Solar carports turn a commercial car park into a generating asset
Solar carports are ground-mounted canopy structures built over the bays of a commercial or public car park, and they are the most overlooked solar surface in the country. A surface car park earns nothing per square metre, yet the same footprint can carry a solar canopy that generates power, shelters vehicles, and carries the structure and feed-in for the EV charging that retail, employer, healthcare and leisure sites must install anyway. The distinction that matters is this: a solar carport is not a roof array, it is a steel canopy engineered to stand over live parking, so the planning, structural and grid considerations differ from rooftop solar. A typical bay generates roughly 1,200 to 1,300 kWh each year, used on site at full retail rate while surplus feeds the chargers at generation cost.
How we size a solar carport
A solar carport sizes from the parking footprint, not from a roof. We plan around 1.5 to 2.0 kWp per standard bay (4 to 6 panels across roughly 12 square metres of canopy), so a 200 kWp system covers about 100 to 130 bays. At UK yields of around 850 to 1,000 kWh per kWp per year, a 100-bay car park generates roughly 120,000 to 130,000 kWh a year. We size for self-consumption first, then layer EV-charging demand on top. The steel structure is around 45% of total project cost, which is why per-kWp pricing falls as bay count rises and a 50-bay scheme is far better value than a 10-bay one.
Costs, payback and tax relief
Solar carports cost around £1,200 to £3,000 per kWp installed against £600 to £1,000 for rooftop, the difference being that fixed steel structure, and payback is typically 8 to 10 years. That is longer than rooftop, but the right comparison counts everything the carport returns. The biggest lever is tax: solar PV qualifies as plant and machinery, so the 100% Annual Investment Allowance lets most businesses write the PV plant off against profit in year one, worth up to a 25% effective tax saving for a limited company, with most single-site installs inside the £1m cap. The structural steel may be treated differently, so confirm the split with your accountant. Our cost guide works through the numbers by bay count.
Funding routes for solar carports and EV charging
Several routes stack on a solar carport. The Workplace Charging Scheme funds the EV-charging element: from 1 April 2026 it covers up to 75% of socket cost, capped at £500 per socket, for up to 40 sockets, claimed through an OZEV-authorised installer, to 31 March 2027. The Smart Export Guarantee pays for surplus generation at typically 4 to 15p per kWh as of 2026. Public-sector car parks (NHS, councils and universities) may access the Public Sector Decarbonisation Scheme via Salix. We are OZEV-authorised and prepare your Workplace Charging Scheme claim for you; the grants and funding page covers each route in detail.
Planning and structural considerations differ from rooftop
This is where carports part company with roof arrays. Since December 2023, Class OA of the General Permitted Development Order has removed full planning permission for most non-domestic, off-street car park canopies in England, replacing it with a prior-approval route: a 56-day determination on siting, design, glare and drainage. The conditions to watch are a 4m height limit, a 10m setback from any residential boundary, and the exclusions for listed buildings, scheduled monuments and conservation areas. Class OA does not currently extend to Wales or Northern Ireland.
Glare and drainage
Glare onto neighbouring premises, the public highway or any flight path is the most common prior-approval condition, so we run a glare and glint study (the methodology used near airports) and feed it into the submission. Because a canopy is a new impermeable surface over open tarmac, a SuDS drainage strategy is also required, and Class OA asks for it explicitly. The canopy is engineered to BS EN 1991 (Eurocode 1) wind and snow loading for a 25-year design life, the structural works fall under CDM 2015, and a G99 grid application is needed where inverter capacity exceeds 17 kW per phase. None of these apply to a rooftop retrofit in the same way.
How we approach the project
We start with your half-hourly meter data, because a solar carport only pays if it is sized to your load rather than to the car park. We confirm your planning route, submit the Class OA prior approval (or full planning where the site is excluded), and lodge the G99 grid application early because the DNO connection is usually the longest item in the programme. You then receive a fixed-price proposal, MCS commercial certification, and a phased build that keeps the car park open throughout.
An illustrative worked example
This example is illustrative only and depends entirely on your site, layout, load profile and tariff. A large out-of-town supermarket with a 160-bay car park, trading seven days a week with no roof space left after a rooftop install, fits a 240 kW canopy of around 530 panels over 130 bays, plus 20 EV charging sockets. The array generates roughly 216,000 kWh a year, around 75% self-consumed into store refrigeration and lighting, with a payback near 8.5 years. The Workplace Charging Scheme grant is claimed on the sockets, the PV plant is written off in year one under the Annual Investment Allowance, and prior approval is granted inside 56 days. Illustrative only.
See our pages on solar carports for retail car parks and solar carports for NHS and council car parks, browse the solar carport FAQs, or request a free feasibility.
