Air conditioners caused stage 6 load-shedding — Eskom
According to a senior executive at Eskom, the increased use of air conditioners and fans by affluent South Africans is partially to blame for the recent stint of stage 6 load-shedding.
Lethabo Power Station general manager Karabo Rakgolela told the Sunday Times that the recent heatwave resulted in a huge spike in power usage.
“We had a stable grid for most of September and October, and two weeks ago, suddenly, the problems started when we started seeing the partial load losses begin to climb,” said Rakgolela.
“I can place a lot of the reasons for our current problems at the door of the extreme swings in temperature we had.”
“The Sunday just before Black Friday, we had some units down, and we had started recovering them when we were hit by the incredible heatwave, and suddenly usage spiked by about 1,500MW,” said Rakgolela.
“In a heatwave such as this recent one, you can see the usage go up as the entire affluent South Africa switches on their airconditioning and fans, and that usage stays up as long as it stays warm.”
He added that high temperatures also cause problems at power stations — such as tube leaks and tripping units.
“The heatwave put us in a bad position. We had failures on some units, and I know we use the term ‘unexpected’ very loosely, but these failures we did not anticipate,” said Rakgolela.
“We ended up running on diesel deep into the night.”
Lethabo Power Station
Over-committing emergency reserves
As stage 6 load-shedding returned, Electricity minister Kgosientsho Ramokgopa stated that Eskom had over-used its emergency reserves, contributing to increased power cuts.
“On the back of that cluster of units that had gone out, what it meant is that we had to significantly engage our emergency reserves,” he said during a media briefing on Friday, 24 November.
“For purposes of protecting the grid, we need to ensure that we continue to protect the reserves, so we are not going to engage them at a heightened intensity, and as a result, we don’t have the benefit of the 4,600MW that we would automatically draw from our emergency reserves.”
Independent energy analyst Pieter Jordaan told BusinessTech that Eskom’s OCGT usage had far exceeded the 6% mark allowed for by the National Energy Regulator of South Africa (Nersa).
“Eskom’s OCGT utilisation rate for Week 46 was 40%, and on Sunday, it was 63%,” he said.
“Most of Sunday’s OCGT generation was used to replenish pumped storage, adding a 33% premium to the near R7 per kWh cost.”
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