Glasshouse / Horticulture: Solar panels for agriculture

Glasshouses and horticulture: the most energy-intensive corner of agriculture

Protected horticulture is among the most energy-hungry forms of agriculture in the country, and that is precisely why solar panels for agriculture make such a strong case here. Glasshouse heating, supplementary lighting, irrigation pumps, packing lines and cold storage add up to a large, steady electricity demand that runs for much of the year, and that demand is exactly what solar rewards. Vertical farming sites are even more pronounced, with lighting loads that dwarf most other forms of farming. Where the load is high and constant, a large PV system is consumed on site rather than exported, and self-consumption drives a strong return, with an indicative simple payback of roughly 4 to 7 years where most of the output displaces imported power at 24p to 28p per kWh. For a grower running on tight energy margins, fixing a slice of that cost for two decades is a meaningful structural improvement to the business, not a marginal saving.

Horticulture also tends to supply retailers directly, so the Scope 2 reduction that solar delivers feeds straight into buyer sustainability requirements and supply-chain disclosures. For a grower competing on both price and environmental credentials, on-site generation is a genuine commercial asset rather than just a saving. Within the wider agricultural energy picture, horticulture is the segment where solar most often forms one part of a whole-site strategy alongside other plant, because the heating and lighting loads are large enough that no single technology covers them on its own. That is why PV should be modelled in the context of your existing heat source rather than as a stand-alone purchase, and why the right answer for a glasshouse is usually a combination rather than a single product.

Vertical farming deserves a particular mention, because it is an exceptionally good fit for solar. These sites run lighting loads that dwarf most other forms of farming, with demand that is high, steady and almost entirely indoors, so a large array is comfortably absorbed and self-consumption is excellent. Where the building footprint allows, the roof and surrounding land can carry enough PV to meet a meaningful share of that lighting demand directly. At the other emerging edge of the sector, agrivoltaic glazing, meaning translucent panels mounted above the crop itself, is starting to appear in protected horticulture, though it remains early and it is sensible to prove it on a trial area before committing a whole house to it.

What a typical system looks like and how it should be sized

Horticulture systems span a very wide range, from around 100 kW to 5 MW, roughly 185 to 9,200 plus panels, generating from about 92,000 kWh to 4.6 million kWh plus a year and saving from 12 to over 600 tonnes of CO2e (at the 2026 DESNZ grid factor of 0.131 kg CO2e per kWh). Panels usually sit on packhouse and storage roofs rather than the glass itself, though agrivoltaic glazing above crops is emerging. Because heating and lighting loads can be enormous, solar is frequently one element of a wider energy strategy that also includes combined heat and power or heat pumps, and a good installer will model the PV as part of that whole-site picture rather than in isolation. Sizing should come from your half-hourly data and the realistic roof area on the packhouse and stores once rooflights and shading are allowed for, matched to the very high daytime baseload that lighting and refrigeration create.

The breadth of the sector means there is no single template. A salad or soft-fruit nursery with heavy supplementary lighting runs a very different load profile to a cold-storage and packing operation, and a vertical farm runs different again, with lighting demand so high that a large array is comfortably absorbed. A good installer looks at where the firm, year-round demand sits and sizes the PV to that, because exporting surplus at the lower rate is poor value when the same units could be displacing expensive imported power for lighting or cooling. Where the roof area on the packhouse and stores is limited relative to demand, ask whether ground-mount can make up the difference, and how storage might help shift midday generation into evening lighting runs.

Solar rarely stands alone in horticulture. Glasshouse heating in particular is usually met by a combination of plant, so PV is most powerful when it is designed as one element of a wider energy strategy that may also include combined heat and power or heat pumps. CHP and heat pumps shift how and when the site draws electricity, which in turn changes the ideal solar size, so modelling them together rather than in isolation avoids both over-sizing the array and under-using the generation. For a grower already running or considering heat plant, that integrated view is the difference between a system that simply offsets a slice of the bill and one that is properly matched to how the whole site uses energy across the year.

Costs, payback and tax relief

Projects range from around £75,000 to £105,000 for a 100 kW roof (indicative, from installer and industry price guides, ex VAT, excluding grid reinforcement, re-roofing and batteries; there is no official cost series above 50 kW) up to several million pounds for the largest multi-megawatt sites, with an indicative payback of roughly 4 to 7 years for sites with strong daytime self-consumption. The 100% Annual Investment Allowance gives 100% relief on qualifying plant against profit in year one up to £1m a year; above that, companies can claim the 50% special-rate first-year allowance, with the balance going into the 6% special-rate pool. The Smart Export Guarantee covers any surplus export, though high-baseload glasshouse sites tend to consume most of what they generate. Our cost guide works through the economics at glasshouse scale and the funding page covers the relief in detail.

