Eskom has reconnected Unit 1 of the Koeberg Nuclear Power Station to South Africa’s national grid, restoring 930 megawatts (MW) of generation capacity following a major maintenance shutdown.
In a media statement on Wednesday, the utility said the unit was successfully connected to the grid, a project aimed at strengthening baseload generation and improving energy security.
Eskom explained that this was the first scheduled long-term maintenance outage for Unit 1 since the completion of its Steam Generator Replacement Programme in 2023.
“Eskom has reconnected Unit 1 at the Koeberg Nuclear Power Station to the national grid at 01:36 on 29 October 2025, marking an important milestone in further enhancing the security of South Africa’s electricity supply and returning 930MW,” the statement read in part.
The initiative involved detailed inspections, safety assessments, and a 10-year Integrated Leak Rate Test (ILRT) to verify the containment building’s structural integrity and leak-tightness in line with international nuclear safety standards.
Koeberg’s current power contribution
According to Eskom, both Koeberg Unit 1 and Unit 2 are now operational, with Unit 1 ramping up to full capacity and Unit 2 currently generating 941MW.
The utility stated that once it is fully optimised, the two units will jointly contribute over 1,860MW, representing roughly 5% of Eskom’s total generation capacity.
Eskom noted that maintenance on both units is staggered every 16 to 18 months to prevent simultaneous outages and ensure steady supply.
“Both Koeberg Unit 1 and Unit 2 are currently online, with Unit 1 in the process of ramping up and Unit 2 generating 941MW. Once Unit 1 reaches full output, the two units will jointly provide over 1 860MW of capacity to the national grid,” the utility stated.
What you should know
Koeberg, Africa’s only nuclear power plant, began operations in 1976, with Unit 1 and Unit 2 connected to the grid in 1984 and 1985 respectively.
It plays a key role in South Africa’s Integrated Resource Plan (IRP 2025), which recognises nuclear energy as a sustainable part of the country’s long-term energy strategy.
- Eskom had planned for Unit 1 to return to service by July 2025. However, detailed inspections uncovered defects in four tubes within the newly installed steam generators, pushing the timeline to August 2025.
- After completing the steam generator project in November 2023, the National Nuclear Regulator (NNR) extended Unit 1’s licence to operate until July 2044, securing two more decades of safe operation.
- The NNR is expected to decide on Unit 2’s 20-year long-term operating licence by November 9, 2025.
Koeberg provides about 5% of South Africa’s total electricity, making it one of Eskom’s most reliable assets.
The reconnection is expected to provide a boost to South Africa’s strained power grid, adding clean and stable baseload capacity amid ongoing load-shedding and infrastructure challenges.
