Energy Supply in Wales: Generation, Networks and Welsh Policy

Wales generates more electricity than it consumes, but most of that power still comes from fossil fuels. In 2023, Wales generated 23.2 TWh of electricity while consuming about 14.8 TWh, including losses¹. Renewables produced roughly 7.8 TWh of that generation, equivalent to 53% of Welsh electricity consumption¹. The rest came overwhelmingly from gas, which by 2023 represented 94% of Wales's fossil fuel based electricity generation¹.

The picture has been shifting. Total generation in Wales rose by nearly 20% in 2021 compared with 2020², then settled back as fossil output fell: electricity supply emissions in Wales dropped by 30% in 2023 compared with 2022³. Renewable generation, though, has grown slowly, by only 5% in the five years to 2023¹. The Welsh Government's stated vision is for Wales to generate 100% renewable energy that fully meets its needs by 2035⁴, which means a very large build out of wind, solar and other renewable projects over the next decade.

For a Welsh household, the practical questions are how much of the power in your sockets is renewable and Welsh, who owns the generation, and what say Wales has over its own energy system. The answers are mixed: Wales is a net exporter of electricity, renewable output already covers the equivalent of half of consumption, but the levers of energy policy, including the generation, transmission and supply of electricity and gas, remain largely reserved to the UK Government⁵.

Sources of Welsh power production

The most recent full picture comes from the Energy Generation in Wales 2023 report, written and produced by Regen for the Welsh Government and published in March 2025¹. It shows a system still anchored in gas. In 2023, Wales generated 23.2 TWh of electricity, of which approximately 7.8 TWh came from renewables¹. The total capacity of fossil fuel electricity generation in Wales stood at 4.3 GW, and natural gas represented 94% of Wales's fossil fuel based generation¹. Diesel generation, mostly small scale, accounted for 226 MW of capacity¹.

The 2021 edition of the same statistics gives the fuller breakdown behind those headline numbers:

Around 76% of renewable energy capacity in Wales generates renewable electricity, with the remainder producing heat².

Wind dominates the renewable mix. In 2021, 70% of all renewable electricity generation in Wales came from onshore and offshore wind². The geography of that capacity is uneven:

Renewable heat is a smaller but significant stream. Production of renewable heat in Wales was estimated at approximately 2.42 TWh in 2021, up slightly from 2.37 TWh the year before². That matters because energy consumption for heat in Wales, in homes, businesses and industry, is more than four times the consumption of electricity². Electricity represents only about 16% of Wales's estimated 92.8 TWh total energy consumption², so even a fully renewable power sector would leave most of the energy system, above all heat, still to decarbonise.

Factors behind the numbers

Two forces shape Welsh generation statistics: the behaviour of a small number of large gas plants, and the slow pace of renewable build out.

On the fossil side, the figures rest on a handful of big generators:

• Actual generation data for the 2023 report was collected from plants representing 95% of the major fossil fuel generating capacity in Wales¹.
• More than 70 smaller gas generators, with a combined capacity of 482 MW, operate principally as flexible peaking plants that run when the grid needs them².
• Small scale diesel generation represented 269 MW of fossil fuel capacity, with the largest single generator at 22.4 MW².

Because total generation is dominated by these plants, a change in how often they run moves the headline figures sharply, which is part of why generation jumped nearly 20% in 2021² and why electricity supply emissions then fell by 30% in 2023³.

On the renewable side, growth has been modest. Renewable electricity generation output in Wales increased by 5% in the five years to 2023¹; the 2021 report put the five year growth figure at 9%, compared with 140% in the preceding five year period². New capacity is arriving slowly: 116 MW of renewable electricity capacity was installed in 2021². The Welsh Government acknowledges the system is producing record amounts of green energy each year⁶, but the statistics show the record is being broken by small margins.

Demand is the third driver, and it points only one way:

• Demand for electricity is expected to double in Wales and the rest of the UK by 2050⁷, as new demands for clean electricity from transport, buildings and industry arrive⁸.
• Electric vehicles in Wales increased electricity demand by approximately 27 GWh annually by the end of 2021, while reducing petroleum demand by between 90 and 140 GWh⁹.
• The Welsh Government projects that electricity demand will continue to increase⁴.

That means the renewable build out has to outpace not just today's consumption but a much larger future load.

Wales against England, Scotland and Northern Ireland

Wales is a small part of the GB generation fleet. Under the Feed-in Tariff scheme, Wales accounted for 7.56% of installed capacity over the scheme's lifetime, against 77.80% in England and 12.25% in Scotland¹⁰. The same pattern appears in the older scheme year figures, which put Wales at 6.53% of installations and 7.56% of capacity¹¹.

Scotland generates a far larger renewable share. In 2019, Scotland's renewable electricity generation was compared with 29.3% for the UK as a whole, or 25.6% for the rest of the UK excluding Scotland¹². Wales in 2021 was at 28% of total generation from renewable sources², having reached 33% in 2020¹³. So Wales sits broadly in line with the UK average on renewable share, but well behind Scotland, and its renewable growth rate, 5% over five years to 2023¹, is the constraint.

On energy use, Wales has cut consumption faster than England. Total energy use in Wales fell by 16% between 2005 and the mid 2010s, 2% more than England over the same period⁹. Electricity use plateaued between 2016 and 2019 at around 14.8 TWh⁹, and stood at approximately 14 TWh, 16% of total energy consumption, in 2022¹⁴.

Looking forward, the Climate Change Committee's balanced pathway for Wales has variable renewables providing 78% of electricity generation by 2033, catering for increasing demand in Wales as well as the rest of Great Britain¹⁵. The Committee expects low-carbon generation in Wales to shift from 27% now to 100% by 2035, cutting Welsh power sector emissions⁸. Electricity supply emissions in Wales fell by 30% in 2023 compared with 2022³, a pace the CCC's UK-wide progress reporting treats as consistent with the direction needed, though Wales's continued reliance on gas means its power sector emissions remain sensitive to how often those plants are called on to run.

