How Eskom dodged load shedding this week

Power utility Eskom was forced to increase its use of open-cycle gas turbines (OCGTs) to 2022-levels amid a prolonged outage of Koeberg Unit 1.

Eskom confirmed that it shut down Koeberg’s Unit 1 generator on Wednesday, 11 September 2024, with the power utility taking it offline at the same time Unit 2 is offline.

Each unit of the power station produces 980MW of power, and with both offline, South Africa is short close to 2,000MW, or the equivalent of two stages of load shedding.

To compensate for the outage, the power utility had to ramp up the burning of diesel in the OCGTs.

According to the Bureau for Economic Research (BER), the utility’s data shows OCGT use over the past week was around the same level as 2022—though it remained below the levels seen during the worst of load shedding at the end of 2023.

Eskom last noted that its OCGT load factor between 1 September to 12 September 2024 was 8.62%—lower than 27.9% reported in 2023. This period does not cover the time Koeberg Unit 1 was down.

However, the BER said that Eskom’s other operational improvements—on top of the OCGT usage—was enough to keep load shedding at bay.

“With more OCGT usage, other unplanned outages being lower than last year, and residual demand being lower, Eskom has managed to avoid load-shedding,” the BER said.

Energy expert Chris Yelland criticised Eskom this week for taking Koeberg offline without letting the public know. The incident was exposed via the media, and Eskom acknowledged it five days later.

Yelland shared feedback from Eskom, explaining that Unit 1 was “conservatively and safely shut down” on 11 September after one of its block valves failed its three-monthly routine test.

“The unit was shut down in order to restore redundancy of the steam pressure relief system in line with the operating technical specifications,” the power utility said.

“The intervention has been completed, and the unit is in the process of being safely returned to service. All stakeholders who were required to notify were informed as per the stringent protocols.”

Eskom said the shutdown has not impacted its load-shedding suspension, adding that its summer outlook remains in force.

While South Africa has been without load shedding for close to 180 days, Eskom’s summer outlook still makes provision for national outages. However, if load shedding were to ever return, it would be capped at stage 2, it said.

The group expects no load shedding as long as breakdowns remain below 13,000MW. If breakdowns exceed 15,000MW, load shedding could return – but capped at stage 2.

A scenario of no load shedding should be achievable, given that Eskom has managed to keep outages below the 13,000MW throughout winter.

Eskom’s last update noted that unplanned outages have been averaging between 9,800MW and 13,100MW, well below the Summer Outlook projections.

Regardless, the return of Koeberg unit 1 cannot come soon enough, with South Africa being hit by a cold snap this weekend.

A severe low-pressure system is set to sweep over large parts of the country, bringing rain, cold weather, and snowfall. These conditions are also expected to produce a spike in electricity demand.

Eskom told EWN that its systems are ready to deal with the inclement weather, and it should have enough capacity to keep load shedding at bay.

Read: Eskom load shedding outlook for summer – what needs to happen to keep outages away