Jan Oberholzer, chief operating officer of Eskom Holdings. (Photo: Waldo Swiegers / Bloomberg via Getty Images) | Power lines in Johannesburg, South Africa, 10 November 2021. (Photo: EPA-EFE / Kim Ludbrook) | Mural of a child holding a bulb in Orlando West, Soweto. (Photo: Felix Dlangamandla) | Eskom acting generation MD Rhulani Mathebula. (Photo: Supplied) 
“Due to the vulnerability and unpredictability of the power system, coupled with the major capital projects, maintenance and major repairs to be executed starting during the next few months, the risk of continued load shedding remains quite high,” Eskom’s group chief operating officer, Jan Oberholzer, said on Tuesday.
In a statement, the power utility said these plans would remove 2,300MW of generation capacity from the ailing power grid, and further increase the implementation of rolling blackouts.
“Eskom cautions the public to anticipate the increased risk of load shedding until these problems are resolved over the next six to 12 months.”
In an Eskom state-of-the-system briefing on Tuesday afternoon, Oberholzer said a unit at Koeberg power station would undergo maintenance and refuelling from 8 December until June next year.
“Unit 1 of the Koeberg Nuclear Power Station, which has enjoyed 384 days of uninterrupted supply until today, will be shut down for normal maintenance and refuelling, and the replacement of the three steam generators as part of the long-term operation to extend the operating life of Africa’s only nuclear power station.”
This will remove 920MW of generation capacity from the national grid.
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Poor generation
Oberholzer said the power utility had generally good performance in the network side of its business, encompassing transmission and distribution. However, there is still unsatisfactory performance on the generation side — particularly its coal fleet.
Eskom’s year-to-date energy availability factor (EAF), which is the proportion of its plant available to dispatch energy, is at 58.53% — below its target of 65% for the financial year. High levels of planned maintenance, combined with a high rate of breakdowns, had contributed to the low EAF, said Oberholzer.
He said that this year there had been 468 unplanned automatic grid separation trips — which is when a unit’s safety mechanisms cut it off from the grid to prevent instability. The target had been 392 trips.
“We really need to get [a handle] on this unreliability and unpredictability of some of the units at some power stations,” he said. Another “area that needs attention” is Eskom’s partial load losses, which are at 5,930MW — above the tolerance level, which the power utility set at 3,695MW.
Another problem: “Vandalism and theft are beginning to play a significant part in the challenges that Eskom has on the electrical network.”
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‘We do not have money to burn diesel’
Open cycle gas turbines (OCGTs), which are used during failures in the power fleet to limit the stages of power cuts, require diesel to run. Because of the system constraints, Eskom has been forced to use more than the anticipated levels of diesel to run its OCGTs.
“In order to supply the demand of the country, we have to run our open cycle gas turbines extensively,” said Oberholzer.
As at 31 October, the power utility had spent in excess of R12-billion — more than it had budgeted for — on diesel to run its OCGTs. Oberholzer warned that if Eskom were to stop running its OCGTs because of its financial challenges, the stages of load shedding would increase.
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Eskom’s initial budget for this financial year using diesel was R6.1-billion, said Oberholzer. “We then had the revised provision of R11.1-billion. Now, the R11.1-billion has been exceeded as well.
“We do not have money to burn diesel any more. We will be forced to implement load shedding because we do not have the money to burn the diesel at the rate that we have been doing until now.”
Oberholzer said municipal debt to Eskom remained a challenge. At the end of July, Daily Maverick reported that municipal debt to the power utility stood at R49.7-billion. As at 31 October, Eskom has “outstanding debt exceeding R52-billion”, Oberholzer said.
Head of generation resigns
Oberholzer also announced the resignation of Eskom’s acting head of generation, Rhulani Mathebula, who leaves at the end of November. Mathebula’s resignation comes six months after his appointment to the position, following the resignation of his predecessor, Phillip Dukashe, in May this year, due to stress.
Oberholzer said that in tendering his resignation, Mathebula had stated that the demands of the role had become “unbearable”, citing the negative impact it had on his health and family time.
The manager of Lethabo Power Station, Thomas Conradie, will act as generation executive while the replacement process is under way. DM