The truth behind lower stages of load shedding in South Africa

While electricity minister Kgosientsho Ramokgopa has been quick to attribute lower stages of load shedding to a better performance by Eskom, the latest data shows that things at the embattled power utility haven’t changed much at all.

This means that the lower stages of load shedding seen in June were largely thanks to other factors – like lower demand from consumers and more input from renewables.

Independent energy analyst Pieter Jordaan compiled the data made available through Eskom’s Data Portal to find the real reason behind Eskom’s surprisingly good performance in June.

“Why did we have less load shedding in June? The two main reasons given by the utility are that there was lower power demand than expected and that they had more generating capacity available than in May; that was helped by better renewable generation,” he said.

This is mostly supported by the data, which shows that the utility did improve its performance. But little else changed.

While Eskom’s performance – measured by its energy availability factor (EAF) – did improve compared to previous months (59% vs 50-55% in the preceding months), the number of breakdowns were generally the same as when load shedding escalated in September 2022 (~33%).

One of the more notable changes came from a massive reduction in planned maintenance, which halved from the work done in April (14% to 7%), keeping more megawatts on the grid. This is typical for the winter months.

In general, however, the picture of Eskom’s overall performance is not all that different from earlier in the year when high stages of load shedding were permanently in effect – and the group is still underperforming compared to previous years where load shedding was not always happening.

The key difference, then, is on the demand side, Jordaan noted.

The reality

Up until last week, winter demand had been much lower than anticipated. Eskom had planned for a base case of 34,000MW, anticipating up to 37,000MW – hence the warnings before winter of the risk of moving to stage 8 load shedding.

However, demand dropped as low as 27,000MW and typically hovered under 30,000MW and hit peaks of 32,000MW.

“Following a week of accurate forecasting, a cold snap increased demand from a Monday evening peak of 32,000MW on 3 July to 34,000MW on 10 July. The low load-shedding levels in the prior week meant that the razor-thin capacity reserves were already breached on 4 and 5 July’s peaks.

“The normal winter demand levels (starting 9 July) and an insufficient load shedding buffer had the effect of unexpected power deficits. These deficits would have needed cover by means of high levels of load curtailment or the emergency 2.2 GW reserve margin – the latter being an extreme measure,” Jordaan said.

Jordaan noted that the first winter weather for 2023 boosted the wind generators and lowered the residual demand that Eskom needed to provide from non-renewables. The better performance in the weeks that followed (to end June) was due to the same effect.

“The June demand was, on average, significantly lower than last year. The return to normal demand
levels over the last week meant the return of stage 6 load shedding,” he said.

The reality of the situation is that Eskom continues to operate on these thin margins, and energy experts have warned that higher stages of load shedding are again likely if this delicate balancing act isn’t successful.

If another cold snap hits the country – as is forecast for this week – demand will likely shoot up again, forcing Eskom to use up its reserves, burn more diesel, and eventually escalate load shedding to counter these effects.

Demand on Tuesday’s peak (18 July) was already back up to 32,000MW, with Eskom needing to shed over 4,600MW from the grid.

If, however, demand can be contained, then lower levels of load shedding can continue.

Exiting winter, though, will see the regular maintenance schedules return, with more units being taken offline. If Eskom has not boosted its generation or added more capacity to the grid by then, load shedding will continue.

Read: Load shedding: South Africa walking a ‘razor thin’ line