Battery Storage in 2026: Is It Worth Adding to Your Solar Panels?

Adding a battery to your solar panels sounds like a no-brainer - store what you generate during the day, use it at night. But batteries aren't free, and the economics depend on your specific situation.

What does a battery cost?

Battery prices have been falling, but they're still a significant investment:

• 5kWh battery: £2,500 - £3,500
• 10kWh battery: £4,500 - £6,500


• 13.5kWh (Tesla Powerwall): £6,500 - £8,500

These are fitted prices. VAT on batteries installed alongside solar panels remains at 0%.

The self-consumption argument

Without a battery, a typical household uses only 30-50% of the solar electricity they generate. The rest gets exported at 12-15p/kWh via the Smart Export Guarantee.

With a battery, self-consumption jumps to 70-85%. Instead of exporting at 12p and buying back at 24p, you're using your own stored electricity.

For a 4kW solar system generating roughly 3,800 kWh/year:

• Without battery: Self-consume 1,500 kWh (save £360), export 2,300 kWh (earn £276). Total: £636/year.
• With 10kWh battery: Self-consume 2,900 kWh (save £696), export 900 kWh (earn £108). Total: £804/year.

The battery adds about £168/year. At a cost of £5,500, that's a 33-year payback on the battery alone - longer than most warranties.

When batteries do make sense

The picture improves significantly with a time-of-use tariff. Some energy tariffs offer electricity at 7-10p/kWh overnight and 30p+ at peak. With a smart battery, you charge cheaply overnight and use stored electricity during peak hours.

This "tariff arbitrage" can add £300-500/year, bringing the payback down to 8-12 years - much more reasonable.

Our recommendation

If you're installing solar panels from scratch, get quotes both with and without a battery. The marginal cost of adding one during installation is lower than retrofitting later.

A battery makes most sense when you're on a time-of-use tariff, your self-consumption is below 40%, you value power resilience, or you're planning an EV charger.

For help sizing, check our battery sizing guide. And compare quotes from multiple installers - prices vary substantially. We also looked at how solar and battery bundles work together for maximum savings.