Country | Technology | Capacity \[MW\] | Commissioning |
| --- | --- | --- | --- | --- |

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

| Salkadamna | Niger | Coal | 200 | >2020 |
| --- | --- | --- | --- | --- |
| South | Togo | Combined Cycle | 450 | 2020 |

Table 51 - Thermal projects with regional vocation

Coal project in Niger

The coal project in Niger is essential for the load supply in the north-east area of the
WAPP. Indeed, in this area, the gas and hydroelectric resources are limited, which
tends to strongly increase the marginal cost.

Let us note that on a purely economic level, this project would be justified only after
2020 but that implies that many hydroelectric projects are built in the countries of
zone B and that no technical constraint is opposed to the export of this energy
towards the northern areas of the WAPP. It is consequently probable that this project
will be essential in a shorter term.

Moreover, the North-core transmission project will allow the division of this energy
between Niger, Burkina Faso, Benin and the north of Nigeria.

Combined Cycle project in Togo

Among the countries crossed by the Coastal backbone, Togo is the only one without
any combined cycle project (WAPP or national).

In the absence of such project, the country would become strongly importer and the
gas coming from Nigeria would be unexploited.

Consequently, it is essential to consider a combined cycle project in this country in
the long term.

2.5.5. Regional transmission projects

In the long term, the hydroelectric projects should become the key of the energy
production in West Africa. Guinea having an immense tank is brought to become
strongly exporting in the next decades. The other countries with a strong
hydroelectric potential (in particular Liberia, Sierra Leone and Ivory Coast) should
also contribute in an important way to the electrical production of the area.
Consequently, the interconnection projects of these countries with their neighbors

Consequently, the interconnection projects of these countries with their neighbors
should be capital to allow the optimal exploitation of the hydroelectric potential of
the area. Let us note the interest of the already decided or planned projects: Guinea
– Mali interconnection, Mali - Ivory Coast interconnection, CLSG interconnection
and OMVG loop. Other projects could still appear to reinforce this area. These
projects are discussed hereafter.
The countries having natural gas will also have a big role to play in terms of

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

On the contrary, the countries without important hydroelectric resources and no
natural gas supply (as Burkina Faso for example) will naturally become importers of
electricity in a market based exclusively on the economic criteria and without
constraints of transit.

Consequently, the axes permitting to feed the importing areas of electricity will also
have a considerable role to play. The axis Mali - Burkina Faso - Ghana will be a
very important section for the supply of the demand for electricity of the Center-
North of the area.

2.5.5.1. PROJECTS CONSIDERED

Median backbone project

From a purely economic point of view, this interconnection is not a priority.

Indeed, with the production projects considered and suggested for Benin (combined
cycle of Maria Gleta - 450 MW) and for Togo (standard combined cycle - 450 MW),
the northern areas of these countries would be fed directly by the local production
means.

Nevertheless, if Zungeru project were considered at regional level, it would be
essential to build an axis allowing the evacuation of this energy towards the other
countries of the area. Because of the localization of this hydroelectric project, the
Median backbone would be an excellent mean to share the resources.

Lastly, let us remind that other aspects, and in particular the technical side could
amend this project.

Interconnection Liberia - Ivory Coast

A coastal interconnection between Monrovia in Liberia and San Pedro in Guinea is
evoked by the countries concerned. This project would allow in particular the
evacuation of the hydroelectric project of Tiboto (Cavally), at the border between
the two countries.

The first phase of the OMVS-OMVG interconnection relates to the Kayes-
Tambacounda section. As of the commissioning of the hydraulic site of Gouina
(decided project, commissioning estimated in 2017), it will indeed be necessary to
reinforce the 225 kV network towards Dakar so that Senegal can profit from the
shares of this project which return to him.

Since this production project belongs to the very competitive projects and that its
characteristics justify its regional character, this axis should be built at the same time
than the hydroelectric installation.

Based on purely economic consideration, the Senegalese load would be rather fed by
local coal units whereas the hydroelectric potential of Mali would allow the supply
of the northern zones of the WAPP. Therefore, the axis Kayes-Tambacounda does
appear as a priority.

Interconnections OMVS-OMVG

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

However taking the quotas of the countries into account in the OMVS projects, this
line is important for Senegal even if it does not come out of the economic study.

The second phase of the OMVS interconnection relates to the Linsan-Manantali
section to interconnect the dam projects on the Guinean territory: Boureya and
Koukoutamba.

These two production projects are among the most interesting projects on the
economic plan. Nevertheless, this layout connects two strongly producing zones of
electricity and does not really allow the evacuation of the power towards importing
zones. Moreover, the routing of this axis could be re-examined for environmental
questions. Consequently, other alternatives should be under consideration for
Boureya and Koukoutamba. Since the benefit of this routing on the economic
optimum is to interconnect the hydroelectric projects of the area, the environmental
aspects will be decisive to define the best routing for this interconnection.

2.5.5.2. OTHER INVESTMENT OPTIONS

In addition to the projects under consideration by previous studies, new projects are
proposed for optimization in Prele.

Guinea (Fomi) - Ivory Coast (Boundiali) project

This project is very important to allow the evacuation of the hydroelectric power of
Mali towards the northern areas having a very high marginal cost. In particular it
could allow the evacuation from the great hydroelectric projects under consideration
in Guinea like Amaria and Kassa and would help reducing the marginal cost in the
North of Ivory Coast, in the area of Sikasso in Mali and Burkina Faso.

Moreover, the investment cost of this project should be relatively limited since it
could join the axis Man-Laboa-Boundiali-Ferkessedougou with connection at
Boundiali from Fomi. In this case, the length of the line to be built would be limited.
The layout will have to be discussed with the environmental criteria.

The optimization tool brings this axis into service from 20180 on for an installed
capacity estimated at 2\*250MW. The economic optimum wants to strongly charge
this axis with an average flow with 327MW in 2020.

Reinforcement of the decided or planned existing axes

In the long term, the optimization tool considers the doubling of certain sections
already existing, decided or considered.

Guinea - Mali (Sikasso) project

This project should have a capital cost higher than the Guinea-Ivory Coast
(Northern) project evoked previously. Indeed, this axis Fomi-Sikasso is longer than
the Fomi- Boundiali interconnection.

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

• The feeding of the Northern region (Mali, Burkina Faso) from hydro sites of
Guinea requires the strengthening of several sections upstream and downstream
of the proposed line Fomi-Boundiali. Thus, a second line may be needed on the
axis Linsan-Fomi in order to evacuate the power produced around Linsan by the
hydro plants of Souapiti, Amaria and Grand Kinkon. This reinforcement should
be made upon arrival of the hydro or 2018.
Similarly, the sections Boundiali-Ferkessedougou-Bobo and Bobo-

• Similarly, the sections Boundiali-Ferkessedougou-Bobo and Bobo-
Ouagadougou and should be reinforces to allow the supply of Burkina Faso since
2018.
With the many hydroelectric projects under consideration in Sierra Leone and

• With the many hydroelectric projects under consideration in Sierra Leone and
Liberia (Bumbuna, Benkongor, Mano River, Mount Coffee and Saint-Paul), the
doubling of the CLSG line could become necessary after 2018. This line will be
built to allow the commissioning of a second circuit. Consequently, the cost
overrun which would be generated should be limited.
In zone A, the thermal projects under consideration in the countries, and in

• In zone A, the thermal projects under consideration in the countries, and in
particular the regional projects (combined cycle of Maria Gleta and standard
combined cycle suggested in Togo after 2020) could require a reinforcement of
the Coastal backbone in the long term. In particular the section between Togo
(Lome) and Benin (Sakété) should be reinforced with the arrival of the regional
production project (450 MW combined cycle) in Togo.
• The commissioning of Salkadamna power plant will require the construction of

• The commissioning of Salkadamna power plant will require the construction of
a 330 kV line connecting this plant to the North-core interconnection and
allowing the evacuation of the power produced towards the north of Benin and
Burkina Faso. Moreover, a 132 kV axis should be built between this power plant
and the Center-East area in Niger to allow the supply of this area at a lower
marginal cost.
Lastly, in Nigeria, the North-South reinforcements under consideration in the

• Lastly, in Nigeria, the North-South reinforcements under consideration in the
national development plans should be sufficient to feed the northern areas of the
WAPP.

2.5.5.3. SYNTHESIS OF THE REGIONAL TRANSMISSION PROJECTS

The table below shows the principal transmission developments selected by the
optimization tool based on purely economic criteria, in addition to the decided and
planned projects. Moreover, the lines justified by associated regional projects are
indicated in italic.

| Name | Associated production project | Commissioning | Capacity |
| --- | --- | --- | --- |
| Liberia(Monrovia)-Ivory Coast(San Pedro) | Tiboto | 2018 | 150MW |
| Interconnection OMVS(Linsan-Manantali) | Koukoutamba,Boureya,Balassa,Badoumbé | 2018 | 250MW |
| Guinea(Fomi)-Ivory Coast(Boundiali)(two circuits) |  | 2018 | 2x250MW |
| Linsan-Fomi second line) | Souapiti | 2018 | 250MW |
| Boundiali-Ferke-Bobo(second line) |  | 2018 | 250MW |
| Bobo-Ouaga(second line) |  | 2018 | 250MW |
| CLSG line(second circuit) |  | >2020 | 250MW |
| Coastal backbone sectionLomé-Sakété(second circuit) |  | >2020 | 312MW |

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

| Salkadamana-Niamey | Salkadamna | >2020 | 200MW |
| --- | --- | --- | --- |
| Salkadamana-CenterEast | Salkadamna | >2020 | 100MW |
| Median backbone |  | >2020 | 300MW |

Table 52 - Synthesis of the regional transmission projects (economic criteria)

2.5.5.4. AVERAGE FLOWS BY 2020

By 2020, the tendencies evoked here before, namely the exporting tendency of the
countries having a strong hydroelectric potential should already be very marked.
Thus, the axis Guinea - Mali - Burkina Faso, CLSG interconnection and OMVG
loop but also a new line proposed connecting Guinea to the North of Ivory Coast

are very strongly charged.

Moreover, the axes allowing the supply of the northern areas from the areas having
hydroelectric or gas resources also experience an increase of average flow. One
notes thus the axes Mali-Burkina Faso-Ghana and Ivory Coast-Burkina Faso.

The Coastal backbone is very charged by 2020. This tendency will be increasing
after this period, requiring inter alia the reinforcement of the section between Togo
and Benin.

Since Figure 40 represents average flows by 2020 in the reference scenario, the coal
project of Niger is not brought yet into service. This is why the country imports its
energy. After the commissioning of Salkadamna, flows will be reversed on the
North-core interconnection.

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A is forbidden without prior written approval

to third parties

ny duplication or transmission

Figure 40- Average flows on the interconnection lines in 2020 - reference scenario

This document is the property of Tractebel Engineering S.A. A

MP-WAPP/4NT/221291/002/00 October 2011 112/273

* * *

2.6. Comparison of the scenarios

The comparison between the actualized total costs of

• The scenario presenting the optimization of the national production without
increase of interconnections;
The scenario without transit limits between countries;

• The scenario without transit limits between countries;
The reference scenario.

• The reference scenario.

Gives the profit the area can hope for in terms of optimization of the production.

The actualized profit takes into account the reduction of unserved energy, but also
the possibility of supplying the load with more competitive energy sources.

In this context, the maximum profit hoped for the area of West Africa was estimated
at nearly 6 billion dollars, i.e. more than 10% of the discounted cost of the reference
scenario. Let us remind however that this profit is hypothetical since it supposes that
the lines are available as of today and with an infinite capacity. It corresponds to the
difference between the costs of scenarios 1 and 2.

The reference scenario presents the optimal regional development of the electric
system of production and transport by holding account limits of transit on the
interconnections. In this case, the profit hoped compared to the situation without
new interconnections was estimated at 3 billion dollars.

| Summary of the costs(kUSD) | Scenario 1 | Scenario 2 | Scenario 3 |
| --- | --- | --- | --- |
|  | Without new interconnection | Without transit limits | Reference scenario |
| Investments costs |  |  |  |
| Generation units | 6316.334 | 6868.480 | 7010.508 |
| Transmission lines |  |  | 103.061 |
| Fixed costs of the generation units | 1012.092 | 836.852 | 953.520 |
| Variable costs of electricity(except natural gas) | 11517.466 | 4125.571 | 8360.262 |
| Cost of natural gas | 39373.910 | 40352.594 | 38701.317 |
| Total | 58219.802 | 52183.497 | 55128.668 |

Table 53 - costs of scenarios 1, 2 and 3

to third parties is forbidden without prior written approval
ny duplication or transmission
Engineering S.A. A
This document is the property of Tractebel

* * *

2.7. Studies of sensitivity

The objective of this chapter is to analyze various alternatives and compare them to
the reference scenario, to emphasize the influence of certain key parameters on the
optimization results.

These alternatives will analyze successively the impact:

• Of a delay of 2 years in the commissioning of the planned transmission projects;
Of a lower demand growth in the various countries;

• Of a lower demand growth in the various countries;
Of a renewable constraint of 10% of production capacity (without hydro) from

• Of a renewable constraint of 10% of production capacity (without hydro) from
2020 on;
Of a low fuel cost (based on 75$/bbl instead of 100$/bbl);

• Of a low fuel cost (based on 75$/bbl instead of 100$/bbl);
Of a high fuel cost (based on 125$/bbl instead of 100$/bbl);

• Of a high fuel cost (based on 125$/bbl instead of 100$/bbl);
Of a low actualization rate (of 8% instead of 10%);

• Of a low actualization rate (of 8% instead of 10%);
Of a high actualization rate (of 12% instead of 10%);

• Of a high actualization rate (of 12% instead of 10%);
Of a reduction of the possible investments in the hydroelectric candidate projects

• Of a reduction of the possible investments in the hydroelectric candidate projects
in Guinea in order to take into account the technical constraints and especially
the constraints of financing related to the mobilization of an enormous capital.
In order to analyze the impact of these alternatives, the discounted costs calculated

In order to analyze the impact of these alternatives, the discounted costs calculated
will be compared with those calculated for the reference scenario (presented in the
table below). Let us note that these costs do not include the capital costs of the
imposed projects not impacting optimization, i.e. the decided and planned
transmission projects as well as the decided production projects.

2.7.2. Alternative with delay of the transmission projects

| Summary of the costs(kUSD) | Scenario3 |
| --- | --- |
|  | Reference scenario |
| Investments costs |  |
| Generation units | 7010508 |
| Transmission lines | 103061 |
| Fixed costs of the Generation units | 953520 |
| Variable cost of electricity(except natural gas) | 8360262 |
| Cost of natural gas | 38701317 |
| Total | 55128668 |

This alternative consists in regarding a delay of two years for the commissioning of
the planned transmission projects and for the OMVG project.

Table 54 - costs of the reference scenario

to third parties is forbidden without prior written approval
ny duplication or transmission
Engineering S.A. A
This document is the property of Tractebel

* * *

| Summary of the costs(kUSD) | Scenario3 | Scenario4 |
| --- | --- | --- |
|  | Reference scenario | Delay of the transmission projects |
| Total | 55128668 | 55374609 |

Table 55 - Costs of the scenario with delay of the transmission projects

The principal change of this alternative compared to the reference scenario is the
more important use in the short term of liquid fuels in local units for the electric
production.

The important modifications concerning the investment decisions in production in
this alternative are mentioned below:

• The delay of the OMVG loop makes the investments in candidate thermal units
essential in The Gambia (combined cycle of 60 MW) like in Guinea Bissau
(HFO plant of 55 MW). It also extends the use of HFO units in the isolated
centers of Ziguinchor and Tambacounda in Senegal and new investments in heat
capacities to feed these centers (approximately 28 MW and 30 MW additional
capacities invested respectively in each one of them from 2017 on to compensate
the deficit) become necessary. Let us note that before 2019, the marginal prices
of electricity are naturally higher in this alternative than in the reference case for
the above mentioned nodes.
The connection delay between the nodes of Linsan and Fomi in Guinea (Guinea-

• The connection delay between the nodes of Linsan and Fomi in Guinea (Guinea-
Mali project delayed from 2016 to 2018) provokes a necessary investment of 10
MW in thermal capacities in to Fomi in the short-term before the appearance of
the local hydroelectric projects.
Let us note that there is no major difference between this alternative and the

Let us note that there is no major difference between this alternative and the
reference scenario concerning the investments choices neither in considered lines
nor in reinforcements and new lines proposed.

This alternative confirms the interest to develop the planned transmission projects as
well as the OMVG project with the commissioning dates envisaged. If these projects
were both delayed of two years, an additional discounted cost of approximately
246M$ should be supported by the countries of the area.

2.7.3. Alternative with a lower load growth

| Summary of the costs(kUSD) | Scenario3 | Scenario5 |
| --- | --- | --- |
|  | Reference scenario | Low demand growth |
| Total | 55128668 | 49337339 |

This alternative considers a scenario with a low growth of the electric demand,
compared with the reference scenario. The electric demand taken into account
(annual point and energy) corresponds to the low scenarios of section 2.2.3. Load
forecast

£Table 56 - Costs of the scenario with low demand growth

to third parties is forbidden without prior written approval
ny duplication or transmission
Engineering S.A. A
This document is the property of Tractebel

* * *

Adopting the approach of a low demand growth allows reducing all costs at the
horizon of the study. The discounted costs are reduced by 10.5% compared to the
reference scenario.

The important modifications implied by this alternative as for the investment
decisions in candidate production units are mentioned below:

• The commissioning of a certain number of hydraulic projects is delayed of
approximately a year because of the lower demand. They are the projects of,
Mano River between Sierra Leone and Liberia, and Gribo Popoli in Ivory Coast.
In Liberia, only the site of St Paul 1B (78 MW) is justified at the horizon of the
study and the site of St Paul 2 (120 MW) is not justified anymore.
The commissioning steps for the Coal plant of Salkadamna in Niger are also

• The commissioning steps for the Coal plant of Salkadamna in Niger are also
shifted so that the whole 200 MW are only necessary two years later, compared
to the reference scenario.
Concerning the other thermal candidate units, it should be noted that there is, in

• Concerning the other thermal candidate units, it should be noted that there is, in
this alternative, no more need for building combined cycles in The Gambia or
Togo. In the same way, only the candidate project of a second combined cycle T3
(120 MW) is necessary in Ghana, with a deferred commissioning of 6 years
compared to the reference scenario.
The principal changes concerning the investment decisions in the transmission lines

The principal changes concerning the investment decisions in the transmission lines
(projects considered, reinforcements, and new lines suggested) are mentioned below:

• In this alternative, the Linsan-Manantali interconnection is also justified for the
exchanges of power between Guinea and Mali
Installation of a 2nd circuit on the CLSG interconnection for the section

• Installation of a 2nd circuit on the CLSG interconnection for the section
Monrovia (Liberia) - Man (Ivory Coast) is not justified economically any more
because less hydroelectric projects are invested in these countries.
• The reinforcement of the Coastal backbone between Togo and Benin is not

• The reinforcement of the Coastal backbone between Togo and Benin is not
justified any more since the combined cycle of Togo is not selected any more
among the investment options.
Let us note that the interconnection suggested between the substations of Fomi in

Let us note that the interconnection suggested between the substations of Fomi in
Guinea and Boundiali in Ivory Coast remains interesting from 2020 on, even in this
alternative with low demand growth.

This alternative consists in adopting a voluntary approach of investment in
renewable electric production capacities (except hydroelectricity) so that the quota
of these capacities in the total power installed of the area reaches 10% as from 2020.

2.7.4. Renewable alternative

This alternative tends to show that, even in the event of a lower load growth, the
regional transmission projects to evacuate the power from Guinea remain of utmost
importance for the area. On the other hand, the combined cycle project in Togo who
has a regional vocation will be justified at the horizon of the study only if the load
growth is considerable.

to third parties is forbidden without prior written approval
ny duplication or transmission
Engineering S.A. A
This document is the property of Tractebel

* * *

Lastly, the quota of 10% of the yearly peak load was maintained until the end of the
study period. Thus, renewable capacity imposed in 2025 reached more than 3500
MW.

The table below summarizes the minimum capacities constraints on renewable
production imposed to the optimization for each year as previously explained.

| Year | Imposed capacity of renewable generation (out hydro)\[MW\] |
| --- | --- |
| 2016 | 500 |
| 2017 | 1000 |
| 2018 | 1500 |
| 2019 | 2000 |
| 2020 | 2500 |
| 2021 | 2700 |
| 2022 | 2900 |
| 2023 | 3150 |
| 2024 | 3400 |
| 2025 | 3650 |

Table 57 - Renewable capacity (without hydro) imposed per year for the scenario of voluntary investment into
renewables

In order to achieve these goals, the renewable candidate projects already known in
the countries of the area (presented in the section 2.2.4.2 “Development plans of the
park of production”) were forced in the optimization.

In addition to these already known candidate projects and to the decided renewable
projects, it was necessary to add additional investment options in the countries of the
area, as presented in the table below.

to third parties is forbidden without prior written approval
ny duplication or transmission
Engineering S.A. A
This document is the property of Tractebel

* * *

| Country | Technologies and renewable capacities envisaged for the decided and known candidates projects | Technologies and renewable capacities suggested for additional investments (as from 2016,2021) |
| --- | --- | --- |
| Senegal | biomass(30MW) | wind(100MW,100MW) |
| wind(125MW) | solar photovoltaic(100MW,100MW) |  |
| solar photovoltaic(7.5MW) |  |  |
| The Gambia | wind(11MW) | wind(40MW,40MW) |
| solar photovoltaic(10MW) | solar photovoltaic(20MW,20MW) |  |
| Guinea Bissau | no renewable candidate projects known | solar photovoltaic(20MW,20MW) |
| Guinea | no renewable candidate projects known | no renewable technologies suggested because massive hydroelectric investments |
| Sierra Leone | biomass(115MW) |  |
| solar photovoltaic(5MW) | biomass(125MW,125MW) |  |
| Liberia | biomass(35MW) | biomass(35MW,35MW) |
| solar photovoltaic(20MW,20MW) |  |  |
| Mali | biomass(18MW) |  |
| solar photovoltaic(80MW) | solar photovoltaic(150MW,150MW) |  |
| solar thermal(50MW,50MW) |  |  |
| biomass(20MW,20MW) |  |  |
| no renewable candidate projects known | no renewable technologies suggested because massive thermal investments with local gas and little wind and solar resources |  |
| wind(150MW) |  |  |
| solar photovoltaic(10MW) | wind(100MW,100MW) |  |
| solar photovoltaic(100MW,100MW) |  |  |
| Togo | wind(20MW) |  |
| solar photovoltaic(5MW) | wind(50MW,50MW) |  |
| solar photovoltaic(25MW,25MW) |  |  |
| solar photovoltaic(30MW) | solar photovoltaic(70MW,70MW) |  |
| Burkina Faso | solar photovoltaic(43MW) |  |
| solar thermal(4MW) | solar photovoltaic(150MW,150MW) |  |
| solar thermal(50MW,50MW) |  |  |
| wind(30MW) |  |  |
| solar thermal(50MW) | wind(30MW,30MW) |  |
| solar photovoltaic(20MW,20MW) |  |  |
| Niger | wind(30MW) |  |
| solar thermal(50MW) | wind(30MW,30MW) |  |
| solar photovoltaic(250MW,250MW) |  |  |
| biomass(200MW,200MW) |  |  |
| Nigeria | no renewable candidate projects known | wind(300MW,300MW) |
| solar photovoltaic(250MW,250MW) |  |  |
| biomass(200MW,200MW) |  |  |

The capacities and technologies suggested were selected to avoid a too significant
part of intermittent production in the energy mix of each country and to try
developing the technologies already existing or with high potentials within each
country (based on the information of section 2.2.2.2 and on the document
« Renewable Energies in West Africa, Regional Report on Potentials and Markets –
17 Country Analyses » published by the German Federal Ministry for Economic
Cooperation and Development).

Table 58- Renewable capacity and technologies (without hydro) of the decided projects, known candidates and additional
investment options suggested

to third parties is forbidden without prior written approval
ny duplication or transmission
Engineering S.A. A
This document is the property of Tractebel

* * *

The distribution of the capacities suggested in the countries was selected in order to
match the localization of the local renewable resources and to take into account the
importance of the load. The data used about costs and availabilities of the renewable
resources were presented in sections 2.2.2.2 and 2.2.4.1.

| Summary of the costs(kUSD) | Scenario3 | Scenario6 |
| --- | --- | --- |
|  | Reference scenario | Voluntary renewable investment |
| Total | 55128668 | 56251999 |

Table 59 - Costs of the scenario with voluntary renewable investments

Logically, the cost difference with the reference scenario appears mainly in higher
capital costs (and fixed cost) for the generation units in the renewable alternative.
This cost overrun is partly compensated by the reduction in the natural gas and
liquid fuel consumption, so that the total discounted costs increase compared with
the reference scenario globally reaches 1 123 M$, which corresponds, relatively, to
an increase of 2%.

The results of the economic optimization for this alternative are presented in the
graphs below. They show for 2020 and 2025 the total renewable capacities which
will have to be installed by country and by technology to respect the renewable
constraint of 10% of installed capacity in the area.

Installed capacity of renewables in 2020 (without
hydro)

Figure 41 - Renewable installed capacity by country in 2020 (except hydro) for the voluntary scenario of renewable
investment

to third parties is forbidden without prior written approval
ny duplication or transmission
Engineering S.A. A
This document is the property of Tractebel

* * *

Figure 42 - Renewable installed capacity by country in 2025 (except hydro) for the voluntary scenario of renewable
investment

Various comments can be done about these results:

• The biomass is the second least expensive renewable technology. Nevertheless
the additional investments suggested in this technology (compared to the known
projects) are retained only in Nigeria. One of the reasons is for example the fact
that Sierra Leone, albeit its high biomass potential, can develop less expensive
hydroelectric resources for an exportation purpose.
The additional investments suggested in photovoltaic technology are retained to

• The additional investments suggested in photovoltaic technology are retained to
complete the two previous technologies to satisfy the imposed constraint.
• Except the thermal solar projects (CSP) already known (and thus imposed in this

• Except the thermal solar projects (CSP) already known (and thus imposed in this
alternative) in Mali and Niger, no new project arises from optimization, because
of the high cost per kWh of this technology (primarily because of the capital
costs and the fixed costs), much higher than for solar photovoltaic and other
renewable technologies.
The important modifications concerning the investment decisions in thermal and

• In Liberia, the St Paul projects (1B and 2) are not justified anymore at the
horizon of the study. The commissioning of several hydroelectric projects is
delayed: Digan (2 years), Boureya (1 year), Kouravel (1 year), Manor River (1
year) and Gribo Popoli (1 year).
• The complete commissioning of the 200 MW coal project in Salkadamna in

The important modifications concerning the investment decisions in thermal and
hydroelectric production in this alternative are mentioned below:

• The complete commissioning of the 200 MW coal project in Salkadamna in
Niger is delayed of one year.

to third parties is forbidden without prior written approval
ny duplication or transmission
Engineering S.A. A
This document is the property of Tractebel

* * *

• There is, in this alternative, no more need for building a combined cycle in The
Gambia. The commissioning steps for the candidate combined cycles in Ghana
are shifted in the future and approximately 200 MW less are invested in this type
of units in Ghana by 2025 compared with the reference scenario. The combined
cycle suggested in Togo remains interesting, but only in the long term, after
2022\. 6000 MW of cycles combined with Nigeria remain also interesting and this
in the short term.
The principal changes concerning the investment decisions in transmission lines

The principal changes concerning the investment decisions in transmission lines
(projects considered, reinforcements, and new lines suggested) are mentioned below:

• The Linsan-Manantali interconnection is not really justified any more.
In Nigeria, a reduction of approximately 400 MW in transport capacity will be

• In Nigeria, a reduction of approximately 400 MW in transport capacity will be
necessary between the south and the center of the country in 2025, compared
with the reference scenario. This is due to the fact that wind and solar
photovoltaic projects appear in the northern and center areas for this alternative.

The interconnection suggested between the substations of Fomi in Guinea and

• The interconnection suggested between the substations of Fomi in Guinea and
Boundiali in Ivory Coast remains very important in this alternative.
In conclusion, it appears that the overall investment and operation costs of the

In conclusion, it appears that the overall investment and operation costs of the
production park and the grid do not increase in a considerable way with the
implementation of a renewable policy. Moreover, such policy would make it
possible to decrease the energy dependence of certain countries (Burkina Faso and
The Gambia in particular) and to reduce the dependence on fossil fuels of countries
very dependant on gas (Nigeria in particular).

Thus, it would be possible to support at regional level:

• A project of one or more wind farms for an installed capacity of 200MW to
distribute between Senegal and The Gambia. These countries indeed have an
interesting potential along the Atlantic coast. Moreover, Senegal and The Gambia
already have projects at national level, showing the willingness of these countries
to develop these resources.
The construction of wind farms for a total of 300 MW in Nigeria to decrease

• The construction of wind farms for a total of 300 MW in Nigeria to decrease
the energy dependence of the north of Nigeria and to reduce the fossil fuel
consumption in this country.
The development of solar photovoltaic projects for a total of 150 MW in

• The development of solar photovoltaic projects for a total of 150 MW in
Burkina Faso (in addition to the projects already under consideration by the
country and the local industries) in order to reduce the marginal cost of the
country. The country has an interesting photovoltaic potential and shows its
willingness to develop renewable energies on its territory.
• The development of solar photovoltaic projects for a total of 150 MW in Mali
(in addition to the projects already under consideration by the country and the

• The development of solar photovoltaic projects for a total of 150 MW in Mali
(in addition to the projects already under consideration by the country and the
local industries) in order to reduce energy imports in this country and to foster
the interesting PV potential on its territory.

to third parties is forbidden without prior written approval
ny duplication or transmission
Engineering S.A. A
This document is the property of Tractebel

* * *

2.7.5. Alternative low fuels cost

The purpose of this alternative is to analyze the effect of a decreased fuel cost
compared to the reference scenario. With this intention, the fuel prices considered
were aligned on a crude oil price of 75$/bbl instead of 100$/bbl in the reference
scenario. The values of these lowered prices are included in section 2.2.2.1 “Price of
fuels”. Let us note that the prices considered for biomass fuels were not adapted
because of their low sensitivity compared to the crude oil price.

| Summary of the costs(kUSD) | Scenario3 | Scenario7 |
| --- | --- | --- |
|  | Reference scenario | Low fuels cost |
| Total | 55128668 | 44647252 |

Table 60 - Costs of the scenario with low fuels cost

A considerable reduction of 19% of the actualized total costs is observable in this
alternative compared with the reference scenario. This reduction is primarily due to
the reduction of the natural gas cost which provokes a global reduction of about 15%
in the total discounted costs.

The important modifications concerning the investment decisions in production for
this alternative are mentioned below:

• The commissioning of a certain number of hydroelectric projects is delayed by
the optimization because of the possibility of supplying the load with thermal
units at low costs. The commissioning of Kétou in Benin is thus delayed of 5
years compared to the reference scenario; the sites of Mano River between Sierra
Leone and Liberia and Gribo Popoli in Ivory Coast are delayed of 3 years;
finally, the site of Aboisso Comoé in Ivory Coast is delayed of 2 years. In
Liberia, the projects St Paul (1B and 2) are not justified any more at the horizon
of the study.
• Concerning the coal candidate production units, it should be noted that the 200

• Concerning the coal candidate production units, it should be noted that the 200
MW project of Salkadamna in Niger is not justified any more here by economic
optimization.
In Ghana, the investment in combined cycles with gas is reinforced: 200 MW

optimization.
• In Ghana, the investment in combined cycles with gas is reinforced: 200 MW

Let us note that the 6000 MW investment in combined cycles in Nigeria which arose
from the reference scenario is still justified in this alternative and this in spite of a
lower gas cost which is consequently not low enough to justify the operation of open
cycle gas turbines as base units.

• In this alternative, the Linsan-Manantali interconnection is also justified for the
power exchanges between Guinea and Mali.

to third parties is forbidden without prior written approval
ny duplication or transmission
Engineering S.A. A
This document is the property of Tractebel

* * *

• Installation of a 2nd circuit on the section Monrovia (Liberia) - Man (Ivory
Coast) of the CLSG project is not justified economically any more.
The interconnection suggested between the substations of Fomi in Guinea and

• The interconnection suggested between the substations of Fomi in Guinea and
Boundiali in Ivory Coast is slightly less charged in this alternative since less
hydroelectric projects are selected by the economic optimum but it remains
nevertheless competitive.

2.7.6. Alternative high fuels cost

The purpose of this alternative is to analyze the effect of an increased fuel cost
compared to the reference scenario. With this intention, the fuel prices considered
were aligned on a crude oil price of 125$/bbl instead of 100$/bbl in the reference
scenario. The values of these increased prices are included in section 2.2.2.1 “Price
of fuels”. Let us note that the prices considered for biomass fuels were not adapted
because of their low sensitivity compared to the crude oil price.

| Summary of the costs(kUSD) | Scenario3 | Scenario8 |
| --- | --- | --- |
|  | Reference scenario | High fuels costs |
| Total | 55128668 | 65374071 |

Table 61 - Costs of the scenario with high fuels costs

A significant growth of 18.5% of the actualized total costs is observable in this
alternative compared with the reference scenario. This growth is primarily due to the
cost of the natural gas which alone increases the total discounted costs of about 15%.

• The important modifications concerning the investment decisions in production
in this alternative are mentioned below:
Certain hydroelectric projects which did not come out of the optimization in the

• Certain hydroelectric projects which did not come out of the optimization in the
reference scenario are now economically justified in this alternative for a
commissioning between 2020 and 2025. They are the projects of Fello Sounga
(OMVG) in Guinea, Tiassalé in Ivory Coast and Gambou in Niger.
The commissioning of certain projects is also advanced compared to the

• Two renewable projects (except hydro) which did not arise from the optimization
in the reference scenario are justified economically in this alternative. They are
the biomass project (bagasse) of Sosumar in Mali and the wind project of 20MW
in Togo, which becomes interesting from 2013-2014 on.
Also, this alternative also confirms the interest of a combined cycle in south Togo

• Concerning the coal projects, Salkadamna in Niger is, in this alternative, justified
from 2015 on, i.e. 7 years in advance compared with the reference scenario.
• Two renewable projects (except hydro) which did not arise from the optimization

Also, this alternative also confirms the interest of a combined cycle in south Togo
which arose from the reference scenario.

to third parties is forbidden without prior written approval
ny duplication or transmission
Engineering S.A. A
This document is the property of Tractebel

* * *

In a general way, logically, the proportion of generated electricity in this alternative
at the horizon of the study by the thermal units running with gas and liquid fuels (at
high costs) decreases with the profit of the hydroelectric and coal units (whose cost
increase does not appear penalizing).

The principal changes concerning the investment decisions in transmission lines
(projects considered, reinforcements, and new lines suggested) for this alternative
are mentioned below:

• The Linsan-Manantali interconnection is not justified any more except for
connecting and sharing the hydroelectric resource of Boureya and Koukoutamba.
nd
The installation of a 2 circuit on the section Monrovia (Liberia) - Man (Ivory

nd
• The installation of a 2 circuit on the section Monrovia (Liberia) - Man (Ivory
Coast) of the CLSG project is economically justified in the shorter term that in
the reference scenario.

2.7.7. Alternative with low actualization rate

The purpose of this alternative is to analyze the impact of a low actualization rate
fixed at 8% instead of 10% in the reference scenario, to reflect a lower capital cost.

The important modifications concerning the investment decisions in production in
this alternative are mentioned below:

• Certain hydroelectric projects which did not arise from the optimization in the
reference scenario are now economically justified in this alternative for a
commissioning between 2020 and 2025. They are the projects of Fello Sounga
(OMVG) in Guinea, Tiassalé in Ivory Coast, Tététou in Togo, and Gambou in
Niger.
The commissioning of certain projects is also advanced compared to the

• The commissioning of certain projects is also advanced compared to the
reference scenario. It is e.g. the case of the Gribo Popoli project in Ivory Coast (4
years). In Liberia, the sites of St Paul 1B and St Paul 2 (120 MW) are justified
both in 2018 compared with 2023 and 2024 respectively in the reference
scenario.
Concerning the coal projects, Salkadamna in Niger is, in this alternative, justified

• Concerning the coal projects, Salkadamna in Niger is, in this alternative, justified
from 2015-2016 on, i.e. 7 years in advance compared with the reference scenario.
The commissioning steps of the Ghanaian projects of combined cycles are

• The installation of a 2nd circuit on the section Monrovia (Liberia) - Man (Ivory
Coast) of the CLSG project is economically justified in a shorter term that in the
reference scenario.
• An additional reinforcement of the axis between Abidjan and Soubré in Ivory

• The commissioning steps of the Ghanaian projects of combined cycles are
slightly shifted in the future.

The principal changes concerning the investment decisions in transmission lines
(projects considered, reinforcements, and new lines suggested) for this alternative
are mentioned below:

• The interconnection suggested between the sub stations of Fomi in Guinea and
Boundiali is still very interesting in this scenario.

• The Linsan-Manantali interconnection is not justified any more except for
connecting and sharing the hydroelectric resource of Boureya and Koukoutamba.
The installation of a 2nd circuit on the section Monrovia (Liberia) - Man (Ivory

to third parties is forbidden without prior written approval
ny duplication or transmission
Engineering S.A. A
This document is the property of Tractebel

* * *

Let us note that these conclusions are very close to those which emanated from the
alternative considering a high price of fuels. This is logical since a low actualization
rate supports the investments (for example in hydroelectric production units or coal
as in transmission lines) avoiding operation costs in the future (which, once
actualized, are more expensive with a low actualization rate).

2.7.8. Alternative with high actualization rate

The purpose of this alternative is to analyze the impact of a high actualization rate
fixed at 12% instead of 10% in the reference scenario, to reflect a higher capital cost.

The important modifications concerning the investment decisions in production in
this alternative are mentioned below:

• The investment in a certain number of hydroelectric projects is delayed by the
optimization in this alternative. They are the sites of Mano River between Sierra
Leone and Liberia (4 years), Gribo Popoli (3ans) and Aboisso Comoé in Ivory
Coast (3 years). In Liberia, the St Paul projects (1B and 2) are not economically
justified any more at the horizon of the study.
Concerning the candidate coal production units, it should be noted that the

• Concerning the candidate coal production units, it should be noted that the
Salkadamna project in Niger is still justified but only for 100 MW in 2024-2025
(instead of 200 MW possible and invested in the reference scenario).

In Ghana, the investment in combined cycles with gas is reinforced: 163 MW

• In Ghana, the investment in combined cycles with gas is reinforced: 163 MW
more are invested in these units by 2025 compared to the reference scenario.
Let us note that the investment in 6000 MW of combined cycles in Nigeria which

Let us note that the investment in 6000 MW of combined cycles in Nigeria which
arose from the reference scenario is still justified in this alternative, just as the
investment in a combined cycle of 450 MW in Togo.

The principal changes concerning the investment decisions in transmission lines
(projects considered, reinforcements, and new lines suggested) for this alternative
are mentioned below:

• The installation of a 2nd circuit on the section Monrovia (Liberia) - Man (Ivory
Coast) of the CLSG project is not economically justified any more.
The interconnection suggested between the substations of Fomi in Guinea and

• The interconnection suggested between the substations of Fomi in Guinea and
Boundiali in Ivory Coast is in this alternative slightly less justified.
Just like the scenario with low actualization rate was very close to the scenario with

Just like the scenario with low actualization rate was very close to the scenario with
high fuel prices, this alternative with a high actualization rate is relatively similar to
the one with low fuel prices.

to third parties is forbidden without prior written approval
ny duplication or transmission
Engineering S.A. A
This document is the property of Tractebel

* * *

2.7.9. Alternative with reduction of the candidate hydroelectric
projects in Guinea

The purpose of this alternative is to consider limited investment capacities in the
hydroelectric projects that are candidates and located in Guinea compared with the
reference scenario.

To this purpose, the less advanced projects on the plan of the studies or those located
far from the 225 kV decided and planned network for Guinea were not considered.

| Summary of the costs(kUSD) | Scenario3 | Scenario11 |
| --- | --- | --- |
| Total | Reference scenario | Reduction of the candidate hydroelectric projects in Guinea |
| 55 128 668 | 55 303 181 |  |

Table 62 - Costs of the scenario with reduction of the candidate hydroelectric projects in Guinea

In terms of actualized total costs, this alternative corresponds to a moderate cost
overrun of 175 M$ over the study period compared with the reference scenario, that
is to say an increase 0.3%. The capital costs are lowered overall because there are
fewer hydroelectric projects (expensive investment compared with the thermal
solutions) as well as the reduced transmission capacity that is necessary to export the
production of these hydro projects. The operation costs, and in particular the costs
associated with the natural gas consumption, are increased, leading to the cost
overrun mentioned.

• The commissioning of certain hydroelectric projects is advanced compared to the
reference scenario, to compensate the energy deficit provoked by putting aside
some projects in Guinea: Gribo-Popoli in Ivory Coast (advanced 3 years), Saint
Paul 1B and Saint Paul 2 in Liberia (advanced 2 years)
180 MW of additional combined cycle are justified in Ghana at the horizon of the

• The installation of a second circuit on the CLSG interconnection between
Monrovia (Liberia) and Man (Ivory Coast) is justified sooner than in the
reference scenario to export more energy from the hydroelectric sites of Liberia
and Sierra Leone.
The Interconnection suggested between the substations of Fomi in Guinea and

• 180 MW of additional combined cycle are justified in Ghana at the horizon of the
study in this alternative, to compensate the lack in hydroelectric energy
importation.
The principal changes concerning the investment decisions in transmission lines

The Interconnection suggested between the substations of Fomi in Guinea and
Boundiali in Ivory Coast is less justified in this alternative since fewer hydroelectric
projects are considered in Guinea.

• The Linsan-Manantali interconnection is not justified anymore except for
connecting and sharing the hydroelectric resource of Boureya and Koukoutamba.
The installation of a second circuit on the CLSG interconnection between

to third parties is forbidden without prior written approval
ny duplication or transmission
Engineering S.A. A
This document is the property of Tractebel

* * *

2.7.10. Synthesis of the alternatives

The alternatives show that according to the evolution of the great macro-economic
parameters that are the load growth, the actualization rate and the trend of the fuels
prices, two completely different behaviors could occur.

On the one hand, if the actualization rate suddenly decreased or if the prices of fossil
fuels increased, the hydroelectric projects would be largely favoured with the
detriment of the thermal projects (natural gas and coal).

Oppositely, if the actualization rate had suddenly increased or if the prices of fossil
fuels decreased, the hydroelectric projects would be largely underprivileged with the
profit of the thermal projects.

Consequently, it is important to maintain a balanced energy mix between the various
resources in order to ensure a reasonable discounted cost in all circumstances.

Lastly, if an energy policy based on renewable energies were implemented on the
scale of West Africa, the discounted cost would only be fairly impacted (2%) and
would allow to reduce the energy dependence of certain areas having only few
hydroelectric or gas resources.

2.8. Conclusion: Provisional list of priority projects
based on the economic criteria

The provisional list of priority projects presented hereafter and based on the
economic study relates to transmission and production projects which are added to
the transmission projects already decided and planned and to the decided production
projects which cannot be questioned any more and are described in the data in
sections 2.2.4 and 2.2.5.

2.8.1. Priority production projects

The optimal development plan of the West African area resulting of this study and
based on an exclusively economic optimization model tends to show that it is
essential to develop the hydroelectric resources in the countries of zone B, in Ivory
Coast and in Nigeria.

The mountainous regions of Forest Guinea and Fouta Djalon are the source of
many rivers which feed Guinea itself but also Liberia and Sierra Leone.

This is why regional entities (OMVS and OMVG) consider the development of the
potential of Guinea, in particular through the projects Grand Kinkon (OMVG),
Boureya, Koukoutamba and Balassa (OMVS). These projects deserve to be
supported in priority at regional level.

to third parties is forbidden without prior written approval
ny duplication or transmission
Engineering S.A. A
This document is the property of Tractebel

* * *

In addition to these projects, many other installations are considered for Guinea.
Nevertheless, for technical, environmental and financial reasons but also in order to
ensure a reasonable development cost in all circumstances (and in particular if the
cost of fuels dropped suddenly or if the actualization rate increased), it is not
reasonable to consider the commissioning of as many hydroelectric plants. Among
the great projects under consideration in the country, the project of Kassa B is
certainly one of the projects to be supported at the regional level, first of all because
its cost by GWh is one of the lowest and secondly because it has a true regional
vocation from its location at a few kilometers of the border between Guinea and
Sierra Leone. Projects of Grand Kinkon, Amaria and Souapiti have also a high
regional interest due to their economic competitiveness and their size. Particular
attention should nevertheless be made to these projects on the environmental point
of view.

In Sierra Leone, the Bumbuna project is totally justified economically and is ideally
located along the CLSG line.

Moreover, the project of Tiboto located at the border between Liberia and Ivory
Coast has a relatively competitive cost of GWh. Consequently, it could be retained
as a priority project for the countries. Let us note however that this project can be
evacuated only through one 225 kV line to build between Monrovia and San Pedro

Among the internal projects in Ivory Coast, the project of Soubré has a cost of GWh
slightly more important than Boutoubré but the size of this project (270 MW) and
the status of the preliminary studies are such that this project should be under
consideration in priority.

