Solar Carports UK: Turning Car Parks into Power Assets

Car parks are one of the UK's most under-used solar assets. Acres of tarmac sit open to the sky while businesses pay rising electricity bills just metres away. A solar carport — a steel canopy structure with solar panels forming its roof — changes that equation, generating clean power directly above the vehicles it shelters. Supermarkets, councils, hotel chains and business parks are all adopting the format, and a 2025 government call for evidence signalled that mandating solar canopies on new commercial car parks may follow.

What is a solar carport?

A solar carport is a freestanding canopy structure — not attached to a building — where solar panels form the roof above parking spaces. Unlike rooftop solar, which uses an existing roof surface, a carport creates its own structure: steel columns rise from the tarmac, support a frame of purlins and rafters, and solar panels are mounted flush on top. Vehicles park underneath, gaining weather protection; the panels generate electricity that feeds the site's distribution board, an on-site battery or an EV charging station.

The format suits any large flat car park: supermarkets, retail parks, hotels, NHS trusts, councils, universities and manufacturing facilities. The Bentley Motors plant in Crewe, for example, operates a 2.7 MW carport array with 10,000 panels — one of the largest in the UK.

How much does a solar carport cost in the UK?

Costs vary considerably with system size, structural specification and groundworks, but a useful planning figure for commercial projects is roughly £2,000–£5,000 per parking space, all-in. The Department for Energy Security and Net Zero (DESNZ) estimated in its May 2025 call for evidence that an 80-space car park installation costs approximately £140,000 at 2025 prices — around £1,750 per space for a no-frills implementation — though bespoke architectural canopies, branded columns or complex groundworks push costs higher.

The steel structure (columns, purlins, canopy frame) accounts for roughly 45% of total project cost — the main reason solar carports cost two to three times more per kWp than equivalent rooftop installations. There is no existing roof to leverage; the structure must be engineered from scratch. Panel costs, cabling, switchgear and grid connection make up the remainder.

For a typical 80-space commercial installation, DESNZ modelled annual revenues of approximately £22,000 per year if all electricity is exported via the Smart Export Guarantee — or substantially more if consumed on-site to displace grid electricity at current commercial rates. That implies a simple payback of six to eight years before applying tax reliefs.

Planning rules: Class OA permitted development

In December 2023 the UK government introduced Class OA under Part 14 of the Town and Country Planning (General Permitted Development) (England) Order 2015, specifically to enable solar canopies above non-domestic off-street car parks without full planning permission. Under Class OA you can install, alter or replace a solar canopy on commercial off-street parking, subject to prior approval from the local planning authority (LPA).

The key limits to stay within Class OA are:

• The canopy must not exceed 4 metres in height.
• No part of the structure may be within 10 metres of the curtilage of a dwellinghouse or block of flats.
• The site must not be a listed building, scheduled monument or within Article 2(3) land (conservation areas, National Parks, AONBs, World Heritage Sites).
• Prior approval is required for siting, design, external appearance and any glare impact on neighbouring occupiers.
• If the canopy is above a permeable surface, run-off must be directed to a permeable or porous area within the car park.

Most business park, supermarket and industrial estate car parks in England therefore qualify for the streamlined prior-approval route. Wales has no equivalent class; projects there still require a full planning application. Scotland has its own framework — check with the local authority. For listed settings, sites near residential boundaries or elevated structures, a full planning application remains appropriate.

Why bifacial panels suit carports especially well

Bifacial solar panels generate electricity from both their front and rear surfaces, and car parks provide near-ideal conditions to exploit this. Light-coloured concrete or pale tarmac beneath the canopy reflects diffuse and direct sunlight back up onto the rear of the panels — a phenomenon known as albedo gain. Research published in the journal Clean Energy found bifacial systems in UK installations achieved a 15–17% power gain over equivalent monofacial panels, particularly under the diffuse light conditions common in the UK climate.

For a standard rooftop installation, bifacial panels offer limited advantage because the rear face sits close to dark roof tiles. For a carport — elevated several metres above a reflective surface, with clear air beneath — the albedo gain is much larger. Contractors typically specify bifacial panels as standard for carport projects, accepting the modest premium for improved energy yield over the system's 25-year life.

EV charging integration

Combining solar generation with EV charging creates the most compelling commercial case for a carport. Panels generate electricity throughout the working day; chargers consume it directly, cutting grid purchases. A battery bridges peak generation (midday) and peak charging demand (morning arrivals and lunchtime). The government's 2025 call for evidence explicitly cited this pairing as a primary policy driver, noting it reduces grid reinforcement costs compared to adding EV chargers on grid power alone. Vehicle-to-grid (V2G) technology — bi-directional power flow from EV batteries back to the building — is an emerging complement being trialled by several UK councils and fleet operators.

For guidance on charger hardware, see our best EV charger UK guide. Businesses planning a wider solar installation alongside a carport should read our commercial solar panels UK guide on system sizing, grid connection and tax treatment.

Structural requirements

A solar carport is a freestanding steel structure that must be engineered to Eurocode standards. BS EN 1991-1-4 governs wind loading; BS EN 1991-1-3 covers snow loads, which range from around 0.3 kN/m² in lowland southern England to over 1.0 kN/m² in the Scottish Highlands. Coastal and exposed upland sites require heavier column sections and deeper foundation piles. The car park sub-base must be assessed for bearing capacity — older tarmac may need remediation before columns can be installed. A structural engineer's sign-off is mandatory and forms part of the prior-approval submission under Class OA.

VAT and tax treatment for businesses

Commercial solar carports attract 20% VAT, which VAT-registered businesses reclaim in full on their next quarterly return. HMRC treats solar panels as plant and machinery, making the installation eligible for the Annual Investment Allowance at 100% in the year of purchase (up to the £1 million AIA limit) — a significant corporation tax saving in year one. Plant and machinery generating electricity primarily for on-site consumption does not automatically attract a separate business rates entry, but larger export-focused arrays may be assessed differently; take independent advice before signing contracts.

Typical system sizes and output

Each parking space accommodates roughly two to four 400–450 W panels, yielding around 1–2 kWp of installed capacity per space. An 80-space car park therefore supports an 80–160 kWp system. At the UK average irradiance of approximately 1,000–1,100 kWh/kWp/year, that translates to 80,000–176,000 kWh of annual generation — enough to cover a substantial share of a medium-sized office or retail building's electricity use. Adding a commercial battery of 50–100 kWh shifts generation into evening peak hours and reduces reliance on costly grid tariff periods.

Key takeaways

• Solar carports generate electricity from existing car park space — no extra land needed.
• Class OA (England) reduces planning to a prior-approval process for most commercial sites.
• DESNZ costed an 80-space installation at around £140,000, with payback of six to eight years before tax reliefs.
• Bifacial panels yield 15–17% more energy than monofacial equivalents in carport applications.
• Combining solar with EV chargers is the primary commercial driver and reduces grid reinforcement needs.
• VAT recovery plus 100% AIA in year one significantly reduce the net cost for UK businesses.