Why national grid collapsed on Friday — NISO

The Nigerian Independent System Operator (NISO) has explained that Friday’s national electricity grid collapse was caused by the simultaneous tripping of several 330kV transmission lines, along with the disconnection of some power generation units.

The incident led to a sharp drop in electricity generation, which fell from over 4,500 megawatts to about 24 megawatts by around 1:30 pm. All 23 power plants connected to the grid reportedly lost output, leaving the country’s 11 electricity distribution companies with zero power allocation.

In a preliminary statement issued on Saturday, NISO said the system-wide disturbance occurred at approximately 12:40 pm on Friday, January 23, 2026, resulting in a total outage across the interconnected power network.

According to the operator, initial operational findings showed that the collapse was linked to the simultaneous tripping of multiple 330kV transmission lines and the shutdown of some grid-connected generating units, which together triggered the system failure.

NISO said restoration efforts began shortly after the outage, with grid recovery activities commencing around 1:15 pm in line with established restoration procedures.

The operator added that electricity supply had since been restored to areas including Abuja, Osogbo, Benin, Onitsha, Sakete, Jebba, Kainji, Shiroro, and parts of Lagos, while work continued to restore power in other parts of the country.

NISO also confirmed that an investigation into the incident is underway to determine the root and contributing causes, stressing that full restoration and stabilisation of the national grid remain its top operational priority.