Solar PV for Cornwall polytunnel operations in 2026
Cornwall commercial farming is shaped by productive dairy in eastern valleys, mixed arable, the UK's largest early-season vegetable production concentration, Bodmin Moor upland livestock, Duchy of Cornwall tenanted holdings. Polytunnel operations across Cornwall represent one of the strongest solar PV deployments we deliver — Heated glasshouses and protected horticulture have massive supplementary lighting and heating loads. For a typical Cornwall polytunnel install in 2026, expect a system in the 100 kW–2 MW range, project value £90,000–£1.8m, simple payback 5.5 years before tax relief.
Cornwall-specific polytunnel considerations
The combination of Cornwall's agricultural intensity and the polytunnel sub-vertical's specific load profile creates strong economics for solar PV deployment. Most Cornwall polytunnel buildings have ample south- or east-west-facing roof area, structurally adequate cladding (or asbestos cement requiring combined re-roof + PV), and significant on-site electrical baseload that aligns with solar generation. Agrivoltaic translucent-panel installs need agronomic trial alongside structural assessment. Polytunnel structural reinforcement often required for rooftop PV — typically frame upgrade or perimeter ground-mount alternative. Defra and NFU horticulture engagement increasing.
Typical Cornwall polytunnel install
- System size
- 100 kW–2 MW
- Panel count
- 185–3,700
- Roof area
- 600–12,000 sqm
- Project value
- £90,000–£1.8m
- Simple payback
- 5.5 years
- Annual generation
- 92,000–1.85m kWh
- DNO
- National Grid Electricity Distribution
Why Cornwall polytunnel solar makes economic sense
The 2026 economics are dominated by three factors specific to Cornwall polytunnel operations: (1) on-site self-consumption ratio — Polytunnel buildings typically achieve high daytime PV self-consumption thanks to heated glasshouses and protected horticulture have massive supplementary lighting and heating loads; (2) Cornwall regional electricity tariffs sit in the 22–28p/kWh range for commercial supplies, meaning each self-consumed kWh saves 1.5–3× what an exported kWh under SEG returns; (3) 100% Annual Investment Allowance applies to the full capex in year one, delivering effective 25% tax relief for incorporated farms. Combined, these drive payback periods of 5.5-yr nominal and roughly 3.7-yr after-tax.
Combined re-roof + PV on older Cornwall polytunnel buildings
Many Cornwall polytunnel buildings pre-date 2000 and carry asbestos cement cladding. Under Control of Asbestos Regulations 2012, asbestos cement cannot be retrofitted with PV. The standard solution is a combined re-roof + PV project: HSE-licensed asbestos removal (£30–£50/sqm), profiled steel re-cladding (£45–£80/sqm), then PV install on the new roof. The PV business case routinely pays for 60–100% of the re-roof over the 25-year system life. We've delivered combined re-roof + PV across Cornwall regularly since 2019.
Cornwall polytunnel solar — key features
- Heated glasshouses and protected horticulture have massive supplementary lighting and heating loads
- Vertical farming and CEA sites exceptionally good PV fit
- Agrivoltaics over polytunnels emerging quickly (translucent panels, semi-shade-tolerant crops)
- Soft fruit, salads, ornamentals — supermarket-facing producers under Scope 3 pressure
How we deliver Cornwall polytunnel solar
Every project starts with a free desk-based feasibility study. Send us your half-hourly meter data and building dimensions; we share an indicative system size, generation forecast, self-consumption ratio, and 25-year financial model within 7 working days. If the numbers work, our engineers visit for a one-day structural and electrical survey. We deliver a fixed-price proposal with full PVSyst yield modelling and DCF financial model. From contract: typical 4–7 months to commissioning for rooftop installs; 6–9 months for combined re-roof + PV. We schedule physical works around the polytunnel operation's busy seasons.
For more on polytunnel solar generally see our Polytunnel specialist page; for wider Cornwall farm solar coverage see Cornwall Farm Solar.
Common questions
How much does a Cornwall polytunnel solar install cost?
Typical Cornwall polytunnel installs in 2026 range from £90,000–£1.8m, depending on roof area, electrical capacity and whether re-roofing is required. Cost per kW: £800–£1,000 for sub-100 kW, £750–£900 for 100–250 kW, £700–£850 for above 250 kW. We provide fixed-price proposals within 7 working days of receiving meter data.
Do you cover all Cornwall farm locations?
Yes — we deliver across the entire Cornwall agricultural region. Whether your polytunnel is in a major town or a remote rural location, we provide the same fixed-price desk feasibility and on-site survey. Most Cornwall locations are accessible within 60–90 minutes of our base.
What is the Cornwall grid connection process for polytunnel solar?
National Grid Electricity Distribution is the regional DNO covering most of Cornwall. G99 connection timelines run 65–90 working days for technical study, 6–14 months for full connection on most rural feeders. We submit G99 immediately after structural survey to compress timeline. For export-constrained sites we design "no-export" systems sized for self-consumption that connect in 6–8 weeks.
What is the typical payback for Cornwall polytunnel solar?
Simple payback 5.5 years before tax relief, pulled to approximately 3.7 years after 100% Annual Investment Allowance for incorporated farms at 25% corporation tax. 25-year IRR typically 13–17%.
What grants are available for Cornwall polytunnel solar?
Headline schemes: 100% Annual Investment Allowance (universal); Smart Export Guarantee 8–15p/kWh on surplus; Sustainable Farming Incentive 2025 biodiversity actions; Farming Investment Fund where solar pairs with eligible items (robotic milking, grain dryers). Welsh and Scottish farms have additional devolved schemes.