Eskom guzzles diesel

Eskom says its usage of diesel-powered open-cycle gas turbine (OCGT) power stations surged at the start of January to avoid load-shedding.
In the week between Friday, 3 January and 10 January 2025, breakdowns were only slightly lower than last year, resulting in higher-than-expected reliance on emergency generation capacity.
“Over the past seven days, the average total unplanned outages stood at 14,155MW, reflecting a slight improvement compared to the 14,611MW recorded during the same period last year,” the power utility stated.
“This performance is primarily due to delays in returning some units undergoing planned maintenance to service combined with the loss of generating units as a result of boiler tube leaks.”
Eskom said that as of Friday, 10 January, unplanned outages were at 14,077MW, which was 1,077MW higher than the summer 2024 base case.
“To meet demand under these circumstances, reliance was placed on a higher open-cycle gas turbine load factor for the period under review, which has since decreased,” it assured.
“An additional 4 150MW of generation capacity is expected to return to service by Monday evening.”
Eskom said it continued to use the summer break and the lower demand from industry to increase planned maintenance activities.
This was to further improve the reliability of its generation fleet for the winter period, which starts on 1 April 2025. Eskom said its maintenance averaged roughly 8,000MW.
Currently, the capacity offline for ongoing planned maintenance stood at 5,787MW, which Eskom said was aligned with its summer maintenance strategy.
Eskom explained that its strategic use of peaking stations, including pumped storage and OCGTs, remains key in managing electricity demand during peak times, particularly during evening peaks from 17:00 to 22:00.
The state-owned power utility reported that it spent approximately R9.39 billion on OCGTs between 1 April 2024 and 9 January 2025, generating 1,527.02GWh.
“This is significantly lower than the R25.67 billion spent during the same period last year, which produced 4,094.48GWh.”
Eskom said the OCGT load factor for 1 April 2024 to 9 January 2025 stabilised at 6.56%, compared
to last year’s figure of 17.60%.
However, the OCGT load factor for 1 to 9 January 2025 was 20.05% — higher than the 7.97% for
the same period last year.
“But this is seen as temporary given the current improvement,” Eskom stated. “Diesel usage remains below the year-to-date budget.”

Eskom announced that it had reached 289 consecutive days without implementing load-shedding since 26 March last year.
Although its diesel usage during the past week was high, Eskom said it has realised financial year-to-date diesel savings of R16.28 billion.
“This is about 63.4% less than the R25.67 billion spent during the same period last year, due to the ongoing structural improvements in generation performance,” it said.
“The year-to-date (1 April 2024 to 9 January 2025) energy availability factor is at 61.99%, a significant improvement of around 7.0% compared to the same period last year (55.05%).”
Energy availability factor (EAF) is a measure of how much capacity Eskom can deliver relative to how much capacity it has installed at its power stations.
Eskom said its weekly EAF declined slightly from 57% at the beginning of the financial year to 56.97% from 6 January 2025 to 9 January 2025.
However, compared to the same period last year, Eskom’s EAF improved slightly from an average of 54.65% to 56.97% over the past week.
“Koeberg, Medupi and all peaking stations achieved an average EAF of 70% and above. Two other power stations recorded EAFs above 60%,” the power utility said.