How do commercial solar carports generate revenue?
Key takeaways A commercial solar carport generates revenue through four distinct streams: electricity cost savings, paid EV charging income, Smart Export Guarantee (SEG) payments, and year-one tax relief via the Annual Investment Allowance.
For a well-sited 50-bay carport, those four streams combined can reach £30,000-£50,000 in year one. The AIA alone returns up to 25p of every pound spent on the structure in year-one tax relief.
EV charging is the fastest-growing revenue stream and the one most businesses underestimate at initial appraisal stage. The carport structure costs more per kWp than a rooftop system, so understanding all four revenue streams is critical. |
Most businesses that enquire about solar carports are thinking about one thing: electricity savings. That is the right place to start, but it's not the full picture. A commercial solar carport generates revenue in four distinct ways and the businesses that make the strongest financial case for building one understand this.
The financial justification matters because carports cost more per kWp than rooftop installations. The steel or aluminium canopy structure is a real additional expense. If you are only counting electricity savings the numbers are less compelling than a straightforward rooftop system of the same generating capacity. However, when you consider all four revenue streams, then the picture changes substantially.
It’s also worth noting that each site is different. Not all rooftop commercial operations might be suited to a solar installation, and therefore a different system might be most suited.
This article covers each revenue stream in turn with current UK figures and worked examples. It ends with a summary table you can use as a quick appraisal reference.
Financial stream 1: electricity cost savings
Electricity savings are the primary financial element for any commercial solar carport. The carport generates power during daylight hours. That power flows to the building, displacing electricity you would otherwise buy from the grid from between 28 and 32p/kWh.
The financial value of that displacement is not small. A 50-bay commercial carport typically supports around 90-125kWp of installed capacity. In UK conditions, that generates 77,000-113,000kWh per year.
What the numbers look like
At a commercial electricity rate of 28-32p/kWh, self-consumed on-site, a 100kWp carport system saves between £22,000 and £32,000 per year in avoided grid costs. That annual figure compounds across a 25-year system life. By year 25, at a conservative 2% annual energy price increase, the cumulative saving on a 100kWp system is in the range of £700,000-£800,000.
The key variable is the self-consumption rate: what proportion of generated electricity is used on-site rather than exported. For a commercial site with operations running during daylight hours, such as manufacturing plants, logistics hubs, food production facilities and office campuses, typically, self-consumption rates of 70-90% are achievable without battery storage.
Every unit consumed on-site saves 28-32p. Every unit exported earns 5-15p via the Smart Export Guarantee (SEG). The financial gap between those two figures is why self-consumption is the number to optimise.
Worked example: 100kWp carport, Midlands logistics site Annual generation: 90,000kWh. Self-consumption at 80%: 72,000kWh on-site. Saving at 29p/kWh: £20,880/year. Export (18,000kWh at 7p): £1,260/year. Total electricity revenue: £22,140/year. |
One practical advantage carports have over rooftop systems is orientation freedom. A rooftop installation is constrained by whatever way the building faces. A carport can be designed to face south regardless of building orientation, which typically adds 15-25% to annual generation compared to an equivalent east or west-facing roof installation.
Insert case study of brioche
Revenue stream 2: EV charging income
EV charging is the revenue stream most businesses underestimate when they first appraise a solar carport project. It is also, on the right site, the one that grows fastest over the life of the installation.
The principle is straightforward. The solar canopy generates electricity above the bays. EV chargers installed below use that electricity to charge staff or visitor vehicles. The business either provides this as a staff benefit or charges drivers per kWh, generating direct income from electricity produced at an effective cost of around 5-7p/kWh.
Two models for EV charging revenue
Staff benefit model: Provide free or subsidised workplace charging as an employee benefit. No direct charging income, but the perk supports talent retention, reduces employee commuting costs substantially and satisfies a growing expectation among EV-driving staff. The electricity still costs the business 5-7p/kWh effective cost rather than the 28-32p grid rate, so the benefit is delivered at a fraction of its perceived value.
Paid charging model: Charge drivers per kWh at rates of 30-50p/kWh for a standard 7kW workplace charger, or 40-60p/kWh for faster 22kW units. Solar electricity produced at 5-7p/kWh and sold at 30-50p/kWh generates a meaningful gross margin per charge.
