The UK’s safety margins could halve after the unexpected loss of 3 GW of electricity generation capacity in recent weeks.
The fire-damaged Ferrybridge coal-fired power plant and four of EDF energy’s nuclear reactors, taken offline due to safety concerns, are due to return later this year but delays would increase the risk of a supply shortfall.
“National Grid and Ofgem need to face this challenge to secure supply for this winter, especially ahead of a general election. A lot of ministers will be telling them the same thing,” the former Department of Energy and Climate Change director Jonathan Brearley said.
Brearley, a key architect of the government’s electricity market reform, told Utility Week that EMR would solve such problems in the long-term.
“This is exactly the kind of problem that the capacity market was designed to address but the current decline in supply margins was always going to be a risk as we make the transition to EMR ,” he said.
The winter of 2015/16 was forecast to have the highest risk of blackouts due to the mandatory shutdown of older plants before new capacity is ready to come online. But if the generating units fail to return to service before cold wintry weather sets in, the UK could face similar supply margins a year earlier than expected.
Brearley said the situation is “tight but manageable” if National Grid and Ofgem remain vigilant.
A spokesman for Ofgem told Utility Week: “While no system can ever give a 100 per cent guarantee, householders can be confident that National Grid has the right levers to help keep the lights on.”
National Grid declined to comment on the security of supply situation for this winter before it produces its official winter outlook which is due in October.
“At the moment we are in the consultation stage for our Winter Outlook report for 2014/15,” a spokeswoman for National Grid said.
“Any changes to capacity will be fed into this report and we will continue to keep the situation under close review,” she added.
In Ofgem’s June outlook report the regulator estimated this winter’s peak demand at average weather conditions to be between 54- 55 GW, with a ‘safety net’ of a 5-10 per cent supply margin on top of this.
But this margin could now shrink from an estimate of 5.5GW to just 2.5GW due to the unexpected loss of the nuclear and coal plant capacity, bringing margins in line with the estimated 2-5 per cent forecast for winter 2015/16.
SSE says it expects one of its units to return to service by November at the earliest while the unit most badly affected is only expected to return in March next year.
Meanwhile, EDF Energy has given a mid-October restart date for its nuclear units but industry insiders note that nuclear safety outages typically extend schedules to take a conservative approach to safety.