Solar farm on grade 3b land: an illustrative walkthrough

The land classification survey is the document that decides a ground-mounted solar application on farmland, and it has to be done properly before anything else is commissioned. This solar farm application example is illustrative, built from the pattern these schemes follow rather than from one real case, and it traces a 24 hectare scheme through the evidence that mattered: a detailed Agricultural Land Classification survey returning grade 3b, a landscape assessment that moved two field parcels, and a soil resource plan offered voluntarily.

Grade 3b is not best and most versatile land. Grades 1, 2 and 3a are. That single distinction is worth more to a solar application than any other piece of evidence, and the provisional national mapping is not reliable enough to establish it.

The site and the land classification survey

The provisional mapping showed the site as grade 3, undivided, which tells you nothing useful because grade 3 spans both best and most versatile land and land that is not. A detailed survey was commissioned.

The survey followed the published Agricultural Land Classification guidelines, with auger borings and inspection pits across the site at a density appropriate to a detailed survey, and assessment of climate, soil wetness, droughtiness, texture and depth. The result was grade 3b across about 80 per cent of the area, with two small parcels at 3a on better drained ground on the higher part of the site.

Those two parcels changed the scheme. Rather than argue that a small area of best and most versatile land was acceptable, the layout was redrawn to exclude them, which removed the strongest objection available to the authority before it was made. An Agricultural Land Classification survey is work for a soil scientist, and councils expect a suitably qualified author, so this is not a report to attempt in-house.

One procedural point: the survey has to come first. Commissioning the landscape and ecology work before the classification is known risks assessing a layout that has to change, and that is how fees get spent twice.

Site selection and the sequential argument

National guidance on renewable energy expects developers to use poorer quality agricultural land in preference to higher quality land where a proposal involves greenfield sites. The practical answer is a written site selection exercise, not an assertion.

The one submitted here set out the search area defined by the available grid connection, the sites considered within it, and why each was discounted: two on best and most versatile land, one on a site visible from a National Landscape boundary, one too small for a viable connection. It then explained why the application site was preferred.

Three features made the exercise credible. It named the constraint that defined the search area, so the limits of the search were explained rather than convenient. It included sites the developer had looked at and rejected on commercial grounds, which is more honest than listing only planning reasons. And it gave the classification evidence for the alternatives where it existed, and said plainly where it did not.

The screening position was settled at the same time. Schedule 2 of the Environmental Impact Assessment Regulations 2017 catches installations for the production of electricity where the site area exceeds half a hectare, so a screening opinion was requested and a negative opinion obtained, with reasons, before the application was submitted.

Landscape and visual assessment viewpoints

Panels are low, and the landscape effect of a solar farm is almost entirely about whether you can see across the site and what the boundary treatment does.

Viewpoints were agreed with the case officer before the fieldwork. Twelve in total: four from public rights of way crossing or adjoining the site, three from the nearest lanes, two from the edge of the nearest village, two from higher ground to the south, and one from a listed farmhouse about 600 metres away. Agreeing them in advance removes the argument about whether the assessment chose flattering positions.

The Landscape and Visual Impact Assessment followed the standard methodology and reported two findings that changed the layout. The two northern field parcels sat above a ridge line and were visible from the village edge, so they came out. And the western boundary needed a new hedgerow with trees rather than the post and wire fence proposed, which also served the ecology case.

Cumulative assessment was required because another consented scheme sat 2 kilometres away. That chapter is routinely thin in submissions and routinely picked up by officers, so it was written properly with the consented scheme modelled in.

Glint, glare and the aviation question

A glint and glare assessment was prepared because an aerodrome lay within the consultation distance and because a stretch of road ran along the southern boundary.

The assessment modelled reflections towards the aerodrome approach paths, the road, and the nearest dwellings, across the day and the year. The results were acceptable for the aerodrome and the dwellings, and showed a short period of potential glare towards eastbound drivers on the road in early morning in two months of the year, which was resolved by setting the nearest row back and raising the boundary hedge.

Two things to know about this work. It is specialist modelling and should be prepared by someone who does it regularly, and PlanScope does not produce glint and glare assessments, so it is a separate commission. And the aviation consultees will want the assessment in their own expected format, so ask what that is before it is written.

Biodiversity and the grassland under the panels

Solar schemes are unusually good at biodiversity net gain, because the land under and between panels can be managed as species-rich grassland for the life of the scheme, and the baseline on intensively farmed arable is low.

A Preliminary Ecological Appraisal established the habitat baseline and found arable with species-poor hedgerows, no protected species constraints beyond nesting birds in the hedges, and one pond 80 metres beyond the boundary that triggered a newt assessment.

The biodiversity gain plan relied on three measures: a grassland seed mix under and between the rows with a cutting and grazing regime, hedgerow gapping-up and new hedgerow with trees on the western boundary, and skylark plots in the retained arable margin. The statutory metric was completed by the ecologist, and the scheme comfortably exceeded the 10 per cent requirement, which is a familiar outcome on this kind of development.

The 30 year management commitment is the part that needs drafting carefully, because the solar permission and the biodiversity obligation have to run for compatible periods. A mismatch between a 40 year operational permission and a 30 year habitat management obligation is manageable, and a mismatch the other way is not.

Decommissioning and soil reinstatement

The permission sought was temporary, for 40 years from first export, with the site to be decommissioned and restored afterwards.

A soil resource plan was offered with the application even though none was required. It recorded the soil profile from the classification survey, set out how soils would be protected during construction, specified that trafficking would be restricted to defined routes with ground protection in wet conditions, required pile driving rather than concrete foundations where ground conditions allowed, and committed to reinstating any disturbed soils to their recorded profile at decommissioning. PlanScope does not generate soil resource plans, so this came from the soil consultant who did the classification work.

Offering it had a practical effect beyond goodwill. The case officer's report used it to answer the objection that the land would be lost to agriculture, by pointing to the evidence that the soil resource would be preserved and that grassland management under panels generally improves soil organic matter compared with continuous arable.

Conditions secured at determination

The permission was granted with conditions worth anticipating on any scheme of this kind.

• A 40 year temporary period from the date of first export, with a decommissioning and restoration scheme to be submitted and approved at least 12 months before the end of that period.
• Development in accordance with the approved layout, which was the revised one excluding the two 3a parcels and the two northern fields.
• Landscape and ecology management plan to be approved before the start of construction and implemented for the life of the scheme.
• Construction environmental management plan including soil handling, following the submitted soil resource plan.
• Glare mitigation through the approved setback and boundary planting, to be retained.
• Construction traffic routing and hours, with the access improved before any other works.

A related walkthrough on a solar array on agricultural land and the classification question covers the classification issue in its own right, including what happens when the survey comes back higher than expected.

You can see which reports a renewable energy scheme is likely to need and draft the planning and landscape documents from your own site details, then have the classification, ecology and glare work carried out by qualified professionals.

For specialist technical reports, qualified professional input may be required. 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.