Solar power generation in the UK reached a new record over the summer of 2026, as temperatures across the nation soared, according to new analysis by Carbon Brief.
Collectively over June, July and August, solar farms and rooftops generated 8.8 terawatt-hours (TWh) of electricity in the UK*, as shown in the chart below.
Speaking to Carbon Brief, Chris Hewett, chief executive of trade association Solar Energy UK welcomed the new record, adding that it was driven by “clear skies and continued growth in deployment”.
This surge in generation took place amid the hottest summer on record in the UK, with five heatwaves between May and August.
Summer 2026 was the sixth sunniest on record, with more than 620 hours of sunshine, according to the Met Office. England and Wales – which experienced the most extreme heat – saw their second-sunniest summers on record.
June 2026 was the hottest June in England since records began in 1884, according to Met Office data, while Wales and the UK as a whole experienced their second-warmest June.
It was the driest July for England and Wales since records began in 1836, with some parts of London seeing no rain at all in the month, while Wisley in Surrey had no rain for 62 days.
In England, temperatures peaked at 38.1C at Kew Gardens in London on 13 August.
According to the Met Office, this summer’s record mean temperature was made 130 times more likely by climate change.
Amid these hot and sunny months, solar power generation increased 23% from the same period in 2025. This is double the level of solar generation over the summer of 2021, according to Carbon Brief analysis.
While solar panels can be affected by periods of extreme heat, the longer hours of daylight and higher levels of irradiation over the summer more than offset any efficiency losses.
June, July and August all saw solar set new monthly records for solar generation – July saw the highest solar generation in a calendar month ever, with 3.3TWh meeting 15% of overall electricity demand for the month.
As of the end of August, the total UK solar generation in 2026 stood at 17TWh – 13% higher than the same point in 2025.
The number of solar farms and rooftop installations has grown substantially in recent years, helping to boost generation. Domestic rooftop solar accounts for around 29% of total capacity.
In 2025, the UK’s solar capacity reached 21 gigawatts (GW) by the third quarter of the year, according to UK government figures. This is a jump of 3GW, or 18%, year-on-year, as Carbon Brief reported in January.
(Capacity is the maximum output possible from an electricity generation, whereas generation is what was produced over a certain time period, such as a day, month or year.)
According to the University of Sheffield, the installed solar capacity is now nearly 24GW.
This includes nearly 172,000 solar installations that have been fitted across the UK since the start of 2026, according to recent government figures. In July alone, more than 19,800 rooftop solar panels were installed – the equivalent of one installation every two minutes.
In total, nearly 1.7m households in the UK now have solar panels installed.
Over 26 heatwave days this summer – periods of at least three days when temperatures exceed the Met Office’s county-level heatwave temperature threshold – UK households with rooftop solar panels avoided an estimated £86.7m in electricity costs, according to analysis by Utility Bidder.
Talking about the surge in solar generation this summer, Hewett says:
“[It] not only kept bills down for people with solar and batteries in their homes, but helped keep overall power prices much lower than they would have been if Britain had been relying on more gas generation during the day”.
Despite the record generation, no new half-hourly solar power output record was set in the summer of 2026. This still stands at 15.2 megawatts (MW) on 23 April 2026.
* This article refers to the UK throughout, but strictly relates to the island of Great Britain, made up of England, Scotland and Wales. Northern Ireland is part of the separate, all-Ireland electricity system.
Facts Only
* Solar power generation over June, July, and August 2026 totaled 8.8 TWh in the UK.
* This generation was driven by clear skies and continued growth in deployment.
* The summer of 2026 included five heatwaves between May and August.
* Summer 2026 was the sixth sunniest on record, with more than 620 hours of sunshine.
* England and Wales experienced their second-sunniest summers on record.
* June 2026 was the hottest June in England since records began in 1884.
* July 2026 was the driest month for England and Wales since 1836.
* The mean temperature for this summer was made 130 times more likely by climate change.
* Solar power generation increased 23% from the same period in 2025.
* Total UK solar generation by the end of August 2026 was 17 TWh, which is 13% higher than the same point in 2025.
* Domestic rooftop solar accounts for around 29% of total capacity.
* Installed solar capacity reached nearly 24 GW as of the end of 2026, including nearly 172,000 installations since the start of 2026.
* In July 2026 alone, more than 19,800 rooftop solar panels were installed.
Executive Summary
Solar power generation in the UK reached a record of 8.8 terawatt-hours (TWh) over the summer of 2026, driven by clear skies and continued deployment, according to Solar Energy UK. This surge occurred during the hottest summer on record for the UK, which included five heatwaves between May and August. The period saw June, July, and August all setting new monthly records for solar generation; July recorded the highest solar generation in a calendar month ever, accounting for 3.3 TWh and meeting 15% of overall electricity demand for that month.
The environmental conditions were extreme: the summer was the sunniest on record with over 620 hours of sunshine. England and Wales experienced their second-sunniest summers on record, while July was the driest for England and Wales since 1836, with some areas experiencing no rain. Despite periods of extreme heat affecting solar panels, longer daylight hours and high irradiation compensated for potential efficiency losses.
In terms of capacity and installation, total UK solar generation by the end of August 2026 reached 17 TWh, which is 13% higher than the same point in 2025. Domestic rooftop solar accounts for approximately 29% of total capacity. Capacity reached 21 GW by the third quarter of 2025 and nearly 24 GW as of the end of 2026, including nearly 172,000 installations. This increased deployment helped households with solar panels avoid an estimated £86.7m in electricity costs over 26 heatwave days.
Full Take
The narrative connects record solar output directly to extreme climatic events, framing renewable energy not just as an environmental solution but as a crucial defense mechanism against unprecedented heat. The pattern observed is the amplification loop: hotter, sunnier weather encourages greater adoption and performance of solar technology, which in turn contributes to mitigating costs during periods of high demand or reliance on traditional generation. The fact that record generation occurred alongside record heat suggests a critical interplay where physical environmental stress intersects with technological response.
The increase in capacity (13% higher than 2025) and installation rate demonstrates systemic growth driven by accessible technology and incentives, rather than solely the weather anomaly. However, the focus remains heavily on the positive outcome—cost avoidance for households—while downplaying potential thermal limitations or grid infrastructure strain that may accompany such peak generation. The dismissal of the lack of a half-hourly power output record suggests a focus on aggregated annual/monthly totals over granular temporal performance.
The implication is that technological proliferation can act as a buffer against environmental volatility, but this resilience depends entirely on the stability of the underlying physical conditions and policy frameworks. Further inquiry must address whether the growth in capacity and installation scales proportionately with the increased thermal stress across all regions, and how infrastructure handles the peak demands suggested by record generation figures. What are the long-term consequences when technological optimization becomes inseparable from climate extremes?