Load shedding: Hiccup in Eskom’s power plans

Eskom has shared bad news, announcing that the planned maintenance on Koeberg Unit 1 will be delayed by about a month, with the unit now expected to only return to operation by August.

The utility shared an update on the planned maintenance of Unit 1 at the Koeberg Nuclear Power Station in Cape Town on Tuesday.

Offline

The 930 MW Unit 1 is currently offline for the second phase of a long-term operation extension.

It was initially planned to be back online in July after undergoing scheduled maintenance, including fuel refuelling and statutory tests, as part of the life extension process.

Load shedding

Eskom said the revised return date for Koeberg Unit 1 will not increase the risk of load shedding.

“The Winter Outlook released on 5 May 2025, which covers the period until 31 August 2025, remains valid. Importantly, the planned return of 2 500MW this winter does not rely on Unit 1”.

Eskom spokesperson Daphne Mokwena said the revised timeline underscores the utility’s commitment to ensure the ongoing safe and reliable performance of South Africa’s only nuclear power station.

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Inspections

Mokwena said that eddy current inspections — a non-destructive testing method used to detect cracks, corrosion, or wear in the metal tubes of steam generators — identified defects on four tubes among several thousand tubes inspected, across two of the newly installed generators.

“Eskom immediately carried out an advanced automated process to address the four tube defects, supported by specialised international teams working alongside local experts. These critical repairs have now been successfully completed to uphold the highest safety and quality standards.

Back to grid

Bheki Nxumalo, Eskom’s Group Executive for Generation, said the planned maintenance underway on Unit 1 will help deliver decades of affordable, low-carbon baseload power.

“Once all maintenance work is complete, Unit 1’s reactor core will be refuelled, tested and synchronised back to the national grid”.

Eskom said to protect the supply, planned outages at Koeberg are carefully staggered every 16 to 18 months so that both units are never offline at the same time.

“Together, Koeberg Units 1 and 2 provide around 1 860MW — approximately 5% of the country’s electricity needs. Unit 2 remains fully operational, generating up to 946MW, with a year-to-date Energy Availability Factor (EAF) of 99.38% as of the end of June 2025.

“The national power system remains stable, with a month-to-date EAF of 62%. As the winter season continues, Eskom encourages all customers to adopt energy-efficient practices,” Eskom said.

Medupi

Last week, Eskom hammered another nail in the load shedding coffin, announcing that Unit 4 of the Medupi Power Station was successfully returned to service eight months ahead of its original schedule.

This has added 800MW to the national grid.

Medupi’s return follows extensive repairs, made possible by the innovative use of a refurbished Generator Stator, an alternative to waiting for a brand-new component.

The unit had been out of service since 8 August 2021, after sustaining significant damage from the explosion of its Generator Stator, a key component in the operation of the generation unit.

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