Energy24.01.2025

Bad news for repairs at major Eskom power station

The critical repairs of three units at Eskom’s Kusile power station, which played a huge role in reducing load-shedding in 2024, have been delayed.

However, although things have not gone according to plan, Eskom has maintained that the restoration work would not cause load-shedding, as the utility’s generation recovery plan has continuously provided a broader capacity buffer.

The shutting down of Kusile Units 1, 2, and 3 in November 2022 contributed significantly to the country’s worst period of rotational power cuts.

These units boast a combined 2,160MW of generating capacity, roughly the same as the amount of demand Eskom sheds from the grid with two stages of load-shedding.

Eskom was forced to take the units offline after a part of the flue-gas desulphurisation (FGD) duct collapsed due to an internal build-up of concrete-like sludge caused by design defects and poor management.

The power utility devised a quick fix to bring the units back online and alleviate the risk of load-shedding.

While conducting long-term repairs on the FGD system, it proposed temporarily operating the units using chimney stacks.

These lack the emissions-reduction capabilities of the FGD system, which are necessary for Eskom to meet government-mandated pollution limits.

Cognisant of Eskom’s severe generation challenges, the Department of Forestry, Fisheries, and the Environment (DFFE) granted Eskom an exemption which would allow using the stacks until the end of March 2025.

A study by the Centre for Environmental Rights estimated that the workaround would result in 670 excess deaths, 3,000 asthma emergency room visits, and 1,400 pre-term births.

However, energy experts and economists agreed that the price of two stages of load-shedding would have been greater on the economy and could have indirectly caused more harm to South Africans’ wellbeing.

The units were brought back online a few weeks apart in late 2023 and have played an instrumental role in Eskom being able to fend off load-shedding for about 10 months.

Kusile Power Station with the three temporary stacks for Unit 1, 2 and 3 between the two larger FGD chimneys

Deadline coming in hot

The emissions exemption is set to expire in about two months. After 31 March 2025, Eskom will no longer be allowed to use the temporary stacks to run the units.

When MyBroadband previously asked the power utility for a timeline of the FGD repairs, it was optimistic it would have brought all the units back onto the system by the deadline.

Eskom said Kusile Unit 3 would be the first to be shut down and reintegrated with the FGD.

The power utility said this process would take 46 days, from 28 November 2024 to 12 January 2025.

However, in Eskom’s latest feedback, it said the unit was only taken offline in December 2024 and would only return to service in February 2025.

Unit 2 — the next in line for the switchover — was also not shut down as planned on 23 January 2025. Its outage was scheduled to last until 9 March 2025.

Unit 2 is now only scheduled to begin its switchover to the FGD sometime in February, after Unit 1 returns to service. Eskom did not say when it is planned to be back online again.

Unit 1 would have been shut down from 21 March to 13 June 2025. In its more recent feedback, Eskom said Unit 1’s switchover would last from late March to June.

The longer outage for this unit was part of Eskom’s general maintenance overhaul, which must happen six years into the unit’s operation.

Eskom assured that none of the units would continue operating with their temporary stacks past the exemption deadline.

The table below summarises Eskom’s original and revised timelines for bringing the

Original timelineRevised timeline
Unit 121 March to 3 June 2025Late March to June 2025
Unit 223 January 2025 to 9 March 2025February 2025 to unspecified date
Unit 328 November 2024 to 12 January 2025December 2024 to February 2025

Final unit’s synchronisation delayed

Another pertinent issue at Kusile is that the synchronisation of Unit 6 is at least three months behind schedule. It is the only unit at the power station that has never operated.

The unit was originally supposed to be synchronised to the grid by the end of November 2024 but this has been delayed to February 2025.

Eskom explained the delay was caused by material availability and setbacks in the boiler chemical cleaning process.

The power utility said that the first successful “fire on coal” of Kusile Unit 6 was carried out on December 20, 2024, and that the unit’s commissioning activities were now fully underway.

Following the expected synchronisation and further testing, it is planned to enter commercial operation in the third quarter of 2025.

Once Unit 6 is operational, the entire Kusile Power Station with 4,800MW of capacity will be online. According to Eskom, it will be the fourth-largest coal power station in the world.

The latest estimated completion date is 11 years after its original planned completion date and 17 years after its construction began.

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