Finally, the project Zungeru (in the western part of Nigeria) and the project
Mambilla (on the 760kV line that will cross Nigeria) could be under consideration
at the regional level.

Within a regional framework where the macro-economic parameters could strongly
influence the discounted cost, it is important to maintain a balanced energy mix
between the various resources in order to ensure a reasonable development cost in
all circumstances. This is why thermal projects must be regarded as priority projects.

Today two priority projects were already highlighted by the WAPP. They are the
combined cycles of Aboadze in Ghana and Maria-Gleta in Benin.

The coal project in Niger is essential for the load supply in the North-east area of
the WAPP. Indeed, in this area, the gas and hydroelectric resources are limited,
which tends to strongly increase the marginal cost. In the reference scenario, this
project was considered only in the long term (after 2020) but the alternatives
showed that this project could become crucial in a shorter term. The North-core
transmission project will allow sharing this energy between Niger, Burkina Faso,
Benin and the north of Nigeria.

In addition to these projects and to projects decided by the countries, two projects
appear crucial at regional level.

to third parties is forbidden without prior written approval
ny duplication or transmission
Engineering S.A. A
This document is the property of Tractebel

* * *

Lastly, the alternatives showed that if a voluntary development scenario of
renewable energy were set up, on the scale of West Africa, the discounted cost
would be only fairly impacted (1%) and would allow reducing the energy
dependence of certain areas having only few hydroelectric or gas resources.

Thus, it would be important to support the following renewable projects first:

• A construction project of one or more wind farms for an installed capacity of
200MW (in addition to the projects already under consideration by the
countries) to distribute between Senegal and The Gambia. These countries
indeed have an interesting potential along the Atlantic coast. Moreover,
Senegal and The Gambia have already projects at national level, which shows
the willingness of these countries to develop these resources.
The construction of wind farms for a total of 300 MW in Nigeria to decrease

• The construction of wind farms for a total of 300 MW in Nigeria to decrease
the energy dependence of the north of Nigeria and to reduce the fossil fuel
consumption in this country.
The development of solar photovoltaic projects for a total of 150 MW in

• The development of solar photovoltaic projects for a total of 150 MW in
Burkina Faso (in addition to the projects already under consideration by the
country and the local industries) in order to reduce the marginal cost of the
country. The country has an interesting photovoltaic potential and shows its
willingness to develop renewable energies on its territory.
The development of solar photovoltaic projects for a total of 150 MW in Mali

• The development of solar photovoltaic projects for a total of 150 MW in Mali
(in addition to the projects already under consideration by the country and the
local industries) in order to reduce energy imports in this country and to foster
the interesting PV potential on its territory.
In conclusion the production projects considered to be priority based on economic

In conclusion the production projects considered to be priority based on economic
criterion are the followings:

| Name of the project | Country | Technology | Commissioning |
| --- | --- | --- | --- |
| Balassa, Boureya, Koukoutamba(OMVS) | Guinea | Hydro | 2020 |
| Grand Kinkon | Guinea | Hydro | 2018 |
| Kassa B | Guinea/Sierra Leone | Hydro | 2018 |
| Souapiti | Guinea | Hydro | 2018 |
| Amaria | Guinea | Hydro | 2018 |
| Bumbuna | Sierra Leone | Hydro | 2018 |
| Tiboto | Liberia/Ivory Coast | Hydro | 2018 |
| Soubré | Ivory Coast | Hydro | 2018 |
| Zungeru | Nigeria | Hydro | 2018 |
| Mambilla | Nigeria | Hydro | 2018 |
| Salkadamna | Niger | Coal | 2020 |
| Combined cycle | Togo | Nat. Gas | 2020 |
| 200MW park | Senegal/The Gambia | Wind | 2016-2020 |
| 300MW park | Nigeria | Wind | 2016-2020 |
| 150MW park | Burkina Faso | Solar photovoltaic | 2016-2020 |
| 150MW park | Mali | Solar photovoltaic | 2016-2020 |

Table 63 - Priority production projects

to third parties is forbidden without prior written approval
ny duplication or transmission
Engineering S.A. A
This document is the property of Tractebel

* * *

2.8.2. Priority transmission projects

The development of the optimal development plan according to the macro-economic
parameters showed the interest of massively developing the hydroelectric projects in
West Africa but also to maintain a balanced energy mix in order to preserve a
reasonable development cost in all circumstances.

Moreover, the low cost overrun generated by a voluntary policy as regards
renewable energies could encourage the countries to invest in such resources.

It is consequently necessary to reinforce the grid system in order to allow the
optimization of the exchanges between the areas having hydroelectric, gas and
renewable resources.

Whatever the load, fuels price or actualization rates parameters considered, the
study concludes that the Guinea (Fomi) - Ivory Coast (Boundiali) project is always
a very important project for the area. This project should be regarded as a priority
project for 2018. In addition, upstream projects (Linsan-Fomi) and downstream
(Boundiali-Ferkessedougou-Bobo and Bobo-Ouagadougou) should be
reinforced.

The reinforcement of the lines allowing the export of the energy produced in Guinea,
in Sierra Leone and Liberia will be all the more important as many hydroelectric
projects will be invested in these countries and that the neighbouring countries will
develop less projects at national level. Thus, the reinforcement of the CLSG line
could become crucial in the long term (>2020).

Moreover, considering the importance of also developing the gas resources in the
countries in the South of zoneA, the Coastal backbone will be a critical link which
could require a reinforcement in the long term (>2020).

Moreover, several transmission projects are directly associated with production
projects considered to be priority based on economic criteria.

The Median backbone would allow sharing the production of Zungeru between the
different countries of the region.

In the majority of the scenarios considered, the OMVS interconnection between
Linsan and Manantali is justified economically only by the presence of important
hydroelectric sites (Balassa, Koukoutamba, Boureya) on its routing. Nevertheless,
each one of these projects is so interesting that this line should be built in priority.

to third parties is forbidden without prior written approval
ny duplication or transmission
Engineering S.A. A
This document is the property of Tractebel

* * *

The table below shows the principal transmission developments selected by the
optimization tool based on purely economic criteria, in addition to the decided and
planned projects. Moreover, the lines which are justified by their associated regional
projects are indicated in italic.

| Name | Associated production project | Commissioning | Capacity |
| --- | --- | --- | --- |
| Median backbone | Zungeru | >2020 | 300MW |
| Liberia(Monrovia)-Ivory Coast(San Pedro) | Tiboto | 2018 | 150MW |
| OMVS-OMVG interconnection(Tambacounda-Kayes) | Gouina | 2017 | 250MW |
| OMVS-OMVG interconnection(Linsan-Manantali) | Koukoutamba,Boureya,Balassa | 2018 | 250MW |
| Guinea(Fomi)-Ivory Coast(Boundiali) |  | 2018 | 2x250MW |
| Linsan-Fomi(second line) | Souapiti | 2018 | 250MW |
| Boundiali-Ferke-Bobo(second circuit) |  | 2018 | 250MW |
| Bobo-Ouaga(second line) |  | 2018 | 250MW |
| Ligne CLSG(second circuit) |  | >2020 | 250MW |
| Coastal backbone sectionLome-Sakété(second line) |  | >2020 | 312MW |
| Salkadamana-Niamey | Salkadamna | 2020 | 200MW |
| Salkadamana-Center East | Salkadamna | 2020 | 100MW |

Table 64 - Priority transmission projects

to third parties is forbidden without prior written approval
ny duplication or transmission
Engineering S.A. A
This document is the property of Tractebel

* * *

3. TRANSMISSION NETWORK PERFORMANCES
   AND STABILITY ANALYSIS

3.1. Introduction

The economic analysis aims at providing a list of priority investments. The objective
of the stability study is to determine whether these investments will lead to a stable
operation of the network or if additional measures have to be taken to stabilize it. If
such measures are needed, their impact must be taken into account in the priority
investment list.

To this purpose, a complete model of the WAPP‟s system for the years 2015, 2020
and 2025 was built and different scenarios were investigated. The examined system
configurations varied on the availabilities of the interconnections between countries,
leading to different production units‟ commitment and international exchanges.

On these scenarios, multiple simulations were carried out to test the system and
assess its stability limits. The analysis covered static and dynamic aspects: security
analysis, operation optimization, reactive compensation study, short-circuits study,
small signal stability, transient stability and dynamic security assessment. All these
simulations revealed the weaknesses of the system and permitted to conclude on
how to extend its operation limits up to the desired level.

This chapter presents the results and conclusions of the transmission network
performances and stability analysis. At first, the methodology used for modeling the
network and performing the simulations is explained. Secondly, all details and
assumptions done for modeling the WAPP‟s interconnected network are given. Then
the different scenarios and the various simulations are presented. Finally, the
analysis is concluded and the impact on the investment priorities is assessed.

3.2. Methodology

This section explains the methodology for all simulations performed later here
below. The static analysis is depicted before the dynamic analysis.

3.2.1.1. OPTIMAL POWER FLOW AND REACTIVE COMPENSATION

to third parties is forbidden without prior written approval
ny duplication or transmission
Engineering S.A. A
This document is the property of Tractebel

* * *

3.2.1.1.1. Optimal power flow (OPF)

This first optimization is carried out using only the existing elements of the system.
The objective of the optimization is twofold:

• Improving the initial state by reducing the number of nodes violating the normal
voltage range. For this step, there is no objective function and the OPF is trying
to respect all the grid constraints (this step is called “feasibility step”).
Improving further the operation point by reducing reactive generation and

• Improving further the operation point by reducing reactive generation and
increasing the reactive margin of generators. This operating point is then used to
perform the different system analysis.

3.2.1.1.1.1. Definition of the optimization process

The optimization problem consists of three key features:

• The objective function which represents the operating performances of the power
system;

• The set of variables: state ( x) and control ( u) variables;

• The set of equality and inequality constraints.

3.2.1.1.1.2. Objective function

The objective consists of the maximization of the individual reactive margin of each
generator. This objective function characterizes the system security

f(x,u)!=!\\sum\_{i\\in!G}\\frac{\\left(Q\_{g,i}-Q\_{g0,i}\\right)^{2}}{Q\_{g,\\mathrm{m a x},i}-Q\_{g,\\mathrm{m i n},i}}

This objective function is aimed at meeting voltage security requirements.
Simulations have shown that these requirements are adequately reflected when the
individual reactive margin of each generating unit is maximized.

For closely located units, this objective function translates into similar reactive
power loading with regards to their reactive power limits.

Variables are divided into two groups: state ( x) and control ( u) variables. The state
variables correspond to all complex bus voltages. The control variables are related to
quantities used to “manipulate” (or control) the state variables. They consist of:

• Limits on state variables: voltage magnitudes (in general +/- 5%) and thermal
ratings of branches;
• Limits on control variables (Maximum and minimum reactive power of

• Reactive power of shunt capacitor /inductors. All compensation means are
assumed controllable.

• Transformer‟s tap positions. All transformers are supposed to be OLTC.
Reactive power of shunt capacitor /inductors. All compensation means are

to third parties is forbidden without prior written approval
ny duplication or transmission
Engineering S.A. A
This document is the property of Tractebel

* * *

3.2.1.1.2. Reactive power compensation

This second optimization consists in completing the existing resources of the system
with capacitor banks or reactor banks, to better manage the reactive power and the
voltages in the system. The reasons invoked for such installations are usually all
related:

• Compensating the load and improving the power factor;
Unload a line or a transformer by decreasing the reactive power flowing through,

• Unload a line or a transformer by decreasing the reactive power flowing through,
leaving more capacity for transiting active power;
Better controlling the voltages;

• Better controlling the voltages;

• Adjust the reactive power production of generating units.

3.2.1.2. SECURITY ANALYSIS

The objective of the security analysis is to estimate the ability of the network to
operate in case of contingencies.

This static analysis covers the disconnection of all branches (lines and transformers)
in the system. The loss of generating units will be analyzed dynamically as such
contingency require the simulations of dynamic phenomena (frequency deviation,
primary response of machine …).

For this analysis, the lines and transformers that are considered for contingency are
all connected at high voltage, from 760 to 90 kV.

When a branch is lost, two types of problem can appear, caused by the new power
flows in the network when it has reached its new steady state (dynamic behavior is
not taken into account for the static security analysis): branch overloads and voltage
variations (either under-voltage or over-voltage). The following criteria have been
defined:

Branch overloads criteria

• Initial load flow, before contingency, shouldn‟t show any branch overload
After contingency, the following overloading are accepted :

• After contingency, the following overloading are accepted :
-Lines and cables : 110%

-Lines and cables : 110%
-Transformers : 120%

3.2.1.3. SHORT-CIRCUIT ANALYSIS

Voltage variations criteria

-Transformers : 120%
Voltage variations criteria

• In the initial voltage profile, the voltage of every node in the network is between
0.95 pu and 1.05 pu
After contingency, the range tolerated is 0.9 pu to 1.1 pu

• After contingency, the range tolerated is 0.9 pu to 1.1 pu

to third parties is forbidden without prior written approval
ny duplication or transmission
Engineering S.A. A
This document is the property of Tractebel

* * *

The current measured must be less than the opening capability of the installed
equipment. These capabilities were not available in the data collection and are
consequently assumed to be:

• 31.5 kA for 161 kV, 225 kV, 330 kV and 760 kV breakers
25 kA for 90 kV, 110 kV, 132 kV and 150 kV breakers

• 25 kA for 90 kV, 110 kV, 132 kV and 150 kV breakers
The analysis is performed at peak load, and twice for each scenario: once with the

The analysis is performed at peak load, and twice for each scenario: once with the
generation units‟ commitment corresponding to the scenario and once with all
generating units connected. This last configuration is the one providing the
maximum values of short-circuit currents.

3.2.2. Dynamic analysis

3.2.2.1. SMALL SIGNAL STABILITY

The small signal stability assesses the damping level of the system oscillations.
The goal is to detect the eventual poorly damped oscillations and to study how to
improve the system behavior to such disturbances.

The future interconnected system of West Africa will be characterized by several
blocks connected together by relatively long AC lines. This type of structure is
likely to face problems of inter-area oscillations. This analysis will detect such
inter-area oscillations modes which could appear between the various parts of
the network.

3.2.2.1.1. Theoretical bases

3.2.2.1.1.1. Linear phenomena

Small signal stability concerns the study of the small fluctuations around an
operating point. The small fluctuations are caused through the slight disturbances
that occur at any time in a network (as a result of switching of loads, control
actions …). These disturbances differ essentially from those considered in
transient, voltage or frequency stability studies, since in the latter cases the
disturbances have larger amplitudes.

This analysis of small fluctuations is performed by the linearization of the
equations that describe the system. This approach is based on the assumption
that the non-linear system can be accurately approximated by a linear system for
small fluctuations.

It must be observed that small system stability is a necessary condition for the
operation of a power system.

to third parties is forbidden without prior written approval
ny duplication or transmission
Engineering S.A. A
This document is the property of Tractebel

* * *

3.2.2.1.1.2. Absolute stability criterion

The study of linear systems supplies an absolute stability criterion: the
eigenvalues are identified and verification is made that all their real parts are
negative.

Indeed, in response to a disturbance, there is an exponential that relates to each
eigenvalue. If the real part of one of these eigenvalue is positive, the exponential
will be increasing and the system will be unstable.

3.2.2.1.1.3. Evaluation of damping

When the system is stable, the analysis of the eigenvalues indicates the degree of
damping of the system. The requirement thereby is that the phenomena get
damped rapidly enough.

Given the uncertainties regarding some parameters, the cases where the real part
of an eigenvalue would be close to zero, either negative or positive, would be
considered unacceptable, although purely mathematically the first would be
stable while the second would not.

Generally, the system will be considered stable when there is a sufficient
stability margin (the real part is sufficiently negative). In the present study, the
steady state stability will be checked for various operating conditions.

3.2.2.1.1.4. Transfer functions and dominant modes

There are many eigenvalues in a large system. To each eigenvalue relates a
degree of damping and an oscillation frequency. The whole forms a “specific
operating mode”.

As a first approximation, the specific operating modes can be classified into four
groups:

• the inter-area modes: their frequency is generally comprised between 0.1 and 1
Hz, they relate to the natural oscillations between set of units forming together
coherent electrical areas;
the electromechanical modes: their frequency is around 1 Hz and they relate to

• the electromechanical modes: their frequency is around 1 Hz and they relate to
the natural oscillations of the generating units;
• the modes relating to the damper windings: they are highly damped;

• the other modes: they cannot be related directly to any precise cause.

3.2.2.1.2. Methodology

• the modes relating to the damper windings: they are highly damped;
• the modes relating to control systems (speed or voltage): these can be found

• the modes relating to control systems (speed or voltage): these can be found
within the entire frequency range, depending on the characteristics of the
systems;
the other modes: they cannot be related directly to any precise cause.

to third parties is forbidden without prior written approval
ny duplication or transmission
Engineering S.A. A
This document is the property of Tractebel

* * *

The study will be focused on the modes having a frequency equal or lower than
1.5 Hz that means the range of inter-area oscillations and electromechanical
modes. The oscillation modes will be determined and their damping will be
1.
compared with the international standards applied in that field

1
The "task force" CIGRE about the oscillations in networks recommends a
minimum damping of 5 %. This threshold of 5% for the damping will be
considered in the following analysis as the minimum level to be respected.

3.2.2.1.3. Modal analysis

3.2.2.1.3.1. Eigenvalues computations

For each mode, the following parameters were evaluated:

• Oscillation frequency of the mode:

f={\\frac{\\omega}{2\\pi}}

• Its damping defined as follows :

\\zeta!=!-!\\sigma/\\sqrt{!^{2}!+!\\omega^{2}}

where σ (resp. ω) is the real (resp. imaginary) part of the eigenvalues σ ± jω
associated to that particular mode. The damping makes it possible to determine
the number of cycle necessary to damp the related oscillations. One can show that
a damping of 37% (1/e) is reached after 1/(2 π ζ) cycles;

\ {bf sigma\\pm}

• A classification of the generating units according to the module of the right
eigenvector. They are thus classified according to their contribution to the mode
of oscillation considered.

3.2.2.2. TRANSIENT STABILITY

Transient stability condition is ensured when the system is able to withstand the
consequences of a severe disturbance and to return to stable steady state service (in
other words, withstand the fault avoiding the loss of synchronism of one or more
unit).

The transient stability analyses are performed through time domain dynamic
simulations. The critical fault clearing time (CCT), always given for a specific
location in the network, is defined as the longest admissible fault at this location to
avoid the loss of synchronism of one generator (or a whole power plant) with
respect to the system. It is what we define as the “classical” or “intrinsic” critical
clearing time which means that they do not include the action of the protective
systems.

1
The study "Analysis and Control of Power System Oscillations", Task force 07, Study Committee
38, December 1996 will be used like reference in this field. The practice of various
owners’ networks in the world is exposed there.

to third parties is forbidden without prior written approval
ny duplication or transmission
Engineering S.A. A
This document is the property of Tractebel

* * *

In terms of transient stability, the most severe fault is a 3-phase fault at the HV
connection node without faulted line reclosing. Most critical locations are generally
HV terminals of generating units as the units‟ acceleration is maximum during the
fault. The residual voltage in case of 2-phase or 1-phase faults being much higher
than the 3-phase fault, their related CCT‟s are higher than the ones computed by for
a 3-phase fault.

In order to compute the CCT, the synchronism of the generating units is evaluated
within a few seconds following the clearing of the fault. Stability on longer term is
not taken into account to compute the Critical Clearing Time. This must be kept in
mind because other phenomena such as the non-recovery of the voltage may induce,
on longer term, changes in the machines speed.

It also has to be noticed that for operating conditions close to peak conditions, the
system is usually facing voltage collapse before having loss of synchronism
problems. This is due to the high proportion of induction motors (AC) in the load at
peak conditions. To be focused on transient stability and risk of loss of synchronism,
a standard impedant load model is used for the entire network.

The load model is written:

\\begin{array}{r l}{\\bullet}&{{}P\_{i}(t)=P\_{0}\\left(\\frac{U}{U\_{0}}\\right)^{2}\\left(\\frac{\\omega}{\\omega\_{0}}\\right)^{\\gamma},,\\mathrm{w h e r e},\\gamma=0}\\end{array}

\\begin{array}{r l}{\\bullet}&{{}Q\_{i}(t)=Q\_{0}\\left(\\frac{U}{U\_{0}}\\right)^{2}\\left(\\frac{\\omega}{\\omega\_{0}}\\right)^{\\delta},,\\mathrm{w h e r e};\\delta=0}\\end{array}

3.2.2.3. DYNAMIC SECURITY ASSESSMENT

The methodology used to carry out the dynamic security analysis consists in
simulating different scenarios: short-circuit on lines, unit contingencies and power
transfer between areas.

For these simulations, several criteria are checked to verify the ability of the system
to withstand the transients and to recover to a stable steady-state:

• No machine loses synchronism

• No machine protection (under and over voltage, under and over frequency) is
activated.
For all nodes, all voltages recover above 0.7 pu. This helps checking no voltage

3.2.2.3.1. Three phase short-circuits

• For all nodes, all voltages recover above 0.7 pu. This helps checking no voltage
collapse occurs anywhere in the network.
• At steady-state, the voltage recovers between 0.9 pu and 1.1 pu.

• At steady-state, the voltage recovers between 0.9 pu and 1.1 pu.

• The frequency of the system does not drop below 49.5 Hz, first stage of the
UFLS as indicated in the WAPP Operation manual. At steady-state, the
frequency recovers between 49.8 Hz and 50.2 Hz.

to third parties is forbidden without prior written approval
ny duplication or transmission
Engineering S.A. A
This document is the property of Tractebel

* * *

Also, the interconnections are concerned by such simulations and it will be verified
that the various parts of the system are able to support the transient and recover to a
stable state.

3.2.2.3.2. Loss of generating units

A machine contingency is a likely incident that has to be supported by the system.
To check this, for all operating areas, all machines contingencies were simulated:
generators, and SVC.

The frequency deviation provoked by such contingencies is observed and
recommendations, among others on the UFLS tuning, will be issued based on these
observations.

3.2.2.3.3. Maximum transfer capacities

The maximum transfer capacities were determined for all interconnections between
countries.

They concern only active power and they are based on dynamic stability criteria, not
on static criteria, or ratings of equipments. The limit is reached when the system
becomes unstable due to:

1. A frequency collapse

2. A voltage collapse and/or motor stalling

3. A voltage collapse and/or motor stalling

4. A loss of synchronism

5. A loss of synchronism
   Since the stability during and after a three phase fault is considered as a design and


Since the stability during and after a three phase fault is considered as a design and
operation criterion, it is here checked that the system can support three phase faults
at the interconnection extremities.

The transit on the interconnection lines is increased by turning on generators in one
operating area and increasing the load in another operating area.

3.3. Assumptions and model construction

This section presents the construction of the PSA model of the WAPP‟s network.

First it is necessary here to emphasize that the objective of the study is to look at the
West African network in case of interconnections and electricity exchanges. The
study examines the system behavior and the interactions between its different parts
at high voltage level. It does not look into details at low voltage levels inside the
national networks. Solely the elements prone to have an interaction at high voltage
levels were modeled.

This section starts by summarizing, for each country, the detail level and the
elements that were modeled. Then, the second part of the section gives more details
of the model.

to third parties is forbidden without prior written approval
ny duplication or transmission
Engineering S.A. A
This document is the property of Tractebel

* * *

3.3.1.1. SENEGAL

Today Senegal‟s electrical system is linked to Mali through a 225 kV line
connecting the substations Kayes (Mali) to Matam (Senegal). It operates its
transmission network in 225 and 90 kV.

The OMVG project will interconnect Senegal to Gambia, Guinea and Guinea-Bissau
by a 225 kV line. The goal is to share the energy produced by Kaleta and
Sambangalou power plants. This project has 2 phases:

• Phase 1: Interconnection along the coast in 225 kV
Phase 2: Interconnection through the middle of the country in 225 kV, making a

• Phase 2: Interconnection through the middle of the country in 225 kV, making a
loop with phase 1.
Senegal‟s model includes the 225 and 90 kV voltage levels. The line Tobene-

Senegal‟s model includes the 225 and 90 kV voltage levels. The line Tobene-
Kounoune was considered operating in 225 kV in 2015 and the future loads were
connected to the nearest 90 or 225 kV substation.

3.3.1.2. THE GAMBIA

The Gambia‟s network is presently isolated from the rest of the WAPP‟s network.
They are foreseen to interconnect with the OMVG project.

Up to now, the highest voltage level in The Gambia is 33 kV. What occurs at this
voltage level will have little influence on the WAPP‟s interconnected system.

As a conclusion, the transmission network model in The Gambia covered the 225
kV OMVG network and an equivalent network was implemented in Brikama to
simulate the load and generation of the Greater Banjul Area.

3.3.1.3. GUINEA BISSAU

Guinea Bissau‟s network is presently isolated from the rest of the WAPP‟s network.
They are foreseen to interconnect with the OMVG project.

Up to now, the highest voltage level in Guinea Bissau is 30 kV. What occurs at this
voltage level will have little influence on the WAPP‟s interconnected system.

3.3.1.4. GUINEA

Guinea is presently isolated from the rest of the WAPP‟s network. It is foreseen to
interconnect with the implementation of many projects: OMVG, CLSG and Guinea-
Mali interconnections.

All these projects were modeled and Guinea was represented fully down to the 110
kV level, and partially at 60 kV level for the area of Conakry.

to third parties is forbidden without prior written approval
ny duplication or transmission
Engineering S.A. A
This document is the property of Tractebel

* * *

3.3.1.5. SIERRA LEONE

Presently, Sierra Leone‟s existing network is isolated from the rest of the WAPP‟s
network. It is foreseen to interconnect with the 225 kV CLSG project at Bumbuna.
From Bumbuna, an already existing 161 kV connection will link Freetown to the
WAPP‟s network.

As a conclusion, Sierra Leone was modeled from 225 kV to 161 kV. An equivalent
network was implemented to simulate the load and generation of Freetown.

3.3.1.6. LIBERIA

Presently, Liberia is isolated from the rest of the WAPP‟s network. It is foreseen to
interconnect with the 225 kV CLSG project. The interconnection will permit to
connect the capital city of Monrovia. Also the generation center of Buchanan will be
connected.

As a conclusion, Liberia was modeled from 225 kV to 161 kV. An equivalent
network was set up in Monrovia to simulate its load and generation.

3.3.1.7. MALI

Mali is currently interconnected to Senegal‟s network by a 225 kV line. Its
transmission system is composed of 225 and 150 kV voltage levels. The distribution
level of 30 kV has a loop. Its network is concentrated in the south-west of the
country.

Three interconnections are foreseen and a fourth one is under study. Mali will be
connected to Ghana and Burkina Faso by a 225 kV line from Bamako (Mali) to
Bolgatanga (Ghana), passing through Sikasso (Mali) and Bobo Dioulasso (Burkina
Faso). The second interconnection will be with Ivory Coast, from Segou (Mali) to
Ferkessedougou (Ivory Coast) by a 225 kV line, connecting also Koutiala (Mali) and
Sikasso(Mali). The third one will be between Bamako (Mali) and Fomi (Guinea),
again through a 225 kV line. The interconnection under study is from Manantali
(Mali) to Linsan (Guinea).

• New line in 225 kV between Laboa, Boundiali and Ferkessedougou
Second line in 225 kV between Soubre, Taabo

It is foreseen to reinforce the interconnection with Ghana from Riviera (Ivory Coast)
to Prestea (Ghana) with a 330 kV line. Another new interconnection is foreseen with
Mali from Ferkessedougou (Ivory Coast) to Segou (Mali), going through Sikasso
and Koutiala (both in Mali), in 225 kV. Some internal reinforcements are also
foreseen:

3.3.1.8. IVORY COAST

The model has the 225 and 150 kV voltage levels. The existing 30 kV loop was not
modeled and its generation and load were equally split between Lafiabougou and
Balingue substations.

• Second line in 225 kV between Soubre, Taabo
Third line in 225 kV between Taabo and Azito

to third parties is forbidden without prior written approval
ny duplication or transmission
Engineering S.A. A
This document is the property of Tractebel

* * *

The model was made from 330 kV down to 90 kV level. The 90 kV was reinforced
in order to avoid lines and transformers overloads in the base case (the list of
reinforcements for this voltage level was not provided).

3.3.1.9. GHANA

Ghana‟s network is one of the most important of the WAPP, being connected to
Ivory Coast by a 225 kV line between Prestea (Ghana) and Azito (Ivory Coast) and
connected to Togo/Benin by two 161 kV lines between Asiekpe (Ghana) and Lome
Port (Togo). Although the generation is concentrated in the south, there are great
loads in the north of the country.

The following projects are foreseen to reinforce the electrical system:

• Interconnection with Ivory Coast in 330 kV from Riviera (Ivory Coast) to Prestea
(Ghana).
Interconnection with Togo/Benin in 330 kV from Volta (Ghana) to Sakete

• Interconnection with Togo/Benin in 330 kV from Volta (Ghana) to Sakete
(Benin), passing through Lome Port (Togo).
Interconnection with Burkina Faso from Bolgatanga (Ghana) to Ouagadougou

• Interconnection with Burkina Faso from Bolgatanga (Ghana) to Ouagadougou
(Burkina Faso) in 225 kV.
Interconnection between Ghana, Burkina Faso and Mali connecting Bolgatanga

• Interconnection between Ghana, Burkina Faso and Mali connecting Bolgatanga
(Ghana), Bobo Dioulasso (Burkina Faso), Sikasso (Mali) and Bamako (Mali)
substations in 225 kV.
Interconnection with Togo (through the north) connecting Bawku (Ghana) and

• Interconnection with Togo (through the north) connecting Bawku (Ghana) and
Dapaong (Togo) in 161 kV.
Connection between south and north of Ghana in 330 kV level (from Kumasi to

• Connection between south and north of Ghana in 330 kV level (from Kumasi to
Bolgatanga substation).
The 330, 225 and 161 kV voltage levels were modeled. The reinforcement of the

The 330, 225 and 161 kV voltage levels were modeled. The reinforcement of the
system in 161 kV up to 2020 was taken from Ghana‟s Transmission Master Plan
study.

To reinforce the electrical system, the following lines are planned to be built:

• 161 kV line between Ketou and Parakou (Benin)
• 161 kV line connecting Bembereke and Malanville (Benin)

3.3.1.10. TOGO AND BENIN

• 161 kV line connecting Bembereke and Malanville (Benin)
161 kV line between Kara and Dapaong (Togo)

• 161 kV line between Kara and Dapaong (Togo)
The model includes the 330 and 161 kV levels. The Maria Gleta Power Plant (450

to third parties is forbidden without prior written approval
ny duplication or transmission
Engineering S.A. A
This document is the property of Tractebel

* * *

3.3.1.11. BURKINA FASO

Burkina Faso‟s network is composed of long lines and several different voltage
levels. The system is connected to Ivory Coast by a 225 kV line.

Three interconnections are foreseen:

• Bolgatanga (Ghana) – Ouagadougou (Burkina Faso) in 225 kV.
Bolgatanga (Ghana) – Bobo Dioulasso (Burkina Faso) – Sikasso (Mali) –

• Bolgatanga (Ghana) – Bobo Dioulasso (Burkina Faso) – Sikasso (Mali) –
Bamako (Mali) in 225 kV.
Ougagadougou (Burkina Faso) – Niamey (Niger) in 330 kV.

• Ougagadougou (Burkina Faso) – Niamey (Niger) in 330 kV.
The system was modeled from 330 to 33 kV.

The system was modeled from 330 to 33 kV.

3.3.1.12. NIGER

Niger is currently interconnected with Nigeria only, at 132 kV level. It is foreseen to
increase the interconnection capacity with the North Core project between Nigeria,
Niger, Benin and Burkina Faso.

Moreover, Niger‟s grid is presently divided in four zones. In the planned projects, a
coal production in Salkadamna is located in the middle of the River Area, the
Centre-Eastern Area and the North Area. It is foreseen to accompany this
Salkadamna project with interconnections between the River Area in 330 kV and the
Centre-Eastern Area in 132 kV.

As a conclusion, Niger‟s network was modeled from 330 kV down to 132 kV. An
equivalent network simulated the load and generation in Niamey.

3.3.1.13. NIGERIA

Nigeria is the biggest country in the WAPP area. It operates its transmission network
in 330 and 132 kV, with 330 kV interconnections with Benin and 132 kV
interconnection with Niger.

3.3.2. Static model

It is foreseen to start up a 760 kV super grid inside Nigeria, and reinforce the
interconnections at 330 kV levels with the neighboring countries.

As a conclusion, Nigeria was fully modeled from 760 kV to 330 kV. The 132 kV
level was not modeled because of the small impact it will have on the other
countries. Only the 132 kV interconnections with Niger were taken into account.

to third parties is forbidden without prior written approval
ny duplication or transmission
Engineering S.A. A
This document is the property of Tractebel

* * *

3.3.2.1. LOAD

For each country, the data collected was used at best with the load forecast carried
out in the inception report to spread the load among the different substations
represented in the model.

The load levels considered correspond to peak load for 2015, 2020 and 2025. The
final load repartition by country is given in Table .

Table and Table 1 give more details on the load per region in Niger and Nigeria
respectively. This detail was done for Niger because there are four zones that are not
connected. In Nigeria, the system is so big that it is worth splitting the information
by zone.

The reactive power consumption was calculated so that all power factors are equal to
0.85 in 2015, and 0.9 in 2020 and 2025.

Finally, for off peak load situation, a ratio of 70% was used for all countries.

|  | 2015 | 2020 | 2025 |
| --- | --- | --- | --- |
| Country Name | Active power consumption MW | Active power consumption MW | Active power consumption MW |
| Senegal | 629 | 891 | 1172 |
| The Gambia | 94 | 135 | 163 |
| Guinea Bissau | 38 | 83 | 117 |
| Mali | 366 | 550 | 693 |
| Guinea | 287 | 340 | 405 |
| Sierra Leone | 110 | 170 | 217 |
| Liberia | 50 | 68 | 93 |
| Ivory Coast | 1247 | 1652 | 2142 |
| Burkina Faso | 239 | 345 | 491 |
| Ghana | 2113 | 2775 | 3675 |
| Togo | 279 | 425 | 600 |
| Benin | 299 | 420 | 593 |
| Niger | 195 | 260 | 336 |
| Nigeria | 11225 | 14983 | 20000 |
| Mauritania | 48 | 48 | 48 |
| Total | 17219 | 23145 | 30745 |
| Total WAPP area | 17171 | 23097 | 30697 |

Table 65 – Load repartition by country for the peak load models

to third parties is forbidden without prior written approval
ny duplication or transmission
Engineering S.A. A
This document is the property of Tractebel

* * *

|  |  | 2015 | 2020 | 2025 |
| --- | --- | --- | --- | --- |
| Country Name | Zone Name | Active power consumptionMW | Active power consumptionMW | Active power consumptionMW |
| Niger | River | 113 | 151 | 195 |
| Niger | Centre-East | 28 | 38 | 49 |
| Niger | East | 5 | 6 | 8 |
| Niger | North | 49 | 66 | 85 |
| Total Niger |  | 195 | 261 | 337 |

Table 66 – Load repartition by zone in Niger for the peak load models

|  |  | 2015 | 2020 | 2025 |
| --- | --- | --- | --- | --- |
| Country Name | Zone Name | Active power consumption MW | Active power consumption MW | Active power consumption MW |
| Nigeria | Lagos | 5224 | 6956 | 9282 |
| Nigeria | Benin | 804 | 1086 | 1452 |
| Nigeria | Enugu | 1954 | 2613 | 3489 |
| Nigeria | Bauchi | 760 | 1014 | 1353 |
| Nigeria | Kaduna | 1193 | 1593 | 2126 |
| Nigeria | Shiroro | 1290 | 1721 | 2298 |
| Total Nigeria |  | 11225 | 14983 | 20000 |

Table 17 – Load repartition by zone in Nigeria for the peak load models

3.3.2.2. GENERATION

Based on the inception report lists and the results of the economic study, all existing
generators and future generators projected for 2015, 2020 and 2025 were included in
the model. In case of power limitation and/or rehabilitation, the accurate level of
available power was taken into account.

3.3.2.3. TRANSPORT

The grid was modeled fully from 760 to 90 kV, except for Nigeria where the 132 kV
voltage level was only partially modeled (for the interconnections with Niger) given
its low influence on the rest of the WAPP area. At lower voltage levels, an
equivalent of the system was built.

The information collected from each country was used at best to reproduce the
existing system and complete it with future projects.

to third parties is forbidden without prior written approval
ny duplication or transmission
Engineering S.A. A
This document is the property of Tractebel

* * *

For 2015, two scenarios were studies. The first one, referred as the Base case,
considers the future projects limited to the expectations for 2015, with two
exceptions; the North Core interconnection and the OMVG phase 1 interconnection.
Such exceptions were made because of the interest they represent, for connecting a
country (The Gambia and Guinea Bissau for the OMVG interconnection), for
exporting the power of an important power plant (Kaleta for the OMVG
interconnection) or improving the transfer capacity and the stability (for the North
Core interconnection). Then a second scenario examines what the situation would be
in 2015 if the system‟s interconnections were limited to the most fragile situation.
These two scenarios will be further described below.

For 2020 and 2025, the future projects modeled correspond to the results of the
economic study.

3.3.3. Dynamic model

This section provides the information needed for building a dynamic model
complementary to the static model described here above.

3.3.3.1. LOAD

3.3.3.1.1. Dynamic load model

The distribution by substation and the amount of load used for dynamics simulations
are identical to the static model. Nevertheless, in order to obtain more realistic
results, the distribution character of the load was taken into account in the dynamic
model. The dynamic load structure is as the figure below.

This model represents a load characterized by a significant proportion of induction
motors connected downstream a step-down transformer and a distribution feeder.
The model includes:

• A shunt compensation connected at the secondary of the transformer;
A generic induction motor connected downstream the distribution feeder;

Figure 43 – Dynamic Load Model

• A distribution feeder modeled by an impedance;
A shunt compensation connected at the secondary of the transformer;

• A generic induction motor connected downstream the distribution feeder;
A resistive load connected downstream the distribution feeder.

• A resistive load connected downstream the distribution feeder.

to third parties is forbidden without prior written approval
ny duplication or transmission
Engineering S.A. A
This document is the property of Tractebel

* * *

The shunt compensation device connected to the transformer secondary is adjusted
to match the reactive power absorbed by the load model with the load flow one and
the distribution feeder is modeled as an impedance.

It was used standard values for the model characteristics since no information was
provided. These are shown in Table .

| Transformer |  |
| --- | --- |
| Min. Ratio(pu) | 0.9 |
| Max. Ratio(pu) | 1.21 |
| Time Cons.(s) | 20 |
| Loading(%) | 60 |
| Uref(pu) | 1.03 |
| Resistance(pu) | 0.005 |
| Leakage(pu) | 0.035 |
| Feeder |  |
| Voltage Drop(pu) | 0.01 |
| Ratio(X/R) | 0.5 |
| Load Mix |  |
| Motor Loading(%) | 100 |
| Rotating Load Prop.(%) | 40 |
| Inertia(MW s/MVA) | 0.5 |
| Efficiency | 0.95 |
| Rated Mech.Power(pu) | 0.87 |
| Starting Torque Cd(pu) | 0.77 |
| Maximal Torque(pu) | 2.3 |
| Nominal Speed(rpm) | 2959 |
| Starting Current Id(pu) | 5.6 |

A key factor of the load model is the proportion of AC motors. No information has
been communicated about the composition of the load. Thus, for the dynamic study,
it will be considered that the proportion of induction motors is 40% at peak load and
off peak load conditions.

3.3.3.1.2. Defense schemes

The dynamic load modeling covers also the defense schemes like Under Frequency
Load Shedding (UFLs) and Under Voltage Load Shedding (UVLS).

About UFLS, the information of the WAPP Operation Manual states that:

• 10% of the load must be shed when the frequency drops down to 49.5 Hz
20% of the load must be shed when the frequency drops down to 49.2 Hz

As no information was given about UFLS and UVLS by the different countries, it
was not modeled.

• 20% of the load must be shed when the frequency drops down to 49.2 Hz
The compliance of these settings with the dynamic behavior of the system will be
reviewed in the dynamic studies.

to third parties is forbidden without prior written approval
ny duplication or transmission
Engineering S.A. A
This document is the property of Tractebel

* * *

3.3.3.2. GENERATION

For generation units, accurate information was rarely collected. Usually, either this
information is very difficult to obtain, or it is inexistent (for future units for
example) or incomplete. For many countries, the information provided corresponds
to the assumptions done in previous studies.

As a matter of fact, a lot of assumptions were necessary to complete the dynamic
model. At first, it was tried to copy the information from existing generators whose
data were available. As a second choice, the Consultant assumed values based on
good practices and experience.

Given the size of the system and the dynamic influence of small units, units below 5
MW were not modeled dynamically. Their production behaves as a negative load.

Synchronous machines are represented by full models including saturation. Wind
farm are modeled by converters. The network counts five SVC (three for the CLSG
project and two in Ghana).

3.3.3.2.1. Dynamic parameters and controllers

The same job was done for controllers. They are all simplified controllers, either
from the international IEEE practices or from the standard library of
PSA/EUROSTAG.

Particular attention was given to respect the static or brushless character of the
voltage regulations. The latter were completed with limiters:

• Over excitation activates as soon as the excitation current reaches 103% of its
nominal value. The current is then limited to its nominal value.
The under excitation limits the reactive power absorption to 10% of the nominal

• The under excitation limits the reactive power absorption to 10% of the nominal
active power when the machine produces this nominal active power, and to 15%
when its production is 0 MW.
Finally, all power/frequency controllers are equipped with maximum power limiter.

Finally, all power/frequency controllers are equipped with maximum power limiter.
This ensures a proper reaction of the machine governors in case of frequency
transients.

• Over voltage protection: 1.2 pu for 500 ms
All these settings must be completed with a breaker action time of 100 ms when the

• Under speed protection: 47.5 Hz for 500 ms
• Over speed protection: 52.5 Hz for 500 ms

• Under voltage protection: 0.7 pu for 500 ms
Over voltage protection: 1.2 pu for 500 ms

3.3.3.2.2. Protections

The WAPP operation manual states that generation units must remain connected to
the grid for frequencies between 48.5 Hz and 51 HZ. The Consultant will comment
this range in view of the simulations results.

to third parties is forbidden without prior written approval
ny duplication or transmission
Engineering S.A. A
This document is the property of Tractebel

* * *

3.4. Simulations

This section presents the situations investigated and the simulations performed.
Three target years were examined: 2015, 2020 and 2025. The development of the
system was foreseen according to the information received during the data collection
and to the results of the economic study.

Scenarios studied are first described. Then simulations are presented and illustrated
for the different years.

The year 2015 considers two scenarios, depending on the development of the system
in terms of interconnections. The first scenario studies a situation where all countries
are interconnected while the second scenario is a variant where the interconnected
system is less robust. For 2015, simulations were performed at peak load and offpeak load, statically and dynamically. This approach permitted to detect all the
potential problems the actual interconnected system will meet during its
development towards a state where it is fully interconnected.

The years 2020 and 2025 were investigated statically, at peak load only. The goal is
here to detect the reinforcement needs the system will face in order to reach a stable
operation.

3.4.1. Scenarios

3.4.1.1. 2015 BASE CASE

Two different scenarios were considered in the study for 2015. They are described
here below. The differences between them rely mainly in the interconnections
available, provoking different exchanges levels between countries and different
production units‟ commitment.

The Base Case examines the WAPP‟s system operation with all countries
interconnected. The consumption corresponds to a 2015 peak load situation, as
described in Table , Table and Table 1.

The following interconnections are in service:

• Coastal backbone from Nigeria to Ivory Coast

-Ivory Coast-Mali (Ferkessedougou-Sikasso-Segou)
-Ghana-Burkina Faso (Bolgatanga-Ouagadougou)

• North-core between Burkina Faso, Niger, Benin and Nigeria
CSLG from Ivory Coast to Guinea passing through Liberia and Sierra Leone with

• CSLG from Ivory Coast to Guinea passing through Liberia and Sierra Leone with
the production of Kaleta.
OMVG to connect Guinea Bissau and The Gambia to Senegal and Guinea

-Ghana-Burkina Faso-Mali (Bolgatanga-Kodeni-Sikasso-Bamako)
The following interconnections and production sites are not available in this 2015

The following interconnections and production sites are not available in this 2015
situation:

-Ghana-Burkina Faso-Mali (Bolgatanga-Kodeni-Sikasso-Bamako)
The following interconnections and production sites are not available in this 2015

• OMVG branch from Linsan to Tambacounda interconnecting the hydro site of
Sambangalou. This production is consequently not yet operational.
Guinea-Mali with the hydro site of Fomi.

• Guinea-Mali with the hydro site of Fomi.

to third parties is forbidden without prior written approval
ny duplication or transmission
Engineering S.A. A
This document is the property of Tractebel

* * *

• Interconnection between River and Centre-Eastern areas in Niger to connect the
coal unit of Salkadamna.
Table 69 presents the balance for load, production and power exchanges between

Table 69 presents the balance for load, production and power exchanges between
countries for the Base Case, at peak load conditions. The load level is as described
above for a total of 17220 MW including the 48 MW export towards Mauritania.
The losses represent 2.3 % of the global load and are particularly high in Guinea
Bissau (15.8%) due to high power transit from Guinea to Senegal and The Gambia.
The balance column provides the global active power import/export balance:

• Guinea (with Kaleta), Ivory Coast, Ghana and Nigeria are the exporting
countries.
Benin exports thanks to Maria Gleta Combined Cycle.

