NESO publishes Summer Outlook

NESO has published its annual Summer Outlook today, setting out how Great Britain’s electricity system is expected to operate over the warmer months this year. Headlines:

• Despite the geopolitical backdrop, we remain confident in the security and resilience of electricity supply this summer.  
• Low demand in summer is expected and planned for in an electricity system in transition.
• We have a range of tools at our disposal to respond to changing conditions.  

Many of us look forward to the warmer weather and longer days that summer brings. For NESO, summer brings a different set of operational challenges to winter — not because of risk to supply, but because of how electricity is produced and used at different times of year.  

Comparing winter and summer

In winter, electricity demand is high due to colder weather and shorter, darker days. NESO’s focus is therefore on ensuring enough generation is available to meet that demand. Last winter, the system performed strongly, with the highest winter margins in six years and reliability among the best in the world.

In summer, demand is typically lower because:

1. Consumers use less electricity (e.g. less heating and lighting)
2. More electricity generated locally by homes and businesses (e.g. solar panels, batteries)
3. Electricity generation from wind and solar can be high (GB broke two maximum solar power records last week)

This means that at times, electricity generation can exceed demand. These are normal features of a modern electricity system with increasing levels of clean power. NESO manages this balance in real time to keep the system secure.

NESO’s summer toolkit

What’s in your summer bag? Suncream, sunglasses, water?  

At NESO’s Electricity National Control Centre, we have a range of established tools to balance supply and demand during the warmer months.

These include exporting electricity to neighbouring European countries via interconnector cables, storing energy in batteries or hydro-electric systems, and working with generators to adjust their output where needed. These actions ensure the system remains stable under all conditions.

Rewarding flexibility

There are times in summer, particularly over sunny, windy weekends and bank holidays, when demand is especially low. At those times, NESO is now able to reward consumers and businesses who increase their electricity via our updated Demand Flexibility Service.  

This could mean include running household appliances or charging electric vehicles when there is excess electricity available. This makes better use of clean electricity already being generated, while allowing participants to benefit directly from their flexibility.

Maintaining system stability

If demand is very low this summer, one of the tools available is for NESO to issue a Negative Reserve Active Power Margin (NRAPM) notice.

This standard operational tool is a market signal to notify generators that they may need to reduce output and helps to maintain system stability under a wide range of operating conditions.

Looking ahead

The Summer Outlook sets out our detailed expectations for electricity supply and demand over the coming months. We remain confident that Great Britain’s electricity system is secure, resilient, and well prepared for the summer period. These conditions reflect a system in transition — and one that is being actively managed to ensure it continues to deliver reliable, efficient, clean electricity.