Commercial solar panels for UK businesses
If your business owns or leases roof space and burns most of its electricity between 8am and 5pm, rooftop solar is one of the few capital projects that pays for itself and then keeps going for another two decades. This page covers the numbers that actually decide it — roof area, generation, indicative cost and payback — without the brochure language.
The four numbers that matter
What counts as a commercial panel
There is no separate 'commercial' panel — the difference is scale and specification. Commercial roofs typically take 550–700 W bifacial or mono-PERC modules on trapezoidal or membrane fixings, wired into three-phase string inverters rather than a single small domestic unit.
How much roof you need
Allow roughly 6–8 m² of usable roof per kWp once walkways, plant, rooflights and set-backs are deducted. A 40,000 sq ft warehouse roof commonly supports 250–400 kWp, depending on purlin spacing and remaining roof life.
What it generates
UK commercial rooftops usually yield around 850–1,000 kWh per kWp per year. Orientation, pitch and shading move that figure more than panel brand does, which is why a site-specific model beats a brochure comparison.
What it costs
Installed cost is indicatively £600–£900 per kWp, falling per kWp as the array grows. Scaffolding, roof condition, DNO works and switchroom distance are the variables that move a quote most.
All figures are indicative UK ranges. Every project needs a site-specific review before any saving, price or payback is relied on.
Browse by system size
Each size page sets out typical roof area, panel count, annual generation and indicative cost, so you can sanity-check a quote before you sign anything.
- 50 kWp
50 kWp commercial solar system — cost, size and payback (UK)
£40,000–£50,000 installed · Payback 4–6 years after Full Expensing
- 100 kWp
100 kWp commercial solar system — cost, size and payback (UK)
£75,000–£90,000 installed · Payback 3.5–5 years after Full Expensing
- 150 kWp
150 kWp commercial solar system — cost, size and payback (UK)
£115,000–£135,000 installed · Payback 3.5–5 years after Full Expensing
- 250 kWp
250 kWp commercial solar system — cost, size and payback (UK)
£180,000–£220,000 installed · Payback 3.5–5 years after Full Expensing
- 500 kWp
500 kWp commercial solar system — cost, size and payback (UK)
£360,000–£420,000 installed · Payback 3.5–4.5 years after Full Expensing
- 1 MWp
1 MWp commercial solar system — cost, size and payback (UK)
£700,000–£860,000 installed · Payback 3.5–4.5 years after Full Expensing
- Battery + solar
Battery storage sizing for commercial solar (UK)
£250–£450 per kWh installed (£25k–£45k per 100 kWh) · Payback 6–9 years standalone; 5–7 years paired with new solar
- Sizing calculator
Commercial solar system size calculator (UK)
£700–£950/kWp installed · Payback 3.5–6 years typical
Where to read further
FAQ
How many commercial solar panels do I need?
Work backwards from your daytime electricity use rather than your roof. A site consuming 250,000 kWh a year with steady weekday load typically suits 150–250 kWp, which is roughly 270–450 modern panels. Our calculator sizes it in about a minute.
Which commercial solar panels are best?
Tier-1 manufacturers with UK-serviceable warranty routes and a bankable balance sheet matter more than a headline efficiency figure. Panel choice usually changes yield by a few per cent; design and self-consumption change payback by years.
Do commercial solar panels need planning permission?
Most rooftop arrays in England fall under permitted development, but listed buildings, conservation areas, some scale thresholds and ground-mounted schemes are exceptions. A site-specific check is quick and worth doing early.
How long do commercial solar panels last?
Panels normally carry 25–30 year performance warranties and keep producing beyond that at reduced output. Inverters are the shorter-lived component, typically 10–12 years with extensions available.
Can I install commercial solar panels without capital?
Yes. Asset finance, lease and PPA structures all exist for UK commercial solar. Buying outright gives the highest lifetime return; a PPA gives day-one savings with no capex.