NESO: Early view signals secure electricity supply for winter 2026/27

• NESO's Early View of Winter forecasts surplus of 5.5GW (8.8%) over colder months - deemed sufficient and within reliability standard set by government
• Buffer is broadly similar to picture over past two years despite current geopolitical landscape - and higher than during energy crisis of 2022
• Forecast is good news for households and businesses, as Britain continues to have one of the most secure electricity systems in the world.

The National Energy System Operator (NESO) has today (23 June 2026) published its Early View of Winter Outlook, setting out its initial assessment of Great Britain's electricity margins for winter 2026/27.

It signals that the electricity system is expected to remain secure, with a forecast surplus of 5.5GW between 31 October 2026 and 31 March 2027. This represents an 8.8% buffer of peak winter demand, which is in line with recent winters. The loss of load expectation is also well within the government reliability standard.

The outlook reflects detailed and robust modelling of the operational surplus for every day of the winter period. It is based on running 30,000 scenarios, for each day, which stress-tests a range of weather conditions, electricity demand, wind output and other generator availability.

This initial assessment comes against a backdrop of continued disruption in global energy markets. Despite this uncertainty, electricity reserves are expected to be higher than during the 2022 energy crisis, when the system operated securely with smaller margins.

This provides confidence that households and businesses can rely on a secure electricity supply throughout the winter, even during periods of high demand.

Dr Deborah Petterson, Director of Whole Energy System Resilience at NESO, said:

This has been a year of turbulence in energy markets and geopolitical uncertainty, however Great Britain's electricity system has a strong track record of reliability. This early view shows a positive picture for the months ahead, with sufficient electricity margins expected throughout winter.

While we will continue to monitor global energy markets, households and businesses can be confident that electricity supplies remain secure.

The Early View, which will be updated in October, sets out initial electricity margins for the winter. This is the amount of spare electricity available after meeting peak demand, ensuring the system always operates safely and securely.

Whilst the operational view for winter 2026/27 is positive, like all winters there may still be periods of tighter margins during particularly cold weather. 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 electricity system.

These include Capacity Market Notices and Electricity Market Notices, which are used during most winters to signal when additional electricity generation may be needed. 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 Review today, showing that Britain's gas system operated safely and reliably last winter, with gas playing an important role in meeting demand on winter days when electricity demand was highest.

ENDS

About NESO

NESO is Britain's National Energy System Operator. We operate today's electricity system and design tomorrow's energy system. We provide independent, expert advice to plan Great Britain's electricity and gas systems, helping to ensure energy is reliable, clean and affordable.

Notes to editors

• NESO's Electricity Early View of Winter Outlook sets out initial expectations for security of electricity supply on Great Britain's National Electricity Transmission Network.
• Alongside the Early View, NESO has published its Winter Review and Consultation report, which compares the forecasts in the Winter Outlook 2025/26 with actual system conditions during the winter.
• NESO's full Early View of Winter Outlook report is available on its website here.
• Operational surplus refers to the expected amount of excess supply available once demand and reserve requirements have been met. It reflects the availability and reliability of different sources of electricity generation.
• NESO will publish its full Winter Outlook ahead of the winter period, providing updated analysis of expected system conditions.
• The UK Government sets a statutory security of supply reliability standard, requiring a loss of load expectation of no more than 3 hours per year. Our forecast is < 0.1 hrs/year.