• Benin exports thanks to Maria Gleta Combined Cycle.
Mali exports 20 MW thanks to Manantali and Felou hydro power plants, located

• Mali exports 20 MW thanks to Manantali and Felou hydro power plants, located
on its territory.
Burkina Faso, Togo, Senegal and Niger are the biggest importing countries in

• Burkina Faso, Togo, Senegal and Niger are the biggest importing countries in
absolute value. Relatively, Togo imports 82% of its electricity and Burkina Faso
75%.

| Country | Generation |  | Load |  | Losses | Balance |
| --- | --- | --- | --- | --- | --- | --- |
| MW | Mvar | MW | Mvar | MW | MW |  |
| Benin | 455 | 95 | 299 | 185 | 9 | 147 |
| Burkina Faso | 69 | 14 | 239 | 148 | 10 | -179 |
| Ivory Coast | 1354 | 310 | 1247 | 773 | 44 | 63 |
| The Gambia | 51 | 30 | 94 | 58 | 2 | -45 |
| Guinea bissau | 20 | 9 | 38 | 24 | 6 | -24 |
| Ghana | 2309 | 536 | 2114 | 1310 | 65 | 129 |
| Guinea | 528 | 106 | 287 | 193 | 18 | 223 |
| Liberia | 47 | 9 | 50 | 95 | 0 | -4 |
| Mali | 404 | 56 | 366 | 227 | 18 | 20 |
| Mauritania | 0 | 0 | 48 | 30 | 0 | -48 |
| Nigeria | 11649 | 2193 | 11225 | 6957 | 183 | 241 |
| Niger | 118 | 45 | 195 | 121 | 13 | -90 |
| Senegal | 473 | 216 | 629 | 390 | 20 | -176 |
| Sierra Leone | 83 | 17 | 110 | 100 | 4 | -31 |
| Togo | 59 | 14 | 279 | 173 | 8 | -228 |
| TOTAL | 17618 | 3649 | 17220 | 10783 | 399 | 0 |

To share this reserve among the system, each country has to be responsible for a part
of it. Such participation is here assumed to be determined by the weight of each
country in the global system load. This calculation is summarized in Table .

Table 69 – Power balance for the Base Case scenario (peak load)

Concerning the spinning reserve, it is sized to the loss of the biggest unit in the
WAPP area. That biggest unit is the combined cycle of Okpai (Kwale) in Nigeria,
composed of two gas turbines and one steam turbine, each one rated 178.5 MW.
Given the common mode between the gas turbines and the steam turbine, the loss of
one gas turbine provokes a power reduction on the steam turbine. Assuming the
plant is operated at its nominal level, the production loss corresponding to a
contingency of a gas turbine is 267.75 MW (one gas turbine rated power and half of
the steam turbine rated power).

For each country, the generation plan and the reserve allocation was determined by
the Consultant according to good practices.

to third parties is forbidden without prior written approval
ny duplication or transmission
Engineering S.A. A
This document is the property of Tractebel

* * *

| Country Name | Load MW | Reserve expected MW | Actual reserve MW |
| --- | --- | --- | --- |
| Senegal | 629 | 9.8 | 9.8 |
| The Gambia | 94 | 1.5 | 1.5 |
| Guinea Bissau | 38 | 0.6 | 0.6 |
| Guinea | 287 | 4.5 | 4.5 |
| Mali | 366 | 5.7 | 5.7 |
| Sierra Leone | 110 | 1.7 | 1.7 |
| Liberia | 50 | 0.8 | 0.8 |
| Ivory Coast | 1247 | 19.4 | 19.4 |
| Burkina Faso | 239 | 3.7 | 3.7 |
| Ghana | 2113 | 32.9 | 32.9 |
| Togo+Bénin | 578 | 9.0 | 9.0 |
| Niger | 195 | 3.0 | 3.0 |
| Nigeria | 11225 | 175.0 | 185.7 |
| Total | 17171 | 267.8 | 278.4 |

Table 70 – Spinning reserve per country

For the off peak load situation, a ratio of 70% was taken for all countries. The same
levels of spinning reserves were kept. The same exchanges patterns are also kept
though the levels of exchanges are lower.

| Country | Generation |  | Load |  | Losses | Balance |
| --- | --- | --- | --- | --- | --- | --- |
| MW | Mvar | MW | Mvar | MW | MW |  |
| Benin | 230 | -6 | 209 | 130 | 5 | 16 |
| Burkina Faso | 56 | -1 | 167 | 104 | 5 | -117 |
| Ivory Coast | 985 | 198 | 873 | 541 | 31 | 81 |
| The Gambia | 46 | 14 | 66 | 41 | 0 | -20 |
| Guinea bissau | 12 | 4 | 27 | 17 | 1 | -15 |
| Ghana | 1591 | 55 | 1480 | 916 | 34 | 77 |
| Guinea | 260 | 15 | 201 | 140 | 11 | 48 |
| Liberia | 32 | -1 | 35 | 86 | 1 | -4 |
| Mali | 244 | -1 | 256 | 159 | 8 | -20 |
| Mauritania | 0 | 0 | 30 | 20 | 0 | -30 |
| Nigeria | 8182 | 153 | 7858 | 4870 | 106 | 219 |
| Niger | 69 | -4 | 102 | 63 | 7 | -40 |
| Senegal | 393 | 154 | 441 | 273 | 6 | -54 |
| Sierra Leone | 58 | 1 | 77 | 80 | 2 | -21 |
| Togo | 78 | 0 | 195 | 121 | 3 | -120 |
| TOTAL | 12236 | 581 | 12017 | 7561 | 220 | 0 |

Table 71 - Power balance for the Base Case scenario (off peak load)

to third parties is forbidden without prior written approval
ny duplication or transmission
Engineering S.A. A
This document is the property of Tractebel

* * *

3.4.1.2. 2015 SCENARIO 2

Scenario 2 is a variant of the Base Case. It is also representing a 2015 situation but
the future production units and interconnections projects available are limited.

In comparison with the Base case, all projects expected for 2015 or later were
removed. This leads to a situation where:

• The Gambia and Guinea Bissau are not interconnected.
The WAPP network is a long interconnection from Niger to Senegal, with

• The WAPP network is a long interconnection from Niger to Senegal, with
Burkina Faso as one antenna and the CLSG countries as another one.
The absence of the North-core interconnection makes Niger connected only to

• The absence of the North-core interconnection makes Niger connected only to
Nigeria via the 132 kV level
The link between Ghana and Burkina Faso is limited to the 330 kV line from

• The link between Ghana and Burkina Faso is limited to the 330 kV line from
Bolgatanga to Ouagadougou but is not supported by the 330 kV north-south
project from Domini to Bolgatanga. Though the interconnection between Ivory
Coast and Burkina Faso is still in service, the latter is weakly interconnected
though it is the country with the biggest importation expectations.
• The 330 kV line between Ivory Coast and Ghana (Riviera-Prestea) is not in

• The 330 kV line between Ivory Coast and Ghana (Riviera-Prestea) is not in
service. Moreover, Burkina Faso is not connected to Mali. Mali is only
interconnected to Ivory Coast. As a consequence, the interconnection of Mali and
Senegal is reduced to the minimum: one line with Ivory Coast.
Guinea cannot count on any big hydro projects; neither Kaleta, nor Sambangalou

• Guinea cannot count on any big hydro projects; neither Kaleta, nor Sambangalou
nor Fomi are in service. Also Mount Coffee hydro power plant in Liberia is not
yet available. And as a matter of fact, Sierra Leone, Liberia and Guinea are
obliged to import electricity from Ivory Coast to complete their power balances.
Table lists all the interconnections and summarizes the status of each one of them

Table lists all the interconnections and summarizes the status of each one of them
for both scenarios. The existing interconnections are obviously in service. The 330
kV north-south project in Ghana is also indicated.

As a conclusion, the interest of this scenario is its fragility in terms of
interconnections. It is a realistic stage towards the objective of a global WAPP
interconnected system. The purpose of this scenario is to investigate the stability
challenges of such stage to foresee and prevent any limitations.

• Ivory Coast, Ghana and Nigeria are still exporting countries. Guinea, due to the
absence of Kaleta, imports power.
Benin exports thanks to Maria Gleta Combined Cycle.

• Mali exports 108 MW from Manantali hydro power plant to Senegal and
Mauritania. This export level is higher than for the Base case because the
interconnection with Burkina Faso and Ghana is not yet commissioned. With the
absence of Kaleta, and with Ivory Coast exporting already for the CLSG
countries, the export from Ghana to Mali has to pass through Ivory Coast,
limiting the transfer capacity.

• Benin exports thanks to Maria Gleta Combined Cycle.
Mali exports 108 MW from Manantali hydro power plant to Senegal and

to third parties is forbidden without prior written approval
ny duplication or transmission
Engineering S.A. A
This document is the property of Tractebel

* * *

• Burkina Faso, Togo, Senegal, Niger, Sierra Leone, Liberia and Guinea are the
importing countries. Relatively, Togo imports 70% of its electricity. For this
scenario, the import of Burkina Faso is limited to 21% due to weak
interconnections.

| Country | Generation |  | Load |  | Losses | Balance |
| --- | --- | --- | --- | --- | --- | --- |
| MW | Mvar | MW | Mvar | MW | MW |  |
| Benin | 475 | 107 | 298 | 185 | 10 | 167 |
| Burkina Faso | 198 | 45 | 239 | 148 | 9 | -50 |
| Ivory Coast | 1401 | 428 | 1247 | 773 | 56 | 98 |
| The Gambia | 0 | 0 | 0 | 0 | 0 | 0 |
| Guinea bissau | 0 | 0 | 0 | 0 | 0 | 0 |
| Ghana | 2279 | 663 | 2114 | 1310 | 69 | 95 |
| Guinea | 239 | 48 | 287 | 191 | 13 | -61 |
| Liberia | 39 | 5 | 50 | 51 | 7 | -17 |
| Mali | 492 | 69 | 366 | 227 | 18 | 108 |
| Mauritania | 0 | 0 | 48 | 30 | 0 | -48 |
| Nigeria | 11491 | 2024 | 11225 | 6957 | 188 | 78 |
| Niger | 166 | 68 | 195 | 121 | 11 | -40 |
| Senegal | 534 | 271 | 605 | 375 | 25 | -96 |
| Sierra Leone | 77 | 19 | 110 | 68 | 7 | -40 |
| Togo | 95 | 24 | 279 | 173 | 10 | -194 |
| TOTAL | 17486 | 3772 | 17063 | 10608 | 423 | 0 |

Table 72 - Power balance for Scenario 2 (peak load)

For the spinning reserve, the sizing incident is still the loss of one GT and half a ST
at Okpai (Kwale) combined cycle. It represents 267.75 MW.

In this scenario, the same reserve levels for each country are kept. The reserve part
initially assigned to Guinea Bissau and The Gambia is here supported by Nigeria.

For the off peak load situation, a ratio of 70% was taken for all countries. The same
levels of spinning reserves were kept. The same exchanges patterns are also kept
though the levels of exchanges are lower.

to third parties is forbidden without prior written approval
ny duplication or transmission
Engineering S.A. A
This document is the property of Tractebel

* * *

| Country | Generation |  | Load |  | Losses | Balance |
| --- | --- | --- | --- | --- | --- | --- |
| MW | Mvar | MW | Mvar | MW | MW |  |
| Benin | 230 | 47 | 209 | 129 | 8 | 13 |
| Burkina Faso | 66 | 12 | 167 | 104 | 5 | -106 |
| Ivory Coast | 1041 | 184 | 873 | 541 | 49 | 119 |
| The Gambia | 0 | 0 | 0 | 0 | 0 | 0 |
| Guinea bissau | 0 | 0 | 0 | 0 | 0 | 0 |
| Ghana | 1611 | 251 | 1480 | 916 | 51 | 80 |
| Guinea | 152 | 23 | 201 | 139 | 6 | -55 |
| Liberia | 32 | 6 | 35 | 83 | 4 | -7 |
| Mali | 279 | 46 | 256 | 159 | 10 | 14 |
| Mauritania | 0 | 0 | 30 | 20 | 0 | -30 |
| Nigeria | 8165 | 1186 | 7858 | 4870 | 118 | 189 |
| Niger | 81 | 19 | 102 | 63 | 11 | -32 |
| Senegal | 393 | 103 | 424 | 263 | 8 | -39 |
| Sierra Leone | 58 | 6 | 77 | 80 | 4 | -23 |
| Togo | 78 | 18 | 195 | 121 | 7 | -124 |
| TOTAL | 12186 | 1901 | 11906 | 7486 | 281 | 0 |

Table 73 - Power balance for Scenario 2 (off peak load)

to third parties is forbidden without prior written approval
ny duplication or transmission
Engineering S.A. A
This document is the property of Tractebel

* * *

| Substation 1 Name | Country 1 Name | Substation 2 Name | Country 2 Name | Voltage level kV | Project Name | Base case status | Scenario 2 status |
| --- | --- | --- | --- | --- | --- | --- | --- |
| Ikeja West | Nigeria | Sakete | Benin | 330 |  | existing |  |
| Sakete | Benin | Lome | Togo | 330 |  | existing |  |
| Elubo | Ghana | Abobo | Ivory Coast | 225 |  | existing |  |
| Matam | Senegal | Kayes | Mali | 225 |  | existing |  |
| Ferkedessougou | Ivory Coast | Kodeni | Burkina Faso | 225 |  | existing |  |
| Lome | Togo | Asiekpe | Ghana | 161 |  | existing |  |
| Lome | Togo | Aflao | Ghana | 161 |  | existing |  |
| Birim Kebbi | Nigeria | Niamey | Niger | 132 |  | existing |  |
| Gaza | Niger | Katsina | Nigeria | 132 |  | existing |  |
| Bawku | Ghana | Dapaong | Togo | 161 |  | existing 34.5 kV(on 161 kV in both scenarios) |  |
| Birim Kebbi | Nigeria | Niamey | Niger | 330 | Northcore | on | out |
| Birim Kebbi | Nigeria | Malanville | Benin | 330 | Northcore | on | out |
| Niamey | Niger | Ouagadougou | Burkina Faso | 330 | Northcore | on | out |
| Niamey | Niger | Malanville | Benin | 330 | Northcore | on | out |
| Lome | Togo | Volta | Ghana | 330 | Coastal backbone | on | on |
| Prestea | Ghana | Riviera | Ivory Coast | 330 | Coastal backbone | on | out |
| Sakete | Benin | Osogbo | Nigeria | 330 | Coastal backbone | out | out |
| Man | Ivory Coast | Yekepa | Liberia | 225 | CLSG | on | on |
| Mano | Liberia | Kenema | Sierra Leone | 225 | CLSG | on | on |
| Kamakwie | Sierra Leone | Linsan | Guinea | 225 | CLSG | on | on |
| Boke | Guinea | Saltinho | Guinea Bissau | 225 | OMVG | on | out |
| Mansoa | Guinea Bissau | Tanaf | Senegal | 225 | OMVG | on | out |
| Tanaf | Senegal | Soma | The Gambia | 225 | OMVG | on | out |
| Soma | The Gambia | Kaolack | Senegal | 225 | OMVG | on | out |
| Ferkedessougou | Ivory Coast | Sikasso | Mali | 225 | Inter zonal | on | on |
| Kodeni | Burkina Faso | Sikasso | Mali | 225 | Inter zonal | on | out |
| Kodeni | Burkina Faso | Bolgatanga | Ghana | 225 | Inter zonal | on | out |
| Nzerekore + Linsan | Guinea | Sikasso | Mali | 225 | Inter zonal | out | out |
| Bolgatanga | Ghana | Ouagadougou | Burkina Faso | 225 | Inter zonal | on | on |
| Aboadze | Ghana | Kumasi | Ghana | 330 | Inter zonal | on | out |

to third parties is forbidden without prior written approval
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

3.4.1.3. 2020

The 2020 scenario is based on the results of the economic study.

For what consumption concerns, the load level is the 2020 peak load. The reactive
power consumption was calculated using a power factor of 0.9, as recommended
after the 2015 analysis.

For what production concerns, the new investments recommended by the economic
study in terms of interconnection lines and power plants were modeled. In
comparison with the 2015 situation, the list of new projects includes:

• The interconnection line between Fomi (Guinea) and Boundiali (Ivory Coast)
The power plants in Table 752.

• The power plants in Table 752.
Based on that, the units commitment was chosen according to three different rules:

Based on that, the units commitment was chosen according to three different rules:

1. Starting the less expensive units first.

2. Approaching the average flows on the lines calculated by the economic study

3. Approaching the average flows on the lines calculated by the economic study
   since the goal of the technical study is to check the results of the economic
   study are technically feasible.

4. Starting the regional units first. For instance, the amount of investments in

5. Starting the regional units first. For instance, the amount of investments in
   Guinea, Sierra Leone and Liberia is very important. In the load flow, only a few
   units are running in these countries. The first reason is that it is impossible to
   have these countries export the whole power of all its units at maximum at the
   same time. The second reason is that many projects (Amarya, Mano River,…)
   are initially related to mines projects, so that their implementation might be
   more driven by the decision of operating mines than sharing the power for
   regional aspects. In particular, the regional projects of Kaleta, Sambangalou,
   Koukoutamba, Boureya, Balassa and Badoumbe were running. The projects of
   Digan, Nzebela and Franko were also running. All the other new hydro power
   plants in Guinea, Sierra Leone and Liberia were stopped.
   With the new units, reinforcements were needed to support the flows in N condition,


With the new units, reinforcements were needed to support the flows in N condition,
to evacuate this new power to the consumption centers and to absorb it in the
importing countries. Particularly:

• Reinforcements in Dakar. In addition to the 225 kV loop Tobene-Kounoune-
Sendou-Mbour-Kaolack-Touba, new 225 kV lines between Sendou and
Kounoune, new 225/90 kV transformers at Kounoune and new 90 kV lines
between Kounoune and Han are necessary to transit the power from Sendou to
the consumption of Dakar.
• The Gouina project is accompanied by a 225 kV line from Kayes to

• The Gouina project is accompanied by a 225 kV line from Kayes to
Tambacounda. The dynamic studies for 2015 have shown the importance of such
reinforcements to avoid the huge loop between OMVS-CLSG-OMVG. An
important loop remains but this link improves the situation.
• The Amarya project is accompanied by 225 kV lines from Kaleta to Amarya and

• The OMVS projects of Boureya, Balassa, Koukoutamba and Badoumbe imply to
create a line between Linsan and Manantali to connect them. The reinforcement
of the line between Manantali and Bamako are also necessary to evacuate the
power of these new units towards Mali and Burkina Faso. This line between
Linsan and Manantali is another important investment to improve the stability of
the area by reducing the huge loop OMVS-OMVG-CLSG.

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

• The project of Adajaralla implies new lines from the 161 kV substation of
Adjaralla towards Ava and Nangbeto.
The project of Ketou implies the reinforcement of the 161 kV line between

• The project of Ketou implies the reinforcement of the 161 kV line between
Onigbolo and Sakete.

• Reinforcements in Bamako‟s network are necessary for the 225/150 kV
transformer of Kodialani and for the 150 kV lines between Lafia and Kodialani
and between Kodialani and Kalaba Coro. Also the 150 kV line between Selingue
and Sirako should be reinforced because of the exports from Guinea towards
Mali and Burkina Faso on the 225 kV line from Fomi.
Reinforcements in Burkina Faso are necessary. The 225/90 kV transformer of

• Reinforcements in Burkina Faso are necessary. The 225/90 kV transformer of
Zagtouli must be doubled. The 33 kV lines between Ouagadougou, Patte d‟oie,
Zagtouli and Komsilga substations must also be doubled.
In Ivory Coast, the 90 kV lines between Abobo and Vridi must be doubled.

• In Ivory Coast, the 90 kV lines between Abobo and Vridi must be doubled.
The project of Aboisso Comoe requires reinforcing the 90 kV line between

• The project of Aboisso Comoe requires reinforcing the 90 kV line between
Abobo and Bongo.
A third 225/30kV transformer is installed in Bissau.

• A third 225/30kV transformer is installed in Bissau.
A third 225/33kV transformer is installed in Monrovia.

• A third 225/33kV transformer is installed in Monrovia.

Finally, the power balance for the 2020 peak load scenario is given in Table . The
most important fact is the 1000 MW export of hydro power from Guinea. This
power is absorbed by Guinea Bissau, The Gambia and Senegal thanks to the OMVG
interconnection. Part of it goes to Mali via Koukoutamba and via Fomi. Finally an
important part transits through the CLSG interconnection and via the line Fomi-
Boundiali to reach Burkina Faso.

Besides this important fact, Benin is exporting a bit thanks to the presence of Maria
Gleta, while Togo imports. Niger, with the apparition of Kandadji and Dyodyonga
dams, also exports slightly. Ghana imports slightly and Nigeria imports 170 MW
which is low in comparison with its national load, but important on the flows in the
area.

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

| Power plant | Power MW | Country | Substation | Voltage kV |
| --- | --- | --- | --- | --- |
| Sendou | 250 | Senegal | Sendou | 225 |
| Digan | 93 | Guinea | Labe | 225 |
| Amarya | 300 | Guinea | Amarya(Kaleta+Matoto) | 225 |
| Lafou | 98 | Guinea | Linsan | 225 |
| Kassa B | 135 | Guinea | Linsan | 225 |
| Koukoutamba | 281 | Guinea | Koukoutamba(Boureya+Linsan) | 225 |
| Boureya | 160 | Guinea | Boureya(Koukoutamba+Manantali) | 225 |
| Balassa | 181 | Guinea | Linsan | 225 |
| Kouya | 86 | Guinea | Mali | 225 |
| Fetore | 124 | Guinea | Labe | 225 |
| Kouravel | 135 | Guinea | Mali | 225 |
| Diareguela | 72 | Guinea | Koroussa | 225 |
| Nzebela | 48 | Guinea | Beyla | 225 |
| Grand Kinkon | 291 | Guinea | Labe | 225 |
| Bonkon Diaria | 154 | Guinea | Labe | 225 |
| Gozogueza | 48 | Guinea | Nzerekore | 225 |
| Franko | 36 | Guinea | Nzerekore | 225 |
| Poudadle | 90 | Guinea | Boke | 225 |
| Gouina | 140 | Mali | Kayes | 225 |
| Markala | 10 | Mali | Ségou | 225 |
| Badoumbe | 70 | Mali | Badoumbe(Manantali) | 225 |
| Bonkongor | 85.5 | Sierra Leone | Bikongor | 225 |
| Bumbuna 3 | 90 | Sierra Leone | Yiben | 225 |
| Bumbuna 4-5 | 95 | Sierra Leone | Bumbuna | 225 |
| Mano river | 180 | Liberia | Mano | 225 |
| Boutoubre | 156 | Ivory Coast | Soubre | 225 |
| Soubre | 270 | Ivory Coast | Soubre | 225 |
| Aboisso comoe | 90 | Ivory Coast | Bong(Abobo) | 90 |
| Tiboto | 225 | Ivory Coast-Liberia | Tiboto(Soubre) | 225 |
| Hemang | 93 | Ghana | Cape Coast | 330 |
| Pwalugu | 48 | Ghana | Bolgatanga | 225 |
| Juale | 87 | Ghana | Yendi | 161 |
| Ketou | 160 | Benin | Onigbolo(Sakete) | 161 |
| Adjaralla | 140 | Togo | Adjaralla(Ava+Nangbeto) | 161 |
| Dybodyonga | 26 | Niger | Niamey | 132 |
| Kandadji | 130 | Niger | Kandadji(Niamey) | 132 |
| Zungeru | 700 | Nigeria | Zungeru(Jebba+Shiroro) | 330 |
| Mambilla | 2600 | Nigeria | Mambilla | 760 |

Table 752 – New power plants for year 2020

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

| Country | Generation |  | Load |  | Losses | Balance |
| --- | --- | --- | --- | --- | --- | --- |
| MW | Mvar | MW | Mvar | MW | MW |  |
| Benin | 455 | 133 | 420 | 204 | 11 | 24 |
| Burkina Faso | 88 | 17 | 342 | 166 | 18 | -272 |
| Ivory Coast | 1812 | 502 | 1652 | 800 | 108 | 52 |
| The Gambia | 45 | 49 | 135 | 65 | 1 | -91 |
| Guinea Bissau | 35 | 16 | 83 | 40 | 6 | -54 |
| Ghana | 2828 | 620 | 2775 | 1343 | 67 | -15 |
| Guinea | 1445 | 156 | 340 | 180 | 62 | 1043 |
| Liberia | 91 | 10 | 68 | 93 | 4 | 19 |
| Mali | 585 | 100 | 550 | 266 | 104 | -69 |
| Mauritania | 0 | 0 | 48 | 23 | 0 | -48 |
| Nigeria | 15128 | 2372 | 14983 | 7257 | 312 | -168 |
| Niger | 297 | 56 | 260 | 126 | 10 | 27 |
| Senegal | 635 | 239 | 891 | 431 | 34 | -290 |
| Sierra Leone | 99 | 21 | 170 | 114 | 10 | -82 |
| Togo | 360 | 26 | 425 | 206 | 11 | -76 |
| TOTAL | 23903 | 4317 | 23143 | 11314 | 758 | 0 |

Table 76 - Power balance for 2020 peak load scenario

3.4.1.4. 2025

The 2025 scenario is based on the results of the economic study.

For what consumption concerns, the load level is the 2025 peak load. The reactive
power consumption was calculated using a power factor of 0.9, as recommended
after the 2015 analysis.

Table 77 – New power plants for year 2025

For what production concerns, the new investments recommended by the economic
study in terms of interconnection lines and power plants were modeled. In
comparison with the 2020 situation, the list of new projects includes the power
plants listed in Table . There is no new interconnection project.

| Power plant | Power MW | Country | Substation | Voltage kV |
| --- | --- | --- | --- | --- |
| Gribopopoli | 112 | Ivory Coast | Soubre | 225 |
| St Paul | 192 | Liberia | St Paul (Monrovia) | 225 |
| SAP | 200 | Ghana | Asogli | 161 |
| BTPP | 250 | Ghana | Smelter 2 | 161 |
| CEM Power | 250 | Ghana | Smelter 2 | 161 |
| Salkadamna | 200 | Niger | Salkadamna | 330 |
| Lome CC | 450 | Togo | Lome | 161 |
| Ethiopie | 1200 | Nigeria | Benin City North | 330 |

With the new units, reinforcements are needed to support the flows in N condition,
to evacuate this new power to the consumption centers and to absorb it in the
importing countries. Table and Table 793 list the lines and transformers
reinforcements needed.

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

These reinforcements are the minimum to implement in order to cover the flows in
N condition. N-1 is not covered and will be studied further below.

On a regional level, the reinforcements of the lines between Manantali, Tkita,
Kodialani and Sikasso, and between Soubre and Taabo are of utmost importance for
evacuating the hydro power to the East.

| Country Name | Substation 1 Name | Substation 2 Name | Voltage level kV |
| --- | --- | --- | --- |
| Burkina Faso | Bobo 1 | Bobo 2 | 33 |
| Burkina Faso | Zagtouli | Ouagadougou | 90 |
| Ivory Coast | Yopougnon | Vridi | 90 |
| Ivory Coast | Vridi | Bia sud | 90 |
| Ivory Coast | Daloa | Buyo | 90 |
| Ivory Coast | Soubre | Taabo | 225 |
| Mali | Manantali | Tkita | 225 |
| Mali | Tkita | Kodialani | 225 |
| Mali | Kodialani | Sikasso | 225 |
| Nigeria | Ikeja West | Akangba | 330 |
| Nigeria | Ikeja West | Erunkan | 330 |
| Nigeria | Owerri | Alaoji | 330 |
| Nigeria | Omtosho | Benin City | 330 |
| Senegal | Sococim | Thiona | 90 |

Table 78 – Lines reinforcements needed in 2025

| Country Name | Substation Name | Voltage levels |  |
| --- | --- | --- | --- |
|  |  | kV | kV |
| Nigeria | Egbema | 760 | 330 |
| Sierra Leone | Bumbuna | 225 | 161 |
| Ivory Coast | Laboa | 225 | 90 |
| Ivory Coast | Abobo | 225 | 90 |
| Ivory Coast | Ferkessedougou | 225 | 90 |
| Guinea | Matoto | 110 | 60 |
| Guinea | Matoto | 110 | 60 |
| Ivory Coast | Taabo | 225 | 90 |
| Burkina Faso | Zagtouli | 90 | 33 |
| Burkina Faso | Zagtouli | 90 | 33 |
| Ivory Coast | Buyo | 225 | 90 |

Finally, the power balance for the 2025 peak load scenario is given iTable n Table .
As in 2020, there are 1000 MW export of hydro power from Guinea. This power is
still absorbed by Guinea Bissau, The Gambia and Senegal thanks to the OMVG
interconnection, by Mali via Koukoutamba and via Fomi and by Burkina Faso
through the CLSG and the Fomi-Boundiali interconnections.

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

| Country | Generation |  | Load |  | Losses | Balance |
| --- | --- | --- | --- | --- | --- | --- |
|  | MW | Mvar | MW | Mvar | MW | MW |
| Benin | 465 | 160 | 593 | 287 | 14 | -142 |
| Burkina Faso | 246 | 53 | 490 | 236 | 34 | -278 |
| Ivory Coast | 2509 | 961 | 2142 | 1037 | 164 | 203 |
| The Gambia | 75 | 29 | 163 | 79 | 1 | -89 |
| Guinea Bissau | 70 | 13 | 117 | 57 | 6 | -53 |
| Ghana | 3624 | 1166 | 3674 | 1779 | 97 | -146 |
| Guinea | 1393 | 53 | 405 | 211 | 50 | 937 |
| Liberia | 201 | 24 | 93 | 75 | 14 | 94 |
| Mali | 672 | 10 | 693 | 336 | 128 | -149 |
| Mauritania | 0 | 0 | 48 | 23 | 0 | -48 |
| Nigeria | 20330 | 4054 | 20000 | 9686 | 536 | -206 |
| Niger | 174 | 59 | 252 | 122 | 4 | -82 |
| Senegal | 974 | 307 | 1172 | 568 | 41 | -239 |
| Sierra Leone | 301 | 12 | 217 | 137 | 8 | 77 |
| Togo | 732 | 104 | 600 | 291 | 10 | 122 |
| TOTAL | 31766 | 7005 | 30659 | 14923 | 1107 | 0 |

Table 80 - Power balance for 2025 peak load scenario

3.4.2. Static studies: Voltage management and reactive
compensation

The voltage management and reactive compensation study optimizes the
transformers tap position, capacitor and reactor bank step position, voltage set point
of generators and reactive output of units. It is obtained by optimal power flow
respecting all operational constraints (thermal capacity of lines and transformers,
voltage profile in the +/-5% range) and optimizing the alignment of the reactive
generation of the units.

The objective of aligning the reactive generation of the units is to maximize the
reserves of reactive power. The essential advantage of this objective function is its
determination of the best “mean” system voltage not depending of the system
situation.

3.4.2.1. 2015

The system study at peak load showed that reactive compensation was necessary to
respect the operation criteria. Table shows all shunts to be implemented to respect
the operation criteria in the Base case and Scenario 2 for peak load situations.

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

| Node Name | Country Name | Voltage kV | Steps # | Rating Mvar/step | Capacity Mvar |
| --- | --- | --- | --- | --- | --- |
| Ikeja | Nigeria | 330 | 5 | 100.0 | 500.0 |
| Akangbe | Nigeria | 330 | 3 | 100.0 | 300.0 |
| Alagbo | Nigeria | 330 | 2 | 100.0 | 200.0 |
| Aja | Nigeria | 330 | 2 | 100.0 | 200.0 |
| Maukurdi | Nigeria | 330 | 1 | 60.0 | 60.0 |
| Ayede | Nigeria | 330 | 1 | 13.0 | 13.0 |
| Cotonou | Benin | 161 | 1 | 50.0 | 50.0 |
| Riviera | Ivory Coast | 330 | 1 | 20.0 | 20.0 |
| Atakko | Ivory Coast | 90 | 1 | 12.0 | 12.0 |
| Abengoa | Ivory Coast | 90 | 1 | 12.0 | 12.0 |
| Gagnoa | Ivory Coast | 90 | 1 | 10.0 | 10.0 |
| Lome port | Togo | 161 | 1 | 5.0 | 5.0 |
| Niamey | Niger | 132 | 1 | 2.5 | 2.5 |
| Yendi | Ghana | 161 | 1 | 2.0 | 2.0 |
| Balingue | Mali | 30 | 1 | 1.0 | 1.0 |
| Patte d'oie | Burkina Faso | 33 | 1 | 1.0 | 1.0 |
| Zagtouli | Burkina Faso | 33 | 1 | -8.0 | -8.0 |

Table 81 – Capacitors and reactors banks added to the system – 2015 peak load

The lists show many shunt capacitors. These results are due to the modeling and the
load connection at high voltage level. In the system, all loads were modeled with a
power factor of 0.85 and were often connected at HV. These shunt capacitors must
therefore be seen as a mean to compensate further the load and reduce the reactive
flow, more than a mean to keep the HV voltage in acceptable range.

For off peak load situations, other reactive compensations were needed in order to
respect the operation criteria.

Table 82 - Capacitors and reactors banks added to the system – 2015 off peak load

| Node Name | Country Name | Voltage kV | Steps # | Rating Mvar/step | Capacity Mvar |
| --- | --- | --- | --- | --- | --- |
| Birnin Kebbi | Nigeria | 330 | 3 | -33.0 | -99.0 |
| Makurdi | Nigeria | 330 | 2 | -50.0 | -100.0 |
| Kainji | Nigeria | 330 | 3 | -33.0 | -99.0 |
| Sokoto | Nigeria | 330 | 2 | -15.0 | -30.0 |
| Gombe | Nigeria | 330 | 1 | -30.0 | -30.0 |
| Jebbah | Nigeria | 330 | 1 | -33.0 | -33.0 |
| Kodeni | Burkina Faso | 225 | 1 | -20.0 | -20.0 |
| Bolgatanga | Ghana | 330 | 1 | -30.0 | -30.0 |
| Bolgatanga | Ghana | 225 | 3 | -10.0 | -30.0 |
| Boundiali | Ivory Coast | 225 | 1 | -5.0 | -5.0 |
| Ferkessedougou | Ivory Coast | 225 | 8 | -5.0 | -40.0 |
| Djougou | Benin | 161 | 2 | -5.0 | -10.0 |
| Dapaong | Togo | 161 | 1 | -5.0 | -5.0 |
| Mango | Togo | 161 | 3 | -5.0 | -15.0 |
| Nzerekore | Guinea | 225 | 2 | -5.0 | -10.0 |

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

In off peak load situation, the results show only reactor banks. At off peak load, the
high voltage lines are low loaded and generate reactive power. The reactor banks are
mandatory to absorb that reactive power generation and prevent over-voltages.

It is important to link reactors with the lines, so that in case of line tripping, the
reactive power generation of the line disappears in the same time than the reactive
power absorption of the reactor bank. Otherwise, there is a risk of low voltage
and/or voltage collapse.

3.4.2.2. 2020

Besides all the investments presented in the scenario description, additional
investments were needed to keep the voltages in the acceptable range.

The list of new capacitor banks is given in Table 834.

Mainly, the load centres of Abidjan (Ivory Coast), Dakar (Senegal), Bissau (Guinea
Bissau), Bamako (Mali) and Ouagadougou (Burkina Faso) need capacitor banks to
support their voltage while they are importing power.

| Node Name | Country Name | Voltage kV | Steps # | Rating Mvar/step | Capacity Mvar |
| --- | --- | --- | --- | --- | --- |
| Lafia | Mali | 150 | 3 | 10.0 | 30.0 |
| Balingue | Mali | 30 | 3 | 10.0 | 30.0 |
| Balingue | Mali | 15 | 3 | 10.0 | 30.0 |
| Thiona | Senegal | 90 | 1 | 20.0 | 20.0 |
| tobene | Senegal | 90 | 2 | 20.0 | 40.0 |
| Taiba | Senegal | 90 | 1 | 20.0 | 20.0 |
| Bel Air | Senegal | 90 | 2 | 15.0 | 30.0 |
| Kayes | Senegal | 225 | 1 | -30.0 | -30.0 |
| Amarya | Guinea | 225 | 1 | -25.0 | -25.0 |
| Bissau | Guinea Bissau | 30 | 2 | 10.0 | 20.0 |
| Ouagadougou 190 | Burkina Faso | 90 | 3 | 10.0 | 30.0 |
| Ouagadougou 290 | Burkina Faso | 90 | 1 | 10.0 | 10.0 |
| Zagtouli | Burkina Faso | 225 | 1 | 20.0 | 20.0 |
| Bundiali | Ivory Coast | 225 | 1 | 20.0 | 20.0 |
| Bia Sud | Ivory Coast | 90 | 7 | 10.0 | 70.0 |
| Yopougnon | Ivory Coast | 90 | 4 | 10.0 | 40.0 |
| Korhogo | Ivory Coast | 90 | 1 | 15.0 | 15.0 |
| Daloa | Ivory Coast | 90 | 1 | 15.0 | 15.0 |
| Gagnoa | Ivory Coast | 90 | 1 | 10.0 | 10.0 |
| Bouake | Ivory Coast | 90 | 4 | 10.0 | 40.0 |
| Yamoussoukro | Ivory Coast | 90 | 1 | 12.0 | 12.0 |
| Dimbokro | Ivory Coast | 90 | 1 | 12.0 | 12.0 |
| Agnibilekrou | Ivory Coast | 90 | 1 | 6.0 | 6.0 |
| Divo | Ivory Coast | 90 | 1 | 12.0 | 12.0 |
| Dabou | Ivory Coast | 90 | 1 | 12.0 | 12.0 |
| Abobo | Ivory Coast | 90 | 2 | 15.0 | 30.0 |

Table 834 - Capacitors and reactors banks added to the system – 2020 peak load

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

3.4.2.3. 2025

Besides all the investments presented in the scenario description, additional
investments were needed to keep the voltages in the acceptable range.

The list of new capacitor banks is given in Table 845.

Mainly, the load centres of Abidjan and Yamoussoukro (Ivory Coast), Dakar
(Senegal), Kumasi (Ghana), Bobo Diolasso and Ouagadougou (Burkina Faso) and
Lagos, Abuja and Kano (Nigeria) need capacitor banks to support their voltage
while they are importing power.

The north of Ivory Coast was also compensated to unload the 225/90 kV
transformers of Boundiali and Ferkessedougou.

| Node Name | Country Name | Voltage kV | Steps # | Rating Mvar/step | Capacity Mvar |
| --- | --- | --- | --- | --- | --- |
| Bobo 1 | Burkina Faso | 33 | 3 | 7 | 21 |
| Kodeni | Burkina Faso | 33 | 3 | 7 | 21 |
| Ouaga 1 | Burkina Faso | 90 | 3 | 10 | 30 |
| Patte d'oie | Burkina Faso | 33 | 3 | 5 | 15 |
| Ferkessedougou | Ivory Coast | 90 | 5 | 5 | 25 |
| Riviera | Ivory Coast | 90 | 3 | 10 | 30 |
| Bia sud | Ivory Coast | 90 | 3 | 10 | 30 |
| Yopougnon | Ivory Coast | 90 | 3 | 10 | 30 |
| Divo | Ivory Coast | 90 | 1 | 12 | 12 |
| Yamoussoukro | Ivory Coast | 90 | 1 | 12 | 12 |
| Attakro | Ivory Coast | 90 | 1 | 6 | 6 |
| Daloa | Ivory Coast | 90 | 2 | 10 | 20 |
| Agnibilekro | Ivory Coast | 90 | 1 | 6 | 6 |
| Achimota | Ghana | 34.5 | 2 | 21.6 | 43.2 |
| Kenyasi | Ghana | 161 | 4 | 10 | 40 |
| Mim | Ghana | 161 | 1 | 10 | 10 |
| Kumasi | Ghana | 161 | 1 | 25 | 25 |
| New Aberim | Ghana | 161 | 2 | 10 | 20 |
| Asawinso | Ghana | 161 | 2 | 10 | 20 |
| New Obuasi A | Ghana | 11.5 | 1 | 5.4 | 5.4 |
| New Obuasi B | Ghana | 11.5 | 1 | 5.4 | 5.4 |
| New Obuasi C | Ghana | 11.5 | 1 | 5.4 | 5.4 |
| Maiduguri | Nigeria | 330 | 2 | 50 | 100 |
| Ikeja West | Nigeria | 330 | 5 | 100 | 500 |
| Akangba | Nigeria | 330 | 2 | 100 | 200 |
| Zaria | Nigeria | 330 | 2 | 50 | 100 |
| Kano | Nigeria | 132 | 2 | 100 | 200 |
| Abuja | Nigeria | 330 | 3 | 100 | 300 |
| Ayiede | Nigeria | 330 | 2 | 100 | 200 |
| Oshogbo | Nigeria | 330 | 3 | 100 | 300 |
| Sakal | Senegal | 30 | 5 | 5 | 25 |
| Taiba | Senegal | 90 | 1 | 5 | 5 |
| Tobene | Senegal | 90 | 2 | 5 | 10 |
| Thiona | Senegal | 90 | 2 | 10 | 20 |

Table 845 - Capacitors and reactors banks added to the system – 2025 peak load

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

3.4.3. Static studies: Security analysis

Another important planning criterion is the N-1. In case of loss of branches (line or
transformer) the system must remain stable, must not present overloading of lines
over 110% and of transformers over 120% and must keep all voltages in the +/-10%
range.

The N-1 analysis is performed on basis of PSA model and contingencies on all
branches (over 90 kV) were simulated to report the incidents that do not respect the
criteria. Since the goal of this study is to analyze the interconnections, only the
following issues are reported here:

• Problems appearing in a country‟s network following the loss of an
interconnection;

• Problems appearing on interconnections following a contingency inside a
country‟s network;
Problems appearing on interconnections following the loss of an interconnection.

• Problems appearing on interconnections following the loss of an interconnection.

3.4.3.1. 2015

3.4.3.1.1. Base case peak load

Lines contingencies

Table presents the lines contingencies results for the Base case, at peak load.

| Lines Name | Voltage level kV | ResultsCriteria not respected |
| --- | --- | --- |
| Bolgatanga-Zebila | 161 | Overvoltages in 161kV-north Togo |
| Zebila-Bawku | 161 | Overvoltages in 161kV-north Togo |
| Dapaong-Bawku | 161 | Overvoltages in 161kV-north Togo |
| Guene-Kandi | 161 | Overvoltages in 161kV-north Togo |
| Guene-Malanville | 161 | Overvoltages in 161kV-north Togo |
| Sakal-Tobene | 225 | Overvoltages in 225kV-Mali and Senegal |
| Koutiala-Segou | 225 | Undervoltages at Segou 225kV and 150kV |
| Kodeni-Bolgatanga | 225 | Undervoltages in 330kV,225kV,132kV and 90kV-Ivory Coast and Burkina Faso |
| Pa-Kodeni | 225 | Undervoltage at Pa 225kV-Burkina Faso |

For the lines listed here above, the system was not able to support a simple line
tripping (without fault) and respect the operation criteria. The incidents are:

• Over-voltages in Mali and Senegal when the OMVS interconnection is tripped.
Under-voltages at Segou when part of the interconnection between Mali and

• Under-voltages at Segou when part of the interconnection between Mali and
Ivory Coast is tripped.
Under-voltages in Burkina Faso, and part of Ivory Coast, when parts of the

Table 85 – Lines contingencies for the Base case, peak load situation

• Under-voltages in Burkina Faso, and part of Ivory Coast, when parts of the
interconnections towards Burkina Faso are tripped.

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

Transformers contingencies

Table presents the transformers contingencies results for the Base case, at peak
load.

| Transformer Name | Voltage level kV | Results Criteria not respected |
| --- | --- | --- |
| Malanville | 330/161 | Overvoltages in the north of Togo and Benin |
| Kodialani | 225/150 | Parallel transformer overloaded at Kodialani |
| Bolgatanga | 225/161 | Undervoltage in Burkina Faso and Niger |

Table 86 – Transformers contingencies for the Base case, peak load situation

The incidents are:

• Over-voltages in the north of Benin when the North-core interconnection with
Niger and Nigeria is tripped.
Overload of the 225/150 kV transformer when the parallel transformer is tripped.

• Overload of the 225/150 kV transformer when the parallel transformer is tripped.
Under-voltages in Burkina Faso and Niger when the 225/161 kV transformer is

• Under-voltages in Burkina Faso and Niger when the 225/161 kV transformer is
tripped in Bolgatanga (Ghana). This transformer supplies the two
interconnections between Ghana and Burkina Faso.
Units contingencies

Units contingencies

All units contingencies are supported by the system, while complying with the
operation criteria. Only the contingency of Sendou coal unit, 125 MW, in Senegal,
provokes an instability. This contingency was simulated dynamically and presented
in section 3.2.2.3.2, in Figure and Figure .

