Should your business choose solar carports or rooftop solar?

Compare your usable roof with your usable parking area, then price complete designs against the same electricity demand. England's solar canopy route introduced a 4 metre height limit alongside other conditions [S3]. A carport adds a structure and foundations; rooftop solar needs a suitable roof. Confirm the consent route and site-specific engineering before choosing. Checked October 2026.

Last checked 16 October 2026

What is a solar carport, and how does it compare with rooftop solar?

A solar carport combines a parking canopy with solar PV, meaning photovoltaic generation. Rooftop solar uses your building’s roof as the installation location. Both need a design that turns sunlight into usable electricity, but their civil and structural work differs. BRE provides separate technical guides for roofs and solar car parks. Use them for design questions, rather than historic prices or current planning conclusions. [S1] [S2]

Start by writing down why you want the project. Electricity for daytime operations, weather cover and charging provision are separate objectives. Give each objective a place in your tender. Avoid attributing a cash value to customer comfort or extra visits unless you have evidence and a method for doing so.

This is a tender checklist based on the different scopes in BRE’s guides. It does not rank either option for your site. [S1] [S2]

Which option fits your commercial building and car park?

Request a roof-condition survey before assuming the roof is the simpler project. Ask whether panels will need to come off for planned repairs. Include rooflights, plant and safe access in the usable-area drawing. For a flat roof, read flat roof solar before commissioning the layout.

For the carport, request a utilities survey, foundation design and vehicle movement plan. BRE’s carport guide identifies structure, foundations, drainage and user interaction as design matters. Ask how the proposed layout handles delivery vehicles, accessible routes, emergency access and routine maintenance. [S2]

Mark temporary closures separately from permanent changes to parking. Request the number of spaces available during each construction phase and after completion. Have your site manager review turning movements and loading access before approving the canopy drawing. Do not accept a capacity total without a usable parking plan.

Which solar option produces more useful electricity?

Ask for output estimates using the same weather dataset and loss assumptions. A fair comparison shows installed capacity, annual generation, generation used on site and surplus export. Kilowatts, or kW, measure power; kilowatt-hours, or kWh, measure energy. Do not compare an annual energy figure with a power rating.

PVGIS can model location, orientation, slope and system losses. Request those inputs for each option and ask the designer to explain local shading. More panel capacity can give a larger annual total without matching your working-day demand. Compare the generation profiles with your consumption records. [S5]

Use solar self-consumption versus export to separate the value of electricity used in your building from electricity sold away from it. If charging is proposed, model charging demand separately rather than assuming every sunny period brings a paying driver.

Do solar carports need different planning permission from roof panels?

Yes, assess them as different proposals. The explanatory memorandum for England’s canopy permitted development route describes a maximum height of 4 metres and prior approval covering siting, design and appearance. It also describes exclusions, drainage conditions and removal obligations. Meeting the height limit alone is insufficient. Ask the council to confirm the current route for your drawings, and check legal interpretation with your solicitor. [S3]

That route concerns qualifying non-domestic off-street car parks at ground level. Do not assume it applies to a multi-storey car park, a roof extension or every existing canopy. Read solar carport planning before commissioning a consent package.

The cited route is for England. For Scotland, Wales or Northern Ireland, obtain the relevant authority’s position using that nation’s rules. The older BRE guides remain useful for technical questions, but their planning fees and connection terminology should not be used as current instructions.

How should you compare costs and funding offers?

Request complete prices with exclusions visible. For roofs, include preparation, access, mounting and potential future removal. For carports, include foundations, structural steel, drainage, traffic management and reinstatement. Ask each bidder to separate shared electrical works from option-specific work.

For fully funded, show any host rent separately from electricity purchase commitments. For part funded, identify your capital contribution, ownership rights and share of operating costs. For self funded, include maintenance and replacement allowances. Ask your accountant to review tax assumptions and your solicitor to review site rights and exit terms.

Your distribution network operator, or DNO, must assess the network connection. UK Power Networks provides commercial guidance covering solar, storage and combined technologies. Ask your own DNO about the proposed export and any network works. Sharing a site does not remove the need to review the complete electrical scheme. [S4]

What should you do next?

Prepare a roof survey, parking plan and consumption records. Request comparable designs with separately priced charging and storage options. Read solar carport costs, then get matched with an installer that covers your area.

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