Commercial battery storage: store your solar, cut peak costs

Commercial battery storage: the key facts

What is commercial battery storage, and who is it for?

Commercial battery storage is a battery system (cells, a battery management system, an inverter and controls) installed at a business site and connected to your electrical supply. It charges from your solar panels or from the grid, and discharges into your own building when power is worth more.

Battery storage for business makes most sense where at least one of these is true:

• You have, or are adding, solar that produces more than you use at midday or at weekends.
• Your DNO has limited your export, so surplus solar would otherwise be thrown away.
• You pay time-of-use rates, or network charges that peak in the late afternoon and early evening.
• You pay capacity or maximum demand charges and have short, sharp peaks: compressors starting, ovens, kilns or EV chargers.
• Your supply is constrained and you want to add load, such as EV chargers, without an expensive upgrade.

If your use is flat, you have no solar and you pay a single flat unit rate, a battery has little to work with. An honest installer will tell you that.

Four ways a business battery saves money

Most projects stack two or more of these. The controls decide, half-hour by half-hour, which job the battery does, so the strategy matters as much as the hardware.

Commercial solar and battery storage together

Solar and storage are usually designed as one system. The roof sets how much energy is available; the battery decides how much of it you get to use.

• Self-consumption: every kWh used on site saves your full delivered unit rate, including the non-commodity charges and the Climate Change Levy on grid power (0.801p per kWh from 1 April 2026). Every kWh exported earns your SEG rate, which is usually much lower. A battery moves kWh from the second group to the first.
• Bigger arrays on limited grids: with a battery, a site under an export cap can justify more panels than it could otherwise.
• Weekends and holidays: offices, schools and single-shift factories can store weekend output for Monday morning.
• Retrofit or new build: a battery can be added to existing solar, but check the inverter. AC-coupled batteries are the usual retrofit route; DC-coupled hybrid systems suit new installs.

The Smart Export Guarantee pays for solar you export, on systems up to 5MW in Great Britain. Suppliers set their own rates; the law only says the rate must be above zero, so shop around. If you export from a battery, ask your SEG supplier how it treats stored electricity, as terms vary.

See the sector guides: warehouse solar (big roofs, export limits), factory solar (peak shaving) and farm solar (rural grid limits, evening milking).

Sizing a commercial battery: kWh vs kW

Every battery has two headline numbers, and you need both:

A battery for peak shaving needs high kW for a short time. A battery for storing a whole afternoon of solar needs plenty of kWh. Sizing comes from your half-hourly data and your solar generation profile, modelled together. Bigger is not always better: the last few kWh of a large battery may rarely fill.

Safety and siting: where a business battery should go

Commercial lithium-ion batteries store a lot of energy in a small space, so siting and fire safety need proper design. Follow the installer's design and the manufacturer's installation instructions, and bring in your insurer early.

• Location: outdoor enclosures or dedicated plant rooms are common for larger systems. Keep batteries away from escape routes, and from storage of flammable goods.
• Ventilation and temperature: batteries have an operating temperature range. Too hot or too cold shortens life and can stop the system.
• Access: clear access for maintenance and for the fire service, with isolation points and signage.
• Fire risk assessment: under the Regulatory Reform (Fire Safety) Order 2005, the responsible person for business premises in England and Wales must keep a fire risk assessment. Update it when a battery is installed.
• Insurance: tell your insurer before you install. Some set their own conditions on location, separation and monitoring.
• Planning: check with your local planning authority if the battery goes in an outdoor enclosure or a new building, especially near homes or on a listed site.

Commercial battery storage costs: how they're priced

There's no official national price series for commercial batteries. The DESNZ solar cost data that we use for solar prices specifically excludes battery storage, so we don't publish a cost per kWh for business batteries. Be wary of anyone quoting a single headline figure without seeing your site.

