Resource Highlights:
Devon’s irradiance advantage applies just as much to farm buildings as it does to homes, with Exeter receiving 13% more solar radiation per year than the UK average.
Agricultural barn roofs are often ideal for solar: large, uninterrupted, south-facing surfaces that carry no dormer windows or roof lights to work around.
Rooftop installations on most agricultural buildings qualify as permitted development, meaning no planning application is required.
Tax relief: The Annual Investment Allowance allows most farm businesses to deduct the full cost of a solar installation from taxable profits in the year of purchase, up to the £1 million annual limit.
The practical guide to agricultural solar in Devon
Devon’s farming and rural business community operates against a backdrop of rising energy costs and significant on-site electricity demand, from milking equipment and refrigeration to irrigation pumps, heating systems and EV charging for farm vehicles. Solar panels address these costs directly, and the large roof areas available on agricultural buildings mean that farm-scale systems are typically far bigger than domestic installations, with correspondingly larger returns.
This page covers what agricultural solar involves, what makes Devon farms particularly suitable, what the planning and connection process looks like, and what you can expect from the economics of a farm solar installation.
Why Devon farms are well suited to solar
Devon has a higher-than-average proportion of land and buildings suited to agricultural solar, for several reasons:
South-facing roof planes: Many Devon agricultural buildings such as, barns, Dutch barns, grain stores and machinery sheds, are oriented to receive good solar exposure. South or south-west facing roof planes with minimal shading are ideal.
Scale: Agricultural buildings offer roof areas that domestic properties simply do not. A single barn roof may accommodate 50–100 kWp of solar panels, the equivalent of ten to twenty domestic installations.
On-site demand: Farms have continuous and often substantial electricity demand, particularly dairy farms (milking, cooling, heating), horticultural businesses (lighting, irrigation) and food production operations. High on-site consumption means more of the solar generation is used directly, improving the financial case.
Off-grid and part-grid properties: Many Devon farms have limited grid connections, agricultural land can be far from substations. Solar combined with battery storage can significantly reduce grid dependency and peak demand charges.
VAT zero-rating: Solar panel installations currently qualify for zero-rate VAT (until 31 March 2027, then 5% from 1 April 2027), applicable to the supply and installation of qualifying energy-saving materials.
Types of agricultural solar installation in Devon
Barn and outbuilding roof systems
The most common agricultural solar installation. Panels are mounted on an existing roof using a frame-mounted racking system. The roof structure is assessed to confirm it can carry the additional load, older or lighter-gauge roofing may require reinforcement. Systems range from 20 kWp on a small machinery shed to 200 kWp+ on a large Dutch barn.
Ground-mount systems
Where suitable roof area is limited or the building orientation is not ideal, ground-mounted solar arrays are an alternative for farms with available unshaded land. Ground-mount systems can be sized to any practical output and are often used where grid export is the primary income stream. Planning permission is almost always required for ground-mount systems.
Integrated roofing systems
For new agricultural buildings or when a roof needs replacing, integrated solar tiles or in-roof panel systems replace the roofing material itself rather than sitting on top of it. This is a higher-cost option but eliminates the cost of separate roofing materials.
Carport and canopy systems
Solar canopies over hard-standing areas, vehicle yards, feed stores, loading bays, generate electricity while providing covered space. Increasingly used on larger farms for EV charging infrastructure and protection of farm machinery.
Planning permission for agricultural solar
Agricultural solar installations do not always require planning permission, but the rules are specific and depend on system size, building type and location.
Permitted Development (no planning required) – conditions
The installation is on a building on agricultural land
The panels do not protrude more than 200mm from the roof surface
The highest part of the panels does not exceed the highest part of the roof
The total area of panels on the building does not exceed 1,000 m²
The installation is not on a listed building
The land is not within a National Park, Area of Outstanding Natural Beauty (AONB), or World Heritage Site, much of Dartmoor and parts of coastal Devon fall within protected designations, and these areas require planning permission
When planning permission IS required
Systems exceeding 1,000 m² panel area
Ground-mounted systems (any size)
Installations in National Parks, AONBs or other designated areas
Listed buildings (any system requires Listed Building Consent)
Any system where the structure or panels would be visible from a public highway in a sensitive landscape
We advise on planning requirements at survey stage and can assist with pre-application enquiries to the local planning authority where there is any uncertainty.
