Arable Farms: Solar panels for dairy farms

Why arable ground attached to a dairy is a powerful place for solar

Many dairy farms are mixed holdings that also crop a good acreage, whether that is forage maize and wholecrop grown for the herd or combinable crops sold off the farm, and that arable side opens up solar options the dairy buildings alone cannot. You have large grain store and machinery shed roofs, you often have marginal corners that crop poorly, and you have a seasonal load that spikes hard at harvest when the grain dryer runs flat out. For a dairy business, that means solar can do two jobs at once: cut the round-the-clock cost of milking, and turn underused arable land or roof space into a fresh income stream. The right answer can be rooftop, ground-mount, or both together, and it depends entirely on your load profile and how much capital you want to commit. With the move from the Basic Payment Scheme to the Sustainable Farming Incentive reshaping farm income, the arable side of a dairy holding is one of the best places to build resilience and replace lost support payments with something durable.

Supermarket pressure runs through the milk contract and the grain contract alike. Tesco, Sainsbury's, M&S and Waitrose all push Scope 2 and Scope 3 expectations down to suppliers, and on-farm solar generation is auditable evidence that supports those returns through schemes such as CDP Supply Chain disclosures. For a dairy that also supplies grain or sells forage, solar strengthens the whole-farm sustainability story rather than just the parlour, and several growers have used that evidence as part of winning or retaining a retail contract.

It is also worth being honest about where arable solar is harder work than dairy solar. A milking herd gives you a constant, predictable load that absorbs generation all year round, whereas an arable enterprise concentrates its big demand into a few weeks of grain drying and then goes quiet. That does not weaken the case, but it does change the design: an arable array has to be matched carefully to either the drying peak or the daytime baseload, and the spare capacity has somewhere worthwhile to go, whether that is the dairy parlour, a battery, or the grid under the Smart Export Guarantee. Getting that match right is the difference between a six-year payback and a much slower one, which is why we never quote an arable system from roof area alone.

What a typical arable install looks like and how we size it

Arable rooftop systems on a dairy holding usually fall in the 30 to 500 kW band, around 55 to 920 plus panels over 200 to 3,000 plus square metres of grain store and shed roof, with ground-mount potential running to 5 MW and beyond where land and grid allow. Generation ranges from about 27,000 to 460,000 plus kWh a year, saving roughly 6 to 106 plus tonnes of CO2. The defining feature is the grain dryer: a large but seasonal load that runs hard for a few autumn weeks and barely at all the rest of the year. There are two sensible routes, and we model both. The first is to size for the drying peak with a big rooftop or ground array and lean on export income outside the season. The second is to size smaller for daytime baseload and add a battery for the drying weeks. On a mixed dairy farm there is a third advantage: spare summer generation from a grain-store roof can offset milk cooling when the dryer is idle, so the array never has nowhere to send its power. We overlay the crop calendar on your half-hourly meter data and recommend the design that pays best for your particular farm.

Costs, payback and tax relief

A rooftop project typically runs £32,000 to £500,000 plus with a payback near 6 years, helped by the 100% Annual Investment Allowance writing off the cost in year one against the wider farm profit, dairy and arable combined. The Smart Export Guarantee matters more here than on the parlour alone, because the seasonal drying load means an arable array often exports significantly outside harvest, and that export income at four to fifteen pence per kilowatt hour is part of the case rather than an afterthought. The alternative to owning a rooftop system is a land lease, where a third-party developer builds and runs a ground-mount array on your marginal acres and pays you rent, typically £900 to £1,300 per acre per year on a 25 to 40 year term, comfortably above arable rental value, with the developer carrying all the capital and operational risk. Sheep can usually continue to graze beneath the panels, so the land keeps working. Our cost guide compares owning a rooftop system against leasing land side by side.