Energy policy and regulation in Wales

Wales does not control its own energy system. The split between the two governments is fixed:

• Reserved to the UK Government: the generation, transmission, distribution and supply of electricity, oil and gas, together with consumer protection, product standards, and weights and measures⁵.
• Devolved to Wales: heat and cooling networks, though not their regulation; schemes providing incentives to generate heat or cooling from non fossil, non nuclear sources; and the encouragement of energy efficiency otherwise than by prohibition or regulation⁵.

As the Welsh Government's own energy efficiency strategy put it, laws about energy efficiency are made by the UK Government, but Wales wants to do everything it can to use and manage its energy well¹⁷.

Within those limits, Wales uses the tools it has. The Climate Change (Wales) Regulations 2021 place obligations on a wide list of contributors, including all Welsh Government departments, UK Government departments, other public sector bodies, energy companies, transport providers, manufacturers, farmers and landowners, and individuals¹⁸. Net Zero Wales Policy 45 commits Wales to set higher energy efficiency standards for new builds through a review of Building Regulations Part L, the conservation of fuel and power requirements¹⁹. Building regulations influence emission reductions in both new and existing buildings in Wales¹⁹.

For households, the most direct rules are in building regulations and permitted development:

• Two sets of 2022 amendments changed how on-site electricity generation systems, such as rooftop solar, are regulated in Wales²⁰.
• They require that information about on-site generation systems be provided to the owner, and that confirmation be given to the local authority that such a system has been commissioned²⁰.
• Permitted development rights for solar installations in Wales apply where capacity does not exceed 50 kW for electricity generation and 45 kW for heat production²².
• Where a renewable electricity system such as a solar array or wind generator is replaced, the replacement should have an electrical output not less than that of the original system²³.

Planning rules also shape what gets built. Small scale energy from waste plants, under 10 MW, are only permitted in Wales if regionally necessary¹. The Welsh Government's wider ambition, set out in its renewable energy deep dive updates, is to scale up renewable generation in a way that maximises economic and social benefits for the people of Wales²⁶.

Community and locally owned power schemes

Ownership is where Welsh policy is most distinctive. The Welsh Government's vision is for Wales to generate renewable energy to at least fully meet its energy needs, and to use surplus generation to tackle the nature and climate emergencies²⁷. Alongside that sits a commitment to at least meet Wales's electricity needs from renewable energy sources²⁹.

The statistics show how far there is to go:

Locally owned generation is not exclusively renewable, with an estimated 100 MW of gas, diesel and coal capacity locally owned in 2021, in small scale projects such as farm diesel generators².

The Welsh Government backs this with money. It has announced £10 million of support for community led energy projects across Wales, tied to the goal of generating 100% of Wales's electricity from renewable sources by 2035³⁰. Earlier grants show the model in practice: Egni Solar Co-op received £45,000 of funding through the Welsh Government's Energy Service, including a £45,500 grant towards the development costs of its rooftop solar rollout³¹. These are small sums against the scale of the transition, but they signal where Welsh policy wants the ownership of generation to sit: with households, communities and local organisations rather than only with large developers.

For a household, the domestic slice of these figures is the part you can join. A rooftop solar installation adds to the 70,575 domestic renewable projects already recorded², benefits from permitted development rights up to the 50 kW threshold²², and must be commissioned and confirmed to the local authority under the 2022 regulations²⁰.

Implications for household energy self sufficiency

Wales's position is one of partial independence. The country generates more electricity than it consumes¹, and renewable output already equals about half of consumption¹, rising to 59% in 2022¹⁴ and 55% in 2021³². But the electricity arriving at a Welsh home is grid electricity, mixed from Welsh gas plants, Welsh wind and solar, and generation from across Great Britain flowing through the shared network. A household cannot choose to run on Welsh renewables alone; that choice is made by the market and the system operator, not the consumer.

The dependencies that remain are substantial:

• Gas for heating is reserved policy⁵, and heat consumes more than four times as much energy as electricity in Wales², so most Welsh homes remain tied to the gas network or other fossil heating, and to the wholesale prices that go with them.
• The electricity network itself, its charging, its connections and its operation, is governed by UK wide rules described on our page on the UK electricity generation mix and the wider picture of UK energy supply. Welsh households can find their own network operator through our guide to finding your gas and electricity network by postcode.

The targets, if met, change that picture. The Welsh Government's vision is 100% renewable energy fully meeting Wales's needs by 2035⁴, and the CCC's pathway has low-carbon generation in Wales reaching 100% by 2035⁸. Wales has a net zero target for 2050, set in March 2021 under the Environment (Wales) Act 2016¹⁹, and the Wales Net Zero 2035 Challenge Group, established in January 2023 under the Co-operation Agreement between the Welsh Government and Plaid Cymru and chaired by former Minister Jane Davidson, published its final reports in September 2024 examining pathways to net zero by 2035, ahead of the current 2050 target date³³. Its report will be considered as part of the plan for meeting Carbon Budget 3, covering 2026 to 2030³³.

What a household can control is the domestic slice: rooftop solar permitted up to 50 kW without planning permission²², efficiency improvements under the building regulations framework¹⁹, and, over time, the shift from gas heating that the doubling of electricity demand by 2050 implies⁷. The Welsh Government's own energy saving advice is blunt about the direction of travel: Wales's energy system is producing record amounts of green energy each year⁶, but with renewable generation up only 5% in five years¹, the 2035 vision depends on a build out far faster than anything in the recent record.