Eskom says it will implement stage 2 load shedding from 2pm on Wednesday until 5pm on Saturday.
The power utility said stage 2 load shedding was necessary due to the loss of a unit each at the Medupi, Duvha and Kendal power stations in the morning.
Earlier, Eskom’s chief executive officer (CEO) André de Ruyter and his management team briefed the media on the state of the power grid.
This follows Eskom’s warning late on Tuesday that five generation units had failed throughout the day at its various power stations.
The power utility said a generating unit each at Kusile and Majuba power stations was taken offline to repair boiler tube leaks, while a generating unit each at Kriel, Majuba and Matimba had tripped.
“The return to service of a generating unit each at Kendal and Tutuka were delayed,” Eskom said in a statement.
De Ruyter said early on Wednesday morning they were able to return back to service unit 2 at Kriel Power Station.
However, at 5.45am, unit 3 at Medupi Power Station tripped, adding to Eskom’s generation capacity woes.
“That’s another big unit of 720MW of capacity [and] we expect this unit to be back by evening peak [on Wednesday],” De Ruyter said.
He added that they had also lost unit 5 at Duvha Power Station due to breakdowns.
“Unfortunately, we also lost Duvha unit 5 and that is at a capacity of 520MW. At this point in time, we do not have a forecast of a return to service time, but our crews are working flat out in that unit.”
De Ruyter said during the day on Wednesday they expected that Unit 4 at Kendal power station will return to service, adding 640MW into the power grid.
To minimise the risk of load shedding in the meantime, he said Eskom was currently using diesel for its open-cycle gas turbines (OCGTs) which was not ideal.
“At the moment we’ve got eight OCGTs in operation. This is of course not desirable as OCGTs are intended to operate on a peaking basis only… so the continued high levels of diesel consumption are not desirable,” De Ruyter said.
De Ruyter said Eskom would do maintenance and repairs over the weekend at seven units at several of their power stations. This means Eskom will take off 3,842MW from the system, he said.
“Demand over the weekend typically is significantly lower so we don’t expect this maintenance programme to cause load shedding, but of course if we have breakdowns the risk will remain,” he said.