Commercial Solar Battery Storage in the UK
Commercial solar battery storage lets businesses store surplus daytime generation and use it during evenings, overnight shifts or expensive peak-rate periods. Installed costs run £400-£700 per kWh of capacity, and batteries qualify for the same 100% first-year tax relief as the solar system itself. This guide covers commercial battery costs, sizing, payback and the systems that dominate the UK market.
Quick Answer
Commercial solar battery storage costs £400-£700 per kWh installed in the UK. A 100 kWh commercial battery costs £40,000-£70,000, qualifies for 100% Annual Investment Allowance tax relief, and pays back fastest for businesses with evening electricity use or time-of-use tariffs with expensive peak periods.
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What commercial battery storage does for a business
Higher self-consumption
Without a battery, a business closed at weekends may export 30-50% of its solar generation for a few pence per kWh. A battery shifts that energy to Monday morning, where it offsets electricity costing 25-30p/kWh.
Peak shaving
Businesses on half-hourly or time-of-use tariffs pay steep prices at peak times (typically 4-7pm). Discharging the battery through the peak window cuts both unit charges and, for larger sites, capacity-related charges.
Export limit workaround
Where the DNO caps your export under G99, a battery absorbs generation that would otherwise be curtailed, protecting the business case for a bigger solar array.
Backup power
Some commercial battery systems provide backup for critical circuits (refrigeration, IT, tills) during power cuts. Backup capability adds cost, so specify it only if downtime is genuinely expensive for your business.
Commercial solar battery storage costs
Commercial battery costs scale with usable capacity and power rating. As with solar, cost per kWh falls as systems grow.
| Battery Size | Typical Use Case | Installed Cost (est.) | Cost per kWh |
|---|---|---|---|
| 13.5 kWh | Small shop or office (single Powerwall 3) | £8,000-£11,000 | £590-£815 |
| 30 kWh | Restaurant, surgery, small workshop | £12,000-£21,000 | £400-£700 |
| 100 kWh | Warehouse or factory with 100 kWp solar | £40,000-£70,000 | £400-£700 |
| 250 kWh | Industrial site, cold storage, agriculture | £90,000-£150,000 | £360-£600 |
Estimates exclude VAT (20%, reclaimable for VAT-registered businesses). Batteries installed with commercial solar qualify for the Annual Investment Allowance. For domestic battery prices, see our home solar battery storage guide.
Commercial solar battery systems to consider
Tesla Powerwall 3
Stackable to 4 units (54 kWh), with an integrated solar inverter. A strong fit for small commercial sites on single-phase or small three-phase supplies. See our Tesla Powerwall guide.
Sigenergy SigenStor
Modular stacks scaling from 8 kWh to large three-phase commercial systems, with high charge and discharge rates that suit peak shaving.
FoxESS and BYD
Rack-mounted commercial batteries that scale to hundreds of kWh. Common choices for warehouse and industrial projects where capacity per pound matters most. See our FoxESS review.
Commercial battery storage FAQ
How much does commercial solar battery storage cost in the UK?
Commercial battery storage costs £400-£700 per kWh of usable capacity installed. A 30 kWh system for a small business costs £12,000-£21,000, while a 100 kWh system for a warehouse or factory costs £40,000-£70,000. Costs per kWh fall as systems get larger, and batteries qualify for capital allowances.
Are commercial solar batteries worth it?
Commercial batteries pay off fastest for businesses with evening or overnight electricity use, sites on time-of-use tariffs with expensive peak periods, or sites with export limits on their solar system. Where most solar generation is already used on site during the day, a battery adds resilience but extends the overall payback.
What size commercial battery does my business need?
A rough starting point is 1-1.5 kWh of battery capacity per kWp of solar for businesses wanting to shift surplus generation into the evening. The right answer comes from half-hourly consumption data: an installer should model your import profile against solar generation to size the battery, not guess from your annual bill.
Which are the best commercial solar batteries?
For small commercial sites, Tesla Powerwall 3 units can be stacked up to 4 units (54 kWh). Above that, three-phase commercial systems from Sigenergy (SigenStor), FoxESS and BYD scale to hundreds of kWh. The right choice depends on your inverter setup, phase supply and whether you need backup power.
Do commercial batteries qualify for tax relief?
Yes. Battery storage installed as part of a commercial solar project qualifies for capital allowances, including the Annual Investment Allowance, letting businesses deduct 100% of the cost from taxable profits in the first year. VAT at 20% applies but is reclaimable for VAT-registered businesses.
Related guides
- Commercial solar panels UK: the complete guide
- Commercial solar panel costs
- How to find a commercial solar installer
- Home solar battery storage
- Solar battery brands compared
John Rooney is the founder of Solar Info and has been covering the UK solar energy market since 2023. He researches every battery and inverter brand against manufacturer datasheets, MCS and Ofgem data, and feedback from the MCS-certified installers in our directory before publishing.
Sources
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