Commercial Solar Panel Cost UK: Prices by System Size in 2026

Most UK commercial solar installations cost £700 to £1,100 per kWp, fully installed and excluding VAT. The price per kWp falls as the system gets larger, because the fixed costs of a project (design, survey, scaffolding, site set-up and the grid application) are spread across more panels.

As a rough guide to how the rate changes with scale:

• Small systems under 50kWp: around £1,000 to £1,200 per kWp
• Medium systems of 50 to 250kWp: around £800 to £1,000 per kWp
• Large systems of 250kWp and above: around £700 to £850 per kWp, and lower again on very large, simple roofs

Commercial solar is cheaper per kWp than a typical home installation. A domestic system often works out at £1,400 or more per kWp, because a 4kW roof still needs the same scaffold, the same electrician's visit and the same paperwork as a much bigger job. A business paying £0.85 per watt rather than £1.40 is not getting inferior kit. It is benefiting from scale.

These indicative ranges are for straightforward rooftop installations, excluding VAT. Each 1kWp of panels needs roughly 5 to 6 square metres of usable roof.

• 10kWp (about 23 panels): £11,500 to £14,000. Small office, shop or workshop.
• 30kWp (about 70 panels): £30,000 to £36,000. Small hotel, restaurant or light industrial unit.
• 50kWp (about 115 panels): £40,000 to £52,000. Small factory, farm building or large office.
• 100kWp (about 230 panels): £80,000 to £100,000. Medium warehouse, school or manufacturing site.
• 250kWp (about 580 panels): £175,000 to £215,000. Large retail unit, distribution centre or supermarket.
• 500kWp (about 1,160 panels): £325,000 to £400,000. Large warehouse or factory.

Panel counts assume modern modules of around 430 watts each. Higher-wattage panels need fewer units for the same output, which can trim mounting and labour costs slightly.

Treat these as budgeting figures rather than quotes. Two buildings needing the same 100kWp system can be priced £20,000 apart once roof construction, access and grid connection are taken into account.

A complete commercial solar price covers far more than panels. On a typical project the panels themselves account for well under half the cost. A full quote should itemise:

• Panels: manufacturer, model, wattage and warranty. Common choices include LONGi, JA Solar, Trina, Jinko and Aiko.
• Inverters: string inverters from brands such as SMA, Huawei, Solis, Fronius or SolarEdge, plus any optimisers.
• Mounting system: rails, clamps or ballast, matched to your roof type.
• Electrical works: DC and AC cabling, isolators, switchgear, protection and the connection into your main distribution board.
• Access and safety: scaffolding, edge protection, mobile elevating work platforms and, on fragile roofs, safety netting.
• Design and compliance: structural calculations, the yield simulation and the G99 grid application.
• Commissioning and handover: testing, certification, monitoring set-up and an operation and maintenance manual.

If a quote gives a single lump sum with no breakdown, ask for one. Itemised quotes are the only way to compare installers fairly and to see where a price difference really comes from.

The roof is the biggest variable after system size. Trapezoidal metal sheeting is the cheapest roof to work on, because rails fix directly to the profile. Standing seam roofs use non-penetrating clamps and are similarly quick. Flat membrane roofs usually need ballasted frames, which add weight and need a structural check.

Fibre cement roofs are where costs rise. Many are fragile, and sheets installed before 2000 may contain asbestos. Panels should not be fixed into asbestos cement, because work that disturbs it is regulated under the Control of Asbestos Regulations 2012. After an asbestos survey, the usual answer is to over-clad the roof with new metal sheeting or replace it before fitting solar, which changes the budget completely.

Other factors that add cost:

• Height and access: tall buildings, restricted yards and live loading bays push up access costs.
• Cable runs: a long distance between the array and the main switchroom adds cabling and labour.
• Out-of-hours working: sites that cannot tolerate daytime disruption pay a premium for evening or weekend shifts.
• Electrical upgrades: older switchgear may need replacing before it can accept a generator.

The single most unpredictable line in a commercial solar budget is the grid connection, and it is rarely the one buyers ask about. Any system above 16 amps per phase, which is 11.04kW on a three-phase supply, needs approval from the distribution network operator (DNO) under the G99 process before it can be switched on. That covers almost every commercial installation.

The DNO can approve the connection as requested, approve it with an export limit, or require reinforcement of the local network at your cost. Reinforcement can run into tens of thousands of pounds on a constrained network. The difference between a premium panel brand and a mid-range one on a 100kWp system is often only a few thousand pounds, so the connection can move the final price far more than the kit choice.

