A solar-only farm install typically captures 30–50% self-consumption. Add battery storage and that jumps to 70–90% — meaning you use your own clean electricity instead of buying it back at peak grid rates.
On a typical dairy or poultry farm where the heaviest loads run at dawn (milking) and dusk (ventilation, lighting), battery storage is the difference between exporting cheap solar at 4p/kWh during the day and importing at 32p/kWh at night, versus self-consuming at zero marginal cost around the clock.
Battery sizing for typical farm types
| Farm type | Solar kW | Battery kWh | Cost | Extra saving / yr |
|---|---|---|---|---|
| Dairy (200 head) | 50–80kW | 30–60kWh | £12k–£22k | £4,500 |
| Poultry (free-range) | 80–150kW | 50–100kWh | £18k–£35k | £7,200 |
| Arable (mixed) | 30–50kW | 15–30kWh | £8k–£15k | £2,400 |
| Pig (intensive) | 100–200kW | 60–120kWh | £22k–£40k | £8,800 |
| Glasshouse / horticulture | 200–500kW | 100–300kWh | £35k–£90k | £15,000+ |
Why LiFePO4 for farms
Lithium Iron Phosphate (LiFePO4) chemistry is the right pick for agricultural environments — it tolerates wider temperature ranges than NMC, doesn't catch fire under thermal runaway, and delivers 6,000+ cycles to 80% capacity (around 15 years on a one-cycle-per-day farm profile).
Critical-load backup for livestock farms
Configured with automatic transfer switching, the battery keeps milk cooling, ventilation fans, automated feeders and water pumps running through grid outages. For a 30,000-bird poultry shed, a 60kWh battery delivers ~6 hours of ventilation autonomy — enough to bridge the worst UK grid outage in modern records.
Stacking grants and finance
Battery storage qualifies for the same Annual Investment Allowance (AIA) as solar. FETF batches have, in recent years, expanded to include battery storage alongside solar. SEG-eligible export is unaffected — you continue to export when the battery is full.
Battery chemistries — what we install
The UK farm battery market in 2026 is dominated by lithium-iron-phosphate (LiFePO4) chemistry across three commercial-scale product families:
- Tesla Powerwall 3 — 13.5 kWh modular. Integrated inverter. Premium pricing but strongest install/commissioning experience. Best for <50 kWh applications.
- BYD Battery-Box Premium HVS / HVM — 5–22 kWh single, stackable to 84 kWh. Strong UK channel, 10-year warranty. Workhorse for 20–80 kWh systems.
- Pylontech US5000 / Force L2 — 4.8–7.1 kWh per module, rack-stackable to 100+ kWh. Best price-per-kWh in the volume tier. Common on poultry and dairy farms.
- SolaX Triple Power — 5.8–11.6 kWh modular. Decent UK warranty and channel.
- Sungrow SBR / SBH — utility-scale modular up to 384 kWh. The serious commercial choice for 150–500 kWh installations.
- BESS containers (>250 kWh) — purpose-built 20ft / 40ft shipping containers integrated with farm DC bus. For large multi-MW arrays or PPA-funded installations.
Use cases by farm type
| Farm type | Why battery matters | Typical battery |
|---|---|---|
| Dairy | Twice-daily milking (5am + 3pm) brackets the solar peak. Battery shifts midday surplus to dawn/dusk milking loads. | 30–60 kWh |
| Free-range poultry | 24/7 ventilation, overnight automated feed mill loads. High self-consumption baseline boosted by battery for 80–90%. | 50–100 kWh |
| Arable | Grain drying peaks Aug-Oct, otherwise low baseline. Battery less critical — system sized for export instead. | 15–30 kWh (or none) |
| Pig (intensive) | Continuous climate control + feed handling 24/7. Battery shifts huge midday surplus to night loads. | 60–120 kWh |
| Soft fruit / packhouse | Pre-cooling and pack-house refrigeration runs night-time in some operations. Battery enables Tesco scope-3 reporting. | 80–200 kWh |
Battery ROI economics — worked example
A 100kW solar array on a 200-cow dairy delivers 88,000 kWh/year. Without battery: ~55% self-consumed (48,400 kWh @ 30p saved = £14,520), 45% exported (39,600 kWh @ 8p SEG = £3,168). Total annual benefit: £17,688.
Add a 60 kWh LiFePO4 battery (£28,000 gross, £14,000 net after AIA + grant where eligible). Self-consumption rises to ~85% (74,800 kWh @ 30p = £22,440), 15% exported (13,200 kWh @ 8p = £1,056). New annual benefit: £23,496.
Marginal saving from adding battery: £5,808 per year. Marginal payback on the battery investment: 2.4 years. The battery essentially pays itself back at the same speed as the solar PV alone.
Grid services revenue (commercial-scale only)
For systems above 100 kWh battery capacity, there is an additional revenue stream from National Grid balancing services — Dynamic Frequency Response (DFR), Capacity Market, and Distribution-level flexibility programmes. Typical revenue: £40–£90 per kW per year. A 200 kWh battery participating in DFR can earn an additional £8,000–£18,000 annually on top of the energy arbitrage savings.