How Much Does a 250 kW Factory Solar System Cost? (UK 2026)
A 250 kW factory solar system costs £175,000–£212,500 fully installed in 2026. That’s £700–£850 per kWp. Year-1 saving: £55,000–£75,000. Payback: 3–3.5 years. Suits medium factory, bakery, plastics moulder, automotive Tier-2 sites drawing 700–1,200 MWh/year.
60-second answer
A 250 kW commercial solar PV system in the UK costs £175,000–£212,500 fully installed in 2026. That includes panels, inverters, mounting, structural survey, DNO G99 connection, MCS commercial certification, IWA insurance-backed warranty and commissioning.
- Cost per kWp installed: £700–£850
- Number of panels: 460 (at 545–625 W each)
- Roof area required: ~1,500 sqm of unobstructed roof
- Annual generation: ~230,000 kWh
- Year-1 saving: £55,000–£75,000 (against current Q1 2026 grid rate of 27.69 p/kWh)
- Simple payback: 3–3.5 years on capital purchase
- Tax treatment: 100% AIA in year 1 covers up to £1m of capex — effective post-tax cost £131,250–£159,375
What’s included in the 250kW price
Every line item that goes into the fully-installed price for a UK commercial solar system this size:
- Panels (Tier-1 TOPCon n-type, e.g. Jinko Tiger Neo 580W or Trina Vertex 605W) — 35–42% of total cost
- Inverters (Sungrow / Huawei / SMA / Fronius) — 12–15%
- Mounting and rails (clamp-fix on standing seam, rail-mount on profiled metal, ballasted on flat) — 8–12%
- DC and AC cabling, isolators, combiners — 5–7%
- Labour and project management — 12–18%
- Scaffolding and access — 3–6%
- Structural survey, electrical design, PVSyst yield modelling — 3–5%
- DNO G99 connection (application fee, study, connection works) — 4–8%
- MCS commissioning, IWA warranty, commissioning certificate — 2–4%
The lower end of the price range applies to easy installs — standing seam metal roof, three-phase supply already in place, no grid reinforcement needed. The upper end applies where any of: roof refurbishment is required, single-phase supply needs upgrading, scaffolding is complex, or DNO grid reinforcement adds £15–£75k.
How a 250kW factory solar system pays back
For a typical UK factory operating Mon–Fri 8am–6pm with the load profile that matches a 250 kW system, the simple payback runs 3–3.5 years on capital purchase. Here’s the math:
- Capex: ~£193,750 fully installed
- Annual self-consumption saving: ~£65,000 year 1, escalating ~3% per year against grid
- SEG export income: ~£6,500/year on the 12–25% of generation that exports
- O&M cost: £8–£12 per kW per year — for 250 kW that’s ~£2,500/year
- AIA tax relief: 100% of capex deductible year 1 — saves ~£48,437 in cash tax at 25% corporation tax
- 25-year cumulative saving (NPV @ 7%): roughly 4–5x the initial capex
IRR over 25 years for a 250 kW install lands at 18–28% — well above any board’s hurdle rate. The system runs for 30–35 years with one inverter replacement at year 12–15.
Financing routes for this size
For a £175,000–£212,500 install, the four mainstream financing routes:
- Capital purchase + AIA — pay £175,000–£212,500 cash, claim 100% first-year tax relief. Best NPV. Ties up capex.
- Asset finance / lease-to-own — spread cost over 5–15 years at 5–8% interest. Cash-flow positive from month 1 at most sites of this size. Take ownership at term-end.
- PPA (Power Purchase Agreement) — third party owns and operates the 250 kW system, you buy the kWh at 15–30% below grid for 15–25 years. Zero capex, lower 25-year value but no upfront cash.
- Green business loan — 100% finance at 4–8% interest, 5–15 years. You own the asset immediately. Loan repayments typically below energy savings from month 1.
See our full factory solar financing guide for side-by-side modelling.
250kW factory solar — FAQs
How much roof do I need for a 250 kW solar PV system?
About 1,500 sqm of unobstructed roof for portrait-mounted high-power panels. Slightly more if the roof has chimneys, AHUs, parapets or shading, slightly less for east-west bifacial layouts on flat membrane roofs.
How many solar panels in a 250 kW system?
460 panels in 2026 (using 545–625W TOPCon n-type modules). The exact count depends on panel wattage selected, roof orientation, and whether you use bifacial or monofacial.
How long does a 250 kW install take?
2–5 days physical install for 250 kW, plus DNO connection (final 4–8 hour outage scheduled at weekend or shutdown). Total project from contract to commissioned: 8–14 weeks (the long pole is G99 grid connection, 6–18 months DNO timeline, which we initiate before contract).
Will a 250 kW system cover my factory’s full electricity demand?
For a factory drawing 700–1,200 MWh/year, a 250 kW system typically offsets 40–65% of annual demand. To get to 100% renewable, combine with a green PPA on a remote solar farm or with a green energy supplier.
Can I get a 250 kW solar PV system on PPA with no capex?
Yes — multiple UK PPA providers operate at this size. Standard form: 15–25 year contract at 12–18 p/kWh fixed, with annual escalation tied to RPI or fixed at 1–2%. Day-one positive cash flow vs current 27.69 p/kWh grid retail.
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