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By Daniel Adaji
Nigeria’s power sector operators on Monday offered different explanations for the nationwide electricity outage that followed a grid disturbance in the early afternoon.
The Nigerian Independent System Operator (NISO) attributed the incident to a partial grid collapse worsened by gas supply constraints, while electricity distribution companies cited a system collapse or disturbance.
The outage occurred around 14:01 hours on Monday, affecting electricity supply across several parts of the country.
In a statement, NISO said the national grid “experienced a system disturbance at 14:01 hours on Monday, 29 December 2025 that led to a partial collapse.”
According to the system operator, the incident was linked to existing weaknesses in the grid following the vandalization of the Lagos–Escravos–Lagos gas pipeline on 10 December 2025, which reduced power generation nationwide.
NISO explained that the disturbance involved “the tripping of several generating units and critical 330kV transmission lines,” resulting in widespread supply disruptions.
However, Eko Electricity Distribution Company (EKEDC) described the event differently, informing customers that “there was a system collapse at 14:01hrs which has resulted to a loss of power supply across our network.”
The company said it was “working with our partners as we hope for the speedy restoration of the grid.”
Similarly, Abuja Electricity Distribution Company (AEDC) told customers that “a system disturbance occurred on the national grid at 14:02 pm today causing power outage across our franchise areas,” adding that it was coordinating with stakeholders to restore supply once the grid stabilised.
Despite the disruption, NISO said part of the system remained operational. The Delta generation complex, it noted, successfully ran on island mode at the 132kV sub-transmission level, supplying electricity to Oghara, Amukpe, Benin and Efunrun substations. A total of 114 megawatts was generated from four units at the Delta Thermal Power Station during the period.
NISO said it activated emergency response measures through its National Control Centre in Osogbo, using dispatch and monitoring tools in line with established operational procedures. The operator added that electricity supply has since been fully restored nationwide and system stability normalised.
While the DisCos focused on immediate service restoration, NISO said investigations into “the cause and sequence of events leading to the system disturbance are currently ongoing,” assuring that measures would be put in place to prevent a recurrence.
The system operator reaffirmed its commitment to proactive grid management and best operational practices, even as the differing accounts from NISO and the distribution companies highlighted ongoing communication gaps during major grid incidents.