Eskom right on the edge

Eskom’s latest performance data shows that it is right on the edge of implementing load shedding based on its 2025 winter outlook.

On 5 May 2025, Eskom shared its Winter Outlook, which covers the period from 1 May 2025 to 31 August 2025, with the South African public.

This outlook suggests that load shedding will not be necessary if unplanned outages remain below 13,000 MW.

If outages reach 15,000 MW, load shedding would be limited to a maximum of 21 days out of 153 days and restricted to Stage 2.

Eskom also set an energy availability factor (EAF) target of 70% by March 2025, which it said would mean the end of load shedding.

“The target is to reach a 70% EAF by March 2025, which will not only ensure a stable energy supply but also reduce diesel expenditure,” Eskom said.

On Friday, 30 May 2025, Eskom stated that the power system remains stable and continues to demonstrate resilience.

“System constraints remain, and adequate emergency reserves are in place and strategically deployed to support demand during the morning and evening peak winter periods,” it said.

While there is no load shedding, Eskom is operating on the edge, as unplanned outages exceed the 13,000 MW Winter Outlook threshold.

From 23 to 29 May 2025, unplanned outages averaged 13,871 MW, representing an increase of 883 MW compared to the same period last year and 871 MW above Eskom’s base case.

For the financial year to date, from 1 April 2025 to 29 May 2025, the average unplanned outages stand at 13,600 MW.

The Unplanned Capacity Loss Factor (UCLF), which measures the capacity lost due to unplanned outages, stands at 28.60% for the financial year to date.

This represents an increase of 0.2% compared to 28.43% recorded over the same period last year. The increase is primarily due to delays in returning units from planned maintenance.

Eskom explained that outage slips are the main driver of fluctuations in unplanned outages at its power stations.

These outage slips occur when a unit initially scheduled for planned maintenance is reclassified as unplanned due to exceeding the scheduled maintenance timeframe.

The year-to-date EAF is 57.67%, compared to 60.45% over the same period last year. This decline is primarily due to a 2.6% increase in planned maintenance.

This is well below Eskom’s March 2025 target of 70% EAF, which is why load shedding remains a reality in South Africa.

The high unplanned outages, which caused Eskom to miss its EAF targets, mean that the power utility must spend billions on its Open-Cycle Gas Turbine (OCGT) to keep the lights on.

Year-to-date, Eskom spent approximately R3.54 billion on fuel for the OCGT fleet, generating 595.33 GWh. This is higher than the 219.37 GWh generated during the same period last year.

The year-to-date OCGT load factor stands at 12.31%, higher than the 4.54% recorded during the same period last year.

The charts below show Eskom’s energy availability factor (EAF), unplanned outages, and OCGT usage.