Spirit Energy's calculation is useful here: at a 13p margin above electricity supply cost, 25kWh per charge across 250 days per year produces around £813 gross profit per chargepoint annually. A 10-charger installation produces around £8,000 in annual gross profit from EV charging alone, before accounting for infrastructure and management costs.
That figure scales. A major logistics employer with 200 staff vehicles, half of which are EVs by 2028, is looking at a meaningfully different revenue calculation.
The Workplace Charging Scheme
The government's Workplace Charging Scheme (WCS) provides up to £350 per socket for up to 40 sockets, capped at £14,000 per site. This reduces the capital cost of the charging infrastructure itself. The scheme is delivered through OZEV and requires chargers to be installed by an OZEV-authorised installer. The separate EV Infrastructure Grant for SMEs closed on 31 March 2026, so the WCS is now the primary grant route for workplace charging installations.
EV charging revenue note Businesses with destination car parks, retail sites, or public-facing facilities can also consider leasing charging bays to a charge point operator (CPO) in exchange for a fixed monthly fee per bay. This removes all capital and operational risk from the business while generating passive income from car park space. Rates vary by location and footfall but typically run from a nominal land fee to several hundred pounds per bay per year for high-footfall locations. |
Revenue stream 3: Smart Export Guarantee payments
Any electricity generated by a solar carport that is not consumed on-site or used to charge EVs can be exported to the grid and paid for through the Smart Export Guarantee (SEG). This applies to systems of any size, provided the installation is MCS-certified.
SEG export rates in July 2026 range from 5p to 15p/kWh depending on the tariff. Standard commercial export tariffs from most suppliers sit at 5-8p/kWh. Premium time-of-use tariffs (British Gas Export and Earn Plus, Octopus Agile) can reach 12-15p/kWh for export during peak demand periods.
How significant is SEG revenue?
On a well-designed commercial carport with high self-consumption, SEG income is the smallest of the four revenue streams. That factor is by design. Every unit exported at 7p/kWh is a unit not consumed on-site at a saving of 29p/kWh. The financial priority is always to maximise on-site use.
Where SEG income becomes more significant is on sites where operational hours do not align well with peak solar generation, such as a car park at a venue that is primarily busy evenings and weekends, or a site with substantial seasonal generation during summer holiday shutdowns. Battery storage, covered in the context of self-consumption above, is often the better solution for these cases because it shifts generation to when the site is active, earning 29p/kWh rather than 7p.
That said, SEG income is consistent, reliable, and requires no management once the connection and tariff are in place. It should always be modelled in a carport financial appraisal even when it is not the primary return driver.
Provider | SEG tariff name | Export rate (July 2026) | Notes |
Octopus Energy | Agile Outgoing | 5p-15p/kWh (variable) | Time-of-use; peaks during high demand periods |
British Gas | Export and Earn Plus | Up to 15p/kWh | Premium rate; MCS required |
EDF Energy | SEG tariff | 4.1p/kWh | Fixed rate |
E.ON Next | SEG tariff | 4p/kWh | Fixed rate |
Standard commercial range | Various | 5-8p/kWh | Typical fixed rate for commercial sites |
Source: Ofgem SEG register, July 2026. Rates subject to change. Verify current rates at ofgem.gov.uk/seg before financial modelling.
Financial stream 4: Annual Investment Allowance tax relief
For a profitable UK limited company, the AIA is the most immediate financial return a solar carport delivers. It is also the one most frequently missed in early appraisals because it does not appear in a cash flow model until the business's tax return is filed.
The Annual Investment Allowance allows UK businesses to deduct 100% of qualifying plant and machinery expenditure from taxable profits in the year of purchase, up to a cap of £1 million per accounting period. Commercial solar panels qualify as plant and machinery. The AIA is permanent with no current end date.
What this means in practice
For a profitable limited company paying the main rate of corporation tax at 25%, the AIA returns 25p of every pound spent on a solar carport as year-one tax relief.
On a £500,000 carport installation, that is £125,000 in tax relief in year one. The carport effectively costs £375,000 net of tax. That materially changes the payback calculation and the IRR.
The AIA applies to the photovoltaic (PV) panels and inverters. Whether the steel structure itself qualifies depends on how it is classified. Your accountant should confirm the qualifying elements before the project is structured, as this affects the total relief available. Most single-site carport installations fall within the £1 million AIA cap and can be fully expensed in one year.
