Britain has experienced a record-breaking performance in solar generation during the first half of 2025, according to a new analysis from independent think tank Ember.
The report notes that for 98% of days, Great Britain benefits from either wind or sunshine, providing complementary support to the electricity system.
Despite a sluggish start to the year for wind, solar power surged, increasing by a third compared with the same period last year and reaching a record 9.91 TWh.
Solar generation set new monthly peaks for five consecutive months from March, culminating in a record 14 GW of solar capacity on the grid on 8 July – 44% higher than the previous peak in 2020.
This solar boom helped blunt the impact of low wind speeds, mitigating what could have been a sharp rise in gas-fired generation.
In June, gas accounted for just 21% of electricity generation – the lowest share for that month on record. Nevertheless, gas generation was up overall in the first half of the year to compensate for reduced electricity imports.
Frankie Mayo, Ember’s Senior Energy & Climate Analyst – UK, said: “Solar works for households, it works for businesses and it works for the country.”
“Developing both solar and wind projects is essential to ensure that we have a strong, stable and clean power system year round.”
Ember’s analysis highlights the climatic advantage in Britain, where only 2% of days experience both low wind and low solar generation.
The prevailing meteorological pattern in 2025 saw a sunny, settled spring and summer, partly due to the unusually northern position of the jet stream.
Ember also highlights that energy storage capacity is targeted to double by 2030, indicating a strategic shift towards clean flexibility.
Such tools could reduce reliance on costly gas and biomass backup during rare extended periods of low renewable energy.
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