This is an extract from a recent research briefing “Planning for solar farms” prepared by the United Kingdom House of Commons Library.

In the Climate Change Act 2008, the UK Government set a legally binding target to reduce its greenhouse gas emissions by 80% by 2050, compared with 1990 levels. In 2019, the UK Government raised the 80% target to a 100% target by 2050. The devolved administrations have also set legally binding targets to reduce their greenhouse gas emissions to net zero compared with 1990 levels: Wales and Northern Ireland for 2050, and Scotland for 2045. In its Energy White Paper (December 2020) and Net Zero Strategy (October 2021), the government has set the aim of “a fully decarbonised, reliable and low-cost power system by 2035”. To meet its sixth carbon budget (a 78% reduction in emissions compared to 1990 levels by 2035), the government’s advisory Climate Change Committee estimated that solar power would need to provide 60 TWh of energy by 2035. It also estimated that an additional 3 GW of solar power would need to be installed per year to reach that level. One of the government’s aims is to “ramp up” the deployment of rooftop and ground-mounted solar systems to achieve a fivefold increase in solar power by 2035.

Trends in solar power capacity in the UK

As shown in the chart below, the cumulative installed capacity of solar power in the UK has grown substantially since 2010. In March 2024, there were around 1.5 million solar systems with a cumulative capacity of 15.8 GW in the UK (up from 22 megawatts (MW) or 0.02 GW, in January 2010). This includes solar systems of any size, both small-scale solar systems that are installed by households for their direct consumption and large-scale solar farms. It also includes both rooftop and ground-mounted solar installations. The growth in cumulative installed capacity of solar power in the UK has been much slower since 2017 compared to previous years. The rise prior to 2017 was mainly driven by subsidies provided through the Feed-in-Tariff scheme and the Renewable Obligation scheme.

•Total electricity generated from solar power: In 2022, electricity generation from solar photovoltaics (PV) amounted to 13.3 TWh. This was around 10% of renewable electricity generated and 4% of total electricity generated in the UK. Electricity is only part of the UK’s energy supply mix alongside oil and gas (among others).

•Location of solar farms in the UK: Most large-scale solar systems (that have a capacity of at least 1 MW) in the UK are ground-mounted. Only 5.5% (67 solar systems with a capacity of at least 1 MW) are installed on rooftops. These figures do not include small-scale solar systems that are installed by households or businesses. Of the ground-mounted solar farms that are either operational or have been granted planning permission and are under/awaiting construction, 28% are located in the South West of England and 15% in the South East of England. This is followed by the East of England, where around 13% of solar farms are sited, and the East Midlands, also 13%. 9% are located in Wales. There are fewer solar farms in the northern regions of England and in Scotland and Northern Ireland, where weather patterns are less suited to solar power.

•Public support for solar farms in the UK: The majority of respondents (88%) surveyed by the Department for Energy Security and Net Zero in spring 2023 expressed general support for the use of solar power in the UK. However, only around half (54%) of those surveyed said they would be happy about a solar farm in their local area. The results of the survey in the different parts of the UK are shown in the chart below. Therefore, broad trends in public attitudes towards solar power do not always reflect community-level support for solar farms. In evidence submitted to the Environmental Audit Committee, developers highlighted that a lack of public acceptance can sometimes pose a barrier to developments. The government also notes that local opposition to proposed solar farms can lead to delays in planning decisions and legal challenges. This can increase the cost of projects and, in some cases, result in projects being abandoned. 

Planning policy for solar farms in England: Installing solar farms usually requires planning consent. Depending on their size, solar farms will either require consent from the local planning authority (LPA) or from the Secretary of State for Energy Security and Net Zero. Solar farms with a generating capacity below 50 MW need planning permission from the LPA. Solar farms with a generating capacity above 50 MW are considered ‘nationally significant infrastructure projects’ (NSIPs) and require development consent from the Secretary of State.

Small-scale solar farms 

LPAs are responsible for determining planning applications for solar farms with a generating capacity under 50 MW. They will decide applications in line with their local plan unless ‘material considerations’ indicate otherwise. One important material consideration is the government’s National Planning Policy Framework (NPPF). It also provides a framework that can guide LPAs in drawing up their local plans. The NPPF states that the planning system should promote renewable energy and associated infrastructure. When deciding planning applications, the NPPF advises LPAs to give planning permission to renewable energy projects whose impacts are acceptable. It states that LPAs should “not require applicants to demonstrate the overall need for renewable and low carbon energy”

•Planning considerations: The NPPF advises LPAs to identify “suitable areas” for renewable energy projects. Supplementary planning guidance on renewable and low-carbon energy states that “there are no hard and fast rules” on how LPAs should identify suitable areas, however, it states that they should take into account the potential impacts of solar farms on the local environment. Supplementary planning guidance on renewable and low-carbon energy sets out what LPAs should consider when assessing planning applications for solar farms and drawing up their local plans.

