UK Grid Set for Strongest Winter Electricity Margins Since 2019

The National Energy System Operator (NESO) has released its 2025 Early View of Winter, projecting the UK grid’s strongest electricity operational margins since 2019. The report, published on 18 June, outlines the initial outlook for managing the country’s electricity transmission network during the 2025/26 winter period, from 31 October to 31 March.
NESO anticipates an operational margin of 6.6GW, or 10.9% of demand, marking a significant improvement from last year’s forecast of 5.2GW. This margin represents the surplus electricity available to meet real-time demand and maintain reserves, ensuring the network’s safe and continuous operation.
The improved margin is attributed to increased contributions from battery storage, both at the national and local levels, and higher availability of gas-fired generation. Additionally, the commissioning of the Greenlink interconnector between Ireland and Wales has added valuable cross-border capacity.
Despite the positive outlook, NESO cautions that some days may still be tight. Engineers may need to employ standard tools, such as Capacity Market Notices and Electricity Market Notices, to balance supply and demand. These measures are routine and do not necessarily indicate a shortfall.
Dr. Deborah Petterson, Director of Resilience and Emergency Management at NESO, emphasized the need for continued vigilance. “Our early view shows a positive outlook, but we remain committed to monitoring global energy markets and maintaining the network’s resilience,” she said.
A more detailed Winter Outlook report will be published later this year, providing final projections and further operational planning for the 2025/26 season.

Published: 6/17/2025