Cost
What does commercial solar cost per kW in the UK?
Commercial solar in the UK costs £900-£1,200 per kW for systems under 100 kW, £750-£950/kW for 100-500 kW systems, and £700-£850/kW above 500 kW. The figure includes panels, inverters, mounting, install, DNO connection, and a 10-year workmanship warranty — but excludes battery storage and any structural or three-phase upgrades.
Commercial solar PV in the UK costs £900-£1,200 per kW for sub-100 kW systems, dropping to £750-£950/kW between 100 and 500 kW, and £700-£850/kW above 500 kW. These are 2026 turnkey rates that include panels, inverters, mounting, AC/DC cabling, scaffolding, structural survey, DNO application, MCS commissioning, building control, and a 10-year insurance-backed workmanship warranty. They exclude VAT (20% standard rate applies), battery storage, three-phase upgrades, and any structural reinforcement.
Why £/kW falls as systems get bigger
Most of the fixed costs in a commercial solar install don’t scale with system size. The DNO application, scaffolding mobilisation, inverter sizing thresholds, MCS commissioning, building control sign-off, and project management all cost roughly the same whether you install 30 kW or 130 kW. Spread those fixed costs over more kW and the per-kW price falls.
Per-kW price bands explained
Below 50 kW: £1,000-£1,300/kW
Small installs. Often roof-edge access constraints, single inverter, low-volume materials buy. Typical project: a 30 kW system on a 4-bay office at £36,000.
50-100 kW: £900-£1,100/kW
The “sweet spot” for SME installs. G98 application (4-8 weeks DNO timescale), one or two inverters, scaffolding amortised. Typical project: a 75 kW system on a marketing agency at £71,000.
100-500 kW: £750-£950/kW
Larger sites. G99 application now required (6-18 months DNO timescale). Typical project: a 250 kW install on a light-industrial unit at £200,000.
500 kW+: £700-£850/kW
Industrial scale. Often two-stage DNO process, custom switchgear, transformer upgrades possible. Typical project: a 750 kW system on a logistics warehouse at £575,000.
What’s not in the £/kW figure
| Add-on | Cost |
|---|---|
| Battery storage (DC-coupled) | £450-£700/kWh of usable capacity |
| Three-phase supply upgrade | £2,500-£8,000 (DNO charge plus internal works) |
| Power optimisers | £80-£120 per panel premium over string inverter |
| Asbestos management plan | £5,000-£20,000 depending on roof condition |
| Roof structural reinforcement | £8,000-£40,000 if calcs fail |
| DNO connection charge (large G99) | £15,000-£250,000+ on constrained networks |
If your installer’s quote doesn’t break these out, ask them to. The headline £/kW figure is a useful comparison tool but only for like-for-like specs.
A cowboy warning
Some installers quote sub-£700/kW figures by stripping the spec — Tier 2 panels, basic string inverters, single-phase only, no optimisers, minimal warranty. The panels work; the install just won’t last. Genuine 25-year output warranties from Tier 1 manufacturers (Trina, JA Solar, Longi, REC, Jinko) and fully type-tested inverters (SolarEdge, Fronius, SMA, Huawei) sit at the figures above.
Common misconceptions
A persistent myth: that £/kW will halve in the next two years. Module prices have come down steadily since 2010 but UK labour, scaffolding, copper cabling, and DNO charges have been climbing. Net installed cost per kW has been roughly flat for three years.
Another: that 20% VAT will be removed for commercial solar. The zero-rated VAT relief introduced in 2022 applies only to domestic installations. Commercial PV remains standard-rated. Don’t price an install assuming a VAT cut that hasn’t happened.
Next steps
For a like-for-like quote based on your meter data and roof drawings, request a free feasibility study. For broader cost context see our cost page and the grants and funding summary. Related: total install cost, 100 kW system cost.
Related questions
How much does a 100 kW commercial solar system cost?
A 100 kW commercial solar system in the UK costs £85,000-£110,000 turnkey in 2026, depending on roof type, three-phase status, and whether optimisers are specified. Typical annual generation is 90,000-95,000 kWh, saving £20,000-£25,000/year for a daytime-occupied SME at current grid prices. Simple payback lands at 4-5 years before tax relief, 3-4 years after AIA.
How much do commercial solar panels cost in the UK?
A typical UK SME install ranges from £20,000 (small office, ~25 kW) to £270,000 (light industrial, ~300 kW). Cost per kW is £900-£1,200 below 100 kW, falling to £700-£850/kW above 500 kW. After 100% AIA tax relief, effective net cost for limited companies is roughly 75% of headline price.
What is the cost per kWp for commercial solar in the UK?
Cost per kWp (kilowatt-peak) for UK commercial solar in 2026 ranges from £900-£1,200 below 100 kWp to £700-£850 above 500 kWp. kWp is the rated DC capacity at standard test conditions, not the AC output your meter sees. AC output is typically 5-10% lower than DC capacity due to inverter clipping and system losses.