- South Africa’s state owned power utility, Eskom, reports that the power system remains stable and continues to demonstrate resilience in response to increased electricity demand as a result of the cold snap.
- 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.
To further enhance grid stability, Eskom plans to return a total of 2 450MW of generation capacity to service ahead of the evening peak on Monday, 30 June 2025.
During the week of 20 to 26 June, planned maintenance averaged at 3 789MW, resulting in a further decline in planned outages. During the same period, the Energy Availability Factor (EAF) ranged from 60% to 64%, with a month-to-date average of 60.61%.
The Unplanned Capability Loss Factor (UCLF), which measures the capacity lost due to unplanned outages, stands at 29.36% for the financial year to date (1 April to 26 June 2025). This marks an increase of approximately 2.1% compared to 27.25% during the same period last year. The rise in unplanned outages is partly attributed to delays in returning units from planned maintenance amounting to ~995MW, including 800MW from Medupi Unit 4 since 1 June 2025.
In Eskom’s Winter 2025 Outlook released last month, the utility warned that if breakdowns, also known as the unplanned capacity loss factor (UCLF), exceeds 15000 MW, then loadshedding would be implemented and the country will face a maximum of 21 days out of 153 days at Stage 2.
As of today, unplanned outages amount to 15 137MW, which includes 800MW from the delayed Medupi Unit 4. The available generation capacity stands at 30 703MW, excluding the 720MW from Kusile Unit 6. Although Kusile Unit 6 has not yet entered commercial operation, it has been contributing to the grid since 23 March 2025. With this combined capacity, Eskom is well-positioned to meet tonight’s anticipated peak demand of 28 810MW.
The year-to-date load factor for open-cycle gas turbines (OCGTs) has declined to 11.37%, reflecting a 0.36% decline compared to the previous week. Despite the decrease, this figure remains higher than the 6.21% recorded during the same period last year.
Diesel usage is expected to decline as more units return to service from long-term repairs and maintenance activities are reduced, increasing available generation capacity.
The Winter Outlook, published on 5 May 2025, covering the period ending 31 August 2025, remains valid. It indicates that loadshedding will not be necessary if unplanned outages stay below 13 000MW. If outages rise to 15 000MW, loadshedding would be limited to a maximum of 21 days out of 153 days and restricted to Stage 2.
Key Performance Highlights:
- For the week of 20 to 26 June 2025, unplanned outages averaged 14 696MW, exceeding last year’s figure by 2 815MW and the base case estimate of 13 000MW by 1 696MW. The increase is largely due to Medupi Unit 4, which has been offline since August 2021 and was scheduled to return on 30 May 2025. The delay in its return was factored into the unplanned outage calculations from 1 June 2025, adding 800MW. Year-to-date, average unplanned outages stand at 14 031MW.
- For the financial year-to-date, planned maintenance has averaged at 5 481MW, representing 11.67% of total generation capacity. This reflects a decrease from the previous week, but a 0.7% increase compared to the same period last year.
- The year-to-date Energy Availability Factor (EAF) has shown an upward trend, reaching 58.47%. However, this is still lower than the 61.19% recorded during the same period last year, primarily due to a 2.1% year-on-year increase in unplanned maintenance. It is important to note that the EAF figure exclude the 720MW contribution from Kusile Unit 6, which, although not yet commercially operational, has been supplying power to the national grid since 23 March 2025.
- Year-to-date, Eskom spent approximately R4.76 billion on fuel for the OCGT fleet, generating 810.24GWh. This is higher than the 442.65GWh generated during the same period last year.
- The diesel expenditure is still within budget for the current financial year.
- The open-cycle gas turbine (OCGT) load factor declined further this week, reaching 7.25%, down from 9.12% recorded during the previous week (13 to 19 June 2025).
Source: Eskom
