Eskom explains why load-shedding is back

A perfect storm of problems – including COVID-19, a series of unplanned breakdowns, and the coldest winter in a decade – led to the return of rolling blackouts in South Africa.

This is according to Eskom spokesperson Sikonathi Mantshansha, who told MyBroadband that despite increasing their available capacity over lockdown, factors including the cold weather and unplanned breakdowns resulted in the return of scheduled nationwide power outages.

Before load-shedding was re-implemented, Eskom stated there was an 80% probability of three days of load-shedding.

“This was based on an assumption of 11,000MW of unplanned losses, and taking into account the maintenance work conducted during the past two months,” Mantshansha said.

South Africa recently saw stage 2 load-shedding return, however, with the country now entering its sixth consecutive day of power cuts.

Mantshansha said Eskom was investigating the underlying cause of the outages which caused this unexpected period of load-shedding.

“Over the last two weeks, the losses have been consistently higher than 11,000MW, leading to load-shedding exceeding the three days projected,” he said.

“Eskom is now conducting an investigation into the underlying cause of these losses, particularly on equipment that did go through maintenance.”

COVID-19, reliability, and the coldest winter in a decade

Mantshansha said that during the lockdown, the power utility used the reduction in demand to execute a significant amount of short-term maintenance on its system.

This helped it to recover close to 3,000MW of generation capacity that was not available prior to the lockdown.

“On the other hand, the challenges presented by working through the COVID-19 pandemic and the lockdown have meant that some of the reliability maintenance (longer) outages had to be deferred or outage scopes reduced,” he said.

This longer maintenance will have to be accommodated later in the year to improve the reliability of major power plants.

Despite these issues, Eskom has succeeded in adding capacity to its grid over the lockdown.

This was not enough, however, to cope with the freezing-cold temperatures experienced across the country during the winter season.

“It should be noted that Eskom went into the lockdown with available capacity of just over 30,000MW,” Mantshansha said. “Available capacity has increased to about 34,000MW now.”

“This enabled Eskom to increase supply to the highest so far this year, at 33,460MW.”

“But it being the coldest winter in a decade, demand has also risen significantly, rendering the additional available capacity insufficient to meet demand,” he said.

No guarantees for 2020

Looking ahead, it is unclear for how long load-shedding will continue, or whether it will return sporadically throughout the rest of the year.

Eskom will at some point need to reduce its available capacity as it conducts much-needed long-term maintenance, and this carries an increased risk of load-shedding.

However, allowing ageing infrastructure to run constantly without conducting this crucial maintenance also reduces the reliability of the national power grid, again increasing the risk of load-shedding.

“The unreliability and unpredictability of the generating fleet means that the risk of load-shedding will remain until the design faults of the new build units at Medupi and Kusile have been resolved and critical and necessary maintenance is performed on the balance of the fleet,” Mantshansha said.

“As we have consistently stated in January 2020, March, and in July, a lot of work is still required to get us through this.”

Now read: Powerships are ready to stop load-shedding in South Africa

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Eskom explains why load-shedding is back