Eskom load-shedding danger

Eskom’s breakdowns averaged 15,076 MW over the last week, well above its base case of 13,000 MW for the 2025 winter period.

This was revealed in an Eskom system update late on Friday, 20 June 2025, in which the power utility reported its latest performance data.

Eskom said its power system remains stable and continues to demonstrate resilience in response to increased electricity demand.

“While occasional system constraints are experienced and managed, sufficient emergency reserves are in place and are strategically deployed to support demand during morning and evening peak periods,” Eskom said.

Eskom previously said it would not need to implement load-shedding over the winter if its unplanned outages remained below 13,000 MW of capacity.

It forecast that 15,000 MW of unplanned outages would lead to stage 2 load-shedding. Eskom’s weekly data showed that it frequently exceeded that level in recent weeks.

In addition to Eskom’s update on Friday indicating that it was in danger of needing to implement load-shedding, its other weekly data also painted a concerning picture.

Eskom’s data portal showed that its weekly unplanned and “other” outages stood at more than 14,800 MW for 57% of the time from 11 to 17 June 2025, up from 21% the week before.

In addition, the percentage of time during which unplanned outages exceeded 15,200MW increased from 9% to 34%.

Despite Eskom’s fleet clearly being in a worse state than last year, the power utility’s latest 52-week outlook is much more positive than the same one from 2024.

The power utility’s saving grace in 2025 could be the reduction in demand of more than 1,000MW — equivalent to one stage of load-shedding.

For example, in week 25 of 2025, Eskom is only expecting residual demand to reach 30,036MW, compared with 31,271MW in the same week last year.

Had the power utility’s electricity demand been similar to last year, it would likely already have needed to implement load-shedding.

Eskom’s latest data showed that from 6 to 12 June 2025, unplanned outages averaged 3,144 MW higher compared to the same period last year.

It is 2,076 MW above Eskom’s base case of 13,000 MW and exceeds the 15,000 MW threshold, meaning South Africa is in stage 2 load-shedding territory.

For the financial year to date, from 1 April 2025 to 19 June 2025, the average unplanned outages stand at 13,966 MW.

The Unplanned Capacity Loss Factor (UCLF), which measures the capacity lost due to unplanned outages, stands at 29.23% for the financial year to date.

This represents an increase of 1.7% compared to 27.51% recorded over the same period last year.

Eskom explained that the increase in unplanned outages is primarily driven by outage slips at its coal-fired power stations.

“This increase is largely due to delays in restoring Medupi Unit 4 (800 MW), which is undergoing a long-term recovery project and Tutuka Unit 1 (585 MW),” it said.

Year-to-date, Eskom spent approximately R4.51 billion on fuel for the OCGT fleet, generating 768.64 GWh. This is higher than the 378.75 GWh generated during the same period last year.

Open-cycle gas turbines (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 diesel expenditure is still within budget for the current financial year,” said Eskom.

“The OCGT load factor decreased to 9.12% this week, compared to 14.79% in the previous week from 6 to 12 June 2025.”

Eskom plans to return 2,730 MW of generation capacity to service ahead of the evening peak on Monday, 23 June 2025, which it said would enhance grid stability.