Commercial Solar Panel Cost in 2026: Price per kWp, Payback and ROI

Commercial solar panel cost per kWp in 2026

Two UK guides publish a price for each system size, and they do not agree. So the table shows each figure with its publisher and date. All are installed prices, ex VAT. They are published market figures, not Craftex quotes.

Roof needed is our arithmetic on a rule of thumb of about 6 m² per kWp (Utilita Business). Evo Energy adds that systems of 1 MWp and above often come in under £700 per kWp.

Why cost per kWp falls with size

Cost per kWp falls as the system grows because the design, survey, inverter and connection work is paid once. Solar-Voltaics' own bands slide from £560 to £810 per kWp at 30 kWp to £500 to £750 at 250 kWp. The two guides still differ by £18,000 at 100 kWp, so compare quotes on the same basis.

For a rough check, our solar page has a calculator. It uses £110 per m² of usable roof for arrays of 250 kWp and above, and £130 below that. That is indicative and ex VAT. A survey turns it into your figure.

What sits on top of the panel price

The tables above price the array. A quote for a real building adds the lines below. No guide prices them as a set, and we price them only from a survey.

1. The roof. About 35% of 575 surveyed commercial roofs needed remedial work before panels. About 5% could not take them at all (Solar Surveys, via Insurance Times). A full re-roof runs £90 to £180 per m² (MyJobQuote, 2026), or £54,000 to £108,000 over 600 m². Our guide to commercial roof replacement cost sets out the options.
2. The structure. Panels, frames and ballast add weight. An engineer checks the roof structure first. A weak roof may need a lightweight system.
3. Scaffold and edge protection. Working at height needs safe access and edge protection. On a live site, crane lifts and access routes are planned around trading.
4. Grid connection. Generation above 16 A (3.68 kW) per phase needs approval from the network operator under G99. Network works, where needed, are charged to the project.
5. The insurer. Insurers judge rooftop PV against RC62, the fire code from RISCAuthority and the Fire Protection Association. Ask yours for its conditions before the design is fixed.
6. Battery, chargers and monitoring. These are optional, priced separately, and covered below. A maintenance contract is also a running cost: Evo Energy puts it at £3,000 to £10,000 a year for a 500 kWp system.

Rooftop solar on a non-domestic building in England is usually permitted development, and the 1 MW limit was removed from 21 December 2023. Check listed status and conservation areas with the council first.

Roof first, then panels

A roof that must be repaired first changes the sum. The cheapest array on a roof with a few years left is often the dearest one. We run commercial solar installation and the roof works under one contract, so the date and the warranty have one owner. Get a free solar survey and payback estimate.

Commercial solar payback and ROI

Payback is the installed cost divided by what the array saves each year. The saving is the power you use yourself, multiplied by the price you would have paid for it. Exported power earns the export rate, which this example leaves out.

Published paybacks run wide, and the reason is self-use:

To see the effect, take a 100 kWp array at £80,000, the middle of Evo Energy's £70,000 to £90,000. It makes 85,000 kWh a year at 850 kWh per kWp. Each kWh used on site saves 28p. The table changes only the share used on site.

This is a method, not a Craftex result. It leaves out export income, maintenance and the 0.4% to 0.5% a year that panels lose output. Replace the 28p with your own tariff, and the 850 kWh with your roof's yield.

Self-use beats export. A site busy through daylight hours, such as a factory on day shifts, sits near the top of the table. A building that is empty at weekends sits near the bottom.

Export is paid under the Smart Export Guarantee, up to 5 MW. Each licensed supplier sets its own rate, which must always be above zero. Ask for the rate in writing, as it changes.

Tax relief: capital allowances and business rates

Solar panels are special rate expenditure under section 104A(1)(g) of the Capital Allowances Act 2001, added in 2012. It matters because the allowance depends on the pool the cost goes into.

A company can claim a 50% first-year allowance on special rate expenditure on new, unused plant. That comes from section 45S and the table in section 52, and the section has no end date. The balance stays in the pool and is written down over later years.

The Annual Investment Allowance is £1 million a year. It can cover most plant and machinery, for companies, sole traders and most partnerships. Companies controlled by the same person share one allowance. You cannot claim both allowances on the same cost. Our guide to capital allowances on commercial property covers the wider rules.

In England, panels and the batteries that store their power are also left out of the building's rateable value. That applies to days before 1 April 2035, under regulation 2 of SI 2022/405. The array does not raise your business rates bill.

Buy, lease or PPA

There are three ways to pay for commercial solar. The choice decides who owns the array, who gets the saving and what the roof must allow.

A PPA moves the cost and the risk to the provider and takes much of the saving with it. Buying costs more at the start and keeps the allowances. Whichever route you take, the roof must carry the system for the length of the contract.

The lease comes first. A tenant normally needs the landlord's licence to alter the roof, and the lease should say what happens to the panels at the end. A landlord can sell the power to its tenants, but each tenant needs its own contract. Ask your solicitor to read both, ahead of any design work.

For landlords there is a second reason to look. Solar can help a building toward a better EPC rating. EPC B by 2031 is proposed for let commercial buildings, not yet law. Our guide to MEES rules for commercial landlords sets out where that stands.

Battery storage and grid connection costs

A battery stores midday output for the evening. Published prices fall with size, as the figures below show. They are installed prices from Reonic (20 July 2026), citing Heatable.

A battery pays when much of your load falls after dark, or when much of the output would be exported. Evo Energy says self-use rises from 30% to 40% without a battery to 60% to 70% with a well-sized one. Reonic gives paybacks of 4 to 10 years. Size it from half-hourly data.

For a house rather than a site, see what a solar battery costs.

Grid connection and G99

Grid connection is the other cost that surprises buyers. Generation above 16 A (3.68 kW) per phase needs G99 approval. UK Power Networks asks for a notification under 5 kW. From 5 kW to 50 kW, the installer applies on its online portal. At 50 kW and above, the project follows a step-by-step process.

The operator's answer can set both the date and the cost, because it may require network works. Apply straight after the survey. Ask whether limiting the export would avoid reinforcement. No guide we found gives a reliable fee or timescale, so we state none.

We build for sites that cannot stop. At Banbury Warehouse we fitted out 148 sq m inside a live warehouse in 4 weeks, and operations never stopped. It was not a solar job, but the discipline is the same.

Gather these before you ask for a quote. They let a firm size the array and price the roof without a second visit.

Ready to price yours? Get a free solar survey and payback estimate. Send the last year of bills and the site address. Roof drawings and phone photos help. We inspect the roof covering, structure and incoming supply. Then we return a payback estimate and a programme counted back from your date, at no charge and with no obligation.