The National Energy System Operator (NESO) has published its Winter Outlook, setting out that despite turbulence in international energy markets, Great Britain’s electricity margins are sufficient for the forthcoming winter.
The electricity system is expected to remain secure, with a forecast surplus of 5.9 GW, representing a 9.5% buffer of peak winter demand. This is in line with its preliminary assessment earlier in the year, and broadly similar to winter 2025/26, it said. The forecast remains “comfortably within the government’s reliability standard” it added.
Britain’s electricity system is supported by a diverse mix of generation technologies, including battery storage, gas-fired power and wind, which provide resilience and flexibility during periods of high winter demand.
The Winter Outlook includes new and improved modelling of the surplus electricity available for every day between 31 October 2026 and 31 March 2027. NESO uses 30,000 scenarios for each day of winter, stress-testing different weather conditions, electricity demand, wind output and other generator availability.
Its report comes against a backdrop of continued disruption in global energy markets, with the ongoing conflicts in the Middle East and Ukraine pushing energy prices higher. Despite this uncertainty, Britain’s surplus is expected to be higher than during the 2022 energy crisis, when the system operated securely with smaller margins, it said.
The Winter Outlook sets out a forecast of electricity margins for the winter, which is the amount of spare electricity available after meeting peak demand. It supports industry preparation and operational planning for the season ahead.
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, it said. 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.
NESO works closely with stakeholders across the energy industry to assess whole-system interactions, monitor market conditions, track global events and identify emerging risks. This ensures Britain’s electricity system is prepared for the coming winter and resilient to the challenges it may face.
National Gas has also published its Gas Winter Outlook today, 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.
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.
“While we never take resilience for granted, households and businesses can be confident that Great Britain’s electricity system remains secure, reliable and among the most resilient in the world.”
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