The UK Electricity Generation Mix: What Powers the Grid Today

Roughly two-fifths of the electricity reaching UK homes now comes from renewables, about a third from gas, and around a sixth from nuclear. In the year from April 2024 to March 2025, electricity in the UK came from roughly 42.1% renewables, 33.3% natural gas, 16.2% nuclear, 5.9% coal and 2.5% other sources¹. Those are the headline shares, but they are not the whole story: the mix moves hour by hour, season by season, and different official and independent bodies publish different numbers for the same period because they count different things.

The direction of travel is clear. Renewables generated 57% more electricity in the UK than fossil fuels in 2024, a reversal of the position only a decade earlier². Gas remains the single largest fuel when wind output falls, and it has been the dominant fuel used for electricity generation since 2008³. For a household, the practical meaning is that every unit of electricity used is a blend: some wind, some gas, some nuclear, some solar, and the blend in an hour of a still winter evening looks nothing like the annual average.

Why the headline figures vary between publications

The most widely quoted set of figures comes from the fuel mix disclosures that suppliers and consumer bodies publish. For the year April 2024 to March 2025, the UK average fuel mix was 42.1% renewables and 33.3% natural gas⁴, with nuclear at 16.2%, coal at 5.9% and other sources at 2.5%¹.

Other reputable bodies publish different numbers for broadly the same period, and the differences are real rather than errors. A Commons Library briefing on 2024 generation states that 51% was from renewable sources such as solar and wind power, and 14% from nuclear energy⁶. Nesta, describing how UK electricity demand is met, gives around 38% renewable sources, 15% nuclear, 7% biomass and 30% fossil gas⁷. Carbon Brief's analysis of 2024 puts nuclear at 41TWh, or 13% of generation².

Three things explain the spread. First, the measurement period differs: the April-to-March regulatory year used for fuel mix disclosures does not line up with the calendar year used in statistical analyses. Second, some figures describe electricity generated in the UK while others describe electricity supplied to consumers, which includes imports over interconnectors. Third, some statistics count only Major Power Producers, a defined subset of generators, while others count all generation including small rooftop solar that never passes through the transmission system.

The scale of the system also matters for context. The UK generated 285 TWh of electricity in 2024, down from 294.1 TWh in 2023 and 319.7 TWh before that⁵. Falling total generation alongside a rising renewable share means the gas and coal slices are shrinking from a smaller pie as well as a smaller proportion of it.

Shifts in the mix since 2012

The change over a little more than a decade is stark. In 2012 the UK fuel mix was 39.3% gas, 27.5% nuclear, 19.4% coal, 11.3% renewables and 1.5% oil, with 1% from other sources⁸. Renewables were the fourth-largest source. Today they are the largest.

By 2019, gas had reached 46% of electricity generated, with renewables at 23% and nuclear at 27%⁹. The renewables figure more than doubled again between 2014 and 2024, from 65TWh to 143TWh, a rise of 122%². In 2024, renewables generated 57% more electricity than fossil fuels², and the UK generated 10.85% less electricity overall than in 1990, with over a third of that energy generated by wind and solar⁵.

Coal tells the sharpest story. A fuel that supplied nearly a fifth of electricity in 2012⁸ supplied 5.9% in the year to March 2025¹, and most of that reflects the final coal plants running before closure. Nuclear has moved less dramatically but steadily downwards in share: 27.5% in 2012⁸, 27% in 2019⁹, 14.2% of UK electricity in 2023¹⁰ and 13% in 2024², as older stations have retired faster than new ones have been built.

The UK's generating fleet has also changed shape. In 2013 the UK had around 80GW of electricity generating capacity⁸, a figure that has since been reshaped by large additions of wind and solar, whose output per gigawatt is lower than a gas or nuclear plant's because they do not run all the time.

Hourly and seasonal forces behind the mix

The annual figures are an average, and in any single hour the mix can look completely different. Three things drive it: the weather, the time of day, and the level of demand.

Gas has been the dominant fuel used for electricity generation since 2008³, and it remains the flexible backbone. In the three months from September to November 2025, fossil fuels accounted for 33.4% of electricity generation by Major Power Producers, with gas at 33.3%¹¹. Nuclear, by contrast, runs close to flat: in the three months to May 2026 it was at 16.6% of Major Power Producers' generation, up 0.2% on the same period a year earlier¹².

Solar is the most strongly patterned source. In the first half of 2025, solar power rose by a third to a record 9.91 TWh, breaking generation records for five months in a row since March 2025¹³. On 8 July 2025 the grid saw the highest ever level of solar power at 14 GW¹³. Records have continued to fall: solar output reached a maximum of 15,427MW on 12 July 2026, according to NESO, and the record for power generated from embedded solar, the panels on roofs that never register on the transmission system, stands at 16.3 gigawatts, set at 12.30pm on 23 April 2026¹⁴. Solar's record daily share of generation is 19.5%, set on 24 May 2026¹⁴.

What keeps the system workable is that wind and solar rarely fail together. Analysis covering January 2017 to June 2025 found that just 2% of days in a typical year have both low wind generation and low solar generation¹³. Even so, the first half of 2025 saw the solar share of total generation increase by 2.4 TWh while combined wind and solar output fell by only 0.4 TWh, showing how one renewable's gain can offset another's dip within the same period¹³.

Research by the Royal Society suggests that the optimal solar-to-wind mix for a system like Britain's is 20/80¹⁰. That reflects Britain's weather: solar is abundant in summer but absent on winter evenings when demand peaks, while wind blows more strongly in winter. The practical consequence for a household is that the cleanest electricity hours are windy nights and sunny summer middays, and the most gas-dependent hours are still, dark winter evenings.

