Solar panels for farm buildings and business roofs.

Solar panels on farm sheds

Portal-frame sheds and grain stores tend to have the widest unshaded roofs on a farm, which is what an array needs.

A shed whose ridge runs east to west gives one long south-facing slope. A ridge running north to south works as well, with panels on both faces catching the morning and the afternoon sun.

The catch is the sheeting. Many older farm roofs are fibre-cement, and HSE says most farms have some asbestos-containing material, such as asbestos-cement roof sheets. Under the Control of Asbestos Regulations, the farm's owner or tenant has to know where it is and what condition it's in.

Sheeting in good condition is often best left alone, but drilling and fixing into it is work on asbestos and has to be planned as such. Replacing old sheets before the panels go on gives them a roof that should last as long as they do.

Fibre-cement sheets and rooflights are fragile as well. Falls are the second biggest cause of death in farming, and HSE's advice is to treat a roof as fragile until it's been shown otherwise and to work from below or from a platform wherever possible. Walking the purlins is out.

Planning for solar on farm and business roofs

Panels on a building that isn't a house come under their own class of permitted development. On a pitched roof they have to stay near the line of the slope, and on a flat roof there's a height limit and a gap to keep from the edge.

Listed buildings, the land around them and scheduled monuments are excluded. A larger array, over the size the law counts as microgeneration, needs the council's prior approval as well. The council looks mainly at glare on the neighbours and has a set time to decide.

The farmhouse is a home, so solar for the farmhouse roof follows the rules for houses, from planning through to VAT.

Wiring solar into a farm's electrics

Farm buildings come under BS 7671's Section 705, written for agricultural premises because damp, dust and corrosive vapours attack equipment, and livestock can reach it. Cabling from an array needs the same protection as the rest of the farm's electrics, kept out of reach of stock and away from rats.

Section 705 calls for RCD protection on final circuits, and it treats fire as a particular risk in buildings holding hay, straw or feed. An inverter belongs somewhere clean and dry, well away from bedding and dust.

Where the panels feed a shed with its own board, that board must have space for the new supply and protective devices rated for two-way power flow, the same rule a house has to meet.

Where panels go on more than one building and feed back to one board, cables cross the yard. Buried cables on a farm need to be deep enough to stay clear of vehicles and cultivation, with their routes recorded so nobody digs into them later.

Bigger arrays are often connected across three phases. If the farm runs on single phase, a three-phase supply for the yard is a separate piece of work, best sorted out before the solar is planned.

Where solar pays on a farm or a small business

Solar works hardest where the power is used while it's being made. Milk cooling and parlour pumps, ventilation fans, grain drying and a workshop running through the day all line up with daylight.

Grain drying is seasonal, so on an arable farm the summer surplus can run well ahead of what the yard uses in winter.

Businesses that are busiest in daylight and in summer fit the same pattern, such as shops with chillers and independent holiday and caravan parks, where laundries and amenity blocks draw most of their power while the panels are producing.

Where there's a big load after dark, such as fans in a poultry shed, storing the day's surplus in a battery carries it into the night.

Weigh up the building's future as well. Panels are a long-term fixture, so a shed that is due for replacement or a change of use is better dealt with first.

VAT, business rates and insurance

The zero rate of VAT on solar applies to homes and to buildings used for a charitable purpose. Panels on a farm building or business premises are charged the standard rate of VAT, which a VAT-registered business normally reclaims.

Business rates are a different matter. In England, rooftop solar and battery storage used for on-site generation are exempt from business rates, under an exemption for renewable plant and machinery.

Tell your insurer before an array goes on a business roof. Many insurers follow the joint code of practice on fire safety for rooftop PV, known as RC62, and some add their own conditions about where the panels can sit.

Defra's Improving Farm Productivity grant has paid towards rooftop panels and batteries on farm buildings, with ground-mounted arrays left out. When GOV.UK last updated the guidance, in March 2026, its second round was closed, so check for a later round before counting on one.