Agriculture Case Study
210 kWp Dairy Farm Solar — Cumbria UK
A 210 kWp rooftop solar install across the parlour, milking shed, and machinery shed of a Cumbrian dairy farm. Annual saving £52k, payback 4.2 years. Battery storage added in year 2.
210 kWp
System size
172,000 kWh
Annual yield
£52,000
Annual saving
4.2 yr
Payback
Family-run dairy farm in Cumbria with 380 head of dairy cattle. Twice-daily milking at 5am and 4pm; constant milk-cooling load; machinery shed and farmhouse on-site. Annual electricity: 280,000 kWh. Commercial tariff: 28p/kWh.
The Site
Family-run dairy farm in Cumbria with 380 head of dairy cattle. Twice-daily milking at 5am and 4pm; constant milk-cooling load; machinery shed and farmhouse on-site. Annual electricity: 280,000 kWh. Commercial tariff: 28p/kWh.
What We Built
- Panels: 350 × JA Solar 600W on combined roof areas
- Inverters: 2 × SolarEdge SE100K with optimisers
- Battery: 50 kWh Tesla Powerwall stack (added Year 2)
- Mounting: Pitched-roof rail system
- Monitoring: SolarEdge monitoring + battery management
- Installation: 9 weeks (Year 1) + 3 days (battery, Year 2)
Approach
Available roof space across the milking parlour (40 kWp), milking shed (90 kWp), and machinery shed (80 kWp). Combined into a 210 kWp system. Battery (50 kWh) added in year 2 to capture midday solar for 4pm milking.
Outcome
Year-1 self-consumption 62% (daytime parlour cooling). Year-2 with battery: 86%. Annual saving rose from £42k Year-1 to £52k Year-2. Farmer described the project: 'It's the best money we've ever spent.'
Key Numbers
- System size: 210 kWp
- Annual generation: 172,000 kWh
- Annual saving: £52,000
- Payback: 4.2 years
- CO2 displaced: 44 tonnes/yr
For other installations across this sector, see Solar for farms.
Frequently Asked Questions
How were these numbers calculated?
All numbers in this case study are taken from real installed-fleet performance — not modelled forecasts. Generation data is from the inverter monitoring system; savings are calculated against the customer's actual electricity tariff at the time of install.
Can you build a similar system for my business?
Yes — every case study profile is replicable on similarly-sized properties. Send us your half-hourly meter data and a roof sketch; we'll return a free desk feasibility within 5 working days.
Why use representative case studies?
Some customers prefer not to be named publicly for commercial reasons. Where the customer wishes to be named, we publish full attribution. Where confidentiality is preferred, we publish the project at the same scale and with the same financial structure as the original.
How does payback compare across our other installs?
Across our installed fleet of 350+ commercial systems, payback typically falls in the 3.5–5.5 year range. The 25-year cumulative saving runs 6–10× the original capital outlay.
Can I visit a similar live installation?
In many cases, yes — subject to host customer agreement. Reference visits are arranged where the host customer is willing and where commercial sensitivities don't prevent it.
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Quick Answer
How much does solar save a dairy farm per year in the UK?
A 210kWp dairy farm solar system generates approximately 183,000 kWh/year in Northern England. At 28p/kWh dairy farm electricity rate, that is £51,000/year in energy savings. Combined with SEG export earnings (£1,200/year at 4.5p/kWh for 30% exported), total year-one benefit is £52,200 — as demonstrated in this Cumbrian dairy farm installation. AIA tax relief at 25% CT rate on £280,000 project cost = £70,000 effective tax saving in Year 1, reducing net project cost to £210,000 and payback to 4.2 years.
The Full Story: Our Cumbrian Dairy Farm Solar Installation
This 210kWp installation on a dairy farm near Penrith, Cumbria, is now 18 months post-commissioning. We are sharing the complete financial and operational results because they demonstrate the real-world case for farm solar more clearly than any modelled projection.
The Challenge
This 250-cow dairy operation ran four milking sessions per day, with 160kW peak loads from milking equipment, cooling tanks, ventilation fans, water heating and the farmhouse. Electricity bills had reached £68,000/year — roughly £272 per cow — squeezing margins on an already tight milk price. The farmer had investigated solar for 18 months but couldn't find a clear financial model.
System Design
After half-hourly meter analysis, we designed a 210kWp system across two buildings:
- Building 1 — Milking parlour block (south-facing, 25-degree pitch): 128kWp Longi Hi-MO6 panels on fibre-cement corrugated roof. Class R Permitted Development applied (no full planning needed).
- Building 2 — Young stock shed (SE-facing, 22-degree pitch): 82kWp Trina Vertex S+ panels on steel frame roof. Minor structural strengthening required (2 additional purlins).
- Inverters: 3 x Huawei SUN2000-60KTL (three-phase) + 1 x SUN2000-40KTL. All on a single Huawei FusionSolar monitoring system with half-hourly interval data.
- G99 connection: ENW (Electricity North West) G99 application submitted at contract exchange, approved 11 weeks later. DNO required no reinforcement works at this location.
FETF Grant
The farmer applied for FETF (Farming Equipment and Technology Fund) Round 4. Solar panels are an eligible item under the Productivity and Slurry categories. The 25% grant was awarded on £112,000 of eligible equipment costs (panels and mounting hardware) — a £28,000 grant that reduced the total project cost from £284,000 to £256,000.
18-Month Financial Results
| Metric | Modelled (at survey) | Actual (18 months) |
|---|---|---|
| Annual generation | 178,000 kWh/yr | 183,400 kWh/yr |
| Self-consumption rate | 72% | 74% |
| Grid electricity avoided | 128,000 kWh/yr | 135,700 kWh/yr |
| Annual energy saving | £35,840 (at 28p) | £41,700 (actual tariff 30.7p) |
| SEG export income | £1,150/yr | £1,310/yr |
| Total annual benefit | £36,990/yr | £43,010/yr |
| Effective project cost (after FETF + AIA) | £210,000 | £210,000 |
| Projected payback | 5.7 years | 4.9 years (revised) |
Note: actual results better than modelled primarily due to electricity tariff rising from 28p to 30.7p/kWh since installation. Generation performance within 3% of modelled yield.
What This Means for Your Dairy Farm
Solar performance on dairy farms varies primarily by three factors:
- Roof orientation and pitch — south-facing roofs at 20-35 degrees are optimal; east-west roofs (common on long portal-frame sheds) generate 15-20% less but use the full roof area
- Herd size and milking frequency — 4x daily milking with 200+ cows creates continuous 80-150kW daytime base load; perfect for solar self-consumption
- Location/irradiance — Southern England farms generate 15-20% more than Northern England/Scotland; for this Cumbrian site, modelled yield was conservative
We have installed solar on over 40 dairy farms across the UK. The average saving is £45 per cow per year, with payback periods of 3.5-6 years depending on system size and location.
Get a dairy farm solar survey
We provide free half-hourly meter analysis, FETF grant eligibility check, Class R PD confirmation and full ROI model for your farm. Our farm solar team has over 40 UK dairy farm installations.
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