# DisCo-Level Grid Emission Factor Calculation — NEFDB Phase 1

## Scope
Derive one location-based grid emission factor (EF) for each of Nigeria's 11 distribution companies (DisCos)
using Q2 2024 DisCo billed energy and a regional generation-mix assumption anchored to 2020 plant-level data.

## Inputs
- DisCo billed energy: `C:\Users\HP\palmgrove\NEFDB\datasets\grid_electricity\derived\disco_billed_energy_latest.csv`
- Plant-level fuel mapping: `NEFDB/datasets/grid_electricity/derived/plant_fuel_mapping.csv`
- National generation by fuel: `NEFDB/datasets/grid_electricity/derived/nigeria_generation_by_fuel_latest.csv`
- IPCC 2006 Guidelines Vol 2 Ch 2 stationary-combustion default EFs

## Data quality note on hydro
The derived `nigeria_generation_by_fuel_latest.csv` reports only 75.593 GWh of hydro for 2020 because the
Kainji, Jebba and Shiroro records carry non-MWh units and were excluded. Independent NERC data indicate
hydro accounted for roughly 23–27% of grid generation in 2020 and ~32–33% in 2024. For this Phase 1
calculation, regional hydro shares were therefore assigned by DisCo territory rather than taken directly from
the incomplete plant-level hydro total.

## DisCo billed energy (Q2 2024)

| DisCo | Billed energy (GWh) | Territory region |
|-------|--------------------:|------------------|
| AEDC | 301.000000 | North-Central (Abuja/FCT, Niger, Nasarawa, Kogi) |
| BEDC | 179.794193 | South-South/East (Edo, Delta, Ondo, Ekiti) |
| EEDC | 159.799076 | South-East (Enugu, Anambra, Abia, Imo, Ebonyi) |
| EKEDC | 317.000000 | South (Lagos) |
| IBEDC | 269.530000 | South-West (Oyo, Ogun, Osun, Kwara) |
| IEDC | 360.322343 | South-West (Lagos) |
| JEDC | 105.605742 | North (Plateau, Bauchi, Benue, Gombe) |
| KDEDC | 83.220000 | North-West (Kaduna, Kebbi, Sokoto, Zamfara, Katsina) |
| KEDC | 124.575763 | North (Kano, Jigawa, Katsina) |
| PEDC | 149.913901 | South-South (Rivers, Cross River, Akwa Ibom) |
| YEDC | 93.852360 | North-East (Adamawa, Taraba, Yobe, Borno) |

## Regional generation-mix assumptions

| DisCo | Gas % | Hydro % | Oil % | Solar % | Other % | Region rationale |
|-------|------:|--------:|------:|--------:|--------:|------------------|
| AEDC | 70 | 30 | 0 | 0 | 0 | AEDC: North-Central (Abuja/FCT, Niger, Nasarawa, Kogi). Hydro share set to 30% based on proximity to Kainji/Jebba/Shiroro hydro plants vs Niger Delta/IPP gas plants. Oil/solar/other treated as zero. |
| BEDC | 76 | 24 | 0 | 0 | 0 | BEDC: South-South/East (Edo, Delta, Ondo, Ekiti). Hydro share set to 24% based on proximity to Kainji/Jebba/Shiroro hydro plants vs Niger Delta/IPP gas plants. Oil/solar/other treated as zero. |
| EEDC | 85 | 15 | 0 | 0 | 0 | EEDC: South-East (Enugu, Anambra, Abia, Imo, Ebonyi). Hydro share set to 15% based on proximity to Kainji/Jebba/Shiroro hydro plants vs Niger Delta/IPP gas plants. Oil/solar/other treated as zero. |
| EKEDC | 88 | 12 | 0 | 0 | 0 | EKEDC: South (Lagos). Hydro share set to 12% based on proximity to Kainji/Jebba/Shiroro hydro plants vs Niger Delta/IPP gas plants. Oil/solar/other treated as zero. |
| IBEDC | 78 | 22 | 0 | 0 | 0 | IBEDC: South-West (Oyo, Ogun, Osun, Kwara). Hydro share set to 22% based on proximity to Kainji/Jebba/Shiroro hydro plants vs Niger Delta/IPP gas plants. Oil/solar/other treated as zero. |
| IEDC | 80 | 20 | 0 | 0 | 0 | IEDC: South-West (Lagos). Hydro share set to 20% based on proximity to Kainji/Jebba/Shiroro hydro plants vs Niger Delta/IPP gas plants. Oil/solar/other treated as zero. |
| JEDC | 68 | 32 | 0 | 0 | 0 | JEDC: North (Plateau, Bauchi, Benue, Gombe). Hydro share set to 32% based on proximity to Kainji/Jebba/Shiroro hydro plants vs Niger Delta/IPP gas plants. Oil/solar/other treated as zero. |
| KDEDC | 66 | 34 | 0 | 0 | 0 | KDEDC: North-West (Kaduna, Kebbi, Sokoto, Zamfara, Katsina). Hydro share set to 34% based on proximity to Kainji/Jebba/Shiroro hydro plants vs Niger Delta/IPP gas plants. Oil/solar/other treated as zero. |
| KEDC | 65 | 35 | 0 | 0 | 0 | KEDC: North (Kano, Jigawa, Katsina). Hydro share set to 35% based on proximity to Kainji/Jebba/Shiroro hydro plants vs Niger Delta/IPP gas plants. Oil/solar/other treated as zero. |
| PEDC | 90 | 10 | 0 | 0 | 0 | PEDC: South-South (Rivers, Cross River, Akwa Ibom). Hydro share set to 10% based on proximity to Kainji/Jebba/Shiroro hydro plants vs Niger Delta/IPP gas plants. Oil/solar/other treated as zero. |
| YEDC | 67 | 33 | 0 | 0 | 0 | YEDC: North-East (Adamawa, Taraba, Yobe, Borno). Hydro share set to 33% based on proximity to Kainji/Jebba/Shiroro hydro plants vs Niger Delta/IPP gas plants. Oil/solar/other treated as zero. |

