The temporary stacks being introduced at the Kusile coal power station, where three previously operational units have been out of service for ten months, have been built and interim CEO Calib Cassim has expressed optimism that the units could be returned to service earlier than previously indicated.

All three units, which have a combined capacity of 2 100 MW, became inoperable after the Unit 1 flue duct collapsed on October 23 due to a build-up of slurry. The collapse also compromised the unit 2 and 3 flue ducts, which share a common chimney with the Unit 1 flue.

In the face of intense loadshedding, Eskom secured environmental authorisation earlier this year to build three temporary flues that bypass Kusile’s flue gas desulphurisation plant until March 31, 2025. A decision that is being challenged in the courts.

The solution was proposed by Eskom in an effort to reintroduce the units earlier than would have been the case under a scenario where permanent repairs were implemented.

The temporary repair is expected to cost between R200-million and R250-million and will enable the three units to produce 720 MW apiece electricity while the permanent repairs are undertaken.

The cost of the permanent repair has not yet been finalised.

It was communicated previously that the first unit was likely to return towards the end of November, followed by the second unit in mid-December and the third on Christmas eve.

However, Cassim told editors on Thursday that the Kusile temporary stacks had been built and that it was, thus, possible that two of the units could begin producing by mid-November.

He indicated Unit 3 would be reintroduced first and was likely to be followed in quick succession by Unit 1, with the reintroduction of Unit 2 to take longer, owing to the configuration of the temporary solution.

In addition, Unit 5 could be synchronised to the grid in late November, which would add additional production from the power station, which currently only had Unit 4 operating. Although Unit 5 would operate only intermittently as tests were carried out ahead of full commercial operation.

Updates were also provided on the other major long-term outages and refurbishments that, together with Kusile, collectively involved 8 652 MW, including:

• A repair to Medupi Unit 4, which Eskom expects to bring into operation in July 2024, using a second-hand stator;
• The return of Koeberg Unit 1 on November 3, following a major outage slip during an extended outage to prepare the unit for a further 20 years of operation. Unit 1 is due to be returned ahead of a Unit 2 outage, which will start on November 7;
• The replacement of Kriel cooling tower 4 by March 2024;
• The completion of Majuba Unit 3’s re-bagging by March 2024; and
• The cooling tower replacement at Tutuka by October 2024.

Chairperson Mpho Makwana said the initiatives formed part of the ‘Generation Operational Recovery Plan’ approved by the board earlier in the year following stakeholder consultations and which aimed to recover Eskom’s energy availability factor (EAF) to 70% by March 31, 2025.

“While there is a gradual improvement in some areas of generation, our recovery efforts have not fully yielded the desired outcomes, owing to the extensive work that needs to be done against a vulnerable and unreliable power system,” Makwana said, while describing the EAF goal as a stretch target.

Eskom failed to meet the 60% EAF target set for the end of March 2023, reporting an EAF of 56%.