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Commercial Solar Finance UK · Independent
Cost Guide · 500kW

How much does a 500kW commercial solar system cost in 2026?

500kWp commercial solar is large-format infrastructure — properly engineered DNO connection, structural assessment of the full roof, project-management overhead suited to a multi-month build. Per-Wp hardware costs fall into the deepest volume tier, and project economics genuinely start to compete with CapEx-prioritised investment alternatives. Most 500kWp projects sit £360k–£450k turnkey in 2026.

Capex range

£360,000–£450,000

£/kWp

£720–£900

Annual yield

475 MWh

Payback (post-FYA)

2.8–4 years

Cost breakdown — where the money goes on a 500kW project

L01 · 50–55%

Hardware (modules, inverters, mounting)

£200k–£245k

Deepest volume tier — typically £0.42–£0.50/Wp on hardware. Central inverter architecture often used at this scale.

L02 · 16–18%

Installation labour (M&E, roof access)

£60k–£80k

Multi-week project with 6–10 crew. Specific scaffold and edge-protection requirements at scale. Substantial mechanical handling for module distribution.

L03 · 11–13%

Soft costs (DNO, structural, design)

£40k–£60k

G99 connection often triggers reinforcement studies above 200kW. AVR studies for sites with existing transformer capacity. Full structural and wind-uplift assessment.

L04 · 4–5%

Commissioning & certification

£15k–£22k

G99 commissioning with full DNO inspection. Substantial as-built documentation, monitoring portal setup.

L05 · 13–15%

Margin and contingency

£45k–£65k

Margin compresses at scale (8–12% typical) but contingency stays at 5%. Project complexity rewards transparent line-item pricing.

Worked example: 500kW commercial solar at central pricing

Capex (central)

£405,000

Year-1 corp tax saved

£50,625 corp tax saved (50% FYA × 25%)

Year-1 electricity saving

£100k (475MWh × ~21p blended)

Year-1 net cash

-£254k (after capex, FYA, savings)

25-year lifetime IRR

15–20%

Simple payback

3.5–5 years

Run your own numbers in our interactive calculator →

Best fit

Profitable large manufacturers with daytime-heavy demand, distribution operators with continuous lighting/refrigeration loads, NHS trusts pursuing PSDS bundled applications, MATs with portfolio applications across school estate.

Best for

A 500kW system suits large manufacturer, mid-sized distribution warehouse, NHS hospital estate, multi-school MAT portfolio, university faculty building, large hospitality estate.

Not suitable

Sites with under 200kVA existing capacity that would require £25k+ DNO reinforcement before connection. Buildings with sub-65% daytime self-consumption potential (size down to 300kWp).

Other system sizes

100kW system cost

£850–£1,100 per kWp

200kW system cost

£800–£1,000 per kWp

1MW system cost

£700–£900 per kWp

500kW cost FAQs

What DNO challenges typically arise at 500kW?
G99 connection at 500kW frequently triggers DNO reinforcement studies — particularly on industrial estates with existing constrained capacity. Studies range £2k–£8k for desk study, £10k–£60k for any actual reinforcement work (transformer upgrade, AVR fitting, network upgrade). Lead time can extend 12–24 weeks DNO-side. We resolve DNO position before sizing finalisation, often recommending sizing to existing connection capacity rather than triggering reinforcement.
Is AIA still worth claiming at 500kW?
Absolutely — £405k qualifying capex sits inside the £1m AIA cap. AIA delivers £101k year-one tax relief (25% × £405k), beating FYA + special-rate-pool route. The AIA route only stops being optimal when total qualifying capex for the period exceeds £1m. Confirm AIA headroom with your accountant first.
How does battery storage change the 500kW economics?
For sites with significant time-of-use tariff exposure or limited export consent, a 500kWp + 250kWh battery pairing can lift project IRR by 2–4 percentage points versus solar-only. Battery capex adds £100k–£150k. The case is strongest on continuous-operation industrial sites with tariff-sensitive demand spikes or DNO-export-constrained connections.
What's a realistic build timeline for 500kW?
20–28 weeks from contract execution to commissioning is typical. Breakdown: 6–10 weeks DNO + structural + design (sometimes parallel with procurement), 12–16 weeks procurement (modules typically have 8–12 week lead), 4–6 weeks installation (multi-shift crews on accessible sites), 2–4 weeks commissioning. Year-end FYA timing requires placing the order by July for end-March commissioning.

Get a comparable 500kW cost benchmark for your specific site

Send postcode, roof area, and annual electricity consumption. We return an indicative capex range plus the after-tax model across all six finance structures, sized for 500kW.

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