Power System Holds Steady Despite Winter Pressure; No Loadshedding Expected

14 June 2025

South Africa's power system remains stable despite increasing pressure from winter demand, with Eskom confirming sufficient supply through the upcoming long weekend. The utility plans to return 3,170MW of generation capacity before Tuesday evening's peak to further strengthen grid resilience.

Grid Performance Under Winter Pressure

As South Africa moves deeper into winter, the power system is demonstrating resilience against rising electricity demand driven by colder temperatures. Eskom reports that while occasional constraints do occur, adequate emergency reserves are being strategically deployed during morning and evening peak periods.

The Energy Availability Factor (EAF) has been recovering as the utility moves beyond peak maintenance season, now fluctuating between 60% and 64%. Month-to-date, the EAF has increased to 60.56%, reflecting additional generation units returning from maintenance.

"The improving EAF figures are encouraging, but they still remain below the levels needed for long-term stability," notes our energy analyst team. "At 60.56%, we're seeing recovery, but this is still below the same period last year."

Maintenance Progress and Challenges

For the financial year-to-date, planned maintenance has averaged 5,793MW, representing 12.36% of total generation capacity. This marks a 1.6% increase compared to the same period last year, reflecting Eskom's ongoing efforts to address aging infrastructure.

However, unplanned outages continue to pose challenges. The Unplanned Capacity Loss Factor (UCLF) stands at 29.05% for the financial year to date (1 April to 12 June 2025), a slight increase of approximately 1.3% compared to the 27.79% during the same period last year.

From 6 to 12 June 2025, unplanned outages averaged 14,738MW, which is 1,738MW above Eskom's base case target of 13,000MW. This increase is largely attributed to maintenance delays, including 800MW from Medupi Unit 4, which has been delayed since 1 June 2025.

Winter Outlook Remains Cautiously Positive

According to Eskom's Winter Outlook (published 5 May 2025), loadshedding is not expected to be necessary through 31 August 2025 if unplanned outages stay below 13,000MW. However, if outages increase to 15,000MW, loadshedding would be limited to a maximum of 21 days out of the 153-day winter period and restricted to Stage 2.

Currently, unplanned outages are hovering above the critical threshold at 14,738MW for the past week, placing the system in a precarious position should additional units fail.

Diesel usage, which has been a significant expense in maintaining grid stability, is expected to decline as more units return from long-term repairs. However, the Open-Cycle Gas Turbine (OCGT) load factor increased to 14.79% this week, compared to 6.31% in the previous week, indicating heavier reliance on these emergency generation resources.

Call to Protect Infrastructure

With electricity demand rising during winter, Eskom has issued a warning about the dangers of illegal connections and energy theft, which often lead to transformer overloads and equipment failures. These incidents can cause extended outages and necessitate load reduction to protect the network.

The utility encourages the public to report illegal activities to the Eskom Crime Line at 0800 112 722 or via WhatsApp on 081 333 3323.

Key Terms Explained

Energy Availability Factor (EAF): The percentage of maximum energy generation that a plant is capable of supplying to the electrical grid, reduced by planned and unplanned outages. Higher percentages indicate better performance. Eskom targets 70% for stable supply.

Planned Capability Loss Factor (PCLF): The percentage of energy generation lost due to planned maintenance activities. While causing short-term reduction in capacity, planned maintenance is essential for long-term reliability.

Unplanned Capacity Loss Factor (UCLF): The percentage of potential energy generation lost due to unexpected breakdowns and failures. This is the most problematic metric as it represents unpredictable losses.

Open-Cycle Gas Turbines (OCGTs): Emergency power generation units that run on diesel. These are expensive to operate but provide quick-response capacity during peak demand or when other generation units are unavailable.

Megawatt (MW): A unit of power. For context, 1MW can power approximately 650 average South African homes.