Solar only vs Solar + battery for business
Battery storage adds capex but lifts self-consumption, protects against grid outages, and unlocks flexibility revenue. For most UK commercial sites in 2026, batteries pay back independently in 6–9 years — sometimes faster when paired with solar.
Solar only
Rooftop PV, no storage. Simplest, cheapest capex, best if daytime demand is high.
Sites with 70%+ daytime consumption (24/7 warehouses, cold storage, manufacturing) where solar generation already lands in load.
Solar + battery
PV plus lithium-ion battery. Higher capex, higher self-consumption, adds resilience and flexibility income.
Sites with mixed shifts, evening peaks (retail, hospitality), EV charging plans, or where UPS-level resilience is valuable.
Side-by-side comparison
| Attribute | Solar only | Solar + battery |
|---|---|---|
| Additional capex | £0 | £250–£450 per kWh |
| Self-consumption % | 45–70% | 75–95% |
| Grid outage protection | None (inverter trips) | Yes (with islanding) |
| Flexibility revenue (DFS/BM) | None | £40–£120 per kWh/year |
| Solar payback | 3.5–6 years | 4.5–7 years combined |
| Battery-only payback | N/A | 6–9 years standalone |
| Warranty | Panel 25 yr, inverter 10 yr | Add battery 10 yr, 70–80% retention |
Our verdict
Add a battery when: (a) daytime consumption is under 60% of annual demand, (b) EV charging or heat electrification is on the roadmap, (c) resilience matters, or (d) you're on a Time-of-Use tariff or eligible for flexibility markets. For 24/7 manufacturing and cold storage, solar-only usually still wins on capex efficiency.
Related reading
FAQ
How big should the battery be relative to the solar?
Rule of thumb: 1–2 kWh of battery per kWp of solar, sized to your average daily export volume. A 100 kWp system pairs well with a 100–200 kWh battery.
Does a battery qualify for Full Expensing?
Yes — battery storage installed with solar qualifies for 100% Full Expensing for UK limited companies from April 2023 onwards.
Request your free feasibility review
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