NISO Explains Lagos Blackout, Cites 614MW Drop At Egbin Plant

NISO blames Lagos blackout on Egbin’s 614MW generation loss and transmission faults, triggering load shedding to stabilise the national grid.

The Nigerian Independent System Operator (NISO) on Thursday attributed the ongoing reduction in electricity supply to Lagos and its environs to a major generation loss at the Egbin Power Station, which it said triggered ongoing load shedding.

In a statement issued in Abuja NISO said the nation’s largest power plant experienced a significant operational disturbance on April 28, leading to a sharp drop in output.

According to the system operator, at about 8:21 pm on the day, Egbinrecorded a complete loss of generation, falling from approximately 641 megawatts to zero. The incident, it stressed, was linked to a failure of the plant’s central compressor, as well as a malfunction in its circulating water pump system, which forced an emergency shutdown of all generating units.

NISO noted that the situation was compounded by transmission constraints, particularly the forced outage of the Osogbo–Ikeja West 330kV transmission line, which has limited the ability to wheel available power into the Lagos load centre.

It explained that the combined impact of the generation loss and transmission disruption created a significant supply shortfall, making it necessary to implement immediate load shedding measures to stabilise the national grid and avert a wider system collapse.

“NISO wishes to inform the general public of a significant reduction in power generation currently affecting electricity supply across the country, particularly within the Lagos region.

Egbin power station, which is the largest electricity generating plant on the national grid and a major contributor to daily power supply in Nigeria, experienced a major operational disturbance.

“At about 8:21pm on April 28, 2026, the power station recorded a complete loss of generation, dropping from approximately 641MW to zero output. The incident was attributed to a failure of the plant’s central compressor, alongside a malfunction of the circulating water pump system, which necessitated an emergency shutdown of all units.

“In addition, power supply to the Lagos region is currently restricted due to the forced outage of the Osogbo–Ikeja West 330kV line, further constraining the delivery of available generation into the Lagos load centre.

“Consequently, this loss of generation has created a significant supply shortfall, necessitating immediate load shedding measures to maintain grid stability and prevent a wider system disturbance,” it stated.

The system operator said contingency measures have since been activated, including adjustments in load allocation across Distribution Companies (Discos), with priority given to critical infrastructure, while efforts are ongoing to optimise output from other generating stations to cushion the impact.

NISO acknowledged the inconvenience caused to electricity consumers, particularly in Lagos and surrounding areas, and assured that relevant stakeholders are working to restore normal supply as quickly as possible.