The Nigerian Independent System Operator (NISO) said it has fully restored electricity supply to all parts of the country and the system stability has normalised.
NISO disclosed this in a statement signed by its management on Monday night.
The Independent System Operator said the national grid experienced a system disturbance at 2:01 p.m. on Monday, leading to a partial collapse.
On Monday, electricity distribution companies (DisCos) announced a power outage affecting their franchise areas. The DisCos said the outage was due to a loss of supply from the national grid, which occurred on Monday afternoon.
According to NISO, 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 Nigerian Independent System Operator (NISO) 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 that led to a partial collapse.
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“It would be recalled that the Lagos–Escravos-Lagos gas pipeline was vandalised on 10 December 2025 which led to the shortage in power generation in the country. This has further led to the fragility and weakness of the national grid,” the statement said.
However, it said, the Delta generation complex successfully operated on island mode at the 132kV sub-transmission voltage level.
This, it said, enabled the continued supply of electricity to Oghara, Amukpe, Benin, and Efunrun 132kV substations, with a total generation of 114 megawatts from four units at the Delta Thermal Power Station.
In line with established operational procedures, NISO said, it promptly initiated system response measures using its dispatch and monitoring tools at the National Control Centre (NCC), Osogbo.
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“Supply has been fully restored to all parts of the country and the system stability has normalised.
“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 reoccurrence of such major system incidents,” it said.
NISO reassured Nigerians of its continued commitment to proactive grid management and the application of best operational practices to ensure the stability and reliability of the national grid.
NISO is in charge of electricity system operations, managing load allocation from generation companies to distribution companies and eligible customers.
This latest disruption adds to a series that has raised concerns about the stability of Nigeria’s electricity system.