Construction pipelines: wind, solar and nuclear

The mix will keep moving because a large volume of new capacity is contracted or planned.

Offshore wind. Government ambition is up to 50GW of offshore wind by 2030, including up to 5GW of floating offshore wind¹⁵. The Climate Change Committee has called for growing from the promised 40GW in 2030 to 100GW or more by 2050¹⁶. The latest renewables auction in early 2026 secured 8.4GW of offshore wind overall¹⁷. Offshore wind forms the backbone of the future system, in the words of one official assessment¹⁸.

Solar. The solar PV sector in Great Britain could support up to 47 GW of installed capacity by 2030, according to official job-estimates methodology, and up to 35,000 direct and indirect jobs¹⁹. The Seventh Carbon Budget pathway has solar capacity increasing to 82 GW by 2040²⁰. Small-scale solar already matters: there was 18 GW of solar in the UK in 2024¹⁰, and plug-in solar panels became legal across Great Britain in August 2026²¹. Great British Energy plans to enable around 200 schools and up to 200 hospitals in England to install rooftop solar power²².

Nuclear. Nuclear's near-term trajectory is flat rather than growing: 41TWh, or 13% of generation, in 2024², and 16.6% of Major Power Producers' generation in the three months to May 2026¹². New stations are planned but the pipeline is slow, so nuclear's share of the mix is more likely to hold or slip than rise sharply this decade.

Differences across the four UK nations

The UK grid is not one uniform system, and the generation mix differs sharply between the nations.

Scotland generates a far larger renewable share than the UK average. In 2019, when the UK as a whole generated 29.3% of its electricity from renewables, the rest of the UK excluding Scotland managed 25.6%²³. Scotland's wind and hydro resources, and its early adoption of renewable targets, put it well ahead of that average, which is why energy supply in Scotland is a distinct subject from the GB-wide picture.

Northern Ireland is separate in structure as well as in mix: it shares a single electricity market with the Republic of Ireland, so its generation and prices are tied to that market rather than to the GB system. The detail is covered in energy supply in Northern Ireland. Wales sits inside the GB market but has its own generation profile and its own policy targets, covered in energy supply in Wales.

There is also an international comparison worth knowing. EU members produce on average almost 50% more electricity than the UK on a per capita basis²⁴. That gap reflects both the UK's falling total generation, from 319.7 TWh to 285 TWh in two years⁵, and the country's relatively efficient use of electricity. It also means the UK has less domestic headroom than its neighbours, which matters when demand rises again with electric vehicles and heat pumps.

Regulations governing reporting and building

Several rules and schemes determine which numbers are published and which technologies get built.

Fuel mix disclosure. Suppliers must publish the mix of electricity they supply, which is why the April-to-March year figures exist at all⁴. A supplier's disclosed mix can differ from the physical grid mix because of the way renewable guarantees are traded, which is one reason the published percentages vary between bodies.

Support schemes. The Smart Export Guarantee supports solar photovoltaics, wind, micro-combined heat and power, hydropower and anaerobic digestion, up to 5 megawatts in capacity, or up to 50 kW for micro-CHP, and installations must be located in Great Britain²⁵. Older rules reached further: under the Feed-in Tariff scheme, qualifying renewable electricity could be generated in a Member State of the EU and still supplied in GB²⁶. These schemes are what turned small-scale solar from a niche into 18 GW of capacity¹⁰.

Levies and price signals. Most of the regulated social and environmental levies are made on electricity rather than gas, increasing electricity's relative price, and a rebalancing through action of the UK Government and Ofgem has been described as urgently needed by the Heat Pump Sector Deal Expert Advisory Group²⁷. Because levies sit on electricity, the fuel that powers a home is made artificially expensive relative to gas for heating, which affects the choices households make.

Planning and finance. The Green Deal allowed microgeneration technologies subject to meeting the "golden rule": that estimated savings on bills should always equal or exceed the cost of the work²⁸. Contracts for difference and capacity payments, covered in contracts for difference and the capacity market, are the main instruments now deciding what gets built.

The mix and energy self sufficiency at home

The generation mix is the clearest single measure of how dependent UK households are on imported fuel, and the honest answer is that the dependence has reduced but not gone away.

The UK is, in the government's own words, "a net energy importer with a high dependence on gas and oil"²⁹. Around 26% of UK gas demand is for electricity generation⁶, so every still, dark evening when gas plants run, some of the electricity reaching homes is generated from imported fuel. That is the mechanism by which global gas prices reach a household electricity bill, and it is why the gas share of the mix matters to households even those that have never burned gas at home. The chain is explained in where Britain's gas comes from and how global events move UK energy prices.

The independence picture is genuinely mixed. On the supply side, 42.1% renewables⁴ and 16.2% nuclear¹ mean well over half of the annual mix comes from fuels that are not imported, and renewables now out-generate fossil fuels by 57%². Wind and sunshine are not traded on world markets, and their costs are largely fixed at auction. On the other side of the ledger, the 33.3% gas share⁴ is exposed to import prices, and the whole system remains dependent on the transmission and distribution networks, the system operator and a supplier, as energy security and household independence sets out.

For a household weighing its own options, the mix carries two practical messages. First, electricity is getting cleaner on average, and the cleanest hours are predictable: windy periods and sunny middays. Second, the gas share means grid electricity is not yet fully decoupled from imported fuel, so a home aiming for full independence still needs to think about when it draws power, not only how much. Household generation and demand flexibility are the levers a home actually controls, and the wider supply picture is covered in UK energy supply.