When battery storage adds value
Battery makes sense when: PV generation profile mismatches load profile (e.g. shift-pattern operations); evening shift would otherwise import expensive grid electricity; SEG export tariff is low (5p/kWh) vs grid retail (22p/kWh); EV vehicle charging during evening or overnight; grid services revenue available (Capacity Market, FFR).
When battery storage doesn't add value
Battery is rarely economic for: continuous 24/7 operations (cold chain, data centre) where self-consumption is already 90%+; high SEG tariff environments where export economics are good; small systems below 500 kW PV where capex is dominated by transaction cost.
Sizing and economics
Typical battery sizing: 250-500 kWh for 500 kW PV install. Capex: £350-£550 per kWh battery in 2026. Payback: 6-9 years. 25-year IRR: 12-18%. We model with and without battery in every proposal.
Grid services revenue
Battery can earn grid services revenue (Capacity Market, Firm Frequency Response, Dynamic Containment). Typical revenue: £30-£80/kW/year. Adds material additional revenue stream — established grid services aggregators (Limejump, Flexitricity) handle participation.
Common questions
Should we add battery to our warehouse PV?
Depends on load profile. Continuous 24/7 operations: usually no. Shift-pattern with evening downtime: usually yes. EV vehicle fleet charging: usually yes. We model with and without battery in every proposal.
How much does warehouse battery storage cost?
£350-£550 per kWh installed in 2026 for utility-scale lithium-ion. 250-500 kWh is typical sizing for 500 kW PV install. Total capex £90k-£275k. Payback 6-9 years.