Is a commercial solar carport worth it?
Short answer: often, but not always. A commercial solar carport is worth building when your roof is already full or structurally unsuitable, when a genuine share of your electricity is used on site during daylight, and when you need EV charging that the canopy can feed directly. In that situation payback on the solar alone typically runs to about eight to ten years, and it shortens once EV charging revenue and the capital allowances are factored in.
It is usually not worth it when bays are few and heavily shaded, when the site has almost no daytime electrical load, when a short lease leaves no time to recover the steelwork, or when the grid connection is weak. In those cases a rooftop array or a power-purchase agreement (PPA) is the better first move. The honest test is whether the structure earns its keep, because a carport canopy costs roughly two to three times as much per kWp as the same panels bolted to an existing roof. This page walks the real numbers rather than the sales-brochure ones.
Where the return actually comes from
A carport stacks several returns that a bare rooftop array does not. Each one is real, and each one carries a caveat. Treat the table below as the checklist you would run before committing capital.
| Return | What it delivers | Honest caveat |
|---|---|---|
| Bill savings (self-consumption) | Every kWh you generate and use on site displaces grid electricity at your full import rate. This is where most of the value sits. | Only worthwhile if you draw power during daylight. A site that runs at night gains far less. |
| EV charging | The canopy shades the cars and powers the chargers beneath it, avoiding a separate steel run and turning parking into a chargeable service. | Grid capacity and charger dwell times decide the yield. Model it before assuming revenue. |
| Workplace Charging Scheme (WCS) | Up to £500 per socket, capped at 75% of cost, up to 40 sockets, and £2,000 per socket for state-funded education, running to 31 March 2027. | It funds chargers, not the carport. The staff-and-fleets and landlord grants closed on 31 March 2026. |
| Capital allowances | Solar PV is special-rate plant, so companies can claim the 100% Annual Investment Allowance (up to £1m) and, where AIA is used up, a permanent 50% first-year allowance. | It is not full expensing and not the 40% main-rate allowance. Take your own tax advice. |
| Business-rates exemption | Eligible solar generation is exempt from business rates in England until 31 March 2035. | England only. Wales and Scotland are not covered by this exemption. |
| Sheltered, branded asset | Covered parking is a visible sustainability statement, protects vehicles and stock, and can be branded for staff and customers. | Genuine but soft. Do not let it carry a business case the hard numbers cannot. |
What a carport realistically costs and generates
At commercial scale a solar carport lands at roughly £1,100 to £1,600 per kWp, rising to £1,200 to £3,000 per kWp on smaller schemes, or about £6,000 to £12,000 per parking space excluding VAT. The steel structure is the reason: it accounts for something like 40 to 50% of the total, which is why a carport is two to three times the cost of a £700 to £1,050 per kWp rooftop array. Because you are a business you pay 20% VAT, but it is recoverable, so we quote ex VAT. The 0% residential rate does not apply here; a standalone carport is not expressly covered by HMRC, so confirm the position per project. Our full breakdown sits on the cost page.
On the generation side, UK yield sits around 900 to 950 kWh per kWp a year. A typical bay carries about 2 kWp, so each bay produces roughly 1,700 to 2,000 kWh annually. As an illustrative scenario only, a 50-bay canopy at 2 kWp per bay is around 100 kWp and would generate in the region of 90,000 to 95,000 kWh a year. Above 3.68 kW per phase you connect under G99 rather than G98, which most commercial schemes trigger, and that application commonly takes eight to sixteen weeks. Details of the physical build are on how solar carports are installed.
The objections worth pressing on
The payback is longer than a rooftop array, so why bother?
Because the comparison is rarely like-for-like. A carport is the answer when there is no suitable roof, or when the roof is spoken for and you still have parking generating nothing. You are also buying EV infrastructure and covered parking at the same time. Judge the carport against doing nothing on that land, not against a rooftop you cannot use.
A supplier quoted us a four to five year payback. Is that credible?