3.4.3.1.2. Scenario 2 peak load

Lines contingencies

| Branch | Voltage level | Results |
| --- | --- | --- |
| Name | kV | Criteria not respected |
| Sikasso-Ferkessedougou | 225 | Overloaded line Zagtouli-Ouagadougou-Burkina Faso |
| Abobo-Elubo | 225 | Line Zebila-Bawku overloaded |
| Bolgatanga-Zebila | 161 | Overvoltage in the north of Togo-161kV |
| Zebila-Bawku | 161 | Overvoltage in the north of Togo-161kV |
| Dapaong-Bawku | 161 | Overvoltage in the north of Togo-161kV |
| Onigbolo-Sakete | 161 | Overvoltage in the north of Benin-161kV |
| Mango-Dapaong | 161 | Overvoltage in the north of Benin-161kV |
| Kodialani-Kalaban Coro | 150 | Overloaded transformers in Segou-Mali |
| Koutiala-Segou | 225 | Undervoltage in Segou-Mali |
| Parakou-Onigbolo | 161 | Undervoltage in the north of Benin-161kV |

Table 87 – Lines contingencies for the Scenario 2, peak load situation

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

The results from the Base case are also valid for Scenario 2 except for:

• The contingencies on interconnection lines that are not in service in Scenario 2.
The contingencies on the axes towards Burkina Faso (Kodeni – Bolgatanga and

• The contingencies on the axes towards Burkina Faso (Kodeni – Bolgatanga and
Pa – Kodeni). In scenario 2, Burkina Faso imports less power because fewer
interconnections are available. There are more units in service inside the country
and it is consequently easier to keep the voltages in the required range.
The contingency on the line Sakal – Tobene. In the Base case, it provokes a flow

• The contingency on the line Sakal – Tobene. In the Base case, it provokes a flow
redirection from Mali to Senegal via the OMVG interconnection. It does not
fulfill the operation criteria in this static analysis and it will be shown in the
dynamic simulations that the system loses stability. In scenario 2, this
contingency provokes the split of Senegal from the main system. It will be
observed dynamically whether Senegal can face such incident.
Other incidents are also detected:

Other incidents are also detected:

• The contingency on the Ivory Coast-Mali interconnection provokes the overload
of a 90 kV line inside Burkina Faso.
The contingency on the 225 kV interconnection between Ghana and Ivory Coast

• The contingency on the 225 kV interconnection between Ghana and Ivory Coast
provokes an overload on 161 kV line Bawku-Zebila in north Ghana.
Contingencies in the 161 kV network of Togo and Benin provoke over and

• Contingencies in the 161 kV network of Togo and Benin provoke over and
under-voltages in the north of Benin.
The contingency on the 150 kV line between Kodialani and Kalaban Coro in

• The contingency on the 150 kV line between Kodialani and Kalaban Coro in
Mali provokes the overload of the transformers at Segou.
Transformers contingencies

Transformers contingencies

For Scenario 2, there is no transformer contingency provoking a network state that
does not fulfil the criteria. In comparison with the Base case:

• The North-core interconnection is not yet commissioned. There is consequently
no transformer in Malanville.
The interconnection Ghana-Burkina Faso-Mali is not yet commissioned. There

• The interconnection Ghana-Burkina Faso-Mali is not yet commissioned. There
are fewer exchanges towards Mali and the transformer contingency in Kodialani
respects the operation criteria.
Burkina Faso is less interconnected and imports less energy. There are

• Burkina Faso is less interconnected and imports less energy. There are
consequently more units and it is easier to maintain the voltages in the required
range.
Units contingencies

Units contingencies

For some machine contingencies, the system is not able to support the transient and
recover to a steady-state satisfying the operation criteria. Table lists all machines
contingencies leading to the non-respect of the operation criteria.

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

| Unit | Results |
| --- | --- |
| Name | Criteria not respected |
| BLACKHG1/2/3 | Under-voltage at Freetown-Sierra Leone |
| NIGERSOL | Voltage collapse in Niger |
| MANEAH | Voltage collapse in Guinea/Sierra Leone/Liberia |
| CAPDB19A | Low voltages in Senegal |
| KOUDI\_1G/2G | Low voltages in Senegal |
| KAHONG71/2/3/4 | Voltage collapse in Senegal |
| SENDOU1G | Low voltages in Senegal and loss of synchronism |
| CAPDB11A | Low voltages in Senegal and loss of synchronism |
| TOBIN\_1G | Low voltages in Senegal and loss of synchronism |
| GTI\_111A | Low voltages in Senegal and loss of synchronism |
| ALBATR1G | Loss of synchronism in Mali |
| 4KOS6\_11 | Overload line Zagtouli-Ouagadougou 90kV-Burkina Faso |

Table 88 – Machines contingencies for Scenario 2, peak load situation

Many machines are in Senegal. Their contingency provokes an additional import to
replace the power lost and the transit increase reaches states beyond the stability
limits, provoking the loss of synchronism of other units in Senegal.

Other incidents are important in Freetown (Sierra Leone), Conakry (Guinea) and
Niamey (Niger, River area) where the loss of one unit can cause low voltages or
even voltage collapse.

The loss of ALBATR1G in Mali causes loss of synchronism of other units in Mali.

Finally, the loss of one unit in Burkina Faso provokes the overload of a 90 kV line
close to Ouagadougou.

3.4.3.1.3. Base case off peak load

Table 896 presents the lines contingencies for the Base case, at off peak load
condition.

| Lines | Voltage level | Results |
| --- | --- | --- |
| Name | kV | Criteria not respected |
| Buchanan-Monronvia | 225 | overvoltage at Buchanan 225 kV in Liberia |
| Guene-Malanville | 161 | overvoltage in 161 kV in North Benin |
| Kaleta-Linsan | 225 | voltage collapse in Sierra Leone |
| Kodialani-Kalaban coro | 150 | over and under voltages in 150 and 225 kV in Mali |
| Koutiala-Segou | 225 | undervoltage at Segou 225 kV - Mali |
| Mbour-Sococim | 90 | undervoltage at Mbour 90 kV - Senegal |
| Monrovia-Mano | 225 | overvoltage at Mano 225 kV - Liberia |
| Papalanto-Aiyede | 330 | undervoltage at Aiyede 330 kV in Nigeria |
| Sakete-Ikeja West | 330 | overvoltage in Benin around Sakete |

Table 896 - Lines contingencies for the Base case, off peak load situation

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

The incidents are:

• The contingency on the line between Monrovia and Buchanan provokes
overvoltage in Buchanan since the SVC in Monrovia cannot influence the
voltage anymore. The same phenomenon appears for the line between Monrovia
and Mano, with overvoltage at Mano.
The 161 kV line between Guene and Malanville carries the power flow from

• The 161 kV line between Guene and Malanville carries the power flow from
Benin to Niger. If this line is tripped, the 161 kV lines in Benin towards Niger are
overloaded. They generate reactive power and there is an overvoltage.
The contingency on the line between Linsan and Kaleta provokes a redispatch of

• The contingency on the line between Linsan and Kaleta provokes a redispatch of
the flows from Kaleta to the CLSG interconnection. This new dispatching of the
flows leads to the voltage collapse of Sierra Leone.
The line between Kodialani and Kalaban Coro is important for voltage

• The line between Kodialani and Kalaban Coro is important for voltage
management in Mali.
The contingency of the line between Koutiala and Segou, in Mali, provokes

• The contingency of the line between Koutiala and Segou, in Mali, provokes
under-voltage in Segou, which becomes fed via the 150 kV lines in Mali.
Ayiede in Nigeria experiences under-voltage when its connection with the

• Ayiede in Nigeria experiences under-voltage when its connection with the
Papalanto power station is lost. The only connection remaining comes from
Oshogbo.
The loss of the interconnection between Benin and Nigeria provokes over-

Transformers contingencies

Contingencies on the transformers at Linsan and Malanville do not comply with the
operation criteria. The contingency on the transformer at Linsan provokes the
overloading of the parallel transformer. At Malanville, as for peak load situation, the
contingency provokes overvoltages in the north of Togo and Benin.

| Transformer Name | Voltage level kV | Results Criteria not respected |
| --- | --- | --- |
| Linsan | 225/110 | overload parallel transformer |
| Malanville | 330/161 | overvoltages in 161kV in north Benin |

Table 907 - Transformers contingencies for the Base case, off peak load situation

Units contingencies

The loss of the SVC at Monrovia provokes high voltages along the CLSG
interconnection. The highest voltage is located at Buchanan 225 kV bus bar, with
1.14 pu.

Two unit contingencies do not fulfil the operation criteria. They are presented in
Table 918.

| Unit | Results |
| --- | --- |
| Name | Criteria not respected |
| SVCMONRO | Overvoltages in Liberia 225kV |
| WIND\_1G | Voltage collapse in Senegal |

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

The contingency on the wind farm in Senegal leads to voltage collapse in Senegal.
In this scenario, the wind farm produces 60 MW. The reason of the collapse is
related to the maximum transfer capacity limit of the lines towards Senegal. This
case will be illustrated in the section simulating dynamically the units‟
contingencies.

3.4.3.1.4. Scenario 2 off peak load

Lines contingencies

Table 929 lists the contingencies that do not comply with the operation criteria.

| Branch | Voltage level | Results |
| --- | --- | --- |
| Name | kV | Criteria not respected |
| Bolgatanga - Ouagadougou | 225 | voltage collapse in Burkina Faso |
| Papalanto - Aiyede | 330 | undervoltage at Aiyede 330 kV in Nigeria |
| Zebila-Bawku | 161 | overvoltage in North Benin 161 kV |
| Buchanan-Monrovia | 225 | overvoltage in 225 kV at Liberia, Guinea (Nzerekore) and Man |
| Ferkessedougou-Kodeni | 225 | voltage collapse in Bobo area in Burkina Faso |
| Kara-Djougou | 161 | overvoltages in 161 kV in North Togo and Benin |
| Abobo-Elubo | 161 | undervoltages in 161 kV in north Ghana |
| Bolgatanga-Zebila | 161 | overvoltage in North Benin 161 kV |
| Sakete-Ikeja West | 330 | overvoltages in 161 and 330 kV in Benin |
| Zagtouli-Ouagadougou | 90 | voltage collapse in Ouagadougou in Burkina Faso |
| Sakete-Onigbolo | 161 | overvoltage in North Benin 161 kV |
| Ouagadougou-Ouagadougou | 90 | voltage collapse in Ouagadougou in Burkina Faso |

Table 929 - Lines contingencies for Scenario 2, off peak load situation

The incidents are the same than for the Base case, except for:

• The contingencies on interconnection lines that are not in service in Scenario 2.

• Incidents that now lead to the splitting of the system in two parts. For instance, in
the Base case, the loss of the 150 kV line between Kodialani and Kalaban Coro
in Mali provokes voltage problems. In Scenario 2, it provokes the splitting of the
system in two parts: Senegal and one part of Mali, and the rest with the other part
of Mali. The interconnection passes from 225 kV to 150 kV in Mali and back to
225 kV in Mali.
Besides, the incidents show:

• The loss of the interconnection between Ghana and Burkina leads to voltage
collapse in Burkina Faso. This will be illustrated in the dynamic simulations
• The regions of north Togo and north Benin still have very sensitive voltages.

• The loss of the interconnection between Ivory Coast and Ghana forces the energy
that comes from Ghana and goes to Ivory Coast to pass through Burkina Faso.
This additional flow provokes low voltages in 161 kV in north of Ghana.
90 kV lines inside Ouagadougou area in Burkina Faso should be reinforced to

• 90 kV lines inside Ouagadougou area in Burkina Faso should be reinforced to
allow this area importing power.

The regions of north Togo and north Benin still have very sensitive voltages.
The loss of the interconnection between Ivory Coast and Burkina Faso provokes

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

Transformers contingencies

For Scenario 2, at off peak load situation, there is no transformer contingency
provoking a network state that does not fulfill the criteria.

Units contingencies

| Unit Name | ResultsCriteria not respected |
| --- | --- |
| 2NEWCC-1/2 | Overload on line Bawku-Zebila in Ghana |
| MANAN14/5A | Overload on line Bawku-Zebila in Ghana and tfo at Segou in Mali |
| 20NTAG82/3 | Overload on line Bawku-Zebila in Ghana |
| MANEAHG1/2 | Overload on line Bawku-Zebila in Ghana |
| SVCMONRO | Overvoltages in Liberia 225kV |
| 4OUA24/5\_5 | Overload line Zagtouli-Ouagadougou 90kV-Burkina Faso |
| 2027VRID | Overload on line Bawku-Zebila in Ghana |
| GTI\_111A | Low voltages in Senegal,Mali and Ivory Coast+ Overloads of tfo at Segou and 150kV line in Mali |
| BUI\_G1 | Overload on line Bawku-Zebila in Ghana |

Table 10 - Machines contingencies for Scenario 2, off peak load situation

The loss of the SVC at Monrovia provokes high voltages on the CLSG
interconnection.

In case of big unit contingency (Manantali, GTI in Senegal, …), there is a risk of
overloading the transformers at Segou and the 150 kV lines in Mali, with low
voltages in Ivory coast, Mali and Senegal. This is due to the flows redispatch with
the unblocking of the primary reserve.

The 90 kV line between Ouagadougou and Zagtouli is overloaded for unit
contingencies in Ouagadougou.

The 161 kV line between the north of Ghana and Togo, in case a machine greater
than 40 MW is lost in Mali, Senegal, Guinea or Ivory Coast. This line between

than 40 MW is lost in Mali, Senegal, Guinea or Ivory Coast. This line between
Bawku and Zebila has a low rating capacity of 43 MVA in comparison of other
elements of the interconnection between the north of Ghana and Togo. The lines
between Bawku and Dapaong are rated 120 MVA, while the line between Dapaong
and Mango is rated 120 MVA.

than 40 MW is lost in Mali, Senegal, Guinea or Ivory Coast. This line between
Bawku and Zebila has a low rating capacity of 43 MVA in comparison of other
elements of the interconnection between the north of Ghana and Togo. The lines
between Bawku and Dapaong are rated 120 MVA, while the line between Dapaong
and Mango is rated 120 MVA.

3.4.3.2. 2020

• Problems of power evacuation. The lines to evacuate the power from Adjaralla,
Koukoutamba and Boureya are insufficient.
Over-voltages in north of Benin and Togo, as already detected for 2015 remains.

The problems for lines contingencies are the following:

• Over-voltages in north of Benin and Togo, as already detected for 2015 remains.

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

• Large importations from some countries whose network‟s stability is very
difficult to keep. It is the case for Senegal, Burkina Faso and Mali. A good
coordination between the lines and the reactances should allow avoiding some
problems but it is not enough to support the N-1. Voltage support is deficient and
the import level is difficult to support. The possible solutions are the installation

Large importations from some countries whose network‟s stability is very
difficult to keep. It is the case for Senegal, Burkina Faso and Mali. A good
coordination between the lines and the reactances should allow avoiding some
problems but it is not enough to support the N-1. Voltage support is deficient and
the import level is difficult to support. The possible solutions are the installation

the import level is difficult to support. The possible solutions are the installation
of SVC, the operation of more units inside the country to provide voltage support
and reduce the imports or the reinforcement of the interconnections.

• Large loops composed of long interconnection whose stability is very difficult to
keep. Some elements contingencies on the loop provoke flows redistributions
that are not supported by the network. In case of reinforcements, the whole loop
does not need to be doubled. Doubling only part of it is sufficient.
-The loop Linsan-Manantali-Bamako-Fomi

-The loop Linsan-Manantali-Bamako-Fomi
-The OMVG loop

-The OMVG loop
-The loop between Fomi-Kodialani-Sikasso-Ferkessedougou-Boundiali

-The loop between Fomi-Kodialani-Sikasso-Ferkessedougou-Boundiali
-The loop between Matam-Kayes-Tobene-Kaolack-Tambacounda

-The loop between Matam-Kayes-Tobene-Kaolack-Tambacounda

| Lines | Voltage level | Results |
| --- | --- | --- |
| Name | kV | Criteria not respected |
| Linsan-Dabola | 225 | overloads on 225 kV lines Boureya-Manantali-Tkita |
| Dabola-Koroussi | 225 |  |
| Koroussi-Fomi | 225 |  |
| Linsan-Kamakwie | 225 | overloads on 225 kV lines Boureya-Manantali |
| Kamakwie-Yiben | 225 |  |
| Yiben-Bumbuna | 225 |  |
| Sambangalou-Tambacounda | 225 |  |
| Tambacounda-Kaolack | 225 | instability |
| Kaolack-Touba | 225 |  |
| Kaleta-Boke | 225 |  |
| Boke-Saltinho | 225 |  |
| Saltinho-Bambadinca | 225 |  |
| Bambadinca-Mansoa | 225 |  |
| Mansoa-Tanaf | 225 | instability |
| Tanaf-Soma | 225 |  |
| Linsan-Koukoutamba | 225 |  |
| Boureya-Manantali | 225 |  |
| Kayes-Matam | 225 |  |
| Matam-Dagana | 225 |  |
| Fomi-Bundialani | 225 |  |
| Ouelessedougou-Kodialani | 225 | instability |
| Ouelessedougou-Sikasso | 225 |  |
| Bundialani-Ferkessedougou | 225 |  |
| Fomi-Siguir | 225 | overload on 225 kV line Ouelessedougou-Kodialani |
| Man-Yekepa | 225 | overload on 225 kV line Boureya-Manantali |
| Bolgatanga-Ouagadougou | 225 | instability |
| Ouagadougou est-Zagtouli | 225 | overload 90 kV line Zagtouli-Ouagadougou |
| Adjaralla-Ava | 161 | overload 161 kV lines Adjaralla-Nangbeto-Mome Hagou |
| Guene-Malanville | 161 | over-voltages in north Benin |
| Zabori-Malanville | 330 | over-voltages in north Benin |
| Zebila-Bawku | 161 | over-voltage in north Togo |

Table 9411 - Lines contingencies for 2020 peak load situation

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

The problems for transformers contingencies are related to the problems detected for
lines, except for the north of Ivory Coast that is insufficiently fed with the three
transformers at Ferkessedougou, Boundiali and Laboa.

| Transformer Name | Voltage level kV | Results Criteria not respected |
| --- | --- | --- |
| Selingue | 225/150 | overloads on 225/150kV tfo at Kodialani and overloads on lines Kodialani Kalaba Coro in Mali |
| Malanville | 330/161 | over-voltages in north Benin |
| Ferkessedougou | 225/90 | instability in north Ivory Coast |
| Laboa | 225/90 | instability in north Ivory Coast |
| Bundialani | 225/90 | overloads of tfos at Ferkessedougou and Laboa |

Table 95 - Transformers contingencies for 2020 peak load situation

Finally, for units contingencies, the problem detected for Senegal in 2015 remains.
The contingency of one unit in Sendou provokes the loss of 125 MW. This loss is
replaced by the unblocking of the primary reserve in Senegal but also in the other
countries. Consequently, an additional flow appears on the lines towards Senegal
provoking instability. In this scenario, the lines between Kayes and Matam and
between Sambangalou and Kaolack are highly loaded. It is interesting to note that a
contingency of 100 MW is supported by the system.

| UnitName | PowerMW | ResultsCriteria not respected |
| --- | --- | --- |
| Sendou | 125 | collapse in Senegal |

Table 96 - Units contingencies for 2020 peak load situation

3.4.3.3. 2025

The N-1 criterion is not respected in the system as it was studied for the peak load
2025 situation. The lines, transformers and units contingencies that do not comply
with the operation criteria were reported in Table , Table , Table 9912 and Table .

• in 225 kV in north Ivory Coast, for exporting the hydro power coming from the
CLSG interconnection and from the Soubre area to Burkina Faso.
in 225 kV between Boureya, Manantali, Kodialani and Kodeni (Guinea, Mali,

• 150 kV in Bamako (Mali),

• in 161 kV in Cotonou (Benin), Lome (Togo) and Tema (Ghana),

Regional problems are also appearing with the overloads:

• in 330 kV in Lagos and Benin City (Nigeria).
Regional problems are also appearing with the overloads:

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

| Lines Name | Voltage level kV | Results Criteria not respected |
| --- | --- | --- |
| Sococim-Thiona | 90 | parallel line overloaded |
| Zagtouli-Ouagadougou | 90 | parallel line overloaded |
| Maria Gleta-Cotonou | 161 | parallel line overloaded |
| Manantali-Tkita | 225 | parallel line overloaded |
| Ajaoku-Geregu | 330 | parallel line overloaded |
| Erunkan-Ikeja West | 330 | parallel line overloaded |
| Boureya-Manantali | 225 | parallel line overloaded |
| Volta-Tema | 161 | parallel line overloaded |
| Niamey-Birnin Kebbi | 132 | parallel line overloaded |
| Lome-Lome Port | 161 | parallel line overloaded |
| Sirako-Balingue | 150 | parallel line overloaded |
| Ouelessedougou-Kodialani | 225 | parallel line overloaded |
| Ouaga Est-Kossodo | 90 | parallel line overloaded |
| Treichville-Vridi | 90 | parallel line overloaded |
| Ouaga 1-PC | 90 | parallel line overloaded |
| PC-Kossodo | 90 | parallel line overloaded |
| Kounoune-Tobene | 225 | overload 90kV line Mbour-Sococim |
| Bouake-Kossou | 90 | overload 90kV line Bouake 1-Bouake 2 |
| Ayiede-Oshogbo | 330 | overload 330kV line Ayiede-Papalanto |
| Cap des biches-Sococim | 90 | overload 90kV line Kounoune-Sococim |
| Ferkessedougou-Kodeni | 225 | overload 225kV line Sikasso-Kodeni |
| Kounoune-sococim | 90 | overload 90kV line Cap des biches-Sococim |
| Bundialani-Ferkessedougou | 225 | overload tfo 225/90 Bundialani |
| Ouaga Est-Zagtouli | 225 | overload 90kV lines Zagtouli-Ouaga 2 and Ouaga 2-Ouaga 1 and tfos 225/90 Zagtouli |

Table 97 – Lines contingencies provoking overload problems (peak load 2025 situation)

Secondly, Table lists all the lines contingencies leading to voltage problems and
collapses. The following areas are concerned:

• 90 kV network around Kossou, Taabo and Boake in Ivory Coast.
161 kV in Freetown. The stability relies on the two lines from Bumbuna, which

• 161 kV in Freetown. The stability relies on the two lines from Bumbuna, which
are insufficient.
161 kV in Kpan in Ghana

• Areas of Katsina and Maiduguri in north of Nigeria, that should be more
compensated.
Area of Ayiede in Nigeria, which is only connected via two lines and

• Area of Ayiede in Nigeria, which is only connected via two lines and
insufficiently compensated.
• Areas of Dagana and Sakal in Senegal, where the loss of the OMVS

• Niamey, Salkadamna and north of Benin, experiencing overvoltages when the
North-core interconnection is lost between Niger-Benin-Nigeria.
Also, the transmission of hydro power from West to East is a problem. The loss of

• Areas of Dagana and Sakal in Senegal, where the loss of the OMVS
interconnection from Kayes provokes a flow redistribution that is not supported.
• The Gambia and Guinea Bissau, fed from Kaleta, do not support a contingency

• The Gambia and Guinea Bissau, fed from Kaleta, do not support a contingency
on the 225 kV lines between Kaleta and Mansoa. The flow redistribution
provokes voltage collapses.
The substation of Buchanan 225 kV, experiencing over-voltages when the link

Also, the transmission of hydro power from West to East is a problem. The loss of
one of these interconnections reduces the transfer capacity and leads to instability:

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

• CLSG interconnection between Man and Yekepa:
-Fomi-Boundiali

-Fomi-Boundiali
-Kodialani-Kodeni

-Kodialani-Kodeni
-Kodeni-Bolgatanga

-Kodeni-Bolgatanga
-Riviera-Prestea

-Riviera-Prestea

| Lines Name | Voltage level kV | Results Criteria not respected |
| --- | --- | --- |
| Buchanan-Monrovia | 225 | overvoltages at Buchanan |
| Agbo-Yopo | 90 | undervoltage at Agbo |
| Dagana-Sakal | 225 | overvoltages at Dagana and Matam |
| Kano-Katsina | 330 | undervoltage at Katsina |
| Birnin Kebbi-Malanville-Niamey | 330 | overvoltages in Niamey, Salkadamna and north Benin |
| Prestea-Riviera | 330 | instability |
| Gombe-Damaturi | 330 | voltage collapse in Maiduguri, Nigeria |
| Papalanto-Ayiede | 330 | voltage collapse in Ayiede |
| Kaolack-Touba | 225 | voltage collapse in Touba, Senegal |
| Bambadinka-Mansoa | 225 | instability |
| Bambadinka-Saltinho | 225 |  |
| Boke-Saltinho | 225 |  |
| Fomi-Bundialani | 225 | instability |
| Sikasso-Kodeni | 225 | instability |
| Sikasso-Ouelessedougou | 225 | instability |
| Man-Yekepa | 225 | instability |
| Soubre-San Pedro | 225 | instability |
| Tiboto-San Pedro | 225 |  |
| Bouake 2-Kossou | 225 | collapse at Bouake |
| Kodeni-Bolgatanga | 225 | instability |
| Bumbuna-Freetown | 161 | voltage collapse in Freetown in Sierra Leone |
| Asie-Kpan | 161 | voltage collapse in Kpan in Ghana |
| Bouake 1-Bouake 2 | 90 | voltage collapse in Bouake 1 |
| Bouake-Agnibilekro | 90 | voltage collapse in area of Dimbokro-Attakro-Abengourou-Agnibilekro |
| Kossou-Yamoussoukro | 90 |  |
| Taabo-Dimbokro | 90 |  |
| Dimbokro-Attakro | 90 |  |
| Attakro-Abengourou | 90 |  |
| Gagnoa-Kossou | 90 | voltage collapse in Gagnoa, Ivory Coast |
| Hire-Taabo | 90 | voltage collapse at Divo, Ivory Coast |
| Hire-Divo | 90 |  |

Table 98 – Lines contingencies provoking voltage problems and instability (peak load 2025 situation)

The transformers contingencies, listed in Table 9912, confirm the problems already
mentioned and show substations where transformers should be reinforced.

Finally, Table presents the units contingencies that are not supported by the system.
These contingencies concern large units located in the eastern part of the WAPP
system. Their contingencies provoke the unblocking of the primary reserve, mainly
in Nigeria, leading to flow redistribution where the flows from East to West are
reduced. This reduction provokes over-voltages in the north of Ivory Coast and leads
to instability

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

| Transformer Name | Voltage level kV | Results Criteria not respected |
| --- | --- | --- |
| Bumbuna | 225/161 | parallel tfo overloaded |
| Tobene | 225/90 | parallel tfo overloaded |
| Kumasi | 330/161 | parallel tfo overloaded |
| Riviera | 330/225 | parallel tfo overloaded |
| Segou | 225/150 | parallel tfo overloaded |
| Bouake | 225/90 | parallel tfo overloaded |
| Matam | 225/90 | parallel tfo overloaded |
| Kodeni | 225/33 | parallel tfo overloaded |
| Kano | 330/132 | voltage collapse in north of Nigeria |
| Katsina | 330/132 | voltage collapse in north of Nigeria |

Table 9912 - Transformers contingencies for 2025 peak load situation

3.4.4. Static studies: Short-circuit analysis

Short-circuit analysis were performed at peak load, for years 2015, 2020 and 2025.

3.4.4.1. 2015

Short-circuit analysis results are presented in appendix in Table , Table , Table and
Table .

They were calculated for the Base case and for Scenario 2, first with the
configuration of the scenario (the machines out of service are disconnected), second
with all machines connected to reach the maximum short circuit level.

• Abobo 90 kV, Vridi 90 kV, Plateau 90 kV, Bia nord 90 kV and Treichville 90 kV
in Ivory Coast.
The area of Abidjan will see the installation of new units in Riviera and Vridi

The area of Abidjan will see the installation of new units in Riviera and Vridi
which are responsible for the high currents calculated. Some documents collected
mentioned that breaker capacities will be or would be already upgraded for some
of these substations. The calculations expect levels above 25 kA and even above
31.5 kA sometimes. The upgrade should consequently be important enough to
cover these levels.

The area of Abidjan will see the installation of new units in Riviera and Vridi
which are responsible for the high currents calculated. Some documents collected
mentioned that breaker capacities will be or would be already upgraded for some
of these substations. The calculations expect levels above 25 kA and even above
31.5 kA sometimes. The upgrade should consequently be important enough to

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

• Volta 161 kV and Smelter 161 kV in Ghana.
The area between Akosombo and Tema was already facing high levels of short-

The area between Akosombo and Tema was already facing high levels of shortcircuit currents. In 2015, the apparition of new units in Tema and Asogli will
increase even more these levels. Calculations also showed levels above 90% for
Akosombo 161 kV, Tema TT1P 161 kV and Asogli 161 kV, though they are still
acceptable.
Afam 330 kV, Alaoji 330 kV, Benin City 330 kV, Benin North 330 kV, Egbin

• Afam 330 kV, Alaoji 330 kV, Benin City 330 kV, Benin North 330 kV, Egbin
330 kV, Erunkan 330 kV, Eyaen 330 kV, Ikeja West 330 kV, Ikot Ekpene 330
kV, Onitsha 330 kV and Owerri 330 kV in Nigeria.
The south of Nigeria, with the region of Lagos, Benin City and Port Harcourt is

The south of Nigeria, with the region of Lagos, Benin City and Port Harcourt is
already very dense and loaded. In 2015, several new power plants will be
commissioned in these areas. The reinforcements in the 330 kV network and the
installation of the 760 kV super grid will also contribute to increase the shortcircuit levels. For the here-above quoted substations, the short-circuit current
levels are above the breaker capacity. For Aja 330 kV, Ikot Abasi 330 kV and
Sapele 330 kV nodes the short-circuit currents calculated are high (above 90% of
rated breaker capacity) but still acceptable. Some documents collected mention
breaker capacities above 31.5 kA (at 40 and 50 kA) but without detailing for
which substations. It is important to make sure these substations are concerned.
Cap des Biches 90 kV in Senegal.

• Cap des Biches 90 kV in Senegal.
The maximum current calculated is acceptable. Attention is drawn here because

The maximum current calculated is acceptable. Attention is drawn here because
it is between 90 and 100% of breaker capacity. This high level is due to the
installation of new capacities at Cap des Biches.
The modeling assumptions must be kept in mind for analyzing the short-circuits

The modeling assumptions must be kept in mind for analyzing the short-circuits
levels calculated. For many countries, no information was collected about the
internal reinforcements. Important parameters like step up transformers impedance
were assumed.

3.4.4.2. 2020 AND 2025

The short-circuit calculations showed the same problems than for 2015. The
development of large hydro power plants in the eastern part of the WAPP system is
not problematic, for what concerns short-circuits levels, if the impedances of the
step-up transformers is correctly designed, and assuming their connections in 225
kV with a breaking capacity of 31.5 kA.

As a conclusion, the three phases short-circuit current levels could be reduced by
taking the following actions:

3.4.4.3. CONCLUSIONS

• Designing the impedance of the step up transformers to limit such currents;
Inserting serial reactances at critical substations;

• Avoiding locating all the units at the same site, or close from areas having
already high short circuits levels.
The locations where values exceeding the breaking capacities were detected should

The locations where values exceeding the breaking capacities were detected should
be checked to verify that the assumptions done for the breaking capacities are
underestimated.

The results are given in Table , Table and Table in appendix.

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

3.4.5. Dynamic studies: Small signal stability

The small signal stability of the system was checked by calculation of the
eigenvalues using HERCULES, according to the methodology described above.

3.4.5.1. 2015 PEAK LOAD: BASE CASE

For the Base case, the following modes have a damping coefficient lower than 5.0%.

| Mode | Real | Imaginary | ζ(%) | Freq(Hz) |
| --- | --- | --- | --- | --- |
| 1 | -0.016 | 3.146 | 0.51% | 0.501 |
| 2 | -0.194 | 5.980 | 3.24% | 0.952 |
| 3 | -0.076 | 2.207 | 3.43% | 0.351 |
| 4 | -0.238 | 5.403 | 4.41% | 0.860 |

Table 101 - Characteristics of the least damped modes – Base case (peak load)

These modes are related to inter-area oscillations and the first three will be studied
here:

• Mode 1 is an inter-area oscillation between Ghana/Ivory Coast and
Senegal/Guinea.
Mode 2 is an inter-area oscillation between Mali and Senegal.

• Mode 2 is an inter-area oscillation between Mali and Senegal.
Mode 3 is an inter-area oscillation between Senegal/Guinea and Nigeria.

• Mode 3 is an inter-area oscillation between Senegal/Guinea and Nigeria.
The tables and charts below illustrate the modes.

The tables and charts below illustrate the modes.

The mode shape graph in Figure illustrates the resonance between the two groups of
machines for mode 1. It is an oscillation between Ghana/Ivory Coast and
Senegal/Guinea. With the information in Table 13, one can understand the graph.
The arrows on the left side represent the machines in Ghana and Ivory Coast. The
module of the arrow gives the contribution of the machine to the oscillation and its
angle gives the phase of the contribution in the oscillation. The arrows on the right
side of the graph represent the machines in Senegal and Guinea. The phase
opposition is visible.

The same graphs and tables are provided for modes 2 and 3.

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

Figure 44 - Mode shape graph of mode 1 – Base case (peak load)

| Machines in Phase Opposition |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- |
| Country | Machine | Angle | Contribution | Country | Machine | Angle | Contribution |
| GH | DOMIT1G2 | -202.36 | 0.31 | SE | SENDOU1G | -5.46 | 0.45 |
| GH | DOMIT1G1 | -202.36 | 0.31 | SE | BELAIR1G | -2.76 | 0.40 |
| GH | ABOAT1G1 | -202.25 | 0.30 | SE | BELAIR2G | -2.76 | 0.40 |
| GH | ABOAT1G2 | -202.25 | 0.30 | SE | CAPDB19A | -2.09 | 0.40 |
| GH | ABOAT2G1 | -202.25 | 0.30 | SE | B\_AIRG62 | -3.54 | 0.40 |
| GH | ABOAT2ST | -204.52 | 0.30 | SE | B\_AIRG61 | -3.54 | 0.40 |
| GH | ABOAT1ST | -201.08 | 0.29 | SE | GTI\_113A | -2.03 | 0.40 |
| CI | 20NGTAG8 | -200.51 | 0.26 | SE | CAPDB145 | -3.71 | 0.39 |
| CI | 20NTAG82 | -200.51 | 0.26 | SE | CAPDB144 | -3.71 | 0.39 |
| CI | 2NEWCC-1 | -200.23 | 0.26 | SE | KOUN\_1G1 | -2.64 | 0.39 |
| CI | 2NEWCC-2 | -200.23 | 0.26 | SE | KOUN\_1G6 | -2.64 | 0.39 |
| CI | 2027VRIID | -200.41 | 0.26 | SE | KOUN\_1G3 | -2.64 | 0.39 |
| CI | 2028VRID | -200.39 | 0.26 | SE | KOUN\_1G4 | -2.64 | 0.39 |
| CI | 2029VRID | -200.53 | 0.26 | SE | KOUN\_1G7 | -2.64 | 0.39 |
| CI | 20NTAG83 | -200.54 | 0.26 | SE | KOUN\_1G2 | -2.64 | 0.39 |
| GH | ABOA3CC1 | -202.47 | 0.26 | SE | KOUN\_1G5 | -2.64 | 0.39 |
| CI | 2034TAAB | -196.79 | 0.26 | SE | CAPDB11A | -3.35 | 0.39 |
| CI | 2033TAAB | -196.79 | 0.26 | SE | GTI\_111A | -1.08 | 0.38 |
| CI | 2032TAAB | -196.80 | 0.26 | GU | TOMBO5G1 | 12.68 | 0.36 |
| GH | BUI\_\_\_G1 | -195.35 | 0.26 | GU | TOMBO5G3 | 12.68 | 0.36 |
| GH | BUI\_\_\_G2 | -195.35 | 0.26 | GU | TOMBO5G2 | 12.68 | 0.36 |
| GH | AKOSOMG1 | -195.49 | 0.25 | GU | GRCHUTG3 | 13.82 | 0.35 |
| GH | AKOSOMG2 | -195.49 | 0.25 | GU | GRCHUTG4 | 13.84 | 0.35 |
| GH | AKOSOMG3 | -195.49 | 0.25 | GU | GRCHUTG1 | 13.86 | 0.35 |
| GH | AKOSOMG4 | -195.49 | 0.25 | GU | GRCHUTG2 | 13.86 | 0.35 |

Table 13 – Machines in phase opposition – Mode 1 – Base case (peak load)

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

Figure 45 - Mode shape graph of mode 2 – Base case (peak load)

| Machines in Phase Opposition |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- |
| Country | Machine | Angle | Contribution | Country | Machine | Angle | Contribution |
| MA | FELOU\_3G | -248.36 | 0.66 | SE | SENDOU1G | -60.08 | 0.35 |
| MA | FELOU\_1G | -248.36 | 0.66 | SE | CAPDB19A | -49.81 | 0.22 |
| MA | FELOU\_2G | -248.36 | 0.66 | SE | GTI\_113A | -48.77 | 0.22 |
| MA | MANAN11A | -254.38 | 0.62 | SE | BELAIR1G | -50.20 | 0.22 |
| MA | MANAN12A | -254.38 | 0.62 | SE | BELAIR2G | -50.20 | 0.22 |
| MA | MANAN14A | -254.38 | 0.62 | SE | GTI\_111A | -46.80 | 0.21 |
| MA | MANAN15A | -254.38 | 0.62 | SE | B\_AIRG61 | -51.44 | 0.21 |
| MA | MANAN13A | -254.38 | 0.62 | SE | B\_AIRG62 | -51.44 | 0.21 |
| MA | KENIE\_2G | -254.26 | 0.59 | SE | CAPDB144 | -52.45 | 0.21 |
| MA | KENIE\_1G | -254.26 | 0.59 | SE | CAPDB145 | -52.45 | 0.21 |
| MA | KENIE\_3G | -254.26 | 0.59 | SE | KOUN\_1G2 | -49.78 | 0.20 |
| MA | SELING1 | -256.89 | 0.57 | SE | KOUN\_1G7 | -49.78 | 0.20 |
| MA | SELING2 | -256.89 | 0.57 | SE | KOUN\_1G4 | -49.78 | 0.20 |
| MA | SELING3 | -256.89 | 0.57 | SE | KOUN\_1G5 | -49.78 | 0.20 |
| MA | SELING4 | -256.89 | 0.57 | SE | KOUN\_1G1 | -49.78 | 0.20 |
| MA | VICABO1G | -258.05 | 0.43 | SE | KOUN\_1G3 | -49.78 | 0.20 |
| MA | BALBIDG1 | -258.97 | 0.40 | SE | KOUN\_1G6 | -49.78 | 0.20 |
| MA | BALBIDG2 | -258.97 | 0.40 | SE | CAPDB11A | -50.33 | 0.20 |

Table 103 – Machines in phase opposition – Mode 2 – Base case (peak load)

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

Figure 16 - Mode shape graph of mode 3 – Base case (peak load)

| Machines in Phase Opposition |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- |
| Country | Machine | Angle | Contribution | Country | Machine | Angle | Contribution |
| SE | SENDOU1G | -249.33 | 0.42 | NI | DELTAG18 | -83.74 | 0.05 |
| SE | BELAIR2G | -248.06 | 0.40 | NI | DELTAG17 | -83.74 | 0.05 |
| SE | BELAIR1G | -248.06 | 0.40 | NI | DELTAG20 | -83.74 | 0.05 |
| SE | CAPDB19A | -247.88 | 0.39 | NI | DELTAG19 | -83.74 | 0.05 |
| SE | B\_AIRG61 | -248.67 | 0.39 | NI | DELTAG16 | -83.74 | 0.05 |
| SE | B\_AIRG62 | -248.67 | 0.39 | NI | DELTAG04 | -84.01 | 0.05 |
| SE | KOUN\_1G1 | -248.13 | 0.39 | NI | DELTAG05 | -84.01 | 0.05 |
| SE | KOUN\_1G4 | -248.13 | 0.39 | NI | DELTAG06 | -84.01 | 0.05 |
| SE | KOUN\_1G7 | -248.13 | 0.39 | NI | DELTAG03 | -84.01 | 0.05 |
| SE | KOUN\_1G2 | -248.13 | 0.39 | NI | AFAMGT20 | -83.74 | 0.05 |
| SE | KOUN\_1G3 | -248.13 | 0.39 | NI | AFAMGT19 | -83.74 | 0.05 |
| SE | KOUN\_1G5 | -248.13 | 0.39 | NI | DELTAG08 | -83.60 | 0.05 |
| SE | KOUN\_1G6 | -248.13 | 0.39 | NI | DELTAG07 | -83.60 | 0.05 |
| SE | CAPDB11A | -248.28 | 0.39 | NI | DELTAG09 | -83.60 | 0.05 |
| SE | CAPDB144 | -248.84 | 0.39 | NI | AFAMGT15 | -83.76 | 0.05 |
| SE | CAPDB145 | -248.84 | 0.39 | NI | AFAMGT16 | -83.76 | 0.05 |
| SE | GTI\_113A | -247.95 | 0.39 | NI | AFAMGT17 | -83.76 | 0.05 |
| SE | GTI\_111A | -247.73 | 0.37 | NI | AFAMGT18 | -83.76 | 0.05 |
| GU | TOMBO5G3 | -241.34 | 0.37 | NI | AFAMGT13 | -83.48 | 0.05 |
| GU | TOMBO5G1 | -241.34 | 0.37 | NI | AFAMGT14 | -83.48 | 0.05 |
| GU | TOMBO5G2 | -241.34 | 0.37 | NI | KWALCC3 | -81.41 | 0.04 |
| GU | TOMBO3G4 | -241.74 | 0.37 | NI | CALABGT2 | -80.49 | 0.04 |
| GU | MANEAHG1 | -242.07 | 0.37 | NI | CALABGT1 | -80.49 | 0.04 |
| GU | MANEAHG2 | -242.07 | 0.37 | NI | CALABGT3 | -80.49 | 0.04 |
| GU | MANEAHG3 | -242.07 | 0.37 | NI | CALABGT5 | -80.49 | 0.04 |

Table 104 – Machines in phase opposition – Mode 3 – Base case (peak load)

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

These modes could be identified also in time domain simulations. Figures here
below show the oscillations present in each mode.

Figure illustrates the phase opposition found in Mode 1, after a three-phase short
circuit at Tobene 225 kV bus bar in Senegal during 100 ms. The oscillation period of
mode 1 is about 2 seconds, its damping is not sufficient and the figure shows a clear
phase opposition of machines Sendou (Senegal) and Akosombo (Ghana). It was
confirmed by mode shape graph (see Figure ).

Figure 47 – Oscillations - Mode 1 – Base case (peak load)

To identify mode 2 in the dynamic simulations, a three-phase short circuit was
performed at Manantali 225 kV bus bar (Mali) during 100 ms. Figure shows the
oscillations.

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

Figure 48 – Oscillations - Mode 2 – Base case (peak load)

Here, the period is around 1 second. A phase opposition between Felou (Mali) and
Sendou (Senegal) units is shown, and its damping is not acceptable.

Another three-phase fault was performed to visualize mode 3. The node Birnin
Kebbi 330 kV (Nigeria) was chosen for simulation of a 100 ms short-circuit. Figure
illustrates the system response. The period of this mode is about 2.8 seconds. The
figure shows phase opposition between Sendou (Senegal) and Delta (Nigeria) units
and its damping is not sufficient.

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

In a general way, PSS should be installed on every large new unit in the system.
Also the biggest units of each country should be equipped with PSS.

Figure 49 – Oscillations - Mode 3 – Base case (peak load)

To check that improvement is feasible, PSS were installed on the machines in Table
. The two best sites in Nigeria were equipped. Other big machines in Nigeria were
selected, and machines in Guinea and Senegal because they participate to the modes
examined above.

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

| Units | Country |
| --- | --- |
| Geregu | Nigeria |
| Kaleta | Guinea |
| Sendou | Senegal |
| Ross Betio | Senegal |
| Jebba | Nigeria |
| Alaoji | Nigeria |
| Calaba | Nigeria |
| Eayen | Nigeria |

Table 105 – Machines with PSS to improve damping

After installation of PSS on these units, the damping was calculated again. Table
10614 retains the two last modes whose damping is still below 5%. Their damping is
now above 3% which is the minimum value recommended by the CIGRE task force
for system stability. The mode whose damping was about 0.5% is now damped at
4.5%.

| Mode | Real | Imaginary | ζ(%) | Freq(Hz) |
| --- | --- | --- | --- | --- |
| 1 | -0.186 | 6.167 | 3.01% | 0.982 |
| 2 | -0.143 | 3.192 | 4.47% | 0.508 |

Table 10614 - Characteristics of the least damped modes after PSS installation – Base case (peak load)

To visualize the improvement, a three-phase short circuit at Eyaen 330 kV was
simulated during 50 ms and Figure compares the units‟ oscillations between the
system with and without PSS. It clearly shows the action of PSS. This damping
could be even better with the appropriate tuning of the PSS parameters.

