Britain's Electricity Generation - December 2025
Fuel Type Breakdown
Britain’s electricity generation in December 2025 was once again led by wind, which supplied 38% of the energy mix. While slightly below the 39% recorded in December 2024 and the 41% peak in December 2023, wind maintained its dominant position and continued to outperform all other generation sources. Wind generation exceeded gas output by 13 percentage points, underlining its central role in Britain’s winter electricity supply.
Gas accounted for 25% of electricity generation in December 2025, its lowest December share in the past five years, and 13 percentage points below December 2021. This continued decline highlights sustained progress in reducing reliance on fossil fuels, particularly during peak winter demand.
Electricity imports rose to 15% of the generation mix, the highest December share over the past five years and up 5 percentage points year-on-year. This increase reflects growing reliance on cross-border electricity flows to support domestic supply during periods of high demand.
Nuclear power contributed 10% to the mix, its lowest December contribution in the past five years and 6 percentage points below both December 2021 & 2022, continuing a multi-year trend of reduced nuclear availability.
Solar generation delivered 2% of electricity, the highest December contribution in the past five years, though still modest given seasonal conditions.
Storage technologies supplied 2% of the mix, doubling their contribution compared to previous Decembers and marking the strongest December performance to date. This growth highlights ongoing improvements in grid flexibility and battery capacity.
Biomass generation accounted for 7%, up from 6% in December 2024, while hydropower remained steady at 3%, consistent with the past three Decembers.
Coal remained absent from the generation mix, reinforcing Britain’s continued phase-out of coal-fired power.
Zero-Carbon Sources & Carbon Intensity
Zero-carbon sources, including wind, solar, nuclear, and hydro, supplied 67% of Britain’s electricity in December 2025. This represents the highest December share in the past five years and an 11 percentage point increase compared to December 2024.
Carbon intensity fell further to 120 gCO₂/kWh, improving on December 2024’s 126 gCO₂/kWh and marking the lowest December level across the five-year period. This reduction reflects the combined impact of strong wind generation, increased storage deployment, and reduced gas usage.
On a rolling 12-month basis, carbon intensity stood at 129 gCO₂/kWh, slightly higher than the previous year’s rolling average but still significantly lower than levels seen earlier in the decade. Meanwhile, the rolling 12-month average for zero-carbon generation increased to 56%, highlighting continued long-term progress in decarbonising Britain’s electricity system.
Concluding Remarks
December 2025 capped off a strong year for Britain’s electricity transition. Wind remained the backbone of the generation mix, and the zero-carbon share climbed to a record December high of 67%. These developments helped drive carbon intensity to its lowest December level in five years.
However, the continued decline in nuclear output and a sharp rise in electricity imports underline ongoing structural challenges. To maintain momentum toward net zero and strengthen energy security, sustained investment in domestic clean generation, nuclear capacity, and flexible technologies will remain essential as Britain enters the next phase of its energy transition.
Britain's Electricity Summary Charts

Monthly Statistics
12-Month Rolling (Average) Statistics
To explore more insights, visit our interactive renewables map
here.
Data source: NESO 2026
(https://www.neso.energy/energy-101/great-britains-monthly-energy-stats)
About the Author
Doug is a specialist in carbon reporting and research, with extensive experience in supply chain emissions, regulatory compliance, renewable energy developments and sustainability performance improvement. He holds a Master’s degree in Green Economy, which underpins his ability to interpret complex environmental data and advise on practical, impactful strategies.
At edenseven, Doug leads the production of the firm’s monthly Britain’s Electricity Generation report, delivering clear, data-driven insights into the UK’s changing energy landscape. His work supports clients in understanding market trends, emissions performance, and opportunities for cleaner energy adoption.
Doug is a Registered Environmental Practitioner (REnvP) and an ISEP Practitioner, reflecting his professional standing and commitment to advancing sustainable practices across sectors.








