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 paybacks often around 5.5 years for well-matched sites. 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 we model PV 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 we would always prove it on a trial area before committing a whole house to it.

What a typical install looks like and how we size it

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 21 to over 1,000 tonnes of CO2. 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 we model the PV as part of that whole-site picture rather than in isolation. Sizing comes 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. We look at where the firm, year-round demand sits and size 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, we look at whether ground-mount can make up the difference, and at 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 £90,000 to £4 million plus reflecting the breadth of the sector, with paybacks near 5.5 years for sites with strong daytime self-consumption. The 100% Annual Investment Allowance writes off qualifying plant against profit in year one within the annual cap, and larger schemes can be structured so relief is claimed efficiently across the capital where a single project exceeds the cap. 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 Annual Investment Allowance annual cap, in which case the relief on the balance is claimed through the normal capital allowances regime rather than all in year one. That still delivers full relief over time, and for a high-self-consumption site the avoided-import saving is large enough that the payback remains strong. For smaller nurseries the whole cost usually falls within the cap and is expensed in the first year. As always we present 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. We have seen on-site generation form part of the audited evidence that helps growers hold their place in a competitive supply chain.

Funding routes in detail

The 100% Annual Investment Allowance is the headline relief for owned horticultural systems, fully expensing qualifying plant in the first year up to the annual cap, with larger multi-megawatt schemes structured to claim relief efficiently across the capital. The Smart Export Guarantee provides ongoing income on exported units for MCS-certified systems up to 5 MW, paying in the region of 4 to 15p per kWh. The Sustainable Farming Incentive does not reward standalone glasshouse PV, but agrivoltaic glazing above crops can align with biodiversity and integrated management actions as that approach develops, and the scheme is moving towards clearer renewable alignment. The Farming Investment Fund occasionally helps where solar is paired with an eligible productivity item. Welsh and Scottish growers should examine their devolved schemes, the Welsh Rural Investment Scheme and the Scottish Rural Development Programme, which carry their own renewable support and frequently higher intervention rates than the England equivalents, a point well worth pursuing for capital-heavy horticultural projects.

Compliance and sector considerations

Standard rooftop PV on packhouses and stores follows the usual agricultural permitted development rules within size limits, while large ground-mount or glass-integrated schemes need full planning permission, with an Environmental Impact Assessment above 5 MW. A G99 grid application is needed above 17 kW per 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 we recommend an agronomic trial before any full deployment so you can see the effect on yield for your specific crop before committing the whole site. As across agriculture, older buildings may carry asbestos cement roofing under the Control of Asbestos Regulations 2012 that cannot take panels and needs replacing first, and tenanted sites need landlord consent for the works. We confirm all of this before issuing a price.

How we approach this kind of project

Horticulture is the segment where whole-site modelling matters most, so we start by pulling your half-hourly data and mapping the PV against your existing heat and refrigeration plant rather than treating it as a standalone purchase. We survey the packhouse and storage roofs, check for asbestos and confirm the structure before issuing a fixed-price proposal. Because these systems are large, we submit the G99 grid application early, alongside the survey, and run the connection study before final sizing so the design fits the available capacity rather than being trimmed back later. Where agrivoltaic glazing is under consideration we recommend a trial area first and bring in agronomic input rather than scaling an unproven approach across the whole crop, because protecting yield comes before protecting generation. Every install carries an insurance-backed workmanship warranty, and we phase the work to keep the nursery and packhouse operating throughout.

An illustrative example

As an illustrative composite based on typical UK horticulture projects, and not a real named client or real project, a glasshouse nursery with high supplementary lighting and packhouse cold storage installs 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 covers a meaningful share of daytime demand, with relief claimed under the Annual Investment Allowance and a payback in the region of 5 to 6 years. The figures are illustrative and depend on your crop, glazing, lighting regime and tariff; we model your own site before anything is committed, and we would never present a worked example 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 feasibility or read the agricultural solar FAQs.