National Grid is to pay mothballed plants to be online this winter to prevent power cuts, it has said.
The company, which owns and manages the UK's power grid, said the move was a "sensible precaution" due to uncertainty over the power plants that would be available this winter.
National Grid had set out plans for mothballed or closed generators to bid for payments to be in reserve next winter (2015/16) to cope with the "energy crunch" when the gap between total power capacity and expected peak demand could shrink to just 2%.
It had not planned to run the scheme for this winter, b ut since June - when it announced its proposals - there have been fires at the Ironbridge and Ferrybridge power stations and an announcement that Barking power station was closing.
In addition, EDF has temporarily closed four reactors at Heysham 1 and Hartlepool for investigations over a defect found in one of them, taking enough power to supply three million homes off the system, which may have an impact.
Under the "supplemental balancing reserve" scheme, power generators will bid for payments to be available to provide power at peak times from November to February, with extra payments if they are used, and fines if they are not available when needed.
Cordi O'Hara, National Grid's director of UK market operation, said: "This is a sensible precaution to take while the picture for this winter remains uncertain.
"At this stage we don't know if these reserve services will be needed, but they could provide an additional safeguard."
National Grid also said it had received a positive response to its pilot scheme to pay energy users, such as factories, to power down during peak hours to reduce demand on the system.