Stage 6 load-shedding, which has happened once, looks set to become a far more common occurrence as Eskom’s plant breakdowns remain at dangerously high levels.

Stage 6 means 6,000MW are dropped from the grid to avoid the system becoming unstable. In Gauteng, where load-shedding intervals last four hours, Eskom customers could be without electricity for an average of 10 hours a day.

At the weekend, Eskom implemented stage 2 load-shedding, dropping 2,000MW from the grid. But had demand been at normal levels, with everyone back at work, it would have been necessary to move to stage 6 on Saturday and Sunday.

Demand over the holiday period is about 4,000MW lower than normal.

Chris Yelland is MD at EE Business Intelligence, which tracks demand and Eskom plant performance, said that in the last week of January 2018 electricity demand was at 28,864MW. In the last week of December demand had dropped as low as 25,294MW.

Eskom said plant breakdowns must be limited to 9,500MW of capacity if it is to avoid load-shedding. Over the past two weeks breakdowns have been substantially higher, reaching 14,096MW on Friday. Monday’s breakdowns stood at 13,119MW at 6am.

Despite efforts by Eskom management to turn operations around over the past two years, the energy availability factor — the percentage of its plant that is available to dispatch energy — has continued its downward trend. In 2019, Eskom’s energy availability factor was 67%, said Yelland. This compared with 72% in 2018 and 79% in 2017.

The last two weeks of December saw the energy availability factor hit 59.7% and 58% respectively.