British solar power surges past 2024 total
Good weather and rapidly proliferating farms mean solar generation is at record levels
Solar power generation in Britain so far this year has surpassed the total for 2024 as panels are rapidly installed and amid favourable weather, underlining renewable energy’s increasing importance to the grid.
Some 14.08 terawatt hours of electricity was produced from solar in Great Britain by August 16, about one-third higher than at this time last year, a Financial Times analysis of University of Sheffield data has found. This is enough to power 5.2mn homes for a year, or the London Underground for more than a decade.
The figures underline the momentum of Britain’s clean energy push, but also make it more important that the grid can cope with greater variable power sources.
A rapid build-out of solar technology, with capacity increasing by a fifth since 2023, had allowed the UK to make the most of ideal weather conditions throughout much of the spring and summer, analysts said.
“Despite the UK’s reputation for gloomy weather, solar has been unstoppable in 2025, thanks to a powerful combination of very sunny weather and record capacity on the system,” said Josie Murdoch, policy analyst at energy think-tank Ember.
For one half-hour period on July 8, solar output was a record 14 gigawatts, meeting almost 40 per cent of Britain’s electricity demand during that period, according to the National Energy System Operator (Neso). Between January and July, solar supplied about 10 per cent of England and Wales’ electricity.
Energy minister Miatta Fahnbulleh said the findings were “a clear sign that our clean power mission is working”, and that the solar rollout would help lower energy bills, tackle the climate crisis and reduce the UK’s reliance on “volatile fossil fuel markets”.
The government aims to increase UK solar capacity to 45-47GW by 2030 in order to meet its goal of 95 per cent of generation coming from clean power sources by then.
It has unveiled a number of policies to encourage further investment, such as requiring new homes to have rooftop panels, funding for schools and hospitals to install solar and lengthening subsidy contracts for developers.
Changes to planning law will allow mid-sized projects of 50-100 megawatts capacity to be approved at local rather than national level.
Neso is also overhauling the grid connection process in an effort to prioritise clean power schemes and remove “zombie” projects with little hope of ever being built.
The move came after the developers of some proposed solar schemes had been told they would not be connected to the grid until the late 2030s. Neso said the change would “allow us to connect clean energy projects more quickly, creating a better environment for private investment”.
Investment by developers has nonetheless resulted in a big ramp-up in solar plants over the past five years, government data shows. Of the 18.1GW of solar capacity online in the UK as of the end of March, more than 12.4GW was supported by some government subsidies and 5.6GW was not.
Industry says the total capacity is higher than official government figures, at about 22GW.
In addition, since December 2021, solar developers have won government support deals — know as contracts for difference — covering about 7GW of new projects that are still being built. Long-term deals to supply specific big electricity customers are also becoming important sources of funding.
“There’s no question that solar is the cheapest form of power generation so there’s a real optimism for the economic opportunity,” said Chris Hewett, chief executive of trade body Solar Energy UK.
Developers are also increasingly looking to install batteries alongside solar farms, so as to allow a constant supply of power. This has been enabled by falling costs of batteries in recent years because of supply from China.
“There’s an enormous number of people wanting to build large scale solar-plus-battery projects,” said Adam Bell, policy director at advisory group Stonehaven. “Essentially, you produce solar during the day, you store it in the battery and you sell it at the winter peak. There’s very little not to like . . . the future for these projects is enormous.”
Bell added: “As costs continue to decline . . . it’ll just make more sense to install more and more until electricity during the middle of the day becomes essentially free as it already nearly is in Spain.”
Others question whether the UK can realistically double its solar capacity in just five years, as the government intends. Developers have warned of grid bottlenecks, local opposition to huge solar farms and international competition for skilled workers and equipment.
“It’s a huge, huge challenge,” said Keith Gains of Quinbrook Infrastructure Partners. The investment firm owns the UK’s largest solar farm, Cleve Hill Solar Park in Kent, which started supplying power to the grid this year.
With half a million solar panels over 900 acres and a capacity of 373MW, at peak output Cleve Hill can meet about 0.7 per cent of the country’s electricity demand.
But the development process took roughly 10 years, with three of them taken up by planning approvals. The project faced fierce opposition from locals over the scale of the facility and potential biodiversity loss.
“By our reckoning, we think [the UK] needs about 80 projects akin to Cleve Hill. So far, we’ve got one,” said Gains. “They are big projects and there’s a lot of groups of people, aspects [like] wildlife . . . that have to be taken into account.”
If all of the large solar farms of more than 50MW now seeking planning approval or yet to begin construction were completed, the UK would still be a third short of its 2030 goal, according to FT analysis of government planning data.
Reaching the target would also require unprecedented investment in transmission and distribution infrastructure. Variable power sources, such as solar and wind, can make the power system more complicated to manage.
In Spain and some other countries, high solar output has led to an oversupply of power at times, which can send prices negative and even risk blackouts.
Ofgem, the energy regulator, approved up to £10bn for grid upgrades in July, part of a wider £80bn programme of spending to “significantly increase the grid’s capacity, through new power lines, substations and other technologies, to handle the flow of electricity from new renewable sources”.
Solar technology is also becoming more robust and resilient, said Marcel Suri, chief executive of data provider Solargis.
“Years ago, the solar power plant was a relatively simple device which just generated electricity as the sun was shining. Today it’s much smarter. You can build sophistication around reducing power when the grid is full or storing it in batteries . . . It’s unbelievable how many systems are running in the background.”