Funding routes in detail

The 100% Annual Investment Allowance remains the universal route, expensing qualifying plant in year one up to the one million pound cap, which comfortably covers most rooftop arable installs and stacks the relief in a single tax year. The Smart Export Guarantee pays four to fifteen pence per kilowatt hour for exported surplus, and arable load profiles with a seasonal dryer peak tend to export more than a constant dairy load, so SEG carries real weight here. The Sustainable Farming Incentive rewards biodiversity and soil-health actions at roughly five hundred to five thousand pounds per hectare per year, and these stack neatly with a ground-mount lease where sheep graze beneath the panels, letting the same acres earn from generation and environmental actions at once. The Farming Investment Fund can be relevant where solar is paired with an eligible capital item such as a grain dryer, so it is always worth checking for that indirect route. Welsh and Scottish dairy-and-arable farms should check the devolved schemes, the Welsh Rural Investment Scheme and Scottish Rural Development Programme, which often carry higher intervention rates than England.

Compliance and sector considerations

Rooftop PV on agricultural buildings is generally permitted development within the Class A Part 14 size limits, and ground-mount up to 9m by 9m by 4m height also falls under permitted development; anything larger needs full planning permission, with an Environmental Impact Assessment above 5 MW. If any of the arable land or buildings are tenanted you will need landlord consent, and most institutional landlords such as the Crown Estate, the Church Commissioners, the Wellcome Trust and county councils have standard tenant-PV agreements; we provide the lease addendum template for private landlords and run that conversation for you where it helps. Pre-2000 grain stores and sheds often carry asbestos cement roofing under the Control of Asbestos Regulations 2012 that must be replaced before panels go on, and the PV business case can help fund that reclad. The long pole is almost always the grid: a G99 connection on a capacity-constrained rural network can take six to eighteen months, which is why we submit the application early. We hold MCS commercial certification, NICEIC, RECC and TrustMark.

How we approach this kind of project

We pull half-hourly meter data for the whole holding, dairy and arable together, and overlay the crop calendar so the design reflects the autumn drying peak as well as the constant milking load. We model rooftop and ground-mount side by side and recommend the mix that pays best for your farm rather than defaulting to one approach. We carry out a structural survey and an asbestos check before quoting, and we submit the G99 application alongside the survey to start the DNO clock straight away. Where export is constrained, we can design for self-consumption only to compress the timeline. For tenanted ground we handle the landlord engagement and provide the lease addendum. You receive a fixed-price proposal with modelled generation, saving and payback, and the install carries an insurance-backed workmanship warranty, with the work scheduled around harvest so it never clashes with your busiest weeks.

The land-lease decision deserves particular care on a dairy holding, because leasing marginal acres to a developer can look attractive on the rent alone, but it commits the ground for twenty-five years or more and changes what you can do with it. We set out the trade-offs plainly: a lease gives you index-linked income with no capital outlay and no operational risk, while owning a rooftop array gives you cheaper electricity for the dairy and full control of the asset. For many mixed dairy farms the answer is both, an owned rooftop system on the grain store and parlour buildings to cut the bill, and a lease on a genuinely marginal field that earns more under panels than under a poor crop. We model each option against your figures so the decision is made on numbers rather than on a single headline rent per acre.

An illustrative example

As an illustrative composite based on typical UK projects, and not a real named client or real project: a family dairy farm with a large arable acreage had around 12 acres of marginal pasture unsuitable for cropping and leased it to a UK developer for a 1.8 MW ground-mount array of roughly 3,300 panels, generating about 1.7 million kWh a year. The lease ran 25 years at around £1,200 per acre per year with a built-in ratchet, the land continued to graze sheep and youngstock, and biodiversity actions stacked with the lease income under SFI while the dairy buildings carried a separate rooftop array sized for the parlour. The figures are illustrative and depend on your land, grid position and the developer terms available in your region, which is why we model both ownership and lease routes before you decide. The same farm could equally have chosen to own a rooftop array on its grain store and machinery sheds instead, cutting the dairy and drying bills directly rather than taking a rent, and on a different balance of capital and load that might have been the better answer; the point of the modelling is to find which route earns most on your particular numbers.

If the milking side is your priority, start with solar for dairy farms, and if you also run other stock see livestock farm solar. To compare the numbers, read the cost guide and the grants and funding page, then request a free feasibility or read the dairy solar FAQs.