Four UK nuclear reactors that were shut down for safety reasons may not be back online until the end of the year, EDF Energy has said.
The reactors at the Heysham 1 and Hartlepool power stations were shut in August following a routine inspection.
EDF said there could be a “phased return to service between the end of October and the end of December, 2014”.
Earlier this week National Grid announced it was seeking emergency supplies of electricity this winter.
It cited concern over potential shortages of power.
BBC industry correspondent John Moylan said that today’s announcement from EDF means “up to a quarter of the nuclear fleet being offline as the UK enters winter”.
All four reactors were closed after inspections found a crack in one of the boilers. The other three reactors were closed as a precautionary measure because they were of the same design.
EDF said on Thursday that it had now had time to assess any work and draw up a timetable.
“Dates for returning the stations to service depend on the findings and completion of the inspections,” the company said.
“Depending on the progress of the programme and any necessary modifications, the company expects there to be a phased return to service between the end of October and the end of December, 2014.
Any re-entry into service will have to be approved by the nuclear safety regulator, EDF said.
On Tuesday, National Grid, which runs the power distribution network, said it was seeking additional electricity supplies for winter.
The company said it was accelerating an emergency plan asking providers how much more electricity they could provide to fill a possible shortfall.
After Thursday’s announcement from EDF, National Grid said: “We have already taken the sensible precaution to tender for Supplementary Balancing Reserve this winter, owing to uncertainty over plant availability.
“The tender process – which does not specify volumes – is sufficiently flexible to cater for any new information from the market.”
EDF, owned by the French government, has other nuclear power stations in the UK: Hunterston and Torness in Scotland, Heysham 2 in Lancashire, Dungeness B in Kent, Hinkley Point B in Somerset and Sizewell B in Suffolk.
Source: BBC News