Alarm bells for load shedding this winter

Economists, energy experts, and Eskom warn that the power system remains strained due to high demand, unplanned outages, and increased planned maintenance—which are not good signs as the country heads into winter.

These concerns were highlighted in the Minerals Council South Africa’s electricity update for March 2025, which is an analysis of the power system by economist, André Lourens.

The report noted that South Africa’s power system remained constrained in March 2025, with the Energy Availability Factor (EAF) largely unchanged at 57.5%, compared to 57.4% in February.

Lourens added that the narrow margin between dispatchable generation and electricity demand underscored these challenges.

The average demand for the month stood at 22,509 MW, while dispatchable generation averaged 22,357 MW, necessitating 55 hours of load shedding during March.

From 7 to 10 March, a sudden loss of 2,700 MW in generation capacity—including Koeberg Unit 2 (930 MW) and two Kusile units—led to increased reliance on Open-Cycle Gas Turbines (OCGTs) to meet demand.

“As these reserves were depleted, load shedding became necessary to restore emergency reserves,” said Lourens.

Later in the month, additional load shedding was also implemented following the failure of five generating units, two of which were from the Cahora Bassa hydroelectric system in Mozambique. Breakdowns were frequent and without warning in March.

Another concern is the fact that March saw the highest average utilisation of the OCGTs since the worst of load shedding in 2023.

Additionally, when tracking the historical Energy Availability Factor (EAF) over recent years, 2025 is trending downward after a promising start to the year.

“In 2025, the EAF appears to be aligning with the lower levels seen in the first few months of 2024 and remains well below the pre-COVID highs of 2019,” said Lourens.

Data released by Stats SA on 3 April also indicated that seasonally adjusted real electricity generation fell by 2.5% year-on-year by the end of February 2025.

In its latest update, Eskom agreed that the power system is strained, with a meagre reduction in the Unplanned Capacity Loss Factor (UCLF) or unplanned outages.

“Load shedding remains suspended; however, the power system is constrained due to ongoing increased planned maintenance and high electricity demand driven by overcast weather conditions nationwide,” it said.

The utility added that the UCLF for the financial year-to-date (1 to 3 April 2025), stands at 28.67%, only improving slightly from 31.92% in the same period last year.

Commenting on the increased planned maintenance, Eskom said this is being done to enhance fleet reliability for peak winter demand while also ensuring compliance with environmental and regulatory requirements.

Despite this, Eskom said that the system is strained but stable, with sufficient emergency reserves in place to manage peak demand.

Commenting on the latest update, energy analyst Chris Yelland said that with year-to-date EAF of 56.73% and unplanned outages hovering around 30% of the Eskom fleet, this is not where South Africa would want to be.

Additionally, following the return of stage 6 load shedding at the end of February, Yelland previously stressed that this highlighted the erratic and unreliable nature of South Africa’s coal-fired power generation. 

“At around 80%, there is far too much coal-fired power in our mix, which poses a significant risk to the economy,” Yelland said. 

He warned that unless Eskom addresses its fundamental issues, further power disruptions in South Africa are likely.

Energy analyst Professor Hartmut Winkler echoed these concerns, stating that although the return of load shedding was surprising, South Africans should expect intermittent power cuts to continue. 

“We were very lucky over the last year that we went so long without load shedding,” Winkler said. 

He explained that Eskom had been “walking close to the line,” meaning that any unexpected disruption could easily trigger power cuts. 

His forecast suggests that intermittent load shedding could persist for another two to three years as Eskom struggles to stabilise its generation fleet.

In its latest update, Eskom said that it would announce its winter outlook soon, which will give South Africans a better picture of what to expect.

The winter outlook should be published closer to the end of April.