The Energy Transition | Renewables generate over half of UK’s electricity for second year, DESNZ reports

This week's edition looks at latest UK energy statistics for 2025 and the creation of a single national flexibility market in Great Britain.

Renewables generate over half of the UK’s electricity for second year, DESNZ reports

Renewable energy has generated more than half of the United Kingdom's electricity for the second consecutive year, according to energy statistics for 2025 published by the Department for Energy Security and Net Zero (DESNZ).

The findings appear in the government's recently published UK Energy in Brief 2026 report that provides an overview of the government's latest annual data on energy production, consumption, pricing and emissions in the UK. 

RenweableUK highlighted that renewables had generated a record annual percentage of clean power in 2025 and outstripped fossil fuels for the fifth time in six years. 

Wind remained the dominant clean power technology at 29.5% of generation, only just behind gas, which led all sources at 31.8%.

Wind and solar

Renewable sources generated 52.1% of the UK's electricity in 2025 compared with 32.3% from fossil fuels, representing a 1.6% and 0.4% increase respectively from 2024 levels. DESNZ attributed the increase in renewable sources to expanded offshore wind and solar capacity and to record levels of sunshine. 

In 2025, the UK experienced its sunniest year since records began in 2001, supporting a 34% rise in solar PV generation to a record 20.1 terawatt-hours (TWh). Solar energy supply also rose by 33% with an increase of 16% in small-scale renewable installations since 2024, bringing the total to nearly 2 million installations.

While onshore wind generation decreased by 1.1% in 2025, offshore wind generation rose by 6.6% and overall wind energy generation rose by 3.4%. 

Total production

Total production of primary oil; natural gas; coal; nuclear; wind, solar and hydro; and bioenergy and waste fell by 0.6% in 2025. Within this, nuclear output fell by 11% to a record low, driven by an increase in outages at the UK's remaining plants.

Oil and gas production are 41% and 24% below pre-pandemic 2019 levels respectively, with total production now 68% lower than its peak in 1999. However, in 2025, fossil fuel generation increased 4% against 2024 figures, due to declining volumes in gas imports.

Emissions fall

DESNZ estimates that UK territorial CO2 emissions decreased by 2% year on year to 284.8 million tonnes in 2025, while total greenhouse gas emissions declined by 1.8%. According to the report, these figures are largely driven by lower gas consumption in industry and reduced coal use in electricity generation.

With the closure of the UK's last coal-fired power station, Ratcliffe-on-Soar, in September 2024, there was no coal-fired electricity generation in 2025, a historic milestone for the sector. 

RenewableUK's chief executive Tara Singh said that the statistics prove that "clean power is right at the heart of our modern energy system, consistently providing most of the electricity we need to keep British homes and businesses up and running." 

NESO unifies national flexibility markets

The National Energy System Operator (NESO) has announced that it is merging the Local Constraints Market (LCM) with the Demand Flexibility Service (DFS) to form a single national flexibility service.

The LCM, launched in 2023, enables NESO to procure flexibility from consumers to absorb excess generation along the England-Scotland network boundary, and manage network constraints, most notably in Scotland, where it has been used to consume surplus wind energy. 

The DFS, which launched in winter 2022-23, is a year-round demand flexibility tool through which households and smaller businesses are incentivised to shift their electricity consumption away from peak demand periods, and/or to when the grid has excess renewable energy. Earlier this year, Ofgem approved a series of amendments to the DFS which, alongside other reforms, allowed NESO to pay consumers to turn up, as well as turn down, their demand. 

NESO plans to absorb the LCM's constraint management capability into the DFS, creating a single market through which providers can access both margin and constraint management opportunities across Great Britain. NESO says that the combined service is designed to encourage growth and wider participation in the flexibility market by replacing two separate arrangements with a single consistent point of contact. The move also aims to widen the geographic scope of constraint management beyond the areas traditionally served by the LCM.

NESO is managing the transition in phases and will continue to run the LCM over the coming months while onboarding existing LCM participants into the new service. No firm and final transition date has yet been confirmed.

This article was written with the assistance of Elise Hill and Maggie Hudson, trainee solicitors