Battery Storage
Solar Canopy Battery Storage
A solar canopy generates electricity during daylight hours. Battery storage extends that value into evenings, weekends, and periods of high grid cost — increasing the proportion of your electricity that comes from the sun rather than the grid.
Why add battery storage to a solar canopy?
A solar canopy without battery storage is already a strong investment. Adding battery storage improves the financial case by increasing the proportion of generated electricity that displaces grid purchases rather than being exported at a lower rate.
The fundamental economics: electricity you generate and self-consume saves you 22-28p/kWh. Electricity you export earns you 4-15p/kWh under the Smart Export Guarantee (SEG). Battery storage converts exports (at 4-15p) into self-consumption (at 22-28p). The difference — 7-24p per kWh shifted — is the economic value of storage.
When does storage add most value?
Battery storage adds most value to sites with a mismatch between generation and consumption profiles — specifically, where solar generation peaks at different times from electricity demand. Examples include:
- Retail parks and supermarkets: High evening demand after solar generation falls. Storage shifts afternoon solar generation into the evening retail peak.
- Schools and universities: Low weekend demand means weekend solar generation is largely wasted without storage.
- Hotels: Evening and overnight demand from heating, lighting, and HVAC cannot currently be met by solar alone. Storage bridges the gap.
- EV-heavy sites: Large rapid chargers cause demand spikes. Battery storage buffers these and reduces maximum demand charges.
When does storage add less value?
Sites where electricity demand closely matches solar generation hours — primarily large industrial sites operating continuous 06:00-18:00 processes — have high direct self-consumption without storage. Adding storage has lower marginal benefit, and capital is better deployed in additional solar panel capacity first.
Battery storage: key figures
- Typical system size
- 50–500 kWh (commercial)
- Round-trip efficiency
- 92–95% (LFP chemistry)
- Cycle life (LFP)
- 4,000–6,000 cycles (10-15yr)
- Battery cost (2026)
- £200–£350/kWh installed
- Payback (standalone)
- 7–12 years
- Payback (solar + battery)
- 4–7 years combined
- Demand charge saving
- 10–30% of demand element
- Grid outage protection
- Optional islanding available
Storage sizing guide
As a starting point, size battery storage to 1-2 hours of your average evening peak demand, or 20-30% of your daily solar generation — whichever is smaller.
Four ways battery storage adds value
Store excess daytime generation
A car park canopy generates most electricity between 09:00 and 15:00. If your site uses less electricity during these hours than the panels produce — weekends, school holidays, reduced staffing — the surplus would otherwise be exported at SEG rates (4-15p/kWh). Battery storage captures this surplus and discharges it during the evening peak (16:00-20:00) when you would otherwise buy from the grid at 22-28p/kWh.
Shift peak demand charges
Sites on half-hourly metered supply pay a maximum demand charge (MOP/MAP) based on the highest 30-minute consumption period in the billing period. Discharging battery storage during peak periods reduces your measured maximum demand — cutting the demand element of your bill. For sites with demand above 100 kW, demand charge reduction can contribute as much to the financial case as energy bill savings.
EV charging buffer capacity
Large EV chargers (50-150 kW DC rapid chargers) cause demand spikes that can trip demand charge thresholds or exceed contracted grid capacity. Battery storage buffers these spikes — the charger draws from the battery during peak EV charging periods, which recharges from the solar panels during the day. This allows faster EV chargers to be installed without reinforcing the grid connection.
Grid outage resilience
With suitable inverter configuration, a solar canopy with battery storage can provide limited islanding capability during grid outages — keeping critical loads (server rooms, refrigeration, security systems) operational. This requires specific inverter and switchgear design. Full islanding is available for sites requiring full resilience.
Battery technology options
| Chemistry | Capacity range | Cycle life | Safety | Best for |
|---|---|---|---|---|
| LFP (Lithium Iron Phosphate) | 100–5,000 kWh | 4,000–6,000 | Excellent | Standard commercial BESS. Safest chemistry, lowest degradation. |
| NMC (Nickel Manganese Cobalt) | 50–1,000 kWh | 2,000–3,500 | Good | Higher energy density where space is constrained. |
| VRLA / Lead Acid | 50–500 kWh | 500–1,200 | Very good | Lower cost, shorter life. Suitable for secondary backup roles. |
We specify LFP (Lithium Iron Phosphate) as standard for all commercial solar canopy battery storage applications.
Integration with solar canopy and EV charging
Solar + Battery
The most common configuration. String inverters from the canopy feed the battery via a hybrid inverter or separate battery inverter. The battery management system (BMS) determines the optimal charge/discharge schedule based on time-of-use tariff data and forecast solar generation.
Solar + Battery + EV
The complete integrated system. Solar panels charge the battery during the day. The battery discharges to EV chargers during peak charging periods (typically 07:00-09:00 and 17:00-20:00), reducing demand spikes and grid import. Smart load management balances all three assets in real time.
Battery only (retrofit)
Battery storage can be retrofitted to an existing solar canopy. We assess the existing inverter configuration — some string inverters are battery-compatible via AC coupling, others require a separate battery inverter. All retrofit designs are compatible with the site's existing DNO connection.
Add battery storage to your solar canopy design
We model battery storage alongside the solar canopy from the start of the feasibility study — optimising the storage size for your consumption profile and electricity tariff. No additional charge.
Request free feasibility with battery storage