Britain’s electricity supplies expected to remain secure this winter

Britain is expected to have sufficient electricity supplies this winter, with new analysis from Winter Outlook 2026/27 forecasting adequate electricity margins throughout the colder months.

Published today, our Winter Outlook 2026/27 forecasts an operational surplus of 5.9GW, equivalent to a 9.5% buffer above our assessment of peak demand. The assessment concludes that electricity supplies are expected to remain secure throughout the winter period and within the Government's reliability standards, with margins broadly similar to those forecast for winter 2025/26.

Britain continues to benefit from a diverse mix of generation sources, including new battery storage, gas-fired power stations and wind power. Together these sources provide resilience and flexibility during periods of high winter demand.

The Winter Outlook models the expected surplus electricity for each day between 31 October 2026 and 31 March 2027. NESO also uses 30,000 scenarios for each day of winter, stress-testing different weather conditions, electricity demand, wind output and other availability.

Today’s 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.  Britain’s surplus is expected to be higher than during the 2022 energy crisis, when the system operated securely with smaller margins.

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.

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.

While the overall outlook is positive, periods of colder weather can still lead to tighter margins, as is typical during any winter. Electricity system operation depends on a range of factors that can change over time, including weather conditions, generator availability, transmission network constraints and market behaviour. 

In these circumstances, our control room can use established operational tools, including Capacity Market Notices and Electricity Margin Notices, to help balance the system and ensure supplies remain secure. These notices are routine operational tools and do not indicate a risk to electricity supplies.

We work 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.

Winter Outlook