•Siting of small-scale solar farms on agricultural land: The government advises LPAs that, for the “effective use of land”, large-scale solar farms should be located on previously developed (brownfield) land and non-agricultural land which is not of “high environmental value”. The NPPF guides development, including renewable energy developments such as solar farms, away from the ‘best and most versatile’ (BMV) agricultural land. The term BMW land is based on Natural England’s agricultural land classification scheme which grades agricultural land. BMV land is good to excellent quality land in grades 1, 2, and 3a. Where a developer can show that the use of agricultural land is necessary, the NPPF and planning guidance advise that poorer-quality land should be used instead of higher-quality land. LPAs should also consider whether a proposed project allows for continued agricultural use and/or encourages biodiversity improvements.

•Siting of small-scale solar farms on green belt land: It is the responsibility of LPAs to define and maintain green belt land in their areas. The NPPF makes clear that renewable energy projects, including solar farms, are not “appropriate” development for green belt land except in “very special circumstances”. The government states that it is up to LPAs to assess whether “very special circumstances” existed based on the merits of each case. It states that LPAs should “give relevant circumstances their due weight”

Large-scale solar farms

Under the Planning Act 2008, as amended by the Localism Act 2011, major energy projects are considered ‘nationally significant infrastructure projects’ (NSIPs). They require ‘development consent’ from the Secretary of State for Energy Security and Net Zero. Solar farms with a generating capacity over 50 MW are considered NSIPs. Applications for NSIPs are made to the National Infrastructure Directorate at the Planning Inspectorate. It will carry out an examination of the project and provide a report to the Secretary of State to help inform their decision. The final decision whether to grant, or refuse, development consent rests with the Secretary of State. If development consent is given, there is no need to obtain other consents, such as planning permission.

•Critical national priority for low-carbon infrastructure: The National Infrastructure Directorate will examine, and the Secretary of State will decide, NSIPs in line with the national policy statements (NPSs). These are statutory documents that are subject to public consultation and parliamentary scrutiny. The updated NPSs guide decision-making only for applications for NSIPs that were accepted for examination after the date (17 January 2024) when the government designated the updated NPSs. The updated NPS for energy EN-1 introduces a policy presumption for low carbon infrastructure known as “critical national priority” status. It states that there is an “urgent need” for low-carbon infrastructure, such as solar power, to ensure “a secure, reliable, and affordable supply of energy” and decarbonise the UK’s power supply in line with net zero goals. The updated NPS EN-3 also highlights the “important role” of solar power in “delivering the government’s goals for greater energy independence”

•Siting of large-scale solar farms on green belt land and in protected areas: Further, the NPS EN-1 also states that the Secretary of State should assume that low-carbon infrastructure meets tests that require “clear outweighing of harm, exceptionality, or very special circumstances”. They should assume, for example, that the urgent need for low-carbon infrastructure meets the “very special circumstances” test for development on green belt land as well as the “exceptional circumstances” test for development in protected areas, such as National Parks and National Landscapes.

•Siting of large-scale solar farms on agricultural land: The updated NPS EN-3 states that, although the suitability of a site should not be mainly determined by land type, solar farms should be sited on previously developed and non-agricultural land “where possible”. The NPS EN-3 notes, however, that it is “likely” that some agricultural land will need to be used for solar farms “at this scale”. The updated NPS EN-3 recommends that developers should try using poorer-quality instead of higher-quality agricultural land and avoid the use of BMV land “where possible”. However, the NPS EN-3 does not prohibit the siting of solar farms on agricultural land, including on BMV land.

Impacts on the environment, protected habitats and biodiversity

Environmental impact assessment: To be granted planning consent, certain developments have to undergo an environmental impact assessment process. It intends to ensure that the environmental impacts of a proposed development are assessed and can be considered by decision-makers (the LPA or the Secretary of State). Which projects require an environmental impact assessment is set out in the regulations: solar farms might require an assessment depending on their size, location and potential impact.

Habitats regulation assessment: Where solar farms might have a significant effect on habitats and/or species protected by the Conservation of Habitats and Species Regulations 2017, an LPA must undertake a habitat regulations assessment (HRA). Areas that are protected under the Habitats Regulations are: 

• special areas of conservation (SAC), which protect certain habitats and species (other than birds). 