Two things protect your budget. First, ask installers to submit the G99 application early, before you commit to a final design. Second, ask whether an export-limited design would avoid reinforcement. If most of your generation will be used on site anyway, capping export often costs you very little in lost income while removing a large and uncertain charge.

Commercial battery storage typically costs around £400 to £700 per kWh of installed capacity for systems of 50 to 500 kWh, with larger systems at the lower end and some simple modular systems quoted below that. A 50kWh battery alongside a 50kWp array might add £25,000 to £35,000 to the project. Common commercial options include systems from Pylontech, BYD, Huawei and Solis, and larger containerised units for industrial sites.

A battery makes financial sense when there is a real gap between when you generate and when you use power, for example a business that trades into the evening, or a site that would otherwise export a large share of its summer output for a few pence per unit. It can also earn money by charging from the grid at cheap overnight rates and discharging at peak times, if your tariff has a strong enough price difference.

For a typical office or factory that uses most of its solar output during working hours, a battery often lengthens the payback rather than shortening it. Ask installers to model the system with and without storage, using your own consumption data, before deciding.

Solar has low running costs, but they are not zero. Budget for:

• Operation and maintenance (O&M): an annual inspection, electrical testing and monitoring review. Larger sites usually take an O&M contract priced per kWp per year.
• Inverter replacement: panels typically carry 25 to 30-year performance warranties, but string inverters are commonly warranted for 5 to 12 years. Plan for at least one inverter replacement during a 25-year life.
• Cleaning: low-pitch roofs near farms, quarries or busy roads collect dirt that reduces output. Many sites clean every one to two years.
• Insurance: tell your buildings insurer about the installation. Some policies need updating to cover the array and any change in fire risk.
• Monitoring: most inverters include free monitoring portals, but some businesses pay for third-party monitoring across several sites.

Panels also lose a little output each year, typically around 0.4% to 0.5% for modern modules, so a good financial model shows generation declining gradually rather than staying flat for 25 years.

Every unit of solar electricity used on site replaces a unit bought from the grid. Government figures put the average non-domestic electricity price at about 24p per kWh in early 2026, and smaller businesses typically pay 25p to 29p. A 100kWp system generating 85,000 to 105,000 kWh a year can therefore displace £20,000 or more of electricity annually if most of the output is used on site.

Two tax measures improve the numbers further, and both are commonly underplayed in sales conversations:

• Capital allowances: solar panels are special-rate plant and machinery, and the Annual Investment Allowance lets most businesses deduct qualifying spend of up to £1 million in full from taxable profits in the year of purchase.
• Business rates: in England, eligible on-site renewable generation and storage is exempt from business rates until 31 March 2035, so a rooftop system should not increase your rateable value.

How these apply depends on how your business is structured and how the system is owned, so confirm the treatment with your accountant before relying on it in a business case.

Buying outright gives the strongest long-term return. You own the system, take all the savings and can claim the capital allowances. It suits businesses with cash available and a site they expect to occupy for the long term.

The main alternatives are:

• Asset finance: spreads the cost over a fixed term, often three to seven years. Because the business usually owns the equipment, the capital allowances generally remain available, and on a good site the energy savings can exceed the repayments from the first year.
• Leasing: similar monthly payments, but the lessor owns the system during the lease, which changes who can claim the tax relief.
• Power purchase agreement (PPA): a funder installs and owns the system at no upfront cost, and you buy the electricity it generates at an agreed rate per kWh, often quoted around 10p to 15p. You save less than an owner would, but you take no capital risk.

PPAs usually require a larger roof, a long remaining lease or freehold, and a strong covenant, so they tend to suit bigger sites rather than small businesses.

The only reliable price for your building comes from a site survey and a design based on your own energy data. Before you request quotes, gather 12 months of electricity bills or, better, half-hourly consumption data from your supplier, along with roof drawings or the building's age and construction if you know them, and your normal opening hours.

When the quotes arrive, compare them on price per kWp and on predicted annual generation, not on the headline total. A cheaper quote that predicts lower generation can be worse value than a dearer one. Check what is excluded, especially scaffolding, grid application fees, network reinforcement and any roof repairs.

You can learn more about system types and installation options on our commercial solar page, and see how output varies by location on our solar panels by area pages. When you are ready, compare quotes from up to three MCS-certified commercial installers for your site.