UK commercial solar - quick answers
Short, cited answers to the most common questions UK businesses ask about commercial solar.
How much do commercial solar panels cost in the UK?
In 2026, commercial solar panels in the UK cost £700–£950 per kWp installed for standard rooftop systems. A 50 kWp system typically costs £40,000–£50,000; a 250 kWp system £180,000–£220,000; and a 1 MWp system £700,000–£860,000. Full Expensing reduces the effective cost by 25% for limited companies.
How long does commercial solar installation take?
A UK commercial solar installation takes 2–12 weeks on-site depending on system size. Including DNO G99 approval, structural survey and commissioning, the full project timeline from signed order to first generation is typically 3–6 months. A 100 kWp rooftop system takes about 3–4 weeks on-site; a 1 MWp system takes 8–12 weeks.
Is commercial solar worth it in 2026?
Yes - commercial solar is worth it for most UK businesses in 2026. Typical rooftop systems pay back in 3.5–6 years and deliver a 15–25% internal rate of return (IRR) over a 25-year asset life. High grid prices, 100% Full Expensing on qualifying capex, and the tightening MEES/EPC B requirement by 2030 all strengthen the case versus 2022.
What size solar system does my business need?
Size a commercial solar system to match your daytime electricity demand, not your total annual bill. A good starting rule: 1 kWp of solar per 1,000 kWh of annual daytime consumption. A business using 250,000 kWh/year with 60% daytime demand needs roughly 150 kWp - enough to cover most on-site load without heavy export.
Do you need planning permission for commercial solar in the UK?
Most rooftop commercial solar in England is Permitted Development up to 1 MWp and does not need planning permission. Panels must sit no more than 200 mm above the roof plane and the building must not be listed or in a conservation area. Ground-mounted arrays above 9 m² and any array on a listed or heritage building always need a planning application.
How much can a business save with solar panels?
UK businesses save £180–£240 per installed kWp per year with commercial solar in 2026, based on 70% self-consumption at 24–28p/kWh and 30% export at 5–8p/kWh. A 100 kWp system saves £18,000–£24,000 per year; a 500 kWp system saves £90,000–£120,000; and a 1 MWp system saves £180,000–£240,000.
What grants are available for business solar in the UK?
There is no single national grant for UK commercial solar in 2026, but businesses can access substantial support: 100% Full Expensing (25% corporation tax saving), the Salix public-sector loan scheme (interest-free for schools, NHS and councils), the Industrial Energy Transformation Fund (IETF) for manufacturers, and regional decarbonisation schemes from Growth Hubs and Combined Authorities.
How many solar panels fit on a warehouse roof?
A modern UK warehouse fits roughly 100 kWp - around 200 solar panels at 500 W each - per 1,000 m² (10,760 sq ft) of usable south-facing metal roof. A 40,000 sq ft distribution shed typically fits a 300 kWp array (~600 panels); a 150,000 sq ft big-box DC fits about 1.1 MWp (~2,200 panels) after allowing for walkways, rooflights and setbacks.
Can a business sell solar electricity back to the grid?
Yes - UK businesses can sell surplus solar electricity to the grid under the Smart Export Guarantee (SEG). Every licensed electricity supplier over 150,000 customers must offer an SEG export tariff. In 2026, tariffs typically pay 5p–15p per kWh exported. Larger sites (500 kWp+) can also enter Power Purchase Agreements or flexibility markets for higher returns.
What is the payback period for commercial solar in the UK?
The payback period for UK commercial solar in 2026 is 3.5–6 years for well-sized systems on high-consumption sites, calculated after 100% Full Expensing. Larger systems (500 kWp+) on 24/7 sites often pay back in under 4 years; smaller systems on part-time premises take 6–8 years. The 25-year IRR sits at 15–25% for most projects.
Can I install solar panels on a leased commercial building?
Yes - solar can be installed on a leased UK commercial building, provided the landlord gives written consent, usually through a licence for alterations plus a roof licence or lease variation. The three normal routes are tenant-funded, landlord-funded with cost recovery, or a third-party PPA. A remaining lease term of at least seven years makes a tenant-funded system far easier to justify.
What happens if my solar export is limited?
An export limit caps how much electricity you may send back to the grid, and on constrained networks it can be set to zero. It does not stop a project. The system is designed around on-site self-consumption instead, with an export limitation device holding the inverters within the agreed limit. Because on-site electricity is worth more than export payments, most business cases change very little.
Will a solar installation disrupt my business?
For most commercial sites, very little. The bulk of the work happens on the roof, away from operations, and is sequenced with your team. The one moment that touches the building is the electrical tie-in and commissioning, which needs a planned shutdown of the board being connected - typically a few hours, and normally booked for an evening, weekend or shutdown week.
Can a business claim tax relief on solar panels?
In most cases, yes. Solar PV is generally treated as plant and machinery in the special rate pool, so a UK company buying outright can usually claim Full Expensing or use the Annual Investment Allowance, with the 50% First-Year Allowance as the alternative route. Hire purchase normally still qualifies; an operating lease or PPA does not, because you do not own the asset.
Is VAT charged on commercial solar panels?
Yes. Commercial solar installations are charged VAT at the standard 20% rate - the zero rate available on some domestic work does not extend to business premises. If you are VAT-registered and the system serves taxable business activity, the VAT is normally recoverable as input tax, making it a cashflow item rather than an added cost.
Does solar improve an EPC rating and MEES compliance?
Usually yes. Solar reduces the building's modelled energy use, which is what a commercial EPC measures, so it often moves a property up a band. That matters most where a building sits below the MEES minimum of E and cannot be let or renewed. The improvement must be captured in a reassessment after commissioning to count.
Does solar increase commercial property value?
An owned solar system supports value in two ways: it lowers the building's running costs and it usually improves the EPC rating, which matters for MEES lettability and for tenants screening on energy performance. Valuers treat it as one factor among many rather than a set uplift, so the honest position is a stronger letting and resale case, not a guaranteed percentage.