Real reasons for lower load-shedding

Energy analyst Chris Yelland said there are good reasons South Africa has been experiencing lower levels of load-shedding, despite earlier warnings of a dark winter.

Acting Eskom CEO Calib Cassim recently warned that the country faces a “difficult winter” as it heads into the cold months, with 3,000MW less capacity than last year.

Energy expert Clyde Mallinson said Eskom faces an 11,000MW electricity shortfall during winter, which would result in 2,000MW load-curtailment and stage 9 load-shedding.

Electricity Minister Kgosientsho Ramokgopa has warned of a dark winter ahead, saying Eskom faces a shortfall of 8,000MW to 10,000MW in winter. This equates to stage 10 load-shedding.

However, Yelland said that while Eskom still faces a shortfall, the country will have a more reliable experience in these next three months compared to the past three months.

This is because the electricity supply in winter is far more than some may think, and demand is far lower for some projects.

He said there are four main reasons why South Africa could avoid a dark winter.

1. Maintenance is performed in summer.
2. Lower maintenance in winter and air-cooling power stations.
3. Renewable energy.
4. Decreased industrial demand.

Each of these reasons is explained in more detail below.

Reason one

According to Yelland, despite what many may believe, winter months have traditionally not been linked to higher load-shedding stages.

“If you look at the energy availability factor over a year, you notice that it starts with fairly low availability in summer months,” he said.

“It progressively increases towards winter, hitting a peak in the middle of winter and then slowly dropping off again.”

This indicates that there is more available generation capacity in the winter than in the summer months. 

This is because Eskom performs maintenance in summer to be ready for the winter demand. Therefore, there are fewer breakdowns in winter.

Reason two

According to Yelland, Eskom performs less maintenance in winter. Typically, Eskom will perform 6,000MW of maintenance in summer, which drops to 2,000MW in winter.

“That releases an extra 4,000MW to meet demand. So, on the supply side, the supply is better in winter than in summer,” he said.

Yelland added that some power stations, especially the air-cooled, large, newer power stations, can generate more electricity in cold weather than in hot weather, as the cold assists with the air cooling.

Therefore, these power stations can have fewer partial load losses in winter. “But in plain language, they perform better in winter than in summer.”

Reason three

According to Yelland, solar photovoltaics on domestic and commercial installations have been progressively increasing every year, which is starting to make a difference.

“If you bring on 1,000MW of rooftop solar PV, and that’s what’s happening over a period, that reduces one load-shedding stage,” he said.

In some areas of the country, the wind also picks up in winter months, and wind power performs better in these months.

“So we’re seeing, in this winter, a significantly increased supply.”

Reason four

One of the reasons often cited for higher load-shedding stages during winter months is increased demand, as people try to stay warm using electricity.

While demand does increase somewhat in winter, Yelland said it is not as much as people often think. Domestic demand increases in winter, but industrial demand tends to decrease.

This is because energy-intensive industries that use smelters, for example, would need more electricity during winter to continue operating, which makes their energy costs more than triple. 

In addition, the smelters tend to shut down during winter, which requires more maintenance.

Since many businesses cannot afford these added costs, they stop operations during winter, bringing demand down.