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.