# Grid-electricity consolidation decision log

Generated: 2026-06-19
Scope: Reconcile all recent research into authoritative Nigeria grid generation datasets (2020–2024) for NEFDB.

## 1. Summary of sources reviewed

| Source | Type | Years available | What it provides |
|---|---|---|---|
| Nigerian Energy Data Bank (NEDB) | Nigeria official plant records | 1962–2022 (partial) | Annual hydro generation by plant (Kainji, Jebba, Shiroro, NESCO). Unit labels required correction. |
| Ember – Yearly Electricity Data | International database | 2000–2024 | Country-level generation by fuel (TWh). |
| Our World in Data (OWID) energy data | International database | 1900–2024 | Same underlying data as Ember for Nigeria. |
| IRENA IRENASTAT | International database | 2020–2023 | Generation by technology (GWh), including renewables, hydro, solar, biomass, oil, gas. |
| World Bank WDI API | International database | 2015–2023 | Share-of-output indicators only (gas, hydro, renewables, oil, coal). |
| IEA Country Profile Nigeria | International / government | 2022 | Total generation and gas/hydro/bioenergy shares. |
| EIA Country Analysis Brief 2025 | International / government | 2023 | Total generation and gas/hydro shares. |
| Guardian Nigeria summary of NERC 2024 data | Nigeria official (via press) | 2024 | Total generation and hydro output for 2024. |
| UNDP Nigeria Energy Finance Assessment (2020) | Alt / development report | 2020 | Gas/hydro shares only, no absolute total. |
| Adoghe et al. (2023) Heliyon | Academic | 2017–2020 | Plant-level hydro GWh; 2020 figures conflict with official records. |
| Okakwu et al. (2019) AZOJETE | Academic | 2008–2017 | Kainji total energy MWh; 2016/2017 values match NEDB. |
| Salisu et al. (2025) IJISETR | Academic | 2012–2022 | Kainji monthly mean values; unit ambiguous and not used. |

## 2. Reconciliation rules used

1. **Use Nigeria official / plant-root data when directly available.** NEDB hydro plant records are preferred for 2020. Guardian Nigeria/NERC figures are preferred for 2024 total and hydro.
2. **Use a consistent international time series for national totals when Nigeria official totals are not available.** Ember/OWID provide an identical, continuous 2020–2024 series and are used as the national total anchor for 2020–2023.
3. **Fill fuel details from the most granular available source.** Solar, biomass and oil are taken from IRENA (2020–2023) and Ember/OWID (2024) because they provide explicit values.
4. **Gas is the residual** after subtracting hydro, solar, wind, biomass, oil and coal from total generation.
5. **Do not invent plant-level data.** Missing years/plants are written as empty cells in the hydro plant file.
6. **When sources conflict, include all candidate rows in the national mix file** and mark the reconciled value with source = `NEFDB reconciled`.

## 3. Year-by-year decisions

### 2020
- **Total:** Ember/OWID 38,000 GWh.
- **Hydro:** NEDB plant sum = 8,341.99 GWh (Kainji 2,953.28 + Jebba 2,678.91 + Shiroro 2,634.21 + NESCO 75.59).
- **Solar/biomass/oil:** IRENA (115.62 / 40.78 / 17.45 GWh).
- **Gas residual:** 29,484.16 GWh.
- **Rationale:** This is the only year with complete official plant-level hydro records. NEDB hydro is ~8.5% higher than Ember hydro (7,690 GWh); the plant-level official sum is preferred.

### 2021
- **Total:** Ember/OWID 39,200 GWh.
- **Hydro, solar, biomass, oil:** IRENA (9,153.81 / 163.60 / 61.12 / 17.45 GWh).
- **Gas residual:** 29,804.02 GWh.
- **Rationale:** NEDB records for Kainji and Jebba stop at 2020, so IRENA hydro is used. NESCO 2021 = 45.66 GWh but is not a full hydro picture.

### 2022
- **Total:** Ember/OWID 38,000 GWh (IEA gives a closely aligned 37,916 GWh).
- **Hydro, solar, biomass, oil:** IRENA (9,235.35 / 207.13 / 59.51 / 20.08 GWh).
- **Gas residual:** 28,477.93 GWh.
- **Rationale:** IEA and Ember/OWID totals are within 0.2%; IRENA provides the fuel breakdown.

