[http://dx.doi.org/10.4314/njt.v38i3.28](http://dx.doi.org/10.4314/njt.v38i3.28)

\[Image: Image26\]
OVERVIEW OF ENERGY GENERATION AT JEBBA HYDROPOWER
STATION (2009-2016)

1,\*
A. O. Odesola and T. O. Ale2

1, 2,
DEPARTMENT OF ELECTRICAL AND ELECTRONICS ENGINEERING, FEDERAL UNIVERSITY OF TECHNOLOGY,
P.M.B 704 AKURE, ONDO STATE, NIGERIA
E-mail addresses: [demoluin@yahoo.co.uk](mailto:demoluin@yahoo.co.uk), [toale@futa.edu.ng](mailto:toale@futa.edu.ng)

1 2
E-mail addresses: [demoluin@yahoo.co.uk](mailto:demoluin@yahoo.co.uk), [toale@futa.edu.ng](mailto:toale@futa.edu.ng)

ABSTRACT

This research was carried out to ascertain the relationship between effective reservoir management
and hydropower station performance selecting the Jebba Hydroelectric Power Station as a case
study. In order to achieve this, the daily inflow and outflow data, as well as the generated energy
were collected for the reviewed period (2009 – 2016). The hydrological data indicated that during
period under study, the reservoir is recovering at a very low rate. A further analysis was carried out
by comparing the conversion efficiency of the energy in flowing water and actual energy generated.
Thus the product of the head (metres) and the outflow was plotted against the actual energy
generated. The results satisfied a linear relationship having a correlation coefficient of 0.7059
which reinforces the knowledge of the effects of hydropower reservoir management on energy
generation.

Many scholars have carried out studies on reservoir
inflow and outflow related issues on hydropower
stations, all aimed at proffering solutions to meet the
challenging increasing demand in electricity, some of
these works are discussed below:

Keywords: Conversion Efficiency, Hydroelectric Power, Inflow, Outflow, Power Station, Reservoir.

1. INTRODUCTION

Electrical energy is the most popular form of energy
due to its higher efficiency, better controllability,
easier bulk power, long distance transportation of
power using overhead transmission and underground
cables, user friendly, etc. Electricity came to Nigeria
in 1896, 15 years after it got to England \[1\]. Despite
its long history in Nigeria, electricity generation is still
at its low ebb with power outages being the order of
the day. The demand for electricity in the country far
outstrips the supply \[2\].
At present, the three hydro in the country contributes

The study in \[4\] examined the interaction that exist
within some reservoir elements such as minimum
inflow, storage balance, lake evaporation, average
outflow, peak inflow, peak outflow, reservoir level,
average inflow, minimum outflow and discharge. It
was identified that few elements are most relevant to
electricity generation and their level of relevance
varies from months to month. However, during low
flows the reservoir elements have negligible roles in
power generation. Also, in the flood seasons, the
output terms are dominant indam operations in order
to prevent dam failure and wastage of energy. The
study also revealed that a causal relationship exists
between hydroelectricity and reservoir elements.
The work in \[5\] carried out assessment of climate by \[6\] with the view to assessing its current state,
operations and management. Suggestions were
given as to the other possible ways to reduce siltation
and enhance reservoir performance.
The research in \[7\] investigated the effect of

The research in \[7\] investigated the effect of
reservoir inflow pattern on hydroelectric power
generation in Kainji dam, Niger state, Nigeria.
Investigation was conducted using data on reservoir
inflow and the amount of power generated for the
period of thirty years (1985 -2014) from Kainji
hydropower station. The research indicated that
reservoir inflow has a strong relationship on the
amount of power generated with a correlation
coefficient of 0.92.
In this work, the effects of hydropower water

In this work, the effects of hydropower water
reservoir management on electric power generation
at Jebba hydroelectric power station in Nigeria was
studied.

2. STUDY AREA

3. STUDY AREA
   Niger River is the third longest in Africa, after Nile and
   the Congo/Zaire Rivers, 4100km long and it
   transverses two humid catchments separated by a
   wide expanse of semi – arid environment (\[8\],\[9\]). It
   has a total length of about 4200 km with a theoretical
   area of about 2 million sq km. This area has reduced
   to an active catchment area of just about 1.5 million
   sq km thus excluding Algeria which is among the 10
   countries covered by the Niger River basin. Other
   countries are Benin, Burkina Faso, Cameroon, Chad,
   guinea, Ivory Coast, Mali, Niger, and Nigeria. The
   study area, Jebba hydropower reservoir, is located 64
   miles from the Kainji dam \[10\]. The flow of river Niger
   downstream of Jebba dam is governed by the
   operations of the Kanji and Jebba hydroelectric
   schemes and runoff from the catchments \[11\]. Jebba
   reservoir depends solely on Kainji discharge during
   the black flood (Dec to Mar). During white flood (rainy
   season) some rivers downstream of Kainji discharge
   in Jebba reservoir in addition to Kainji discharge.
   Effective water management policy by the station
   allow the operation of Jebba unit all year round.

