•Part I: Investigating 8,000–9,000 MW of unavailable capacity

TODAY, I begin a four-part investigation into Nigeria’s power sector, drawing principally on Nigerian Electricity Regulatory Commission (NERC) quarterly reports covering April 2025 to March 2026. The objectives are to trace where Nigeria loses electricity and money; identify the causesand who bears the consequences; and determine what reforms could recover capacity. According to NERC, Nigeria had 13,625 megawatts (MW) of installed grid-connected generation capacity during the period. Yet average available capacity was only 5,395.72 MW in the second quarter of 2025, 5,430.34 MW in the third and 5,400.38 MW in the fourth. By the first quarter of 2026, it had fallen to 4,457.96 MW. In other words, roughly 8,000–9,000 MW of installed generating capacity was unavailable. Where did those megawatts go?

This series follows electricity from installed capacity through availability, generation, transmission, distribution, billing and collection, before asking what taxpayers ultimately subsidise.We begin at the power stations.

Installed capacity versus available capacity

Installed capacity is the maximum output for which a power station is designed and rated. If five generating units are rated at 100 MW each, installed capacity is 500 MW. But turbine failure, maintenance or inadequate gas supply may leave only 200 MW capable of operating, an availability factor of 40 per cent. That 200 MW is not necessarily the plant’s actual generation, as Part II will show. For this analysis, I calculated a day-weighted 12-month availability factor for each of the 28 plants from NERC’s quarterly average available-capacity data, and classified them as Critical—25 per cent or below; Poor—above 25 to 50 per cent; Moderate—above 50 to 75 per cent; and Strong—above 75 per cent. These are my analytical classifications, not NERC ratings.

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Critical: 25 per cent or lower availability

Eleven plants fell into the Critical category. Together, they represented 4,816 MW of installed capacity, but averaged only about 427 MW available, leaving roughly 4,389 MW unavailable. Alaoji, with 500 MW installed, recorded zero availability. Sapele Steam’s 720 MW translated into only about 23 MW average available capacity, or 3.1 per cent. Ibom Power averaged 6.2 per cent, Trans Amadi 6.6 per cent, Olorunsogo II 9.3 per cent, Afam I 9.9 per cent, Omotosho II 10.0 per cent, Ihovbor I 10.9 per cent, Rivers 14.4 per cent, Sapele II 16.6 per cent and Omoku 20.4 per cent.

Poor: Above 25 per cent to 50 per cent availability

Another nine plants fell into the Poor category. Together, they represented 5,080 MW of installed capacity, averaging about 2,040 MW available and leaving roughly 3,040 MW unavailable. Odukpani averaged 28.2 per cent availability, Afam II 29.5 per cent, Olorunsogo I 31.5 per cent, Omotosho I 33.1 per cent, Geregu II 36.0 per cent, Igbafọ 42.4 per cent, Geregu I 47.7 per cent, Delta 48.2 per cent and Egbin 48.4 per cent.

Egbin, Nigeria’s largest grid-connected station, has1,320 MW installed but averaged only about 639 MW available, leaving roughly 681 MW unavailable. Together, the Critical and Poor plants accounted for about 9,896 MW installed, but only about 2,467 MW was available on average. Roughly 7,429 MW of already-built power capacity was therefore unavailable for dispatch and could not be used to power homes, farms, factories and other economic activities.

Moderate: Above 50 per cent to 75 per cent availability

Only four plants were Moderate: Okpai at 58.3 per cent, Shiroro 59.4 per cent, Dadin-Kowa 63.9 per cent and Kainji 66.1 per cent. Okpai was the only thermal plant; the other three were hydro. NERC attributed increased availability at Dadin-Kowa, Zungeru, Shiroro and Jebba in Q3 2025 to rainy-season inflows. In Q1 2026, available capacity across all five hydro plants fell 28.8 per cent, largely because of the dry season, with repairs and maintenance affecting some units.

