
NESO data for 2025 reveals solar generation in Great Britain up almost one third on the previous year.
Image: Alev Takil, Unsplash
Solar generation accounted for 6.3% of Great Britain’s power in 2025, according to mid-December data from grid operator NESO. The new record was a result of increased deployment and favorable weather conditions.
NESO data to Dec. 16 records 18,314 GWh of generation from solar in 2025, up 30% on the 14,067 GWh of solar generation recorded in 2024.
The significant increase was in part driven by increased capacity. Government figures to the end of October 2025 recorded 1.9 GW of new deployed solar capacity added over the previous 12 months, up 10.4% to a total of 20.7 GW. These figures are provisional and likely to be revised upward as further data is received on operational sites. Deployment in 2025 also included record numbers of new rooftop installations, with the previous record from 2011 broken in early November.
Increased sunshine hours in 2025 played a role, too. UK national weather service The Met Office recorded record-breaking weather in 2025, with 1,622 hours of sunshine recorded for the year as of Dec. 15. This is more than any year since records began in 1910, eclipsing the previous record that had stood since 2003.
Spring was a particularly strong season for irradiance with 653 hours of sunshine recorded over March, April and May – 43% above average.
Chris Hewett, chief executive of Solar Energy UK, said the solar sector was no longer a “bit-player” in the UK energy market, noting it now supplies six times more generations than hydropower and more than half the output of nuclear.
“With capacity set to rise to almost 60 GW over the coming decade, we are guaranteed to see records tumble each year, putting the nation on course for cheaper, cleaner power,” Hewett said.