Great Britain’s electricity system is prepared for summer

Managing the electricity system over the summer months is a different challenge to winter. During winter, we see an increase in demand for electricity with colder weather and the nights drawing in earlier, meaning we must ensure there’s enough power produced to meet demand. Last year, we saw the highest winter margins in six years, with our system remaining one of the most reliable in the world.  

In summer, however, the challenge is sometimes the opposite: at times we see lower demand for electricity as warmer weather and brighter days change consumer habits and increase solar generation. Already this year Great Britain has broken two maximum solar generation records. The latest record on 7 April saw the sun generate 14,414 megawatts (MW) of electricity between 12:30 and 1pm, that's enough to power approximately 11 million homes. The growth of smaller, local electricity producers will also reduce reliance on large power stations on the national network. 

In this year’s Summer Outlook, you can find out how we expect secure and reliable electricity supplies and see the new tools we’re introducing to manage those periods of surplus electricity supply.  

One of the most notable additions to our operational toolkit is the updated Demand Flexibility Service (DFS). Since its introduction in winter 2022/23, homes and businesses had been able to take part in flexibility events where they would reduce their electricity usage during periods of forecasted low electricity margins. For the first time ever this summer, homes and business will be able to increase their electricity use during periods of excess supply, supporting both system resilience and efficiency. That means getting rewarded for running appliances such as washing machines or dishwashers during periods of excess supply if you’re signed up with your energy supplier or third-party apps. 

A secure system isn’t all because of flexibility though. The potential for periods of surplus electricity has been a growing trend over recent years. Since 2019 we’ve been redesigned how we manage Great Britain’s national electricity network, putting tools in place to manage the system and keep it secure when spikes in demand occur or when electricity supplies from lower carbon sources are abundant. These tools include a suite of new services providing the system stability and voltage support traditionally provided by power stations.  

By using smaller, flexible technologies to deliver these services – including wind farms, solar and batteries – we’re able to fine tune supply and demand and maintain security at the same or lower cost than before. 

Growth of renewable generation at both national and local levels, combined with favourable expectations for electricity needs in Europe, means that there will be periods where electricity supply exceeds demand this summer. These periods of excess electricity will be efficiently managed using new tools, ensuring the system remains resilient and that surplus electricity isn’t wasted. 

To be absolutely clear, we’re confident that we have the right tools and operational strategies in place to manage the electricity system this Summer. Where necessary, we may issue a Negative Reserve Active Power Margin (NRAPM) notice. 

This is a standard operational measure, informing the energy market that they will need to be more flexible in how they produce electricity, to provide our control room with additional options for balancing supply and demand.   

As ever, we’ll continue to monitor risks closely and work with strategic partners to ensure the electricity system remains resilient. Preparations for Winter 2026/27 system operation are already underway. NESO will share an Early View of Winter 2026/27 report with the industry in Summer. ​  

Dr Deborah Petterson, Director of Resilience and Emergency Management, NESO: 

“The work of our excellent engineering teams at NESO means our energy system is well adapted to support a clean, resilient future, and puts us in a strong position to manage the changing patterns of electricity use over the summer.  

Tools such as the Demand Flexibility Service not only reward consumers and businesses for flexible electricity use but also strengthen the resilience and efficiency of Great Britain’s electricity network.” 

Summer Outlook