18 July 2025

Unplanned Outages Drop to 10,846MW as Eskom Maintains Power Stability Since Mid-May

South Africa's power system continues to demonstrate resilience with unplanned outages decreasing to 10,846MW as of 18 July 2025. Eskom reports that no loadshedding has occurred since 15 May 2025, with only 26 hours of power cuts recorded between 1 April and 17 July 2025 – a significant improvement compared to daily outages experienced during the same period last year.

Current System Performance

Available generation capacity currently stands at 31,818MW, comfortably exceeding tonight's expected electricity demand of 28,215MW. The utility appears well-positioned to meet both today's demand and anticipated requirements over the weekend.

The Energy Availability Factor (EAF) has shown steady improvement, ranging between 60% and 65% during the week of 11-17 July, with the month-to-date average increasing to 62.31%. This represents a significant recovery from the sub-50% levels seen in 2023, though still below the 61.97% recorded during the same period last year.

Eskom plans to further strengthen grid stability by returning 3,330MW of generation capacity to service ahead of Monday evening's peak (21 July 2025) and throughout the coming week.

Reduced Reliance on Emergency Resources

The utility reports a 48.4% reduction in diesel consumption compared to the same period in FY24, with spending remaining within budget allocations for the April-July period. This reduced reliance on expensive emergency generation is a positive indicator of improved system performance.

The load factor for Open-Cycle Gas Turbines (OCGTs) decreased to 8.60% this week, down from 11.92% in the previous week, indicating less dependency on these emergency resources. However, the year-to-date OCGT load factor of 10.64% remains higher than the 5.55% recorded during the same period last year, suggesting occasional system constraints that require strategic deployment of emergency reserves during morning and evening peaks.

Maintenance and Outage Trends

For the week of 11-17 July 2025, planned maintenance averaged 4,467MW. While this represents a decrease from previous weeks, the financial year-to-date planned maintenance has averaged 5,229MW (11.13% of total generation capacity) – a 0.8% increase compared to the same period last year, indicating Eskom's continued focus on essential maintenance work.

The Unplanned Capability Loss Factor (UCLF) – which indicates the percentage of generation capacity lost due to unexpected outages – stood at 29.53% between 1 April and 17 July 2025. This is approximately 2.6% higher than the 26.95% recorded during the same period last year. However, the current UCLF has improved to 23.35%, reflecting better recent performance.

Winter Outlook Remains Positive

With 44 days remaining in Eskom's winter outlook period (ending 31 August 2025), the system appears stable. According to Eskom's Winter Outlook published on 5 May 2025, loadshedding should not be necessary if unplanned outages remain below 13,000MW. The current figure of 10,846MW falls well below this threshold.

However, if outages were to increase to 15,000MW, loadshedding would still be limited to a maximum of 21 days out of the 153-day winter period and restricted to Stage 2 – a significantly better scenario than previous winters.

Call to Protect Infrastructure

Eskom has issued an appeal to customers to help protect transformers during winter by avoiding illegal connections. The utility warns that meter bypassing and unauthorized connections place immense strain on the network, often leading to transformer overloads, equipment damage, and in severe cases, explosions and extended outages.

To prevent damage to critical infrastructure, Eskom indicates it may implement load reduction in high-risk areas during peak hours. Customers are urged to purchase electricity only through accredited vendors and to regularize their electricity usage.

Outlook

The data suggests Eskom's system performance has stabilized considerably compared to previous years, with the utility appearing capable of meeting winter demand without resorting to loadshedding under current conditions. The reduced reliance on diesel generation and improved EAF indicate structural improvements in the generation fleet.

However, the system remains vulnerable to unexpected major unit breakdowns, particularly with unplanned outages for the week of 11-17 July averaging 13,051MW – slightly above Eskom's base case estimate of 13,000MW. While this represents an improvement from previous weeks, it remains 559MW higher than the same period last year.

The next six weeks will be crucial as South Africa continues through the winter period. Eskom plans to provide another update on 25 July 2025.

Key Terms Explained

Energy Availability Factor (EAF): A percentage measuring how much of Eskom's total generating capacity is available for use. Higher is better. A 62% EAF means that out of Eskom's approximately 47,000MW installed capacity, about 29,140MW is available to generate electricity.

Unplanned Capability Loss Factor (UCLF): The percentage of generating capacity lost due to unexpected breakdowns. Lower is better. A UCLF of 23.35% means that about 10,974MW of Eskom's generating capacity is offline due to unplanned outages.

Open-Cycle Gas Turbines (OCGTs): Emergency power generators that run on diesel fuel. They are expensive to operate but can be started quickly during system constraints. Eskom uses these as a last resort to prevent loadshedding during high demand periods.

Planned Maintenance: Scheduled downtime for power stations to undergo essential maintenance. Measured in megawatts (MW) of capacity temporarily removed from service. Some planned maintenance is necessary to ensure long-term reliability.

Load Factor: The percentage of time and capacity that a generation unit operates. For OCGTs, a high load factor indicates they're being used extensively, which is expensive and typically indicates system stress.

Load Reduction: A targeted power cut in specific high-risk areas (typically with high levels of illegal connections) to protect infrastructure from overloading, distinct from national loadshedding schedules.