Eskom load shedding

Prepare for even worse load shedding from August. This graph shows why.

Eskom load shedding 2021

  • Eskom is prepared for 20% of the power grid’s capacity to be cut due unexpected breakdowns.
  • This coincides with a further 12% reduction due to urgent maintenance.
  • Eskom could in theory burn through diesel to keep the lights on during winter, but tight budgets and deadlines suggest winter is going to get bad.
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Eskom has warned of serious energy constraints towards the end of 2021, and its forecasts suggest things will be bad from August onwards.

The company is tying to keep up with urgent maintenance while burning expensive diesel to keep the lights on. But its long-standing financial constraints are being worsened by municipal debts (totalling R35.2 billion) and operating losses (exceeding R20 billion) – while the pandemic saw delays in its maintenance plans, plus disruptions in the supply of coal and diesel. 

“Eskom has to reiterate that there will continue to be an electricity supply shortfall of approximately 4,000MW over the next five years,” said CEO André de Ruyter at a "status of the system" briefing on Monday – even as electricity rationing continued.

One graph from the briefing captures how dependent Eskom will remain on expensive emergency generation – just barely meeting projected demand if all goes well.

Eskom load shedding 2021

UCLF – Unplanned Capability Loss Factor PCLF – Planned Capability Loss Factor OCGT – Open Cycle Gas Turbine


“Capacity challenges will remain one of the key challenges South Africa will continue to grapple with. Most of our power stations are in need of maintenance to improve reliability and some have also long passed their midlife," said De Ruyter.

South Africa’s load shedding conundrum is compounded by the urgent need for planned maintenance, which takes approximately 12% of Eskom’s capacity offline, and unexpected breakdowns, which can account for a fifth of total nominal capacity.

While South Africans have had to endure 19 days of load shedding since the start of 2021, Eskom has warned of greater energy constraints between August and November.

“The drive to implement the reliability maintenance and refurbishment projects in order to address the unreliability is under way to get the plant performance back to acceptable levels by late 2021,” said Eskom’s chief operating officer, Jan Oberholzer.

“The public is therefore cautioned to expect an increased risk of load shedding during this period.”

In mid winter Eskom will hold back on maintenance and use open cycle gas turbines to mitigate the need for rationing. But once the coldest weather passes, in August, it plans to redouble maintenance efforts (and so the planned capability loss factor or PCLF), while throttling back on diesel use.

If at any point unexpected breakdowns pass the 10,000MW mark – current levels exceed 11,700MW – while planned maintenance is being carried out, South Africa will be subjected to load shedding.

The finest narrowest margins for error are towards the end of September through the end of October, when peak usage is likely to exceed capacity.

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