The Nigerian Independent System Operator (NISO) has confirmed that Friday’s national grid collapse was caused by a system-wide disturbance triggered by the tripping of multiple 330 kV transmission lines and the disconnection of some power-generating units.
NISO added that efforts to restore electricity supply began shortly after the outage, in line with established grid restoration and recovery procedures.
It said power supply has since been restored to several locations, including Abuja and parts of Lagos, as well as Osogbo, Benin, Onitsha, Sakete, Jebba, Kainji and Shiroro, while work continues to reconnect other parts of the country.
The operator added that a detailed investigation into the cause of the collapse is ongoing, with full restoration and stabilisation of the national grid described as a top priority.
Data from the operator show that electricity load allocation to all 11 distribution companies fell to zero megawatts at about 1pm, marking the first national grid collapse recorded in 2026.
In a statement by the NISO, said power generation had earlier dropped to zero megawatts at around 12:40pm, leading to a total outage across the country’s interconnected transmission network.
According to the operator, preliminary operational reports indicate that the disturbance was linked to the simultaneous tripping of several 330 KV transmission lines, alongside the loss of some grid-connected generating units, events it said collectively caused the system collapse.