Grid connection for farm solar
Connecting a commercial-scale solar installation to the grid involves your Distribution Network Operator (DNO). In Devon, this is Western Power Distribution (now National Grid Electricity Distribution). The connection process varies depending on the size of the system:
Systems up to 3.68 kW (single phase) or 11.04 kW (three phase) can be connected without prior DNO approval for the grid connection itself, though MCS notification is still required
Systems above these thresholds require a formal DNO application, a connection offer (G99 application for systems over 16A per phase), and DNO approval before installation
Large farm systems, 50 kWp and above, typically require a protection relay, a metering solution for export measurement, and in some cases a new connection point from the DNO
The DNO application process can take 3 – 6 months for larger systems. We handle DNO applications on behalf of our clients and project-manage the connection alongside the installation.
Smart Export Guarantee for farm solar
Agricultural solar installations are eligible for the Smart Export Guarantee (SEG), which pays for electricity exported to the grid. SEG tariffs are set by the energy supplier rather than the government, and rates vary. The requirement is that the installation is carried out by an MCS-accredited installer, M&E Contrax holds current MCS accreditation for commercial solar PV.
For large farm systems with significant export volumes, some suppliers offer enhanced export rates or Power Purchase Agreements (PPAs), where a third-party purchases exported electricity at a contracted rate for a fixed period. We can introduce clients to PPA providers where this is appropriate.
Battery storage for farm solar
Agricultural solar can be combined with commercial battery storage to maximise self-consumption and reduce peak demand charges. Large-format lithium battery systems (typically 30 kWh to 200+ kWh for farm applications) store surplus generation during the day and release it during morning and evening demand peaks.
For dairy farms in particular, the milking periods (typically 5am–7am and 4pm–6pm) represent peak electricity demand at times when solar output is low or absent. Battery storage bridges this gap, drawing on generation from the main solar hours to cover these peaks without importing expensive grid electricity.
Talk to us about farm solar in Devon
M&E Contrax works with farms and rural businesses across Devon on solar PV installations from initial feasibility through to commissioning and DNO connection. Our installations are fully MCS-accredited, our engineers are experienced with agricultural roofing structures, and we handle planning, DNO applications and grid connection on your behalf.
If you would like to explore what solar could mean for your Devon farm or rural business, get in touch for a free feasibility discussion. We can advise on system size, likely return, planning requirements and the installation process without any obligation.
Frequently Asked Questions
Not always. Roof-mounted panels on agricultural buildings may qualify as permitted development if they meet specific conditions, including a maximum panel area of 1,000 m² and no protrusion beyond 200mm. Ground-mounted systems, installations in National Parks or AONBs, and systems on listed buildings require planning permission. We advise on planning at survey stage.
The practical limit depends on the roof area and structural capacity of the building, and on the available DNO connection capacity. Roof-mounted agricultural systems from 20 kWp to 250 kWp are common. Larger ground-mount systems have been installed on Devon farms, subject to planning and DNO approval.
Solar PV installations on agricultural buildings currently qualify for zero-rate VAT on the supply and installation of qualifying energy-saving materials. This applies until 31 March 2027, after which VAT will rise to 5% from 1 April 2027. Speak to your accountant about the specific VAT treatment for your business.
For systems requiring DNO approval, allow 3 – 6 months from survey to commissioning. The DNO application process is often the longest element. Once approval is confirmed, installation itself typically takes one to three days for a barn-scale system.
Yes. Solar combined with commercial EV charging infrastructure is an increasingly popular option for farms transitioning to electric vehicles, tractors, utility vehicles and van fleets. We can design systems that integrate solar, battery storage and EV charging under a single installation.
Reference links
Devon County Council: Solar PV landscape guidance for Devon
MCS: Find an MCS-certified installer
Energy Networks Association: Find your DNO by postcode
GOV.UK: Capital allowances: solar panels (HMRC internal manual CA22335)
GOV.UK: Planning practice guidance: renewable and low carbon energy
GOV.UK: Annual Investment Allowance
Guide published by M&E Contrax. Last reviewed October 2026. Information correct at time of publication. Planning rules, tax relief provisions, and DNO requirements are subject to change. Always seek independent advice from a qualified accountant and confirm planning requirements with your local planning authority before proceeding.
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