What solar panels for farms cost, and what moves the number

How much do agricultural solar panels cost in the UK?

Agricultural solar panels cost whatever it takes to get them safely onto your particular buildings and connected to your particular supply, so two holdings farming the same acreage a mile apart can differ by a wide margin, and the difference is almost never the solar panels themselves.

It is the roof covering, the state of the incoming supply, the distance from the building to the intake position, and what the distribution network operator will let the farm export. An agricultural solar panel cost is therefore a holding specific number, and every guide that prints one rate is describing an average rather than your yard.

Published figures for agricultural solar panels in the United Kingdom are taken across a mixed population of buildings, from new steel framed grain stores to sixty year old Dutch barns, so they describe nobody's farm in particular. We would rather give you the structure of the number than a rate you cannot rely on. Every agricultural solar panel installation quote breaks into the same six lines, and once you can see those lines you can compare two quotes properly instead of comparing two headline rates built on different assumptions.

It also lets you compare two installers on the same basis. A solar panel installer who prices a farm from a satellite image is pricing the roof they hope to find, and a panel installer who has walked the yard is pricing the one that is there. The gap between those two agricultural solar panel installation cost estimates is not a discount. It is a set of installation costs that have been left for later.

What sits inside a farm solar quote

A kWp, or kilowatt peak, is the rated output of a solar array under standard test conditions, and it is the unit every agricultural solar quotation is priced against.

A farm solar panel quote is a construction price, not a product price. What it costs to install solar panels on a farm building is mostly what it costs to get to the roof, fix to it safely and cable back to the intake position. Most of the variation between two quotes for the same grain store is in how each one handles access, the roof covering and the electrical works, not in the solar panel itself. Ask for the price broken into these six lines, because that is the only way to see what you are actually comparing.

The order matters as much as the total. A quotation that prices the solar panel and the inverter precisely and leaves access, groundworks and the connection as provisional sums has priced the easy half. Those three lines are where the money to install solar on a working holding actually goes, and they are the ones a survey exists to pin down.

Read the six lines as installation costs rather than as a shopping list. The solar panel is a traded commodity sold by the watt, so two quotes rarely differ much on it. What separates them is the labour and the equipment needed to install solar panels safely on a building that was put up to house a combine rather than to carry an array. That is where a farm solar panel price is won or lost.

Why system size changes the price per kWp

System size is the strongest single lever on the price per kWp, because design time, the grid connection application, mobilisation, access equipment and commissioning are close to fixed whether the solar system is 30 kWp or 500 kWp.

Spread those over more panels and the rate per kWp falls, which is why a long poultry unit usually prices better per kWp than a small machinery store on the same holding. System size is the first thing that moves agricultural solar costs, and it moves them before anyone has chosen a solar panel.

The effect is not unlimited. It flattens once the fixed costs are diluted, and it reverses if the system grows past what the incoming supply or the network operator will accept, because at that point the farm is buying a connection upgrade as well as an array. That is where the price per kWp starts climbing again, and on a rural network it climbs earlier than it does on an industrial estate.

This is also why sizing to the roof and sizing to the load give different answers. Farm roofs will usually take more panels than the holding consumes. Whether that surplus is worth installing depends on the export rate and on the energy the enterprise actually uses in daylight, which is the arithmetic further down this guide.

Fibre cement roofs and the asbestos survey

Fibre cement sheeting is the single largest swing in agricultural solar costs, ahead of the panel price and ahead of the system design, because sheet laid before 2000 may contain asbestos and has to be surveyed before anyone accesses the roof.

A refurbishment and demolition survey establishes what the covering is, and the finding drives the method statement, the mounting design and the programme. Fibre cement is also a fragile roof, so the access provision is different from a modern steel sheet even where the survey comes back clear.

The second question is remaining sheet life. A roof with ten years left carries solar panels for most of their design life. A roof with three years left means paying to remove and refit the array later, so re-sheeting first is usually the cheaper order of operations even though it reads as the expensive one on day one. Purlin centres, the spacing between the steel or timber members carrying the sheet, set the mounting design and therefore the price. Our roof survey page sets out what gets measured and why each item matters to the cost.

Three phase supply and the cable run across the yard

A three phase supply is what an agricultural solar array of any scale needs to connect into, and a great many holdings run on a single phase service sized decades ago for a house, a workshop and a milking parlour.

