How South Africa’s new 16 stages of load shedding will work

A new load shedding structure is on the cards for South Africa, which will extend the maximum load shedding possible from stage 8 to stage 16.

Last week, the National energy regualtor Nersa published a consulation document that will change how load shedding in South Africa is condcuted for public comment.

Speaking with Newzroom Afrika, Chair of the management committee of the National Rationalised Specifications (NRS) Association of South Africa, Vally Padayachee, said that the new load shedding system should prevent the grid from collapsing after stage 8 load shedding.

As per the current guidelines, system operators across the country would have to implement emergency procedures if stage 8 occurs to prevent a grid collapse. Although Padayachee said that these operators are highly-skilled, he says that the current system allows for human error, increasing the chances

He said that the proposed load shedding schedule will do away with human error, with a system in place to accommodate for as high as stage 16.

That said, he repeatedly noted that South Africa is unlikely to ever reach stage 16 – where 80% of the grid would have to be turned off. He said that including stage 16 is for unintended consequences of load shedding, which the NRS is considering as a prudent organisation.

The NRS has, however, shifted the goal posts for the “unlikely event” of load shedding worsening in the past. In 2010, the NRS introduced a system with only four stages of load shedding and then upgraded this to 8 stages of load shedding in 2019.

Although Padayachee said that South Africa is unlikely to hit stage 16, he said that there is a very real possibility that South Africa hits stage 9, 10 and 11 due to the strain in generation capacity.

Why the change

One of the most obvious changes seen in the new consultation document is the new way of measuring the intensity of load shedding.

Presently, load shedding is measured in 1,000MWs that is removed from the grid. For instance, 4,000 MW equates to four stages of load shedding.

The newly proposed structure will instead be expressed as a percentage of demand, with 5% of demand correlating to one stage of load shedding. Thus, 20% of demand accounts for four stages of load shedding.

Padayachee said that the change in system is necessary as Eskom never actually uses the 1,000 MW system, as it varies significantly.

“I can tell you, conclusively, that they never use that measure (1,000 MW = 1 stage) in their load shedding because it varies. And it could have varied from 800MW to 1,2000 MW. That is why it caused a confusion between stage 6 and stage 8,” he said.

The new percentage system is calculated by forecasting peak demand, then adding in the reserve margin of roughly 2,500 MW, then subtracting the curtailment load of 7,000MW from the key customers, and then dividing that number to get a percentage – which declares the stage of laod shedding.

Padayachee noted South African’s could experiance less load shedding as the margin in lessened via the new system.

Below is how the load shedding strcuture will change:

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