British solar energy generation reached new heights in the first half of 2025, according to analysis by the think tank Ember. The organization reported that solar power produced approximately 9.91 terawatt-hours (TWh) during this period, representing a 33% increase compared to the same period last year. This growth helped offset a decline in wind power, which fell by 2.8 TWh.
The report noted that early in the year, gas-fired power generation increased as imports declined. However, gas generation dropped to record lows in June, providing only 21% of the nation’s electricity as wind speeds returned to average levels.
Ember highlighted the complementary nature of solar and wind energy, stating that “98% of days [are] sunny, windy or both,” underscoring the synergy between the two renewable sources.
Analyst Frankie Mayo commented on the significance of these developments, saying, “Britain is lucky to have a climate remarkably well-suited to renewables. If a day’s not windy, it’s almost always sunny instead.”
Solar generation experienced a series of record months, with five consecutive months of peak production starting in March. Notably, July 8 saw a peak output of 14 gigawatts (GW), marking a 44% increase compared to five years prior.
The growth in solar capacity is attributed to favorable weather conditions and a surge in new installations, as households installed larger systems despite the phasing out of subsidies.
Wind energy remained the largest source of clean power in the UK, generating 39 TWh in the first half of 2025.
Mayo emphasized the importance of solar, stating, “Solar is having a golden year. Britain is benefiting from a recent push in new solar installations, limiting the need for expensive gas when wind speeds were below average.
