Ask three suppliers to price a commercial solar canopy and you will get three very different numbers, and none of them will look much like the £/kWp figure you were quoted for a roof. That is not sharp practice. A rooftop array borrows a structure that already exists. A canopy has to build one, sink it into the ground, and get it signed off to stand up under British wind and snow for the next thirty years. Knowing where that money actually goes is the difference between a budget that survives contact with a structural engineer and one that does not.
A canopy is a construction project with panels on top
The mental adjustment most property owners have to make is this: a large share of the capital cost of a solar canopy has nothing to do with solar. Panels, inverters and cabling are commodity items priced by a global market and they move very little between suppliers. Steel, foundations, groundworks, drainage, lighting, traffic management and surface reinstatement are construction items priced by your site. Two identical 200 kWp canopies on two different car parks can differ enormously in price purely because of what sits under the tarmac.
The steel: spans, geometry and finish
Structure is usually the single largest line item. Cost is driven by span (how many parking bays you clear between columns), by geometry (a single-sided cantilever, a back-to-back butterfly arrangement, or a full double-row canopy) and by finish. Long clear spans look better and protect your bay count, but they need heavier sections and bigger foundations, and the price curve steepens quickly as spans grow. Hot-dip galvanised steel is the baseline; a powder-coated topcoat for a customer-facing retail or hotel site costs more but is often non-negotiable for planning or brand reasons. Integrated guttering, downpipes and soffit lighting are commonly missing from early budget quotes and reappear at contract stage.
Foundations and groundworks: the variable that decides your budget
Below ground is where canopy budgets are won and lost. Piled foundations, mass concrete pads and screw piles all carry different costs, and which one you need depends on a ground investigation, not on a supplier’s standard detail. Made ground, contaminated fill, high water tables, shallow rock and buried services all push the number up. So does drainage: a canopy turns a permeable or free-draining car park into a large collecting surface, and planners increasingly want a sustainable drainage response to that. Then add surface reinstatement, re-lining, and phased working so the car park stays partly open during the build.
The practical advice is simple. Commission trial pits and a ground investigation before you accept a fixed price. A quote issued without one is an estimate with a provisional sum attached, and provisional sums only ever move in one direction.
Wind and snow loading: why every UK canopy is engineered individually
A solar canopy is a large, elevated, nearly flat surface on legs. Structurally, its defining problem is uplift, not weight. Wind gets under the deck and tries to lift it, which is why column sizes, baseplates and foundation depths are set by site-specific wind calculations reflecting exposure, altitude and local topography. Snow matters too, particularly drifting against an adjacent building. An exposed coastal or upland site will legitimately cost more per kWp than a sheltered urban one for identical panels. Be suspicious of any supplier quoting canopy structure from a catalogue without asking where the site is.
Grid connection: G98, G99 and the DNO timeline
Only very small systems, at or below 16A per phase, qualify for the connect-and-notify G98 route. Anything at canopy scale requires a G99 application to your Distribution Network Operator, submitted and resolved before you commit to the build. The DNO may accept the connection as proposed, may require an export limit, or may come back with network reinforcement costs that materially change the business case. Budget for both the connection charge and, just as importantly, the time: G99 determinations are measured in weeks to months, and they sit on the critical path in front of steel fabrication.
EV charging: the reason many canopies get built at all
Most commercial canopies are specified alongside EV charge points, and the two should be designed and dug as one job. Containment can be routed inside the steel, the charger supply can share the same trenching as the array cabling, and load management can be configured once across both. A car park excavated twice costs far more than a car park excavated once. Expect installed AC charge points in the low thousands of pounds per socket depending on containment runs and civils; DC rapid charging is a different order of cost and usually a separate grid conversation entirely.
How canopy costs compare with standard rooftop and domestic solar
The honest comparison is per kWp installed, excluding VAT, and treating every figure as indicative rather than a quote:
| System type | Indicative installed cost per kWp | Main cost driver |
|---|---|---|
| Commercial rooftop, 50–250 kWp | approx. £600–£900 | Equipment and labour; roof already exists |
| Ground-mount array | approx. £700–£1,100 | Frames, piling, land and cable runs |
| Solar canopy / carport | approx. £1,200–£2,000+ | Steel, foundations, groundworks, EV integration |
| Domestic rooftop, 4–6 kWp | approx. £1,200–£1,800 | Small-scale premium on fixed costs |
Domestic pricing is worth a glance for context, because it shows how the cost stack behaves when there is no structure to build. Published regional pricing for household roof-mounted systems, such as these solar panel costs in Cornwall, reflects jobs where almost the entire spend goes on panels, inverter, scaffolding and labour, with the roof supplied free by the building. Commercial rooftop then improves on that per kWp through sheer scale. A canopy reverses the trend, not because the solar is more expensive, but because you are buying a permanent steel structure and a set of foundations at the same time.
VAT, allowances and the revenue side
Commercial solar is standard-rated for VAT at 20%. The 0% rate that gets quoted so freely applies to domestic installations of energy-saving materials only, so do not let it appear in your appraisal; if your business is VAT registered the input tax is normally recoverable in the usual way. On capital allowances, the Annual Investment Allowance gives 100% relief on qualifying plant up to £1m, and for most single canopy projects that is the mechanism that matters. Where AIA is already used up, note that solar PV is special-rate plant: it attracts the 50% first-year allowance rather than 100% full expensing, with the balance going into the special rate pool. Confirm the treatment with your accountant before it appears in a board paper.
On the income side, self-consumption is the main event: every unit you generate and use is a unit you do not buy at commercial rates. Exported units earn a Smart Export Guarantee payment, but SEG tariffs vary between suppliers and should be treated as a secondary contributor, not the basis of the case.
Why the higher £/kWp can still be the better investment
Canopies earn their premium in three ways. They deliver dual land use, generating from ground you already own, pay rates on and cannot otherwise develop. The steel is a long-life asset with a design life comfortably beyond the panels, so re-powering later means swapping modules rather than rebuilding. And unlike a rooftop array, a canopy is unaffected by roof age, roof warranties and the disruption of a re-roof in year twelve, while adding sheltered parking, lighting and EV capacity that customers and staff can actually see. Higher cost per kWp, longer asset life, more jobs done at once. For the right site, that is a defensible trade.