4. METHODOLOGY


Hydrological data and energy generated from 2009-
2016 was collated from both National Control Centre,
Osogbo (NCC) and Jebba Hydroelectric Power
Station.
Data relating to energy production as well as

Station (JHPS) was extracted and collated for the
period between2009 and 2016. These data include;
Hydrological data (Inflow, Outflow, Head Water
Elevation, Tail Water Elevation), daily energy
produced, and daily fault occurrence at JHPS. The
collated data was studied using Time series analysis
and Correlation in Microsoft Excel Software
Environment.
The effect of water inflow and the reservoir condition

m^{3}/s

The effect of water inflow and the reservoir condition
on power generation for the studied period were
related using equation (1). The initial value of the
reservoir health variable is arbitrarily set to zero for
easy analysis.
𝑅 = 𝑅 \+ 𝑄 − 𝑄 (1)

R\_{n+1}=R\_{n}+Q\_{i,n}-Q\_{o,n}

where 𝑅𝑛+1is the net cummulative inflow in 𝑚3/𝑠
𝑅𝑛is the reservoir health variable in 𝑚3/𝑠
𝑄 is the inflow at interval 𝑛 in 𝑚3/𝑠

\\cap m^{3}/s

R\_{n+1}

R\_{n}

𝑄𝑖,𝑛is the inflow at interval 𝑛 in 𝑚3/𝑠

𝑄𝑜,𝑛is the outflow at interval 𝑛in 𝑚3/𝑠
𝑛 is the index for the year

\\mathcal{Q}\_{o,n}

𝑛 is the index for the year

A spread sheet procedure in Microsoft Excel software
environment was developed for easy evaluation of
the hydropower conversion efficiency using equation
(2). This was compared with the actual power
generated for efficiency analysis.
𝑃 = 𝜂𝜌𝑔𝑄𝐻 (2)

P=\\eta\\rho g Q

ρ is the density of water (𝑘𝑔/𝑚3)
𝑔 is the acceleration due to gravity (9.81𝑚/𝑠2

where,𝑃 is power in watts.
ρ is the density of water (𝑘𝑔/𝑚3

(k g/m^{3})

𝑔 is the acceleration due to gravity (9.81𝑚/𝑠2)
𝐻 is the effective head of water in (𝑚)

𝐻 is the effective head of water in (𝑚)
𝑄 is the rate of flow of water in (𝑚3/𝑠).

(m^{3}/s)

𝑄 is the rate of flow of water in (𝑚3/𝑠).
𝜂 is the turbine efficiency (%)

4. RESULTS AND DISCUSSION
   Figure 1 shows the plot of the time series of JHPS

Figure 1 shows the plot of the time series of JHPS
daily inflow from January 2009 till December 2016.
The plot indicates a cyclical pattern although not too
strong, indicating two peaks occurring each year.
Seasonal flows are apparent from the time series with
twin peaks occurring annually corresponding to the
black flood and the white floods respectively. The
daily inflow data was later averaged into monthly
scales as shown in Figure 2.
Figure 3 presents both the inflow and the outflow

* * *

OVERVIEW OF ENERGY GENERATION AT JEBBA HYDROPOWER STATION (2009-2016), A. O. Odesola & T. O. Ale

at a very small rate, but if the reservoir is properly is less than the 90% theoretical value for propeller managed, there will be improvement in the recovery type turbines was obtained. rate. A further analysis was carried out by comparing the The time series plot of the monthly power generated conversion efficiency of the energy in flowing water at JHPS is depicted in Figure 5. It shows that the and actual energy generated. Thus the product of the generated power has peaks which are not strictly in head (metres) and the outflow was plotted against step with the inflow as a result of scheduled and the actual energy generated and this is shown in forced outages of the plants in the station. The Figure 6. aggregate efficiency of conversion is 83.79% which

# 6000

# 5000

# 4000

# 3000

# Inflow m3/s2000

# 1000

# 0 1 106211316421526631736841946

# 105111561261136614711576168117861891199621012206231124162521262627312836

_Figure 1: Time Series Of Jebba Inflow 2009-2016_

# days

2000 **Inflow m3/s** 1000

**Months**

Figure 2: Time Series of Jebba monthly inflow 2009-2016

Nigerian Journal of Technology, Vol. 38, No. 3, July 2019

* * *

Figure 3: Time Series of Jebba monthly inflow and outflow 2009- 2016

* * *

Figure 6: Energy vs Head\*outflow

The resulting scatter diagram reveals a cluster of
points almost satisfying a linear relationship but
some strong component deviate from this cluster.
This deviation was well noticed under high outflow
condition, which shows that a significant part of the
outflow was spilled (wasted) rather than used to
operate the turbines for power generation.

