Installing a solar carport with EV charging: how it works

Solar carports and EV charging get sold as two separate projects. They should not be. Retro-fitting chargers to a canopy that was never wired for them means trenching back through fresh tarmac, upsizing a grid connection you have already paid for, and applying to your Distribution Network Operator twice. Get the sequencing right and the two systems share one connection, one set of civils and one design intent. Get it wrong and you pay for the same groundworks twice.

This guide walks through how a combined solar carport installation with EV charging actually goes together on a commercial site, and where the real decisions sit.

Why the electrics are decided at groundworks, not at handover

The single most expensive mistake is treating charging as a phase-two add-on with no phase-one provision. When our installers dig the footings for the carport steel, that is the moment to lay the charger conduit and reserve grid headroom, even if the chargers themselves land months later.

Two things get designed in at civils stage:

• Conduit and duct routes. Oversized ducting runs from the incoming supply and the inverter position out to every intended charging bay. Pulling cable through empty ducts later is a day’s work. Excavating a finished car park to add them is a job that can cost more than the chargers.
• DNO capacity headroom. The solar array and the chargers both draw on the same connection. You size the incoming supply for the whole scheme now, not just the panels, so there is spare capacity to energise chargers without a second, slower application later.

If the budget only stretches to solar in year one, you still lay the ducts and reserve the capacity. That provision is cheap. Retro-fitting it is not.

For the full civils and mounting sequence, see how solar carports are installed.

How the solar actually feeds the chargers

The solar does not “charge the cars” in any romantic sense. It feeds the building’s electrical system behind the meter, and the chargers draw from that same system. When the sun is on the array and a car is plugged in, the electrons take the short path: panel to charger, never touching the grid.

The commercial logic is simple. Every kilowatt-hour a charger pulls from your own carport is a kilowatt-hour you did not import at the grid rate. You are effectively charging vehicles at your solar generation cost rather than your import tariff. On a workplace or fleet site where cars sit for hours during the day, that overlap between generation and demand is close to ideal.

Two engineering details make this work in practice:

• Load balancing. Dynamic load management shares the available capacity across all the sockets and the rest of the building, throttling charge rates so the site never trips its connection limit. A car park of chargers rarely all pulls maximum power at once, and the controller manages that.
• Cable sizing. The feed to the charger array is sized for either the full simultaneous load or the load-management ceiling you have set. Undersize it and you cap your future charging capacity; oversize it sensibly and you leave room to add sockets later on the ducts you already laid.

AC charging suits solar. Rapid charging needs the grid and often a battery

Not every charger belongs on a carport, and this is where honest design matters.

AC chargers (typically 7–22 kW) are the natural partner for carport solar. They suit long-dwell parking: staff cars, visitor bays, fleet vehicles parked through the working day. A carport array generating steadily can comfortably supply a bank of AC sockets while cars sit and sip. This is the combination most commercial sites should build.

DC rapid chargers (50 kW and up) are a different animal. A single rapid charger can draw more power in a few minutes than the whole carport produces in an hour. Solar alone cannot sustain that. Rapid charging leans on the grid connection, and on many sites a battery is added to buffer the demand, shave the peak and avoid an expensive connection upgrade. If your site needs rapid charging, plan for grid capacity and storage from the outset; do not expect the panels to carry it.

The rule of thumb: match generation to dwell time. Long dwell, AC, solar-native. Short dwell, DC rapid, grid plus battery.

The Workplace Charging Scheme grant

The Workplace Charging Scheme (WCS) reduces the cost of the charger sockets themselves. As it stands, it contributes £500 per socket, up to 75% of the purchase and installation cost, on up to 40 sockets across your sites. State-funded education institutions can claim a higher rate of £2,000 per socket. The scheme runs to 31 March 2027.

WCS applies to the charging hardware, not to the solar carport structure. It works alongside the wider capital allowances available on the solar side, so the two funding routes stack rather than compete. Eligibility rules and the voucher process change from time to time, so confirm current terms before you build the numbers into a business case; we keep the detail current on the grants and funding page.

DNO approval is the item that sets your timeline

If one thing dictates when your site goes live, it is the DNO application. Connect anything that generates or draws significant power and your network operator has to sign it off.

• G98 is the fit-and-inform route: it applies only to small generation up to 3.68 kW per phase, where you notify the DNO after connection.
• G99 is the pre-approval route for anything above that threshold, which covers essentially every commercial carport installation. You apply, wait for the connection offer, and cannot energise until it is granted.

G99 approval commonly takes 8 to 16 weeks, and on constrained parts of the network it can run longer. It is almost always the longest lead item on the programme, longer than manufacturing the steel or installing the panels. The practical consequence is to submit the DNO application early, and to apply once for the combined solar-plus-charging load rather than twice. This is another reason the charging capacity is designed in at the start: a single G99 for the whole scheme beats a second application when you come to add chargers.

What it costs, and how the tax works

Carport solar costs more per kilowatt than rooftop, because you are paying for a structure as well as an array. As a working guide, expect roughly £1,100–£1,600 per kWp at scale, rising towards £1,200–£3,000 per kWp on smaller schemes, or around £6,000–£12,000 per parking space before VAT. That is broadly two to three times the cost of an equivalent rooftop system, where the steel structure alone is typically 40–50% of the total. The chargers, cabling and load management sit on top of that, partly offset by WCS.

Commercial quotes are given excluding VAT, because the 20% is recoverable for VAT-registered businesses. The 0% VAT rate is a residential measure only and does not apply to commercial installations. On the tax side, solar PV is special-rate plant, so it does not qualify for full expensing. It is eligible for the Annual Investment Allowance at 100% up to £1m, and companies can also claim the 50% First Year Allowance on qualifying special-rate expenditure. In England, eligible solar generation equipment is exempt from business rates until 31 March 2035, though that relief does not extend to Wales or Scotland. These are general points, not advice for your accounts; take your own tax advice before committing.

For a fuller breakdown of the numbers, see the cost guide.

Output you can plan around

A typical carport bay carries around 2 kWp of panels. At the UK national yield of roughly 900–950 kWh per kWp, that works out to about 1,700–2,000 kWh per bay per year. There is no single guaranteed figure, orientation, shading and roof pitch all move it, but that range is a sound planning baseline. A modest staff car park covering, say, forty bays therefore generates a meaningful share of a workplace charging load without touching the grid.

Payback on solar alone typically lands around 8 to 10 years. Adding EV charging usually shortens it, because self-consuming your generation to power vehicles displaces expensive imported electricity rather than exporting it cheaply.

One project, sequenced right

The combined install is not complicated once the order is respected. Reserve the grid capacity and lay the conduit at groundworks. Submit a single G99 for the whole load early, because it is the long pole. Feed AC chargers from the carport behind the meter, and reach for a battery and grid capacity only where rapid charging demands it. Claim WCS on the sockets and the capital allowances on the array. Sites vary by sector, from retail and leisure car parks to fleet depots and workplace parking; browse the sectors we cover to see how the design shifts.

Planning is rarely the obstacle it is assumed to be. In England, most ground-mounted and canopy solar now proceeds under a prior-approval right rather than full planning permission, with surface-water run-off handled as a condition. It is a standing entitlement, not a closing window, so there is no need to rush a decision on that account.

If you want a combined solar carport installation and EV charging scheme costed properly, with the DNO timeline and grant eligibility mapped out before you commit, request a quote and we will work through it with you.