First look at stage 16 load-shedding — up to 25,600MW power cuts

The National Energy Regulator of South Africa (Nersa) has published a consultation document detailing a planned revised load-shedding approach that allows for up to stage 16 power cuts.

The document, NRS 048-9 Electricity Supply – Quality of Supply: Code of Practice – Load reduction practices, system restoration practices, and critical load and essential load requirements under system emergencies, is now open for public comment.

Once all consultation processes have been finished and relevant inputs considered, it will be reworked as the NRS 048-9 Code of Practice Edition 3 and replace the current Edition 2 standing code that Eskom’s System Operator uses to define load-shedding stages.

Aside from allowing higher stages of power cuts, the draft document proposes load-shedding stages enabling the System Operator to give instruction to reduce demand based on a percentage of the country’s national non-curtailment load at a given time.

Under the current regime, one stage of load-shedding is supposed to equal up to a 1,000MW demand reduction, regardless of the total load at the time of its implementation.

Stage 2 allows for up to a 2,000MW demand reduction; stage 3 permits up to 3,000MW, and so on.

If the revision proposed in the consultation document is approved, the System Operator can demand that power distributors drop their demand by between 5% and 80%, depending on the declared load-shedding stage.

At stage 1, the reduction required through load-shedding will be 5% of non-curtailed demand.

For each stage of load-shedding that follows, distributors will be required to reduce their load by a further 5%.

Each load-shedding stage will also determine the percentage of load Eskom’s load curtailment customers will have to cut.

Unlike general users, this will be based on curtailment customers’ normal demand profile.

The table below outlines the proposed reductions in load under each load-shedding stage for general and load curtailment customers.

Proposed demand reductions under NRS 048-9 Electricity Supply Edition 3
Stage Reduction through load-shedding Reduction through load curtailment
1 5% of demand 10% reduction in normal demand profile
2 10% of demand 10% reduction in normal demand profile
3 15% of demand 15% reduction in normal demand profile
4 20% of demand 20% reduction in normal demand profile
5 25% of demand 30% reduction in normal demand profile
6 30% of demand 30% reduction in normal demand profile
7 35% of demand 40% reduction in normal demand profile
8 40% of demand 40% reduction in normal demand profile
9 45% of demand 50% reduction in normal demand profile
10 50% of demand 50% reduction in normal demand profile
11 55% of demand Reduction to essential loads or as instructed by System Operator
12 60% of demand Reduction to essential loads or as instructed by System Operator
13 65% of demand Reduction to essential loads or as instructed by System Operator
14 70% of demand Reduction to essential loads or as instructed by System Operator
15 75% of demand Reduction to essential loads or as instructed by System Operator
16 80% of demand Reduction to essential loads or as instructed by System Operator

It remains to be seen precisely how this change will impact load-shedding schedules.

It appears as though each stage under the new approach will require cutting more load than the current stages.

South Africa’s winter peak demand typically ranges between 30,000MW and 32,000MW. 5% of that demand would work out to a demand reduction of 1,500–1,600MW.

Even in the period of lowest electricity demand — during the December holidays — the effective reduction will be higher.

During this time, Eskom typically sees demand hovering between 23,000MW and 24,000MW, 5% of which would work out to 1,150–1,200MW.

This adjustment would also mean that comparing Eskom’s historical load-shedding stages to future load-shedding will become extremely challenging, if not impossible.

For example, while stage 2 load-shedding previously only allowed for cutting up to 2,000MW of load, it will now mean between 2,300-3,200MW is shed, equal to the amount of power cut between stage 3 to stage 4 load-shedding.

In a worst-case scenario, stage 16 load-shedding will see a reduction of between 18,400MW and 25,600MW of non-curtailed load.

The table below hypothesises the load reduction under each proposed load-shedding stage.

Theoretical MW reductions under proposed load-shedding stages
Stage Low demand scenario:
23,000-24,000MW
High demand scenario:
30,000-32,000MW load
1 1,150–1,200MW 1,500–1,600MW
2 2,300–2,400MW 3,000–3,200MW
3 3,450–3,600MW 4,500–4,800MW
4 4,600–4,800MW 6,000–6,400MW
5 5,750–6,000MW 7,500–8,000MW
6 6,900MW–7,200MW 9,000–9,600MW
7 8,050–8,400MW 10,500–11,200MW
8 9,200–9,600MW 12,000–12,800MW
9 10,350–10,800MW 13,500–14,400MW
10 11,500–12,000MW 15,000–16,000MW
11 12,650–13,200MW 16,500–17,600MW
12 13,800–14,400MW 18,000–19,200MW
13 14,950–15,600MW 10,725–20,800MW
14 16,100–16,800MW 21,000–22,400MW
15 17,250–18,000MW 22,500–24,000MW
16 18,400–19,200MW 24,000–25,600MW

It remains to be seen how the reductions above will translate into load-shedding schedules.

Nersa has given the public and relevant stakeholders until 22 September 2023 to make submissions on the document.

Comments will then be collated and considered for the final proposed code.

The draft document is available on Nersa’s website and can also be downloaded here.


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First look at stage 16 load-shedding — up to 25,600MW power cuts