Analysis: UK solar power hits record high over summer 2026

UK solar power production hit a new record during the summer of 2026, according to fresh analysis by Carbon Brief. Collectively, solar farms and rooftops generated 8.8 terawatt-hours (TWh) of electricity from June through August, as illustrated in the accompanying chart. Chris Hewett, chief executive of the Solar Energy UK trade association, attributed the record to clear skies and ongoing expansion of solar installations.

This increase took place amid the warmest summer on record in the UK, characterized by five heatwaves from May to August. The summer of 2026 ranked as the sixth sunniest on record, with over 620 hours of sunshine, as reported by the Met Office. England and Wales, particularly hit by extreme heat, experienced their second-sunniest summers on record.

June 2026 became the hottest June in England since records began in 1884, while Wales and the UK as a whole saw their second-warmest June. Wales witnessed its driest July since records began in 1836, with some London areas experiencing no rainfall at all. The temperature peaked at 38.1C at Kew Gardens in London on August 13. Climate change made this summer's record mean temperature 130 times more likely.

Solar generation rose by 23% from the same period in 2025, surpassing levels from the summer of 2021 by double. While solar panels can be impacted by extreme heat, longer daylight hours and higher irradiation more than compensated for any efficiency losses. Each of the summer months saw new monthly records for solar generation. July alone set the highest solar generation in a calendar month ever, meeting 15% of overall electricity demand for the month.

By the end of August, total UK solar generation in 2026 reached 17TWh, a 13% increase compared to the same point in 2025. Domestic rooftop solar accounts for approximately 29% of total capacity. As of the third quarter of 2025, UK solar capacity had reached 21 gigawatts (GW), an 18% year-on-year increase, as reported by the UK government in January.

The University of Sheffield estimates the installed solar capacity to be nearly 24GW, including nearly 172,000 solar installations installed across the UK since the start of 2026. In July alone, over 19,800 rooftop solar panels were installed, averaging one installation every two minutes. Nearly 1.7 million households in the UK now have solar panels installed.

Over 26 heatwave days this summer, UK households with rooftop solar panels avoided an estimated £86.7 million in electricity costs.