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Battery storage explained

Solar makes most power in the middle of the day. Many people are out then. A battery stores that power so you can use it in the evening.

Diagram of a day. In the daytime, panels fill the battery. In the evening, the battery powers the home. At night, a cheap tariff can top the battery up. DaytimeSun fills battery EveningBattery runs home NightCheap power tops up

Why not just sell it?

You can. But you get paid about 12p per unit for spare power. Buying power usually costs more than twice that. So using your own power is often worth more.

Time-of-use tariffs

Some energy firms sell cheaper power at quiet times, often at night. With a battery you can:

  1. Store spare solar power in the day.
  2. Use it when power is dear.
  3. Fill up on cheap power at night.
  4. On some tariffs, sell power back at busy times.

What does a battery cost?

Typically about £5,000 to £8,000. Batteries fitted in homes get 0% VAT until 31 March 2027. This applies even if you add one later.

Where our facts come from

Figures are typical and approximate. Last reviewed October 2026.