Eskom told the regulator on Tuesday that its immediate focus was on returning 14 coal units to service over the coming four days, in an effort to recover 8 012 MW of coal generation so as to ease load-shedding, which was being implemented at Stage 5.

Although the National Energy Regulator of South Africa’s (Nersa’s) hearings are concerned primarily with the State-owned utility’s request for a 32% tariff hike, regulatory members had requested an update on load-shedding and its implications for the utility’s costs during the first day of hearings on Monday.

Members were particularly concerned about Eskom’s newly-published energy availability factor (EAF) assumption of 59% for the coming two financial years, which would result in a heavy reliance on the open-cycle gas turbines (OCGTs).

Eskom is currently assuming that the load factor of the OCGT plants will rise from 5% to 12%, which would trigger a surge in its diesel costs to R16.9-billion in 2023/24 and R17.7-billion in 2024/25.

For the year to date, a period that coincides with South Africa’s worst-ever load-shedding, Eskom has already spent R7.7-billion on diesel and has been operating the OCGT plants at an average load factor of 14%.

On the second day of hearings, Eskom generation executive Eric Shunmagum revealed that the utility was aiming to return eight units, with a combine capacity of 3 990 MW, during the course of Tuesday, September 20.

It was targeting three more, representing 1 115 MW, on Wednesday and another three units, with a combined capacity of 1 837 MW, on Friday, so as to ramp down rotational cuts to Stage 2 by the weekend.

Shunmagum said the generation unit’s operational recovery plan was geared towards improving the EAF from 59% to at least 70% from the end of March 2024 onwards, by when some older stations would have been decommissioned and Kusile completed.

Until then, the OCGTs would be used extensively, as had been the case since the start of the current financial year on April 1, when the load factor had dipped below 10% in just a single month (August) and had been as high as 18.8% during June.

Questioned about the prudency of using the OCGT plants so extensively, Eskom argued that the cost to the country was “much cheaper when compared to higher levels of load-shedding”.

Beyond the immediate return to service plan for the current week, Shunmagum said the recovery plan would focus on the ‘Top 6 priority stations’ of Tutuka, Duvha, Majuba, Kusile Matla and Kendal.

“All our efforts will be going into those stations as we begin shutting the oldest stations in the next two to three years.”

After March 31, the focus would shift to the next set of priority stations of Matimba, Lethabo, Medupi, Kriel and Arnot.

“These stations were specifically selected as they are amongst the highest contributors to the unplanned load losses and any improvement at these stations will see a massive change in the EAF,” Shunmagum asserted.

Priority would also be given to a successful execution of the steam generator replacement projects at Koeberg Unit 1, following serious difficulties at Unit 2.

Koeberg Unit 2 was returned to service in August without the steam generators having been replaced because of a lack of project preparation by Eskom and had since tripped, further intensifying September load-shedding.