Power supply has been restored across Africa’s most populous nation following the collapse of Nigeria’s national electricity grid on Monday afternoon, the Nigerian Independent System Operator (NISO) has confirmed.
The incident occurred at exactly 2:01 p.m. on Monday, December 29, 2025, disrupting electricity supply across several parts of the country.
Power generation had peaked at about 4,800 megawatts earlier in the day before plunging to 139 megawatts by 3:00 p.m., according to data obtained by our correspondent.
In a statement signed by its management on Monday night, NISO said the disturbance triggered the tripping of multiple power generation units and critical 330-kilovolt transmission lines, worsening the already fragile state of the national grid.
“The Nigerian Independent System Operator wishes to inform the general public and relevant stakeholders that the national grid experienced a system disturbance at 14:01 hours on Monday, 29 December 2025, which led to a partial collapse,” the statement said.
“Preliminary reports indicate that the disturbance involved the tripping of several generating units and critical 330kV transmission lines, resulting in a widespread impact on electricity supply across parts of the country.”
The latest grid incident comes against the backdrop of gas supply challenges following the vandalisation of the Escravos–Lagos gas pipeline on December 10, 2025, which significantly reduced gas availability to thermal power plants.
The pipeline damage led to widespread power shortages, forcing several generation companies to cut output and exposing long-standing structural weaknesses in the national grid. NISO noted that the gas constraints further weakened the system, making it more vulnerable to disturbances.
“This has further contributed to the fragility and weakness of the national grid,” the operator said.
Despite the disruption, NISO disclosed that the Delta generation complex successfully isolated itself from the national grid and continued operations in island mode at the 132kV sub-transmission voltage level. This intervention ensured uninterrupted power supply to Oghara, Amukpe, Benin, and Efunrun 132kV substations.
“A total generation of 114 megawatts was delivered from four units at the Delta Thermal Power Station,” NISO stated.
The system operator added that it promptly activated emergency response measures in line with established operational procedures, using its dispatch and monitoring tools at the National Control Centre in Osogbo.
NISO confirmed that electricity supply has now been fully restored nationwide, with system stability normalised after hours of coordinated recovery efforts.
“Supply has been fully restored to all parts of the country, and system stability has been normalised,” the statement said.
The operator also disclosed that investigations are ongoing to determine the precise cause and sequence of events that led to the partial collapse, assuring Nigerians that corrective measures would be implemented to prevent a recurrence.
“Investigations into the cause and sequence of events leading to the system disturbance are currently ongoing. Appropriate measures shall be put in place to forestall future recurrence of such major system incidents,” NISO assured.
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