The National Grid said that gas and electricity supplies are enough to see the UK through this winter despite a series of power station closures since last year.
Chris Train, director of market operations, said electricity margins - the difference between peak demand and supply - were tighter than we have seen historically but that there was enough to meet the UK's needs.
However regulator Ofgem says that risks to security of electricity supply - the dangers of the lights not being kept on - are increasing at a worrying rate.
In its 2013/14 winter outlook report, National Grid said its central forecast was for an electricity margin of 5% during peak demand in cold weather.
Margins have been falling over the past few years, blamed on new laws on power station emissions and economic pressure to mothball old gas-fired power stations.