Britain's electricity supplies are expected to remain secure throughout winter 2026/27 according to Neso.

After an assessment based on stress-testing 30,000 scenarios for every day of winter, including extreme weather and reduced generator availability, Neso forecasts a 9.5 per cent buffer (5.9GW surplus) above peak electricity demand, which is comparable to recent winters and higher than during the 2022 energy crisis.

In its Winter Outlook, Neso predicted that the electricity system would remain secure in part because of its diverse mix of generation technologies, including battery storage, gas-fired power and wind.

Dr Deborah Petterson, director of whole energy system resilience at NESO, said: “Despite continued geopolitical uncertainty and volatility in global energy markets, Britain enters this winter with a resilient and well-prepared electricity system. Our Winter Outlook shows we have sufficient margins and a diverse mix of generation sources to meet demand, even during periods of colder weather and higher system stress.”

Whilst the operational view for winter 2026/27 is positive, with sufficient surplus throughout, like all winters there may still be periods of tighter margins. During these times, Neso’s control room may use standard operational tools to increase available electricity supply, as part of its year-round, second-by-second balancing of the network. These include Electricity Margin Notices, which are used during most winters as a routine signal when additional electricity generation may be needed to further cushion existing margins. They do not indicate a risk to electricity supplies and are part of the normal operation of a reliable electricity system.

National Gas has also published its Gas Winter Outlook, showing that Britain has sufficient gas supply this winter, with gas playing an important role in meeting demand on winter days when electricity demand is highest.

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