Battery storage for business, FAQs

As a 2026 rule of thumb, fully installed commercial BESS lands at roughly £400-£700 per kWh of usable capacity for behind-the-meter systems, falling toward £250-£400/kWh at multi-MWh scale. A typical 250 kW / 500 kWh peak-shaving system is around £150,000-£300,000; a 1 MW / 2 MWh system £600,000-£1.2m; grid-scale assets run into the millions to tens of millions. Cost depends on power-to-energy ratio, chemistry, switchgear, and any grid-connection works. Qualifying plant attracts 100% AIA on the first £1m and a 50% first-year allowance on the balance.

Both, and they are different. Power (kW) is sized to the peak you need to shave or the charger/load you need to support; energy (kWh) is sized to how long that peak lasts. Most behind-the-meter commercial systems land at 1.5-2.5 hours of duration, for example 250 kW / 500 kWh. We pull at least 12 months of half-hourly meter data and model power and duration against your DUoS bands and solar surplus before recommending a size.

DUoS (Distribution Use of System) charges vary by time-of-day band, the red band (typically weekday late-afternoon/early-evening) is far more expensive per kWh than green or amber. A battery charges in cheap periods and discharges across the red band and your demand peaks, cutting both the unit charges and the capacity-based standing charges. It also reduces exposure to the Capacity Market and residual charges. The saving is largest for sites with spiky, predictable demand.

The old Triad regime (three winter-peak half-hours that set transmission charges) has been replaced by fixed, banded residual charges, so the classic 'Triad avoidance' play no longer exists in its old form. Value has shifted to DUoS red-band avoidance, demand-charge reduction, capacity-market exposure, and solar self-consumption, all of which a battery captures. We model the current charging structure, not the old Triad approach.

Often yes. Solar-only commercial sites typically self-consume only 40-60% of what they generate and export the rest at a low SEG rate, then re-import in the evening at full retail. A battery sized to your daytime surplus stores that energy for evening and early-morning use, lifting self-consumption toward 80%+ and capturing the spread between import and export prices. The right battery size is set by your surplus profile, not your headline PV kW.

Frequently. A behind-the-meter battery with a G100 export/import limitation scheme can let you add EV charging, heat pumps, or production capacity while staying within your existing agreed import/export capacity, avoiding or deferring a costly DNO reinforcement and a long connection queue. The G100 scheme reduces import or export to stay within the agreed limit, typically reacting within 15 seconds. We confirm the approach with your DNO before final design.

Correctly specified modern systems are governed by real safety standards: 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 grid-scale sites. We use lithium-iron-phosphate (LFP) chemistry, which is far more thermally stable than older NMC cells, plus battery management, thermal monitoring, fire detection, and appropriate separation. The risk lies in cheap, non-compliant kit, not in standards-compliant commercial BESS.

G98 covers small-scale connections; G99 is the connection agreement for storage above 16 A per phase (about 3.68 kW single-phase), which is most commercial systems; G100 is an export (and import) limitation scheme that keeps a site within its agreed capacity. Many projects use G99 plus G100 together so they can proceed on a network where full export capacity is not available. We handle all three and submit early because the DNO timeline is usually the longest pole.

For behind-the-meter systems doing peak shaving and solar self-consumption, simple payback in 2026 typically falls between 6 and 8 years, faster where red-band DUoS exposure or solar surplus is high. We model it from your half-hourly data and share the full spreadsheet so your finance team can stress-test it. We treat any frequency-response or Balancing Mechanism income as upside, not the foundation of the case.

Yes, with an islanding or UPS-grade design. A battery can ride through grid outages for critical loads, cold chain, data, life-safety, or process equipment, cleaner and quieter than a diesel standby generator, and it can stack daily arbitrage value the rest of the time. Islanding requires anti-islanding protection compliant with G99, a transfer/changeover arrangement to BS 7671, and careful sizing of the critical-load circuit. We design the resilience scope around your specific must-run loads.

Carefully, the 0% VAT relief (since 1 February 2024, covering standalone retrofit batteries connected to the grid) applies to residential accommodation and buildings used solely for a relevant charitable purpose, not general commercial premises. It runs to 31 March 2027 and is then set to move to 5%. So a charity-occupied building or residential-portfolio site may qualify; a standard factory or warehouse will not. Always confirm the building's VAT status with your accountant.

Storage can earn from NESO frequency-response services (Dynamic Containment, Moderation, Regulation), the Balancing Mechanism, the Capacity Market, and wholesale trading, with revenue stacking across Dynamic Containment and the Balancing Mechanism now permitted. However, frequency-response prices have become volatile and saturated, so for behind-the-meter sites we treat grid-services income as upside only. It matters far more for grid-scale, developer-led assets with the right metering and market accreditation.

Quality LFP commercial cells are typically warranted for around 6,000-10,000 cycles or 10 years to roughly 70% retained capacity, with real-world life often longer. We size with end-of-life capacity in mind so the system still meets your peak target late in life, and plan augmentation (adding cells) where it makes sense. The warranted cycle count, throughput, and degradation curve are stated in every proposal.

LFP (lithium iron phosphate) is the standard for commercial stationary storage: longer cycle life, much greater thermal stability, no cobalt, and a far lower thermal-runaway risk, at the cost of slightly lower energy density. NMC (nickel manganese cobalt) is denser but less thermally stable and is now rare in new UK commercial BESS for safety and lifecycle reasons. We specify LFP for almost all commercial installs.

Yes, and it is often the cheapest enabler. Rapid and ultra-rapid chargers create short, severe demand spikes that can trigger an expensive grid upgrade. A battery buffers those spikes, charging off-peak and from on-site solar, then discharging into the charging peaks, letting you install more chargers on your existing connection and deploy far faster than DNO reinforcement allows. We design the storage and charging infrastructure together.

From contract to commissioning, typically 4-9 months for behind-the-meter systems, with physical installation of 1-6 weeks once on site. The long pole is almost always the DNO: G99 study and connection timescales can run 3-18 months depending on network capacity. We submit the G99 application alongside the survey so the clock starts immediately, and use G100 limitation where it lets the project proceed sooner. Grid-scale projects run 18 months to several years including planning.

Behind-the-meter enclosures on an existing commercial site are often permitted development or a minor application, subject to size, siting, listed-building and conservation-area constraints. Larger standalone and grid-scale BESS need full planning permission, an Environmental Impact Assessment above the relevant thresholds, and fire-and-rescue-service consultation under NFCC grid-scale guidance, with attention to separation distances, firefighting access, and noise. We confirm the planning route in the feasibility study.

Through a planned O&M contract: remote 24/7 monitoring with automated alerts, periodic electrical inspection, firmware updates, thermal-management checks, and cell-balancing oversight via the battery management system. Most clients sign a 10-year-plus O&M agreement aligned to the cell warranty. Software-led optimisation (choosing when to charge/discharge against tariffs and DUoS bands) is usually included so the system keeps capturing maximum value as prices move.