Counting Eskom chickens

Energy expert Anton Eberhard has cautioned against counting Eskom’s chickens before they’ve hatched.

This comes after electricity minister Kgosientsho Ramokgopa talked up Eskom’s improving energy availability factor (EAF).

EAF (called “capacity factor” elsewhere in the world) measures how much power generating capacity Eskom had available at a specific moment in time.

In a press briefing on Sunday, Ramokgopa once again highlighted that Eskom’s power plant performance has been improving.

Ramokgopa said it’s no accident South Africa has seen a reduction in load-shedding.

He said Eskom had increased its generation to over 29,900 megawatts, with demand at around 30,000 megawatts.

Although this is good news, Eberhard explained that the numbers don’t yet show a reversal of fortunes at the ailing state-owned power utility.

“I, along with all South Africans, want the performance of Eskom to improve and power cuts to end,” Eberhard said.

“But let’s be careful in our analysis. The availability of generator units always improves in winter with less maintenance and lower partial load losses.”

Last year was a notable exception to this historical trend, thanks to an unprotected strike of Eskom workers that plunged South Africa into stage 6 load-shedding.

It took Eskom the latter half of 2022 and the start of 2023 to dig itself out of the hole the strike pushed it into.

Eberhard referred to fellow energy analyst Chris Yelland’s most recent chart of Eskom’s weekly EAF to illustrate his point.

Yelland explained that the EAF for the 2023 calendar year-to-date is 53.66%, where it was 59.44% for the same period last year.

“This year [remains] worse than before, despite the usual winter improvements in EAFs,” Eberhard stated.

“We have not yet seen a sustained trend over six months or more of improved performance.”

Stated differently, this year’s line (in solid grey) must cross back above last year’s trend line (in dashed orange) before there is reason to truly celebrate.

“We can expect another decline in the second half of the year, and the EAF target of 65% will probably not be met. Not being negative, just realistic,” Eberhard said.

Although Eskom probably won’t reach its 65% EAF goal, Eberhard said we could see an uptick in availability if three generating units at Kusile return to service as promised.

“Before we bring out the champagne to celebrate the imminent end of power cuts in South Africa, we need to track the trend over months in Eskom plant breakdowns and whether we’re adding new power generation fast enough,” said Eberhard.

He said that South Africa is experiencing reduced load-shedding for several reasons.

“First, residual demand that Eskom needs to meet is lower than expected — and significantly lower than last year,” Eberhard explained.

“Industrial demand is down with higher winter tariffs and energy-intensive kit off for maintenance.”

Residual electricity demand is also lower because self-dispatched wind energy is much higher, sometimes shaving up to 2GW — equivalent to two full stages of load-shedding.

“Distributed solar is also beginning to make an impact,” Eberhard said.

“Power cuts have also reduced because Eskom has more generation available, in part because of lower partial load losses in colder winter temperatures, less plant off for maintenance and apparently some marginal improvements at some power stations.”

Another factor is that Eskom has been running its open-cycle gas turbine peaking power stations hard.

Eberhard said over R30 billion of unbudgeted funds is being spent on diesel.

“How will this be funded?” he asked.


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Counting Eskom chickens