5. CONCLUSION

A further analysis was carried out by comparing the
conversion efficiency of the energy in flowing water
and actual energy generated. Thus the product of
the head (metres) and the outflow was plotted
against the actual energy generated.
The results satisfied a linear relationship which

2. Prompt response to faults should be
   ensured.

3. Spares parts should be made readily

4. RECOMMENDATIONS


Having carried out this research, the following were
recommended:

1. The reservoir should be properly managed

2. REFERENCES
   \[1\] Ale, T. O. and Odesola, A. O. “Effects of Distance
   on Transmission (Akure 33kV line a case study)”,
   International Journal of Research Findings in
   Engineering, Science and Technology, Vol. 1,
   No.1., 2013, pp 27-32.
   \[2\] Zungeru, A. M.; Araoye, A. B.; Garegy, B. B.;
   Garba, A. J. and Tola, O. J. “Reliability
   Evaluation of Kainji Hydro-Electric Power Station
   in Nigeria”, Journal of Energy Technologies and
   Policy, Vol.2, No.2, 2012, pp 15-31.
   \[3\] Annual Technical Report -ATR “Grid System
   Operations”, Annual Technical Report Issued by
   National Control Centre Osogbo. 2015, pp 1-86.
   \[4\] Ifabiyi, I. P. “Relationship between Power
   Generation and Reservoir Elements in the Jebba
   Hydroelectric Reservoir, Nigeria”, Global Journal
   of Science Frontier Research, Vol. 11, Issue 8,
   2011, pp. 1-11.
   \[5\] Salami, A. W. and Sule, B. F. “Optimal Water
   Management Modeling for Hydropower System
   on River Niger in Nigeria”, International Journal
   of Engineering, Annals of Faculty of Engineering
   Hunedoara, Tome X, 2012, pp. 185-192.
   \[6\] Adie, D. B.; Ismail, A.; Muhammad, M. M. and
   Aliyu, U. B. “Analysis of the Water Resources
   Potential and Useful life of the Shiroro Dam,
   Nigeria” Nigerian Journal of Basic and Applied
   Science, Vol. 20, No. 4, 2012, pp 341-348.
   \[7\] Adegbehin, A. B, Yusuf Y. O Iguisi E. O and
   Zubairu, I. “Reservoir inflow pattern and its
   effects on hydroelectric power generation at the
   Kainji Dam, Niger State, Nigeria”, Proceeding of
   Vol. 38, No. 3, July 2019 748

3. The reservoir should be properly managed
   to avoid water wastage especially during the
   condition of high water inflow.

4. Prompt response to faults should be

5. Spares parts should be made readily
   available so as to reduce the downtime to
   the barest minimum.

6. REFERENCES
   \[1\] Ale, T. O. and Odesola, A. O. “Effects of Distance the 3rd international conference on
   Environmental and Economic Impact on
   Sustainable Development (EID), Vol. 203, 2016
   pp 233-244.
   \[8\] Alayande, A. W. and Bamigboye, O. A. “Tail
   water Recycling for Hydropower Generation,
   Niger River”, 29th WEDC International
   Conference Abuja Nigeria, 2003, pp 175-177.
   \[9\] Ale, T. O., Alowolodu, K. E., Babatola, J. O. and
   Olufeagba, B. J. “Inflow Forecasting for Kainji
   Dam Using Time Series Model”, International
   Journal of Mathematical Archive (IJMA), Vol. 2,
   No. 12, 2011, pp 2844-2851.


\[10\] Jimoh, O. D. “Optimized Operation of Kainji
Reservoir”, Assumption University Journal of
Technology (AUJ.T.), Vol. 12, No. 3, 2008, pp
34-42.
\[11\] Sule, B. F., Salami, A. W. and Okeola, O. G.
“Operational Impact of Hydropower Generation
and Highlights on Preventive Measures in
Lowland Area of River Niger, Nigeria”,
International Electronic Engineering
Mathematical Society IEEMS, Vol. 7. No 1, 2009,
pp. 109 -126.