- The 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.
To further enhance grid stability, Eskom plans to return a total of 2 730MW of generation capacity to service ahead of the evening peak on Monday, 23 June 2025.
During the week of 13 to 19 June, planned maintenance averaged at 3 659MW, resulting in a decline in planned outages. During the same period, the Energy Availability Factor (EAF) ranged from 60% to 63%, with a month-to-date average of 60.48%.
Eskom reports that their Unplanned Capacity Loss Factor (UCLF), which measures the capacity lost due to unplanned outages, stands at 29.23% for the financial year to date (1 April to 19 June 2025). This marks a slight increase of approximately 1.7% compared to 27.51% during the same period last year. The rise in unplanned outages is partly attributed to delays in returning units from planned maintenance amounting to ~1 300MW, including 800MW from Medupi Unit 4 since 1 June 2025.
Respected energy analyst, Chris Yelland, highlights that “the unplanned outages are at 30.73% which are now 6 percentage points higher than for the same time last year. So even with planned maintenance now dropping below 2023 and 2024 levels for the same period, the EAF remains stubbornly low at around 60%, 2 percentage points below that for the same time in 2024.”
The latest Eskom week-on-week energy availability factor EAF for 2025. Data source: Eskom. Image credit: Chris Yelland. Chris is an energy analyst, consultant, electrical engineer, public speaker, writer and MD at EE Business Intelligence (Pty) Ltd. Follow Chris on X – @chrisyelland
Link to Eskom’s real time performance data portal HERE
As of today, Eskom reports unplanned outages amount to 12 892MW, while the available generation capacity stands at 31 681MW, excluding the 720MW contribution from Kusile Unit 6, which is not yet in commercial operation. This capacity is sufficient to meet the projected peak demand for tonight, which is expected to reach 28 425MW.
The year-to-date open-cycle gas turbine (OCGT) load factor stands at 11.73%, representing a 0.25% decrease from the previous week. This is higher than the 5.78% 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:
- From 13 to 19 June 2025, the average level of unplanned outages reached 15 076MW, exceeding last year’s figure for the same period by 3 144MW and surpassing the base case estimate of 13 000MW by 2 076MW. This increase is largely due to delays in restoring Medupi Unit 4 (800MW), which is undergoing a long-term recovery project, and Tutuka Unit 1 (585MW). Year-to-date, the average unplanned outages stand at 13 966MW.
- For the financial year-to-date, planned maintenance has averaged at 5 629MW, representing 11.99% of total generation capacity. This reflects a decrease from the previous week, but a 1.12% increase compared to the same period last year.
- The year-to-date EAF has also shown an upward trend, reaching 58.25%. However, this still represents a 2.83% decline compared to the 61.08% recorded during the same period last year. The decrease is largely due to a 1.12% year-on-year increase in planned maintenance. It is important to note that these EAF figures exclude the 720MW from Kusile Unit 6, which, although not yet commercially operational, is already contributing to the national grid.
- Year-to-date, Eskom spent approximately R4.51 billion on fuel for the OCGT fleet, generating 768.64GWh. This is higher than the 378.75GWh generated during the same period last year.
- The diesel expenditure is still within budget for the current financial year.
- The OCGT load factor decreased to 9.12% this week, compared to 14.79% in the previous week (6 to 12 June 2025).
Author: Bryan Groenendaal
