Ground-Mounted vs Rooftop Solar for Farms

Farms are unusual in UK commercial solar because they almost always have two viable places to put panels: the large, simple roofs over barns, grain stores, parlours and livestock sheds, and the land itself. Most sectors only choose a funding route. A farm chooses a whole site type first, and that decision shapes the cost, the planning path, the grid application and the income model. This guide compares ground-mounted and rooftop solar panels for agriculture on the terms that actually decide it for a working farm.

The two options in plain terms

Rooftop solar. Panels go on existing farm buildings: machinery sheds, grain stores, dairy parlours, poultry and pig units, glasshouses. You use roof space you already own, so no land comes out of production and usually no planning application is needed: roof panels on farm buildings are permitted development with no capacity cap, though systems over 50 kW need prior approval from the council. The trade is that you are capped by the roof area and orientation you have, and older buildings may need work before they can carry panels.

Ground-mounted solar. Panels sit on frames in a field, typically on marginal or underused land. You can build far larger than any single roof allows, angle every panel optimally, and on the right land run sheep underneath or, subject to scheme rules, keep environmental actions running alongside. The trade is that a ground-mount array should be treated as needing full planning permission and takes land out of cropping.

The two are not mutually exclusive. On many holdings the right answer is rooftop on the buildings plus a ground-mount lease on the poor pasture, so ask the installer to model both together rather than treating them as rivals.

The two routes head to head

The trade-offs line up fairly cleanly across the two site types:

The headline trade is scale and siting freedom versus simplicity and self-consumption. Ground-mount gives you almost unlimited size, optimal panel angle and a lower cost per kilowatt at scale, but it costs you land, a planning application and usually a bigger grid job. Rooftop gives you a fast, low-friction install that sits directly over your load and pays back quickly, but you take the roof you have and live within its limits.

When rooftop wins

Rooftop is the default for most farms, and for good reasons.

The first is self-consumption, the single biggest driver of return in farm solar. Every unit you use on site displaces a unit you would otherwise buy at full retail price, while every exported unit earns only the lower Smart Export Guarantee rate. Rooftop panels sit directly over the load, so an enterprise with steady daytime or round-the-clock demand keeps most of what it generates. A dairy is the clearest case: milk cooling, parlour pumps and lighting run 24/7, so an array sized to that daytime load uses most of its output on site and indicative payback lands around 4 to 7 years; sized to annual consumption it exports much more (an Irish Teagasc model of a 100-cow farm found 27% used on site). Poultry and pig units with high year-round ventilation loads behave similarly. For these holdings, rooftop is not just easier, it is the better economic answer.

The second is planning and speed. Rooftop PV on agricultural buildings is permitted development under GPDO Part 14 Class J, with no capacity cap since December 2023; systems over 50 kW need prior approval from the council on design and appearance, which is far lighter than a full planning application, removing months of timeline and a layer of cost and risk.

The third is land. If your ground is productive, taking it out of cropping rarely makes sense when idle steel roofs sit over the same business.

Rooftop wins when you have suitable buildings, a decent year-round load, and roofs in sound condition or worth re-roofing anyway.

When ground-mount wins

Ground-mount comes into its own in a narrower but important set of cases.

The clearest is underused marginal land. A field that crops poorly, a corner that floods, rough pasture that yields little, these are where ground-mount shines, because the opportunity cost is low and the array can be sized to suit. This is also the basis of the lease model: a developer leases the land, typically around £800 to £1,000 per acre per year (Arup survey for DESNZ, 2025; land agents quoted £850 to £1,100 in 2023-24) on a 25 to 40 year term, well above the arable rental poor ground would otherwise command. The developer carries all the capital and operational risk, and on suitable sites the land keeps grazing sheep.

The second is scale. If your electrical load or income ambition is larger than your roofs can serve, ground-mount is the only way to get there. Arable holdings with seasonal grain-drying peaks, or estates pursuing a multi-megawatt scheme, cannot fit that capacity on building roofs.

