Eskom has decided to defer the replacement of steam generators at unit 2 of its Koeberg nuclear power station, owing to concerns it will worsen an energy crunch, senior officials said on Friday.

Unit 2 was taken offline in January for five months during scheduled refuelling and maintenance, when the three steam generators were also meant to be replaced as Eskom seeks to extend the lifespan of the country's only commercial nuclear plant.

“There is a high risk now that the unit being returned to the grid will be later than currently planned for,” Jan Oberholzer, COO at Eskom said.

“Due to the potential severe impact of returning this unit later than the end of June ... we made a decision then to defer the steam generator replacement work and scope to the next outage,” to August next year, he said.

SA faces regular electricity cuts, as an ageing grid powered mainly by ageing coal-fired plants prone to breakdowns has cost Africa's most industrialised economy billions of dollars