Battery storage for business that cuts peak charges, stores your solar and unlocks constrained connections
Battery storage for business has moved from a niche bolt-on to a core energy-cost and resilience strategy for UK companies. The value now sits in avoiding red-band charges, shifting load out of expensive half-hours by charging off-peak and discharging at peak, and lifting self-consumption from on-site solar rather than spilling it to the grid at a low export rate. A correctly sized commercial battery does several jobs at once: it shaves your demand peaks, it stores cheap or self-generated power for use when electricity is most expensive, it backs up critical loads against outages, and on larger assets it can earn stacked revenue from grid services. The discipline is simple to state and harder to do well: size from real half-hourly meter data, model every saving honestly, and design to current grid and fire-safety standards. That is what we do, and it is all this page is about.
Why businesses install battery storage: the value stack
The case for a commercial battery is not one big saving but several smaller ones stacked together. Peak shaving is usually the foundation: Distribution Use of System (DUoS) charges vary by time-of-day band, and the red band, typically weekday late afternoon into early evening, costs far more per kWh than the green or amber bands. A battery that discharges across those red half-hours cuts both the unit charges and the capacity-based standing charges, while charging back up overnight on a cheap tariff. Load shifting is the same mechanism applied to wholesale prices, storing cheap power and using it when it is expensive. Solar self-consumption closes the gap that most solar sites leave open: a solar-only commercial site typically self-consumes only 40 to 60 percent of what it generates, exports the rest at a low Smart Export Guarantee rate, then re-imports in the evening at full retail. A battery sized to your daytime surplus lifts that self-consumption toward 80 percent and above. Backup and resilience protects critical loads from grid outages, cleaner and quieter than diesel standby. And for larger assets, grid services and revenue stacking add upside, though we treat that as a bonus, never the core case, because frequency-response prices have become volatile and saturated.
How we size systems: kWh capacity versus kW power
A commercial battery is sized by two separate numbers that are easy to confuse. Power, measured in kW, is set by the size of the peak you need to shave or the load you need to support. Energy, measured in kWh, is set by how long that peak lasts. Most behind-the-meter commercial systems land at 1.5 to 2.5 hours of duration, for example a 250 kW unit backed by 500 kWh of usable capacity. The other levers are depth of discharge (how much of the rated capacity you can use without shortening cell life) and round-trip efficiency (the energy lost charging and discharging), both of which we account for so the usable figure is honest rather than the nameplate. For solar-plus-storage we size the battery to your daytime export surplus, not your headline solar kW. For peak shaving we model the red-band DUoS half-hours and the capacity-chargeable window. We always pull at least 12 months of half-hourly meter data and confirm your import and export capacity with the network early, because the grid connection is usually the long pole. Sizing ranges run from a 50 kW / 100 kWh solar-plus-storage system up to 2 MW / 4 MWh where the job is to unlock a constrained connection.
Costs, payback and tax relief
As a 2026 rule of thumb, fully installed commercial battery storage lands at roughly £400 to £700 per kWh of usable capacity for behind-the-meter systems, falling toward £250 to £400 per kWh at multi-MWh scale. A typical 250 kW / 500 kWh peak-shaving system is around £150,000 to £300,000; a 1 MW / 2 MWh system around £600,000 to £1.2m. Simple payback for behind-the-meter systems doing peak shaving and solar self-consumption typically falls between 6 and 8 years in 2026, faster where red-band DUoS exposure or solar surplus is high. Tax relief is where the largest single saving lives. A qualifying battery is plant and machinery, so the first one million pounds of qualifying spend is relieved at 100 percent through the Annual Investment Allowance, and as storage is a special-rate asset any qualifying expenditure beyond that cap attracts the 50 percent First-Year Allowance, together worth an effective year-one saving of up to roughly a quarter of the project value for a limited company. These figures are illustrative and depend on your accounting period, so confirm the position with your accountant. Our cost guide works the numbers through from your own bill.
