Solar Car Parks: 2026 Cost & Payback Guide

A solar carport is not a roof array. It is a ground-mounted steel canopy built over the bays of a commercial or public car park, engineered to stand over live parking while it generates electricity and shelters the vehicles beneath it. That single structural difference is the reason solar carports cost more per kilowatt than rooftop solar, and it is the first thing any facilities or estates manager needs to understand before reading a quote. This guide sets out 2026 pricing honestly: what you pay, why the canopy carries a premium, and how the payback actually works once EV charging and tax relief are in the picture.

What a solar carport costs per kWp in 2026

Solar carports typically cost around £1,200 to £3,000 per kWp installed (ex-VAT). Rooftop commercial solar, by comparison, runs around £600 to £1,000 per kWp. The gap is large and it is structural, not a margin grab.

The reason is the steel. On a rooftop install the roof already exists, so the project pays for panels, inverters, mounting rails, cabling and labour. A solar carport has to build the surface the panels sit on first: foundations, columns, beams, purlins and the canopy frame, all engineered to carry wind and snow load over occupied bays. That steel structure accounts for roughly 45% of total project cost. You are paying for a building, then putting solar on it.

That 45% is also why per-kWp pricing falls sharply as a scheme gets bigger. The structural overhead is broadly fixed per bay, so a 50-bay scheme spreads that cost across far more generating capacity than a 10-bay scheme. Carports become genuinely cost-effective at scale, and the sites that see the strongest numbers are surface car parks of 50 bays and up.

Illustrative project sizes

The figures below are illustrative only and depend entirely on your site, layout, ground conditions and the canopy design chosen. They are guide ranges, not quotes.

• A 100-bay scheme of roughly 150 to 200 kWp typically runs around £180,000 to £350,000.
• A 200-bay scheme of roughly 300 kWp typically runs around £290,000 to £345,000 as the per-kWp rate drops with scale.
• A larger 350-bay healthcare or retail car park of 600 kWp can reach £1 million-plus, but at a materially lower cost per kWp than a small workplace canopy.

Notice how the cost per kWp keeps falling as bay count rises. That is the steel-at-scale effect in action, and it is the single most important number to model before committing to a size.

How much a solar carport generates

Solar carports size from the parking footprint, not from a building roof. Plan around 1.5 to 2.0 kWp per standard bay, which is roughly four to six panels across about 12 square metres of canopy per bay. At UK yields of around 850 to 1,000 kWh per kWp per year, each bay generates roughly 1,200 to 1,300 kWh annually.

So a 100-bay car park generates somewhere around 120,000 to 130,000 kWh a year. A 200 kWp system covers about 100 to 130 bays. That is enough to take a real bite out of a site’s grid bill and to feed a bank of EV chargers without drawing everything from the network at full retail rate.

Why payback is longer than rooftop, and why that is the wrong number

Be ready for this: a solar carport pays back in roughly 8 to 10 years on the panels alone, against 5 to 7 years for rooftop. The steel is the reason, and any honest installer will say so up front.

But the panel-only payback is the wrong figure to judge a carport on, because the canopy returns value a roof never can. There are four levers that the rooftop comparison ignores.

1. The 100% Annual Investment Allowance

Classed as plant and machinery, the PV plant can be set against the year’s taxable profit under the 100% Annual Investment Allowance, handing a limited company up to a 25% effective tax saving. With the AIA applying to the first £1m of qualifying expenditure each year, a single-site carport install almost always sits within the limit. One important caveat: the structural steel canopy may be treated differently from the PV plant for capital allowances, so confirm the split with your accountant. See the government’s capital allowances guidance for the current rules.

2. EV-charging value

A carport carries the structure, cable routes and a behind-the-meter solar supply for EV chargepoints you very likely have to install anyway. Behind-the-meter solar feeds those chargers at your generation cost rather than full grid retail, which improves the margin on paid public charging and cuts the cost of free staff or fleet charging.

3. The Workplace Charging Scheme grant

The EV sockets themselves can be part-funded. The Workplace Charging Scheme can cover part of the socket purchase and installation cost, claimed through an OZEV-authorised installer (see gov.uk for the current contribution rate, per-socket cap and end date).

4. Smart Export Guarantee income

Surplus generation, the power you do not use on site, earns income under the Smart Export Guarantee at typically 4 to 15p per kWh as of 2026, depending on the supplier you choose. This matters most at sites with little out-of-hours load, such as weekday-only offices or weekend-only attractions.

Model those four together and the blended return is considerably stronger than the panel-only payback suggests. The right question is not “how long do the panels take to pay back?” but “what is the blended IRR once savings, charging value, the grant and tax relief are all counted?”

Self-consumption is the biggest single driver

The economics of any solar carport live or die on self-consumption: how much of the generation you use on site at full retail rate, rather than exporting it cheaply. Every kWh consumed on site is worth your grid import price; every kWh exported is worth the SEG rate, which is far lower.

This is why sites with strong daytime demand do best. A supermarket running refrigeration and lighting through trading hours, an NHS site with 24/7 baseload, or an office at full weekday occupancy will self-consume most of what the canopy makes. A good installer will model your half-hourly meter data, size the array to your load first, layer EV charging on top, and only then treat the surplus as export. Sizing to the car park instead of to the load is the most common and most expensive mistake.

Running costs

Budget for annual operations and maintenance: electrical inspection, inverter checks, occasional panel cleaning, plus periodic structural inspection of the steel, fixings and gutters. Typical O&M is around £8 to £12 per kW per year for systems above 250 kW. Cleaning is usually easier than rooftop because the canopy sits at low level and is accessible. The steel is galvanised or coated for a 25-year-plus design life that matches the PV warranty.

Work the numbers for your own site

Headline ranges only take you so far. The cost and payback of a solar carport turn on your bay count, your daytime load, your tariff and whether you are adding EV charging. Try our savings calculator for a first-pass estimate, read the full cost breakdown by bay count, check which grants and funding you can stack, or look at the numbers for retail and supermarket car parks specifically. When you are ready for a site-specific figure rather than a range, request a free feasibility.