Power System Stability Continues, No Loadshedding Since Mid-May

25 July 2025

South Africa's power system continues to operate without loadshedding, with Eskom reporting that the grid remains stable as it effectively manages winter electricity demand.

Loadshedding Suspension Continues

According to Eskom's latest update, no loadshedding has been implemented since 15 May 2025 – marking 71 consecutive days without power cuts. For the entire period between 1 April and 24 July 2025, only 26 hours of loadshedding have been recorded, representing a significant improvement in system stability.

With 37 days remaining in Eskom's Winter Outlook period, which ends on 31 August 2025, the utility appears confident in its ability to maintain this stability through the remainder of winter.

Current System Performance

As of 25 July 2025, unplanned outages stand at 11,695MW, while available generation capacity is 30,236MW. Today's peak electricity demand is expected to reach 27,715MW, leaving a margin of approximately 2,500MW.

For the week of 18-24 July 2025, planned maintenance averaged 5,050MW, while the Energy Availability Factor (EAF) ranged between 62% and 66%. The month-to-date EAF average has increased to 63.11%.

In a move to further strengthen grid stability, Eskom has announced plans to return 3,960MW of generation capacity to service ahead of Monday evening's peak (28 July 2025) and throughout the coming week.

Performance Metrics Show Mixed Results

Between 1 April and 24 July 2025, the Unplanned Capability Loss Factor (UCLF) decreased to 28.99%. While this represents a slight improvement of approximately 0.5% compared to the previous week, it remains about 2.4% higher than the 26.60% recorded during the same period last year.

The utility notes that as of 24 July 2025, the UCLF stood at 23.79%, suggesting recent performance is better than the period average.

The year-to-date EAF stands at 59.42% (excluding Kusile Unit 6's contribution), which is below the 62.42% recorded during the same period last year. This underperformance is primarily attributed to the 2.4% increase in unplanned maintenance compared to 2024.

Reduced Reliance on Emergency Generation

The open-cycle gas turbine (OCGT) load factor decreased to 1.86% this week, down significantly from 8.6% recorded during the previous week (11-17 July 2025). This indicates less reliance on these expensive emergency generators.

However, for the period from 1 April to 24 July 2025, Eskom has spent R5.616 billion on fuel for its OCGT plants, generating 952.41GWh of electricity. This output remains higher than the 493.16GWh generated during the same timeframe last year, suggesting overall higher usage of these emergency reserves in 2025 despite recent reductions.

Eskom also issued a correction regarding previously reported diesel spend figures, noting that the R5.897 billion reported for the week ending 17 July should have been R5.554 billion.

Winter Outlook Remains Unchanged

Eskom's Winter Outlook, which covers the period until 31 August 2025, remains valid. According to this outlook, loadshedding will not be necessary if unplanned outages stay below 13,000MW. Should outages 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.

With current unplanned outages at 11,695MW, the system remains within the parameters for avoiding loadshedding.

Call to Prevent Illegal Connections

Eskom has issued a warning about the strain placed on the network by illegal connections and meter bypassing, particularly during winter when electricity demand rises. These unauthorized connections can lead to transformer overloads, equipment damage, and extended outages in affected areas.

The utility noted that in high-risk areas, it may implement load reduction during peak hours to prevent equipment damage, even while national loadshedding remains suspended.

Outlook

Based on the current data, Eskom appears well-positioned to maintain loadshedding-free operations through the remainder of winter, provided unplanned outages remain below the critical 13,000MW threshold. The planned return of 3,960MW of generation capacity by Monday will further strengthen the system's resilience.

However, the elevated UCLF compared to last year and continued high spending on emergency generation suggest that underlying system challenges persist despite the positive short-term outlook. The coming weeks will be critical as South Africa navigates the final stretch of the winter demand period.

Eskom will provide its next scheduled update on Friday, 1 August 2025.

Key Terms Explained

Energy Availability Factor (EAF): The percentage of maximum energy generation that a plant is capable of supplying to the electrical grid, taking into account both planned and unplanned outages. A higher percentage indicates better performance. For context, Eskom targets an EAF of 70% but has struggled to exceed 60% in recent years.

Unplanned Capability Loss Factor (UCLF): The percentage of generating capacity lost due to unplanned events or breakdowns. This includes boiler tube leaks, turbine problems, or other unexpected failures. Lower percentages indicate better reliability. For perspective, international best practice for similar coal fleets is around 10-15%.

Open-Cycle Gas Turbines (OCGTs): Emergency power generators that run on diesel fuel. While they can be started quickly to meet peak demand or during emergencies, they are extremely expensive to operate - costing approximately 4-5 times more per unit of electricity than coal generation. Eskom uses them as a last resort to prevent or minimize loadshedding.

Planned Maintenance: Scheduled downtime for power plants to undergo repairs and preventative maintenance. Measured in megawatts (MW), it represents capacity temporarily unavailable by design. Adequate planned maintenance is essential for long-term plant health and reliability.

Load Reduction: A targeted power interruption in specific areas with high rates of illegal connections to prevent transformer and equipment damage. Unlike loadshedding, which is implemented nationally to balance supply and demand, load reduction targets specific high-risk areas.

Winter Outlook: Eskom's forecast for power system performance during the high-demand winter months (typically May through August). It provides scenarios based on different levels of plant performance and outages.