Solar farm planning permission on farmland: the tests

Solar farm planning permission on farmland turns on three questions long before the design is fixed: who decides the application, what grade the soil is, and who can see the site. Get the land classification wrong and the scheme is arguing against national policy on the best and most versatile land from the first paragraph of the officer report. Get the viewpoints wrong and the landscape objection lands late, when the grid offer is already paid for.

A ground-mounted array is development. There is no permitted development right for a commercial-scale solar farm on agricultural land, and the consent route depends on capacity.

Which consent route applies

Below the nationally significant infrastructure threshold, the local planning authority determines a full planning application in the ordinary way. Above it, the scheme is decided by the Secretary of State under the Planning Act 2008 through a development consent order, with the Planning Inspectorate running the examination.

The capacity figure that separates the two routes has been changed since the Planning Act was passed, so check the current threshold in the Act as amended rather than repeating a number from an older article. Schemes are sometimes designed to sit just under it, and an inspector will notice a scheme that has been artificially split into parcels to avoid the higher route.

Battery energy storage co-located with the array is usually applied for at the same time. It brings its own consultation with the fire and rescue service, its own noise source in the form of cooling plant, and its own layout constraints around separation distances between containers.

Agricultural land classification and best and most versatile land

The Agricultural Land Classification system grades land 1 to 5. Grades 1, 2 and 3a are best and most versatile. Grade 3 is split into 3a and 3b, and the provisional mapping published by Defra does not make that split, which is why a site-specific survey matters so much on a Grade 3 holding.

National policy asks decision makers to take the economic and other benefits of best and most versatile land into account and, where development of agricultural land at scale is shown to be necessary, to prefer poorer quality land. That is not a prohibition. It is a weighting that a well-evidenced scheme can meet, and the way to meet it is with a proper survey rather than an assertion.

A survey to the published Ministry of Agriculture, Fisheries and Food 1988 revised criteria involves auger borings and soil pits across the site, assessed for climate, site and soil factors including wetness, droughtiness, depth and stoniness. It has to be done by a soil scientist, in conditions that are neither waterlogged nor baked, which puts a season on it. An agricultural land classification report that finds the site is predominantly subgrade 3b removes the single most common reason for refusal on farmland arrays.

Where the site does include best and most versatile land, the case has to be built on necessity and on reversibility: the panels sit on driven piles, the soil is not sealed, and the land can return to arable use at the end of the permission.

Landscape and visual impact

Solar farms are low, wide and reflective. That combination produces a different visual effect from a building of the same footprint, and the assessment has to deal with it honestly.

A landscape and visual impact assessment prepared to the GLVIA3 method should cover the landscape character baseline, the receptors, and a set of viewpoints agreed with the case officer before any photography. Public rights of way crossing or adjoining the site deserve particular attention, because a footpath user at 50 metres experiences the development quite differently from a motorist at 500 metres.

Mitigation on these schemes is mostly hedgerow and hedgerow tree planting, set-backs from field boundaries and lanes, and sensitive fence and CCTV design. Deer fencing at 2 metres with rotating cameras on poles reads as industrial. A stock fence set behind a reinforced hedgerow does not.

Cumulative effects are the assessment most often skimped. If two consented arrays sit within a few kilometres, the officer will ask about the combined effect on the same viewpoints, and an assessment that ignores them invites a holding objection.

Glint, glare and safeguarding

Reflection from panels is assessed separately from landscape impact. A glint and glare study models the geometry of the sun, the panels and the receptors through the year and reports where and when reflections could reach air traffic, road users, railway signallers or dwellings.

Aerodrome safeguarding is the consultation to programme early. Licensed aerodromes, Ministry of Defence sites and some smaller airfields hold safeguarding zones, and the operator or the Civil Aviation Authority may need to see the modelling before commenting. National Highways will look at reflection towards the strategic road network, and Network Rail at signal sightlines.

This is specialist modelling work carried out by a consultant with the software to do it. Treat it as an input to the planning statement rather than something the planning team can write.

Ecology, biodiversity net gain and the land under the panels

Mandatory biodiversity net gain applies to solar schemes as it does to any other development caught by the Environment Act 2021 regime, and arrays are unusual in that the gain is often straightforward to deliver on site. Land beneath and between rows can be sown with a species-rich grassland mix and managed by grazing or a low-intensity cut and collect regime for the life of the permission.

That advantage only materialises if the biodiversity net gain assessment is built into the layout from the start, with realistic row spacing, a management plan someone will actually fund, and a habitat condition target that a grazier can hit. The statutory metric has to be completed by a competent person under the Environment Act 2021 regime, and the biodiversity gain plan is approved by the local planning authority before development begins.

The baseline ecology work still applies. A preliminary ecological appraisal establishes what is there, and where hedgerows, ponds, barns or rough grassland are affected, protected species surveys follow with their own seasonal windows. Great crested newt work in particular has a narrow spring window, and missing it can cost a full year.

Grid connection, access and construction traffic

The grid connection is often the longest lead item on the whole project and sits partly outside the planning application. Cable routes to the point of connection may be consented separately, and the substation compound needs to appear on the planning drawings with its own visual and noise treatment.

Access is where rural schemes get bogged down. Panels, transformers and piling rigs arrive on long vehicles, and a single-track lane with soft verges and mature hedgerows on both sides is not a construction route without works. Swept path analysis, temporary passing bays, wheel washing and a routing agreement all belong in a construction traffic management plan. Where the scheme needs a new or widened field entrance, the highway authority's requirements for a new vehicular access onto a rural lane apply in the same way as they would for a house.

Agree the construction hours, the abnormal load schedule and the mud-on-road controls before the parish council raises them.

Temporary permission, decommissioning and conditions

Solar permissions are normally time-limited, with a condition requiring the site to be decommissioned and the land restored at the end of the period. Expect conditions covering the decommissioning method, soil handling and restoration, the landscape and ecology management plan and its funding, construction hours, lighting, and details of the fencing and cameras.

Two of those repay attention at draft decision stage. A decommissioning bond or a section 106 obligation may be sought, and the ecology management plan will bind the landowner for decades, so the wording has to match what the farm business can deliver.

This is general guidance, not legal advice. Check the position with your local planning authority or a qualified professional before relying on it.

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