Eskom power system remains stable as winter demand peak approaches

South Africa’s power system continues to operate reliably as the country navigates the winter electricity demand period, with Eskom maintaining grid stability without load shedding for more than two months.

The utility announced on Friday, 25 July 2025, that 3,960MW of generation capacity will return to service ahead of Monday evening’s peak demand period to further strengthen grid stability.

This comes as the power system shows sustained reductions in unplanned outages while effectively managing winter electricity requirements.

No Eskom load shedding since mid-May

Eskom has not implemented load shedding since 15 May 2025, recording only 26 hours of power cuts between 1 April and 24 July 2025.

The achievement marks a significant improvement in system reliability during the critical winter period.

“With 37 days of Eskom’s Winter Outlook period still remaining, the system remains well-positioned to maintain stability and meet demand effectively,” the utility stated.

As of Friday, unplanned outages stood at 11,695MW while available generation capacity reached 30,236MW.

Friday’s electricity demand was expected to reach 27,715MW, with current capacity sufficient to meet both daily requirements and anticipated weekend demand.

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Eskom system performance shows improvement

During the week of 18 to 24 July 2025, planned maintenance averaged 5,050MW.

The Energy Availability Factor (EAF) ranged between 62% and 66% over the same period, with the month-to-date average increasing to 63.11%.

“To further strengthen grid stability, Eskom is planning to return a total of 3,960MW of generation capacity to service ahead of the evening peak on Monday, 28 July 2025, and throughout the coming week,” the utility confirmed.

The Unplanned Capability Loss Factor (UCLF), which measures generation capacity lost due to unplanned outages, decreased to 28.99% between 1 April and 24 July 2025.

This represents a reduction of approximately 0.5% compared to the previous week, though it remains about 2.4% higher than the 26.60% recorded during the same period last year.

As of 24 July, the UCLF stood at 23.79%, indicating notable performance improvements.

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Reduced reliance on emergency generation

According to Eskom, the open-cycle gas turbine (OCGT) load factor decreased significantly this week to 1.86%, down from 8.6% recorded during the previous week of 11 to 17 July 2025.

This reduction indicates a decrease in reliance on expensive emergency generation.

“From 1 April to 24 July 2025, diesel spend remains within the budget allocated for 1 April to 31 July 2025,” Eskom said.

Eskom winter outlook remains valid

The utility’s Winter Outlook, covering the period ending 31 August 2025, remains unchanged.

The outlook suggests that load shedding will not be necessary if unplanned outages remain below 13 000 MW.

“It indicates that load shedding will not be necessary if unplanned outages stay below 13,000MW. If outages rise to 15,000MW, load shedding would be limited to a maximum of 21 days out of 153 days and restricted to Stage 2,” the utility explained.

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Diesel spend correction

Eskom issued a correction regarding diesel expenditure figures published in the previous week’s Power Alert.

“We identified a discrepancy in the reported diesel amount. The actual diesel spend should have been R5.554 billion, not R5.897 billion as stated,” the utility corrected.

The utility explained that the figure 5,897 was actually the R/MWh rate and was mistakenly captured as total spend instead of the per-unit cost.

“This regretfully resulted in an inadvertent overstatement of the diesel spend, which we hereby correct.”

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Year-to-date performance metrics

For the week of 18 to 24 July 2025, unplanned outages averaged 11 555MW.

This represents a decrease from the previous week but remains 1 077MW higher than the same period last year and 1,445MW below the base case estimate of 13 000MW.

According to Eskom, for the financial year-to-date, planned maintenance has averaged 5 221MW, representing 11.11% of total generation capacity.

This reflects a decrease from the previous week but shows a 0.7% increase compared to the same period last year.

“The year-to-date EAF stands at 59.42%, excluding the 720MW contribution from Kusile Unit 6, which has been supplying electricity to the national grid since 23 March 2025, although not yet in commercial operation,” Eskom
reported.

This figure remains below the 62.42% recorded during the same period last year, mainly due to a 2.4% increase in unplanned maintenance compared to the previous year.

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Fuel costs and generation output

Between 1 April and 24 July 2025, Eskom spent R5.616 billion on fuel for its OCT plants, generating 952.41GWh of electricity.

This output significantly exceeds the 493.16GWh generated during the same timeframe last year.

The year-to-date load factor for OCTs has marginally decreased to 10.11%, reflecting a 0.53% decrease compared to the previous week.

However, this figure remains substantially higher than the 5.23% recorded during the same period last year.

Customer advisory on infrastructure protection

With load shedding suspended and electricity demand rising during winter, Eskom has urged customers to act responsibly to help safeguard the power system.

The utility highlighted concerns about illegal connections and meter bypassing, which constitute theft and strain the network infrastructure.

These activities often lead to transformer overloads, equipment damage, and in severe cases, explosions and extended outages.

“To protect critical infrastructure, Eskom is compelled to implement load reduction by switching off lower during peak hours in high-risk, isolated areas to prevent potential damage.

“To help maintain a stable and uninterrupted electricity supply, customers are strongly urged to avoid bypassing meters and refrain from illegal connections. Electricity should be purchased only through Eskom-accredited vendors, and users are encouraged to regularise their electricity usage,” the utility advised.

“These steps are essential to ensuring safe, reliable, and fair access to electricity for all. Eligible households are encouraged to register for free basic electricity with their local municipalities,” Eskom added.

The utility will provide its next update on Friday, 1 August 2025, or communicate significant changes as they occur.

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