Cost & payback · Updated May 2026

Commercial solar panel cost UK 2026 (after grants and tax relief)

Honest 2026 maths on commercial solar — capex by system size, post-tax effective cost, SEG export revenue, and payback under three real-world scenarios. No installer puffery, no inflated savings projections.

Capex by system size (2026 prices)

UK commercial solar PV prices have stabilised in 2026 after the volatility of 2022-2024. Tier 1 panel pricing is around £0.18/Wp landed; inverter pricing around £0.07/Wp; mounting and BOS around £0.18/Wp; installation and DNO around £0.15-£0.30/Wp depending on roof type. The summary below shows typical 2026 installed costs.

System size	Capex (excl. VAT)	£/Wp	Annual generation (UK average)	System type
10 kWp	£11,500 – £14,000	£1.15 – £1.40	9,500 kWh	Office / small retail
30 kWp	£30,000 – £36,000	£1.00 – £1.20	28,500 kWh	Small hotel / restaurant
50 kWp	£42,500 – £52,500	£0.85 – £1.05	47,500 kWh	Small factory / farm
100 kWp	£80,000 – £100,000	£0.80 – £1.00	95,000 kWh	Medium factory / hotel
250 kWp	£175,000 – £215,000	£0.70 – £0.86	237,500 kWh	Large hotel / supermarket
500 kWp	£325,000 – £400,000	£0.65 – £0.80	475,000 kWh	Warehouse / factory
1 MWp	£600,000 – £750,000	£0.60 – £0.75	950,000 kWh	Large warehouse / industrial
2.5 MWp	£1.4m – £1.9m	£0.56 – £0.76	2.4m kWh	Big-box logistics / solar farm

Prices are indicative — actual quotes vary by roof type (pitched/flat/asbestos), DNO connection complexity, structural strengthening needs, mounting system (rail/ballast), inverter brand and battery integration. Always obtain 3 quotes from MCS-accredited installers.

Post-tax effective cost

UK limited companies can deduct 100% of qualifying solar capex from corporation tax in year one under Full Expensing. At the 25% main rate, that's 25p saved per £1 spent. Sole traders, partnerships and LLPs use the AIA instead — identical 100% deduction up to a £1m annual cap.

Worked example: 100kWp install for a limited company

• Installation cost: £90,000 (excl. VAT — reclaimable)
• Full Expensing year-one deduction: £90,000
• Corporation tax saved at 25%: £22,500
• Effective net cost: £67,500
• SEG revenue (1p export tariff baseline, 35% export): ~£330/year
• SEG revenue (15p best fixed tariff, 35% export): ~£5,000/year
• Self-consumption saving (60%, 28p import): ~£15,960/year
• Post-tax payback: 4.0-4.5 years

Payback under three scenarios

The maths varies materially depending on import tariff, export tariff, self-consumption percentage and finance route. Three honest scenarios:

Scenario A — Office, daytime occupancy, high self-consumption

• System: 50 kWp, £45,000 capex
• Self-consumption: 75% (daytime load)
• Import rate: 28p/kWh (commercial fixed)
• Year-one savings: £9,975 self-consumption + £590 SEG = £10,565
• Post-FYA effective cost: £33,750
• Payback: 3.2 years

Scenario B — Warehouse, low self-consumption, big export

• System: 500 kWp, £350,000 capex
• Self-consumption: 25%
• Import rate: 22p/kWh
• Year-one savings: £26,125 self-consumption + £8,910 SEG (5p) = £35,035
• Post-FYA effective cost: £262,500
• Payback: 7.5 years

Scenario C — Hotel with pool, mixed load

• System: 150 kWp, £127,500 capex
• Self-consumption: 65%
• Import rate: 31p/kWh (hospitality commercial)
• Year-one savings: £28,729 self-consumption + £1,995 SEG = £30,724
• Post-FYA effective cost: £95,625
• Payback: 3.1 years

Hidden costs to watch for

• Roof refurbishment if existing roof is end-of-life — typically £80,000-£300,000 added cost for a typical warehouse
• Asbestos cement removal — £15,000-£40,000 for a smaller commercial roof, more for larger
• Structural assessment (Cat 2 survey) — £2,500-£8,000 typically required for older portal frames
• DNO connection upgrades — £8,000-£250,000 depending on local network capacity
• Three-phase upgrade where only single-phase exists — £8,000-£30,000
• Battery storage if pursued — £400-£700/kWh installed
• Insurance premium adjustment — typically £150-£800/year additional

FAQs

Cost & payback FAQs

How much do commercial solar panels cost in 2026?

Installed commercial solar PV in the UK costs approximately £0.80-£1.05/Wp in 2026, depending on system size, roof type, mounting requirements and DNO connection. A 100kWp system is typically £80,000-£105,000 installed (excl. VAT). After 100% Full Expensing for limited companies, net cost falls to around £60,000-£79,000.

What is the payback for commercial solar after grants?

Typical post-tax payback for a UK commercial solar installation in 2026 is 4-6 years for limited companies using Full Expensing, 5-7 years for partnerships using AIA, and 3-5 years where regional capital grants apply. Internal Rate of Return over 25 years is 12-22%.

Does the system size affect £/Wp?

Yes — economies of scale matter. Small systems (10-30kWp) typically £1.15-£1.40/Wp. Medium (50-150kWp): £0.85-£1.05/Wp. Large (250-1000kWp): £0.65-£0.85/Wp. Above 1MWp: £0.55-£0.75/Wp.

What's included in a commercial solar quote?

A complete commercial solar PV quote should cover: panels (typically Tier 1 — JA Solar, Trina, LONGi, Canadian Solar, Jinko), inverters (SolarEdge, Huawei, SMA, Sungrow), DC and AC cabling, mounting (rail-based or ballasted), DC isolators, AC isolators, monitoring, MCS certification, DNO G99 application, commissioning, and 25-year panel warranty / 10-year workmanship warranty.

How does battery storage affect cost?

Lithium-ion battery storage adds £400-£700/kWh installed in 2026. For a 100kWh battery on a 200kWp commercial system, expect £45,000-£70,000 additional capex. Battery storage usually adds 1-3 percentage points to IRR when correctly sized for the load profile.

What's the difference between £/Wp and £/kWp pricing?

Wp (watt-peak) and kWp (kilowatt-peak) are the same unit at different scales. 1 kWp = 1,000 Wp. A system priced at £1.00/Wp is the same as £1,000/kWp. Most UK commercial quotes use £/Wp for clarity; manufacturers' price lists use £/kWp.