Where three phase is absent or weak, the distribution network operator quotes separately for bringing it in or reinforcing it, and that quotation sits outside the installer's price. It is the cost most often discovered late, and it is the reason we establish the supply position before anyone designs a system size.

The second half of the same problem is distance. Farm buildings are spread out in a way an industrial unit never is, so the run from a grain store or a poultry unit back to the intake position can be hundreds of metres of trenching, ducting and armoured cable. That is groundworks, priced by the metre and by the ground conditions, and on a spread out holding it can exceed the mounting line. Where several buildings are in play, which one carries the array is a cost decision as much as a roof decision.

Seasonal load decides the payback on agricultural rooftop solar

Self-consumption is the share of generation the holding uses on site rather than exporting, and on a farm it is decided by the season as much as by the day.

Every unit the panels make goes one of two ways. A unit you use displaces energy you would otherwise buy, so it is worth your full delivered day rate including the standing and non commodity charges on the bill. A unit you export earns the tariff your supplier offers under the Ofgem Smart Export Guarantee, which is materially lower.

Farm load is lumpy in a way commercial load is not. Grain drying runs hard for a few weeks in late summer and stops. Milk cooling and vacuum pumps run every single day at roughly the same hours. Poultry and pig ventilation tracks the weather, so it peaks in the same months the panels are most productive. A dairy and an arable holding with identical roofs and identical arrays will have very different paybacks purely because of when the load falls.

That is why we ask for twelve months of consumption data before anyone models anything. The split between self-consumption and export is measured from the meter history, not assumed from a sector average, and it is the single biggest driver of whether farm solar panels are worth it on your holding.

What a ground mounted array costs per acre

A ground mounted solar array is priced by its grid connection and its groundworks first and by its panels second, which is the reverse of how most per acre guides present it.

The distribution network operator decides what the local network can take and what reinforcement it wants paid for, and on a rural feeder that answer swings the total more than the modules do. After it come the civils: access track, trenching, piling or ballast depending on the ground, fencing and security. Solar farms of any size are largely a civils and connection job with panels on top.

That is why per acre guides to solar farms vary so widely. Two fields a few miles apart can differ by a large multiple on the same acreage because one sits beside a substation with capacity and the other does not. Ask any developer quoting solar farms what connection offer the figure assumes, and the conversation becomes a real one.

Ground mount also carries a planning route that rooftop solar usually avoids, and it takes land out of, or into shared use with, production. Where grazing or cropping continues between and beneath the rows, the arrangement is agrivoltaics, and the design changes with it. Both of those are covered properly on our pages for solar land rent and agrivoltaics.

Do you need planning permission for solar on agricultural land?

Rooftop solar on a non domestic building in England is capable of being permitted development under Class J of Schedule 2 Part 14 of the Town and Country Planning (General Permitted Development) (England) Order 2015, subject to the conditions and limits in that class.

Prior approval from the local planning authority is required above a stated capacity threshold, and the order has been amended more than once in recent years, so the current text rather than a blog summary is what to work from. A ground mounted array falls under a different class with much tighter limits, which is why anything beyond a small stand alone installation normally needs a full planning application.

Designated land, listed buildings and anything within a curtilage change the answer again, and a holding inside a National Park or a National Landscape should assume it needs a conversation rather than an assumption. We raise the planning position at survey stage because a planning answer arriving after the quotation is one of the two most common reasons a farm solar project stalls. The other is the grid connection.

Capital allowances and the after tax cost of farm building solar PV

Solar panels are plant and machinery that HMRC treats as special rate pool expenditure, and the special rate pool is the capital allowances pool carrying a lower writing down rate than main rate plant.

The guidance sits in the Capital Allowances Manual at CA22335. That classification matters because the reliefs available to special rate expenditure are not the same as those for main rate plant, and it changes the cash cost of a farm solar system in the year you buy it. The Annual Investment Allowance and the first year allowance for special rate expenditure are the two routes worth putting in front of your accountant.

We are not accountants and we will not tell you what the business can claim. We will tell you to put CA22335 in front of yours before signing anything, and to model the payback both before and after relief. A scheme that only works after tax relief is a different proposition from one that works on the energy alone. Where a partnership or a contract farming agreement is in place, who owns the array and who claims the allowances is a question to settle before the order, not after.