Guide
Battery storage without solar: is it worth it in the UK?
Updated
No solar means the battery has exactly one job: buy cheap electricity at night and let you use it at peak prices. That can work. It works or fails entirely on your tariff, so here is the maths done honestly.
How a solar-free battery earns
Tariff arbitrage, nothing else. On a time-of-use tariff (Economy 7, EV tariffs, agile-style tariffs), the battery charges during the cheap window and powers the house when grid prices are high. Your saving per cycle is roughly the usable kWh you shift multiplied by the gap between your peak and off-peak unit rates. On some off-peak tariffs the cheap rate is less than half the peak rate, on a flat tariff the gap is zero and the battery earns nothing, which is the whole decision in one sentence: no time-of-use tariff, no case for a solar-free battery.
The honest maths
- The earning is capped by what you shift. A 5kWh battery can move at most about 5 usable kWh a day onto the cheap rate. If your peak/off-peak gap is, say, 15p/kWh, that is at most around 75p a day, arithmetic you should run with your own tariff's actual rates before believing any brochure.
- Bigger gaps, better case: EV owners already on cheap-overnight tariffs get the best arbitrage, and some tariffs pay for exporting at peak, which can improve the case further, check your tariff's terms rather than assuming.
- Cost side: £2,500–£4,500 installed for 5kWh (typical 2026 quotes), and standalone batteries have qualified for 0% VAT since February 2024, see the VAT relief explained.
- Payback is typically 8–12 years for home batteries, and arbitrage-only setups need a strong tariff gap to reach the front of that range. Check the battery's warranty (commonly around 10 years or a stated cycle count, check the specific product) against the payback you compute: a payback longer than the warranty is a bet, and you should see it priced as one.
When it genuinely stacks up
- You are on, or can switch to, a time-of-use tariff with a wide gap, EV drivers are the textbook case.
- Your evening use is high: the battery only earns on the kWh you actually shift.
- You value backup during outages: a real benefit, but note not every install supports powering the house off-grid, ask the installer explicitly if backup matters to you.
- You may add solar later: an AC-coupled battery works fine with panels added down the line.
If you have a roof that could take panels, price solar-plus-battery too before deciding, the combined system typically earns from both self-consumption and arbitrage, and shared install costs make the battery's share cheaper. Get both quoted and compare the actual numbers for your home.