At the larger end of horticulture, a single project can exceed the £1m Annual Investment Allowance cap. Above the cap, companies can claim the 50% special-rate first-year allowance and the remainder is written down in the 6% special-rate pool, so relief on the balance is spread over many years. For a high-self-consumption site the avoided-import saving is often large enough that the payback remains strong. For smaller nurseries the whole cost usually falls within the cap and is relieved in full in year one under the AIA. This guide gives a range rather than a single figure, because crop, glazing, lighting regime, the existing heat source and tariff all move the number, sometimes substantially.

There is a commercial dimension beyond the bill, too. Horticulture supplies the major retailers directly, and those buyers increasingly ask their suppliers to evidence reduced Scope 2 emissions through supply-chain disclosures. A live solar array is exactly that evidence: auditable, on-site generation that demonstrably displaces grid power. For a grower competing on price as well as environmental credentials, that can support a contract conversation rather than just trim the energy line, and it positions the business well as retailer requirements tighten. On-site generation can form part of the audited evidence that helps a grower hold its place in a competitive supply chain.

Funding routes in detail

The 100% Annual Investment Allowance is the headline relief for owned horticultural systems, relieving qualifying plant in full in year one up to £1m a year; above that, companies can claim the 50% special-rate first-year allowance, with the balance in the 6% special-rate pool. Solar does not qualify for full expensing. The Smart Export Guarantee pays for exported units on systems up to 5 MW, with export rates for businesses varying roughly from 3p to 15p per kWh; MCS certification is required for systems up to 50 kW, while larger systems use Ofgem ROO-FIT accreditation. The Sustainable Farming Incentive does not pay for solar panels (it reopened as SFI26 in 2026, paying for land-management actions only); land under panels can sometimes sit alongside separate environmental actions, subject to scheme rules, so check with the RPA. No farm solar capital grant is open in England in 2026: Improving Farm Productivity round 2 closed at the end of July 2025 and FETF 2026 did not fund solar. Growers in Wales, Scotland and Northern Ireland should check current devolved schemes, none of which pays for solar panels at the time of writing, so plan capital-heavy horticultural projects on tax relief and avoided import rather than grant funding.

Compliance and sector considerations

Rooftop PV on packhouses and stores is normally permitted development under GPDO Part 14 Class J in England, with no capacity cap, though systems over 50 kW need prior approval from the local planning authority on design and glare, and listed buildings are excluded. Ground-mounted or glass-integrated schemes should be treated as needing full planning permission, and larger ground-mount schemes may need EIA screening by the planning authority. A G99 grid application is needed for anything above 16 A per phase (about 11 kW three-phase), and on a capacity-constrained rural network the connection study should come early because horticultural systems are often large. Agrivoltaics, meaning translucent panels above crops, is an emerging option, and an agronomic trial before any full deployment lets you see the effect on yield for your specific crop before committing the whole site. Older buildings may carry asbestos cement roofing, which panels should not be fixed to; it usually needs replacing first by trained contractors following HSE guidance under the Control of Asbestos Regulations 2012, and tenanted sites need landlord consent for the works. A good installer should confirm all of this before issuing a price.

What a good installer should do on this kind of project

Horticulture is the segment where whole-site modelling matters most, so ask the installer to start from your half-hourly data and map the PV against your existing heat and refrigeration plant rather than treating it as a standalone purchase. A good installer will survey the packhouse and storage roofs, check for asbestos and confirm the structure before quoting. Because these systems are large, the G99 grid application should go in early, alongside the survey, with the connection study run before final sizing so the design fits the available capacity rather than being trimmed back later. Where agrivoltaic glazing is under consideration, a trial area with agronomic input is wiser than scaling an unproven approach across the whole crop, because protecting yield comes before protecting generation. Ask what workmanship warranty the installer offers and whether it is insurance-backed, check their MCS certificate on the MCS register, and agree how the work will be phased to keep the nursery and packhouse operating throughout. To get started, send the enquiry form and SEO Dons passes it to an installer covering your area.

An illustrative example

As an illustrative example based on typical UK horticulture figures, not a real farm or project, a glasshouse nursery with high supplementary lighting and packhouse cold storage might install around 400 kW across its packing and storage roofs, generating roughly 380,000 kWh a year and consuming most of it on site against a large baseload. Paired with existing heat plant, the PV would cover a meaningful share of daytime demand, with relief claimed under the Annual Investment Allowance and an indicative simple payback of roughly 4 to 7 years if most output displaces imports at 24p to 28p per kWh. The figures are illustrative and depend on your crop, glazing, lighting regime and tariff; an installer should model your own site before anything is committed, and no worked example should be read as a guaranteed outcome for a different nursery.

If you also farm arable land or are weighing dual land use, see arable solar and agrivoltaics in the UK. To understand the economics at scale, read the cost guide and the grants and funding page, then request a free quote or read the agricultural solar FAQs.