Renewable energy on a farm: scale, grid and landscape

Farm solar wind planning decisions turn on three things long before anyone looks at the design: the quality of the soil you are covering, whether a grid connection exists at a sensible cost, and what the scheme does to views from the surrounding area. Get those three wrong and no amount of hedgerow planting rescues the application.

Scale is the decision that sets everything else. A 250 kilowatt array behind the grain store is a different animal from a 20 hectare solar farm on a tenanted field, and the planning route, the evidence base and the cost of getting it wrong all change with it.

Deciding the scale the holding can support

Start from the connection, not from the available land. The size of scheme you can build is limited by what the distribution network will accept at your point of connection, and that figure is published or obtainable before you spend anything on design.

Three broad tiers, with different planning consequences.

Behind the meter generation sized to the holding's own demand. Rooftop arrays on agricultural and commercial buildings may fall within permitted development, and our note on rooftop solar on commercial buildings under Class J sets out the limits. Ground mounted arrays on a farm almost always need permission, whatever the size.

Farm scale export schemes, typically a few hectares, determined by the local planning authority as a full application. This is where most diversification projects sit.

Schemes large enough to cross the nationally significant infrastructure threshold, which are determined by the Secretary of State under the Planning Act 2008 rather than by the council. The threshold for onshore generating stations has been changed by secondary legislation, so check the current figure before assuming a scheme sits with the council.

Wind is a separate calculation entirely, because a single turbine of any useful output is visible for kilometres and the policy tests have shifted between recent editions of the National Planning Policy Framework. The farm scale wind turbine route deserves a read before choosing between wind and solar on the same holding.

Best and most versatile land and the soil argument

This is the argument that decides rural solar applications, and it is winnable with evidence.

National policy expects poorer quality agricultural land to be used in preference to higher quality land, with best and most versatile land meaning Grades 1, 2 and 3a under the Agricultural Land Classification. The problem is that the published Natural England provisional maps were produced at a broad scale and split Grade 3 without distinguishing 3a from 3b. A provisional map showing Grade 3 tells a case officer almost nothing, and it is frequently read against the applicant.

So commission a site specific survey. An Agricultural Land Classification assessment carried out to the published guidelines by a soil scientist, with auger borings and profile pits at an appropriate density, produces a grade map for your fields. Where that survey shows 3b, you have the central objection answered on the facts.

Two further points that officers respond to:

• Panels are mounted on driven piles, not concrete, and the soil beneath is not sealed. The land can be grazed, and the use is reversible at the end of the permission.
• A temporary permission with a restoration condition means the agricultural capability is retained rather than lost, which is a materially different proposition from building houses on the same field.

The survey has to be done at a time when the ground is workable, which in practice rules out the wettest months. Programme it a season ahead.

Grid connection capacity and its planning footprint

The connection is a commercial matter, but it has a planning footprint that applicants routinely leave out of the application.

What the council needs to see:

1. The point of connection and the cable route, shown on a plan, including any land outside your ownership.
2. The substation and switchgear compound, with dimensions, materials, fencing and any acoustic enclosure.
3. Any new poles, transformers or overhead line diversions.
4. Whether the network operator will carry out works under its own permitted development rights, and what remains for the council to permit.

The compound is the part that gets refused. A prefabricated grey building with palisade fencing in the middle of open countryside is a landscape objection in its own right, and it is far easier to deal with by siting it against existing farm buildings than by planting round it later.

Cable routes raise their own issues. Trenching across fields can hit archaeology, land drainage and hedgerow crossings, so expect an archaeological watching brief condition and a land drainage reinstatement scheme. Where the route crosses a watercourse or a public right of way, those consents are separate.

Battery storage is increasingly proposed alongside generation, and it brings fire safety, noise and access considerations that solar alone does not. Our note on battery energy storage planning issues covers what decides those applications.

Landscape and visual assessment expectations

For anything beyond a small array, expect the council to want a Landscape and Visual Impact Assessment prepared to the third edition of the Guidelines for Landscape and Visual Impact Assessment.

What a usable assessment contains:

• A zone of theoretical visibility, then a reality check on the ground, because hedgerows and buildings screen far more than a bare terrain model suggests.
• Viewpoints agreed with the case officer in advance, including from public rights of way, nearby dwellings and any designated area within the study radius.
• Photomontages at the correct focal length, with a winter case where deciduous screening is being relied on.
• A cumulative assessment covering consented and applied for schemes nearby, which is the section most often missing and the one most often used to refuse.
• Mitigation that is part of the design rather than added at the boundary: set backs from hedgerows, panel height reduced at the visible edge, existing hedges thickened and gapped up.

Where the holding sits in or near a National Landscape or National Park, the bar rises sharply and the great weight given to conserving those designations has to be answered directly rather than sidestepped.

Glint, glare and aviation safeguarding

A glint and glare study is standard for solar near an aerodrome, a flight path or a busy road, and its cost is small relative to the risk of a late objection.

The study models reflections from the panel surfaces against receptor positions: control towers, approach paths, dwellings and road users at particular times of day and year. Where an aerodrome safeguarding zone covers the site, the operator will be consulted, and the Ministry of Defence safeguards its own sites. Anti reflective coatings, panel tilt limits and screen planting are the usual mitigations.

Do not leave this to the consultation stage. An aerodrome objection arriving in week six of an eight week determination almost guarantees a refusal or a long extension of time.

Access, construction traffic and cabling routes

Farm accesses designed for a tractor and trailer are not designed for articulated deliveries of panel pallets or, for wind, abnormal indivisible loads carrying blades.

The highway authority will want swept path analysis for the largest vehicle, visibility splays at the access, a construction programme with vehicle numbers by phase, wheel washing, and a route agreed from the strategic network. A Construction Traffic Management Plan is normally conditioned even where it is not required at validation.

As an illustrative example, a 15 hectare array on a holding served by a 300 metre single track lane might need a passing bay, a temporary widened bellmouth, a restriction to deliveries outside school times and a condition survey of the lane with a repair obligation. None of that is unusual. All of it costs money that belongs in the appraisal rather than in a surprise later.

Decommissioning and restoration conditions

Solar permissions are normally granted for a defined period, commonly 25 to 40 years, with conditions requiring removal of the equipment and restoration of the land within a stated period after generation ceases.

Write the restoration scheme yourself rather than accepting standard wording. It should cover removal of piles, cables and compound bases, a soil handling method that protects structure, reinstatement of land drainage, and a defined agricultural end state. Where a council asks for a financial bond, that is a negotiation about the strength of the covenant rather than a policy requirement, and it is reasonable to ask what the bond is protecting against.

Biodiversity net gain applies to these schemes, and solar farms are unusually good at delivering it: species rich grassland under and between panels, managed without the inputs an arable rotation needs, can produce a substantial uplift on the statutory metric. Build that into the design from the start and it becomes an argument for the scheme rather than a cost.

This is general guidance, not legal advice. Grid capacity, agricultural land grades and policy tests all turn on site specific facts, so check the position with your local planning authority or a qualified professional before relying on it. For specialist technical reports, qualified professional input may be required.

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