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

\[SC\_EYAEN\_NOPSS\] MACHINE : GEREGGT1 SPEED Unit : Hz
\[SC\_EYAEN\_+PSS\] MACHINE : GEREGGT1 SPEED Unit : Hz
Hz

\[SC\_EYAEN\_NOPSS\] MACHINE : AKOSOMG1 SPEED Unit : Hz
\[SC\_EYAEN\_+PSS\] MACHINE : AKOSOMG1 SPEED Unit : Hz
Hz

| Mode | Real | Imaginary | ζ(%) | Freq(Hz) |
| --- | --- | --- | --- | --- |
| 1 | -0.014 | 4.979 | 0.28% | 0.793 |
| 2 | -0.056 | 4.706 | 1.19% | 0.749 |
| 3 | -0.041 | 3.362 | 1.23% | 0.535 |
| 4 | -0.082 | 2.416 | 3.38% | 0.385 |
| 5 | -0.221 | 4.516 | 4.90% | 0.719 |

Table 10715 - Characteristics of the least damped modes – Scenario 2 (peak load)

With HERCULES, the eigenvalues of Scenario 2, peak load condition, were
calculated. Table 10715 shows the modes with damping coefficient lower than 5%.

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

As also happened in the Base case, this scenario has the least damped modes related
to inter-area oscillations. This analysis will present the first three ones:

• Mode 1 is an inter-area oscillation between Mali and Senegal.

• Mode 2 is an inter-area oscillation between Burkina Faso and Ivory Coast.
Mode 3 is an inter-area oscillation between Ghana/Ivory Coast/Togo/Benin and

• Mode 3 is an inter-area oscillation between Ghana/Ivory Coast/Togo/Benin and
Guinea/Sierra Leone.

The tables and charts below illustrate the modes.

Figure 51 - Mode shape graph of mode 1 – Scenario 2 (peak load)

| Machines in Phase Opposition |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- |
| Country | Machine | Angle | Contribution | Country | Machine | Angle | Contribution |
| SE | SENDOU1G | -176.11 | 0.29 | MA | MANAN11A | -15.13 | 0.34 |
| SE | CAPDB13A | -167.51 | 0.22 | MA | MANAN13A | -15.13 | 0.34 |
| SE | CAPDB19A | -167.54 | 0.22 | MA | MANAN12A | -15.13 | 0.34 |
| SE | GTI\_113A | -167.09 | 0.22 | MA | MANAN14A | -15.13 | 0.34 |
| SE | CAPDB1G3 | -167.32 | 0.22 | MA | MANAN15A | -15.13 | 0.34 |
| SE | TOBIN\_1G | -168.27 | 0.21 | MA | SELING1 | -19.72 | 0.33 |
| SE | BELAIR1G | -168.42 | 0.21 | MA | SELING2 | -19.72 | 0.33 |
| SE | BELAIR2G | -168.42 | 0.21 | MA | SELING3 | -19.72 | 0.33 |
| SE | GTI\_111A | -165.40 | 0.21 | MA | SELING4 | -19.72 | 0.33 |
| SE | KOUN\_1G1 | -168.20 | 0.21 | MA | FELOU\_1G | -4.59 | 0.32 |
| SE | KOUN\_1G3 | -168.20 | 0.21 | MA | FELOU\_3G | -4.59 | 0.32 |
| SE | KOUN\_1G4 | -168.20 | 0.21 | MA | FELOU\_2G | -4.59 | 0.32 |
| SE | KOUN\_1G2 | -168.20 | 0.21 | MA | DARSAL8G | -18.36 | 0.28 |
| SE | KOUN\_1G5 | -168.20 | 0.21 | MA | DARSAL1G | -18.59 | 0.28 |
| SE | KOUN\_1G6 | -168.20 | 0.21 | MA | DARASLA6 | -18.59 | 0.28 |
| SE | KOUN\_1G7 | -168.20 | 0.21 | MA | DARASLA5 | -18.56 | 0.28 |
| SE | WIND\_1G | -162.41 | 0.21 | MA | DARASLA7 | -18.56 | 0.28 |
| SE | CAPDB11A | -168.90 | 0.20 | MA | VICABO1G | -18.80 | 0.28 |
| SE | KOUDI\_1G | -162.58 | 0.10 | MA | ALBATR1G | -8.41 | 0.27 |
| SE | KOUDI\_2G | -162.58 | 0.10 | MA | SOPAM\_01 | -18.60 | 0.27 |

Table 10816 – Machines in phase opposition – Mode 1 – Scenario 2 (peak load)

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

Figure 52 - Mode shape graph of mode 2 – Scenario 2 (peak load)

| Machines in Phase Opposition |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- |
| Country | Machine | Angle | Contribution | Country | Machine | Angle | Contribution |
| BU | 4KOS3\_11 | -136.47 | 0.91 | CI | 2032TAAB | 1.83 | 0.45 |
| BU | 4KOMPI26 | -137.28 | 0.87 | CI | 2033TAAB | 1.79 | 0.44 |
| BU | 4KOMPI16 | -137.28 | 0.87 | CI | 2034TAAB | 1.79 | 0.44 |
| BU | 4KOS5\_11 | -141.26 | 0.87 | CI | 2043KOSS | 2.69 | 0.40 |
| BU | 4KOS4\_11 | -141.26 | 0.87 | CI | 2042KOSS | 2.69 | 0.40 |
| BU | 4KOS6\_11 | -140.20 | 0.86 | CI | 2044KOSS | 2.61 | 0.40 |
| BU | 4BAGRE26 | -137.10 | 0.80 | CI | 2093BUYO | -0.65 | 0.33 |
| BU | 4BAGRE16 | -137.07 | 0.80 | CI | 2094BUYO | -0.66 | 0.33 |
| BU | 4OUA23\_5 | -149.89 | 0.78 | CI | 2NEWCC-1 | -2.03 | 0.33 |
| BU | KOMSILG5 | -136.18 | 0.77 | CI | 2027VRID | -2.35 | 0.33 |
| BU | KOMSILG1 | -136.18 | 0.77 | CI | 2028VRID | -2.34 | 0.32 |
| BU | KOMSILG3 | -136.17 | 0.77 | CI | 20NTAG82 | -2.48 | 0.32 |
| BU | KOMSILG4 | -136.17 | 0.77 | CI | 20NGTAG8 | -2.48 | 0.32 |
| BU | KOMSILG2 | -135.50 | 0.74 | CI | 2029VRID | -2.55 | 0.32 |
| BU | 4OUA24\_5 | -140.70 | 0.70 | CI | 20NTAG83 | -2.52 | 0.32 |
| BU | 4OUA25\_5 | -140.70 | 0.70 | CI | FAYE\_H\_G | 1.93 | 0.32 |
| BU | 4BOB25\_5 | -124.79 | 0.32 | CI | 2023VGT2 | -3.09 | 0.31 |
| BU | 4BOB22\_5 | -122.47 | 0.27 | CI | 2023VGT1 | -3.09 | 0.31 |
| BU | 4BOB21\_5 | -122.52 | 0.27 | CI | 2501AZI | -2.80 | 0.31 |

Table 10917 – Machines in phase opposition – Mode 2 – Scenario 2 (peak load)

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

Figure 532 - Mode shape graph of mode 3 – Scenario 2 (peak load)

| Machines in Phase Opposition |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- |
| Country | Machine | Angle | Contribution | Country | Machine | Angle | Contribution |
| GH | AKOSOMG2 | -268.52 | 0.22 | GU | TOMBO5G3 | -56.26 | 1.26 |
| GH | AKOSOMG3 | -268.52 | 0.22 | GU | TOMBO5G1 | -56.26 | 1.26 |
| GH | AKOSOMG4 | -268.52 | 0.22 | GU | TOMBO5G2 | -56.26 | 1.26 |
| GH | AKOSOMG5 | -268.52 | 0.22 | GU | GRCHUTG3 | -54.46 | 1.25 |
| GH | AKOSOMG1 | -268.52 | 0.22 | GU | GRCHUTG4 | -54.45 | 1.25 |
| GH | AKOSOMG6 | -268.52 | 0.22 | GU | DONKEAG1 | -53.08 | 1.24 |
| GH | KPONGHG2 | -267.24 | 0.20 | GU | DONKEAG2 | -53.08 | 1.24 |
| GH | KPONGHG4 | -267.24 | 0.20 | GU | GRCHUTG2 | -54.41 | 1.24 |
| GH | KPONGHG1 | -267.24 | 0.20 | GU | GRCHUTG1 | -54.41 | 1.24 |
| GH | KPONGHG3 | -267.24 | 0.20 | GU | TOMBO3G4 | -56.77 | 1.22 |
| TB | 3NEWIPP | -268.83 | 0.13 | GU | TOMBO3G2 | -56.77 | 1.22 |
| CI | 2023VGT1 | -263.96 | 0.11 | GU | TOMBO3G3 | -56.76 | 1.22 |
| CI | 2023VGT2 | -263.96 | 0.11 | GU | TOMBO3G1 | -56.76 | 1.22 |
| CI | 2027VRID | -268.52 | 0.11 | GU | MANEAHG1 | -56.94 | 1.20 |
| CI | 2028VRID | -268.04 | 0.11 | GU | GARAFIG1 | -54.01 | 1.16 |
| CI | 20NTAG82 | -268.68 | 0.11 | GU | GARAFIG2 | -54.01 | 1.16 |
| CI | 20NGTAG8 | -268.68 | 0.11 | GU | GARAFIG3 | -54.01 | 1.16 |
| CI | 2029VRID | -268.19 | 0.11 | SL | BUMBU1G2 | -51.26 | 1.09 |
| CI | 20NTAG83 | -268.66 | 0.11 | SL | BUMBU1G1 | -51.26 | 1.09 |
| TB | 3061NANG | -269.08 | 0.09 | SL | BLACKHG3 | -53.71 | 0.96 |
| TB | 3062NANG | -269.08 | 0.09 | SL | BLACKHG1 | -53.71 | 0.96 |
| CI | 2501AZI | -265.91 | 0.07 | SL | BLACKHG2 | -53.71 | 0.96 |
| TB | MA\_GLE3G | -269.57 | 0.05 | SL | GOMA\_HG1 | -50.34 | 0.79 |

Table 11018 – Machines in phase opposition – Mode 3 – Scenario 2 (peak load)

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

Time domain simulations allowed observing these modes. The phase opposition
found in mode 1 is illustrated in Figure 543. The disturbance chosen was a threephase short circuit at Manantali 225 kV bus bar (Mali) during 100 ms.

Figure 543 – Oscillations - Mode 1 – Scenario 2

This figure shows phase opposition of Sendou (Senegal) and Manantali (Mali) units.
It was confirmed by mode shape graph. The period of oscillations is around 1.2
seconds. Its damping is unacceptable.

A three-phase short circuit was executed at Zagtouli 225 kV bus bar (Burkina Faso)
during 100 ms in order to observe mode 2. Figure shows the oscillations.

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

Figure 55 – Oscillations - Mode 2 – Scenario 2 (peak load)

Here, the period is around 1.4 second. A phase opposition between Kossodo
(Burkina Faso) and Taabo (Ivory Coast) units can be observed and its damping is
not sufficient. This mode is visible though the oscillations present two or more
modes overlapping.

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

Figure 56 – Oscillations - Mode 3 – Scenario 2 (peak load)

The period of this mode is about 1.9 seconds. The figure shows phase opposition
between Akosombo (Ghana) and Tombo (Guinea) units and its damping is not
sufficient. Again, there are two or more modes overlapping but the oscillation is
visible.

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

3.4.5.3. 2015 OFF PEAK LOAD: BASE CASE

In this scenario, the modes lower than 6.0% are showed in the following table.

| Mode | Real | Imaginary | ζ(%) | Freq(Hz) |
| --- | --- | --- | --- | --- |
| 1 | -0.042 | 3.528 | 1.19% | 0.562 |
| 2 | -0.039 | 2.640 | 1.49% | 0.420 |
| 3 | -0.487 | 10.564 | 4.61% | 1.682 |
| 4 | -0.473 | 8.926 | 5.29% | 1.421 |
| 5 | -0.329 | 5.705 | 5.75% | 0.908 |
| 6 | -0.652 | 11.273 | 5.77% | 1.795 |

Table 111 - Characteristics of the least damped modes – Base case (off-peak load)

The first three modes are under 5% and will be analyzed here:

• Mode 1 is an inter-area oscillation between Ghana/Ivory Coast and
Senegal/Guinea.
Mode 2 is an inter-area oscillation between Senegal/Guinea and Nigeria.

• Mode 2 is an inter-area oscillation between Senegal/Guinea and Nigeria.
Mode 3 is an electromechanical oscillation between machine ZINDCC1G in

• Mode 3 is an electromechanical oscillation between machine ZINDCC1G in
Niger and SHIRGH1/ SHIRGH2 in Nigeria.
The tables and charts below illustrate the modes.

The tables and charts below illustrate the modes.

The mode shape graph in Figure 574demonstrates the phase opposition between the
two groups of machines for mode 1. It is an oscillation between Ghana/Ivory Coast
and Senegal/Guinea. Table 11219 helps to understand better the graph. The module
of the arrow gives the contribution of the machine to the oscillation and its angle
gives the phase of the contribution in the oscillation.

The same graphs and tables are provided for mode 2.

Figure 574 - Mode shape graph of mode 1 – Base case (off-peak load)

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

| Machines in Phase Opposition |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- |
| Country | Machine | Angle | Contribution | Country | Machine | Angle | Contribution |
| GH | DOMIT1G1 | -135.38 | 0.34 | GU | KALETAG1 | 74.53 | 0.58 |
| GH | DOMIT1G2 | -135.38 | 0.34 | GU | KALETAG2 | 74.53 | 0.58 |
| GH | ABOAT1G1 | -135.33 | 0.33 | GU | KALETAG3 | 74.53 | 0.58 |
| GH | ABOAT1G2 | -135.33 | 0.33 | GU | DONKEAG1 | 73.99 | 0.55 |
| GH | ABOAT2G1 | -135.33 | 0.33 | GU | DONKEAG2 | 73.99 | 0.55 |
| GH | ABOAT1ST | -134.16 | 0.30 | GU | GRCHUTG1 | 72.64 | 0.53 |
| GH | ABOA3CC1 | -135.44 | 0.27 | GU | GARAFIG1 | 73.20 | 0.52 |
| CI | 2029VRID | -135.51 | 0.26 | GU | TOMBO5G3 | 69.14 | 0.52 |
| CI | 20NGTAG8 | -133.90 | 0.25 | GU | TOMBO5G2 | 69.14 | 0.52 |
| CI | 20NTAG82 | -133.90 | 0.25 | GU | TOMBO3G4 | 69.61 | 0.50 |
| CI | 2027VRID | -134.10 | 0.25 | GU | MANEAHG1 | 69.53 | 0.50 |
| GH | AKOSOMG1 | -131.22 | 0.25 | GB | GBISSEQG | 65.77 | 0.49 |
| GH | AKOSOMG2 | -131.22 | 0.25 | GA | GAMB\_EQG | 63.71 | 0.48 |
| CI | 2NEWCC-1 | -134.16 | 0.25 | SE | CAPDB19A | 66.41 | 0.48 |
| CI | 2NEWCC-2 | -134.16 | 0.25 | SE | BELAIR1G | 64.48 | 0.47 |
| CI | 20NTAG83 | -133.87 | 0.25 | SE | BELAIR2G | 64.48 | 0.47 |
| CI | 2032TAAB | -128.73 | 0.25 | SE | GTI\_113A | 66.25 | 0.47 |
| GH | SASO2CC1 | -136.56 | 0.25 | SE | B\_AIRG61 | 64.47 | 0.47 |
| GH | BUI\_G1 | -129.87 | 0.24 | SE | B\_AIRG62 | 64.47 | 0.47 |
| CI | 2033TAAB | -130.09 | 0.24 | SE | KOUN\_1G1 | 65.93 | 0.47 |
| GH | TEMAT1G2 | -137.37 | 0.24 | SE | KOUN\_1G2 | 65.93 | 0.47 |
| GH | KPONGHG1 | -126.60 | 0.24 | SE | KOUN\_1G3 | 65.93 | 0.47 |
| GH | KPONGHG2 | -126.60 | 0.24 | SE | KOUN\_1G4 | 65.93 | 0.47 |
| GH | KPONGHG3 | -126.60 | 0.24 | SE | KOUN\_1G5 | 65.93 | 0.47 |
| GH | KPONGHG4 | -126.60 | 0.24 | SE | CAPDB144 | 64.63 | 0.47 |

Table 11219 - Machines in phase opposition - Mode 1 - Base case off-peak load

Figure 58 - Mode shape graph of mode 2 - Base case (off-peak load)

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

| Machines in Phase Opposition |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- |
| Country | Machine | Angle | Contribution | Country | Machine | Angle | Contribution |
| GU | KALETAG1 | -72.04 | 0.46 | NI | DELTAG18 | 77.09 | 0.06 |
| GU | KALETAG2 | -72.04 | 0.46 | NI | DELTAG19 | 77.09 | 0.06 |
| GU | KALETAG3 | -72.04 | 0.46 | NI | DELTAG20 | 77.09 | 0.06 |
| GU | DONKEAG1 | -73.14 | 0.45 | NI | AFAMGT19 | 77.71 | 0.06 |
| GU | DONKEAG2 | -73.14 | 0.45 | NI | AFAMGT20 | 77.71 | 0.06 |
| GU | TOMBO5G3 | -78.13 | 0.44 | NI | AFAMGT15 | 77.64 | 0.06 |
| GU | TOMBO5G2 | -78.13 | 0.44 | NI | AFAMGT13 | 78.01 | 0.06 |
| GU | GRCHUTG1 | -75.81 | 0.44 | NI | AFAMGT14 | 78.01 | 0.06 |
| GU | GARAFIG1 | -75.44 | 0.43 | NI | DELTAG03 | 78.11 | 0.06 |
| GU | TOMBO3G4 | -78.01 | 0.43 | NI | DELTAG04 | 78.11 | 0.06 |
| GU | MANEAHG1 | -78.12 | 0.43 | NI | DELTAG05 | 78.11 | 0.06 |
| GB | GBISSEQG | -80.72 | 0.42 | NI | EGBINST1 | 75.89 | 0.06 |
| GA | GAMB\_EQG | -82.42 | 0.42 | NI | EGBINST2 | 75.89 | 0.06 |
| SE | CAPDB19A | -80.85 | 0.42 | NI | EGBINST3 | 75.89 | 0.06 |
| SE | BELAIR1G | -82.34 | 0.42 | NI | EGBINST4 | 75.89 | 0.06 |
| SE | BELAIR2G | -82.34 | 0.42 | NI | EGBINST5 | 75.89 | 0.06 |
| SE | KOUN\_1G1 | -81.20 | 0.42 | NI | EGBINST6 | 75.89 | 0.06 |
| SE | KOUN\_1G2 | -81.20 | 0.42 | NI | KWALCC3 | 81.36 | 0.06 |
| SE | KOUN\_1G3 | -81.20 | 0.42 | NI | IBOMGT01 | 82.33 | 0.06 |
| SE | KOUN\_1G4 | -81.20 | 0.42 | NI | IBOMGT02 | 82.33 | 0.06 |
| SE | KOUN\_1G5 | -81.20 | 0.42 | NI | IBOMGT03 | 82.76 | 0.06 |
| SE | B\_AIRG61 | -82.36 | 0.42 | NI | CALABGT3 | 82.68 | 0.06 |
| SE | B\_AIRG62 | -82.36 | 0.42 | NI | CALABGT4 | 82.68 | 0.06 |
| SE | GTI\_113A | -81.17 | 0.41 | NI | CALABGT5 | 82.68 | 0.06 |
| SE | CAPDB144 | -82.18 | 0.41 | NI | ALAOJGT4 | 82.68 | 0.06 |
| SE | CAPDB145 | -82.18 | 0.41 | NI | ALAOJGT3 | 82.72 | 0.06 |

Table 113 - Machines in phase opposition - Mode 2 - Base case (off-peak load)

The time domain simulations can also show these modes. Figures here below show
the oscillations present in each mode.

To illustrate mode 1, a three-phase short-circuit was simulated at Akosombo 161 kV
bus bar during 100 ms. The oscillation period of mode 1 is about 1.7 seconds, its
damping is not sufficient and the figure shows a clear phase opposition of machines
Kaleta (Guinea) and Domini (Ghana).

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

Figure59– Oscillations - Mode 1 – Base case (off-peak load)

To identify mode 2 in the dynamic simulations, a three-phase short circuit was
performed at Tobene 225 kV bus bar (Senegal) during 100 ms. Table 907 shows the
oscillations.

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

Figure 605– Oscillations - Mode 2 – Base case off-peak load

Mode 3 corresponds to the electromechanical oscillations of machines located in
Niger and Nigeria. The next figures illustrate the shape graph representing the
participation factor of each unit to this mode (coming from right eigenvectors). The
magnitude of each vector is proportional to the participation coefficient of the
corresponding machine

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

Figure 616 - shape graph of mode 3 – Base case (off-peak load)

approval

to third parties is forbidden without prior written

ny duplication or transmission

Figure 627 – Contribution to shape graph of mode 3 – Base case (off-peak load)

This document is the property of Tractebel Engineering S.A. A

MP-WAPP/4NT/221291/002/00 October 2011 198/273

* * *

3.4.5.4. 2015 OFF PEAK LOAD: SCENARIO 2

The eigenvalues for this scenario were calculated using HERCULES. The modes
with damping lower than 6.0% are showed in the table below.

| Mode | Real | Imaginary | ζ(%) | Freq(Hz) |
| --- | --- | --- | --- | --- |
| 1 | -0.105 | 4.968 | 2.11% | 0.791 |
| 2 | -0.474 | 8.916 | 5.30% | 1.420 |
| 3 | -0.414 | 7.571 | 5.46% | 1.206 |
| 4 | -0.645 | 11.634 | 5.54% | 1.853 |
| 5 | -0.399 | 7.133 | 5.58% | 1.136 |

Table 114 - Characteristics of the least damped modes - Scenario 2 (off-peak load)

This analysis will present only the lowest mode. The others are over 5.0% and are
acceptable. Mode 1 is an inter-area oscillation between Guinea/Senegal and Ivory
Coast. The tables and charts below illustrate this mode.

Figure 638 - Mode shape graph of mode 1 – Scenario 2 off-peak load

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

| Machines in Phase Opposition |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- |
| Country | Machine | Angle | Contribution | Country | Machine | Angle | Contribution |
| GU | DONKEAG2 | -100.47 | 0.64 | CI | 2033TAAB | 54.70 | 0.57 |
| GU | DONKEAG1 | -100.47 | 0.64 | CI | 2032TAAB | 54.80 | 0.56 |
| GU | GRCHUTG1 | -99.72 | 0.64 | CI | 2043KOSS | 60.19 | 0.52 |
| GU | TOMBO5G3 | -105.07 | 0.61 | CI | 2044KOSS | 60.08 | 0.50 |
| GU | TOMBO5G2 | -105.07 | 0.61 | CI | 2029VRID | 50.19 | 0.40 |
| GU | GARAFIG1 | -98.16 | 0.60 | CI | 2093BUYO | 55.26 | 0.37 |
| GU | MANEAHG2 | -104.38 | 0.57 | CI | 20NGTAG8 | 52.95 | 0.36 |
| GU | MANEAHG1 | -104.38 | 0.57 | CI | 20NTAG82 | 52.95 | 0.36 |
| GU | TOMBO3G4 | -104.25 | 0.57 | CI | 20NTAG83 | 52.89 | 0.36 |
| SL | BUMBU1G1 | -99.42 | 0.54 | CI | 2NEWCC-2 | 53.60 | 0.36 |
| SL | BLACKHG1 | -98.69 | 0.40 | CI | 2NEWCC-1 | 53.60 | 0.36 |
| SL | BLACKHG2 | -98.69 | 0.40 | CI | 2025VRID | 52.73 | 0.36 |
| SL | BLACKHG3 | -98.69 | 0.40 | CI | 2024VRID | 52.79 | 0.35 |
| SL | GOMA\_HG2 | -87.92 | 0.29 | CI | 2027VRID | 52.96 | 0.35 |
| SL | GOMA\_HG1 | -87.92 | 0.29 | CI | FAYE\_H\_G | 57.68 | 0.35 |

Table 115 - Machines in phase opposition - Mode 1 - Scenario 2 (off-peak load)

This inter-area oscillation can be seen in the time domain simulations. A three-phase
short-circuit was made at Taabo 225 kV during 100 ms.

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

The small signal stability analysis detected several inter-area oscillations for both
cases studied. The least damped modes were all related to inter-area oscillations:

3.4.5.5. CONCLUSIONS OF THE SMALL SIGNAL STABILITY ANALYSIS

Figure 64– Oscillations - Mode 1 – Scenario 2 (off-peak load)

• between Ghana/Ivory Coast and Senegal/Guinea,
between Mali and Senegal,

• between Senegal/Guinea and Nigeria,
between Burkina Faso and Ivory Coast,

• between Burkina Faso and Ivory Coast,

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

• between Ghana/Ivory Coast/Togo/Benin and Guinea/Sierra Leone,
between Niger (zone center-east) and Nigeria,

• between Niger (zone center-east) and Nigeria,
between Guinea/Senegal and Ivory Coast.

• between Guinea/Senegal and Ivory Coast.
The main conclusion is that there is a risk of instability due to inter-area oscillations.

The main conclusion is that there is a risk of instability due to inter-area oscillations.
In order to limit this risk, it is recommended to:

• install PSS on all new large units to be commissioned in the system,
check if PSS do not already exist on the biggest machines of every country and,

• check if PSS do not already exist on the biggest machines of every country and,
if not, install PSS there,
Stress the importance of inter-area oscillations analysis in detailed feasibility

• Stress the importance of inter-area oscillations analysis in detailed feasibility
studies of future interconnections,
The importance of such oscillations on the stability also recommends undertaking a

The importance of such oscillations on the stability also recommends undertaking a
deeper data collection and looking for all accurate information on the dynamics of
the main and biggest power units of the system. The goal is to build a more accurate
dynamic model of the WAPP system to be able to perform such advanced
simulations.

The quality of such analysis depends highly on the quality of the dynamic model
used in the calculations. In this case, many assumptions were done for building the
dynamic model, by lack of information in many countries. If the model quality is
good enough to identify the risks of inter-area oscillations, it is not accurate enough
to perform a detailed PSS tuning analysis.

Finally, the installation of WAMS (Wide Area Monitoring Systems) is
recommended to detect and observe the inter-area oscillations. Moreover, it would
be very useful to confirm they are correctly damped after PSS installations.

3.4.6. Dynamic studies: Transient stability

The critical clearing times (CCT) were calculated for faults at all HV nodes from
760 to 90 kV close from generation units, on all 2015 situations. All results are in
appendix.

Akosombo unit 1 in Ghana was chosen as reference machine for the analysis. Any
machine whose angular position is different from plus or minus 360 degrees with
Akosombo‟s angular position was declared as losing synchronism.

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

As visible in the tables, for the Base case at peak load, all CCT are above 100 ms
except for two nodes in Nigeria: Eyaen and Alaoji 330 kV. Figure and Figure 669
show the stability of the system for a 80 ms short-circuit at Eyaen 330 kV (Nigeria)
while there are losses of synchronism if it is cleared after 100 ms.

The values of CCT are influenced by the small signal stability of the system. They
can increase of 0 ms to important values if the small signal stability is improved. To
check the possible improvement, the same CCT were computed for a system with
PSS on the machines indicated in Table . The results are given in Table and Table .

The most spectacular variation in this Base case is for a short circuit at Ikot Abasi
330 kV bus bar, in Nigeria: the CCT increased of 116 ms. More important, the CCT
that were below 100 ms, for short-circuits at Eyaen and Alaoji, are now above 100
ms with the PSS.

Table and Table list the results for Scenario 2 at peak load. The conclusion is that
the stability is reduced compared with the Base case. It is normal given that the
system is less interconnected.

More nodes present CCT below 100 ms but the tables show that the machine losing
synchronism is remote from the fault, which is a good indication that the problem is
more related to small signal stability than transient stability. Here again, PSS
installation and proper tuning should increase the stability and the CCT should reach
values above 100 ms.

Table and Table list the results for off peak load situations for the Base case and
Scenario 2, for faults with line tripping. Here again, some values are below 100 ms
but the installation of PSS should help them pass above 100 ms.

If the installation of PSS can improve the transient stability of the system, it should
clearly be accomplished. Nevertheless, if such system can reduce the oscillations
that have a negative effect on the transient stability, it has no impact on the transient
stability limit and it will not prevent the machines from losing synchronism when
this limit is reached.

To prevent the instability propagation in cases of loss of synchronism, the system
should be split temporarily, to resynchronize after both parts stabilized. To this
purpose, it is recommended to install out of step protections on the main and longest
interconnections.

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

Figure 65 – Base case (peak load) – 80 and 100 ms 3ph short-circuit at Eyaen 330 kV
(Nigeria): voltage and machine angular position at Eyaen

Figure 669 – Base case (peak load) – 80 and 100 ms 3ph short-circuit at Eyaen 330 kV
(Nigeria): machines angular positions at Monrovia and Manantali

to third parties is forbidden without prior written approval
ny duplication or transmission
Tractebel Engineering S.A. A
This document is the property of

* * *

3.4.7. Dynamic security assessment: unit contingencies

For both 2015 scenarios, at peak and off peak load, the loss of each unit of the
system was simulated dynamically. The stability of the system was checked and
particular attention was brought to frequency transients.

The contingency provoking the largest frequency transient is the loss of one GT and
the power of half a ST in the combined cycle of Okpai (Kwale) in Nigeria.

For the Base case, at peak load condition, Figure 6710 and Figure illustrate the
network behavior for this contingency. The active power production of GT1
disappears from the system balance, and the active power production of the ST
slowly decreases to half its initial level with the steam transient. The average
frequency of the network decreases down to 49.3 Hz before recovering just below
49.9 Hz. The active power of GT2 at Okpai CC and the machines speed in the
network show oscillations. In particular, an inter-area oscillation is visible with
machines responses in phase opposition from Nigeria to Senegal. This inter-zonal
oscillation was described in the small signal stability analysis.

For the Base case at peak load condition, another incident must be mentioned: the
loss of Sendou coal unit. This contingency represents a loss of 125 MW for Senegal.
Consequently, the same amount of power is unblocked on the spinning reserve and
an important part of it flows from the other countries to Senegal. Consequently, the
flow on the lines to Senegal increases and the maximum transfer capacity is
exceeded, causing the system instability. Figure and Figure depicts the system
response and the voltage collapse. The flow value reaches approximately 175 MW
on the 225 kV line from Manantali while the tables in the maximum transfer
capacity analysis (N condition) indicate a maximum of 160 MW on this line. There
is a voltage collapse in Senegal after the machines, one after the other, try to inject
more reactive power to support the voltages and see their reactive power production
limited by the over-excitation limiter.

without prior written approval
to third parties is forbidden
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

Figure 6710 – Base case (peak load): Okpai GT+1/2ST contingency: power of GT2 and ST
at Okpai CC, and average network frequency

Figure 68 - Base case (peak load): Okpai GT+1/2ST contingency: machines speed and interarea oscillations

to third parties is forbidden without prior written approval
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

Figure 69 – Base case (peak load): Sendou coal unit contingency: active power flows on
interconnection lines towards Senegal

Figure 70 – Base case (peak load): Sendou coal unit contingency: voltages in and around
Senegal

to third parties is forbidden without prior written approval
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

For Scenario 2 at peak load condition, since Okpai CC is running, the most
constraining contingency is also the loss of a GT and half the power of the ST.
Figure and Figure illustrate the system responses to the contingency. It is visible
that the average system frequency drops down to 49.5 Hz before recovering up to
49.9 Hz. The response is more favorable than the one in the Base case because of the
reserve allocation. In this scenario, the reserve was shared among more units.

For what concerns the inter area oscillations, they are still present and even more
important. Because the system is less interconnected, it is more prone to experience
such type of oscillations.

For off peak load situations, for the Base case, the loss of one GT and half a ST at
Kwale provokes a frequency drop down to 49.5 Hz and recovers to 49.85 Hz. The
transient is illustrated in Figure and it is acceptable.

For off peak load situation for the Base case, one unit contingency provokes the loss
of stability: the wind farm in Senegal. It produces 60 MW and its loss provokes the
unblocking of the primary reserve in the WAPP system. Active power flows towards
Senegal increase to replace the loss of production, provoking the instability. This
situation is illustrated in Figure and Figure .

For off peak load situation for Scenario 2, the loss of one GT and half a ST at Kwale
provokes a frequency drop down to 49.5 Hz and recovers to 49.85 Hz. The transient
is illustrated in Figure and it is acceptable.

For off peak load situation for Scenario 2, no unit contingency provokes the loss of
stability.

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

Figure 71 – Scenario 2 (peak load): Okpai GT+1/2ST contingency: power of GT2 and ST at
Okpai CC, and average network frequency

Figure 72 – Scenario 2 (peak load): Okpai GT+1/2ST contingency: machines speed and
inter-area oscillations

to third parties is forbidden without prior written approval
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

\[LOSS\_KWALGT1\] MACHINE : KWALCC2 ACTIVE POWER Unit : MW
MW

\[LOSS\_KWALGT1\] MACHINE : KWALCC3 ACTIVE POWER Unit : MW
Hz

Figure 73 – Base case (off peak load): Okpai GT+1/2ST contingency: power of GT2 and ST
at Okpai CC, and average network frequency

\[LOSS\_KWALGT1\] MACHINE : KWALCC2 ACTIVE POWER Unit : MW
MW

\[LOSS\_KWALGT1\] MACHINE : KWALCC3 ACTIVE POWER Unit : MW

Figure 74 - Scenario 2 (off peak load): Okpai GT+1/2ST contingency: power of GT2 and ST
at Okpai CC, and average network frequency

\\mathrm{C C},

to third parties is forbidden without prior written approval
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

Figure 75 - Base case (off peak load): Wind farm contingency: active power flows on
interconnection lines towards Senegal

Figure 76 - Base case (off peak load): Wind farm contingency: voltages in and around
Senegal

to third parties is forbidden without prior written approval
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

3.4.8. Dynamic security assessment: Short-circuit on lines

In order to check the stability of the system, a three-phase fault with no impedance
and duration of 100 ms was executed on each line. The criteria checked were given
in the methodology.

2. Simulations
   The simulations were carried out for a total of 550 lines in the system
   of short- circuits were performed twice: a first time at 0.1% distance on the line and a
   second time at 99.9% distance. The analysis was done for the Base case and for
   Scenario 2, at peak and off peak load conditions.

Actually, the static security analysis has already showed that the N- 1 criterion is not
satisfied even for contingencies without faults. Here, in addition of the contingency,
there is a three- p hase fault. The system response will consequently be less
favourable, and all incidents already listed in the security analysis could be listed
here as well.

Among all the results, the problems detected can be classified in three categories:

• The voltage collapses due to the incapacity of the system to recover the voltage
after the drop provoked by the fault
The instabilities related to the maximum transfer capacities.

• The instabilities related to the maximum transfer capacities.
Figure presents the system response and the oscillations for a fault in the north of

Figure presents the system response and the oscillations for a fault in the north of
Nigeria. It illustrates the problems of inter-area oscillations. With the short-circuit,
the oscillations modes are excited and it reduces the system stability. In the situation
shown, the oscillations responses in Senegal are large enough to provoke the undervoltage protection activation at Ross Betio units in Dagan. With PSS, this
phenomenon would be avoided.

Figure illustrates the problem of voltage collapse. The sensitivity of Niger is
presented, with the system response and the voltage collapse in Niger for a fault in
the south of Nigeria. While the system recovers in Nigeria, it does not in Niger, even
though Niger is further from the fault. This phenomenon is typical from areas were
few generation units are in service. Typically, importing countries are concerned.
For this problem, it is important to keep a minimum amount of generation running to
ensure the voltage support. Otherwise, the installation of SVC is also a solution.

Finally, the last problem category, the maximum transfer capacity, will also be
illustrated in the next section. The problem is not related to the fault, but to the line
tripping and the consequences this tripping has in terms of flows redistribution. In
the scenarios investigated, this phenomenon was detected several times.

2 550 lines for the Base c
ase.

to third parties is forbidden without prior written approval
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

Figure 77 – Base case (peak load) - 3 phase short-circuit on line between Shiroro and
Gwagwalada (Nigeria). Machines oscillations in the system and under-voltage in Senegal

Figure 78 – Base case (peak load) - 3 phase short-circuit on line between Benin City and
Egbin (Nigeria). Voltage response in Nigeria and collapse in Niamey (Niger)

to third parties is forbidden without prior written approval
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

As a conclusion, the system does not support three phase faults anywhere. This
incident is very severe and it is not recommended to use it as a sizing incident for
planning studies.

Instead, it is recommended to set up defence schemes and protections to operate the
system without being able to support three phase faults, but being able to limit the
propagation of such incidents to the whole system in case instability would appear.
To this purpose, out-of-step protections should be installed on the interconnections
and other long lines, and UFLS and UVLS should be set up and/or harmonized in all
countries.

Finally the proportion of rotating loads at peak condition should be confirmed. The
dynamic load model used for this analysis is composed of 40% of rotating loads. It
is a high proportion and it influences the stability margins because in case of low
voltages, the motors start stalling and prevent the voltage to recover.

3.4.9. Dynamic security assessment: Maximum transfer capacities

The maximum transfer capacity is the maximum flow the system can support on a
line. This limit depends on several aspects, among others:

• The criteria applied to decide whether a situation is stable or not, acceptable or
not. If the criteria are related to operational criteria (like acceptable voltage
range, tolerated overloads,…) the maximum transfer capacity will be reduced
compared with the value that could be obtained when operating the system up to
the limit of stability (voltage collapse, frequency collapse and/or loss of
synchronism).
The contingencies to be supported by the system. The maximum transfer

synchronism).
• The contingencies to be supported by the system. The maximum transfer
capacity is higher without contingency. It is lower when the system has to
support a single phase fault, and even lower in case of three phase faults.
The computation scenario applied. The transfer capacity will be different

• The computation scenario applied. The transfer capacity will be different
according to the production plan set up in the computation scenario. The
operation of generation units close to the loads and to the interconnections has an
influence on the stability.
In this section, the criterion applied will be the intrinsic stability of the system. The

It is important to state that PSS were installed on the machines listed in Table to
improve the system damping. Without these PSS, the contingencies performed in the
analysis provoke oscillations reducing the stability margins. Given that the future
system damping will be acceptable, it is important to do this maximum transfer
capacity analysis with an acceptable damping.

In this section, the criterion applied will be the intrinsic stability of the system. The
behavior of the system is acceptable if it does not lead to any voltage collapse,
frequency collapse and/or loss of synchronism.

The contingencies to be supported will cover the tripping of any element (line,
transformer, machine) of the system without short circuit. As shown in the previous
section, the system does not support three phase faults everywhere. And when the
induction motors share in the load is not too important, a line tripping with or
without single phase fault is not very different.

to third parties is forbidden without prior written approval
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

3.4.9.1. N TRANSFER

At first, the maximum transfer capacities were calculated without taking the
contingencies into account. The operation criteria are not taken into account either.
The limit is reached when the system loses stability by voltage collapse, frequency
collapse and/or loss of synchronism.

Table lists the transfer limits between countries for the Base case, at peak load. To
establish these limits, the flow from one country to another was increased
progressively and slowly, to let the system automatically adjust to the variations
(excitation systems of the machines, SVC controllers, automatic tap changers of
transformers,…).

Because the electricity laws have to be respected, the flow is divided between the
different possible paths to reach the load. The table shows the loopflows, i.e. the
flows transiting through other countries via parallel paths.

For instance, when Senegal imports power from Mali, an important part of it, instead
of going to Senegal via the 225 kV OMVS interconnection, flows through the CLSG
and OMVG interconnections. When 54 MW flow via the direct path, 24 MW take
the deviation via CLSG and OMVG interconnections.

Table gives the maximum transfer capacities in N condition for Scenario 2, at peak
load. As a result, the values are lower, because the system is less interconnected.

Figure 7911 and Figure illustrate the limits of stability for the transfer from Ivory
Coast to Burkina Faso, in Scenario 2, at peak load.

The initial situation has a big importance in the results obtained and must be taken
into account when reading the tables. An initial situation with different production
commitment and exchanges on the interconnection would lead to different results.

For instance, when looking at the case concerning the transit from Ivory Coast to
Guinea, the results are negative values for the Base case at peak load. In the initial
situation, Kaleta produces 240 MW so that Guinea exports towards Senegal, The
Gambia, Guinea Bissau, Sierra Leone and Liberia. The initial transit on the line
between Man and Yekepa is null. When the flow is increased from Ivory Coast to
Guinea, this flow progressively changes to reach 97 MW from Man to Yekepa
before the stability is lost. These 97 MW are the maximum transfer capacity for this
scenario. They concern the CLSG interconnection only, without adding the 45 MW
loopflow that passes first through Senegal before going to Guinea.

