Electricity supply has been restored across the country following Monday’s partial collapse of the national grid, with the Nigerian Independent System Operator (NISO) earning commendation for its prompt and coordinated response to the incident.
The system disturbance, which occurred at exactly 2:01 p.m. on Monday, December 29, 2025, led to a temporary disruption of power supply in several parts of the country. Data indicated that national power generation, which had peaked at about 4,800 megawatts earlier in the day, dropped sharply to 139 megawatts by about 3:00 p.m.
In a statement issued Monday night, NISO said the disturbance triggered the tripping of multiple power generation units and critical 330kV transmission lines, compounding the fragility of the national grid.
Despite the scale of the setback, the operator said it swiftly activated emergency response measures in line with established operational procedures.
A key highlight of the recovery effort was the successful isolation of the Delta generation complex, which continued operations in island mode at the 132kV sub-transmission level. This ensured uninterrupted electricity supply to Oghara, Amukpe, Benin and Efunrun substations, with a total of 114 megawatts delivered from four units at the Delta Thermal Power Station.
NISO attributed the grid’s vulnerability in part to lingering gas supply challenges arising from the vandalisation of the Escravos–Lagos gas pipeline earlier in December, which constrained thermal generation nationwide.
However, the operator said hours of coordinated system recovery efforts restored supply fully and normalised grid stability across the country.
Investigations into the precise cause of the disturbance are ongoing, NISO said, assuring that corrective measures would be implemented to prevent a recurrence.
Reaffirming its commitment to proactive grid management, NISO pledged continued application of best operational practices to ensure a stable and reliable national electricity supply, underscoring its growing role in strengthening confidence in Nigeria’s power system.
