Eight weeks in Eskom danger zone for power station breakdowns

Eskom reports that, as of Friday, the weekly average breakdowns at its power stations were 14,496 MW. For eight weeks in a row, average breakdowns have exceeded the power utility’s 13,000 MW “safe” threshold.

While the state-owned power utility reported substantial improvements in open-cycle gas turbine (OCGT) usage this week, capacity offline due to breakdowns remained stubbornly high.

Despite the high unplanned outages and icy weather conditions in parts of South Africa, Eskom said the power system remained stable and continues to show resilience in meeting the winter demand.

“While occasional system constraints do arise, they are effectively managed, with sufficient emergency reserves available and strategically deployed during morning and evening peak periods,” it said.

Eskom said its winter outlook, published on 5 May 2025, remains valid. The winter outlook stated that load-shedding would not be necessary if unplanned outages stay below 13,000 MW.

However, if outages rise to 15,000 MW, stage 2 load-shedding would be probable, albeit limited to a maximum of 21 days out of 153 days.

Eskom’s unplanned outages averaged 14,496 MW over the last week, well above the 13,000 MW warning level and 1,942 MW higher compared to the same period last year.

The year-to-date average for unplanned outages was 14,091 MW. However, Eskom said this increase was primarily due to technical adjustments rather than a decline in operational performance.

“Medupi Unit 4, 800MW capacity, was added to the unplanned outage figures from 1 June 2025, having previously been excluded due to its long-term offline status,” Eskom stated.

Eskom said unplanned outages are currently being managed within acceptable levels and that 2,350 MW of capacity was scheduled to return to service by Monday.

In recent weeks, Eskom has reduced the amount of scheduled maintenance conducted on power plants to ensure sufficient capacity to meet demand.

During the week of 27 June to 3 July, planned maintenance averaged 3,528 MW. The Energy Availability Factor (EAF) ranged from 61% to 64%, with a month-to-date average increase to 63.29%.

EAF is a measure of generating capacity available from Eskom power plants relative to their installed capacity. It takes breakdowns and maintenance into account.

The Unplanned Capability Loss Factor (UCLF), which measures the capacity lost due to breakdowns, was 29.74% for the financial year to date (1 April to 3 July 2025). This was higher than the 27.17% UCLF during the same period last year.

Eskom diesel usage

Another important indicator of whether there is a danger of load-shedding is Eskom’s open-cycle gas turbine (OCGT) load factor.

OCGTs are diesel-powered stations that Eskom uses to help balance the grid and as emergency generation units to keep load-shedding at bay.

The year-to-date load factor for OCGTs declined to 10.70%. However, this figure remains higher than the 6.12% recorded during the same period last year. The weekly OCGT load factor declined from 7.25% to 2.41%.

“Although diesel usage is within budget, it is expected to decline as more units return to service from long-term repairs and maintenance activities are reduced, increasing available generation capacity,” Eskom said.

Year-to-date, Eskom spent approximately R4.85 billion on fuel for the OCGT fleet, generating 824.08 GWh. This is higher than the 471.18 GWh generated during the same period last year.

Eskom reported that its year-to-date EAF has declined to 58.21% and remains lower than the 61.39% recorded during the same period last year, primarily due to an increase in breakdowns.