The table permits also to conclude that the N maximum transfer capacity is always
lower than the thermal capacity of the interconnections. One exception to this rule
goes for the interconnections between Ghana and Togo, where the 161 kV lines
were overloaded before the system lost stability.

to third parties is forbidden without prior written approval
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

| From Country | To Country | From Substation | To Substation | Rated SN MVA | Initial flow MW | Max N MW |  |
| --- | --- | --- | --- | --- | --- | --- | --- |
| Mali | Senegal | Kayes | Matam | 234 | 106 | 160 |  |
| Soma | Kaolack | 250 | 96 | 120 |  |  |  |
| Mali | Burkina Faso | Sikasso | Kodeni | 250 | -26 | 102 |  |
| Ferkessedougou | Kodeni | 327 | -1 | 42 |  |  |  |
| Guinea | Senegal | Boke | Saltinho | 250 | 190 | 245 |  |
| Kayes | Matam | 234 | 106 | 127 |  |  |  |
| Guinea | Ivory Coast | Linsan | Kamakwie | 250 | 40 | 175 |  |
| Sikasso | Ferkessedougou | 250 | -54 | -16 |  |  |  |
| Ivory Coast | Mali | Ferkessedougou | Sikasso | 250 | 56 | 122 |  |
| Matam | Kayes | 234 | -99 | -85 |  |  |  |
| Kodeni | Sikasso | 250 | 26 | 61 |  |  |  |
| Ivory Coast | Guinea | Man | Yekepa | 250 | 0 | 97 |  |
| Boke | Kaleta | 250 | -191 | -146 |  |  |  |
| Ivory Coast | Burkina Faso | Ferkessedougou | Kodeni | 327 | -1 | 26 |  |
| Sikasso | Kodeni | 250 | -26 | 11 |  |  |  |
| Bolgatanga | Kodeni | 250 | 62 | 60 |  |  |  |
| Bolgatanga | Zagtouli | 327 | 46 | 86 |  |  |  |
| Ghana | Riviera | Prestea | 1100 | 36 | 512 |  |  |
|  |  | Abobo | Elubo | 327 | -30 | 269 |  |
| Kodeni | Bolgatanga | 250 | -59 | 34 |  |  |  |
| Zagtouli | Bolgatanga | 327 | -45 | -35 |  |  |  |
|  |  | Prestea | Riviera | 1100 | -36 | 193 |  |
|  | Elubo | Abobo | 327 | 30 | 170 |  |  |
| Bolgatanga | Kodeni | 250 | 62 | 105 |  |  |  |
| Bolgatanga | Zagtouli | 327 | 46 | 48 |  |  |  |
|  |  | Burgina Faso | Bolgatanga | Kodeni | 250 | 62 | 80 |
|  | Bolgatanga | Zagtouli | 327 | 46 | 82 |  |  |
| Ferkessedougou | Kodeni | 327 | -1 | 8 |  |  |  |
|  |  | Kodeni | Sikasso | 250 | 27 | 65 |  |
| Ferkessedougou | Sikasso | 250 | 56 | 106 |  |  |  |
|  |  | Togo/Benin | Volta | Lome | 1100 | 4 | 617 |
| Asiekpe | Lome | 128 | 26 | 212 |  |  |  |
| Afao | Lome | 128 | 24 | 182 |  |  |  |
| Bawku | Dapaong | 182 | -21 | 71 |  |  |  |
|  |  | Malanville | Zabori | 777 | 2 | 19 |  |
| Birin Kebbi | Zabori | 777 | 157 | 195 |  |  |  |
| Ouagadougou | Niamey | 777 | -100 | -68 |  |  |  |
| Birin Kebbi | Dosso | 95 | 57 | 79 |  |  |  |

Table 116 – Base case, peak load– Maximum transfer capacity without contingency

to third parties is forbidden without prior written approval
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

| From Country | To Country | From Substation | To Substation | Rated SN MVA | Initial flow MW | Max N MW |
| --- | --- | --- | --- | --- | --- | --- |
| Mali | Senegal | Kayes | Matam | 234 | 150 | 194 |
| Ivory Coast | Mali | Ferkessedougou | Sikasso | 250 | 35 | 102 |
| Ivory Coast | Guinea | Man | Yekepa | 250 | 119 | 172 |
| Ivory Coast | Burkina Faso | Ferkessedougou | Kodeni | 327 | -5 | 66 |
| Bolgatanga | Zagtouli | 327 | 53 | 101 |  |  |
| Ivory Coast | Ghana | Abobo | Elubo | 327 | -53 | 427 |
| Zagtouli | Bolgatanga | 327 | -52 | 57 |  |  |
| Ghana | Ivory Coast | Elubo | Abobo | 327 | 54 | 394 |
| Bolgatanga | Zagtouli | 327 | 53 | 119 |  |  |
| Ghana | Burkina Faso | Bolgatanga | Zagtouli | 327 | 53 | 113 |
| Ferkessedougou | Kodeni | 327 | -5 | 41 |  |  |
| Ghana | Benin | Volta | Lome | 1100 | -19 | 429 |
| Asiekpe | Lome | 128 | 23 | 152 |  |  |
| Aflao | Lome | 128 | 21 | 138 |  |  |
| Bawku | Dapaong | 182 | -31 | 36 |  |  |
| Nigeria | Benin | Ikeja West | Sakete | 777 | 32 | 493 |
| Nigeria | Niger | Birnin Kebbi | Dosso | 95 | 65 | 146 |

Table 117 – Scenario 2, peak load – Maximum transfer capacity without contingency

to third parties is forbidden without prior written approval
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

| From Country | To Country | From Substation | To Substation | Rated SN MVA | Initial flow MW | Max N MW |
| --- | --- | --- | --- | --- | --- | --- |
| Mali | Senegal | Kayes | Matam | 234 | 58 | 128 |
| Soma | Kaolack | 250 | 10 | 41 |  |  |
| Mali | Burkina Faso | Sikasso | Kodeni | 250 | -29 | 108 |
| Ferkessedougou | Kodeni | 327 | -5 | 42 |  |  |
| Guinea | Senegal | Boke | Saltinho | 250 | 62 | 157 |
| Kayes | Matam | 234 | 58 | 89 |  |  |
| Guinea | Ivory Coast | Linsan | Kamakwie | 250 | -9 | 197 |
| Sikasso | Ferkessedougou | 250 | -46 | 12 |  |  |
| Ivory Coast | Mali | Ferkessedougou | Sikasso | 250 | 47 | 142 |
| Matam | Kayes | 234 | -56 | -30 |  |  |
| Kodeni | Sikasso | 250 | 30 | 84 |  |  |
| Ivory Coast | Guinea | Man | Yekepa | 250 | 38 | 113 |
| Boke | Kaleta | 250 | -62 | -27 |  |  |
| Ivory Coast | Burkina Faso | Ferkessedougou | Kodeni | 327 | -5 | 31 |
| Sikasso | Kodeni | 250 | -29 | 19 |  |  |
| Bolgatanga | Kodeni | 250 | 52 | 51 |  |  |
| Bolgatanga | Zagtouli | 327 | 38 | 103 |  |  |
| Riviera | Prestea | 1100 | 30 | 581 |  |  |
| Ghana | Ghana | Abobo | Elubo | 327 | -31 | 285 |
| Kodeni | Bolgatanga | 250 | -51 | 51 |  |  |
| Zagtouli | Bolgatanga | 327 | -38 | -27 |  |  |
| Prestea | Riviera | 1100 | -30 | 396 |  |  |
| Ghana | Ivory Coast | Elubo | Abobo | 327 | 32 | 258 |
| Bolgatanga | Kodeni | 250 | 52 | 128 |  |  |
| Bolgatanga | Zagtouli | 327 | 38 | 43 |  |  |
| Bolgatanga | Kodeni | 250 | 52 | 80 |  |  |
| Ghana | Burkina Faso | Bolgatanga | Zagtouli | 327 | 38 | 103 |
| Ferkessedougou | Kodeni | 327 | -5 | 12 |  |  |
| Kodeni | Sikasso | 250 | 30 | 91 |  |  |
| Ghana | Mali | Kodeni | Sikasso | 250 | 47 | 121 |
| Ghana | Togo/Benin | Volta | Lome | 1100 | 13 | 629 |
| Asiekpe | Lome | 128 | -5 | 192 |  |  |
| Aflao | Lome | 128 | -5 | 165 |  |  |
| Bawku | Dapaong | 182 | -13 | 76 |  |  |
| Benin | Niger | Malanville | Zabori | 777 | 8 | 45 |
| Birmin Kebbi | Zabori | 777 | 94 | 157 |  |  |
| Ouagadougou | Niamey | 777 | -61 | -4 |  |  |
| Birmin Kebbi | Dosso | 95 | 33 | 76 |  |  |

Table 118 – Base case, off peak load– Maximum transfer capacity without contingency

to third parties is forbidden without prior written approval
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

| From Country | To Country | From Substation | To Substation | Rated SN MVA | Initial flow MW | Max N MW |
| --- | --- | --- | --- | --- | --- | --- |
| Mali | Senegal | Kayes | Matam | 234 | 69 | 150 |
| Ivory Coast | Mali | Ferkessedougou | Sikasso | 250 | 55 | 125 |
| Ivory Coast | Guinea | Man | Yekepa | 250 | 84 | 168 |
| Ivory Coast | Burkina Faso | Ferkessedougou | Kodeni | 327 | 29 | 57 |
| Bolgatanga | Zagtouli | 327 | 77 | 94 |  |  |
| Ivory Coast | Ghana | Abobo | Elubo | 327 | -51 | 394 |
| Zagtouli | Bolgatanga | 327 | -75 | 15 |  |  |
| Ghana | Ivory Coast | Elubo | Abobo | 327 | 52 | 299 |
| Bolgatanga | Zagtouli | 327 | 77 | 125 |  |  |
| Ghana | Burkina Faso | Bolgatanga | Zagtouli | 327 | 77 | 100 |
| Ferkessedougou | Kodeni | 327 | 29 | 47 |  |  |
| Ghana | Benin | Volta | Lome | 1100 | 12 | 621 |
| Asiekpe | Lome | 128 | -11 | 182 |  |  |
| Aflao | Lome | 128 | -11 | 160 |  |  |
| Bawku | Dapaong | 182 | -35 | 58 |  |  |
| Nigeria | Benin | Ikeja West | Sakete | 777 | 156 | 714 |
| Nigeria | Niger | Birnin Kebbi | Dosso | 95 | 64 | 91 |

Table 119 – Scenario 2, off peak load – Maximum transfer capacity without contingency

to third parties is forbidden without prior written approval
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

Figure 7911 – Scenario 2 (peak load) – Maximum transfer capacity from Ivory Coast to
Burkina Faso: active power flows on interconnection lines

Figure 80 – Scenario 2 (peak load) – Maximum transfer capacity from Ivory Coast to Burkina
Faso: voltage profile

to third parties is forbidden without prior written approval
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

3.4.9.2. N-1 TRANSFER

With the application of the N-1 criterion, the WAPP system should be operated in
such situations that the loss of one element of the system will not lead to its
instability. It means the contingencies around the interconnections and on the
interconnections must be supported by the system.

In case of radial system or in case of single interconnection between two countries
(as it is the case now between Senegal and Mali for instance), the issue of maximum
transfer capacity in N-1 condition is limited to two possible scenarios:

1. The contingency concerns an element internal to one of both systems and the
   interconnection remains in service. The stability must be maintained on the
   interconnection.

2. The contingency concerns the interconnection. In this case, the scenario leads to

3. The contingency concerns the interconnection. In this case, the scenario leads to
   the splitting of both systems. The exporting system must be able to reduce its
   power production before reaching over-frequency limits, or to shed production
   units. The importing system must be able to use its spinning reserve to
   compensate the loss of imported power, or it must rely on defense schemes like
   Under Frequency Load Shedding.
   For this kind of systems, i.e. radial systems, it is possible to define a maximum


For this kind of systems, i.e. radial systems, it is possible to define a maximum
transfer capacity, even though the availability of certain means to support the
voltage will have an influence.

In case of meshed networks, like the WAPP existing and future system, the situation
is more complex. At first, the power flows control is more difficult. The flows will
respect the laws of electricity, creating loopflows, as explained and showed in the N
transfer analysis above. Secondly, the point number two described above is not a
possible scenario anymore. Because there are several interconnections between the
countries, an interconnection contingency does not provoke the splitting of the
system in two parts. The flows are redirected instantaneously, according to the
electricity laws. Such flow changes can immediately lead to instability.

An excellent example is Senegal. Presently, Senegal is interconnected only with
Mali via a single 225 kV line. In case of interconnection contingency, both systems
are separated and the scenario is as described in point 2 above. In the future, Senegal
will be interconnected with Mali and with the OMVG countries in such a way that a
loop is created. In case of loss of interconnection between Senegal and Mali, the
power exported from Mali to Senegal will not disappear but will flow by the only
way left: the OMVG interconnection. Such high loopflow through several countries
and thousands of kilometers will reduce the stability of the system.

As a matter of fact, because of the N-1 criterion, it is possible that the maximum
transfer capacity determined for an interconnection feeding a radial system is
reduced once this radial system becomes meshed with the addition of another
interconnection.

to third parties is forbidden without prior written approval
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

3.4.9.2.1. 2015 Base case, peak load

For the Base case at peak load,

Table and Table summarize the maximum transfer calculations. The transfers
between countries are presented with:

• The countries at the origin and destination of the transfer.
The interconnection lines involved. Sometimes, the latter are not directly related

• The interconnection lines involved. Sometimes, the latter are not directly related
to the transfer but are indicated because they experience loopflows.
The thermal rated power of each interconnection line involved.

• The thermal rated power of each interconnection line involved.
The initial active power flow of each interconnection line involved.

• The initial active power flow of each interconnection line involved.
The active power flow of each interconnection involved just before the system

• The active power flow of each interconnection involved just before the system
loses stability in N condition.
The active power flow of each interconnection just before the system loses

• The active power flow of each interconnection just before the system loses
stability in N-1 condition. The worst incident is here considered.
The list of incidents that were taken into account for calculating the maximum

• The list of incidents that were taken into account for calculating the maximum
transfer capacity in N-1 condition. These incidents are limited to those with the
biggest impact on the transfer studied. Colors are attributed to the incidents
according to their severity and their consequences in the scenario:
-Red color for incidents that are not supported by the system in the initial

-Red color for incidents that are not supported by the system in the initial
situation. The system loses stability for that incident, before any power
transfer is increased.
-Orange color for the incident that limits the capacity in N-1 condition. It is the

-Orange color for the incident that limits the capacity in N-1 condition. It is the
most severe of the list for the transfer studied.
A comment on the instability experienced by the system in N-1 condition.

• A comment on the instability experienced by the system in N-1 condition.
Figure and Figure illustrate the system behavior for the transfer increase from Mali

Figure and Figure illustrate the system behavior for the transfer increase from Mali
to Burkina Faso, with contingency on 225 kV line Sikasso-Kodeni.

For the Base case, at peak load, several interconnections losses are not supported by
the system. There are two major problems:

The contingency on the 225 kV line between Kaleta and Boke is illustrated in Figure
and Figure . The loss of the interconnection between Guinea and Senegal provokes a
redirection of the flows to the interconnection between Mali and Senegal. The
system cannot support it and it loses stability with the loss of synchronism between
the units in Senegal on one side and the units in Guinea, Sierra Leone and Liberia on
the other side.

• The North-core project is very important for Niger, where voltage collapse
occurs in Niamey in case of contingency on the line Birnin Kebbi-Malanville-
Niamey, following the flows redistribution.
Despite the foreseen interconnections, Senegal and Niger are the two countries

to third parties is forbidden without prior written approval
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

3.4.9.2.2. 2015 Scenario 2, peak load

For Scenario 2, Table summarizes the maximum transfer calculations. Because
there are fewer interconnections, the network is more radial and less meshed. Only
Ghana, Ivory Coast, Burkina Faso, Togo and Benin are part of this meshed network
and maximum transfer capacities in N-1 condition could be calculated for the
interconnections between these countries. The other countries are in radial parts of
the network.

Figure illustrates the transfer limit for exchanges from Ghana to Ivory Coast. The
most severe incident for such exchange is the tripping of the 225 kV line between
Abobo and Elubo. When the stability limit is reached, it causes the loss of
synchronism of Burkina Faso first, followed by a loss of synchronism between the
block Ghana/Togo/Benin/Niger/Nigeria on one side and the other block Ivory
Coast/Liberia/Sierra Leone/Guinea/Mali/Senegal on the other side. Figure
illustrates the transfer limit for exchanges from Ghana to Burkina Faso. The most
severe incident for such exchange is the tripping of the 225 kV line between
Bolgatanga and Zagtouli. When the stability limit is reached, it causes the loss of
synchronism first between Guinea/Sierra Leone on one side, Liberia on another side
and all the other countries on a third side. Right after, it provokes the loss of
synchronism of Burkina Faso.

to third parties is forbidden without prior written approval
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

| From Country | To Country | From Substation | To Substation | Rated SN MVA | Initial flow MW | Max N MW | Max N-1 MW | Incident list | Comment |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| Mali | Senegal | Kayes | Matam | 234 | 106 | 160 |  | line Kayes-Matam line Kaleta-Boke Sendou unit | Loss of synchronism and voltage collapse Initial flows are too important |
| Soma | Kaolack | 250 | 96 | 120 |  |  |  |  |  |
| Mali | Burkina Faso | Sikasso | Kodeni | 250 | -26 | 102 | 69 | line Sikasso-Kodeni line Ferkesedougou-Kodeni Manasema unit | loss of synchronism in Burkina Faso |
| Ferkesedougou | Kodeni | 327 | -1 | 42 | 33 |  |  |  |  |
| Guinea | Senegal | Boke | Saltinho | 250 | 190 | 245 |  | line Kaletta-Boke line Kayes-Matam Sendou unit | Loss of synchronism and voltage collapse Initial flows are too important |
| Kayes | Matam | 234 | 106 | 127 |  |  |  |  |  |
| Guinea | Ivory Coast | Linsan | Kamakwie | 250 | 40 | 175 |  | line Kamakwie-Boke line Kalета-Linsan line Linsan-Kamakwie line Kayes-Matam 2NewCC unit Buyo unit | Loss of synchronism and voltage collapse Initial flows are too important |
| Sikasso | Ferkesedougou | 250 | -54 | -16 |  |  |  |  |  |
| Ferkesedougou | Sikasso | 250 | 56 | 122 |  |  |  |  |  |
| Matam | Kayes | 234 | -99 | -85 |  |  |  |  |  |
| Kodeni | Sikasso | 250 | 26 | 61 |  |  |  |  |  |
| Ivory Coast | Mali | Ferkesedougou | Sikasso | 250 | 56 | 122 |  | line Ferkesedougou-Sikasso line Kayes-Matam line Kodeni-Sikasso line Ferkesedougou-Kodeni line Manantail-Tata Manantail unit Vicabo unit | Loss of synchronism and voltage collapse Initial flows are too important |
| Matam | Kayes | 234 | -99 | -85 |  |  |  |  |  |
| Kodeni | Sikasso | 250 | 26 | 61 |  |  |  |  |  |
|  |  |  |  |  |  |  |  |  |  |
|  |  |  |  |  |  |  |  |  |  |
| Ivory Coast | Guinea | Man | Yekepa | 250 | 0 | 97 |  | line Man-Yekepa line Kaleta-Ferkesedougou-Sikasso line Linsan-Kaleta line Kaletta-Boke line Linsan-Kamakwie Kaleta unit Maneah unit | Loss of synchronism and voltage collapse Initial flows are too important |
| Boke | Kaleta | 250 | -191 | -146 |  |  |  |  |  |
|  |  |  |  |  |  |  |  |  |  |
|  |  |  |  |  |  |  |  |  |  |
|  |  |  |  |  |  |  |  |  |  |
| Ivory Coast | Burkina Faso | Ferkesedougou | Kodeni | 327 | -1 | 26 | 7 | line Ferkesedougou-Kodeni line Sikasso-Kodeni line Ferkesedougou-Sikasso line Bolgatanga-Kodeni line Bolgatanga-Zagtouli line Rviera-Prestea Manasema unit |  |
| Sikasso | Kodeni | 250 | -26 | 11 | -15 |  |  |  |  |
| Bolgatanga | Kodeni | 250 | 62 | 60 | 62 |  |  |  |  |
| Bolgatanga | Zagtouli | 327 | 46 | 86 | 58 |  |  |  |  |
|  |  |  |  |  |  |  |  |  |  |
| Ivory Coast | Ghana | Rwiera | Prestea | 1100 | 36 | 512 | 329 | line Ferkesedougou-Sikasso line Ferkesedougou-Kodeni line Ferkesedougou-Kodeni line Rviera-Prestea Manasema unit | loss of synchronism between Ivory Coast and Ghana |
| Abobo | Elubo | 327 | -30 | 269 | 149 |  |  |  |  |

Table 120 – Base case (peak load) - Maximum transfer capacities in N-1 condition (1/2)

to third parties is forbidden without prior written approval
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

| From Country | To Country | From Substation | To Substation | Rated SN MVA | Initial flow MW | Max N MW | Max N-1 MW | Incident list | Comment |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| Ghana | Ivory Coast | Prestea | Riviera | 1100 | -36 | 193 | 177 | line Riviera - Prestea | Low voltages and loss of synchronism in Burkina Faso |
| Elubo | Abobo | 327 | 30 | 170 | 161 | line Abobo - Elubo | Elubo-Abobo flow close to thermal capacity |  |  |
| Bolgatanga | Kodeni | 250 | 62 | 105 | 104 | line Bolgatanga - Zaqtouli |  |  |  |
| Bolgatanga | Zaqtouli | 327 | 46 | 48 | 49 | line Bolgatanga - Kodeni 2NewCC unit |  |  |  |
| Ghana | Burkina Faso | Bolgatanga | Kodeni | 250 | 62 | 80 | 65 | line Bolgatanga - Zaqtouli | loss of synchronism in Burkina Faso |
| Bolgatanga | Zaqtouli | 327 | 46 | 82 | 67 | line Bolgatanga - Kodeni |  |  |  |
| Ferkessedougou | Kodeni | 327 | -1 | 8 | 5 | Manasema unit |  |  |  |
| Mali | KodeniFerkessedougou | Sikasso | 250 | 27 | 65 | 63 | line Bolgatanga - Kodeniline Ferkessedougou - Sikassoline Ferkessedougou - Kodeniline Manantali - Tkitaline Sikasso - KodeniManantal unitVicabo unit | loss of synchronism in Burkina Faso |  |
| Ghana | Togo/Benin | Volta | Lome | 1100 | 4 | 617 | 419 | line Volta - Lome | Voltage collapse in Ghana (node 1391DCEM) |
| Aseikpe | Lome | 128 | 26 | 212 | 154 | line Asiekpe - Lome |  |  |  |
| Afaao | Lome | 128 | 24 | 182 | 139 | line Afiao - Lome |  |  |  |
| Bawku | Dapaong | 182 | -21 | 71 | 42 | line Bawku - Dapaong Maria Gleta unit (1GT+1/2ST) |  |  |  |
| Benin | Niger | Malanville | Zabori | 777 | 2 | 19 |  | line Malanville-Zaboru-Namey-Birmi | Voltage collapse at Namey |
| Birnin Kebbi | Zabori | 777 | 157 | 195 |  | line Ouagadougou-Namey | Initial flows are too important |  |  |
| Ouagadougou | Namey | 777 | -100 | -68 |  | line Birnin Kebbi-Dosso-Nigereol unit |  |  |  |
| Birnin Kebbi | DOSso | 95 | 57 | 79 |  | line Ouagadougou-Namey | Voltage collapse at Namey |  |  |
| Nigeria | Burkina Faso | Namey | Ouagadougou | 777 | 102 | 136 |  | line Namey-Zaboru-Namey-Birmi | Initial flows are too important |
| Bolgatanga | Zaqtouli | 327 | 46 | 63 |  | line Bolgatanga - Zaqtouli |  |  |  |
| Bolgatanga | Kodeni | 250 | 62 | 69 |  | line Bolgatanga - Kodeni Manasema unit |  |  |  |
| Benin | Ikeja West | Sakete | 777 | 49 | 566 |  | line Ikeja West-Sakete | Voltage collapse at Namey |  |
| Nigeria | Benin | Zabori | Malanville | 777 | -2 | 20 |  | line Malanville-Zaboru-Namey-Birmi | Initial flows are too important |
| Zaqtouli | Bolgatanga | 327 | -45 | 21 |  | Saoa2CC1 unit |  |  |  |
| Birnin Kebbi | Zabori | 777 | 157 | 230 |  | line Malanville-Zaboru-Namey-Birmi | Voltage collapse at Namey |  |  |

Table 121 – Base case (peak load) - Maximum transfer capacities in N-1 condition (2/2)

to third parties is forbidden without prior written approval
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

Figure 81 – Base case (peak load) – Maximum capacity transfer in N-1 condition from Mali to
Burkina Faso: contingency on line Sikasso-Kodeni 225 kV (upper chart: transfer on line
Sikasso-Kodeni 225 kV, lower chart: transfer on line Ferkessedougou-Kodeni)(red curves:
unstable case, blue curves: stable case)

Figure 82 – Base case (peak load) – Maximum capacity transfer in N-1 condition from Mali to
Burkina Faso: contingency on line Sikasso-Kodeni 225 kV (upper chart: unstable case, lower
chart: stable case)

to third parties is forbidden without prior written approval
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

Figure 83 – Base case (peak load) – Contingency on 225 kV line between Kaleta and Boke
(upper chart: active power flows on line Kaleta-Boke and Kayes-Matam (Senegal-Mali
border), lower chart: machine speed at Kaleta in Guinea)

Figure 84 – Base case (peak load) – Contingency on 225 kV line between Kaleta and Boke:
machines angular positions (loss of synchronism between Guinea and Senegal)

to third parties is forbidden without prior written approval
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

| From Country | To Country | From Substation | To Substation | Rated SN MVA | Initial flow MW | Max N MW | Max N-1 MW | Incident list | Comment |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| Ivory Coast | Burkina Faso | Ferkessedougou Bolgatanga | Kodeni Zagtouli | 327 | -5 | 66 | 21 | line Ferkessedougou - Kodeni line Ferkessedougou - Sikasso line Bolgatanga - Zagtouli line Abobo-Elubo Manasema unit | Loss of synchronism in Burkina Faso |
|  |  |  |  |  |  |  |  |  |  |
|  |  |  |  |  |  |  |  |  |  |
|  |  |  |  |  |  |  |  |  |  |
| Ivory Coast | Ghana | Abobo Zagtouli | Elubo Bolgatanga | 327 | -53 | 427 | 65 | line Ferkessedougou - Sikasso line Ferkessedougou - Kodeni line Bolgatanga - Zagtouli line Abobo-Elubo Aksombo unit Saso2CC1 unit | Loss of synchronism between Ivory Coast and Ghana/Burkina Faso |
|  |  |  |  |  |  |  |  |  |  |
|  |  |  |  |  |  |  |  |  |  |
|  |  |  |  |  |  |  |  |  |  |
| Ghana | Ivory Coast | Elubo Bolgatanga | Abobo Zagtouli | 327 | 54 | 394 | 85 | line Ferkessedougou - Sikasso line Ferkessedougou - Kodeni line Bolgatanga - Zagtouli line Abobo-Elubo 2NewCC unit | Loss of synchronism in Burkina Faso |
|  |  |  |  |  |  |  |  |  |  |
|  |  |  |  |  |  |  |  |  |  |
|  |  |  |  |  |  |  |  |  |  |
| Ghana | Burkina Faso | Bolgatanga Ferkessedougou Kodeni | Zagtouli | 250 | 53 | 113 | 74 | line Bolgatanga - Zagtouli line Ferkessedougou - Kodeni line Abobo-Elubo Manasema unit | Loss of synchronism between Guinea, Burkina Faso and Ghana/Ivory Coast |
|  |  |  |  |  |  |  |  |  |  |
|  |  |  |  |  |  |  |  |  |  |
|  |  |  |  |  |  |  |  |  |  |
| Ghana | Benin | Volta Asiekpe Aflao Bawku | Lome Lome Lome Dapaong | 1100 128 128 182 | -19 23 21 -31 | 429 152 138 36 | 389 141 129 31 | line Volta - Lome line Asiekpe - Lome line Aflao - Lome line Bawku - Dapaong Maria Gleta unit (1GT+1/2ST) | Low voltages in Togo |
|  |  |  |  |  |  |  |  |  |  |
|  |  |  |  |  |  |  |  |  |  |
|  |  |  |  |  |  |  |  |  |  |
|  |  |  |  |  |  |  |  |  |  |

Table 122 – Scenario 2 (peak load) - Maximum transfer capacities in N-1 condition

to third parties is forbidden without prior written approval
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

Figure 85 – Scenario 2 (peak load) - Maximum capacity transfer in N-1 condition from Ghana
to Ivory Coast: contingency on line Abobo-Elubo 225 kV (upper chart: transfer on line
Bolgatanga-Zagtouli: red curve=unstable, blue curve = stable. lower chart: machines angular
positions in the different countries for the unstable case)

Figure 86 – Scenario 2 (peak load) - Maximum capacity transfer in N-1 condition from Ghana
to Burkina Faso: contingency on line Bolgatanga-Zagtouli 225 kV (upper chart: transfer on
line Ferkessedougou-Kodeni: red curve=unstable, blue curve = stable. lower chart: Machines
angle in the different countries for the unstable case)

to third parties is forbidden without prior written approval
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

3.4.9.2.3. 2015 Base case, off peak load

Table and Table provide the maximum transfer capacities for the Base case, in off peak
load condition.

As can be seen, two incidents provoked the instability of the system and prevented the
calculation of N-1 maximum transfer capacities:

• The contingency on the wind farm in Senegal. It was showed in section 3.4.7, and in
Figure and Figure that it provokes the instability of Senegal.
The contingency of the line between Kaleta and Linsan. The flows redistribution, with

• The contingency of the line between Kaleta and Linsan. The flows redistribution, with
all the power from Kaleta going to Senegal, provokes voltage drops and loss of
synchronism in Guinea and Sierra Leone. The system response is illustrated in Figure
.

3.4.9.2.4. 2015 Scenario 2, off peak load

Table presents the maximum transfer capacities for Scenario 2, in off peak load
condition.

The incident on line Bolgatanga – Zagtouli is not supported by the system. The flow
redistribution provokes voltage collapse in Burkina Faso and north of Ivory Coast, as
depicted in Figure 8812.

3.4.9.3. CONCLUSIONS FOR THE MAXIMUM TRANSFER CAPACITIES

For meshed systems, it is impossible to attribute one single value to each line as the
maximum transfer capacity in N-1 condition. As explained above, it depends on many
elements, and above all the initial situation. This analysis is willing to provide an idea of
the transfer level it is possible to reach between countries considering the expected
scenario of exchanges. It also shows the most constraining incident for each transfer.

In large meshed interconnected systems, as the WAPP will be, maximum transfer
capacities are calculated daily, on basis of information collected from each country. It is
recommended to initiate such system and prepare to collect such information in order to
be ready calculating the dynamic stability limits of the system when the interconnections
will be commissioned. In the end, the goal is to calculate regularly the maximum transfer
capacities for the network loads, productions and exchanges foreseen. Then the
calculations would permit to identify the loopflows and the expected flows on the
interconnections could be compared with the maximum transfer capacities calculated.

to third parties is forbidden without prior written approval
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

| From Country | To Country | From Substation | To Substation | Rated SN MVA | Initial flow MW | Max N MW | Max N-1 MW | Incident list | Comment |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| Mali | Seneqal | Kayes | Matam | 234 | 58 | 128 |  | line Kayes-Matamline Kaleta-BokeWend ram | voltage collapse and loss of synchronism in Senegal, The Gambia and Guinea Bissau |  |
| Soma | Kaolack | 250 | 10 | 41 |  |  |  |  |  |  |
| Burkina Faso | Kodeni | 250 | -29 | 108 | 96 | line Skasso - Kodeniline Ferkessedougou - Kodeni Manasema unit | voltage collapse in Burkina Faso |  |  |  |
| Mali | Burkina Faso | Skasso | Kodeni | 250 | -29 | 108 | 96 |  |  |  |
| Ferkessedougou | Kodeni | 327 | -5 | 42 | 40 | voltage collapse and loss of synchronism in Senegal, The Gambia and Guinea Bissau |  |  |  |  |
| Guinea | Seneqal | Boke | Sakinho | 250 | 62 | 157 | 74 | line Kayes - Bokeline Kayes - MatamVire dum | voltage collapse and loss of synchronism in Senegal, The Gambia and Guinea Bissau |  |
| Kayes | Matam | 234 | 58 | 89 | 60 |  |  |  |  |  |
| Guinea | Ivory Coast | Linsan | Kamakwie | 250 | -9 | 197 |  | line Kaletta - Bokeline Kaletta - Linsanline Linsan - Kamakwieline Kayes - Matam2NewCC unitBuyo unit | loss of synchronism in Guinea |  |
| Skasso | Ferkessedougou | 250 | -46 | 12 |  |  |  |  |  |  |
| Mali | Ferkessedougou | Skasso | 250 | 47 | 142 | 137 | line Ferkessedougou - Skasso |  |  |  |
| Matam | Kayes | 234 | -56 | -30 | 13 |  |  |  |  |  |
| Ivory Coast | Mali | Ferkessedougou | Kodeni | Skasso | 250 | 30 | 84 | 81 | line Ferkessedougou - Kodeniline Manantal - TkitaManantal unitVicabo unit | low voltages in Mali |
| ManBoke | Yekepa | 250 | 38 | 113 |  |  |  |  |  |  |
| Kaleta | 250 | -62 | -27 |  |  |  |  |  |  |  |
|  |  |  |  |  |  |  |  |  |  |  |
| Ivory Coast | Guinea | ManBoke | Yekepa | 250 | 38 | 113 |  | line Man - YekepaLine Kayes - Matamline Ferkessedougou - Skassoline Linsan - Kaletaline Kalета - Bokeline Linsan - KamakwieKaleta unitManeah unit | loss of synchronism in Guinea |  |
| ManBoke | Yekepa | 250 | 38 | 113 |  |  |  |  |  |  |
| Kaleta | 250 | -62 | -27 |  |  |  |  |  |  |  |
|  |  |  |  |  |  |  |  |  |  |  |
| Ivory Coast | Burkina Faso | Ferkessedougou | Kodeni | 327 | -5 | 31 | 22 | line Ferkessedougou - Kodeniline Skasso - Kodeniline Ferkessedougou - Skassoline Bolgatanga - Kodeniline Bolgatanga - Kodeniline Bolgatanga - Zagtouliline Rivera - PresteaManasema unit | loss of synchronism and low voltages in Burkina Faso |  |
| Skasso | Kodeni | 250 | -29 | 19 | 6 |  |  |  |  |  |
| Bolgatanga | Kodeni | 250 | 52 | 51 | 52 |  |  |  |  |  |
| Bolgatanga | Zagtouli | 327 | 38 | 103 | 87 | line Bolgatanga - Zagtouliline Rivera - PresteaManasema unit | loss of synchronism between Ghana and Ivory Coast |  |  |  |

Table 123 - Base case (off peak load) - Maximum transfer capacities in N-1 condition (1/2)

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

| case number | From Country | To Country | From Substation | To Substation | Rated SN MVA | Initial flow MW | Max N MW | Max N-1 MW | Incident list | Comment |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 19 | Ghana | Ivory Coast | Prestea | Rwiera | 1100 | -30 | 396 | 275 | line Riviera - Prestea | voltage collapse in Burkina Faso |
| Elubo | Abobo | 327 | 32 | 258 | 198 | line Abobo - Elubo |  |  |  |  |
| Bolgatanga | Kodeni | 250 | 52 | 128 | 109 | line Bolgatanga - Zaqtouli |  |  |  |  |
| Bolgatanga | Zaqtouli | 327 | 38 | 43 | 42 | line Bolgatanga - KodeniZNewCC unit |  |  |  |  |
| 20 | Ghana | Burkina Faso | Bolgatanga | Kodeni | 250 | 52 | 80 | 65 | line Bolgatanga - Zaqtouli | voltage collapse in Burkina Faso |
| Bolgatanga | Zaqtouli | 327 | 38 | 103 | 83 | line Bolgatanga - Kodeni |  |  |  |  |
| Ferkessedougou | Kodeni | 327 | -5 | 12 | 8 | line Manasema unit |  |  |  |  |
| 21 | Ghana | Mali | Kodeni | Sikasso | 250 | 30 | 91 | 82 | line Bolgatanga - Kodeni | voltage collapse in Burkina Faso |
| Ferkessedougou | Sikasso | 250 | 47 | 121 | 109 | line Bolgatanga - Zaqtouli |  |  |  |  |
| Volta | Lome | 1100 | 13 | 629 | 401 | line Bolgatanga - Zaqtouli |  |  |  |  |
| Aseikepe | Lome | 128 | -5 | 192 | 116 | line Ferkessedougou - Sikasso |  |  |  |  |
| Afaao | Lome | 128 | -5 | 165 | 108 | line Ferkessedougou - Kodeni |  |  |  |  |
| 23 | Ghana | Togo/Benin | Volta | Lome | 1100 | 13 | 629 | 401 | line Volta - Lome | loss of synchronism between Ghana and Togo |
| Aseikepe | Lome | 128 | -5 | 192 | 116 | line Aseikepe - Lome |  |  |  |  |
| Afaao | Lome | 128 | -5 | 165 | 108 | line Afaao - Lome |  |  |  |  |
| Bawku | Dapaong | 182 | -13 | 76 | 44 | line Bawku - DapaongMaria Gleta unit (1GT+1/2ST) |  |  |  |  |
| 26 | Benin | Niger | Malanville | Zabori | 777 | 8 | 45 | 15 | line Malanville-Zabori-Namey-Birmin | low voltages in Niger |
| Birnin Kebbi | Zabori | 777 | 94 | 157 | 114 | line Ouagadougou-Namey |  |  |  |  |
| Ouagadougou | Namey | 777 | -61 | -4 | -47 | line Birnin Kebbi - Dosso |  |  |  |  |
| Birnin Kebbi | DOSso | 95 | 33 | 76 | 42 | Niereol unit |  |  |  |  |
| 27 | Nigeria | Burkina Faso | Namey | Ouagadougou | 777 | 61 | 130 | 81 | line Ouagadougou-Namey | voltage collapse in Burkina Faso |
| Bolgatanga | Zaqtouli | 327 | 38 | 68 | 47 | line Malanville-Zabori-Namey-Birmin |  |  |  |  |
| Bolgatanga | Kodeni | 250 | 52 | 67 | 56 | line Bolgatanga - Zaqtouli |  |  |  |  |
| Bolgatanga | Kodeni | 250 | 52 | 67 | 56 | line Bolgatanga - KodeniManasema unit |  |  |  |  |

Table 124 - Base case (off peak load) - Maximum transfer capacities in N-1 condition (2/2)

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

| From Country | To Country | From Substation | To Substation | Rated SN MVA | Initial flow MW | Max N MW | Max N-1 MW | Incident list | Comment |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| Ivory Coast | Burkina Faso | Ferkessedougou Bolgatanga | Kodeni Zagtouli | 327 | 29 | 57 |  | line Ferkessedougou - Kodeni line Ferkessedougou - Sikasso line Bolgatanga - Zagtouli line Abobo-Elubo Komsilga1 unit | voltage collapse in Burkina Faso |
|  |  |  |  |  |  |  |  |  |  |
|  |  |  |  |  |  |  |  |  |  |
|  |  |  |  |  |  |  |  |  |  |
| Ivory Coast | Ghana | Abobo Zagtouli | Elubo Bolgatanga | 327 | -51 | 394 |  | line Ferkessedougou - Sikasso line Ferkessedougou - Kodeni line Bolgatanga - Zagtouli line Abobo-Elubo Aksombo unit Saso2CC1 unit | voltage collapse in Burkina Faso |
|  |  |  |  |  |  |  |  |  |  |
|  |  |  |  |  |  |  |  |  |  |
|  |  |  |  |  |  |  |  |  |  |
|  |  |  |  |  |  |  |  |  |  |
|  |  |  |  |  |  |  |  |  |  |
| Ghana | Ivory Coast | Elubo Bolgatanga | Abobo Zagtouli | 327 | 52 | 299 |  | line Ferkessedougou - Sikasso line Ferkessedougou - Kodeni line Bolgatanga - Zagtouli line Abobo-Elubo 2NewCC unit | voltage collapse in Burkina Faso |
|  |  |  |  |  |  |  |  |  |  |
|  |  |  |  |  |  |  |  |  |  |
|  |  |  |  |  |  |  |  |  |  |
| Ghana | Burkina Faso | Bolgatanga Ferkessedougou | Zagtouli Kodeni | 250 | 77 | 100 |  | line Bolgatanga - Zagtouli line Ferkessedougou - Kodeni line Abobo-Elubo Komsilga1 unit | voltage collapse in Burkina Faso |
|  |  |  |  |  |  |  |  |  |  |
|  |  |  |  |  |  |  |  |  |  |
| Ghana | Benin | Volta Asiekpe Aflao Bawku | Lome Lome Lome Dapaong | 1100 128 128 128 | 12 -11 -11 -11 | 621 182 160 58 | 418 115 107 26 | line Volta - Lome line Asiekpe - Lome line Aflao - Lome line Bawku - Dapaong Maria Gleta unit (1GT+1/2ST) | low voltages in Ghana and Togo |
|  |  |  |  |  |  |  |  |  |  |
|  |  |  |  |  |  |  |  |  |  |
|  |  |  |  |  |  |  |  |  |  |
|  |  |  |  |  |  |  |  |  |  |

approval
to third parties is forbidden without prior written
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

Figure 87 – Base case (off peak load) – Contingency on line Kaleta – Linsan (upper chart:
voltages in Senegal, Guinea and Sierra Leone. lower chart: machine angular position in
Senegal)

Figure 8812 – Scenario 2 (off peak load) – Contingency on line Bolgatanga – Ouagadougou
(voltage collapse in Burkina Faso and North of Ivory Coast)

to third parties is forbidden without prior written approval
ny duplication or transmission
document is the property of Tractebel Engineering S.A. A
This

* * *

3.5. Operation of the system and control centers

While the previous sections examined the static and dynamic stability of the systems
from a planning point of view, this section treats the stability of the systems from an
operation point of view.

Parts of the WAPP system are already interconnected and already apply a set of rules to
operate together. The operation of the interconnected systems is managed by the control
centers, according to national and regional rules. The regional rules are described in the
“Operation Manual for WAPP interconnected system” and are implemented
progressively.

Nevertheless, these rules are not always respected. The best example is the frequency
control and the spinning reserve. It seems that, neither in the block composed by Ghana-
Ivory Coast-Burkina Faso-Togo-Benin, nor in the block Nigeria-Niger-Benin, there is a
sufficient spinning reserve to cover any unit contingency without shedding load or
experiencing a black out. In Nigeria, the frequency largely varies and blackouts occur
several times a year. The consequence is that, though physically interconnected, these
blocks are presently operated separately by opening lines in Benin.

As first and main recommendation, this section encourages the application of the
“Operation Manual for WAPP interconnected system”. The most important
recommendations are already described in the manual and will not be repeated. This
section is willing to complete and/or amend this manual. It is therefore organized
according to the manual structure.

Finally, some operation issues should be controlled at a higher level than those controlled
by the control centers. It could be a future role to be played by the WAPP, and
particularly the ICC. These issues will be stressed here below.

3.5.1. Policy 1: Load frequency control

The most important recommendation concerning the load frequency control is the strict
respect of the spinning reserves levels attributed to each country. The non respect of this
rules by one member puts all the other members in danger of facing at least load
shedding, at worst a black out. It also provokes uncontrolled frequency variations,
leading to uneconomic operation such as the example of the unsynchronized operation of
the block Ivory Coast-Burkina Faso-Ghana-Togo-Benin and the block Nigeria-Niger-
Benin.
A first step towards the good respect of the spinning reserve rules is to relax the level

A first step towards the good respect of the spinning reserve rules is to relax the level
required. The WAPP operation manual mentions the simultaneous contingency of the
two largest units as the sizing incident (220 MW of Egbin ST in Nigeria and 170 MW of
Akosombo unit in Ghana). It is recommended to take advantage of the opportunity to
reduce the spinning reserve thanks to the interconnections. The probability of a
simultaneous contingency on the two largest units of the system is very low. Keeping
such an amount of spinning reserve for an incident with low probability is not
economically justified; it increases the operation costs to support an event that is unlikely
to happen. It is recommended to cover only the contingency on the largest unit, which is
presently to loss of one GT in Kwale CC in Nigeria with the consequent impact on the
power output of the associated steam turbine (total of 267.8 MW).

to third parties is forbidden without prior written approval
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

On the other hand, the members should be intransigent on the respect of the levels
attributed. The WAPP and the ICC should monitor the production levels of the units and
check these levels are respected.

After respecting the agreed amount of spinning reserve and spreading it in the system, it
is important to ensure the frequency regulation. It is the role of the primary and
secondary controls. These controls are of utmost importance and are already described in
the WAPP operation manual.

And in addition to the WAPP operation manual, it is recommended to release a technical
note describing the requirements in terms of voltage and frequency control for each new
unit to be connected to the network. Such note should be approved by all country and
included in their respective grid codes.

3.5.2. Policy 2: Interchange scheduling and accounting between
control areas

Policy 2 addresses the issue of maximum transfer capacities and this section will describe
with more details the procedure that should be applied to calculate the TTC (Total
Transfer Capacity) and NTC (Net Transfer Capacity).

As already explained in the section calculating the maximum transfer capacities here
above, the results of the TTC calculations will depend on three parameters:

• The system situation studied (peak load, off peak load,…)
The contingencies the system must be able to support (N-1, N-2, single-phase short-

• The contingencies the system must be able to support (N-1, N-2, single-phase shortcircuits, three-phase short circuits,…)
The criteria applied to check the system operation and determine, after contingency,

• The criteria applied to check the system operation and determine, after contingency,
whether it is acceptable.
It is recommended to apply the following parameters:

• The applied criteria to judge the final situation are those used for the normal operation
of the system (levels of overloads tolerated on lines and transformers, acceptable
voltages ranges,…)
These parameters are to be agreed by the countries and the control centers. After that, it

These parameters are to be agreed by the countries and the control centers. After that, it
will be possible to apply an automatic procedure for calculating the transfer capacities.

to third parties is forbidden without prior written approval
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

This procedure implies the cooperation of all countries and all control centers. Since the
WAPP and the ICC are responsible for assessing and publishing the TTC and NTC, it is
proposed that the ICC carries out the automatic day ahead calculations of TTC and NTC.

All countries and control centers should be responsible for providing, one day in
advance, all information regarding load, generation and transmission system for the next
day. This information should be provided in one predefined format corresponding to a
power system calculation software, and delivered to the ICC. The same day, the ICC
should carry out the calculations and publish the results on the WAPP‟s website.

When all “day ahead” information is gathered, it should be assembled by the ICC to form
one single load flow representing the whole interconnected system.

At this stage, a static representation of the system is available. To this representation, the
dynamic data of the system should be added for performing the dynamic simulations.

Dynamic simulations are necessary because, due to the long distances of the
interconnections, the system is more likely to reach the dynamic stability limits before
experiencing static limitations like the thermal rating of the equipments. This has been
shown in the simulations of this study.

It is therefore important to have at disposal a dynamic model of the interconnected
system. Such model should be built once and kept up to date. It does not depend on the
situation studied, so that every day, the static representation will be different but the
dynamic model used will be unique (except for the changes due to system development).

All countries and control centers are responsible for providing all the dynamic
information concerning their systems, and for keeping such information up to date with
the latest system developments. The quality of the model is of utmost importance since it
will have an impact on the TTC results.

With the static and dynamic model of the system, the contingencies will be simulated and
the criteria will be applied to judge whether the situation is acceptable. Initially, the
situation should be acceptable since it represents the expected operation of the system.
From this situation, the flows on the lines should be increased and the contingencies
should be simulated to determine the transfer limit.

3.5.3. Policy 3: Operational security

The policy 3 of the Operation Manual of the WAPP interconnected system could be
completed with the following points:

-should be performed dynamically. It is therefore necessary to have a dynamic
model at disposal. For each neighboring zone, the model could limit itself to the
zone concerned with an equivalent model representing the neighboring areas. A
complete dynamic model of the system should be available and centralized by the
ICC.

• Regular on-line simulations should be performed to assess the security of the system.
Such calculations:

-should include simulations of contingencies on the interconnections with the
neighboring zones, and of the most important elements inside the neighboring
zones.
-should be performed dynamically. It is therefore necessary to have a dynamic

-could be carried out at least once a day at the beginning, and every 15 minutes
when the whole system and procedure are automatic.
-should include simulations of contingencies on the interconnections with the

to third parties is forbidden without prior written approval
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

• The protections settings must have the same tuning on both sides of the
interconnections. International blackouts have already occurred because the system
operators assumed it was like that, though it was not.

3.5.4. Policy 5: Emergency procedures

The policy 5 of the Operation Manual of the WAPP interconnected system should be
amended with the following points:

• UFLS should be harmonized between all countries, with thresholds from 49 Hz to 48
Hz. A frequency limit should be agreed for keeping the system interconnected. For
instance, starting from 48.5 Hz, it could be more interesting to trip the
interconnections and limit the problem to the country where it happened instead of
letting it propagate to the whole system. It is also important to leave a frequency
margin to the other controllers to recover the system to an acceptable state. The note
in appendix provides more information on the harmonization and tuning of UFLS in
interconnected systems.
All units should remain connected between 47.5 Hz and 52.5 Hz, to be coherent with

• All units should remain connected between 47.5 Hz and 52.5 Hz, to be coherent with
the UFLS proposed. Such requirement should be made public in the national gridcode
of each country.
Though voltage management is to be controlled locally, it is also a regional issue

• Though voltage management is to be controlled locally, it is also a regional issue
because voltage problems can lead to losses of synchronism and/or voltage collapses
that will propagate to the interconnected systems. Consequently, it is recommended to
install Under Voltage Load Shedding (UVLS) in the networks.

to third parties is forbidden without prior written approval
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

3.6. Conclusions and recommendations

Static and dynamic studies were carried out for different scenarios in order to analyze the
transmission network performances and stability. This section summarizes the study and
its results, and concludes the analysis with the recommendations and the impact on the
results of the economic study.

