Ground-Mounted Solar Panels for UK Factories — 2026 Guide
Ground-mounted solar PV for UK factory sites with adjacent land. System sizes, planning, capex per kW, payback — vs rooftop comparison.
When ground-mounted beats rooftop
Ground-mounted solar PV makes sense for UK factory sites with three characteristics: (1) adjacent owned or leasable land — typically rural manufacturing, food production, or distribution sites with paddocks, undeveloped land or under-used yard space; (2) roof unsuitable for retrofit — asbestos cement, listed building, or structurally compromised; (3) scale ambition above ~2 MW — ground-mount systems can scale to 5 MW+ with land area, where rooftops are usually capped by available area.
For 80% of UK factories on industrial estates, rooftop wins on planning, land use, and capex efficiency. Ground-mount becomes interesting at the edges — we model both routes for any client whose site has > 0.25 acres of land per 200 kW of intended PV.
Ground-mount vs rooftop — side-by-side
| Factor | Rooftop | Ground-mount |
|---|---|---|
| Capex per kW (turnkey) | £700–£900 | £800–£1,100 |
| Land use | Existing roof | ~3 acres per 1 MW |
| Planning route | Permitted Development | Full planning + landscape impact |
| Annual yield | ~950 kWh/kWp | ~1,050 kWh/kWp (optimal tilt) |
| G99 connection | Often via existing connection | Often new G99 connection required |
| Best for | 80% of UK factories | Land-rich rural sites, > 1 MW scale |
Real example: 1.8 MW ground-mount on a Norfolk food production site
A frozen vegetable processor in Norfolk has 9 acres of unused land adjacent to the main factory building. Demand profile: 24/7 refrigeration baseload, 6,800 MWh/year. We modelled both routes:
- Rooftop only: 850 kW maximum on the available 4,200 sqm of clear roof. Covers 32% of annual demand.
- Ground-mount only: 1.8 MW on 5.5 acres. Covers 64% of annual demand. Capex £1.6m.
- Combined: 850 kW roof + 1.5 MW ground = 2.35 MW. Covers 78% of annual demand. Capex £1.95m.
Client chose the combined route. Payback 4.2 years on capital purchase, 100% AIA on the first £1m + 50% FYA on the balance.
Rooftop vs ground-mount — whole-life cost comparison
The headline capex gap is modest, but the real decision turns on land availability, planning route and connection cost. A roof you already own carries no land cost and usually no landscape-impact planning burden, which is why it beats ground-mount on almost every industrial-estate site. Ground-mount wins back ground through higher per-kWp yield (optimal 30°–35° south tilt vs the fixed pitch of an existing roof) and the ability to scale beyond what the roof footprint allows.
| Cost factor | Rooftop (existing roof) | Ground-mount |
|---|---|---|
| Turnkey capex per kWp | £700–£900 | £800–£1,100 (incl. frames, groundworks, cabling runs) |
| Land needed per MWp | ~6,500–8,000 sqm of roof | ~2.5–3 acres of cleared ground |
| Planning route | Usually permitted development | Full planning application (landscape & visual impact) |
| Typical annual yield | ~950 kWh/kWp | ~1,050 kWh/kWp at optimal tilt |
| Civils & cabling cost | Low — uses existing risers | Higher — trenched DC/AC runs to the factory |
| Indicative payback (self-consumption) | 3–5 years | 4–6 years (longer if new G99 + access track needed) |
| Best for | 80% of UK factories on industrial estates | Land-rich rural sites, unsuitable roofs, >1 MW scale |
Capital allowances apply identically to both: the structural ground-mount frame and the PV system qualify for the Annual Investment Allowance (100% on the first £1m of qualifying spend), with the balance attracting the 50% first-year allowance. We model rooftop, ground-mount and combined routes against your actual half-hourly meter data before recommending a route.
Permitted development vs full planning for ground-mount
This is the single biggest difference between the two routes. Rooftop solar on a factory is in most cases permitted development (PD) under Class J of the General Permitted Development Order — no planning application, provided the panels sit within set height and edge limits and the building is not listed or in a conservation area. Ground-mounted arrays are a different category entirely.
Free-standing ground-mount solar has a narrow PD allowance: a single installation is permitted only up to 9 sqm of array area and 4 m in height on industrial land — far too small for any factory-scale system. Anything meaningful (a 250 kW array upwards) therefore needs a full planning application to the local authority, assessed on landscape and visual impact, glint and glare to roads or aviation, drainage, ecology and the agricultural land classification if it sits on a former field.
- Permitted development (rooftop): no application, build once installer confirms PD compliance. Days, not months.
- Prior approval (some rooftop edge cases): a lightweight check with the council on siting/appearance — typically 56 days.
- Full planning (all factory-scale ground-mount): 8–13 weeks for a standard determination, longer if an Environmental Impact Assessment screening or ecology survey is triggered. Budget £3,000–£15,000 in consultant and application fees.
We handle the planning route end to end and time the G99 grid application to run in parallel. For the detailed PD limits, conservation-area rules and the prior-approval process, see our factory solar planning permission UK guide.
How much land for 250 kW, 500 kW and 1 MW?
A useful rule of thumb for UK fixed-tilt ground-mount is roughly 2.5–3 acres of usable land per megawatt. The range reflects inter-row spacing (set wide enough to avoid winter self-shading at UK latitudes), access tracks, fencing setbacks and DNO substation space. Tracker systems and tighter East–West layouts use less land per kWp but are rarely specified at factory scale. The figures below assume standard south-facing fixed-tilt rows.
| System size | Land needed (fixed tilt) | Approx. panel count | Est. annual generation |
|---|---|---|---|
| 250 kW | ~0.7–0.75 acres (~3,000 sqm) | ~450 panels | ~260,000 kWh/yr |
| 500 kW | ~1.3–1.5 acres (~6,000 sqm) | ~900 panels | ~525,000 kWh/yr |
| 1 MW | ~2.5–3 acres (~12,000 sqm) | ~1,800 panels | ~1,050,000 kWh/yr |
Generation figures assume ~1,050 kWh/kWp at optimal tilt in central England; expect 5–10% higher in the South West and lower in northern Scotland. A 1 MW array roughly matches the baseload of a mid-sized food-processing or plastics factory running extended shifts — but the value only lands if that generation is consumed on site rather than exported, so we size against your demand profile, not the available acreage.
Crucially, the land must be contiguous, broadly flat and clear of shading — 3 acres split across two shaded paddocks will not deliver the same output as 3 acres of open, south-facing ground. Slope, soil bearing for pile-driven frames, and the distance of the cable run back to your main intake all feed into the final layout and cost.
Ground-Mounted Solar Panels for UK Factories — FAQs
How much does this cost in the UK?
Mainstream Tier-1 commercial solar installs cost £700–£900 per kWp installed. See our cost guide for system-size breakdowns.
How long does the install take?
8–14 weeks from contract to commissioned system for systems up to 500 kW. The longest item is G99 grid connection (6–18 months DNO timeline) which we initiate before contract.
How is the system financed?
Four routes: capital purchase + AIA (best NPV), asset finance / lease-to-own (positive cash flow from month 1), PPA (zero capex), green business loan. See our financing guide.
How do I get a quote for my factory?
Submit a quote request with annual electricity spend and roof type. Free desk-based feasibility within 7 working days.
Get a free factory solar feasibility
Reply within one working day. Modelled against your real meter data, not industry averages.
More on factory roofs & solar mounting
Compare every option in our factory roof types for solar guide, check factory roof weight & load for solar, and review solar roof fire safety.
Continue Reading — Related Topics
Hand-picked guides covering the most relevant adjacent areas to this page.