How much do commercial solar panels cost in the UK?
UK commercial solar capex ran from £540/kWp on a 1MW+ ground-mount to £1,100/kWp on a 50kW rooftop in our last 30 quoted projects. After Full Expensing or a grant, most £150k+ projects pay back in under five years. This page sets out current prices, the full cost stack and how grants change the maths.
Commercial solar costs by system size
Installed cost ranges below are based on our last six months of UK projects (Q4 2025–Q2 2026). They include a turnkey scope: design, DNO, install, commissioning and insurance-backed warranty. They exclude battery storage and EV charging, which are priced separately.
| System size | Total capex | £/kWp | Annual yield | Pre-grant payback | Post-grant / FE |
|---|---|---|---|---|---|
| 50 kWp Small office, agricultural barn, retail unit | £42,500 – £55,000 | £850 – £1,100 | ~47,500 kWh/year | 6.5–8 years | 5–6.5 years (with Full Expensing) |
| 100 kWp Medium SME, small school, hotel | £75,000 – £95,000 | £750 – £950 | ~95,000 kWh/year | 6–7.5 years | 4.5–6 years (with Full Expensing) |
| 250 kWp Mid-sized factory, large school, hospital ward | £165,000 – £210,000 | £660 – £840 | ~237,500 kWh/year | 5.5–7 years | 4–5.5 years |
| 500 kWp Large factory, multi-academy trust, NHS site | £295,000 – £380,000 | £590 – £760 | ~475,000 kWh/year | 5–6.5 years | 3.5–5 years (with grant) |
| 1 MW (1,000 kWp) Major industrial, large NHS trust, distribution centre | £540,000 – £720,000 | £540 – £720 | ~950,000 kWh/year | 4.5–6 years | 3–4.5 years (with IETF grant) |
| 2 MW (2,000 kWp) Heavy industry, large logistics hub, ground-mount | £1.05m – £1.40m | £525 – £700 | ~1,900,000 kWh/year | 4.5–6 years | 3–4.5 years |
Pricing reflects new-build commercial PV with single-phase or three-phase inverters as appropriate. Ground-mount projects above 500kW use central inverters and trended to the lower end of the range. Half-hourly self-consumption rates assume daytime industrial or commercial load profiles.
Where the money actually goes — full cost stack
The £/kWp number masks ten distinct cost lines. Understanding the stack matters because the only line that has fallen materially in the last 18 months is panels (down 22%) — most other costs have held or risen.
How grants and tax allowances change the maths
The headline grant percentages — 30% IETF, 100% PSDS, 40% REPF — are real but they apply to eligible capex, not total capex. Eligible capex usually excludes contingency, certain fees and any element of "betterment" (e.g. roof replacement). The effective grant rate, on average, is 18–24% of total project capex on IETF, 75–85% on PSDS once ineligible items are stripped, and 25–32% on REPF.
Full Expensing is the simplest. For any UK incorporated company paying the main rate of corporation tax (25%), £1 of solar capex saves you 25p of tax in the period the spend is incurred. So a £400,000 system effectively costs you £300,000 net. Stacked on a grant, it applies to the after-grant capex — so an IETF grant covering 30% leaves £280,000 net of grant, which Full Expensing then reduces to £210,000 effective net cost. Full mechanics here.
The cost lines installers usually under-quote
DNO connection costs. For systems over 16A per phase (4kW single-phase, 12kW three-phase), connection requires a G99 application to the DNO (UK Power Networks, National Grid Electricity Distribution, SP Energy Networks, etc.). Anything above 100kW often triggers non-contestable works — switchgear upgrades, transformer changes, network reinforcement — that the DNO charges directly. We have seen these come in anywhere from £8,000 to £180,000. They should always be quoted before contracts.
Structural reinforcement. Buildings constructed pre-2000 — especially clad steel-portal warehouses — often need additional purlins or bracing to take a 12–15kg/m² PV load. A structural engineer's report (£600–£1,200) up-front saves the surprise cost later.
Roof remediation. Solar PV is a 30-year asset; the roof should match. Expect to budget for re-coating or panel replacement on roofs more than 15 years old. PSDS allows a portion of remediation cost to be claimed; private sector grants usually do not.
Battery sizing changes the model. Adding a 100kWh battery to a 250kWp PV system typically lifts capex by £40,000–£55,000 but raises self-consumption from 75% to 92%, which materially shortens payback on most commercial sites with non-24h operation.
How to validate a quote
The three checks that catch 90% of overpriced quotes: (1) panel + inverter cost together should be no more than 50–55% of total quote — anything higher is over-marked-up; (2) DNO costs should be a separate line, not buried in "civils" — if it isn't, ask for the G99 confirmation letter; (3) IWA insurance-backed warranty should be itemised — its presence is the cheapest signal that the installer is in an MCS-aligned scheme.
If you want a second opinion on a quote, we benchmark commercial solar quotes for free — no commitment, no upsell. The funding review form includes a quote review option.
Cost FAQs
How much do commercial solar panels cost per kWp in 2026?
What does that cost cover?
How much can grants reduce the capex?
What's the typical payback period?
Are panel prices going up or down in 2026?
Are there any hidden costs?
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