Electricity supply has been restored across Nigeria following a system disturbance that caused a partial collapse of the national power grid on Monday, according to the Nigerian Independent System Operator.

NISO confirmed the restoration in a statement issued in Abuja, stating that the grid has stabilised and electricity supply has been normalised in all parts of the country.

The system operator disclosed that the disturbance occurred at about 2:01 pm on Monday, resulting in widespread power outages before restoration efforts were successfully concluded.

“We wish to inform the general public and relevant stakeholders that the national grid experienced a system disturbance at 2.01pm on Monday, that led to a partial collapse,” NISO stated.

According to the operator, investigations are still ongoing to establish the exact cause and sequence of events that triggered the system disturbance.

“Investigations into the cause and sequence of events leading to the system disturbance are currently ongoing, and appropriate measures shall be put in place to forestall future reoccurrence of such major system incidents,” the statement said.

NISO attributed the fragility of the national grid to earlier challenges in power generation arising from gas supply constraints, recalling the vandalisation of the Lagos–Escravos–Lagos gas pipeline on December 10.

“It would be recalled that the Lagos–Escravos–Lagos gas pipeline was vandalised on December 10, 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 operator noted.

The system operator said preliminary findings revealed that the disturbance involved the tripping of several power generation units and critical 330 kilovolt transmission lines, leading to power outages across many parts of the country.

NISO, however, noted that the Delta generation complex was able to operate independently during the incident, thereby limiting the impact in some areas.

“The Delta generation complex successfully operated on island mode at the 132kV sub-transmission voltage level. This 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,” NISO explained.

The operator added that restoration efforts were promptly initiated from the National Control Centre in Osogbo, using established dispatch and monitoring procedures.

In its assurance to Nigerians, NISO stated that it remains committed to effective grid management and improved operational practices to ensure a more stable and reliable electricity supply across the country.