Key facts for 2026
How much do commercial solar panels cost in 2026?
The only official national price series is DESNZ's small-scale solar cost data, built from the MCS installation database. It covers systems up to 50kW, which takes in most SME, farm and school roofs. Above 50kW, installers price each project on survey, and the cost per kW usually keeps falling as the system gets bigger.
| System size | Typical roof | Cost per kW (DESNZ 2025/26) | Illustrative installed cost |
|---|---|---|---|
| 4-10kW | Shop, café, surgery, small workshop | Non-domestic 4-10kW average, £1,533/kW | £15,300 for 10kW |
| 10-50kW | Office, school block, farm building, small unit | 10-50kW median, £1,262/kW (non-domestic average £1,259/kW) | £37,900 for 30kW, £63,100 for 50kW |
| 50-250kW | Warehouse, factory, distribution unit, large barn | Bespoke quote, not covered by the DESNZ series | Survey-priced; ask for a cost per kWp and a bill-saving model |
| 250kW+ | Big-box logistics, multi-site estates, ground-mount | Bespoke quote, often with a grid application | Often offered on a PPA or lease as well as an outright purchase |
Illustrative costs multiply the DESNZ 2025/26 figures by system size and are rounded. DESNZ costs include equipment, installation, grid connection and VAT where it applies. They exclude batteries and roof repairs. DESNZ measures cost per kW of declared net capacity (DNC). Installers usually quote per kWp of panels, and DESNZ says costs on that basis (total installed capacity) are typically 6-12% lower: the 10-50kW median is £1,204/kWp. Source: DESNZ solar PV cost data, published 28 May 2026.
For 10kW to 50kW prices, regional costs, the 2024/25 to 2025/26 trend and a line-by-line quote checklist, see commercial solar panel costs by system size.
Payback: why daytime electricity use decides everything
A commercial solar system earns money two ways. Every unit you use on site saves your full delivered unit rate, including the non-commodity charges and the Climate Change Levy. Every unit you export earns whatever your Smart Export Guarantee tariff pays, which is usually far less. So the payback depends far more on how much of the solar you use yourself than on the panels you choose.
- Best payback: sites with heavy weekday daytime loads, such as chillers, compressors, production lines, ventilation and air conditioning, which use almost everything the roof makes.
- Good payback: offices, retail and schools, where use drops at weekends or in holidays. A battery or an export tariff picks up the surplus.
- Weakest payback: sites empty in the day that export most of their output. Size the system down, or add a battery.
Ask every installer for: a model built on your half-hourly data (or 12 months of bills), the self-consumption percentage, the export assumption, panel degradation, inverter replacement in the cash flow, and the payback with and without the tax allowance.
Tax breaks that cut the real cost
| Allowance | What it does for solar | Who can use it |
|---|---|---|
| Annual Investment Allowance (AIA) | Deduct 100% of qualifying spend, up to £1 million a year, from taxable profits | Most businesses: companies, sole traders and partnerships |
| 50% first-year allowance | Deduct half the cost of special-rate assets such as solar panels in year one; the rest goes into the special-rate pool | Companies buying new, unused assets (from 1 April 2023) |
| Special-rate pool | Writing-down allowance of 6% a year on the balance | All businesses |
| Full expensing | Not available for solar panels. It covers main-rate plant only, and HMRC designates solar panels as special rate | Companies |
| 40% first-year allowance (from 1 Jan 2026) | Not for solar panels. It applies to main-rate assets only | Includes unincorporated businesses and leased assets |
HMRC's manual is explicit: "all capital expenditure on the provision of solar panels is specifically designated as special rate" (CA22335). So the AIA is the big lever. A company spending £150,000 on a rooftop system can usually deduct the whole lot from that year's profits, as long as the AIA hasn't been used up on other kit.
Business rates matter too. In England, plant and machinery used to generate or store power from on-site renewables (solar included, and batteries where the power stored is mainly or exclusively renewable) is excluded from rateable value until 1 April 2035. Wales (from 1 April 2024) and Scotland (from 1 April 2023) have equivalent exemptions running to 2035. Adding panels to your roof shouldn't raise your rates bill.
For full detail, read our solar panels capital allowances guide. Take advice from your accountant before you claim.
Can a business get solar panels with no upfront cost?
Yes, on bigger roofs. There is no government scheme handing out free commercial solar panels. What does exist is third-party finance: a funder pays for and owns the system, and you buy the electricity it makes at an agreed rate below your grid price (a solar power purchase agreement, or PPA), or you lease the system. Funders usually want a large roof, a long lease or freehold, and a creditworthy occupier.
See commercial solar with no upfront cost (PPA and leasing) for how the deals work and what to check in the contract.
From enquiry to switch-on: the commercial solar process
- Data and desk study. Bills or half-hourly data, roof drawings, and the lease or landlord position.
- Site survey. Roof condition and structure, fragile roof lights, asbestos risk on older sheeting, cable routes and where the inverter goes.
- Grid check. Larger systems need the distribution network operator (DNO) to approve the connection. Export limits can shape the design, and a battery can soak up output you're not allowed to export.
- Design and quote. Panel layout, generation forecast, savings model, warranty terms and the programme of works.
- Consents. Most roof-mounted commercial solar in England is permitted development (the old 1MW cap was removed in December 2023), but bigger non-microgeneration systems need prior approval on glare, and listed buildings always need consent.
- Install and commissioning. Most commercial roofs are installed while the business keeps trading.
- Export tariff and monitoring. Register for the SEG and set up monitoring so you can see the savings.
Commercial solar by sector
How to choose a commercial solar installer
- Commercial track record: ask for completed projects of a similar size and roof type, with references.
- Certification: MCS certification covers systems up to 50kW and is needed for SEG on those systems. Above 50kW, look for relevant electrical competence, design capability and a clear warranty package.
- Roof and structure: a structural survey, and on older industrial roofs an asbestos and fragility check before anyone climbs up.
- Grid: who handles the DNO application, and what happens if an export limit is imposed.
- Warranty and O&M: panel, inverter and workmanship warranties, plus monitoring and maintenance terms.
We introduce your enquiry to one suitable installer that does commercial work. You won't be passed round a list or sold on.
Sources checked 28 October 2026
- DESNZ: Solar PV cost data (2025/26, published 28 May 2026)
- HMRC Capital Allowances Manual CA22335: solar panels are special rate
- GOV.UK: full expensing and the 50% first-year allowance
- GOV.UK: Annual Investment Allowance (£1 million)
- Valuation for Rating (Plant and Machinery) (England) (Amendment) Regulations 2022 (SI 2022/405)
- Wales: Plant and Machinery (Amendment) Regulations 2023
- Scotland: Valuation (Plant and Machinery) Amendment Regulations 2023
- Ofgem: Smart Export Guarantee
- GPDO 2015 Schedule 2 Part 14: permitted development for renewables (as amended)
Great British Energy is an independent guide. We are not affiliated with Great British Energy, the publicly owned energy company (gbe.gov.uk), HM Government, Ofgem or OZEV. Scheme rules and budgets change, so confirm the current position with the scheme administrator before you commit spend. We may receive a fee from the installer we introduce you to.