What a commercial battery quote should break down:

• Battery modules and the rated and usable kWh
• Inverter or power conversion system and its kW rating
• Enclosure, foundations or plant-room works, and fire protection
• Electrical works: switchgear, cabling, metering and any backup changeover
• DNO application, if the battery can export or changes your connection
• Controls and software, including any subscription for tariff optimisation
• Commissioning, monitoring, maintenance and warranty terms

Ask for the battery priced separately from any solar, with its own savings model, so you can see what each part earns. For solar prices, see commercial solar panel costs.

Business rates, VAT and tax on commercial batteries

Business rates: in England, plant and machinery used for the generation or storage of power is excluded from rateable value until 1 April 2035, where the energy source relied on is mainly or exclusively renewable, such as solar. So a battery that stores your rooftop solar should be covered. A battery that charges mainly from the grid may not be, so check with your rating adviser. Storage used mainly for an EV chargepoint has its own exclusion. Wales and Scotland have similar exemptions running to 2035.

VAT: Ordinary business premises pay 20% VAT on solar, batteries and heat pumps, which VAT-registered businesses can normally reclaim. The 0% rate is only for homes and buildings used solely for a relevant charitable purpose, and it runs to 31 March 2027.

Capital allowances: HMRC's guidance is explicit that solar panels are special-rate plant, but it doesn't set out the treatment of battery storage in the same way. Don't assume a battery qualifies for a particular allowance or rate. Ask your accountant before you commit, especially if the battery is bought together with solar.

Grants: There is no single national grant that pays for business solar, batteries or efficiency upgrades in England. The money comes from tax allowances, the business rates exemption, export payments, the Boiler Upgrade Scheme, the Workplace Charging Scheme and local or sector funds. The farm grant round that covered solar PV systems, including solar batteries, has closed. In Wales, the Development Bank of Wales Green Business Loan Scheme lends £1,000 to £1.5 million over up to 15 years, at a discounted rate and with no arrangement fee, for projects including solar PV and heat pumps. It also offers an energy audit grant of up to £10,000. In Scotland, Business Energy Scotland's SME Loan offers no cashback on batteries. See the business energy grants hub and commercial solar grants.

Batteries and EV charging on a limited supply

Adding EV chargers for staff or a fleet can push a site past its supply capacity. A battery can top up the chargers during busy periods, and store solar for daytime charging, which can delay or avoid a costly supply upgrade.

The Workplace Charging Scheme still helps with the chargepoints themselves: The Workplace Charging Scheme pays up to £500 per socket (it went up from £350 on 1 April 2026), capped at 75% of costs, for up to 40 sockets across all your sites. That's up to £20,000. Funding runs until 31 March 2027, its final year. The EV infrastructure grant for staff and fleets and the commercial landlord chargepoint grant both closed to applications on 31 March 2026. Read business EV charging and the Workplace Charging Scheme.

What to prepare, and what to ask battery installers

Prepare

• 12 months of half-hourly data, and bills showing your tariff, time bands and any capacity charges
• Your solar details if you have it: size, inverter make, SEG tariff and any export limit
• Your MPAN, supply capacity and any DNO correspondence
• Where a battery could go: outdoor space, plant room, distance to the main switchboard
• Plans for EV chargers, new equipment or electrified heating

Ask every installer

• Which use cases is the battery sized for, and what is the saving from each?
• What are the rated and usable kWh, the kW rating and the round-trip efficiency?
• What do the warranty terms cover in years, cycles or throughput, and what capacity is guaranteed at the end?
• How will it be sited for fire safety, ventilation and access, and has my insurer been consulted?
• Does it provide backup in a power cut, and for which circuits?
• Does it need a DNO application, and who handles it?

Next steps: from enquiry to a working battery

1. Send the basics through the form on this page. We pass your enquiry to one commercial installer.
2. Data analysis: the installer models your half-hourly data, tariff and any solar to find the right kWh and kW.
3. Site survey: location, electrical connection, access and fire safety.
4. DNO application where needed, and design sign-off with your insurer.
5. Install and commissioning, usually with a short planned shutdown for the electrical tie-in.
6. Controls and monitoring: set the strategy, then check the savings against the model and adjust.

Thinking about solar first? Start with commercial solar panels.