Solar Permitted Development Rights for Farms
Most farms over 5 hectares can install solar without full planning permission — but understanding Class A and Class R permitted development rights is essential before you start.
Solar Permitted Development for Farms: The Complete Picture
Agricultural solar installation in England is governed by two distinct types of permitted development rights in the Town and Country Planning (General Permitted Development) (England) Order 2015 (GPDO). Understanding which applies to your farm and the precise conditions attached is essential before committing to a solar project.
Class A of Part 6 (Agricultural and Forestry Development) covers rooftop solar on existing agricultural buildings. Class R (Agricultural Land) of Part 6 covers ground-mounted solar on agricultural land. Both require prior approval from the local planning authority — neither is fully automatic. The distinction matters because the conditions, limits and assessment criteria differ significantly between the two classes.
Class A: Rooftop Solar on Agricultural Buildings
Class A permits the installation of solar panels on existing agricultural buildings on agricultural units of 5 hectares or more, as a permitted development (not requiring full planning permission). The key conditions are:
| Condition | Class A Requirement |
|---|---|
| Agricultural unit size | 5 hectares or more |
| Building type | Must be existing, established agricultural building |
| Prior approval | Required from the LPA |
| National Parks/AONBs | Prior approval required with landscape assessment |
| Listed buildings | Not permitted — listed building consent required |
| Cumulative capacity | No explicit limit stated in Class A (but Class R 1MW limit applies to ground-mounted on same unit) |
| Panel projection | Must not project more than 0.2m above the plane of the roof surface |
Prior approval for Class A rooftop solar is typically straightforward on modern steel-clad agricultural buildings away from sensitive landscapes. The LPA assesses siting, design and appearance. For buildings in National Scenic Areas, AONBs, National Parks or World Heritage Sites, a more detailed landscape assessment may be required.
Class R: Ground-Mounted Solar on Agricultural Land
Class R is the more frequently used permitted development route for larger farm solar installations. It permits the installation of solar panels on agricultural land forming part of an agricultural unit of 5 hectares or more, subject to conditions and prior approval. Class R conditions:
| Condition | Class R Limit |
|---|---|
| Agricultural unit minimum size | 5 hectares |
| Maximum capacity per agricultural unit | 1 megawatt (cumulative, all Class R arrays) |
| Maximum area per individual array | 0.5 hectares (footprint) |
| Setback from unit perimeter | Not within 5 metres of boundary |
| Maximum height (ground-mounted) | 4 metres above ground level |
| Prior approval | Required from LPA |
| Maturation period | Cannot be installed within 5 years of agricultural unit being assembled (acquired) |
| Removal obligation | Must be removed and land restored if no longer used for energy generation |
The 1MW limit is cumulative across all Class R arrays on the same agricultural unit. A farm with multiple fields can install multiple arrays totalling up to 1MW without exceeding the limit. The 0.5 hectare per-array limit means very large installations may need to be split across multiple field locations (each no more than 0.5ha), each potentially requiring a separate prior approval.
Prior Approval: What It Involves
Documents Required
A prior approval application for Class R farm solar must include:
- Site location plan (1:2500 or 1:1250) showing the application site within the agricultural unit
- Site layout plan showing array dimensions, setbacks, access tracks and cable routes
- Photographs of the site from multiple viewpoints
- Method statement describing installation methodology, foundation type and cable routing
- Landscape and visual impact assessment (for sites in or near National Parks, AONBs, AGLV)
- Ecology survey or screening report (for sites with potential biodiversity value)
- Drainage impact assessment (if on Grade 1 or 2 agricultural land)
- Agricultural land classification report (if applicable)
The 56-Day Rule
The LPA must determine the prior approval application within 56 days of accepting a valid application. If the LPA fails to determine within 56 days, the development may proceed as if prior approval had been granted. This statutory clock is an important protection for farmers against LPAs that are slow to process applications.
In practice, most Class R prior approval applications are determined within 30–45 days. LPAs consult with statutory consultees (Historic England if heritage assets nearby, Natural England if protected landscapes), which can extend the timeline if site-specific issues are identified.
When Prior Approval Is Refused
Prior approval can be refused on grounds of: landscape and visual impact (especially in designated landscapes); impact on protected wildlife habitats; impact on scheduled monuments or heritage assets; or conflict with the specific conditions of Class R. Refusal of prior approval does not prevent a full planning application being submitted for the same scheme.
Farms Under 5 Hectares: Full Planning Permission Required
Agricultural units of less than 5 hectares cannot use Class A or Class R permitted development rights. All solar installations on holdings below the 5ha threshold require full planning permission from the local planning authority.
The planning policy context for small farm solar is generally supportive in England under the NPPF (National Planning Policy Framework), which states that planning should help support the transition to a low carbon future and approve renewable and low carbon energy development wherever the impacts are acceptable. Most applications for solar on small farm buildings or small ground-mounted arrays are approved, though the planning fee and the time involved are greater than for prior approval.
In Scotland, Wales and Northern Ireland, equivalent but separately-legislated PD rights apply. The Scottish PD order allows agricultural solar installations under broadly similar conditions but with different acreage thresholds and specific Highland planning requirements. Welsh PD rights are set out in the Town and Country Planning (General Permitted Development) Order 1995 (as amended).
