How much do renewables contribute to the UK’s energy mix and what policies support their expansion?
Renewable energy comes from sources that are not depleted when used but are replenished naturally. In the UK the main renewable energy sources used are wind power, plant biomass and solar power.
Sources and contribution of renewable electricity generation
Since 2000, when renewables accounted for just 2.8% of all electricity generated in the UK, their contribution has grown substantially. In 2022, 40% – a record amount – of electricity came from renewables. This represented an increase of 5% from 2021, mostly due to additional wind generation (due to high wind speeds and more offshore capacity). Wind was the second largest source of electricity (26.8%) in 2022 after gas. The summer heatwave of 2022 meant that solar power also increased its contribution, to 4.4%. Biomass accounted for 5.2%, and hydro 1.8%.
Generation from solar photovoltaics has benefited from government subsidies and the declining cost of panels over the last decade, with capacity increasing from 95 MW in 2010 to 13,800 MW at the end of 2021. Electricity generation from wind power in the UK increased by 715% between 2009 and 2020, producing 75,610 gigawatt hours (GWh) in 2020. Most of this is from offshore wind farms with some contribution from onshore, though the latter has suffered from a lack of government support through the planning system in recent years.
Biomass makes an important contribution to the renewables mix by percentage but is controversial for the carbon emissions derived from importing wood pellets (most used in the UK come from overseas) and the combustion process used to produce power which does not capture emissions. Bioenergy with carbon capture and storage (BECCS) is a way to reduce the carbon footprint of these power stations, as is being trialled by Drax in North Yorkshire, for example.
Small contributions come from hydropower and tidal power. Most of the UK’s hydroelectricity is generated by ‘large-scale’ schemes (producing more than 5 MW) in the Scottish Highlands. There is limited additional scope for hydropower because most of the most suitable sites in both economic and environmental terms are already in use. It is estimated the UK has around 50% of Europe’s tidal energy resource, but the tidal stream industry is in its early stages. However, the costs of deploying turbines in tidal streams are falling and more tidal projects are likely to be commercialised in the UK in the coming years.
Battery storage is important to support renewable electricity generation. These devices enable energy from renewables to be stored and then released when customers need power most. There is a growing pipeline of energy storage projects in the UK, many of them co-located with solar farms.
Renewables in heat generation and transport fuel
The proportion of heat from renewable sources, such as heat pumps, has steadily increased in the UK, from 1.8% in 2007 to 7.3% in 2021. The Government aims to phase out the installation of new and replacement natural gas boilers by 2035, which will necessitate making low-carbon heat alternatives cheaper. The predominant options are heat pumps, district heating and hydrogen boilers. However, analysis suggests hydrogen heating is significantly more expensive compared with other clean heating technologies. Geothermal power – heat from underground – is not widely harnessed in the UK but construction of the first geothermal power plant is expected to start in 2023, at United Downs near Redruth in Cornwall, where the underlying granite is heat-producing.
In 2021 7% of total road and non-road mobile machinery fuel was ‘renewable fuel’, 12% of which was produced from UK-origin feedstocks (crops or wastes, e.g. food waste). Biodiesel and bioethanol, which are blended with diesel and petrol to be sold at filling stations and on the market, represent the main renewable fuels used in the UK.
The UK has also set targets for the use of hydrogen in transport, including for heavy-duty road vehicles. Currently, approximately 2% of England’s bus fleet is zero emission – either battery electric or hydrogen fuel cell.
What targets and policies are there for renewable energy in the UK?
The Government published its Net Zero Strategy in 2021, which sets out how it will meet the target legislated in 2019 of reaching net zero greenhouse gas emissions by 2050. The Strategy includes the ambition for the UK to be powered entirely by ‘clean electricity’ (which includes from nuclear power as well as renewables), subject to security of supply, by 2035.
On wind power, the Government’s British Energy Security Strategy of April 2022 includes an ambition for up to 50GW of offshore wind by 2030 (up from more than 10GW currently) – which is more than enough to power every home in the UK; and the intention to consult on limited further development of onshore wind. The Strategy states the Government will consult on amending planning rules in favour of more ground-mounted solar and will simplify the planning process for rooftop solar. It also commits to exploring tidal and geothermal opportunities and the possibility of international projects providing clean energy, by expanding the Contracts for Difference (CfD) scheme, for example. The CfD scheme incentivises investment in renewables by protecting developers from the volatility of wholesale electricity prices. The policy has been particularly successful at reducing the costs of offshore wind, which have fallen from £120/MWh in the first auction round (2014/15) to £37/MWh in the latest auction (as of 2022). However, increasing competition for grid connections is likely to slow down the deployment of new projects in the coming years.
Another key policy for the power sector has been the Renewables Obligation (RO) scheme, which operated between 2002 and 2017, and required licensed electricity suppliers to source a specified proportion of electricity from eligible renewable sources.
For small-scale generators of renewable electricity the Smart Export Guarantee (SEG) tariff pays for any power they export to the national grid. It applies to solar, onshore wind, anaerobic digestion and hydro installations of up to 5MW and micro-CHP (combined heat and power) that can produce electricity up to 50kW.
In the heating sector, the Boiler Upgrade Scheme (BUS) provides grants to eligible households in England and Wales to cover part of the cost of replacing a gas, oil or electric heating system with a heat pump or biomass boiler. In this area, the Government had a Domestic Renewable Heat Incentive (RHI), but this closed to new applicants in March 2022.
On transport, the Net Zero Strategy includes a commitment to end the sale of new petrol and diesel cars by 2030, and a commitment for all cars to be fully zero emissions capable by 2035. Meeting these targets requires more widespread charging infrastructure and support for battery production. There are government-backed plans for Nissan and Envision AESC to produce batteries in North East England, though another firm, Britishvolt, which was to build a ‘gigafactory’ in Blyth, Northumberland, with government support, went into administration in January 2023.
Decarbonisation of transport is also supported by the Renewable Transport Fuel Obligation (RTFO), under which suppliers of transport fuel – of at least 450,000 litres a year – must show that a certain percentage comes from renewable and sustainable sources.
The Government published its first Hydrogen Strategy in 2022, which sets out ambitions for increasing the use of low-carbon hydrogen (not all hydrogen is low-carbon) across different economic sectors, including delivering a 5GW production ambition by 2030.
This explainer was written by Georgina Kyriacou, with review by Josh Burke.