A Record Solar Year For Great Britain

Progress and pressure points on the UK’s road to clean energy. 

Overview 

Great Britain just recorded its sunniest year in history, with 1622 hours of sunlight up until 15th December’25. Wales saw its sixth sunniest year and Scotland, its second. That’s coming from 2024, probably the dullest year since 1998. 

The sun’s year out in the UK has powered a record year for the country’s solar generation. As of mid December, an estimated 18,314 gigawatt-hours of sun-powered electricity was generated over the year. This makes it a record 6.3% of Great Britain’s power that was supplied by the sun in 2025. Over 50% increase from recent years.

Also behind this massive jump, is an increased solar capacity. 

18% surge in capacity 

According to Solar Media’s Market Research Analyst Josh Cornes, the UK’s solar capacity grew from 20.2 gigawatts to ~23.8GW by the end of the year. This has accounted for much of the rise in solar generation. 

And it was a record year for solar panels on rooftops, with about 250,000 installations reported to the Microgeneration Certification Scheme. Much of this growth is linked to new housing projects, where solar panels are installed as standard. 

A cleaner energy mix 

These numbers show a wider push for cleaner electricity in the country. Great Britain’s electricity supplies averaged only 126 grams of CO2 per kWh in 2025, down from 444g of CO2 in 2009. That’s their second lowest carbon intensity ever. 

Energy Minister Michael Shanks said: “Solar is one of the cheapest forms of power–getting us off fossil fuels and delivering energy security so we can get bills down for good. The sunniest year on record highlights the huge opportunity we have to make the most of this clean energy source and keep installing more solar panels on schools, hospitals and homes.”

“As we move into 2026, we will scale up the solar power we need to shield households from volatile fossil fuel markets and tackle the climate crisis,” he added.

The 2030 goal 

Under its “clean power” target, the government aims to use hardly any polluting gas for electricity by 2030. This is also part of its pledge to bring energy bills down by £300 in that time. The path for renewable energy is certainly set. In 2025, wind, solar, hydro and biomass generated over 127 TWh of electricity in Great Britain, according to BBC analysis of provisional Neso data. 

Yet challenges remain. Because while behind renewables, electricity from fossil gas also saw a slight increase in 2025. “There’s still a significant number of periods in the year where the sun’s not shining, the wind’s not blowing, demand is high […] and that’s where the system is sort of forced to rely on gas-fired power to turn up and meet demand,” notes Pranav Menon, research senior associate at the Aurora Energy Research think tank.

And on paper, it spells trouble for the electricity grid to cope with all the new, clean energy that could be generated. It’s safe to assume that optimal battery storage and grid upgrades will prove essential in addressing the delivery challenges that stand between the UK and its clean power target.