Solar Panels for UK Farms — From Dairy Parlours to Ground-Mount

Government statistics give the most reliable benchmark. DESNZ’s solar PV cost data for April 2025 to March 2026, based on MCS-certified installations in Great Britain, puts the median cost of a 10–50 kW system at about £1,262 per kW and the mean for non-domestic 10–50 kW systems at about £1,259 per kW (including VAT where applicable, excluding batteries). At the median, a 30 kW farm roof system is roughly £37,900 and a 50 kW system roughly £63,100. The statistics stop at 50 kW, so for a larger farm array compare at least three itemised quotes. See our [pricing page](/agricultural-solar-panel-cost/) for more detail.

In England there is no open capital grant for farm solar at the time of writing. The Improving Farm Productivity grant, which paid 25% of eligible costs on rooftop and irrigation-reservoir solar (grants of £15,000 to £100,000), has closed its second round. Wales, Scotland and Northern Ireland run their own schemes with different rules and timetables, so check the relevant government site before planning around a grant. Tax relief is the dependable support: the £1m Annual Investment Allowance lets most farm businesses deduct the full cost of solar panels in the year of purchase. See [farm solar grants](/grants/) for the current position.

In England, solar panels on the roof of an existing agricultural or other non-domestic building are usually permitted development under Class J of Part 14 of the General Permitted Development Order. Panels on a pitched roof must not protrude more than 0.2 m beyond the roof slope, panels on a flat roof must not rise more than 1 m above its highest part, and no equipment may sit within 1 m of the roof edge. The old capacity cap was removed in December 2023, but arrays above 50 kW need prior approval from the council on design and external appearance. Listed buildings are outside Class J, and ground-mounted farm arrays generally need full planning permission. Wales, Scotland and Northern Ireland have their own rules. See the [Class J rules for farm buildings](/solar-panels-for-agricultural-buildings/) for the detail.

Allow roughly 12–24 weeks from first enquiry to commissioning. The desk feasibility and site survey come first, then the fixed-price proposal. The longest step is usually the grid: most farm arrays need a G99 application to the network operator, and in England an array above 50 kW also needs Class J prior approval from the council. Installation itself takes from a few days to several weeks depending on size. A good installer plans the work around milking, harvest and lambing.

Yes. There are three viable routes: tenant-installs with landlord consent (cleanest for FBTs over 10 years), landlord-installs with tenant offtake (typical of institutional estates), or a tripartite PPA with no capital from either party (best for shorter FBTs). Whichever fits, open the conversation with your landlord early.

It depends on three numbers: what the system costs, how much of its output the farm uses itself, and what you pay for grid electricity. DESNZ data puts a typical 10–50 kW installation at about £1,262 per kW, and PVGIS gives roughly 870–1,045 kWh per kWp a year on south-facing 10–30° farm roofs between York and Exeter. Every kWh used on the farm saves the full import price, while exported power earns a lower Smart Export Guarantee rate, so high daytime users such as dairy, poultry and pig units recover the cost fastest. With England’s Improving Farm Productivity grant closed, ask for a payback calculation built from your own half-hourly meter data rather than a headline figure.

It shouldn’t. Ask the installer to schedule around your calendar: dairy work between milkings with short, planned electrical isolations; arable work outside harvest and drilling; poultry work outside placement and depopulation weeks; and lambing sheds outside lambing. Agree the programme and any isolation times in writing before the contract is signed.

Often, if the farm uses power in daylight. Size matters more than acreage: DESNZ data shows 10–50 kW systems cost roughly 30% less per kW than the smallest (0–4 kW) systems (median £1,262 against £1,780 per kW in 2025/26), so a small farm with a steady daytime load, such as milk cooling or a farm shop, can still make the numbers work. Size the system to your half-hourly meter data rather than the roof area, and consider a battery if much of your use falls in the evening.

EU PVGIS data (SARAH3, 14% system losses) gives a south-facing 30° roof about 1,045 kWh per kWp a year near Exeter, 1,026 near Peterborough, 963 near Shrewsbury, 960 near York and 877 near Aberdeen. A shallow 10° barn roof makes about 8–10% less: 957 near Exeter and 868 near York. So a 50 kWp array on a 30° roof near York would generate roughly 48,000 kWh a year, most of it between April and September. See [how much a farm roof generates month by month](/blog/can-solar-panels-power-a-whole-farm/).

Solar panels are special rate expenditure under section 104A(1)(g) of the Capital Allowances Act 2001. Most farm businesses can use the £1m Annual Investment Allowance to deduct the full cost in the year of purchase. Companies can instead claim the 50% first-year allowance on new and unused special rate assets bought from 1 April 2023, with the rest going into the special rate pool at 6% a year. Full expensing covers main rate assets only, so it does not apply to solar panels. Take advice from your accountant on your own position.