The balance between wind and solar in Britain’s climate
One of the defining strengths of Britain’s energy system is the complementary relationship between wind and solar. Data from Ember shows that only 2% of days each year experience both low wind and low solar output. Typically, cloudy and windy days balance sunnier and calmer periods, ensuring stable renewable generation across seasons. The contrast between 2024 and 2025 illustrates this dynamic: while 2024 was marked by strong wind and weaker solar performance, 2025 has seen the reverse. The first half of 2025 brought one of the sunniest springs on record, influenced by the unusual positioning of the jet stream, which created settled and bright weather conditions. This natural balance is critical to stabilizing the grid and minimizing reliance on fossil fuels during periods of variability.
Impacts on gas and imports
The surge in solar power has had a significant effect on gas generation. While gas power rose overall in early 2025 to compensate for lower imports from Europe, its role diminished sharply in the spring and summer months. In May, gas accounted for less than 25% of total electricity generation, and by June, this share had fallen further to just 21%, the lowest level ever recorded for that month. Solar and wind together displaced gas during peak demand periods, reducing reliance on costly and carbon-intensive backup generation. Meanwhile, imports from Europe declined by 3 TWh compared to the first half of 2024, due to smaller price differentials between Britain and its neighbors. The ability of domestic renewables to step in underscores the importance of clean energy in ensuring security of supply.
Household and business solar momentum
The solar boom is not only a story of utility-scale projects but also of households and businesses adopting rooftop systems. Domestic-scale solar installations in 2025 reached their highest level in over a decade, driven by falling technology costs and persistently high energy bills. Larger systems are becoming increasingly common: whereas in 2015 only 5% of sub-10 kW systems were in the 4–10 kW range, this share has climbed to 50% by 2025. Regulatory changes are also supporting growth. Under the Future Homes Standard, new homes will be required to include solar panels by default, further embedding solar power into the fabric of Britain’s energy future. On the cost side, solar energy is highly competitive, with Contracts for Difference (CfD) auctions in 2025 awarding solar projects a strike price of £50.07 per megawatt hour (MWh). Onshore wind projects secured contracts at £52.29/MWh, while offshore wind projects came in at £54.23/MWh. This affordability strengthens its role as a mainstream energy source.