What is solar battery storage?
A solar battery stores electricity generated by your panels during the day for use in the evening and overnight. Without a battery, surplus solar electricity is exported to the grid at 4–15p/kWh. With a battery, you use that electricity yourself — saving 24.5p/kWh (the price you'd pay to buy it back).
The difference: 10–20p saved per kWh on every unit you store instead of export. On a 4kW system that's £200–£400 extra savings per year.
Battery costs in 2026
| Battery capacity | Cost (installed) | Covers |
|---|---|---|
| 3.6 kWh | £2,500–£3,500 | Evening use for 1–2 people |
| 5 kWh | £3,000–£4,500 | Evening use for 2–3 people |
| 9.5 kWh | £4,500–£6,000 | Evening + overnight for a family |
| 13.5 kWh | £6,000–£8,000 | Near full overnight coverage + EV top-up |
Popular models include the Tesla Powerwall 2 (13.5kWh, ~£7,500 installed), GivEnergy All-in-One (5–9.5kWh, £3,500–£5,500), and Solax T30 (3kWh, ~£2,500). Prices include the battery, hybrid inverter (if needed), and installation.
Is a battery worth it in Leeds?
The maths depends on how much surplus you generate and your electricity tariff. For a typical 4kW system in Leeds with 12 panels:
- Without battery: Self-consumption ~50%. Export surplus at ~8p/kWh. Annual saving: £650–£850.
- With 5kWh battery: Self-consumption ~75%. Store surplus instead of exporting. Annual saving: £850–£1,100.
- Extra saving from battery: £200–£300/year. On a £3,500 battery, payback is 10–12 years.
That's marginal. Batteries make better financial sense if you're on a time-of-use tariff (charge overnight at 7p, use during the day) or charge an electric vehicle from solar. The real benefit is energy independence — less reliance on grid electricity and protection against future price rises.
What size battery do I need?
Match the battery to your evening/overnight consumption. The average UK household uses 8–10 kWh between 4pm and 8am. A 5kWh battery covers the essential evening peak (cooking, TV, lighting). A 10kWh battery covers most of the night too.
Don't oversize. A battery that's too large never fully charges in winter and you're paying for unused capacity. For most Leeds homes with a 4kW solar system, 5–9.5kWh is the sweet spot.
The Smart Export Guarantee means surplus electricity still has value even without a battery — it's not wasted. Compare quotes from Leeds installers who can advise on the right setup.