Walkthrough: solar farm on lower grade agricultural land

A solar farm planning application pack on lower grade agricultural land stands on one document more than any other, and it is not the landscape assessment. It is the agricultural land classification survey, because national policy expects poorer quality land to be used in preference to the best and most versatile, and the published maps are not accurate enough to prove which you have. This walkthrough follows an illustrative scheme of roughly 28 hectares of ground mounted panels on three arable fields, with a grid connection 900 metres away and a small aerodrome 4 kilometres to the south-west. The figures and the sequence are illustrative rather than taken from a decided application.

The site and the land classification evidence

Grades 1, 2 and 3a are best and most versatile land. Grades 3b, 4 and 5 are not. The whole policy argument for a greenfield solar scheme rests on which side of the 3a and 3b line the fields fall, and that line is a matter of soil wetness, droughtiness, depth and texture rather than of what the farmer thinks the land yields.

The published agricultural land classification mapping for England is a strategic product at a broad scale, and it does not distinguish subgrade 3a from 3b at all. A great deal of land shown as Grade 3 on those maps turns out to be 3b on survey, and some turns out to be 3a. So a scheme that relies on the published map has no evidence either way, and an officer cannot use it.

An Agricultural Land Classification survey is therefore the first substantive piece of work. It is a field survey, carried out by a soil scientist to the published grading guidelines, with auger borings on a grid across the site, soil profile descriptions, and climatic data interpolated for the site. It produces a plan showing the grade and subgrade of each parcel and a stated proportion of best and most versatile land.

Commission it before you take the option to a decision. If the survey returns predominantly 3a, the scheme is a different and much harder proposition, and finding that out early is worth the fee.

Why the survey has to come before the layout

Two reasons. First, the grading result determines the policy case, and the policy case determines whether the scheme is worth pursuing at this scale on this land. Second, where a site is mixed, the survey lets you design the layout to avoid the better parcels, which is a far stronger position than arguing that a uniform loss is acceptable.

The survey also answers a question that comes up at committee. Panels on posts leave the soil in place, and sheep grazing beneath them is common, so the loss of agricultural land is temporary and partial rather than permanent. Say that plainly, quantify the area actually occupied by foundations, tracks and substation, and commit to a soil management plan for construction so that compaction does not make the reversal notional.

Landscape and visual assessment scope

Solar farms are low, extensive and reflective, which makes them a different landscape problem from a wind scheme. The effects are concentrated in near and middle distance views, from public rights of way crossing or adjoining the site, and from residential properties on the same level as the array.

Scope the Landscape and Visual Impact Assessment with the authority's landscape officer before fieldwork. Agree the study area, the viewpoints, the seasons for photography and whether photomontages or wireline visualisations are wanted. A zone of theoretical visibility for a 3 metre high array is small and irregular, which is an advantage worth demonstrating properly.

Screening is where these schemes are won. Existing hedgerows reinforced and allowed to grow to a stated height, new native hedgerow planting with a defined establishment period, and setbacks from footpaths achieve more than any argument about acceptability. Set the planting out on a drawing with species, stock size and a management commitment, and be honest about the years it takes to be effective.

Include the substation, inverter stations, security fencing, CCTV columns and the battery compound if there is one. Those are the vertical elements, and they are what appears in objections.

Glint and glare

A glint and glare assessment models reflected solar geometry from the panel surfaces towards identified receptors through the year, and reports where and when reflection could occur and for how long.

Cover four receptor groups. Dwellings and their windows. Road users on the approaches where a driver would be looking towards the array. Railway drivers and signal sighting where a line passes nearby. And aviation, meaning any aerodrome within the safeguarding distance, plus the approach and circuit patterns rather than just the runway.

Aviation is the one that changes the programme. Where an aerodrome lies within the safeguarding area, consult the operator early, and consult the Civil Aviation Authority or the Ministry of Defence where their interests are engaged. An assessment that concludes no effect is straightforward. One that identifies a reflection towards an approach path needs a design response, usually panel orientation or tilt limits or screening, and that response has to be agreed rather than asserted.