AIA example on a £400,000 carport Pre-tax cost: £400,000. Corporation tax saving at 25%: £100,000. Net cost after year-one AIA relief: £300,000. This is captured in the year the installation is brought into use, not spread over the life of the asset. |
For businesses that have already used their AIA against other equipment in the same accounting period, the 50% First Year Allowance (FYA) applies to the remainder. Above the £1 million AIA cap, the Special Rate Pool provides writing-down allowances at 6% per year on a reducing balance. For most single-site installations, the AIA covers the full cost.
Note: solar is a special rate asset under HMRC rules, which means it does not qualify for full expensing (the 100% main-rate relief available since April 2023). The AIA is the correct route, and it achieves the same outcome for any installation below £1 million.
All four financial streams: what the combined return looks like
The table below pulls together indicative annual quantum from each stream for three carport sizes. All figures are illustrative and based on a south-facing, Midlands installation with 80% self-consumption, standard commercial electricity rate of 29p/kWh, SEG export at 7p/kWh, and AIA expressed as a year-one equivalent annual figure over a 10-year appraisal period.
Financial stream | 50kWp carport (~25 bays) | 100kWp carport (~50 bays) | 200kWp carport (~100 bays) |
Electricity savings (on-site) | ~£10,000-£12,000/yr | ~£20,000-£24,000/yr | ~£40,000-£48,000/yr |
EV charging income (10 chargers, paid model) | N/A - scale dependent | ~£6,000-£8,000/yr | ~£12,000-£16,000/yr |
SEG export (20% of generation) | ~£700-£1,000/yr | ~£1,400-£2,000/yr | ~£2,800-£4,000/yr |
AIA tax relief (year 1 only, 25% CT) | ~£50,000-£70,000 | ~£100,000-£140,000 | ~£200,000-£280,000 |
Year 1 total (inc. AIA)
| ~£62,000-£83,000 | ~£127,000-£174,000 | ~£255,000-£348,000 |
Annual total (years 2+, ex-AIA) | ~£10,700-£13,000/yr | ~£27,400-£34,000/yr | ~£54,800-£68,000/yr |
All figures are indicative. Site-specific generation, self-consumption rate, energy tariff, and charging utilisation rates will all affect actual returns. A feasibility assessment produces precise projections for your site.
Which commercial sites generate the strongest carport returns?
Not every car park is equally suited to a solar carport. The sites that generate the best returns share a consistent set of characteristics as summarised below.
High daytime energy consumption
The financial case for a carport depends on self-consumption. A site whose operations run 9am-5pm, Monday to Friday, has a near-perfect alignment between solar generation and on-site demand. Manufacturing plants, food production facilities, office campuses and retail parks all fit this profile well.
A venue that is primarily busy evenings and weekends, with a largely empty car park during peak solar hours, will export more generation and self-consume less. The electricity revenue is lower; EV charging income and battery storage become proportionally more important.
Large car parks with good solar access
Carport economics improve with scale. A 100-bay installation has significantly lower per-kWp structure costs than a 20-bay installation because fixed costs relating to civil works, grid connection and design fees are spread across more generating capacity. Sites with 40 bays or more are the sweet-spot where carport economics consistently make sense.
Solar access matters too. A car park surrounded by tall buildings or heavily shaded by mature trees will generate significantly less than an open, south-facing equivalent. An initial shading analysis is always worth commissioning before committing to a carport project.
High EV adoption among staff or visitors
A logistics business with 200 HGV drivers is a different EV charging opportunity than an office of 200 knowledge workers with company car policies. Sites where staff or visitor EV adoption is already high, or where company car fleet electrification is planned, will see EV charging revenue ramp-up faster and reach higher utilisation rates sooner.
The forward projection matters here. A carport installed in 2026 will still be generating in 2051. The EV charging revenue modelled conservatively today will look very different in five years as fleet electrification accelerates.
Solar carport versus rooftop solar: which makes more financial sense?
This is a question we often get asked directly.
For most businesses with usable roof space, a rooftop installation is the more capital-efficient starting point. The structure is already there. You are installing panels and mounting equipment on an existing asset, not building a new canopy structure from the ground up. The per-kWp installed cost is lower.
