Britain’s power sector saw record solar generation in the first half of 2025, helping to offset a slowdown in wind output and limiting reliance on gas, according to new analysis from Ember.
Solar generation in the United Kingdom reached 9.91 TWh between January and June, up by one-third compared with the same period in 2024. The 2.4 TWh increase balanced a 2.8 TWh reduction in wind output during the same period.
Wind generation began the year below average but later returned to normal levels, pushing gas to record lows. In June, gas accounted for just 21 percent of electricity generation, one of the lowest shares on record.
Ember’s analysis highlighted how Britain’s renewable mix is naturally complementary, with 98 percent of days in the first half of the year being either windy, sunny, or both —leaving just 2 percent of days with low renewable output from both sources.
Gas use in early 2025 increased temporarily to compensate for reduced imports, driven by shifts in price differentials. However, one of the sunniest springs on record ensured that solar kept gas in check.
“Britain is lucky to have a climate remarkably well-suited to renewables,” said Ember analyst Frankie Mayo. “If a day’s not windy, it’s almost always sunny instead, so either solar panels or wind turbines can be generating power.”
Solar generation set new monthly records for five consecutive months starting in March 2025. On July 8, Britain recorded its highest-ever daily solar output at 14 GW, up 44 percent from the daily peak just five years ago. The surge reflects not only favorable weather but also the rapid rollout of new solar capacity.
Domestic solar installations are now at their highest level in over a decade, supported by falling panel costs and persistently high energy bills. Households are also increasingly installing larger solar arrays, even without the subsidies that ended more than five years ago.
Despite its slow start in 2025, wind remained Britain’s largest clean power source, generating 39 TWh in the first half of the year — about a third of total electricity generation. Last year, wind came close to overtaking gas as the country’s primary power source, providing 29.2 percent of electricity compared to 30.4 percent from gas.
“Solar is having a golden year,” Mayo added. “Britain is benefiting from a recent push in new solar installations, limiting the need for expensive gas when wind speeds were below average. This shows why Britain needs solar alongside wind to guarantee a strong, stable and clean power system year-round.”
Baburajan Kizhakedath