Great Britain broke a series of records for running its electricity system more cleanly than ever before, the National Energy System Operator (NESO)has announced.
It comes as the operator publishes its Britain’s Energy Explained: 2025 Review, which outlines that 2025 saw renewables (wind, solar, hydro and biomass) produce a record 44% of our electricity (up from 42% in 2024).
This amounts to a total of more than 127 terawatt hours (TWh) of electricity for Britain, which is the highest ever recorded. beating the previous high of 119TWh in 2024. This represents a threefold increase on the 43 TWh generated by renewables in 2015.
Last year also saw NESO run Britain’s electricity grid at 97.7% zero carbon for the first time in history. It happened on 1 April between 15:30 and 16:00, beating the previous record of 95% set on 15 April 2024. Low carbon energy sources produced enough electricity at that time to power around 28 million homes and over 5 million businesses across the country.
It was also the first calendar year without any coal on the system, after Britain became one of the only countries in the world to phase out coal entirely from its electricity network – the first time since the 1880s. Coal had generated as much as 40% of our electricity as recently as 2013.
Wind was not only the biggest source of renewables, but also accounted for the single largest source of electricity generation in 2025 for the second year in a row, at 29.7% – higher than gas, which stood at 26.8%.
But solar was the biggest success story of the year, seeing the biggest single rise, reaching 6.5% across the year – up nearly a third on 2024. This was helped by 2025 being the UK’s sunniest year on record.
Gas was Britain’s second largest source of electricity, providing 26.8% or 77TWh. This was a slight rise from 72 TWh in 2024, which can be accounted for by planned outages at nuclear power stations and rising energy demand.
Electricity demand rose by 3% during 2025, equal to an additional 8 TWh.
Kayte O’Neill, Chief Operating Officer, National Energy System Operator (NESO) said:
“It’s hard to believe how far Britain has come on its clean power journey over the past quarter of a century, with renewables now producing 44% of our electricity in 2025 – up from just 3% in the year 2000.
“Hitting 97.7% zero carbon last year really shows what is possible, and I look forward to seeing if we can break the ultimate record of running Britain’s electricity grid entirely zero carbon in 2026.”
Image from Shutterstock
