Stage-6 blackouts will be implemented with immediate effect and will continue until at least Monday.
State-owned electricity monopoly Eskom said this is due to insufficient emergency reserves and generating capacity.
The utility says it is continuing to closely monitor the power system and will publish a further communication later on Friday.
There have been warnings all week that the grid is stretched and only being kept under control through lower demand and less maintenance; and stage-4 load shedding was implemented on Wednesday.
Energy expert Chris Yelland told TechCentral on Friday that there are cyclical factors to load shedding in summer, as the energy availability factor can decline for many reasons.
The most obvious one is that the “dry-air-cooled power stations” have to reduce their output in summer, as the air outside is hotter – and this week in particular, when South Africa is experiencing a heatwave.
Some of the biggest power stations in South Africa – Matimba, Majuba, Medupi and Kusile – are dry-air-cooled and this could explain some of the partial load losses.
Also, planned maintenance is routinely undertaken in summer, but South Africa now has no spare units to take up the slack of units switched off for maintenance, leading to inadequate generation reserves.
“We are so close to the edge now that there are no units to close the gap,” said Yelland. “And then there are all the random breakdowns and unplanned problems for all reasons. Even if the maintenance is planned, once work begins, because maintenance in the past has been so poor, they find that spares are not available or the people needed to undertake the work are not there.
“This is another reason for a delayed return to service — and could explain our sudden return to stage 6,” he said.
Electricity minister Kgosientsho Ramokgopa will hold a media briefing at 3pm on Friday to outline plans to deal with the latest crisis, which comes months before South Africans are expected to vote in a general election that polls suggest the ANC will lose without the support of coalition partners. — © 2023 NewsCentral Media