3.6.1. Model construction and scenarios investigated

Model construction

The transmission network performances and stability analysis was performed first for
year 2015, at peak and off peak load conditions. For this year, an important work was
furnished to build the simulation model with the limited information collected. Several
assumptions were done to reinforce the national grids. It was supposed each country will
undertake the necessary reinforcements inside its national network to face the load
growth and the consequent power flows in its network. For the dynamic model, the
information received was modeled but a lot of data were missing. As a consequence, data
based on experience and good practices were used to complete the model.

In a second stage, the 2020 and 2025 peak load situations were investigated statically.

Scenarios definition

Two different scenarios were investigated for 2015:

• A first scenario, referred as the Base case, including all future network elements
expected for 2015. The peak load forecasted, the new generation units and new
transmission projects as listed in the inception report were used for building this
scenario. Elements expected for after 2015 were not included in the model, except for
the North-core interconnection and the OMVG interconnection. These exceptions
were made in order to study a situation where all countries are interconnected and
these two projects are of particular importance for Senegal, The Gambia, Guinea
Bissau and Niger.
• A second scenario, referred as Scenario 2, being a variant of the Base case. In this

• North-core interconnection is not in service. Niger is consequently interconnected
only with Nigeria in 132 kV.
• Ghana-Burkina Faso-Mali interconnection is not in service (Bolgatanga-Kodeni-

• A second scenario, referred as Scenario 2, being a variant of the Base case. In this
variant, several network elements were removed. The goal of such scenario is to
analyze the stability of the system for a realistic intermediate stage between the actual
situation of the WAPP system and the expected Base case scenario. The situation
examined is interesting for its weaknesses due to the limited number of commissioned
interconnections:

• Ghana-Burkina Faso-Mali interconnection is not in service (Bolgatanga-Kodeni-
Sikasso).
Ghana-Burkina Faso interconnection is limited to its 225 kV part from Bolgatanga to

• Ghana-Burkina Faso interconnection is limited to its 225 kV part from Bolgatanga to
Ouagadougou and is not supported by the 330 kV north-south link in Ghana. The
latter is not in service.

to third parties is forbidden without prior written approval
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

• The interconnection between Ghana and Ivory Coast is limited to the 225 kV between
Abobo and Elubo. The 330 kV link between Riviera and Prestea is not in service.
As a result, in Scenario 2, the WAPP system is a long line of interconnected countries

As a result, in Scenario 2, the WAPP system is a long line of interconnected countries
from Niger to Senegal, with an antenna for the CLSG interconnection and with the
interconnection of Burkina Faso to Ivory Coast and Ghana.

For 2020 and 2025, the new transmission and production projects and the international
exchanges recommended by the economic study were integrated.

3.6.2. Conclusions of static studies

Operation optimization and reactive compensation

Static studies were first carried out. The system operation was optimized to respect all
operation criteria (voltage ranges and overloads) and maximize the reactive margins on
the generator units. When operation criteria could not be respected, reactive
compensation was installed to reach an acceptable steady-state operation.

As a general conclusion, the power factor of the load in 2015 was assumed to be 0.85
everywhere in the network, and it is recommended to install capacitor banks to increase
this power factor and reduce the reactive transits, particularly in Nigeria but also in
Ghana, Ivory Coast, Togo, Benin and Mali. A target value of 0.9 is recommended for the
power factor in general and it is even recommended to reach a power factor of 1 in the
main load centers (big cities and industrial areas).

The network being composed of long interconnection lines, it clearly comes out of the
study that capacitor banks should be installed at low voltage levels to improve the power
factor and reduce the reactive power flows, and that reactor banks should be installed at
high voltage levels to absorb the reactive power produced by the long and low loaded
interconnection lines. Finally, a good coupling between the high voltage lines and the
reactances absorbing the reactive power they produce is mandatory to avoid large over or
under-voltages in case of contingencies.

Security analysis

The security analysis simulated all lines, transformers and units contingencies.

• The voltage management with few areas at risk: the north of Togo and Benin, parts of
Mali (particularly Segou substation), Senegal and Burkina Faso. It is recommended to
install additional voltage control means, like capacitor/reactor banks or SVC, to
control adequately the voltages in these sensitive areas. It is also recommended to
keep a minimum number of generation units running in the importing countries to
support the voltage.
• The reinforcements needed to evacuate properly the power from the new projects.

As a general conclusion, there are three main problems:

• The long loops formed by the interconnections. Contingencies on these loops do not
comply with the N-1 criterion. Their contingencies often provoke instability due to
the consequent flows redistribution.

to third parties is forbidden without prior written approval
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

Short-circuit study

The short-circuit study revealed risks in Nigeria (in the south), Ghana (Tema area) and
Ivory Coast (Abidjan area), due to the important generation projects foreseen in these
zones.

By lack of information, assumptions were done for the breaker capacities according to
the voltage levels. These breaker capacities should be verified to make sure the shortcircuit currents calculated are below. Otherwise, it is recommended to install breakers
with higher breaking capacities. The levels to be reached are indicated in section 3.4.4.

3.6.3. Conclusions of dynamic studies

Small signal stability

The dynamic studies detected stability issues of primordial importance that are here
highlighted.

The conclusions of the small signal stability are among the most important of this study.

The small signal stability was performed for both scenarios, calculating the eigenvalues
to detect the least damped oscillation modes. Several modes were detected which are all
related to inter-area oscillations. The least damped ones are between:

• The block Ghana/Ivory Coast and the block Senegal/Guinea,
Mali and Senegal,

• Mali and Senegal,

• The block Senegal/Guinea and Nigeria,
Burkina Faso and Ivory Coast,

• Burkina Faso and Ivory Coast,
The block Ghana/Ivory Coast/Togo/Benin and the block Guinea/Sierra Leone.

• The block Ghana/Ivory Coast/Togo/Benin and the block Guinea/Sierra Leone.
The time domain simulations in the study also confirmed these oscillations modes and

The time domain simulations in the study also confirmed these oscillations modes and
concluded that they strongly reduce the stability margins (transient stability margins,
maximum transfer capacities,…). To damp these oscillations and get rid of the stability
limits they impose on the system, it is strongly recommended to:

• Install PSS on all new large future units to be installed in the system.
Check if PSS do not already exist on the biggest machines of every country and, if

• Check if PSS do not already exist on the biggest machines of every country and, if
not, install one.
• Stress the importance of inter-area oscillations analysis in detailed feasibility studies

not, install one.
• Stress the importance of inter-area oscillations analysis in detailed feasibility studies
of future interconnections.

• Install Wide Area Monitoring Systems (WAMS) at different places in the network to
detect and observe the inter-area oscillations. Moreover, it would be very useful to
confirm they are correctly damped after PSS installations.
Transient stability

Transient stability

to third parties is forbidden without prior written approval
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

As a conclusion, the installation of PSS, as recommended in the small signal stability
conclusions, will remove the risk of seeing one single unit lose synchronism in case of
three phase fault cleared in base time. Losses of synchronism will still be possible, but
they will concern parts of the network and not single units.

Units contingencies

Units contingencies were simulated dynamically. The goal was to check the operation
criteria in case of contingency.

For the Base case, all units contingency are supported, except the loss of the coal power
unit of Sendou, in Senegal. This contingency provokes an increase of the imported power
on the interconnections and the maximum transfer capacity is reached, causing the loss of
synchronism and the voltage collapse of Senegal.

For Scenario 2, since there are fewer interconnections, the voltage control is more
difficult. After units contingencies, voltage collapses or voltages out of the +10/-10%
range allowed after contingencies were detected in Senegal, Mali, Burkina Faso, Niger,
Guinea, Liberia and Sierra Leone.

Spinning reserve, primary frequency control and WAPP operation manual

The spinning reserve was sized to the largest unit contingency in the system: one gas
turbine and half the power of the steam turbine in the combined cycle of Okpai (Kwale)
in Nigeria. This represents 267.8 MW.

The spinning reserve was distributed among the countries according to a rule based on
their national load level in comparison with the global load of the WAPP system.

With such level of spinning reserve spread sufficiently on the running units, it was
observed that the frequency drop can be limited to values above 49.3 Hz, which is
satisfactory. The lowest frequency reached will depend on the amount of active power
lost, but also on the repartition of the spinning reserve on the running units. It is
recommended to spread this reserve on as many units as possible.

In case a country is interconnected to the rest of the system via a single line, it is
important that this country keeps enough spinning reserve to face the loss of the
interconnection, with the related imports. Another solution to face such incident is to rely
on special protection schemes and defense schemes.

Moreover, the analysis of the WAPP operation manual revealed that:

Finally, UFLS should be installed in all countries, and should be harmonized for
countries where it already exists. A proposal for harmonization has already been done for
Ghana, Ivory Coast, Burkina Faso, Togo and Benin, in the frame of Ghana‟s
Transmission Masterplan Study. This study was performed recently and the note with the
recommendations for the harmonization of the UFLs can be found in appendix.

• The first UFLS thresholds are set at 49.5 and 49.2 Hz.
All units must remain connected between 48.5 Hz and 51 Hz.

to third parties is forbidden without prior written approval
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

Use of the three phase fault as a sizing incident

The simulation of metallic three phase faults on lines showed the incapacity of the
system to support the transient and recover to a stable state.

Once again, many problems are worsened by the poor damping of the inter-area
oscillations and installing PSS would increase the stability of the system facing three
phase faults.

Nevertheless, problems remain even after installation of PSS. The three phase fault is a
too severe incident for the system stability.

It is consequently recommended to use the single phase fault as sizing incident and rely
on protection and defense schemes in case three-phase faults would occur. The latter has
a low probability of occurrence and in large systems with long distances as the WAPP, it
is usually not supported.

Maximum transfer capacities: OMVG and North-core critical contingencies

Dynamic simulations of lines contingencies revealed the critical stability issues of the
North-core and OMVG interconnections:

• With the installation of the OMVG network, a loop is created, formed by the OMVG,
CLSG and OMVS interconnections. In case of contingency of one element of this
loop, the initial flows are redirected on the remaining part of the loop. The long
distances and the importance of the redirected flows are such that the system is unable
to support them. It will provoke voltage collapses and losses of synchronism. This is
critical for Senegal, which expects to increase its importation with the OMVG
interconnection.
The North-core interconnection is of utmost importance for Niger and will also permit

• The North-core interconnection is of utmost importance for Niger and will also permit
to send power from Nigeria to Burkina Faso. In this study, the part of the
interconnection between Birnin Kebbi (Nigeria) and Niamey (Niger) is assumed to be
a single line with tapping to Malanville (Benin). In case of contingency, the three
sides of the line are tripped and the stability in Niger is highly compromised.
The problems detected on these interconnections are related to the high flows expected.

The problems detected on these interconnections are related to the high flows expected.
Reducing these flows could be a stable solution but would be unaffordable for the
economics of the system. It is consequently recommended to:

• Reinforce these interconnections. Different possible solutions exist:

-planning new interconnections (from Manantali in Mali to Tambacounda in
Senegal, linking the OMVG and OMVS grids, for instance to reinforce the loop
OMVS-OMVG-CLSG),
-changing the foreseen topology of the interconnections (the feasibility study of the

-doubling the circuits,
-planning new interconnections (from Manantali in Mali to Tambacounda in

-Installing SVC. In these cases, Niamey in Niger and Tobene in Senegal are good
locations. The SVC would improve the operation but will not solve the problems
of loop instability.
In the meantime, before such reinforcements are operational, operate the system

to third parties is forbidden without prior written approval
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

Maximum transfer capacities: Determination of the stability limit

For meshed interconnected systems, the maximum transfer capacities are established for
defined scenarios. Depending on the scenarios characteristics (production plan, load
level, exchanges forecast,…) the results will be different.

The study examined the maximum transfer capacities for the two scenarios considered. It
showed the stability of the system in N condition for the exchanges levels foreseen. It
also showed the instability of the system in N-1 condition for the loop created by
OMVG, CLSG and OMVS interconnections, and for the line between Nigeria, Benin and
Niger in the North-core interconnection. For what concerns the other interconnections,
the system is stable in N-1 condition while reaching the exchanges levels foreseen.

Because the maximum transfer capacity depends on too many parameters, it is never
recommended, in meshed systems, to limit the transfer to a fixed and determined value.
The usual practice consists in carrying out daily dynamic simulations to reproduce the
expected network state for the next day, and calculate the maximum transfer capacities
for that scenario.

It requires the installation of a communication system to exchange information between
countries. With such information, it is possible to simulate the network state expected for
the next day, check the impact of loopflows and verify the maximum transfer capacity
limits are respected.

It is recommended to initiate such communication system and be ready for doing these
daily simulations when the OMVG and North-core interconnections will be
commissioned.

Dynamic simulation model

Given the importance of the dynamic simulations results presented above, it is necessary
to emphasize the limits of the dynamic model used in this study.

As already explained, a lot of assumptions were done to complete the missing
information. The experience of the Consultant and international good practices were
applied to this task.

Though the quality of the dynamic model is sufficient to perform this study and does not
put into question the validity of its results, it is recommended to undertake a dedicated
data collection to improve this dynamic model.

The goal of this improvement is to reach a sufficient quality to perform other studies
such as:

• The tuning of the protection schemes and defense schemes
The daily calculation of maximum transfer capacities

To this purpose the data collected on dynamics of the generators must be improved, in
terms of dynamic parameters and transfer functions of controllers, especially the biggest
ones. But also the load model, and its share of rotating loads, must be improved thanks to
dedicated data collection and/or recordings of the system behavior. The share of rotating
load has a great impact on the voltage recovery in the system after a fault.

• The daily calculation of maximum transfer capacities
To this purpose the data collected on dynamics of the generators must be improved, in

to third parties is forbidden without prior written approval
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

3.6.4. Critical conclusions

The set of interconnection projects that have been considered constitute the minimum
regional transmission equipment that is necessary to for the long term development of the
WAPP countries. The projects taken into account are priority investments but still they
are not sufficient. Indeed, even after implementing all these projects, some weaknesses
remain on the system. The weak points are the following:

• The presence of inter-zonal oscillations in the future interconnected system, reducing
the stability. Their future presence is very likely, whatever the interconnections
planned in the system. Such oscillations appear in large system, with long
interconnection lines. Given the geography, and the willingness of the WAPP
countries to interconnect, any investment list would lead to intermediate network
situation where inter-zonal oscillations would appear. Nevertheless, this project
should improve in the future, with the progressive reinforcements of the
interconnections.
The incapacity to cover the N-1 criterion on the OMVG, CLSG, OMVS and North-

• The incapacity to cover the N-1 criterion on the OMVG, CLSG, OMVS and Northcore interconnections. Unless two or more interconnections are built at the same time,
there will be an intermediate development stage of the system where configurations
like the OMVG, CLSG and OMVS loop will appear.
As a conclusion, it is recommended to:

As a conclusion, it is recommended to:

• Install PSS to improve the small signal stability of the system.
Add transmission lines to evacuate the power from the hydro projects in Guinea,

• Add transmission lines to evacuate the power from the hydro projects in Guinea,
Sierra Leone, Liberia and Ivory Coast to the other countries. The following
interconnections are in first positions: Linsan-Manantali, Manantanli-Kodialani-
Sikasso, Fomi-Boundiali, OMVG and CLSG.
Reinforce the interconnections with Senegal to make the OMVG-OMVS-CLSG loop

• Reinforce the interconnections with Senegal to make the OMVG-OMVS-CLSG loop
stable in N-1 condition for the expected exchanges level. Different options are
possible:
-Doubling the circuits

-Doubling the circuits
-Adding new interconnections

-Adding new interconnections (Kayes-Tambacounda, Linsan-Fomi-Kodialani,
Linsan-Manantali and Fomi-Boundiali are good examples)
Reinforce the interconnections with Niger to make the North-core interconnection

• Reinforce the interconnections with Niger to make the North-core interconnection
stable in N-1 condition with the expected flow levels. Different options are possible:
-Doubling the circuits

-Doubling the circuits
-Reviewing the foreseen topology (commissioning of an intermediate substation at

-Reviewing the foreseen topology (commissioning of an intermediate substation at
Zabori or separation of the line Birnin Kebbi-Niamey with tapping to Malanville
into two different lines from Malanville to Niamey and from Malanville to Birnin
Kebbi, for instance).
Rely on defense schemes for operating the system beyond the limits imposed by the

• Rely on defense schemes for operating the system beyond the limits imposed by the
N-1 criterion before these reinforcements are commissioned.
Harmonize the UFLS schemes of the different countries.

• Install additional means to keep the voltages in admitted ranges inside national grids
(north Togo and Benin, Burkina Faso, Mali, Senegal). SVC in Niger and Senegal
could improve the stable operation of the huge loops formed by the OMVG-OMVS-
CLSG and the North-core-Coastal backbone interconnections.
Improve the dynamic simulation model of the WAPP countries.

• Harmonize the UFLS schemes of the different countries.
Compensate the load to reach a minimum power factor of 0.9. A power factor of 1

• Compensate the load to reach a minimum power factor of 0.9. A power factor of 1
should be reached in the main urban centers.
Install additional means to keep the voltages in admitted ranges inside national grids

• Improve the dynamic simulation model of the WAPP countries.
Implement a communication system to exchange data between countries.

• Implement a communication system to exchange data between countries.

to third parties is forbidden without prior written approval
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

• Prepare to perform daily calculations of maximum transfer capacities according to the
network state expected for the next day.

3.6.5. Impact on the results of the economic study

The technical study examined the recommendations of the economic study and
investigated the operation problems the new production projects and the associated
power flows will provoke.

Besides all the recommendations above-mentioned, the main goal is to determine the
impact of technical issues on the priority investment list, i.e. on the conclusions of the
master plan.

The critical issues detected that will influence the priority projects list are the following:

• The evacuation of the hydro power from Guinea, Sierra Leone, Liberia and Ivory
Coast to the other countries. The most economic development plan for the WAPP
system is to invest in hydro projects in these countries and export the power to the
other countries, replacing the expensive thermal plants. This implies new
interconnection lines and reinforcements of existing interconnection lines to support
the power flows. It is very important to link the production projects with transmission
projects to avoid developing the transmission projects without having any power to
export.
• The stability of the long interconnection loops and the compliance with the N-1

• The stability of the long interconnection loops and the compliance with the N-1
criterion. The example of the CLSG-OMVG-OMVS loop has been quoted above.
Such loops are very difficult to operate in a stable way, while keeping the high power
flows levels expected and respecting the N-1 criterion. They are prone to lead the
system to instability and should be avoided and/or shortened. The interconnection
between Guinea and Mali, passing through Fomi, should shorten the loop but it is not
sufficient to ensure a stable operation.
The voltage support in the importing countries. The importing countries tend to shut

• The voltage support in the importing countries. The importing countries tend to shut
down their generation for importing power. Doing this, there are less units in service
and the voltage support is consequently weakened. The stability in these countries is
usually the factor determining the maximum power transfer capacity on the
interconnections. In this case, the use of SVC is a good solution. Building new
production plants in these countries is another solution.
Based on these issues, the following influence can be noted on the projects to be
supported at regional level.

Based on these issues, the following influence can be noted on the projects to be
supported at regional level.

The study showed that the creation of this line increases the flows on the lines from
Manantali to Bamako in Mali and Kodeni (Bobo Diolasso) and Zagtouli (Ouagadougou)
in Burkina Faso. At least the line from Manantali to Kodialani should be reinforced.

The interconnection line between Linsan and Manantali, with the development of
the hydro power plants of Boureya and Koukoutamba, and reinforcements of the
lines towards Bamako in Mali

to third parties is forbidden without prior written approval
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

The issue of the connection to Linsan or Labe was raised. It is recommended to connect
it to Linsan. With Kaléta and Sambangalou, there is enough production to feed Sénégal,
The Gambia and Guinea Bissau. The power of these plants will then be transited to the
CLSG countries, to Mali, Burkina Faso and Ghana. It is consequently better to connect to
Linsan instead of Labe to shorten the distances these flows will travel.

The coal power plant of Salkadamna with interconnection of River and Center-East
areas in Niger, and interconnection to Nigeria

The North-core interconnection between Benin, Niger and Nigeria is a critical
interconnection for the stability in Niger. The reinforcement of the area can be achieved
by developing the project of Salkadamna, with interconnection of the River and Center-
East areas in Niger.

The project could be developed in two phases, with priority for the River area
connection, to be realized as soon as possible, especially if the hydro projects of
Kandadji and Dyodyodonga are not implemented. Nevertheless, the interconnection with
the zone of Kano and Katsina in north Nigeria would be very useful to supply this area of
north Nigeria. This zone should be fed also by the 760 kV foreseen in Nigeria. This
second phase is less urgent and could be realized after 2020.

The 225 kV line between Kayes and Tambacounda with the project of Gouina

The project of Gouina is decided and it is expected to be accompanied with a 225 kV line
from Kayes to Tambacounda. This line is critical to improve the stability of the
interconnections and imports towards Senegal. It is important, on a technical point of
view, to ensure that this line will be built with the project of Gouina.

The production projects in Senegal: coal power plant of Sendou and renewables

The large imports of power in Senegal represent a threat for the stability of this area
located at the extreme West of the WAPP system. Increasing the production in Senegal is
necessary to follow the national load but it also means reducing its imports and
improving the stability. Therefore, the coal plant project of Sendou and the renewable
opportunities (wind energy) should be supported, and realized as soon as possible.

Renewable projects in importing countries: Burkina Faso, Mali and Niger

These three countries have important renewable opportunities (wind or solar). The latter
would permit to reduce the imports, while in the same time improving the stability and
providing voltage support sources.

They could be realized as soon as possible.

This line is useful to export the hydro power from Guinea to Burkina Faso. It also
reduces the size of the loop composed of the CLSG-OMVG-OMVS interconnections.

The interconnection line between Fomi and Boundiali

to third parties is forbidden without prior written approval
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

Nevertheless, the stability improvements only are not sufficient to justify the investment.
Since the goal is to export hydro power, this project should be realized in addition with
hydro projects in the area. Most of the projects with a regional character are not located
in this area. And even the realization of hydro project in the area of Linsan could see
their power first evacuated via the 225 kV line from Linsan to Fomi before going to
Boundiali.

The reinforcement of the western part of the OMVG interconnection

This interconnection should be reinforced because it is of utmost importance for The
Gambia and Guinea Bissau, it permits to evacuate the hydro power from Guinea, and it
improves the stability of the loop OMVG-OMVS-CLSG.

To couple it with a hydro production project, Poudadlé, Amarya or Balassa are good
candidates

The reinforcement of the CLSG interconnection and/or the interconnection line
between Monrovia (Liberia) and San Pedro (Ivory Coast)

On one side, when the flows from Ivory Coast to Liberia will reverse with the
development of the hydro project in Guinea, Sierra Leone and Liberia, the CLSG
interconnection will have to be reinforced. On the other side, the hydro project of Tiboto
is located exactly on the border between Liberia and Ivory Coast and its realization
supposes the interconnection from Monrovia to San Pedro, which is parallel to the CLSG
interconnection.

The best proposal would be to reinforce the CLSG interconnection between Monrovia
and Man, while developing the Tiboto project with connection to Ivory Coast only. This
proposal is justified by the distance ratio between Tiboto/San Pedro and
Tiboto/Monrovia, and by the expected flows direction from Ivory Coast to Ghana and
Burkina Faso. This proposal is not incompatible with the fact that Liberia would have its
share of the energy of Tiboto, since it is located on the border and this share is just a
matter of flows measurements.

Nevertheless, if this proposal was unacceptable for Liberia, developing both the
interconnection Monrovia-San Pedro and doubling the CLSG between Monrovia and
Man is not necessary on the medium term, but could become necessary on the long term
if more hydro projects were to be developed in Sierra Leone or Liberia.

The median backbone project and the hydro plant of Zungeru (Nigeria)

This reinforcement does not seem to be a priority according to the technical study. Togo
is expected to import in the coming years and the economic study proposed to build a
combined-cycle in the country. This will reduce the imports and the need of
reinforcements of this interconnection.

The hydro project of Zungeru could be fully absorbed by Niger and Nigeria, without
need of new evacuation lines to the north of Togo and Benin. Nevertheless, the median
backbone interconnection is important to reduce the loop formed by the North-core and
the Coastal backbone interconnections.

The coastal backbone reinforcement

to third parties is forbidden without prior written approval
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

The reinforcement of the north-south axis in Benin

Neither the load in the north of Benin nor the export from Benin to Niger seem important
enough to label this reinforcement as high priority according to the technical study
results.

From a stability point of view, this reinforcement reduces the instability of the loop
formed by the North-core and the Coastal backbone interconnections.

The reinforcements in northern Ivory Coast, in Mali and in Burkina Faso

In case an important number of projects are developed in Guinea, Sierra Leone, Liberia
and Ivory Coast, with purpose of exporting towards Mali, Burkina Faso and Ghana, other
high voltage lines should be reinforced:

• 225 kV line Manantali-Kodialani (Mali)
225 kV line Kodialani-Sikasso-Kodeni (Mali-Burkina Faso)

• 225 kV line Kodialani-Sikasso-Kodeni (Mali-Burkina Faso)
225 kV line Soubre-Man-Laboa-Boundiali-Ferkessedougou (Ivory Coast)

• 225 kV line Soubre-Man-Laboa-Boundiali-Ferkessedougou (Ivory Coast)
225 kV line Ferkessedougou-Kodeni (Ivory Coast-Burkina Faso)

• 225 kV line Ferkessedougou-Kodeni (Ivory Coast-Burkina Faso)
225 kV line Soubre-Taabo (Ivory Coast)

• 225 kV line Soubre-Taabo (Ivory Coast)
225 kV line Kodeni-Zagtouli (Burkina Faso)

• 225 kV line Kodeni-Zagtouli (Burkina Faso)
Here again, these reinforcements projects are difficult to implement in association with

Here again, these reinforcements projects are difficult to implement in association with
the development of a particular hydro project. It is very important to develop them only
if the flows were to increase.

Given the uncertainties on the capability of developing so many projects in Guinea,
Sierra Leone and Liberia, and the fact that some hydro projects are usually associated
with mines projects rather than exports to neighboring countries, these reinforcement
projects could be considered on the long term only.

to third parties is forbidden without prior written approval
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

# 4\. APPENDIX: STATIC STUDIES: SHORT-CIRCUIT ANALYSIS: RESULTS

to third parties is forbidden without prior written approval

ny duplication or transmission

This document is the property of Tractebel Engineering S.A. A

MP-WAPP/4NT/221291/002/00 October 2011 250/273

* * *

| Node Name | Voltage kV | Breaker rating kA | Country Name | 3ph SC current Base case kA | 3ph SC current BC all units kA | 3ph SC current Scenario 2 kA | 3ph SC current SC2 all units kA |
| --- | --- | --- | --- | --- | --- | --- | --- |
| AERO008 | 90 | 25 | SE | 7.11 | 9.88 | 8.10 | 9.84 |
| BELAIR08 | 90 | 25 | SE | 9.72 | 15.84 | 11.44 | 15.73 |
| CAPEB08 | 90 | 25 | SE | 12.2 | 23.87 | 16.63 | 23.59 |
| DAGANA03 | 225 | 31.5 | SE | 2.24 | 2.36 | 2.17 | 2.21 |
| DAGIA\_01 | 90 | 25 | SE | 8.57 | 12.96 | 10.32 | 12.87 |
| FICT2\_08 | 90 | 25 | SE | 6 | 6.91 | 6.30 | 6.75 |
| HANN \_08 | 90 | 25 | SE | 10.51 | 17.72 | 12.81 | 17.58 |
| KAHO1\_08 | 225 | 31.5 | SE | 3.48 | 3.69 | 2.30 | 2.40 |
| KAOLAC08 | 90 | 25 | SE | 4.61 | 4.78 | 3.81 | 2.60 |
| KOUNU003 | 225 | 31.5 | SE | 2.29 | 2.66 | 2.41 | 3.92 |
| KOUNOU08 | 90 | 25 | SE | 11.22 | 17.29 | 13.47 | 17.03 |
| MATAM\_03 | 225 | 31.5 | SE | 1.94 | 1.90 | 1.85 | 1.82 |
| MATAM\_08 | 90 | 25 | SE | 3.34 | 3.50 | 3.50 | 3.52 |
| MBAO \_08 | 90 | 25 | SE | 10.07 | 16.83 | 12.79 | 16.70 |
| MBOUR\_08 | 90 | 25 | SE | 3.32 | 3.55 | 3.33 | 3.45 |
| MECKHE08 | 90 | 25 | SE | 2.43 | 2.50 | 2.36 | 2.40 |
| PATTED08 | 90 | 25 | SE | 9.72 | 15.63 | 11.72 | 15.52 |
| SANAL\_03 | 225 | 31.5 | SE | 2.68 | 2.94 | 2.44 | 2.52 |
| IBBA\_08 | 90 | 25 | SE | 5.39 | 6.88 | 6.05 | 6.86 |
| SOCOCI08 | 90 | 25 | SE | 12.07 | 18.16 | 14.48 | 17.82 |
| SOMETA08 | 90 | 25 | SE | 3.39 | 3.66 | 3.49 | 3.62 |
| TAIBA\_08 | 90 | 25 | SE | 3.85 | 4.01 | 3.66 | 3.75 |
| TAMBAC03 | 225 | 31.5 | SE | 1.48 | 1.59 | 1.28 | 1.38 |
| TANAF\_03 | 225 | 31.5 | SE | 1.67 | 2.88 |  |  |
| TOBEENE0 | 90 | 25 | SE | 4.84 | 5.27 | 4.86 | 5.08 |
| TOBEENE08 | 90 | 25 | SE | 3.08 | 3.31 | 2.70 | 2.81 |
| TOBUA\_03 | 225 | 31.5 | SE | 5.92 | 6.30 | 5.48 | 5.68 |

Table 126 – 3ph short-circuit current levels for 2015 (1/4)

to third parties is forbidden without prior written approval
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

| Node Name | Voltage kV | Breaker rating kA | Country Name | 3ph SC current Base case kA | 2ph SC current BC all units kA | 3ph SC current Scenario 2 kA | 3ph SC current SC2 all units kA |
| --- | --- | --- | --- | --- | --- | --- | --- |
| 2050BOUA | 225 | 31.5 | CI | 2.99 | 3.10 | 2.84 | 2.92 |
| 2051BOUA | 90 | 25 | CI | 3.16 | 3.19 | 3.11 | 3.13 |
| 2060FERK | 225 | 31.5 | CI | 3.07 | 3.61 | 2.38 | 2.57 |
| 2061FERK | 90 | 25 | CI | 3.03 | 3.20 | 2.71 | 2.80 |
| 2070SQUB | 225 | 31.5 | CI | 3.82 | 4.08 | 3.79 | 4.07 |
| 2070SUBR | 90 | 25 | CI | 3.6 | 3.68 | 3.59 | 3.67 |
| 2080S-PE | 225 | 31.5 | CI | 1.87 | 1.93 | 1.87 | 1.92 |
| 2090PEDR | 90 | 25 | CI | 3.49 | 3.57 | 3.48 | 3.55 |
| 2090BUYO | 225 | 31.5 | CI | 3.47 | 3.93 | 3.42 | 3.86 |
| 2091BUYO | 90 | 25 | CI | 3.55 | 5.00 | 3.53 | 4.97 |
| 20PAYE90 | 90 | 25 | CI | 1.98 | 2.00 | 1.98 | 1.99 |
| 2100MAN | 225 | 31.5 | CI | 2.21 | 2.40 | 2.12 | 2.29 |
| 2101MAN- | 90 | 25 | CI | 2.54 | 2.63 | 2.49 | 2.56 |
| 2110LABO | 225 | 31.5 | CI | 1.69 | 1.78 | 1.60 | 1.66 |
| 2111LABO | 90 | 25 | CI | 2.11 | 2.16 | 2.04 | 2.08 |
| 2120AGBO | 90 | 25 | CI | 3.16 | 3.21 | 3.16 | 3.19 |
| 2130DABO | 90 | 25 | CI | 2.15 | 2.17 | 2.15 | 2.17 |
| 2150PLAT | 90 | 25 | CI | 2.72 | 3.20 | 2.73 | 3.14 |
| 2160BAN | 90 | 25 | CI | 22.45 | 26.82 | 21.73 | 25.08 |
| 2170AYAM | 90 | 25 | CI | 22.33 | 26.66 | 21.61 | 24.90 |
| 2180AYAM | 90 | 25 | CI | 2.06 | 3.47 | 2.05 | 3.46 |
| 2190ABRO | 90 | 25 | CI | 2.06 | 3.51 | 2.06 | 3.50 |
| 2200BASS | 90 | 25 | CI | 2.82 | 3.35 | 2.81 | 3.34 |
| 2200BASS | 90 | 25 | CI | 4.27 | 4.74 | 4.23 | 4.69 |
| 2210RRV1 | 225 | 31.5 | CI | 19.54 | 16.84 | 11.14 | 12.81 |
| 2210BRAS | 90 | 25 | CI | 19.51 | 22.59 | 18.43 | 20.84 |

Table 127 – 3ph short-circuit current levels for 2015 (2/4)

to third parties is forbidden without prior written approval
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

| Node Name | Voltage kV | Breaker rating kA | Country Name | 3ph SC current Base case kA | 3ph SC current BC all units kA | 3ph SC current Scenario 2 kA | 3ph SC current SC2 all units kA |
| --- | --- | --- | --- | --- | --- | --- | --- |
| 1109PRES | 225 | 31.5 | GH | 7.1 | 7.57 | 5.82 | 5.99 |
| 1110DUNK | 161 | 31.5 | GH | 6.66 | 6.93 | 5.95 | 6.16 |
| 1120OBUA | 161 | 31.5 | GH | 7.47 | 7.81 | 6.56 | 6.82 |
| 1130KUMA | 161 | 31.5 | GH | 9.25 | 9.85 | 6.63 | 6.98 |
| 1138T261 | 161 | 31.5 | GH | 4.54 | 4.67 | 4.18 | 4.31 |
| 1138T262 | 161 | 31.5 | GH | 7.75 | 8.17 | 5.91 | 6.16 |
| 1139K2BS | 161 | 31.5 | GH | 9.48 | 10.07 | 5.80 | 6.04 |
| 1140NKAW | 161 | 31.5 | GH | 7.86 | 8.20 | 6.84 | 7.07 |
| 1150TAFO | 161 | 31.5 | GH | 9.56 | 10.14 | 9.21 | 9.59 |
| 1160AKWA | 161 | 31.5 | GH | 4.5 | 4.60 | 4.34 | 4.42 |
| 1170KPON | 161 | 31.5 | GH | 16.51 | 19.89 | 16.79 | 18.79 |
| 1180KONG | 161 | 31.5 | GH | 15.32 | 15.27 | 4.43 | 19.68 |
| 1190KPON | 161 | 31.5 | GH | 11.79 | 13.07 | 11.92 | 12.68 |
| 1200ASAW | 161 | 31.5 | GH | 4.55 | 4.71 | 4.18 | 4.35 |
| 1210JUAB | 161 | 31.5 | GH | 3.22 | 3.30 | 3.02 | 3.12 |
| 1210JON-OB | 161 | 31.5 | GH | 8.01 | 8.41 | 6.95 | 7.25 |
| 1220ASIE | 161 | 31.5 | GH | 5.55 | 5.90 | 5.60 | 5.83 |
| 1252KPAN | 161 | 31.5 | GH | 2.45 | 2.51 | 2.46 | 2.50 |
| 1252TECH | 161 | 31.5 | GH | 6.54 | 7.10 | 5.39 | 5.90 |
| 1270SUNY | 161 | 31.5 | GH | 5.24 | 5.52 | 4.67 | 4.98 |
| 1278MIM | 161 | 31.5 | GH | 3.15 | 3.23 | 2.94 | 3.05 |
| 1280TAMA | 161 | 31.5 | GH | 2.48 | 2.55 | 2.05 | 2.14 |
| 1290BOLG | 161 | 31.5 | GH | 4.87 | 5.23 | 2.35 | 2.48 |
| 1295IBLG | 225 | 31.5 | GH | 3.11 | 3.43 | 1.58 | 1.68 |
| 1300BDOGO | 161 | 31.5 | GH | 14.21 | 12.21 | 8.45 | 8.76 |

Table 128 – 3ph short-circuit current levels for 2015 (3/4)

to third parties is forbidden without prior written approval
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

| Node Name | Voltage kV | Breaker rating kA | Country Name | 3ph SC current Base case kA | 3ph SC current BC all units kA | 3ph SC current Scenario 2 kA | 3ph SC current SC2 all units kA |
| --- | --- | --- | --- | --- | --- | --- | --- |
| DIFFA\_02 | 330 | 31.5 | NR | 2.29 | 2.31 | 2.29 | 2.31 |
| DOSSO02 | 330 | 31.5 | NR | 2.87 | 3.42 |  |  |
| DOSSO\_02 | 132 | 25 | NR | 3.13 | 2.64 | 4.16 | 3.66 |
| FRONT\_06 | 132 | 25 | NR | 3.02 | 3.22 | 3.21 | 3.30 |
| MACAD06 | 132 | 25 | NR | 2.74 | 2.88 | 2.74 | 2.80 |
| MARAD06 | 132 | 25 | NR | 1.18 | 1.30 | 1.18 | 1.30 |
| NIAM20C06 | 132 | 25 | NR | 0.73 | 0.60 | 0.98 | 0.80 |
| NIAM2\_02 | 132 | 25 | NR | 4.96 | 8.43 | 4.13 | 5.32 |
| NIAMRD02 | 132 | 31.5 | NR | 2.51 | 3.41 |  |  |
| NIAMRD06 | 132 | 25 | NR | 5.06 | 8.27 |  |  |
| NIAMRD02 | 132 | 25 | NR | 3.22 | 3.72 |  |  |
| ZINDER06 | 132 | 25 | NR | 2.6 | 2.75 | 2.60 | 2.75 |
| ABUJA\_01 | 760 | 31.5 | NI | 6.59 | 6.78 | 6.57 | 6.73 |
| AFAM\_02 | 330 | 31.5 | NI | 23.89 | 37.14 | 24.41 | 34.99 |
| AYEDE02 | 330 | 31.5 | NI | 10.84 | 11.06 | 10.65 | 10.84 |
| AJAKOUI02 | 760 | 31.5 | NI | 9.24 | 9.69 | 9.20 | 9.58 |
| AJAKOUI02 | 760 | 31.5 | NI | 21.92 | 21.78 | 20.94 | 21.34 |
| AJA\_02 | 330 | 31.5 | NI | 26.01 | 29.88 | 25.72 | 28.39 |
| 330 | 31.5 | NI | 21.32 | 22.60 | 20.28 | 21.25 |  |
| 330 | 31.5 | NI | 13.04 | 14.10 | 13.13 | 13.68 |  |
| 330 | 31.5 | NI | 17.53 | 19.20 | 17.39 | 18.56 |  |
| 330 | 31.5 | NI | 27.99 | 45.98 | 28.90 | 41.30 |  |
| 330 | 31.5 | NI | 16.74 | 10.71 | 16.18 | 16.10 |  |
| 760 | 31.5 | NI | 37.22 | 42.31 | 36.98 | 41.15 |  |
| 760 | 31.5 | NI | 11.43 | 12.31 | 11.32 | 12.06 |  |
| 760 | 31.5 | NI | 34.67 | 38.35 | 34.41 | 37.45 |  |

Table 129 – 3ph short-circuit current levels for 2015 (4/4)

to third parties is forbidden without prior written approval
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

| Node Name | Voltage kV | Breaker rating kA | Country Name | 2020 kA | 2025 kA | Node Name | Voltage kV | Breaker rating kA | Country Name | 2020 kA | 2025 kA |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| AEROPO008 | 90 | 25 | SE | 8.5 | 10.9 | FANA\_05 | 150 | 25 | MA | 1.9 | 2.1 |
| BELAIR08 | 90 | 25 | SE | 12.4 | 18.9 | KALABA05 | 150 | 25 | MA | 5.1 | 7.3 |
| CAPEIB08 | 90 | 25 | SE | 15.8 | 26.2 | KAYES\_03 | 125 | 31.5 | MA | 4.9 | 5.1 |
| DAGAMA03 | 225 | 31.5 | SE | 2.4 | 2.6 | KENIE03 | 150 | 25 | MA | 3.5 | 4.3 |
| GBU1\_08 | 90 | 25 | SE | 10.4 | 14.1 | KODIA03 | 150 | 31.5 | MA | 4.6 | 6.4 |
| FICT2\_08 | 90 | 25 | SE | 6.1 | 9.7 | KODIA03 | 150 | 25 | MA | 5.2 | 7.3 |
| HANN\_08 | 90 | 25 | SE | 14.2 | 22.1 | KOUTIA03 | 225 | 31.5 | MA | 2.1 | 2.4 |
| KAOLAC03 | 225 | 31.5 | SE | 4.1 | 5.0 | LAFA05 | 150 | 25 | MA | 4.7 | 6.5 |
| KOUNOU03 | 225 | 31.5 | SE | 7.5 | 9.5 | MANANT03 | 225 | 31.5 | MA | 7.3 | 8.4 |
| KOUNOU08 | 90 | 25 | SE | 16.5 | 24.9 | OULLESS03 | 225 | 31.5 | MA | 3.5 | 3.5 |
| MATAM\_03 | 225 | 31.5 | SE | 2.1 | 2.2 | SEGEOU\_03 | 225 | 31.5 | MA | 1.4 | 1.6 |
| MATAM\_08 | 90 | 25 | SE | 3.9 | 3.9 | SEGEOU\_05 | 150 | 25 | MA | 1.6 | 1.9 |
| MBU0\_08 | 90 | 25 | SE | 12.5 | 18.2 | SEGEOU\_07 | 150 | 25 | MA | 3.5 | 4.0 |
| MBOUR\_03 | 225 | 31.5 | SE | 3.0 | 3.2 | SELING05 | 150 | 25 | MA | 3.5 | 5.3 |
| MECKHE08 | 90 | 25 | SE | 2.5 | 2.6 | SIKASSO3 | 225 | 31.5 | MA | 3.8 | 4.7 |
| PATTED08 | 90 | 25 | SE | 12.6 | 18.5 | SIRAKO05 | 150 | 25 | MA | 5.2 | 7.9 |
| SAKAL\_03 | 90 | 25 | SE | 2.9 | 3.2 | TKTKA\_03 | 225 | 31.5 | MA | 4.6 | 6.2 |
| SENDDOU03 | 225 | 31.5 | SE | 7.7 | 9.6 | BIKONGO3 | 225 | 31.5 | SL | 2.1 | 3.9 |
| SIBA\_08 | 90 | 25 | SE | 6.1 | 7.2 | BUMBUN03 | 225 | 31.5 | SL | 2.8 | 3.9 |

to third parties is forbidden without prior written approval
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

| Node Name | Voltage kV | Breaker rating kA | Country Name | 2020 kA | 2025 kA | Node Name | Voltage kV | Breaker rating kA | Country Name | 2020 kA | 2025 kA |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 2210RVI | 90 | 25 | CI | 20.4 | 23.8 | 1120DBUA | 161 | 31.5 | GH | 8.6 | 8.7 |
| 2220BIAS | 90 | 25 | CI | 20.7 | 26.6 | 1130KUMA | 161 | 31.5 | GH | 10.6 | 10.8 |
| 2229YOPO | 225 | 31.5 | CI | 13.7 | 17.1 | 1138T261 | 161 | 31.5 | GH | 4.9 | 4.9 |
| 2239YOPO | 90 | 25 | CI | 16.2 | 19.0 | 1139K2BS | 161 | 31.5 | GH | 8.9 | 8.9 |
| 2231YOPO | 90 | 25 | CI | 14.8 | 16.3 | 1139K2BS | 161 | 31.5 | GH | 11.2 | 11.4 |
| 2240TREI | 90 | 25 | CI | 22.7 | 27.7 | 1140NKAW | 161 | 31.5 | GH | 8.2 | 8.4 |
| 2250YAMO | 90 | 25 | CI | 2.9 | 2.9 | 1150TAFO | 161 | 31.5 | GH | 9.7 | 10.3 |
| 2260DIMB | 90 | 25 | CI | 2.8 | 2.9 | 1160AKWA | 161 | 31.5 | GH | 4.6 | 4.7 |
| 2270ATAK | 90 | 25 | CI | 1.2 | 1.2 | 1170KPON | 161 | 31.5 | GH | 17.2 | 20.4 |
| 2280ABEN | 90 | 25 | CI | 1.1 | 1.1 | 1180KONO | 161 | 31.5 | GH | 5.4 | 5.4 |
| 2290AGNE | 90 | 25 | CI | 1.0 | 1.0 | 1190KPON | 161 | 31.5 | GH | 11.6 | 13.2 |
| 2300SERE | 90 | 25 | CI | 0.9 | 0.9 | 1200ASAW | 161 | 31.5 | GH | 5.1 | 5.1 |
| 2320AVO | 90 | 25 | CI | 2.3 | 2.4 | 1210IAQB | 161 | 31.5 | GH | 3.5 | 3.5 |
| 2320GAGN | 90 | 25 | CI | 1.9 | 1.9 | 1210-OB | 161 | 31.5 | GH | 9.7 | 9.7 |
| 2330ZUEN | 90 | 25 | CI | 1.3 | 1.3 | 1220ASIE | 161 | 31.5 | GH | 5.7 | 6.1 |
| 2340BOUA | 90 | 25 | CI | 4.9 | 5.0 | 1252KPAN | 161 | 31.5 | GH | 2.5 | 2.5 |
| 2350MARA | 90 | 25 | CI | 1.3 | 1.3 | 1260TECH | 161 | 31.5 | GH | 7.5 | 7.6 |
| 2360KORH | 90 | 25 | CI | 2.2 | 2.5 | 1270SUNY | 161 | 31.5 | GH | 5.8 | 5.8 |