Protected Areas and Heritage Sites: Extra Constraints
| Designation | Impact on Solar PD |
|---|---|
| National Park | Prior approval includes mandatory landscape assessment; arrays not permitted where significantly harmful to character |
| AONB (Area of Outstanding Natural Beauty) | Similar to National Park; LPA may apply stricter visual impact assessment |
| World Heritage Site | Prior approval; UNESCO buffer zone requirements may apply |
| Scheduled Monument | No permitted development near or on scheduled monuments — full planning required |
| Listed Building | No PD for solar on listed buildings — listed building consent (LBC) required for any alteration to structure |
| SSSI (Site of Special Scientific Interest) | May require Natural England consent if solar installation could affect SSSI notified features |
| Green Belt | PD rights apply but LPA may apply special scrutiny to openness impact |
The majority of UK farmland outside these designations qualifies straightforwardly for Class R prior approval. We carry out a desktop planning constraints check at the survey stage to identify any designations, TPO trees or heritage designations that could affect the PD route.
Combining PD and Full Planning for Larger Schemes
For farms wanting to install more than 1MW, the standard approach is to use the 1MW PD allocation for an initial installation and then apply for full planning permission for any additional capacity. Planning applications for farm solar over 1MW are determined under the broader NPPF renewable energy policy framework rather than the PD conditions — they have more flexibility in some respects but require more comprehensive assessment.
For very large projects (5MW+), the development is categorised as a Nationally Significant Infrastructure Project (NSIP) and determined by the Planning Inspectorate rather than the local planning authority, under the Infrastructure Planning Commission regime.
Case Studies: Prior Approval in Practice
Case Study: 750kW Class R on Two Separate Fields, Lincolnshire
An arable farmer installed two 375kW arrays on separate fields within the same agricultural unit. Each field array (0.375ha footprint) was below the 0.5ha per-array limit. Two prior approval applications submitted simultaneously to the district council. Both approved in 38 and 44 days respectively. No landscape conditions imposed (open farmland, no designated areas). Combined system commissioned 5 months after initial survey.
Case Study: Class R Prior Approval Refused, Oxfordshire AONB
A farm in the Chilterns AONB submitted a prior approval for a 400kW ground-mounted array. The LPA refused prior approval citing significant landscape and visual impact, particularly visibility from a nearby public right of way. The farmer submitted a revised scheme with enhanced hedgerow planting and visual screening. Second application approved in 52 days with landscaping conditions.
Case Study: Class A Rooftop on Complex Agricultural Building
A dairy farm in South Wales installed solar on a newly-refurbished milking parlour building. Class A prior approval applied for under GPDO. The building's main entrance faced a village lane, and the council required the panels to be non-reflective and minimally visible from the road. Panels sited on the rear-pitch and side elevations. Approved in 29 days.
What is Class R permitted development for solar?
Class R of the GPDO allows ground-mounted solar on agricultural land forming part of a 5ha+ agricultural unit without full planning permission. Maximum 1MW per agricultural unit, 0.5ha per array. Prior approval from the LPA is required.
Do I need planning permission for solar on my farm?
If your farm is 5 hectares or more, you can use Class A (roof) or Class R (ground) permitted development rights with prior approval. If under 5ha, or in a National Park, AONB or near a listed building, full planning permission is required.
How long does prior approval take?
The LPA has 56 days to determine a prior approval application. Most applications are decided within 30–45 days. If the LPA doesn't determine within 56 days, the development may proceed as approved by default.
What is the 1MW limit for farm solar?
Class R permits a maximum of 1MW of ground-mounted solar per agricultural unit (cumulative). Rooftop solar under Class A doesn't count toward this limit. For more than 1MW, full planning permission is required.
Can I install solar on a farm in a National Park?
Yes, but prior approval includes a mandatory landscape and visual impact assessment. The LPA will scrutinise the proposed design, screening and visual impact more carefully than for undesignated farmland. Approval is still routinely granted for well-designed schemes.
Get Farm Solar Planning Advice
Our planning specialists advise on Class A, Class R and full planning routes for farm solar. We prepare prior approval applications and manage LPA consultation as part of our project service.
Get a Free SurveyRecent Changes to Farm Solar Permitted Development Rights
The Town and Country Planning (General Permitted Development) (England) Amendment Order 2023 expanded Class R permitted development rights for agricultural solar, increasing the maximum installation size from 1MW to 5MW per agricultural unit (on units of 5 hectares or more). This change, which came into effect in May 2023, significantly extended the scope of farm solar that can proceed without full planning permission, subject to prior approval from the local planning authority.
The prior approval process under Class R requires assessment of: siting and design of the development; landscaping and screening; and the method of decommissioning and site restoration. Unlike full planning permission, prior approval does not allow the planning authority to refuse on general policy grounds — it can only refuse if the specific prior approval criteria (siting, design, landscape, restoration) are not met. This makes Class R a considerably faster and more certain route than full planning permission for qualifying farm solar installations.
Can I install ground-mounted solar on rented farmland?
Yes — Class R permitted development rights apply to the agricultural unit (the land), not the landowning entity. Tenant farmers can apply for prior approval for ground-mounted solar on rented agricultural units of 5 hectares or more. However, the lease agreement must be checked carefully — some agricultural leases require landlord consent for structural changes to the land, and a solar installation is typically classified as a structural change. Landlord consent should be obtained before submitting a prior approval application.