Commercial solar panels for Cornwall businesses

Why Cornwall businesses are moving on commercial solar in 2026

Three things have changed in the last 24 months. First, panel prices have dropped around 22% from 2023 highs, so system costs per kWp are the lowest they have ever been in the UK. Second, business electricity rates stabilised above 25p/kWh commercial average, roughly double pre-2022 levels — meaning self-generated electricity is worth far more than it was. Third, Annual Investment Allowance (AIA) at £1m per year lets most SMEs deduct 100% of the install cost against taxable profits in year one.

The combined effect is that a well-sized commercial PV system on a Cornish farm, packhouse, dairy, workshop or office building now pays back in roughly 5 to 7 years, with another 18 to 20 years of near-free electricity afterwards. In a lot of cases the system is cheaper than doing nothing once you account for tax relief.

Where commercial solar works best in Cornwall

Cornwall's commercial solar sweet spot is any business with significant daytime electricity use and a south, east or west-facing roof that is structurally sound. The list we install for most often:

• Farms and agricultural buildings — barns, grain stores, dairies. Huge roof areas, high daytime load from pumps, fans, refrigeration.
• Cold storage and packhouses — almost perfect match: constant compressor load through daylight hours.
• Workshops, garages and MOT stations — compressor, lighting and lift loads all sit in the solar generation window.
• Offices and professional services — tend to benefit more with battery storage paired.
• Retail and hospitality — refrigeration, lighting and HVAC are all daytime loads; SEG income tops up from weekends.
• Industrial units and light manufacturing — often ideal when production runs 8am–5pm on weekdays.

System sizes and indicative costs

Every quote is bespoke. As a rough guide:

• 20 kWp — around 50 panels, £16,000 to £22,000 installed, typical for small workshops and retail units.
• 50 kWp — around 120 panels, £38,000 to £48,000 installed, suits packhouses, small dairies, medium offices.
• 100 kWp — around 235 panels, £70,000 to £85,000 installed, larger farms, industrial units.
• 250 kWp — roof-scale, £165,000 to £200,000 installed, significant industrial or agricultural sites.

All prices exclude VAT (commercial solar is standard-rated at 20% VAT but reclaimable by VAT-registered businesses). Price ranges depend on mounting system, whether ground-mount or roof, single or three-phase inverter, and distance from consumer unit to array.

The G99 process we handle for you

Anything above 3.68kW single-phase or 11.04kW three-phase needs a G99 connection agreement from the DNO (National Grid Electricity Distribution, covering Cornwall). We handle G99 submissions on every commercial project. Realistic timelines:

• Up to 50kW — usually 6 to 10 weeks for DNO approval.
• 50kW to 250kW — 12 to 20 weeks typical; may require a network study.
• Above 250kW — 20+ weeks; often needs substation reinforcement.

We recommend starting the G99 process before ordering equipment, because DNO acceptance often drives the earliest possible install date.

Capital allowances and tax relief

Commercial solar PV is plant and machinery for tax purposes and qualifies for the Annual Investment Allowance. For most SMEs that means 100% deduction against taxable profits in year one. Larger businesses with capex above £1m should discuss Full Expensing with their accountant. The documentation we provide includes the full equipment schedule, supply/install split, MCS certificate, and G99 evidence — everything your accountant needs to file the allowance.

Commercial battery storage

For offices, retail, and hospitality sites with lower daytime baseload, we frequently pair solar with commercial battery storage. Batteries let you self-consume more solar, peak-shave against half-hourly maximum demand charges, and in some cases participate in dynamic tariffs or frequency response. Typical commercial battery sizes we install range 20kWh to 150kWh. We work with Fox, Sigenergy and Tesla commercial products.

What happens next

Our commercial process starts with a feasibility study — free for any Cornwall business. We ask for 12 months of half-hourly meter data (your supplier can provide this), do a roof survey, and produce a modelled return-on-investment report. If the numbers work, we proceed to G99 submission, detailed design and installation. Contact us to start a feasibility study or call 01209 596 002.