## IPCC fuel emission factors used

Fuel EFs are from IPCC 2006 Guidelines Vol 2 Ch 2, stationary combustion, net calorific value.

| Fuel | CO2 (kg/TJ) | CH4 (kg/TJ) | N2O (kg/TJ) | GWP basis |
|------|------------:|------------:|------------:|-----------|
| Natural gas | 56100 | 1.0 | 0.1 | AR5 (CH4=28, N2O=265) |
| Hydro | 0 | 0 | 0 | - |
| Solar | 0 | 0 | 0 | - |
| Oil | see IPCC table for residual/gas-diesel oil | see IPCC table | see IPCC table | AR5 (not used; share=0) |

Conversion: 1 TJ = 277,777.78 kWh (1 kWh = 3.6 MJ).

Derived natural-gas EF: 
- CO2: 0.201960 kg CO2/kWh
- CH4: 0.0000036000 kg CH4/kWh × 28 = 0.00010080 kg CO2e/kWh
- N2O: 0.00000036000 kg N2O/kWh × 265 = 0.00009540 kg CO2e/kWh
- **Total gas EF: 0.202156 kg CO2e/kWh**

## Per-DisCo arithmetic

`EF_DisCo = (gas_pct × gas_EF) + (hydro_pct × 0) + (oil_pct × 0) + …`

| DisCo | Billed energy (GWh) | Gas % | Hydro % | EF (kgCO2e/kWh) |
|-------|--------------------:|------:|--------:|----------------:|
| AEDC | 301.000000 | 70 | 30 | 0.141509 |
| BEDC | 179.794193 | 76 | 24 | 0.153639 |
| EEDC | 159.799076 | 85 | 15 | 0.171833 |
| EKEDC | 317.000000 | 88 | 12 | 0.177897 |
| IBEDC | 269.530000 | 78 | 22 | 0.157682 |
| IEDC | 360.322343 | 80 | 20 | 0.161725 |
| JEDC | 105.605742 | 68 | 32 | 0.137466 |
| KDEDC | 83.220000 | 66 | 34 | 0.133423 |
| KEDC | 124.575763 | 65 | 35 | 0.131402 |
| PEDC | 149.913901 | 90 | 10 | 0.181941 |
| YEDC | 93.852360 | 67 | 33 | 0.135445 |

## National-weighted check
- Total DisCo billed energy: 2144.613 GWh
- Billed-energy-weighted national gas share: 77.69%
- Billed-energy-weighted national hydro share: 22.31%
- This is consistent with independent NERC-reported 2020 hydro shares of ~23–27% and 2024 shares of ~32–33%, given that DisCo billed energy is a downstream (not generation) weighting.

## Uncertainty and confidence
- **Uncertainty: ±20%** — driven primarily by the regional-mix assumptions and the incomplete 2020 hydro data.
- **Confidence: medium** — DisCo billed energy is high confidence; generation mix is inferred from territory and national shares, not direct DisCo dispatch data.
- Excluded: T&D losses, own-use/auxiliary consumption, upstream methane venting/leakage from gas supply, and market-based instrument effects.

## Output files
- `C:\Users\HP\palmgrove\NEFDB\datasets\grid_electricity\derived\disco_ef.csv` — flat summary table
- `C:\Users\HP\palmgrove\NEFDB\datasets\grid_electricity\derived\disco_factors.json` — 11 `EmissionFactor` objects ready to merge into `src/factors/grid_electricity.ts`