However, a solar carport makes stronger financial sense in four specific situations:
No usable roof space: asbestos cement sheeting, north-facing orientation, structural load limits or a building the landlord will not permit modifications to. The car park becomes the viable generation site when the roof is ruled out.
EV charging is a priority: the dual purpose of shelter and generation, with EV charging infrastructure integrated below, is a combination a rooftop system cannot replicate.
Roof solar is already maximised: a business that has filled its south-facing roof capacity and wants to increase total generation size can add a carport alongside the existing rooftop system without a significant grid connection upgrade in most cases.
Planning and aesthetics: a solar carport is a visible demonstration of sustainability commitment in a way a rooftop system is not. For businesses with public-facing premises, a carport can serve a brand communication purpose that adds value beyond the energy numbers.
On sites where both options are genuinely available, the right answer usually starts with the roof and adds a carport as phase two once the roof investment is generating returns. That sequencing spreads capital, proves the technology to the business internally and allows the EV charging case to mature alongside actual fleet electrification rates.
How Eden Sustainable approaches carport revenue modelling
We have been installing commercial solar since 2014. Carports have been part of our project portfolio for several years, and the most important thing I would tell any business considering one is this: the financial case lives or dies on how honestly all four financial streams are modelled.
We have seen proposals where the EV charging revenue is projected at full utilisation from day one. It never works that way. EV adoption among staff ramps over 12-24 months. Charging utilisation builds gradually. A well-structured financial model will show a lower year-one EV income than full potential, scaling to a realistic stabilised figure by year three.
The AIA is the one that surprises people most positively. A business that has not run the tax calculation before we share it often underestimates by a factor of two or three how much of the first-year cost is effectively funded by HMRC. On a £600,000 project, that is £150,000 arriving in the tax return year. For a Finance Director trying to justify the investment to a board, that number changes the conversation.
The right starting point is a feasibility assessment that models all four streams against your actual site data, your energy consumption profile, and your fleet electrification timeline.
That conversation costs nothing and commits you to nothing – and you'll be much better informed afterwards.
Frequently asked questions
How much revenue can a commercial solar carport generate per year?
Electricity savings, EV charging income, SEG export and the AIA combined can reach £30,000-£50,000 in year one for a well-sited 50-100 bay installation, with the AIA element being the largest single figure but a one-time benefit. From year two onwards, ongoing annual revenue from electricity savings and EV charging typically runs at £20,000-£40,000 per year for a 100kWp installation, depending on self-consumption rate and charging utilisation.
Does a solar carport qualify for capital allowances?
Yes. The solar panels and inverters qualify as plant and machinery and are eligible for the Annual Investment Allowance, which provides 100% first-year tax relief up to £1 million per accounting period. For a profitable limited company, that is worth 25p in tax relief for every pound of qualifying spend. The structural steelwork may attract a different treatment; confirm with your accountant before structuring the project.
Is EV charging revenue guaranteed?
No. EV charging income depends on utilisation, which ramps over time as EV adoption among staff or visitors grows. A conservative financial model will project EV charging revenue at 40-60% of theoretical maximum in year one, increasing to 70-85% by year three. Sites with strong existing EV adoption among staff will reach stabilised utilisation faster. The Workplace Charging Scheme reduces the capital cost of the charging infrastructure itself.
Can a carport work financially without EV charging?
Yes, though the payback period is longer. Electricity savings and SEG income alone on a 100kWp carport deliver around £20,000-£26,000 per year. Add the AIA in year one and the net payback period shortens considerably. Whether EV charging is included depends on your site and fleet profile, not on whether the project is financially viable without it.
Does a solar carport need planning permission?
Almost always yes. Unlike most rooftop solar installations, which fall under permitted development rights, commercial solar carports are freestanding structures and typically require full planning permission. The process adds 8-16 weeks to the project timeline compared to a rooftop installation. Early engagement with the local planning authority is advisable, particularly for larger installations or sites in sensitive areas.
What is the payback period for a commercial solar carport?
Payback periods for commercial solar carports typically run 5-10 years depending on installation size, self-consumption rate, EV charging utilisation, and whether AIA relief is claimed. Larger installations with high self-consumption and active EV charging programmes are at the shorter end of that range. The AIA claimed in year one effectively accelerates payback by reducing the net invested cost.