The third is roof constraints. Where farm buildings carry asbestos cement sheeting, or spans too weak to take panels, the rooftop route needs a strip-and-reclad first. Where that re-roof is not worth doing on its own merits, ground-mount sidesteps the roof question entirely.

Ground-mount wins when you have land you can spare, a need for more capacity than your roofs allow, or roofs that are not solar-ready.

Planning and land-use considerations for farms

This is where the two routes diverge most sharply. Rooftop PV on agricultural buildings is permitted development under the GPDO with no capacity cap, though systems over 50 kW need prior approval, and listed farm buildings fall outside permitted development and need consent. Beyond that, the planning path is light.

Ground-mount is a different matter. There is no reliable permitted development route for a commercial-scale farm array, so a ground-mount scheme should be treated as needing full planning permission. Larger schemes may also need Environmental Impact Assessment screening by the local planning authority. Planners weigh the loss of agricultural land, visual impact, and increasingly biodiversity, so the quality of the land matters: a scheme on genuinely marginal ground with a dual-use or grazing plan is far easier to consent than one on prime arable. Agrivoltaic designs, where panels sit above grazing or sheltering crops and the land stays in agricultural use, strengthen the planning case considerably and, subject to scheme rules, may sit alongside separate environmental actions on the same acres. You can read the scheme detail on the Sustainable Farming Incentive pages at GOV.UK.

Grid connection shapes both routes but bites harder on ground-mount. A G99 application to the DNO is required before installation for anything above 16 A per phase (3.68 kW single-phase, about 11 kW three-phase), which covers almost every farm system, and rural networks are frequently capacity-constrained. A large ground array needs a larger export connection that, on a congested network, can take many months to secure. Where export capacity is the bottleneck, a rooftop system sized for self-consumption only, with no export, can be commissioned far faster, one more reason rooftop tends to be the quicker win.

If you rent the land or buildings, any structural alteration or change of land use needs landlord consent on both routes. Most institutional rural landlords run standard tenant agreements, so this is friction to plan for rather than a barrier.

A worked example

To see how this plays out, take an illustrative case, an illustrative example, not a real project. Imagine a mixed family farm with a 180-cow dairy and around 12 acres of marginal pasture that crops poorly. The parlour and youngstock shed roofs carry roughly a 120 kW rooftop system of around 220 panels, generating about 108,000 kWh a year. Because milk cooling runs around the clock and the array is sized to that daytime load, assume around three-quarters of the output is used on site; at 26p avoided import and 4p export that gives a simple payback of roughly five years before tax relief, and full first-year relief under the AIA shortens it further. That system is permitted development, subject to prior approval because it is over 50 kW, sits over the load, and takes no land.

Ground-mount could not be justified on the productive fields, but the 12 acres of poor pasture is a different question. Rather than buy an array, the farm leases it to a UK developer for a roughly 1.8 MW scheme generating about 1.7 million kWh a year, on a 25-year lease at around £1,000 per acre per year (illustrative). The land keeps grazing sheep, and the developer carries all the capital and grid risk. The farm uses both site types for different jobs: rooftop for cheap self-consumed power on the buildings, a ground-mount lease for reliable income on land that earned little. The figures are illustrative and depend entirely on your roofs, your land, your load profile and the developer terms in your region.

How to choose

The decision tree is short. If you have suitable building roofs, a steady year-round load and sound or re-roofable buildings, start with rooftop, it pays back fastest, usually avoids a full planning application and takes no land. If you have underused marginal land, need more capacity than your roofs can hold, or your roofs are not solar-ready, consider ground-mount, owned or as a developer lease. On many farms the answer is both.

The right answer is specific to your buildings, your land and your load, so the sensible next step is to model both against your real meter data. Our cost guide sets out the underlying numbers, the grants and funding page covers the AIA, SEG and lease economics for each route, and the savings calculator gives an instant indicative figure. If you are still weighing whether solar suits your holding at all, our is solar worth it for farms guide works through the deciding factors. When you are ready, request a free quote and ask the installer to model rooftop against ground-mount for your farm.