Winter Power System Remains Stable with No Loadshedding Since May

South Africa's power system has remained stable throughout the 2025 winter season, with electricity being successfully delivered 97% of the time since April, according to Eskom's latest update.

Loadshedding-Free Winter Continues

The national power utility reports that South Africa has experienced no loadshedding since 15 May 2025, with only 26 hours of power cuts recorded between 1 April and 14 August 2025. This marks a significant improvement compared to previous years' winter performance.

With just over two weeks remaining in Eskom's designated Winter Outlook period, which ends on 31 August, the power system appears well-positioned to maintain this stability through the remainder of the season.

Current System Status

As of 15 August, unplanned outages stand at 10,538MW, while available generation capacity is 30,480MW against an expected evening peak demand of 27,969MW. This provides a comfortable buffer to meet both current demand and anticipated requirements over the weekend.

Eskom plans to return an additional 4,151MW of generation capacity to service ahead of Monday evening's peak and throughout the coming week, which will further enhance overall grid stability.

Performance Indicators Show Improvement

For the week of 8-14 August 2025, the Energy Availability Factor (EAF) ranged between 61% and 66%, with a month-to-date average of 64.65%. This excludes Kusile Unit 6, which has been supplying 720MW to the grid since March but hasn't yet reached commercial operation status.

The utility's use of expensive diesel-powered open-cycle gas turbines (OCGTs) has decreased significantly, with a load factor of just 1.21% this week, down from 5.99% in the previous week.

The Unplanned Capability Loss Factor (UCLF) decreased to 28.14% between 1 April and 14 August, showing a week-on-week improvement of approximately 0.21%. However, this figure remains about 2.2% higher than the same period last year.

Planned Maintenance Continues

Eskom conducted planned maintenance on an average of 5,193MW of capacity during the past week, representing about 11.09% of total generation capacity. This level of maintenance is similar to the previous week but shows a 0.8% increase compared to the same period last year.

The continued focus on maintenance while maintaining system stability suggests that Eskom's Generation Recovery Plan is yielding results, despite the year-to-date EAF of 60.3% being below last year's 63.15% for the same period.

Outlook: Remaining Winter Period and Beyond

Eskom's Winter Outlook, published in May, remains valid according to the utility. The plan indicated that loadshedding would not be necessary if unplanned outages stayed below 13,000MW – a threshold that has been maintained so far.

If unplanned outages were to rise 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. However, with current performance, this scenario appears unlikely.

Eskom is scheduled to announce its Summer Outlook in September 2025, which will provide projections for the upcoming warmer months when electricity demand typically decreases.

Concerns About Network Strain and Illegal Connections

Despite the improved generation performance, Eskom has raised concerns about network strain due to illegal connections and meter bypassing, particularly during the winter period when electricity usage increases.

The utility warns that these illegal activities can lead to transformer overloads, equipment damage, and extended outages in affected areas. To mitigate these risks, Eskom implements targeted load reduction in high-risk areas during peak hours.

Key Terms Explained

Energy Availability Factor (EAF): The percentage of total generation capacity that is available for dispatch. An EAF of 64.65% means that approximately two-thirds of Eskom's total generation capacity is available to produce electricity.

Unplanned Capability Loss Factor (UCLF): The percentage of generation capacity lost due to unexpected breakdowns or failures. At 28.14%, this means that more than a quarter of Eskom's generation capacity is offline due to unplanned issues.

Open-Cycle Gas Turbines (OCGTs): Quick-starting power plants that run on diesel fuel and are used during peak demand periods or emergencies. They are expensive to operate compared to coal or renewable energy sources. A load factor of 1.21% means these plants are running only about 1.2% of their potential operating time.

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

Gigawatt-hour (GWh): A unit of energy equal to one million kilowatt-hours. Eskom has generated 995.48GWh from OCGTs this financial year to date.