Strong: Above 75 per cent availability

Only four plants were Strong: Zungeru at 77.1 per cent, Jebba 81.1 per cent, Ihovbor II—Azura-Edo—92.4 per cent and Ikeja/Paras 99.1 per cent. Zungeru and Jebba are hydropower stations; Azura-Edo and Ikeja/Paras are thermal plants.

A striking pattern in global context

All five grid-connected hydropower stations were either Moderate—Kainji, Dadin-Kowa and Shiroro—or Strong—Jebba and Zungeru. By contrast, 20 of Nigeria’s 23 thermal plants were Critical or Poor. Only three thermal plants—Okpai, Azura-Edo and Ikeja/Paras—averaged more than 50 per cent availability. Hydropower faces different constraints and should therefore not be assessed through the same diagnostic lens as thermal generation. Moreover, the 23 thermal plants account for about 80 per cent of Nigeria’s grid-connected installed capacity, yet averaged only about 30 per cent availability during April 2025 to March 2026.

Over exactly the same period, India’s NTPC reported a 90.1 per cent Plant Availability Factor across its 27 coal-fired stations, while South Africa’s broader Eskom generation fleet recorded 65.4 per cent equivalent availability. Burkina Faso’s 11 thermal stations averaged about 72.1 per cent availability during the first half of 2025. The comparison is not perfectly like-for-like because countries use different measures and reporting periods, but the gap is too large to ignore. Nigeria’s own Azura-Edo and Ikeja/Paras, at 92.4 and 99.1 per cent respectively, demonstrate that high thermal-plant availability is achievable here. Recovering much of the country’s missing 8,000–9,000 MW must therefore focus heavily on the thermal fleet.

The question is not whether thermal plants can perform reliably in Nigeria, but why so much of Nigeria’s thermal fleet does not.

Causes

Some units are decades old. Turbines, boilers, generators and auxiliary systems require maintenance, rehabilitation and overhaul. Sapele Steam has undergone repeated rehabilitation, while Afam has required restoration of units out of service for years.

Despite Nigeria’s large gas resources, stations face pipeline limitations, maintenance outages, pressure constraints and other disruptions.NERC itself identifies mechanical and feedstock availability as determinants of plant availability.

The gas problem can also be financial. Ibom Power has linked its gas-supply challenges partly to sector debts owed to the company. Financial stress can turn installed megawatts into unavailable capacity. A financial failure becomes a physical electricity shortage. Alaoji provides an institutional example. The 500 MW station contributed nothing during the study period. NDPHC later explained that it had been shut since 2023 amidgas-supply and metering disputes before returning to service in July 2026.Its total installed capacity remained unavailable while the commercial arrangements required to fuel it were unresolved. That is a governance failure expressed in megawatts.

Recommendations

Every unavailable megawatt should be classified as equipment-related, gas/feedstock-related, commercial/contractual, hydrological/resource-related, planned maintenance or unexplained. The cause must determine the remedy. A turbine failure requires engineering intervention; a pipeline constraint requires gas infrastructure; unpaid gas requires liquidity and commercial reform; an obsolete unit may require retirement or repowering.

The Federal Government, NERC and NISO should make publicly accessible—or establish, if none exists—a Generation Recovery Register for every grid-connected generating unit, showing installed capacity, available capacity, unavailable MW, outage cause and duration, responsible party, estimated recovery cost and expected return-to-service date. Government could then rank interventions by cost per recoverable megawatt, comparing rehabilitation, gas-commercial reforms or maintenance with new greenfield generation.

Power-sector planning should not ask only: How many new megawatts can we build? It should also ask: How many already-built megawatts can we recover, at what cost, and how quickly? Yet even recovering them would not solve Nigeria’s electricity problem. Available capacity can still go unused.

That takes us to Part II: why some available capacity fails to become electricity actually generated and dispatched onto the grid—the megawatts Nigeria has, can produce, but does not use.