Despite an expected increase in electricity demand, it is possible that load-shedding will be less frequent by the time winter arrives.

South Africa got its first taste of Eskom’s regular power cuts this year within the first week of January, after a unit at Koeberg nuclear power station was taken offline earlier than expected.

This was followed by another bout of power cuts in the next week, when two generation units at the Kusile power station tripped due to the failure of the main coal feed conveyor belts, while a unit at the Kriel and Duvha stations also tripped due to unforeseen breakdowns.

These types of outages are expected to be experienced for some years still, as Eskom deals with its ageing power plants and a lack of proper maintenance conducted at these facilities in recent years.

The utility’s most recent system status report showed that it expects a likely scenario that includes breakdowns in excess of 16,400MW over the next three months.

This is when taking into account both unplanned outages and planned losses in capacity due to maintenance.

Eskom must load shed whenever this figure climbs above 11,000MW, which would mean that up to Stage 4 load-shedding is probable on a weekly basis until April.

While many South Africans may be concerned about the intensity of load-shedding during a period when demand is lower, Eskom has explained that this is not a sign of worse load-shedding to come when the need for electricity increases.

Ramping up during summer

According to the power utility, its reliability maintenance program is ramped up during the summer period.

“Our maintenance is planned in such a manner to ensure higher availability during the winter,” Eskom has told MyBroadband.

This process requires that many units are taken out of service simultaneously, which results in a loss of capacity.

When Eskom does planning for maintenance, it assumes different levels of unplanned allowance, with the base case being no load-shedding.

However, under its current assumptions, it anticipates the total loss of capacity to be between 12,000-14,000MW for summer.

“In the planning scenarios considered, at an unplanned unavailability of up to 14,000 MW of capacity, up to Stage 3 load shedding is possible,” Eskom explained.

“Until the reliability maintenance program can be completed there is likely to be periods of load-shedding, particularly during the summer months when maintenance is ramped up as the demand reduces.”

“In short, the risk of load-shedding during this period remains elevated.”

For winter, the assumption of loss in capacity drops down to 11,000-13,000MW, which means that less severe load-shedding is expected.

Eskom added, however, that there may still be instances where the unplanned allowance and depletion of emergency reserves could result in higher stages.

The impact of IPPs

The utility also elaborated on the impact that independent renewable energy power producers have had on its generation capacity to date.

“In April 2018, Eskom entered into 27 power purchase agreements (PPAs) with renewable energy independent power producers – totalling 2 305MW,” the utility stated.

13 of these projects have achieved commercial operation and offer a total installed capacity of 1,048MW, Eskom said.

However, Eskom stated that renewable energy only has a send-out capability around a third of its installed capacity – which would equate to around 340MW with the current providers.

The remainder of the projects are scheduled to enter commercial operation during the course of 2021. An anticipated 12 projects will bring the total installed capacity of 1 082MW, with one project scheduled in 2022 with an installed capacity of 75MW,” Eskom said.

In addition, the final project scheduled to enter commercial operation will be 100MW in November 2023.