The National Grid says the UK's buffer of electricity supply has risen to 5.5% which it describes as "manageable".
Last winter, the National Grid said overall spare capacity was at 5.1%.
This year's margin includes 3.5 GW of "contingency reserve" which includes paying firms to use less electricity and employing reserve power plants.
In its Winter Consultation Report, the National Grid forecasts that there will be sufficient gas supplies to meet demand this winter.
"The surplus margin for this winter is 5.5%. This is the additional power we expect to have available over and above what is needed to meet electricity demand," said Cordi O'Hara, director of UK system operations at the National Grid.
"We believe the margin is manageable and that we have the right tools and services available, including extra power we can call on if we need it, for times of highest demand."