PENGASSAN Strike: Nigeria’s National Grid Experiences Generation Shortfalls – NISO

Nigerian Independent System Operator (NISO) on Tuesday said the national grid experienced significant generation shortfalls due to industrial action by the Petroleum and Natural Gas Senior Staff Association of Nigeria (PENGASSAN).

NISO in a public notice by its management on Tuesday morning said the disruptions triggered widespread gas shortages, impacting power generation.


The system operator noted that available generation dropped from over 4,300 MW to about 3,200 MW at its lowest point due to gas supply disruptions.

“The Nigerian Independent System Operator (NISO) wishes to notify the public of recent major generation shortfalls on the National Grid, caused by industrial actions of the Petroleum and Natural Gas Senior Staff Association of Nigeria (PENGASSAN) within the gas supply chain.

“These disruptions triggered widespread gas shortages, reducing available generation from over 4,300 MW in the early hours of Sunday, 28th September 2025, to about 3,200 MW at the lowest point,” the statement said.

In response, NISO said it promptly deployed contingency measures to preserve the stability, security, and reliability of the national grid, including hydropower optimisation, generation dispatch, load balancing, voltage and frequency support, and demand-side management.

NISO said it strategically ramp-ups from major hydro stations, contributing over 400 MW of additional output to cushion the shortfall from gas-fired plants.

The system operator said it made real-time load adjustments to match available generation with system demand, while preventing a system frequency collapse.

It added that it continuously deployed reactive power compensation and reserve monitoring to safeguard system integrity.

“Selective load shedding, applied as a last resort, to avert a system-wide collapse and ensure fair power distribution.

“These timely actions enabled the NISO NCC to minimise the impact of the labour-induced gas shortages, sustain operational security, and maintain supply to critical loads, thereby averting a nationwide blackout,” it said.

The system operator reaffirmed its commitment to proactive grid management, operational excellence, and the application of best-in-class practices to guarantee a secure and reliable electricity supply for the nation.

NISO had on Sunday raised concerns about the potential impact of the dispute between PENGASSAN and Dangote Refinery on the nation’s power sector.

At the time, it said the national grid relies heavily on gas-fired generation, and any sustained disruption in gas supply could constrain generation capacity, affect system operations, and undermine the stability and reliability of electricity supply across the country.

NISO is in charge of electricity system operations, managing load allocation from generation companies to distribution companies and eligible customers.