• special areas of protection (SPA), which are protected areas for birds.

Biodiversity net gain: Under the Environment Act 2021, small-scale solar farms that are granted planning permission under the Town and Country Planning Act 1990 will be required to demonstrate at least 10% biodiversity net gain from 12 February 2024. From 12 February 2024, developers must assess the value of the natural habitat on the site before and after development, using Natural England’s biodiversity metric. They will be required to deliver 10% biodiversity net gain either onsite or offsite.

Planning application statistics

Applications for small-scale solar farms: The chart below shows how many planning applications for solar farms with a capacity of at least 1 MW were submitted to LPAs between 2010 and 2023. The number of applications increased every year between 2010 and 2015. It then decreased substantially in 2016 and 2017, following a reduction in subsidies. Since 2017, the number of applications has increased again. However, the capacity of solar farms that have been submitted for planning permission to LPAs has increased substantially over time, from an average of 4 MW in 2010 to 26 MW in 2023.

Applications for large-scale solar farms: The majority of applications for solar farms fell below the 50 MW threshold and were therefore submitted to, and usually decided by, LPAs. Until 2018, no applications for solar farms with a capacity above the 50 MW threshold were submitted to the Secretary of State for development consents. Since 2018, 13 NSIP applications for solar farms have been submitted.

Planning policy for solar farms in the devolved administrations

Wales: In Wales, solar farms will either require planning permission from the local planning authority (LPA), planning permission from Welsh ministers, or development consent from the UK Secretary of State for Energy Security and Net Zero, depending on their size. Solar farms with a generating capacity below 10 MW require planning permission from the LPA. Solar systems below 50 kW are covered by permitted development rights and do not need planning permission. Under the Planning (Wales) Act 2015, solar farms between 10 MW and 350 MW are classed as ‘developments of national significance’ (DNSs). They need planning permission from Welsh ministers. Solar farms with a generating capacity above 350 MW are considered ‘nationally significant infrastructure projects’ (NSIPs) and require development consent from the UK Secretary of State for Energy Security and Net Zero under Section 15 of the Planning Act 2008. Applications for DNSs are decided by Welsh ministers using the same policies that LPAs use on other planning applications. 

Scotland: In Scotland, unlike in Wales, the UK Government is not involved in decision making on planning applications for solar farms regardless of their size. Solar farms with a generating capacity above 50 MW require energy consent from Scottish ministers under section 36 of the Electricity Act 1989. They are also classed as ‘national developments’. All other applications for solar farms are made to, and decided by, the relevant planning authority. In Scotland, there is a distinction between ‘local’ and ‘major’ developments. In deciding applications for solar farms, planning authorities are guided by the Scottish Government’s National Planning Framework 4. The NPF4 also sets out which other factors planning authorities should consider when deciding planning applications for renewable energy projects.

Northern Ireland: In Northern Ireland, as in Scotland, there is a hierarchy of developments depending on their size: ‘regionally significant’, ‘major’ and ‘local’. Solar farms with a generating capacity above 30 MW may be considered ‘regionally significant’ developments. Whether a solar farm of that size is regionally significant is decided by the Department for Infrastructure. All other applications for solar farms with a generating capacity below 30 MW are made to, and would usually be determined by, the LPA. Solar farms with a generating capacity between 5 MW and 30 MW are ‘major’ developments. Solar farms with a capacity below 5 MW are ‘local’ developments.

Barriers to the expansion of solar power 

•Lack of grid capacity and difficulty securing grid connections: One of the major barriers to the expansion of solar power are difficulties in securing grid connections (in part because of a lack of grid capacity). To supply power to consumers, energy generators need to be connected to either the transmission or the distribution network. This requires approval from the DNOs, National Grid or both. Renewable energy companies highlighted difficulties connecting to both the transmission and distribution network and that DNOs and National Grid were unable to provide the connections required.

•Committee report and government response: In its inquiry into onshore solar energy, the Environmental Audit Committee found three main issues that had emerged. A lack of physical infrastructure, such as cables, transformers and substations, to distribute electricity. The queuing system. To be connected to the grid, generators need to make an application to National Grid or the DNO. Developers can make applications for projects that have not yet secured planning permission, which may “clog” the queue with projects that will not be completed. A lack of available data on solar installations, which can make it difficult to plan for and invest in grid infrastructure in the right location.

Access the complete report here