This week's heatwave in five provinces, including Gauteng, has been named as one of the reasons South Africa was suddenly plunged into Stage 6 load shedding for the weekend.
The SA Weather Service announced the provinces of Gauteng, KZN, the Eastern Cape, Limpopo, and Mpumalanga would experience a heatwave between Sunday and Friday. This meant the average temperatures were 5°C warmer than the average maximum temperature of the hottest month for three or more consecutive days.
Electricity Minister Kgosientsho Ramokgopa said another big reason for the Stage 6 load shedding was the sudden spike in demand by over 1,500MW, the loss of five generating units and the need to replenish emergency generation reserves.
Eskom said unplanned outages were currently at over 15,901MW of generating capacity, while a further 5,800MW of generating capacity were currently out of service.
Bheki Nxumalo, the head of generation at Eskom, told a media briefing on Friday that the heatwave, with an increased demand for air conditioning and fans, could be blamed for the load shedding at Stage 6 level.
He said the solar load was about 1000 megawatts, while about 1,200 megawatts was contributing to the grid from wind energy.
“The increase in demand today can be attributed to the heatwave we are experiencing because we suspect it is coming from the air conditioning,” he said.
“The impact of the hot conditions on the partial (load losses) will see stations like Matimba when it is so hot; the current partial (load losses) are standing at about 7,000 megawatts. The main impact is at Matimba, and at some of the stations there are impacts on condensers, but the bigger impact is at Matimba,” he said.
Nxumalo said the generating unit losses at the Majuba, Lethabo, and Tutuka power stations were not an indication that they were failing to maintain their maintenance backlogs, but that it was an issue of boiler tube leaks occurring at the same time.
“If you look at the boiler tube leaks, it's not because of the maintenance backlog; even when you have the boiler, you can't work on every boiler tube.
“There are areas that are prone to high erosion, and at time to time the leaks happen, the problem comes when the leaks happen at the same time,” he said.
Ramokgopa apologised again for the load shedding and said they would provide a further update on the progress of the situation on Sunday.
He explained that another big factor in the load shedding was that they had to replenish emergency generation reserves.
“We want to give you the assurance that we are doing everything possible to deliver on our promise to eliminate load shedding,” he said.
“This is an unwelcome event we should frown upon ... We want to apologise sincerely because we understand the significant disruption to people and business is extreme,” he said.
Ramokgopa said they were looking forward to a number of units returning in December, which would provide a much-needed buffer.
Eskom has a long history of blaming weather for it's load shedding challenges.
– In December 2019, Eskom implemented Stage 4 load shedding for the second time that year and the power utility blamed wet coal stocks.
– In September 2021, showers with between 10mm and 20mm rain forced the power utility to take to Twitter that several areas, including some suburbs in Sandton, had suffered power outages due to the inclement weather.
– In May, Eskom warned of a heightened likelihood for Stage 8 load shedding during winter as the demand for electricity increases due to the cold weather.
And in July, following snowfall in parts of the country, Eskom complained that the weather conditions were leading to more load shedding as demand increased as people tried to keep warm using electrical appliances.
* This story has been updated to include the solar load and wind energy contributions to the grid.