Modern panels are designed to absorb rather than reflect, which helps. It does not remove the need for the assessment, because the receptor geometry is what matters and the authority will want to see it modelled.

Ecology, hedgerows and biodiversity net gain

Arable land is usually low in biodiversity value, which makes solar schemes among the easiest development types to deliver biodiversity net gain on. Grassland creation beneath and between the arrays, managed by grazing or a cutting regime, can produce a gain well above the statutory minimum, and the 30-year management period fits a scheme whose permission is time limited anyway.

Mandatory biodiversity net gain under the Environment Act 2021 requires a 10 per cent gain, the statutory metric to be completed by a competent person and a biodiversity gain plan approved by the local planning authority. A Biodiversity Net Gain Assessment is a report type where a competent person is legally required, and a draft is a starting point for that person rather than a substitute.

Hedgerows are the constraint that catches people out. Removal of a hedgerow may require notification under the Hedgerows Regulations 1997, and important hedgerows under those Regulations cannot be removed without consent. Cable routes and access tracks want to cross hedgerows, so design the crossings to use existing gaps.

Ground-nesting birds are the other one. Skylark and lapwing use open arable, and a preliminary ecological appraisal should cover them with survey work in the breeding season if the appraisal identifies potential. Construction timing conditions follow.

Grid connection and the cable route

Establish who builds the cable and under what consent. In many schemes the network operator carries out the connection works using its own permitted development rights, which keeps the route out of your application. In others the route forms part of the development and needs permission, with its own archaeology, hedgerow crossing and reinstatement issues.

Either way the route is a real constraint and not an afterthought. It crosses land you may not control, it needs easements, and its archaeological risk is often higher than the array site because it is a linear trench through undisturbed ground. Where the county archaeological adviser asks for geophysical survey, expect it to cover the cable corridor as well as the field, and an Archaeological Desk-Based Assessment should treat the two together.

The submitted pack

The application for this illustrative scheme contained a Planning Statement, a Design and Access Statement, the site and layout drawings including fencing, tracks, substation and inverter positions, an agricultural land classification survey, a Landscape and Visual Impact Assessment with photomontages from agreed viewpoints, a landscape and ecological management plan, a Preliminary Ecological Appraisal with breeding bird survey, a biodiversity net gain assessment and metric, a glint and glare assessment, an archaeological desk-based assessment with geophysical survey results, a flood risk and drainage note, a Construction Environmental Management Plan including soil handling, a transport statement covering construction deliveries and abnormal loads, and a decommissioning and restoration statement.

An environmental impact assessment screening request went in first. Installations for the production of electricity fall within Schedule 2 to the Environmental Impact Assessment Regulations 2017 where the development area exceeds 0.5 hectares, so screening is the normal starting point for any solar farm. Where capacity exceeds the statutory threshold for a nationally significant infrastructure project, the route changes entirely and the Secretary of State determines it; that threshold has been altered recently, so verify the current figure before assuming which regime applies. The comparable sequence for a smaller rural proposal is set out in our walkthrough of stables and a menage in the Green Belt.

Decommissioning and restoration

Permissions for solar farms are normally granted for a fixed period, with a condition requiring the panels, foundations, tracks, fencing and buildings to be removed and the land restored at the end of it. Read the restoration condition carefully, because a requirement to restore to the condition recorded in a pre-development soil survey is only meetable if that survey was actually carried out.

Offer the survey. A soil resource survey before construction, a soil management plan during it, and a restoration specification tied to both, gives the authority the comfort it wants and gives you a defensible baseline. Some authorities also seek a financial guarantee for decommissioning through a planning obligation, and it is better to propose a mechanism than to resist the principle.

This is general guidance, not legal advice; check the position with your local planning authority or a qualified professional before relying on it. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval. For specialist technical reports, qualified professional input may be required.

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