Carbon Brief’s annual analysis of energy use in the UK has revealed that in 2025, renewables were the UK’s largest electricity source for the first time, providing 47% of the total.
Wind power was the largest contributor to the renewable’s contribution, making up 57.2% of its total, while the fact that 2025 was the sunniest year on record was reflected in an exceptional contribution from solar power, whose contribution grew 31%.
2025 was the UK’s first full year without any coal power, following the closure of the nation’s last coal plant in September 2024.
Behind the contribution from renewables was gas (28%), nuclear (11%) and net imports (10%).
However, while wind, solar and biomass generation all hit record highs, there was also a 5% rise in gas generation. This increase, alongside nuclear power output falling to its lowest level in half a century meant emissions per unit of electricity rose by 2%, stalling the decarbonisation of the grid.
The driver behind the increased reliance on gas was a shift in electricity demand. After two decades of consistent decline, UK demand grew for the second consecutive year, rising by 1% to 322TWh. This reversal signals the long-predicted ‘electrification’ of the economy, driven by surging numbers of electric vehicles, heat pumps and energy-hungry data centres connecting to the grid.
The National Energy System Operator (NESO) did set new records for low-carbon operation, running the transmission grid on 97.7% zero-carbon power for half an hour in April. Yet, it missed its target of a full 30-minute period with no fossil fuels in 2025.
Analysts warn that the challenges of 2025 highlight the scale of the task ahead to meet the government’s target of 95% low-carbon electricity by 2030.
The existing nuclear fleet is set to retire rapidly this decade, and while new offshore wind farms like Dogger Bank are coming online, the pace of renewable rollout must accelerate dramatically to simultaneously replace retiring plants and meet soaring new demand from electrification.
‘The data for 2025 shows hints that this turning point for electricity demand may finally be taking place,’ the Carbon Brief analysis notes, pointing to an additional 2TWh of demand from new EVs alone. With data centre growth adding further uncertainty, the UK’s clean power ambitions now hinge on a race between deploying renewables and the accelerating electrification of transport and heat.
The full analysis can be read here.
Photo: josealbafotos
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