UK solar generation hit a summer record in 2026 as heatwaves and deployment rose

# What happened Solar electricity generation in Great Britain set a new summer record in 2026. Across June, July and August combined, solar farms and rooftop panels produced 8.8 terawatt-hours (TWh). That total is 23% higher than the same period in 2025 and about twice the generation recorded in summer 2021.

# Why generation rose Two factors drove the increase: weather and more panels.

• Weather: summer 2026 was unusually hot and sunny. The Met Office described it as the hottest on record for the UK, with five heatwaves between May and August and more than 620 hours of sunshine. England and Wales experienced particularly extreme conditions. Longer daylight hours and higher solar irradiation outweighed small efficiency losses panels can suffer at very high temperatures.

• Deployment: installed solar capacity has been growing quickly. UK government figures reported 21 GW by Q3 2025, while a University of Sheffield estimate put installed capacity near 24 GW by 2026. Domestic rooftop systems account for about 29% of total capacity. Nearly 172,000 installations were fitted since the start of 2026, and almost 1.7 million households now have solar panels.

# Monthly and yearly context Each summer month set new monthly records, with July producing the highest-ever monthly generation: 3.3 TWh, which supplied around 15% of electricity demand in July. By the end of August 2026, total UK solar generation for the year stood at 17 TWh, 13% higher than at the same point in 2025.

# Economic effects for households and the grid Households with rooftop solar and batteries benefited directly. Analysis by Utility Bidder estimated that during 26 heatwave days this summer such households avoided about 86.7 million in electricity costs. Chris Hewett, chief executive of Solar Energy UK, said clear skies and continued deployment drove the record and that daytime solar reduced the need for gas generation, helping to keep overall power prices lower than they would otherwise have been.

# Capacity versus generation

# Geographic and data scope The numbers in this analysis refer to Great Britain (England, Scotland and Wales). Northern Ireland is on a separate all-Ireland electricity system and is not included in these figures.

# Short takeaways Solar in Great Britain delivered a record summer in 2026 because an unusually sunny, hot season coincided with rapid capacity growth. The result was higher monthly and seasonal generation, tangible household savings during heatwaves, and a meaningful contribution to daytime electricity demand in July.