Funding routes
Most of the storage we deliver does not have to be paid for from capital. The plant and machinery capital allowances are the headline route, with 100 percent Annual Investment Allowance on the first one million pounds and a 50 percent First-Year Allowance on the balance. The Smart Export Guarantee turns surplus into income, and a battery adds most of its value here by timing export into higher-priced windows rather than spilling at midday. Where a building is residential accommodation or used solely for a relevant charitable purpose, the 0 percent VAT relief on energy-saving materials can apply to standalone retrofit battery storage, a relief that runs to 31 March 2027 before reverting to 5 percent, though it does not apply to general commercial premises such as a standard factory or warehouse. For industrial sites, the Industrial Energy Transformation Fund can support storage where it forms part of a wider qualifying decarbonisation project, not as a standalone battery. And NESO grid services can add upside on larger assets, treated as a bonus only. Our funding routes page sets out each scheme, its eligibility and its caveats in full.
Compliance and safety considerations
Modern commercial battery storage is governed by real standards, which is exactly what makes it insurable. A G99 connection agreement is required for storage above 16 A per phase (about 3.68 kW single-phase), which covers most commercial systems, while G100 is an export and import limitation scheme that holds a site within its agreed capacity, typically reacting within 15 seconds (and no more than 60 seconds). On the safety side we design to BS EN 62619 for cell safety, BS EN/IEC 62933 for system safety, and PAS 63100:2024 principles for installation and fire protection, with NFCC guidance for larger sites. We specify lithium-iron-phosphate (LFP) chemistry, which is far more thermally stable than older nickel-manganese-cobalt cells, plus battery management, thermal monitoring, fire detection and appropriate separation, and we engage your insurer up front. Siting matters too: separation distances, access for firefighting and noise all feed the design, and where a battery sits near a hazardous zone, DSEAR and ATEX considerations apply. Behind-the-meter enclosures on an existing site are often permitted development or a minor application; larger standalone systems need full planning permission and fire-and-rescue consultation. The risk lies in cheap, non-compliant kit, which we do not install.
How we approach the project
We start with at least 12 months of your half-hourly meter data and your current DUoS band schedule, because storage is a data exercise before it is an engineering one. We model power and duration against your peaks, your solar surplus and the charges that actually cost you money, and we build the case on demand-charge avoidance and self-consumption you control, treating any grid-services or export income as upside. We submit the G99 application alongside the survey so the network clock starts on day one, and use a G100 limitation scheme where it lets a project proceed on a constrained connection. You receive a fixed-price proposal stating the warranted cycle count and degradation curve, an insurance-backed warranty, and the full model so your finance team can stress-test every assumption. We will tell you plainly if your demand profile does not justify a battery, flat, low-peak loads often do not. From contract to commissioning typically takes four to nine months, the network connection being the longest item.
An illustrative example
As an illustrative composite based on typical UK projects, and not a real named client: a precision-engineering plant on a single-shift-plus profile ran a sharp weekday late-afternoon demand peak that overlapped the red DUoS band, alongside an existing 300 kW rooftop solar array spilling midday surplus. We modelled a 250 kW / 500 kWh lithium-iron-phosphate battery integrated with the existing solar. In the model, solar self-consumption lifted from around 52 percent toward 84 percent, the late-afternoon red-band import fell sharply, and the combined saving reflected both recovered solar and reduced capacity and demand charges, with the full case built from twelve months of half-hourly data and handed to the finance director to stress-test. Any frequency-response income was treated as unmodelled upside. The figures are illustrative and depend on your site, load profile, tariff and use case.
Whatever your starting point, the right design begins with your data. If your priority is flattening demand peaks, see our page on peak shaving and load shifting; if you already run solar, solar-plus-storage is usually the highest-return route. When you are ready, read the cost guide and funding routes, browse the battery storage FAQs, or request a free feasibility built from your half-hourly meter data.
