Solar panels on a farm

A farm has roofs and fields that can carry solar panels. Before any are fitted, the farmer works through planning, the connection to the grid, and how the panels will be treated for business rates.

Panels on a farm building roof

In England, solar panels on the roof of a building that is not a house or a block of flats can often go up without a planning application. This is permitted development, under Class J of Part 14 of the permitted development order. Limits apply.

• On a pitched roof, the panels must not stick out more than 0.2 metres from the roof slope.
• On a flat roof, the highest part must not be more than 1 metre above the highest part of the roof.
• The panels must not be within 1 metre of the edge of the roof.
• The rights do not cover a listed building, a building within its grounds, or a scheduled monument.

Larger roof systems, beyond microgeneration, come with an extra step. Before starting, the farmer must ask the council whether it needs to approve the design and appearance, including any glare for neighbours.

Whatever the size, the panels must be placed so they affect the look of the building and the area as little as practicable. They must be removed as soon as reasonably practicable once they are no longer needed.

A small stand-alone array in the yard

Class K allows one stand-alone solar unit within the grounds of a building that is not a house or flats. It must not be more than 4 metres high, or within 5 metres of the boundary. The panels must not cover more than 9 square metres, and no side of the array may be longer than 3 metres. Lower height limits can apply in conservation areas and other protected land, and the right does not cover the grounds of a listed building or a scheduled monument.

A solar farm in a field

For large solar farms on the ground, the government's planning guidance asks councils to weigh several things.

• The guidance encourages large solar farms onto land that has been built on before, or land that is not farmed, as long as it is not of high environmental value.
• On greenfield land, the council asks whether using farmland is necessary, and whether poorer quality land has been used in preference to better land.
• The council also looks at whether the scheme lets farming carry on, or adds to wildlife around the panels.
• Solar farms are normally temporary. Planning conditions can require the panels to be removed and the land restored when they are no longer in use.

Connecting to the grid

The local electricity network operator runs the wires that bring power to the farm. It is a different company from the energy supplier, and the Energy Networks Association lets you look up which one serves your postcode.

The Energy Networks Association explains that a generator of less than 3.68 kilowatts per phase is connected under its document G98. A larger one comes under G99. The application forms go to the local network operator.

Making sure the equipment complies with these rules falls to the customer, who is often the owner of the panels.

Business rates

GOV.UK lists agricultural land and buildings among the properties exempt from business rates. Solar panels can be treated differently.

The Valuation Office Agency's rating manual explains a rule for solar power used on site. In England, until 1 April 2035, renewable equipment is left out of the rateable value where its power is used within the property. The land and supports under it stay rateable. Wales has had the same rule since 1 April 2024.

Power sold to the grid is treated another way. Where most of the power is exported and the system is above 10 kilowatts, the manual says it will normally be a separate property needing its own assessment. Its example is a developer who rents a field for an array that supplies the grid.

Where panels sit on farm property that is otherwise exempt, the manual tells valuers to ask a specialist team for advice.

Useful links

• Permitted development for renewable energy, Part 14 (legislation.gov.uk)
• Renewable and low carbon energy (planning guidance)
• Who is my network operator? (Energy Networks Association)
• Connecting generation to the networks (Energy Networks Association)
• Business rates relief and exempt properties (GOV.UK)
• Rating manual, power generators (Valuation Office Agency)