### 2023
- **Total:** Ember/OWID 40,920 GWh.
- **Hydro, solar, biomass, oil:** IRENA (9,426.41 / 267.96 / 62.06 / 46.36 GWh).
- **Gas residual:** 31,117.21 GWh.
- **Rationale:** EIA’s Nigeria Brief gives a notably higher total (42,500 GWh) and is included as a candidate. Ember/OWID are retained as the anchor for consistency with the rest of the time series.

### 2024
- **Total and hydro:** Guardian Nigeria / NERC (37,093.70 GWh total; hydro 11,469.85 GWh, 30.92%).
- **Solar/biomass:** Ember/OWID (130 / 60 GWh).
- **Gas residual:** 25,433.85 GWh.
- **Rationale:** Nigeria official NERC-sourced total and hydro are preferred over international estimates. The hydro share is materially higher than Ember/OWID (~24.5%), reflecting the importance of hydropower during the 2024 gas shortfall.

## 4. Plant-level hydro decisions

| Plant | Best source | Coverage | Notes |
|---|---|---|---|
| Kainji | NEDB | 2020 only (1969–2020) | Values treated as MWh. 2020 = 2,953.28 GWh. Adoghe et al. 2020 figure (362.55 GWh) rejected as inconsistent with NEDB/Okakwu. |
| Jebba | NEDB | 2020 only (1986–2020) | Values treated as MWh. 2020 = 2,678.91 GWh. Adoghe et al. 2020 figure (356.66 GWh) rejected. |
| Shiroro | NEDB | 2020–2021 (1990–2021) | Label says Bill.Cubic Meter but numeric magnitudes are MWh. 2020 = 2,634.21 GWh, 2021 = 2,401.20 GWh. Adoghe 2020 figure (331.11 GWh) rejected. |
| NESCO | NEDB | 2020–2022 (1962–2022) | Unit label is MWh but values are actually kWh. 2020 = 75.59 GWh, 2021 = 45.66 GWh, 2022 = 12.71 GWh. |
| Zungeru | — | None | 700 MW commissioned June 2023; no annual GWh record found. |
| Gurara | — | None | 30 MW; typical ~115 GWh/year cited by NSP, but no verified annual series found. |

## 5. Known gaps and conflicts

1. **NEDB hydro records stop in 2020 for Kainji/Jebba, 2021 for Shiroro, 2022 for NESCO.** Filling 2021–2024 plant-level hydro requires NERC quarterly reports, TCN operational data or scraping the Elec-T dashboard.
2. **Gas totals disagree across sources.** EIA 2023 (42,500 GWh) is ~1,580 GWh above Ember/OWID; IRENA 2023 (37,402 GWh) is ~3,500 GWh below. The selected reconciled totals keep the Ember/OWID anchor.
3. **2024 hydro share conflict.** Guardian/NERC reports 30.92% hydro while Ember/OWID reports ~24.5%. The official figure is preferred but it creates a step-change in the series.
4. **Oil/coal/wind generation is negligible** in all sources. IRENA reports small oil-fired generation (17–46 GWh/year) while Ember/OWID report zero.
5. **Adoghe et al. (2023) plant-level hydro figures for 2020 are unusable** without clarification; they are anomalously low compared with NEDB and Okakwu et al. (2019).
6. **World Bank and UNDP provide shares only** and are used for cross-checking rather than as absolute primary sources.

## 6. Recommendation: can we compute a better national location-based EF?

**Yes, for 2020 and 2024; partial for 2021–2023.**

- **2020** now has a strong, plant-level hydro total (8,342 GWh) and a verifiable gas residual (29,484 GWh). The previous NEFDB location-based EF of 0.5717 kgCO₂e/kWh was based on only 75.6 GWh of hydro because Kainji/Jebba/Shiroro were excluded. Recomputing with the reconciled 2020 mix will lower the EF because hydro displaces gas.
- **2024** has an official total and a large hydro share (30.92%). This supports a noticeably lower grid EF than the 2020 value.
- **2021–2023** still rely on international database hydro estimates rather than plant-level Nigerian data. The EF for these years should be flagged as **medium confidence** until NERC/TCN plant dispatch records are obtained.

**Next concrete steps:**
1. Extract 2021–2024 quarterly hydro dispatch from NERC annual/quarterly PDFs or from the Elec-T dashboard.
2. Recompute `location_based_ef.csv` and `grid_electricity.ts` using the reconciled generation mix and the same IPCC 2006 stationary-combustion factors.
3. Add uncertainty bands to the new EF values; keep the 2020 WAPP ASB operating/combined margins as a cross-check.