Eskom’s System Operator does not have set load-shedding levels beyond stage 8, general manager Isabel Fick told journalists on Sunday morning.
Should South Africa need to shed more than 8,000 megawatts of electricity load, the Eskom System Operator would issue individual instructions to provinces and municipalities.
“We as a System Operator would instruct a number of megawatts to be taken off per province,” Fick said.
“The instruction would be carried out by the various control centres of the municipality and the distribution on a provincial basis.”
The System Operator ensures the stability of South Africa’s national electricity grid by balancing how much electricity is generated to match the amount of electricity being consumed.
Fick spoke during an emergency press briefing after Eskom announced a sudden escalation to stage 6 load-shedding in the early hours of Sunday morning.
Eskom said generating units went offline at its Kusile and Kriel power stations, necessitating the move from stage 5 to stage 6.
Although the status of Eskom’s generating system is dire, it is not clear that South Africa is at risk of load-shedding beyond stage 8.
Eskom COO Jan Oberholzer said they expected to return 18 generating units to service in the coming week with a combined capacity of 9,000MW.
However, ten units representing 6,000MW of capacity are currently running with known risks.
Four of these with a combined capacity of 2,000MW are considered high-risk.
One stage of load-shedding is equal to roughly 1,000MW of power.
Oberholzer explained that Eskom has roughly 6,000MW of emergency generating capacity. This comprises diesel-powered open cycle gas turbines and pumped water storage hydroelectric power stations.
These are not currently being heavily used to let Eskom recover diesel and water reserves and avoid higher stages of load-shedding during South Africa’s evening and morning peaks.
Eskom plans to bring 5,000MW of capacity back online by Monday evening, of which 1,590MW should be returned on Sunday.
No risk of total blackout
Eskom has assured there is no risk of a total grid collapse, as load-shedding was designed precisely to prevent a blackout.
Regardless, Fick stated in response to media questions that Eskom was adequately prepared for a catastrophe and regularly conducted “black start” tests.
“A black start test is basically when you test various pieces of [power] plants to look at their adequacy, should we have an unfortunate situation when we black out the whole system,” Fick explained.
“[Black start tests] happen on a three-yearly basis for different parts of the plant. There’s also a number of different tests performed at different intervals,” she said.
For this reason, it’s difficult to give a simple answer for when Eskom did the last full black start test.
However, Fick said the power utility conducted one of its main black start tests on 23 August 2022.