The Nigerian Independent System Operator (NISO) has attributed Friday’s national grid collapse to a system-wide disturbance triggered by the tripping of multiple 330kV transmission lines and the disconnection of some generating units.
According to NISO data, load allocation to the 11 electricity distribution companies dropped to zero megawatts (MW) at about 1:00 pm, marking the first grid collapse of 2026.
In a statement issued after the incident, the operator said power generation fell to zero MW at approximately 12:40 pm, leading to a total outage across the interconnected power network.
“Preliminary operational reports indicate that the disturbance was associated with the simultaneous tripping of multiple 330kV transmission lines, alongside the disconnection of some grid-connected generating units,” NISO said.
“These events collectively contributed to the system collapse at the time indicated.”
The operator noted that restoration efforts commenced shortly after the outage, with electricity supply already restored to key cities, including Abuja and Lagos.
“Following the outage, system restoration activities commenced at about 13:15 hours, in accordance with established grid restoration and recovery procedures,” the statement said.
“As of the time of this update, electricity supply has been successfully restored to Abuja, Osogbo, Benin, Onitsha, Sakete, Jebba, Kainji, Shiroro and parts of Lagos, while restoration efforts are continuing progressively in other parts of the country.”
NISO added that a detailed investigation into the cause of the national grid collapse is ongoing, with full restoration and stabilisation of the grid remaining a top priority.
