Why national grid collapsed — NISO

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

PUNCH Online had reported that the national electricity grid collapsed on Friday, forcing power generation to crash from over 4,500 megawatts to about 24MW by around 1:30pm. The incident affected all 23 power plants connected to the grid, leading to zero electricity allocation to the country’s 11 distribution companies.

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

According to the operator, initial operational findings indicated that the outage was linked to the tripping of multiple high-voltage transmission lines and the shutdown of some grid-connected generating units, which together triggered the collapse.

NISO noted that restoration efforts began shortly after the incident.

“System restoration activities commenced at approximately 13:15 hours in line with established grid recovery procedures,” the statement said.

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

NISO also confirmed that an investigation into the incident was underway to determine its root and contributory causes, stressing that full restoration and stabilisation of the grid remained a top priority.