Eskom delays Koeberg Unit 1 Return, denies increased loadshedding risk

Eskom has postponed the return of Koeberg Unit 1 to late August from July, citing defects found in four steam generator tubes during routine inspections.

The unit, offline since early 2025 for its long-term operation maintenance, required repairs to meet safety standards set by the National Nuclear Regulator (NNR) for its 20-year life extension granted in 2024. A 72-hour Integrated Leak Rate Test confirmed the reactor’s structural integrity.

Despite the delay, Eskom maintains that loadshedding risks remain unchanged, supported by its Winter Outlook, which projects no power cuts if unplanned outages stay below 13,000 MW. Even at 15,000 MW, loadshedding would be limited to 21 days at Stage 2 over the 153-day winter period. Since mid-May 2025, no loadshedding has occurred, with only 26 hours recorded this financial year. The utility cites progress elsewhere, including the return of Kusile Unit 6 (800 MW) in March and Medupi Unit 4 (800 MW) in July, after a 2021 explosion.

However, Eskom’s year-to-date energy availability factor (EAF) fell to 58.83% from 61.74% last year, driven by a 2.9% rise in unplanned maintenance. Diesel consumption for open-cycle gas turbines also increased, with R5.26 billion spent to generate 892.42 GWh, up from 485.39 GWh in 2024. Koeberg Unit 2, awaiting NNR approval for its own 20-year extension, operates at 946 MW with a 99.38% EAF as of June 2025.