Shaun Jacobs26 March 2023

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Energy expert Clyde Mallinson and acting head of generation at Eskom Thomas Conradie have tempered the optimism surrounding the decrease in load-shedding severity over the last week.

Eskom’s Conradie added that nothing concrete has changed and that there is still a “tough year ahead” and a “tough winter in terms of load-shedding”.

Last week, the power utility announced that six coal-fired power stations had an Energy Availability Factor of 70% (EAF), a milestone last achieved in May 2022.

Conradie said the EAF improvement was expected as many generation units return to service from planned maintenance.

However, Eskom’s coal-powered fleet also showed improved performance.

Clyde Mallinson, an energy analyst at Virtual Energy and Power, said that according to the data, there “has been an improvement in the coal fleet capacity factor”, which is an indicator of how much power Eskom’s coal fleet generates.

In particular, Camden, Duvha, and Matla have been on a sustained upward trend due to a reduction in plant breakdowns, while Lethabo, Matimba, and Medupi continued their good performance.

This resulted in South Africa’s first full day without load-shedding in 2023, a sign that Eskom’s performance is improving.

Long-term outlook is still bleak

When one looks into the reasons for the reduction in the severity of load-shedding and Eskom’s forecast for winter, it is apparent that the relief will be short-lived.

Mallinson attributes the decrease in load-shedding severity to predominantly short-term factors, including lower demand and less planned maintenance.

Eskom performs the bulk of its maintenance in the summer months with reduced demand, allowing more units to be taken offline.

As the country moves into winter, this maintenance plan eases off to allow the utility to “throw everything it has” at the higher winter demand.

However, this easing off appears to have begun earlier than usual this year, Mallinson said.

Eskom’s performance target is to reach an Energy Availability Factor (EAF) of 60% by the end of March 2023. Currently, Eskom’s fleet is at 56% EAF.

Mallinson said Eskom has, therefore, eased up on maintenance earlier than usual in an attempt to reach the 60% target.

This is unsustainable in the long term as maintenance must be done.

Conradie echoes Mallinson’s concerns in saying that Eskom’s system remains “very much at risk”, with roughly 6,000MW of generation being unreliable.

He said the performance of Eskom’s fleet in 2023 “will be a bit up and down” as there is “inherent unreliability in our fleet”.

However, Conradie does expect to see an improvement in EAF in the coming months, as Eskom’s maintenance plan will bear fruit.

Eskom’s EAF is expected to decline in April, with 5,100MW of generation capacity taken offline for maintenance.

A longer-term factor contributing to reduced load-shedding is the repair of the transmission line from the Cahora Bassa hydropower plant in Mozambique.

It allows the plant to increase its contribution to South Africa, which, at full capacity, equals almost a full stage of load-shedding.