By: ESI Africa

When system constraints do arise, they are managed through the targeted use of emergency reserves during morning and evening peak periods, said Eskom.

“The generation fleet continues to show ongoing solid momentum, with over half (57%) of Eskom’s fourteen coal-fired power stations now operating at an EAF above 70%, including three stations performing at a notable performance of more than 90%. An additional four stations are operating above 60%, reflecting the fleet’s growing stability and improved reliability.”

No loadshedding since May

The utility pointed out that since 15 May, there has been no loadshedding in the country, with loadshedding implemented for 26 hours – recorded between 1 April and 31 July 2025. 

“With 30 days of Eskom’s winter outlook period still remaining, the system remains well-positioned to maintain stability and meet demand effectively.

“As of today [Friday, 1 August], unplanned outages stand at 8,525MW, the lowest level in recent history, narrowly surpassing the 8,258MW recorded on 28 October 2024. The available generation capacity currently stands at 30,882MW.”

During the week of 25 to 31 July 2025, planned maintenance averaged 4,745MW. 

Over the same period, the EAF ranged between 64% and 71%, with the month-to-date average rising to 64.08%. 

This figure excludes the 720MW from Kusile Unit 6, which has been supplying electricity to the national grid since 23 March 2025, although not in commercial operation, Eskom reported.

To further strengthen grid stability, Eskom said it is planning to return a total of 3, 075MW of generation capacity to service ahead of the evening peak on Monday (4 August) and throughout this week.

Unplanned Capability Loss Factor

Between 1 April and 31 July 2025, the Unplanned Capability Loss Factor (UCLF), which reflects the percentage of generation capacity lost due to unplanned outages, further decreased to 28.58%. 

This represents a week-on-week improvement of approximately 0.4%, although it remains about 2.3% higher than the 26.28% recorded during the same period last year.

As of Thursday (31 July), the UCLF had dropped below the 20% mark, reaching 19.94%, signalling a significant and consistent improvement in generation performance.

The open-cycle gas turbine (OCGT) load factor further decreased last week, reaching 0.31%, down from the 1.86% recorded during the previous week (18 to 24 July 2025). This indicates less reliance on OCGTs, said Eskom.

From 1 April to 31 July 2025, diesel spend remains within the budget allocated for 1 April to 31 July 2025.

“The Winter Outlook, published on 5 May 2025, covering the period ending 31 August 2025, remains valid. 

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

Key performance highlights listed by Eskom

1. The average total unplanned outages over the past seven days stand at 10,206MW, compared to 10,229MW during the same period last year, a decrease from the previous week, 23MW lower year-on-year, and 2,794MW below the base case estimate of 13,000MW.
2. For the financial year-to-date, planned maintenance has averaged at 5,193MW, representing 11.05% of total generation capacity. This reflects a decrease from the previous week, but a 0.8% increase compared to the same period last year.
3. The year-to-date EAF stands at 59.88%, excluding the 720MW contribution from Kusile Unit 6. This figure is below the 62.84% recorded during the same period last year, mainly due to a 2.3% YTD increase in unplanned maintenance compared to the previous year.
4. Between 1 April and 31 July 2025, which falls within the winter period, Eskom spent R5.626 billion on fuel for its OCGT plants, generating 954.20GWh of electricity. This output is still higher than the 493.17GWh generated during the same timeframe last year.
5. The year-to-date load factor for open-cycle gas turbines (OCGTs) has marginally decreased to 9.55%, reflecting a 0.56% decrease compared to the previous week. This figure remains higher than the 4.93% recorded during the same period last year.

Call to protect Eskom infrastructure

Eskom also called for its customers to help protect transformers this winter.

“With loadshedding suspended and electricity demand rising during the winter period, Eskom urges all customers to act responsibly and help safeguard the power system. Illegal connections and meter bypassing not only constitute theft but also place immense strain on the network, often leading 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 power 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,” said the utility.

Eskom said it would next provide an update on the power system in South Africa on Friday, 8 August.