For a solar-only carport, treat that with caution. Steel roughly doubles or triples the cost per kWp versus rooftop, so a four-year payback usually assumes very high self-consumption, an inflated export price, or both. A defensible solar-only payback is about eight to ten years, pulled shorter by EV charging revenue and the capital allowances. If a number looks too good, ask which import rate, export rate and self-consumption figure produced it.
What will we actually earn on exported power?
Less than the brochures imply. The Smart Export Guarantee is supplier-set and variable, not a flat 15p. Octopus Outgoing sits at 12p (down from a historic 15p, cut on 1 March 2026), a standalone meter can be as low as 4.1p, and only some variable tariffs reach the 25 to 30p range under specific conditions. For commercial volumes, export is usually handled through a PPA. The business case should lean on self-consumption, not export.
Will planning kill the project?
Rarely, and it is a standing right, so there is no reason to rush. In England, Class OA (in force since 21 December 2023) gives prior approval rather than full planning, assessing siting, design and glare, with a 56-day determination. SuDS run-off is a mandatory condition, not a prior-approval matter. Canopies must be up to 4 metres tall, more than 10 metres from a dwelling, must not be on listed or scheduled sites, carry no adverts, and must be completed within three years. In Scotland, Class 9M (in force 24 May 2024) makes the canopy permitted development outright. Wales and Northern Ireland generally need full planning, decided case by case.
When a solar carport is not worth it
This is the part most sales pages skip. A carport is the wrong call, or at least the wrong first move, in these situations:
- North-heavy orientation or serious shading. Buildings, mature trees or a slope that keeps the canopy in shade wreck the yield the whole business case depends on.
- Tiny bay counts. Cost per kWp is worst on the smallest schemes, so a handful of bays rarely justifies the steel. Look at rooftop or a ground mount instead.
- No daytime load. If the site is empty during generating hours and export is poor, you are effectively selling power at 4 to 12p to buy it back later. The maths does not work.
- Short lease with no PPA. If you cannot recover the structure within the lease and the landlord will not agree a PPA or an asset transfer, do not fund the steel.
- Weak DNO capacity. If the connection cannot take the array plus chargers without an expensive reinforcement, the upgrade can swallow the return. Confirm capacity before design.
In several of these cases the right answer is to do rooftop first, or to take a PPA where a third party funds and owns the system and you buy the power. Neither is a failure; both protect your capital.
Carport vs rooftop vs doing nothing
| Solar carport | Rooftop solar | Do nothing | |
|---|---|---|---|
| Capital per kWp (ex VAT) | ~£1,100–£1,600 at scale | ~£700–£1,050 | £0 upfront |
| Solar-only payback | ~8–10 years | Shorter; no structure to fund | None; bills keep rising |
| Where it wins | Roof full or unsuitable; parking with daytime load and EV demand | Sound, unshaded roof with spare capacity | No spare capital and no daytime load at all |
| EV charging | Integrated under the canopy; WCS-eligible chargers | Separate groundworks and cabling needed | Grid-only charging at full import cost |
| Planning | Prior approval (England Class OA); permitted in Scotland (Class 9M) | Usually permitted development on existing roofs | Not applicable |
| Main risk | Steel cost, shading, DNO capacity | Roof age and load capacity | Exposure to import prices and, potentially, tightening EPC rules |
On MEES, the non-domestic minimum is currently EPC E. A proposed tightening to C by 2027 and B by 2030 is exactly that, a proposal, not law, so we will not price a decision on rules that do not yet exist.
How to decide, in order
- Confirm daytime load. Pull half-hourly meter data and check how much power you use while the sun is up.
- Check the roof first. If there is a sound, unshaded roof going spare, cost that before the carport.
- Test the grid. Ask the DNO what the connection can take with the array and chargers combined.
- Model both routes. Compare an owned carport against a PPA using your real import rate, not a headline number.
- Layer the incentives. Fold in the WCS grant, the capital allowances and the England business-rates exemption where they apply, with your accountant.
Run those five steps and the answer to whether a commercial solar carport is worth it stops being a guess. When you want the numbers modelled against your own site, ask for a feasibility quote and we will tell you honestly if rooftop or a PPA is the smarter first move.