South Africa gets rules for up to stage 16 load-shedding

The National Energy Regulator of South Africa (Nersa) has approved guidelines for implementing load-shedding up to Stage 16.

The regulator published the latest revision of the load-shedding Code of Practice, consolidating load-shedding stages into a single system from Stage 1 to Stage 16.

It was developed by experts from Eskom, the Energy Intensive User Group, metros, and the regulator itself, among others.

This is the third edition of the code. The second, published in 2017, had guidelines for load-shedding up to Stage 8.

The National Rationalized Specifications (NRS) Association submitted the new edition to Nersa for approval in May 2023.

The code aims to help Eskom and municipal distributors mitigate the impact of high load-shedding stages while preventing a grid collapse.

It also allows Eskom’s system operator and electricity distributors to take emergency action if necessary.

The Eskom System Operator is responsible for ensuring the stability of South Africa’s electricity grid and sets the level of load-shedding needed to do so.

Changes to the code include:

• The consolidation of the load-shedding stages into a single system from Stage 1 to 16;
• Clarification on methods for setting baselines for curtailment customers;
• Increased control of how load-shedding and load-curtailment are determined and carried out to improve grid stability and provide more certainty to curtailment customers;
• Giving curtailment customers the right to reduce consumption by 10 % per every two load-shedding stages, up to stage 10, 50 % of their load, or to go to essential loads, rather than being forced to essential loads after Stage 4;
• The specification of compliance and reporting requirements (general and real-time); and
• Guidance on implementing smart metering technology to reduce the impact of load-shedding on customers.

In May 2023, Eskom proposed new load-shedding guidelines up to Stage 16 to ensure that load-shedding beyond Stage 8 is carried out effectively if necessary.

“The NRS048-9 Revision 2 describes load-shedding stages up to Stage 8 and obligates all network operators (distributors and municipalities) to develop, publish and implement these schedules when instructed to do so by the System Operator,” it said.

“Beyond Stage 8, the System Operator will instruct each province to reduce by a fixed [megawatt] amount.”

“NRS048-9 Revision 3 proposes load-shedding schedules up to Stage 16 in order to make load-shedding systematic and orderly,” Eskom added.

The power utility’s proposal came after NRS chair Vally Padayachee revealed that the organisation had updated the load-shedding Code of Practice to go beyond Stage 8.

Amid concerns that load-shedding higher than Stage 8 might have been required in winter last year, Padayachee said an update to the code was necessary to protect the grid’s integrity.

He explained there would be a high probability of human error if Stage 9 load-shedding or higher was required without guidelines in place.

“Then the System Operator and municipal electricity distributors would have to use their own respective operating procedures to protect the national grid,” said Padayachee.

“In that environment, the propensity for human error is very possible.”

Failure to follow the code, or the absence of the necessary guidelines, could result in the grid frequency fluctuating above or below 50Hz — the frequency that keeps the grid alive.

If this were to happen, the grid could collapse, plunging the country into darkness. Restarting the grid is difficult and time-consuming, and South Africa could be without power for weeks if that happened.