Solar power in Great Britain has surged to unprecedented levels in the first half of 2025, rising by 32% to generate a record 9.91 TWh, according to new report by Ember. This marks the fifth consecutive month of record-breaking solar generation since March and underscores the country’s rapidly expanding clean energy capacity.

For most days in the year, Britain benefits from either sunshine or wind. In the first half of 2025, a slow start for wind power was offset by exceptionally strong solar output, helping to keep gas generation low. In fact, gas accounted for just 21% of electricity generation in June, a historic low for the month. Overall, gas generation rose slightly in the first six months to compensate for lower electricity imports from Europe.

Ember report shows that only 2% of days experience both low wind and low solar generation, highlighting how well the UK’s climate supports a balanced renewable energy system. While 2025 has been less windy than average, it has been one of the sunniest years on record, with solar generation repeatedly breaking records. On 8 July, the UK hit a new solar peak of 14 GW – 44% higher than the peak recorded five years ago.

Solar growth across households and industry

Domestic-scale solar installations are also seeing a boost. Falling panel prices, rising energy costs, and new government regulations mean that newly built homes will include solar panels “by default” under the Future Homes Standard, which will come into effect before the end of 2025. Larger household installations now make up half of all new domestic solar capacity, a dramatic increase from just 5% in 2015.

Solar power is also economically competitive. In the most recent Contracts for Difference auction, solar came in below £72/MWh, cheaper than both onshore and offshore wind. The UK government has reaffirmed its 2030 solar target of just under 60 GW, supported by a Solar Roadmap outlining 62 measures to triple capacity.

Balancing clean power and reducing gas reliance

The complementary nature of wind and solar has helped stabilise electricity generation across the year. Comparing the first half of 2024 to 2025, the increase in solar generation largely offset a reduction in wind output, demonstrating the value of a diversified renewable system.

Clean flexibility tools, such as energy storage, are increasingly important for managing rare periods of low renewable generation. While gas remains a strategic backup, its long-term use is expected to decline as storage capacity is set to double by 2030, reducing reliance on costly gas and biomass.

Frankie Mayo, Senior Energy & Climate Analyst at Ember, 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 we have a strong, stable, and clean power system all year round.”

With record-breaking solar and balanced renewable generation, the UK is off to a strong start in 2025, highlighting the critical role of clean energy in the nation’s power system.