South Africa could be subjected to as high as stage 11 load-shedding this winter, despite Eskom saying stage 6 is unlikely over the winter months.

This is according to Virtual Energy and Power director Clyde Mallinson, who analysed historical winter load-shedding data and the condition of Eskom’s coal power plants to make rotational power cut predictions.

Mallinson said Eskom must lift the coal fleet’s capacity factor (CF) to at least 50% to prevent high levels of load-shedding over the winter months.

Capacity factor is a ratio of actual power output relative to the theoretical maximum that could have been output over a period.

“Load-shedding maximum and average monthly results based on coal fleet capacity factors as predicted for January and February,” the caption accompanying his predictions said.

“Need to lift the coal fleet CF to 50%, to stave off a winter of discontent.”

In February 2022, he explained that Eskom’s coal generation fleet was in such a bad state that less than 40% was operational.

Mallinson used historical data to predict the maximum and average levels of load-shedding for the rest of the year.

Worst-case scenario load-shedding predictions based on coal fleet capacity factors.

He created two scenarios — average and maximum (or worst-case scenario) — based on two assumptions.

The first is that 2023’s load profile will be similar to 2022, and the second is that load-shedding is strongly correlated to demand, as well as the capacity of coal plants.

If Eskom’s coal fleet CF remains at its current level of around 40%, Eskom would have to implement an average of stage 4 power cuts to stabilise the grid between April and September 2023.

In the worst-case scenario at this capacity factor, South Africa would be subjected to stage 8 load-shedding in April, stage 9 in May, and stage 11 in June.

After that, it will vary between stages 8, 9, and 10 before dropping to stage 7 in October 2023.

If the coal fleet’s CF increases to around 50%, Mallinson predicts that Eskom will implement a maximum of stage 6 load-shedding in June.

It would need stage 2 power cuts in June, July, and September at this capacity factor under the “average” scenario to keep the grid stable.

While several people, including former Eskom CEO André de Ruyter, former Eskom executive Robbie van Heerden, and Intellidex capital markets head Peter Attard Montalto, have warned of intensified load-shedding over winter, the country’s newly appointed electricity minister disagrees.