Eskom has spent almost R5 billion on diesel in 2025

Eskom’s diesel-powered backup units are seeing higher usage in 2025 compared to last year, with the utility having spent R4.76 billion on fuel in the year to date.

This comes as the utility continues to struggle to increase its energy availability factor (EAF).

At the start of Winter, Eskom assured South Africans that the increased reliability of its network would reduce the chances of load-shedding this season despite increased demand during the colder months.

Eskom CEO Dan Marokane said load-shedding will not be necessary if unplanned outages remain below 13,000 MW.

If outages reach 15,000 MW, load-shedding would be limited to a maximum of 21 days out of 153 days and restricted to stage 2.

However, in June, Eskom’s unplanned outages reached levels nearing that threshold, sparking fears of load-shedding.

On Friday, 27 June 2025, breakdowns at Eskom’s power plants reached 15,137 MW, above the threshold for potential stage 2 load-shedding.

Despite Eskom crossing this threshold and the recent cold weather boosting demand, the utility said in a press statement that the power system remains stable.

Eskom said its unplanned losses (UCLF) rose, partly due to delays in returning units from planned maintenance, including 800 MW from Medupi Unit 4 since 1 June 2025.

However, the utility said it has sufficient available capacity of 30,703 MW to meet the evening peak demand of 28,810 MW. 

It added that scheduled maintenance has been scaled down to boost supply, and the EAF is currently 60.61%. 

The utility further explained that it has sufficient emergency reserves in place, which are strategically deployed to support demand during morning and evening peak periods

This emergency reserve refers to Eskom’s open-cycle gas turbines (OCGTs), the diesel-powered units the utility uses when supply from its other units cannot meet demand.

Researchers from the Bureau for Economic Research (BER), Roy Havemann and Julia Iles, said Eskom’s OCGTs have seen higher usage than last year. 

They explained that although the OCGT weekly load factor dropped to 7.25%, compared to 9.12% the week before, year-to-date usage (11.37%) and fuel spending remain elevated. 

Year-to-date, Eskom has spent approximately R4.76 billion on fuel for the OCGT fleet, generating 810.24 GWh. 

This is higher than the 442.65 GWh generated during the same period last year.

However, Eskom has said the use of its OCGTs and, accordingly, fuel spending are expected to decline as more units are returned to service from long-term repairs.

The graph below, courtesy of the BER, shows how much higher Eskom’s unplanned outages are in 2025 compared to 2024.

One step forward, two steps back

In 2024, Eskom experienced its strongest performance in years, with a stable power supply and minimum load-shedding. This came after the utility had its weakest performance on record in 2023.

This strong performance continued into 2025, with short, sporadic bouts of load-shedding in the first few months of the year.

However, despite this progress, Eskom’s EAF, which shows the percentage of time the power station was available for use when it was needed, 

Eskom has previously stated that if the EAF could be improved to around 70%, load-shedding would be a thing of the past, and South Africa would have electricity security.

In October 2022, Eskom’s board and former Public Enterprises Minister Pravin Gordhan unveiled its EAF targets for the next three years.

They set an EAF target of 60% by March 2023, 65% by March 2024, and 70% by March 2025.

While Eskom has made immense progress over the past two years, it missed all of these targets.

In a recent social media post, energy analyst Chris Yelland explained that Eskom’s unplanned outages are higher in 2025 compared to 2024. 

“So, even with planned maintenance now dropping below 2023 and 2024 levels for the same period, the EAF remains stubbornly low at around 60%, two percentage points below that for the same time in 2024,” he said.

Trends in Eskom’s EAF can be seen in the graph below, courtesy of Yelland and EE Business Intelligence.