Solar farm land calculator: acres, megawatts and rent for UK landowners

Updated 20 October 2026 · SEO Dons Editorial

Quick answer: on DESNZ figures a new UK ground-mount solar farm needs roughly 4 to 5 acres per megawatt, and published land-agent rents run from about £800 to £1,100 per acre per year, index-linked. So 100 acres could host somewhere near 20 to 25MW and be offered a base rent of roughly £80,000 to £110,000 a year, if the whole area were suitable, which it rarely is. Enter your own acreage below. It is a first filter before you speak to a land agent, not a valuation.

Assumptions: 1.6 to 2 hectares per megawatt for new schemes (DESNZ), 0.4047 hectares per acre, rent £800 to £1,100 per acre per year (Arup for DESNZ, July 2025; Stephens Scown 2023; Brown & Co 2024), applied to the whole area entered. No data you type into the calculator is stored; it is sent only if you submit the enquiry form below.

How the calculator works

The calculator does two multiplications, and both rest on published figures rather than our own estimates. The first converts acres to hectares and divides by the land a new scheme needs per megawatt. The Department for Energy Security and Net Zero (DESNZ) measured a median of 2.25 hectares (5.6 acres) per MW across 872 existing UK ground-mount sites, and estimates 1.6 to 2 hectares (4 to 5 acres) per MW for new schemes built with today’s more efficient panels. We use the new-scheme range because a developer approaching you now will be proposing modern kit. The footprint includes the gaps between rows, access tracks and the fenced margin, so it is a gross figure for the fenced site, not the panel area alone.

The second multiplies the acreage by a rent range. UK land agents and law firms publish figures, and they cluster closely: the Arup survey for DESNZ (July 2025) put land and rental costs at £800 to £1,000 per acre per year; Stephens Scown quoted £850 to £1,100 for subsidy-free solar in 2023; Brown & Co cited about £1,000 an acre in June 2024; and Fisher German was quoted in Farmers Weekly in July 2024 at up to £3,000 per hectare, about £1,200 per acre. We show £800 to £1,100 because it spans the survey and the two most-quoted legal and agency figures without leaning on the highest outlier. Rents are negotiated, almost always index-linked, and sometimes topped up with a revenue share, so the result is a base-rent guide.

The result is therefore an upper envelope. It assumes every acre you enter can be fenced, built on and connected, which on a real holding it cannot: hedgerows, rights of way, easements, flood zones, ponds and field corners all reduce the buildable area. Think of it as the question “if a developer wanted all of this, what is the order of magnitude?”, and then read the next section for the filters that decide whether that ever becomes an offer.

What the answer does not tell you

Grid connection comes first. A developer is buying the chance to connect a power station to the grid, and rent levels and interest follow grid capacity more than soil or acreage. Carter Jonas has said viable sites are generally within about 5km of a substation or have suitable overhead lines nearby. A big field two valleys from a substation with no spare capacity may attract nothing, while a smaller parcel next to one can attract several approaches.

Size matters, but there is no single minimum. Modern ground-mount schemes are large: Farmers Weekly reported in July 2024 that a 50MW scheme needs roughly 100 hectares, against 10 to 12 hectares for the 5MW farms of the 2010 boom. Carter Jonas has suggested 80 acres and above is viable, though some developers do take smaller parcels, particularly next to an existing connection.

Land quality changes the planning case, not the arithmetic. The National Planning Policy Framework defines best and most versatile (BMV) land as grades 1, 2 and 3a, and asks decision-makers to take land quality into account and to prefer poorer quality land where significant development of agricultural land is necessary. Councils must consult Natural England where a proposal not in line with the development plan would lead to the loss of 20 hectares or more of BMV land. The planning flag in the result above reflects that: it is a warning about burden of proof, not a ban. Defra published a Predictive ALC map for England in April 2026, but it is strategic (1:250,000) and not accurate enough to grade an individual field, so expect a field survey if a scheme goes ahead. Our land classification guide explains how to check your grade first.

Who decides depends on size. In England, schemes under 100MW go to the local planning authority; the national infrastructure threshold for solar rose from 50MW to 100MW on 31 December 2025. Scotland, Wales and Northern Ireland run their own regimes with different thresholds, so check with your council before relying on the English rules. Our guide to solar panels on farmland sets out the planning picture in full.

From an acreage to a lease: what happens next

If a developer is interested, the sequence is almost always the same: heads of terms, then an option agreement while the developer seeks planning permission and a grid offer, then a long lease once both are in hand. HCR Law describes option periods of three to five years, sometimes longer; Trowers & Hamlins describes anything from one to ten. During the option you typically receive an option fee, not the full rent, and you generally cannot talk to another developer. Lease terms commonly run 25 to 40 years, with index-linking, and revenue-share top-ups of around 4 to 6% of the scheme’s turnover have been quoted by Stephens Scown and Fisher German.

That is why the 25-year line in the result is labelled as it is: it multiplies the base rent by 25 with no indexation, no option-period discount and no risk that the scheme is never built. It is a sense of scale, not a forecast. Our solar farm land lease guide goes through each stage clause by clause, including decommissioning security, which is the point most landowners underestimate.

Tax can change the picture as much as the rent. Land let for solar normally loses Agricultural Property Relief from inheritance tax, and from 6 April 2026 100% APR and business property relief applies only to the first £2.5 million of combined qualifying property, with 50% relief above that. Rent is taxed as property income rather than farming profit. We are an independent publisher, not tax advisers: take advice from an agricultural tax specialist before you sign an option, not after.

Three ways to use the same land

A rent range is only one of three realistic routes. You can lease fields to a developer and take rent with no capital outlay. You can own a ground-mount array sized mainly to supply the farm, keeping the bill savings and export income but funding it and the grid connection yourself; our cost guide and savings calculator test those numbers. Or you can look at dual use, with sheep grazing under or around the panels, which our agrivoltaics guide separates into what is established and what is still only modelled. If grazing matters to you on a leased site, write the grazing rights and who pays for fencing and water into the heads of terms; it is far harder to add later.

Before you reply to a developer: a short checklist

• Take independent advice from a land agent and a solicitor before signing anything, including heads of terms, and ask who pays your professional fees.
• Find out your land grade and whether any field is BMV land before assuming the planning case is easy.
• Ask which substation the scheme would connect to and whether the developer already holds a connection offer.
• Ask for a firm longstop date on the option, a fee for each extension, and a plan that limits the option land so the whole farm is not tied up.
• Ask what security backs decommissioning, who can draw on it, and how often the amount is reviewed.
• Model the inheritance tax effect on the wider estate before, not after, you sign.

Sources

• DESNZ, land use per MW of existing and new ground-mount solar (872 sites; 2.25 ha median; 1.6 to 2 ha for new schemes), as cited on our farmland page.
• Arup for DESNZ, onshore wind and solar PV cost of electricity report (14 July 2025), developer survey of land and rental costs.
• Stephens Scown, solar farms: benefits for landlords (2023); Brown & Co (June 2024) and Fisher German (July 2024) as quoted in Farmers Weekly; Carter Jonas as quoted in Farmers Weekly.
• National Planning Policy Framework: definition of best and most versatile land; Natural England consultation threshold of 20 hectares of BMV land.
• Infrastructure Planning (Onshore Wind and Solar Generation) Order 2025 (solar NSIP threshold 100MW from 31 December 2025).