Power utility Eskom says that a total collapse of the national grid would be an unforeseen event, and its system operator would not be able to provide advanced warning should it occur.
In the event that the grid collapses, this would result in a total blackout – which would leave the entire country without any power for “a few weeks” as it recovers.
The group published a guide on the load shedding process this week, informing the public about how it manages energy supply and how load shedding fits into the overall picture.
South Africa was plunged into stage 6 load shedding over the weekend, with warnings from industry experts that things could get a lot worse as the week progresses.
While load shedding was reduced to stage 5 on Tuesday, the grid remains incredibly volatile and vulnerable to further breakdowns.
In a media briefing on Sunday (18 September), Eskom noted that its load shedding schedules go up to stage 8, where 8,000MW is pulled from the grid. If capacity issues go beyond this level, it is up to the System Operator to make specific determinations, per province, for how much additional power needs to be pulled.
Eskom said that load shedding is its last resort to prevent a nationwide blackout.
When the system is under strain, it first turns to voluntary or contracted emergency demand reduction where large energy consumers – mostly industrial – are asked to reduce their load on the grid.
If this fails to balance the demand, load shedding is implemented.
“If preventative measures, including load shedding, are insufficient – the national grid will collapse. A blackout is unforeseen, and therefore, the System Operator will not be able to make an announcement in advance,” it said.
“A national blackout will have massive implications, and every effort is made to prevent this from occurring. Depending on the nature of the emergency, it could take a few weeks for the grid to recover from a blackout.”
Eskom CEO Andre de Ruyter said that there was no immediate threat of a blackout occurring, and the fact that Eskom was able to manage the demand and supply through load shedding – even at stage 6 – was a sign that the system is working, as load-shedding was designed precisely to prevent a total blackout.
Despite this, the utility said it is adequately prepared for a catastrophe and regularly conducts “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,” it said.
“[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.”
The power utility conducted one of its main black start tests on 23 August 2022.