Table 131 – 3ph short-circuit current levels for 2020 and 2025 (2/3)

to third parties is forbidden without prior written approval
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

| Node Name | Voltage kV | Breaker rating kA | Country Name | 2020 kA | 2025 kA | Node Name | Voltage kV | Breaker rating kA | Country Name | 2020 kA | 2025 kA |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 30101LOM | 330 | 31.5 | TB | 7.6 | 9.5 | DELTA\_02 | 330 | 31.5 | NI | 14.2 | 14.2 |
| 3010LOME | 161 | 31.5 | TB | 11.9 | 19.7 | DELTA\_06 | 132 | 25 | NI | 9.5 | 7.2 |
| 3020MOME | 161 | 31.5 | TB | 8.6 | 9.4 | EGBEMA01 | 760 | 31.5 | NI | 7.6 | 9.9 |
| 3030COTO | 161 | 31.5 | TB | 15.8 | 16.2 | EGBEMA02 | 330 | 31.5 | NI | 22.9 | 28.6 |
| 3040SAKA | 161 | 31.5 | TB | 18.2 | 18.5 | EGBIN\_02 | 330 | 31.5 | NI | 31.4 | 39.4 |
| 3040SONG | 161 | 31.5 | TB | 9.9 | 9.9 | EGBIN\_06 | 132 | 25 | NI | 14.8 | 18.1 |
| 3060PACK | 161 | 31.5 | TB | 5.6 | 5.2 | EPIN\_02 | 330 | 31.5 | NI | 13.1 | 21.4 |
| 3ATAK16I | 161 | 31.5 | TB | 3.3 | 3.2 | ERUNKA01 | 760 | 31.5 | NI | 8.9 | 9.7 |
| 3BOHHi16I | 161 | 31.5 | TB | 3.8 | 3.7 | ERUNKA02 | 330 | 31.5 | NI | 29.0 | 35.8 |
| 3DJUi16I | 161 | 31.5 | TB | 1.8 | 1.8 | EYAEN\_02 | 330 | 31.5 | NI | 33.1 | 42.1 |
| 3KARA16I | 161 | 31.5 | TB | 2.0 | 2.0 | GANMO\_02 | 330 | 31.5 | NI | 10.5 | 10.8 |
| 3LOME16I | 161 | 31.5 | TB | 8.3 | 11.4 | GBARANO2 | 330 | 31.5 | NI | 7.7 | 8.1 |
| ADJAAR04 | 161 | 31.5 | TB | 6.1 | 6.4 | GBARANO6 | 132 | 25 | NI | 11.8 | 12.0 |
| AVA\_\_04 | 161 | 31.5 | TB | 8.1 | 6.2 | GEREGU02 | 330 | 31.5 | NI | 20.3 | 23.1 |
| BEMBER04 | 161 | 31.5 | TB | 1.8 | 1.8 | GOMBE\_1 | 760 | 31.5 | NI | 3.0 | 3.0 |
| DAPAON04 | 161 | 31.5 | TB | 1.8 | 1.8 | GOMBE\_02 | 330 | 31.5 | NI | 6.9 | 7.1 |
| JAUE16I | 161 | 31.5 | TB | 2.5 | 2.5 | GOMBA02 | 330 | 31.5 | NI | 15.9 | 16.4 |
| KANDI\_04 | 161 | 31.5 | TB | 2.0 | 2.0 | KEJAW02 | 330 | 31.5 | NI | 30.4 | 36.7 |

Table 132 - 3ph short-circuit current levels for 2020 and 2025 (3/3)

to third parties is forbidden without prior written approval
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

# 5\. APPENDIX: DYNAMIC STUDIES: TRANSIENT STABILITY ANALYSIS: CRITICAL CLEARING

# TIMES RESULTS

to third parties is forbidden without prior written approval

ny duplication or transmission

This document is the property of Tractebel Engineering S.A. A

MP-WAPP/4NT/221291/002/00 October 2011 258/273

* * *

| Node Name | Voltage kV | Country Name | CCT calculations without line tripping |  |  | CCT calculations with line tripping |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| min | max | Machines losing synchroism | Faulted line tripped | min | max | Machines losing synchroism |  |  |  |
| KAOLAC03 | 225 | SE | 222 | 225 | KAHONG71/72/73/74 | BIRKEL03\_SOMA\_03\_1 | 184 | 188 | CAPD11A |
| BELAIR08 | 90 | SE | 269 | 272 | GAMB\_EQG | BELAR08\_HANN\_08\_1 | 268 | 272 | GAMB\_EQG |
| CAPEBI08 | 90 | SE | 234 | 237 | GAMB\_EQG | CAPEBI08-SOCIO108\_1 | 230 | 234 | ROSSEBE1/2G |
| COUNU08 | 90 | SE | 263 | 264 | GAMA\_H1/2 | CAPEBI08-KOUNU08/8 | 260 | 264 | KENE\_1G/2G/3G + BALIDG1/2 |
| COUNU08 | 90 | SE | 272 | 273 | GAMB\_EQG | CAPEBI08-SOCIO108/8 | 260 | 264 | ROSSEBE1/2G |
| DAGANA03 | 225 | SE | 222 | 231 | ROSSEBE1/2G | DAGANA03-SAKAL\_03\_1 | 260 | 264 | ROSSEBE1/2G |
| TAMBA03 | 225 | SE | 222 | 231 | KOUDI\_1G/2G | BIRKEL03\_TAMBA03\_1 | 500 |  |  |
| ZIGJUN03 | 225 | SE | 500 |  |  | TANAF\_03\_ZIGJUN03\_1 | 500 |  |  |
| BRIKAM03 | 225 | GA | 500 |  |  | SOMA\_03\_BRIKAM03\_1 | 500 |  |  |
| BISSAU03 | 225 | GB | 381 | 384 | GBISSEQG | BISSAU03\_MANSOA03\_1 | 382 | 386 | GBISSEQG |
| DONKEA07 | 110 | GU | 394 | 394 | DONNEAIG1/2 | GRCHUT07-MANEOA1/7 | 424 | 428 | MANEOA1/2/3 |
| DRAPTA07 | 101 | GU | 384 | 384 | GAMB\_EQG | LINBANG04-GARAB1/7 | 278 | 279 | MANEOA1/2/3 |
| GRHUT07 | 110 | GU | 287 | 287 | MANEAHG1/2/3 | GRCHUT07-GARAB1/7 | 276 | 279 | MANEOA1/2/3 |
| MATOT007 | 110 | GU | 234 | 237 | BUCHANG1 | GRCHUT07-MATOT007/1 | 234 | 238 | MANEOA1/2/3 |
| FOMI\_03 | 225 | GU | 500 |  |  | KOROUS03-FOMI\_03/1 | 500 |  |  |
| KALETA07 | 225 | GU | 272 | 275 | BUCHANG1 | KALETA03-LINSAN03/1 | 176 | 180 | GAMB\_EQG |
| SAMBAG03 | 225 | GU | 500 |  |  | SAMBANG03-MALL\_1/3 | 500 |  |  |
| DABOLA03 | 225 | GU | 500 |  |  | DABOLA03-KOROUS03/1 | 500 |  |  |
| SEGUA03 | 150 | MA | 544 | 247 | MANANA11A/12A/13A/14A/15A + FELOU\_1G/2G/3G | FANA\_03\_SEGQU\_05/1 | 0 | MANANA11A/12A/13A/14A/15A + FELOU\_1G/2G/3G |  |

Table 133 – Critical clearing times for the Base case, with and without lines tripping (1/2)

prior written approval
to third parties is forbidden without
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

| Node Name | VoltageKV | CountryKV | CCT calculations without line tripping |  |  | Faulted line tripped | CCT calculations with line tripping |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| min | max | Machines losing synthronism | min | max | Machines losing synthronism |  |  |  |  |  |
| OUAAGE08 | 90 | BU | 228 | 231 | MANASEMA | PATD01B0-QUAAGE08-1 | 226 | 230 | MANASEMA |  |
| 1010AK05 | 161 | GH | 228 | 231 | MANASEMA | 1010AK04-1190KPON-1 | 226 | 1010AK04-1190KPON-1 | 226 | 1010AK04-1190KPON-1 |
| 1040TEMA | 161 | GH | 319 | 322 | BUCHANG1 | 1020VOLT-1040TEMA-1 | 341 | 344 | BUSHR2G23/4/5/6/7 |  |
| 1190KPON | 161 | GH | 438 | 441 | KPDONGH1/2/3/4 | 1010AK04-1190KPON-1 | 405 | KPONGH1/2/3/4 | 405 | KPONGH1/2/3/4 |
| 1320ABOA | 161 | GH | 278 | 281 | ROSSEG1E/2/3/4 | 1090TARK-1320ABOA-1 | 276 | 279 | ROSSEG1E/2/3/4 | 276 |
| 1600DPB-1 | 161 | GH | 500 |  | ROSSEG1E/2/3/4 | 1600DPB-1750BONY-1 | 100 |  |  |  |
| 1610AKE119 | 161 | GH | 347 | 350 | BUSHR2G2/2/4/5/6/7 | 1010AKE119-1090KPON-1 | 344 |  |  |  |
| 1700ASOG | 161 | GH | 309 | 313 | MANANA1E/2/134A/14/15A | 1700ASOG-1021SME2-1 | 310 | 314 | MANANA1E/2/134A/14/15A | 314 |
| ABOA\_330 | 330 | GH | 325 | 328 | ROSSEG1E/2/3/4 | 1029VOLT-ABOA330-1 | 291 | 295 | ROSSEG1E/2/3/4 | 291 |
| 1500BUI | 161 | GH | 225 | 228 | BUI\_ G1/2 | 1500BUI-1590KIN | 211 | 215 | BUI\_ G1/2 | 211 |
| 1750BONY | 161 | GH | 415 | 419 | DOMY1G1/2 | 1750BONY-1800ELUB-1 | 405 | DOMY1G1/2 | 405 | DOMY1G1/2 |
| 3030COTO | 161 | TB | 250 | 259 | MA\_GLE3G | MA\_GLE4\_3030COTO\_3 | 257 | 260 | MA\_GLE3G | 260 |
| 3010LOME | 161 | TB | 500 |  | MA\_GLE3G | 1392AFT-3010LOME-1 | 500 |  |  |  |
| 3010MANGA | 161 | TB | 284 | 287 | 3061NANG/2NANG | 3061MANGA-3020MANGA-1 | 276 |  | 379 | 3061NANG/2NANG |
| 310LOME161 | 161 | TB | 500 |  | 3061NANG/310LOME161 | 3010LOME-310LOME161 | 500 |  |  |  |
| 3KARA161 | 161 | TB | 500 |  |  | 3ATAK161-3XARA161 | 500 |  |  |  |
| PARAK004 | 161 | TB | 500 |  |  | PARAK004-3050SONIG\_1 | 500 |  |  |  |

Table 134 - Critical clearing times for the Base case, with and without lines tripping (2/2)

prior written approval
to third parties is forbidden without
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

| Node Name | Voltage kV | Country kV | CCT calculations with line tripping |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| Faulted line tripped | max | max Machines lossing synthism | Faulted line tripped | max | max Machines losing synthism |  |  |  |  |
| KAOALAC03 | 225 | SE | BIRKEL03\_SOMA\_03\_1 | 184 | 188 | CPDB11A | BIRKEL03\_SOMA\_03\_1 | 192 | 196 |
| BAILER08 | 90 | SE | BELIAIR08-HANN\_08-1 | 268 | 272 | GAMB\_EQW | BELIAIR08-HANN\_08-1 | 274 | 278 |
| CAPE伯08 | 90 | SE | CAPE伯08-SCOCID08 | 230 | 234 | ROSSBE1G/2/6 | CAPE伯08-SCOCID08 | 243 | 247 |
| CAPE伯08 | 90 | SE | CAPE伯08-SCOCID08 | 260 | 272 | ROSSBE1G/2/6 + BALIDG1/2 | CAPE伯08-KUIT04 | 283 | 293 |
| SOCCID08 | 90 | SE | CAPE伯08-SCOCID08 | 222 | 226 | ROSSBE1G/2/6 | CAPE伯08-SCOCID08 | 289 | 293 |
| DAGANA03 | 225 | SE | DAGANA03-SAKAL\_03-1 | 260 | 264 | ROSSBE1G/2/6 | DAGANA03-SAKAL\_03-1 | 258 | 262 |
| TAMBA03 | 225 | SE | BIRKEL03-TAMBA03\_01 | 260 | 264 | ROSSBE1G/2/6 | BIRKEL03-TAMBA03\_01 | 258 | 262 |
| ZIGJUN03 | 225 | SE | TANAF\_03-ZIGJUN03\_01 | 260 |  |  | TANAF\_03-ZIGJUN03\_01 | 250 |  |
| BIKRAM03 | 225 | SE | SOMA\_03-BRIKAM03\_01 | 500 |  |  | SOMA\_03-BRIKAM03\_01 | 500 |  |
| BISSAU03 | 225 | GB | BISSAU03-MANSOA03\_1 | 382 | 366 | GBSEQW | BISSAU03-MANSOA03\_1 | 383 | 387 |
| DOAIT04 | 110 | SE | GRCHUT07-DONNEA07 | 428 | 428 | MANEAH1G/2/13 | GRCHUT07-DONNEA07 | 383 | 387 |
| GARAP07 | 110 | SE | LINSAN7-GARAF07-1 | 328 | 329 | GRARAF1G/2/13 | LINSAN7-GARAF07-1 | 326 | 329 |
| GRCHUT07 | 110 | SE | GRCHUT07-GARAF07-1 | 276 | 279 | MANEAH1G/2/13 | GRCHUT07-GARAF07-1 | 278 | 282 |
| MATOT007 | 110 | GU | GRCHUT07-MATOT007-1 | 234 | 238 | MANEAH1G/2/13 | GRCHUT07-MATOT007-1 | 235 | 239 |
| FOMI\_03 | 225 | GU | KOROU503-FOMI\_03-1 | 500 |  |  | KOROU503-FOMI\_03-1 | 500 |  |
| KALETA03 | 225 | GU | KALETA03-LINSAN03-1 | 176 | 180 | GAMB\_EQW | KALETA03-LINSAN03-1 | 161 | 165 |
| SAMBAG03 | 225 | GU | SAMBAG03-MALL-03-1 | 500 |  |  | SAMBAG03-MALL-03-1 | 500 |  |
| DAAQA03 | 225 | GU | DAAQA03-KOOGUS03 | 500 |  |  | DAAQA03-KOOGUS03 | 500 |  |

Table 135 - Critical clearing times for the Base case, with lines tripping, improvements with PSS (1/2)

prior written approval
to third parties is forbidden without
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

| Node Name | Voltage kV | Country Name | Faulted line tripped | CCT calculations with line tripping min max Machines losing synthism |  |  | CCT calculations with line tripping min max Machines losing synthism |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| OUAGAEB0 | 90 | BU | PATD0108-UAQAGE08-1 | 226 | 230 | MANASEMA | PATD0108-UAQAGE08-1 | 227 | 231 | MANASEMA |
| 1010AK05 | 61 | GH | 1010AK05-1190KPON-1 | 226 | 230 | MANASEMA | 1010AK05-1190KPON-1 | 229 | 243 | BUSH2G2/3/4/5/6 |
| 1040TEMA | 161 | GH | 1020VOLT-1040TEM-1 | 341 | 344 | BUSH2G2/3/4/5/6/7 | 1020VOLT-1040TEM-1 | 332 | 336 | BUSH2G2/3/4/5/6 |
| 1090KON2 | 161 | GH | 1090TKAR-1320A0B4-1 | 276 | 279 | ROSSEB1G2G | 1090TKAR-1320A0B4-1 | 402 | 425 | BUSH2E1/2G |
| 1600OPB-1 | 161 | GH | 1600PPB-1750BONY-1 | 500 | 500 |  | 1600PPB-1750BONY-1 | 500 |  |  |
| 1470T17P | 161 | GH | 10215ME2-1470T11P-2 | 344 | 344 | MANASEMA | 10215ME2-1470T11P-2 | 364 | 367 | BUSH2G2/3/4/5/6 |
| 1700ASOG | 310 | GH | 1700ASOG-10215ME2-1 | 310 | 314 | MANASEMA | 1700ASOG-10215ME2-1 | 328 | 332 | BABOA33C1 |
| ABOA33C1 | 300 | GH | 1029VOLT-ABOA330-1 | 291 | 295 | BUSH2G2/3/4/5/6/7 | 1029VOLT-ABOA330-1 | 360 | 364 | BABOA33C1 |
| 1750BONY | 161 | GH | 1500UKU-1500UKN-1 | 211 | 211 | BUI G1J2 | 1500UKU-1500UKN-1 | 210 | 210 | DOMIT1G1/2 |
| 3030COTO | 161 | TB | MA GLE4\_0303COTO\_3 | 405 | 409 | DOMIT1G1/2 | 1750BONY-1800EUUB-1 | 406 | 410 | MAGE3G |
| 3010LOME | 161 | TB | 1392AFT-3010LOME-1 | 500 |  |  | MA GLE4\_0303COTO\_3 | 254 | 258 | MAGE3G |
| 3060NAMG | 161 | TB | 3060NAMG-3020MOME-1 | 276 | 279 | 3061NAMG/2NANG | 3060NAMG-3020MOME-1 | 250 |  |  |
| 310LOME161 | 161 | TB | 3010LOME-310LIME161-1 | 500 |  |  | 3010LOME-310LIME161-1 | 500 |  |  |
| PARAKE04 | 161 | TB | ZATAK1\_3XARA161-1 | 500 |  |  | ZATAK1\_3XARA161-1 | 500 |  |  |
| PARAKE04 | 161 | TB | PARAKE04\_3050UNG1-1 | 500 |  |  | PARAKE04\_3050UNG1-1 | 500 |  |  |
| MANGO\_04 | 161 | TB | MANGO\_04\_DAPAON04\_1 | 500 |  |  | MANGO\_04\_DAPAON04\_1 | 500 |  |  |

Table 136 - Critical clearing times for the Base case, with lines tripping, improvements with PSS (2/2)

prior written approval
to third parties is forbidden without
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

| Node Name | Voltage kV | Country Name | CCT calculations without line tripping |  |  | CCT calculations with line tripping |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| MIN | MAX | MACHINES | line tripped | MIN | MAX | MACHINES |  |  |  |
| KAOAC03 | 225 | SE | 215 | 219 | ALBATRIG | BIRKEL03\_SOMA\_03\_1 | 215 | 219 | ALBATRIG |
| BELAIR08 | 90 | SE | 231 | 235 | ALBATRIG | BELAIR08\_HANN\_08\_1 | 231 | 235 | ALBATRIG |
| CAPEBI08 | 90 | SE | 173 | 176 | ALBATRIG | CAPEBI08\_SOCCO08\_1 | 173 | 176 | ALBATRIG |
| KOUNU0408 | 90 | SE | 208 | 212 | ALBATRIG | CAPEBI08\_KOUNU0408\_1 | 208 | 212 | ALBATRIG |
| SGOCC08 | 90 | SE | 208 | 212 | ALBATRIG | CAPEBI08\_SGOCC08\_1 | 204 | 208 | ALBATRIG |
| DAGANA03 | 225 | SE | 254 | 258 | ALBATRIG | DAGANA03-SAKAL\_03\_1 | 0 | ALBATRIG | ALBATRIG |
| TAMBAC03 | 225 | SE | 239 | 243 | KOUDI\_1G/2G | BIRKEL03\_TAMBAC03\_1 | 484 | 488 | ALBATRIG |
| ZIGUIN03 | 225 | SE | 500 |  |  | TANAF\_03\_ZIGUIN03\_1 | 500 |  |  |
| BRIKAM03 | 225 | SE | 500 |  |  | SOMA\_03\_BRIKAM03\_1 | 500 |  |  |
| BISSAU03 | 225 | GB | 500 |  |  | BISSAU03\_MANSOA03\_1 | 204 |  |  |
| DQNEA07 | 110 | GU | 227 | 243 | BUHRD1G | GRCHUT07-DONNEA07\_1 | 208 | BUHRD1G | BUHRD1G |
| GARAF07 | 110 | GU | 227 | 231 | BUHRD1G | LNSA07-GARAF07\_1 | 227 | 231 | BUHRD1G |
| GRCHUT07 | 110 | GU | 176 | 180 | BUHRD1G | GRCHUT07-GARAF07\_1 | 184 | 188 | BUHRD1G |
| MATOT007 | 110 | GU | 165 | 169 | BUHRD1G | GRCHUT07-MATOT007\_1 | 169 | 173 | BUHRD1G |
| FOML\_03 | 225 | GU | 500 |  |  | KOROU503-FOML\_03\_1 | 500 |  |  |
| KALETA03 | 225 | GU | 500 |  |  | KALETA03-LINSAN03\_1 | 500 |  |  |
| SABMBAG03 | 225 | GU | 500 |  |  | SABMBAN03-MALL\_03\_1 | 500 |  |  |
| DAOBJA03 | 225 | GU | 500 |  |  | DAOBJA03-KOONU03\_1 | 500 |  |  |
| MANANT03 | 225 | MA | 192 | 196 | ALBATRIG | MANANT03\_TKITA\_03\_1 |  | 0 | MANAN11A12/13A/14A/15A + FELOU\_1G/2G/3G |
| SEGOU\_05 | 150 | MA | 500 |  |  | FANA\_05\_SEGUO\_05\_1 | 500 |  |  |

Table 137 - Critical clearing times for Scenario 2, with and without lines tripping (1/2)

prior written approval
to third parties is forbidden without
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

| Node Name | Voltage kV | Country Name | CCT calculations without line tripping |  |  | CCT calculations with line tripping |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| MIN | MAX | MACHINES | line tripped | MIN | MAX | MACHINES |  |  |  |
| OUAAGE08 | 91 | BU | 500 |  |  | PATD008-QUAAGE08-1 | 500 |  |  |
| 1010AKOS | 160 | GH | 102 | 106 | ALAOJT4 | 1010AOKA-1190KPON-1 | 102 | 106 | AFAMGT15/16/17/18 + ALAOJT4 |
| 1040TEMA | 161 | GH | 130 | 134 | GOMA\_HG1 | 1020VOLT-1040TEMA-1 | 130 | 134 | GOMA\_HG1 |
| 1190KPON | 161 | GH | 258 | 262 | ALAOJT4 | 1010AOKA-1190KPON-1 | 262 | 26FAMGT15/16/17/18 + ALAOJT4 |  |
| 1320ABOA | 161 | GH | 165 | 169 | BUSHRD1G | 1090TARK-1320ABOA-1 | 165 | 169 | BUSHRD1G |
| 1600OPB | 161 | GH | 500 |  |  | 1600OPB-1750BONY-1 | 500 |  |  |
| 1707TIP | 161 | GH | 161 | 161 | BUSHRD1G | 1021SME-147TTP1P-2 | 162 | 137 | GOMA\_HG1 |
| 1700ASOG | 161 | GH | 126 | 130 | BUSHRD1G | 170AOSOG-1021SME-2 | 126 | 130 | BUSHRD1G |
| ABOA\_330 | 161 | GH | 231 | 235 | GOMA\_HG1 | 1029VOLT-ABOA330-1 | 231 | 235 | BUSHRD1G |
| 1500BUJ | 161 | GH | 212 | 215 | BUI\_\_G1/2 | 1500BUI-1590KU | 204 | 208 | BUI\_\_G1/2 |
| 1750BONY | 161 | GH | 356 | 360 | DOMIT1G1/2 | 1750BONY-1800ELUB-1 | 278 | 282 | BUSHRD1G |
| 3030COTO | 161 | TB | 243 | 247 | CAI\_\_1/G2 | MA\_GLE04\_3030COTO\_3 | 243 | 247 | CAI\_\_1/G2 |
| 3010LOME | 161 | TB | 215 | 219 | LOME\_1G | 1392AFT-3010LOME-1 | 212 | 215 | LOME\_1G |
| 3060AMG | 161 | TB | 278 | 278 | 3060AMG-N2NANG | 2060AMG-N2NANG-1 | 266 | 3060AMG-N2NANG | 2060AMG-N2NANG |
| 3010ME161 | 161 | TB | 301 | 305 | 3NEWIPP | 3010LOME-301ME161-1 | 301 | 305 | 3NEWIPP |
| 3KARA161 | 161 | TB | 500 |  |  | 3ATAK161-3KARA161-1 | 500 |  |  |
| PARAKO04 | 161 | TB | 500 |  |  | PARAKO04\_3050OONG\_1 | 500 |  |  |
| MANGO\_04 | 161 | TB | 500 |  |  | MANGO\_04\_DAPAON04\_1 | 500 |  |  |
| MA\_GLE04 | 161 | TB | 200 | 204 | CAI\_\_1/G2 | 3040SAKA\_MA\_GLE04\_1 | 200 | 204 | CAI\_\_1/G2 |

Table 138 - Critical clearing times for Scenario 2, with and without lines tripping (2/2)

prior written approval
to third parties is forbidden without
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

| Node Name | Voltage kV | Country Name | Faulted line tripped | Base case off peak load |  |  | Scenario 2 off peak load |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| CCT calculations with line tripping min | max | Machines losing synhrism | CCT calculations with line tripping min | max | Machines losing synhrism |  |  |  |  |
| KAOAC03 | 225 | SE | BIRKEL03\_SOMA\_03\_1 | 211 | 205 | FEU01G/2/3G | 217 | 212 GTI\_113A |  |
| BELAIR08 | 90 | SE | BELAIR08\_HANN\_08\_1 | 260 | 264 | BUHRS2G/2/3 | 244 | 248 GTI\_113A |  |
| CAPEBI08 | 90 | SE | CAPEBI08-SOCCI08-1 | 221 | 225 | BUHRS2G/2/3 | 194 | 198 KENE\_1/2/3G |  |
| KOUUN0U8 | 90 | SE | CAPEBI08-KOUN0U8\_0 | 264 | 268 | BUHRS2G/2/3 | 225 | 229 KENE\_1/2/3G |  |
| SOCCI08 | 90 | SE | CAPEBI08-SOCCI08-1 | 299 | 303 | BUHRS2G/2/3 | 264 | 268 GTI\_113A |  |
| DAGANA03 | 225 | SE | DAGANA03-SAKAL\_03\_1 | 237 | 240 | ROSSBEIG | 268 | 272 ROSSBE12G |  |
| TAMBAC03 | 225 | SE | BIRKEL03\_TAMBAC03\_1 | 487 | 490 | KOUDI\_1/2G | 463 | 467 GTI\_113A |  |
| ZIGJUIN03 | 225 | SE | TANAF\_03\_ZIGJUIN03\_1 | 500 |  |  | 500 |  |  |
| BRIKAM03 | 225 | GA | SOMA\_03\_BRIKAM03\_1 | 479 | 483 | BUCHANG1 | 500 |  |  |
| BISSAU03 | 225 | GB | BISSAU03\_MANSOA03\_1 | 500 |  |  | 500 |  |  |
| DONKEA07 | 110 | GU | GRCHUT07-DONEKA07\_1 | 381 | 385 | TOMBO5G2/3 | 283 | 287 BUSHR2G2/3/4 |  |
| GARAFI07 | 110 | GU | LINSAN07-GARAFI07\_1 | 405 | 408 | GARAFIG1 | 330 | 334 BUSHR2G2/3/4 |  |
| GRCHUT07 | 110 | GU | GRCHUT07-GARAFI07\_1 | 280 | 283 | TOMBO3G4 | 237 | 240 GOMA\_HG1/2 |  |
| MATOT07 | 110 | GU | GRCHUT07-MATOT0701\_1 | 240 | 244 | TOMBO3G4 | 213 | 217 BUSHR2G3 |  |
| FOMI\_03 | 225 | GU | KOROUS03-FOMI\_03\_1 | 500 |  |  | 500 |  |  |
| KALETA03 | 225 | GU | KALETA03-LINSAN03\_1 | 61 | 65 | GOMA\_HG1/2 | 500 |  |  |
| SAMBAG03 | 225 | GU | SAMBAG03-HAIL\_03\_1 | 500 |  |  | 500 |  |  |
| BJOBA03 | 225 | GU | DABOA03-KOROUS03\_1 | 500 |  |  | 500 |  |  |
| MANANT03 | 225 | MA | MANANT03\_TKITA\_03\_1 | 287 | 291 | MANAN15A | 283 | 287 MANAN14/5A |  |
| SEGOU\_05 | 150 | MA | FANA\_05\_SEGU03\_1 | 500 |  |  | 500 |  |  |

Table 139 - Critical clearing times for Base case and Scenario 2 off peak load situation, with line tripping (1/2)

prior written approval
to third parties is forbidden without
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

| Node Name | Voltage kV | Country kV | Faulted line tripped | CCT calculations with line tripping |  | CCT calculations with line tripping |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- |
| min max | Machines losing synthronism | min max | Machines losing synthronism |  |  |  |  |  |
| OUAAGE08 | 90 | BU | PATDO08-OUAGAE08-1 | 213 | 217 | MANASEMA | 500 |  |
| 101A0K0 | 161 | GH | 1010AK05-190KPON-1 | 280 | 283 | TOMOBG52 | 225 | GOMA\_HG1/2 |
| 1040TEMA | 161 | GH | 1020VOLT-1040TEMA-1 | 303 | 307 | BUSHR2G2/3/4 | 205 | 209 BUSHR2G3 |
| 1190KPON | 161 | GH | 1010AK05-1190KPON-1 | 500 |  |  | 471 | 475 BUSHR2G2/3/4 |
| 1320ABOA | 161 | GH | 1090TARK-1320ABOA-1 | 291 | 295 | ABOAT1ST | 217 | 221 BUSHR2G3 |
| 1600OPB-1 | 161 | GH | 1600OPB-1750BONY-1 | 500 |  |  | 455 | 459 DOMIT1G1/2 |
| 1470T1P | 161 | GH | 1021SME2-1470T1P-2 | 311 | 315 | BUSHR2G2/3/4 | 213 | 217 BUSHR2G2/3/4 |
| 1700ASOG | 161 | GH | 1700ASOG-1021SME2-1 | 295 | 299 | BUSHR2G2/3/4 | 205 | 209 BUSHR2G2/3/4 |
| ABOA\_330 | 330 | GH | 1029VOLT-ABOA330-1 | 276 | 280 | BUSHR2G2/3/4 | 221 | 225 BUSHR2G3 |
| 1500BUI | 161 | GH | 1500BUI-1590KIN | 229 | 233 | BUI\_G1 | 233 | 237 BUI\_G1 |
| 1750BONY | 161 | GH | 1750BONY-1800EUBL-1 | 389 | 393 | DOMIT1G1/2 | 256 | 260 DOMIT1G1/2 |
| 3030COTO | 161 | TB | MA\_GLE04\_3030COTO\_3 | 287 | 291 | MA\_GLE1G | 295 | 299 MA\_GLE1G |
| 3010LOME | 161 | TB | 1392AFT-3010LOME-1 | 198 | 201 | LOME\_1G | 213 | 217 LOME\_1G |
| 3060NANG | 161 | TB | 3060NANG-3020MOME-1 | 500 |  |  | 500 |  |
| 3LOME161 | 161 | TB | 3010LOME-3LOME161-1 | 303 | 307 | 3NEWIPP | 307 | 311 3NEWIPP |
| 3KARA161 | 161 | TB | 3ATAK161-3KARA161-1 | 500 |  |  | 500 |  |
| 3KARE04 | 161 | TB | PARA0404-300KRE04-1 | 500 |  |  | 500 |  |
| MANGO\_04 | 161 | TB | MANGO\_04\_DAPA04N04\_1 | 500 |  |  | 500 |  |
| MA\_GLE04 | 161 | TB | 3040SAKA\_MA\_GLE04\_1 | 248 | 252 | MA\_GLE1G | 252 | 256 MA\_GLE1G |
| KANDI\_04 | 161 | TB | GUENE\_04\_KANDI\_04\_1 | 500 |  |  | 500 |  |

prior written approval
to third parties is forbidden without
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

6. APPENDIX: NOTE FOR THE HARMONIZATION OF
   THE UNDER FREQUENCY LOAD SHEDDING
   SCHEME IN GHANA, IVORY COAST, BURKINA
   FASO, TOGO AND BENIN

6.1. Introduction

High imbalance in active power/frequency domain can be corrected by suitable
automatic load shedding. The Under Frequency Load Shedding (UFLS) of the different
power systems which are synchronously interconnected have to be coherent. This
coordination is required in order to maximize the chance, to avoid a complete or partial
frequency collapse in the system and to fairly share the load shedding among all systems
making the interconnected system. A coordinated load shedding plan could limit the shed
load in each system by applying the “solidarity” principle: the load is shed not only in the
area where the imbalance occurs but also in the interconnected systems.

The objective of this report is to review and to analyze the existing UFLS schemes of the
WAPP interconnected system and to present some guidelines to harmonize them. Before
this analysis, the international practices and especially the ENTSOE rules are presented.

6.2. International Practice for UFLS scheme

6.2.1. General Guidelines

Concerning the definition of the Under-frequency Load Shedding (UFLS) scheme, the
following main rules are recommended internationally:

• The frequency range of load shedding results from the power-frequency control
policy of the network. It has to be defined between the frequency range kept for
primary frequency control and the frequency threshold to disconnect the generating
units.
The shedding thresholds have to be uniformly distributed in a common frequency

• The higher the number of the frequency steps, the better will be the self adjustment of
the load shedding plan (ability to catch most situations with the minimum possible
load shedding).
• The global amount of load shedding is limited due to the over-voltage problems

• The global amount of load shedding is limited due to the over-voltage problems
arising during and after the frequency restoration.

to third parties is forbidden without prior written approval
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

Concerning the implementation of the under-frequency load shedding scheme, the
following general guidelines should be followed:

• The shed load has to be evenly distributed geographically. This allows limiting power
flows resulting form the load shedding and facing frequency collapse in possible
islands which could appear.
The load shedding program should follow the actual overall load evolution in time so

• The load shedding program should follow the actual overall load evolution in time so
as to maintain the percentage of shed load. The effective load corresponding to the
under-frequency relays has to be regularly checked (mainly if the total load shedding
amount is fairly limited).
The time delays of the frequency relays have to be limited (no addition delay is

• The time delays of the frequency relays have to be limited (no addition delay is
recommended), but an unavoidable delay exists for insuring “stable” frequency
measurements. The typical global time delay is between 100 ms to 200 ms. Using
longer delays is not recommendable because self adjustment of the scheme can get
lost.
A frequency margin is kept between the lowest frequency threshold of the UFLS and

• A frequency margin is kept between the lowest frequency threshold of the UFLS and
the frequency threshold of the under-frequency protection of the generating units
(preferably a single uniform value for all units).

6.2.2. ENTSOE Practices

ENTSOE (European Organization of TSO merging the former UCTE, Nordel, ETSO,…)
is generally considered as a worldwide reference in terms of interconnected system and
harmonization rules and recommendations. This European TSO organization reviewed
recently the basic rules to be followed by each member in terms of Under Frequency
Load Shedding. Those rules are summarized here-below.

UFLS of ENTSOE solidarity range

The automatic load shedding of consumption due to the large drop of frequency for the
UCTE solidarity range is designed as follows:

• Beginning of the solidarity range at 49,2 Hz,
End of the solidarity range at 48.5 Hz with the sum of shed consumption reaching

• End of the solidarity range at 48.5 Hz with the sum of shed consumption reaching
minimum 25% of the initial total consumption before load shedding.
Trigger of load shedding are as follows:

• At 49 Hz at least 5% of total consumption
At 48.8 Hz at least 10% - with a maximum of 20% - of total consumption

• Trigger of load shedding are as follows:
At 49 Hz at least 5% of total consumption

• At 48.8 Hz at least 10% - with a maximum of 20% - of total consumption
At 48.6 Hz at least 15% of total consumption

• At 48.6 Hz at least 15% of total consumption

to third parties is forbidden without prior written approval
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

25% of the total load should be operated under load shedding relays in the range from
48.6 to 49,2 Hz, with an inaccuracy of 100 mHz for old relays.

Load shedding relays (modern type) should be triggered in the range from 48.6 to
49.2 Hz in steps smaller or equal than 200 mHz (old relays type: larger frequency steps
are acceptable with an inaccuracy of 100 mHz)

In each step not more than 10% of the load should be disconnected, except for radial
regions or other local/regional risk assessment.

Individual ranges of load shedding

Additional 25% or more of the total load could be operated under load shedding relays
in the range from 48.6 to 48.0 Hz (regional/individual solution), even till 47.5 Hz based
on the individual appreciation of TSOs.

Load shedding geographical distribution

Load shedding should be implemented in a regionally evenly distributed way.

Time delay of relays

The reaction time should be realized as short as possible under consideration of the
required time constant respectively time delay of the measuring element. The operational
time of relays should not be longer than 200 ms (without time of opening of breakers).

The recommended UFLS scheme can be summarized by the following graph.

A large numbers of international utilities follow those European guidelines to define their
under-frequency load shedding.

to third parties is forbidden without prior written approval
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

6.3. Analysis of Existing UFLS of Ghana

The collected data are the following (2010 data). The given percentages are referring to
peak load situation.

|  | Threshold(Hz) | Thresholddf/dt | Time delay | Load(%) |
| --- | --- | --- | --- | --- |
| 1 | 49.5 | -0.35 | 150ms | 9.5 |
| 2 | 49.5 | -0.6 | 150ms | 9.5 |
| 4 | 49. |  | 150ms | 9.8 |
| 5 | 48.5 |  | 150ms | 7.9 |
| 6 | 48.3 |  | 150ms | 10 |
| TOT |  |  |  | 46.7 |

This analysis of the existing UFLS of Ghana is split into the following parts: the features
respecting the international practices and the ones not following these practices.

6.3.1. Features respecting international practices

The existing global UFLS scheme of Ghana follows the international recommendations
for the following aspects:

• Similar load amount per threshold with maximum 10% per threshold;
Identical and low time delay (<200 ms) for all UFLS thresholds;

• Identical and low time delay (<200 ms) for all UFLS thresholds;
Acceptable first frequency threshold of 49Hz.

• Acceptable first frequency threshold of 49Hz.

6.3.2. Features not according to international practices

The following characteristics of UFLS of Ghana are not following the international
recommendations:

• Insufficient number of UFLS thresholds (only 3 frequency thresholds). A minimum of
5 thresholds is recommended (for example adding two thresholds at 48.8 Hz and 48.1
Hz).
The use of df/dt criteria for UFLS activation is not usual and questionable for the

to third parties is forbidden without prior written approval
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

6.4. Analysis of Existing UFLS of Burkina Faso

The following data are coming from the report « Etude du couplage des réseaux CIE-
SONABEL à la mise en service de la ligne Bobo-Ouaga » (novembre 2009).

|  | Threshold(Hz) | Time delay | Load(%) |
| --- | --- | --- | --- |
| 1 | 49.0 | 500ms | 3.5 |
| 2 | 48.87 | 500ms | 8 |
| 3 | 48.87 | 700ms | 16 |
| 4 | 48.87 | 1.5sec | 10 |
| 5 | 48.87 | 2sec | 12.5 |
| TOT |  |  | 50 |

The existing UFLS should be completely reviewed and is not at all according to
international practices. Its main drawbacks are:

• Only two frequency thresholds within a very narrow range 49Hz – 48.87 Hz;
UFLS having same frequency thresholds with different delays could provoke over-

• UFLS having same frequency thresholds with different delays could provoke overshedding as there is a need for some time to restore the frequency after load shedding;
Large time delays (> 500ms) could provoke a frequency collapse of the system

• Large time delays (> 500ms) could provoke a frequency collapse of the system
especially for a country like Burkina Faso which could import a large proportion of its
consumption.
• Although this is the only country without df/dt criteria, such df/dt criteria could be

• Although this is the only country without df/dt criteria, such df/dt criteria could be
justified from Burkina Faso power system to face sudden loss of interconnection in
case of massive importation.

6.5. Analysis of Existing UFLS of Ivory Coast

The data are coming from the report “Rapport de collecte de données du réseau Ivoirien”
of July 2006.

The main drawbacks of UFLS scheme of Ivory Coast are:

• Not enough number of frequency thresholds. A minimum of 5 steps is recommended;
Bad frequency load shedding range, the first frequency threshold should be

|  | Threshold(Hz) | Thresholddf/dt | Time delay | Load(%) |
| --- | --- | --- | --- | --- |
| 1 | 49.5 | -0.4 | 100ms | 5.5 |
| 2 | 49.5 | -0.6 | 30ms | 5.5 |
| 3 | 49.5 | -1.0 | 10ms | 5.5 |
| 4 | 48.5 |  | 1sec | 5.5 |
| 5 | 48.1 |  | 300ms | 5.5 |
| 6 | 47.7 |  | 0ms | 22 |
| TOT |  |  |  | 47.5 |

• Bad frequency load shedding range, the first frequency threshold should be
harmonized with neighbouring countries (49Hz) for a fair contribution of all countries
and the last threshold of 47.7Hz is too low and probably too close of under-frequency
thresholds of generating units.

to third parties is forbidden without prior written approval
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

• The load shedding amount is not well distributed among thresholds; the last threshold
corresponding to 22%;
All time delays should be lower than 200 ms;

• All time delays should be lower than 200 ms;

• Similarly to Ghana system, it has to be checked if the df/dt criteria are required and
correctly tuned;
If the df/dt thresholds are maintained, they should be coupled with a classical

• If the df/dt thresholds are maintained, they should be coupled with a classical
frequency threshold (OR logic) to ensure a sufficient total load shedding amount in
case of frequency drop with a decrease rate lower than df/dt thresholds (for example
multiple loss of generators with some seconds between each loss).

6.6. Analysis of Existing UFLS of Togo/Benin

No information has been transmitted by GRIDCo concerning the existing UFLS of
Togo/Benin system.

6.7. Recommendations

The UFLS schemes of WAPP countries should be in line with the internationally
recommended practices. The following guidelines are proposed to update the UFLS
scheme of WAPP interconnected system.

• Collect the UFLS settings currently applied in each country with the frequency
thresholds, the operation time delay and the corresponding amount of load shed in
MW for different network situation (peak and off-peak situation). This information
should be centralized and updated regularly.
• Collect the settings of Under-frequency protection of generating units to verify if

• Collect the settings of Under-frequency protection of generating units to verify if
there is a sufficient margin between the last UFLS thresholds and the first UF
protection (at least 200 mHz).
• Perform dedicated studies in order to quantify :

• Perform dedicated studies in order to quantify :
-The global amount of load that could be shed without facing unacceptable

-The global amount of load that could be shed without facing unacceptable
overvoltage problems. As the WAPP interconnected is quite weak and poorly
meshed, this maximum % of load shedding should be lower than the classical
maximal threshold used in European country (between 40% and 50%). It has to be
noticed that some countermeasures could be installed to limit the over-voltages
(like automatic disconnection of bank capacitor or automatic connection of bank
reactor when the last UFLS are activated.
-To review the settings and even the need of the thresholds based on the derivative

-To review the settings and even the need of the thresholds based on the derivative
of frequency (see remarks of the previous section).
Harmonize the UFLS of each country to have a fair and similar contribution of all

-All time delay lower than 200 ms;
-Identical frequency thresholds and at least 5 thresholds;

• Harmonize the UFLS of each country to have a fair and similar contribution of all
member states to the load shedding in case of frequency drop. The guidelines for this
harmonization are:
-No harmonization of df/dt criteria is required. These criteria should be additional

-Identical frequency thresholds and at least 5 thresholds;

to third parties is forbidden without prior written approval
ny duplication or transmission
This document is the property of Tractebel Engineering S.A. A

* * *

\*\*-\*\*Similar load shedding amount expressed in percentage of the total consumption of each country with a maximum of 10% per threshold; UFLS relays have to be evenly distributed geographically and installed in a sufficient number of substations.

to third parties is forbidden without prior written approval

ny duplication or transmission

This document is the property of Tractebel Engineering S.A. A

MP-WAPP/4NT/221291/002/00 October 2011 273/273

* * *

**Tracte bel En gineerin g S.A.** A venue A riane 7 1200 Brussels-BelgiUM [www.tractebel-engineering-gdfsuez.com](http://www.tractebel-engineering-gdfsuez.com/) Y ves BO UFFIO UL X tel. +32 2 773 83 79 fax +32 2 773 88 90 [yves.bouffioulx@gdfsuez.com](mailto:yves.bouffioulx@gdfsuez.com)