… frequency hits 51.67–49.03Hz, voltage swings 348–293kV
“We are losing money and damaging machines” – Ogaji calls for urgent reforms over inefficiencies
Oredola Adeola
The Association of Power Generation Companies (APGC) has raised serious concerns over ongoing instability in the national grid, warning that prolonged fluctuations in frequency, voltage, and generation output are putting critical generating equipment at risk.
This is sequel to the data obtained from NISO website showing grid code requirements for the February and March 2026.
According to data from March 13 and 14, 2026, the grid has experienced wide swings in both frequency and voltage, as well as significant changes in power output.
On March 13, the highest frequency recorded was 51.67 Hz and the lowest 49.03 Hz, while peak generation reached 4,123.30 MW and the lowest output was 3,480.67 MW. Voltage levels similarly fluctuated, with a high of 348 kV and a low of 304 kV.
The following day, March 14, the trend persisted. Frequency ranged between 50.77 Hz and 49.08 Hz, peak generation hit 4,130.70 MW, and the lowest output was 3,591.22 MW.
Voltage also experienced wider variation, spanning 346 kV to 293 kV, highlighting the ongoing strain on the system.
Dr. Joy Ogaji, CEO of APGC warned that turbines, generators, and other sensitive equipment are under heightened stress due to prolonged exposure to these deviations.
“The National Integrated System Operator (NISO) is essentially maintaining the grid by the grace of God, often at the expense of GenCos’ machines.”
Dr. Ogaji, stressed that the consequences of grid instability go far beyond technical disruptions, extending into significant financial and operational losses for generation companies.
According to her, “GenCos suffer immensely from the volatility of the national grid, as they lose money in the frequent start-ups and shutdowns, loss of gas, and increased maintenance costs.”
She explained that power generation systems are designed to operate within strict technical limits, warning that persistent deviations from these conditions undermine efficiency and reliability.
“It is international best practice that electrical equipment operates within set conditions for optimal performance. Any fluctuation outside these limits forces the machines to run at lower efficiency.”
Ogaji noted that thermal plants, particularly gas-fired turbines widely used in Nigeria, are most affected by unstable grid conditions.
“Gas turbines are designed to operate optimally at base load. When forced to operate far from these levels due to grid instability, efficiency drops significantly.”
She revealed that such inefficiencies come with measurable financial implications:
“Operating turbines away from their baseload can increase gas consumption by as much as 15 to 20 per cent—costs that are neither recognised by NBET nor captured under the current MYTO framework.”
Beyond efficiency losses, she warned of deeper mechanical consequences arising from persistent frequency and voltage fluctuations.
“Any frequency deviation beyond acceptable tolerance levels can lead to gradual or sudden damage to generating equipment, increasing maintenance requirements and shortening the lifespan of these machines.”
The APGC CEO further linked the issue directly to grid management challenges, stating that:
“The inability of the system operator to maintain grid stability within acceptable technical limits has exposed generator units to operate beyond their factory-rated capacity.”
She added that the repeated ramping up and down of turbines under unstable conditions is accelerating fatigue on critical components, driving up operations and maintenance (O&M) costs at a time when GenCos are already facing financial strain.
“These conditions subject turbines to thermal stress, irregular heating cycles, and wear on critical components, all of which increase maintenance costs and reduce operational life.”
Ogaji also highlighted structural constraints compounding the problem, particularly the difficulty in accessing foreign exchange required for major maintenance and inspections.
“There are overdue inspections and maintenance requirements which, if not addressed, could result in systemic breakdown of generation facilities.”
She warned that without urgent intervention, the situation could escalate beyond operational stress to a broader sectoral risk.
“If these challenges persist, it may result in a complete breakdown of the power generation subsector,” she disclosed.
Industry experts have highlighted that such fluctuations can accelerate wear and tear, increase operational costs, and reduce the lifespan of generation assets.
With power generation companies already operating under tight margins, the experts stated that sustained instability threatens not only equipment but also the reliability of electricity supply nationwide.
According to them, system-level insights suggest the issue may extend beyond operational management.
A source within NISO, who was not authorised to speak publicly, indicated that grid instability is increasingly being viewed as a systemic challenge rather than an isolated occurrence.
According to the source, the situation is being driven by persistent gas supply constraints, repeated forced shutdowns of generating units, and sustained pressure on grid management operations, pointing to deeper structural issues within the power sector.
While NISO has yet to issue an official statement on the specific March fluctuations, available system trends indicate that the grid continues to operate under tight conditions.
