Plug-in solar with a battery in the UK

Who benefits from a battery?

A battery suits you if you want to use solar electricity that would otherwise go unused at home. In the calculator’s London example, a 1 kWh battery raises the share used at home from 63% to 93%, with annual savings rising from £99 to £140.

Extra storage is less compelling if you already use most solar electricity during the day. Even in that London example, increasing storage to 2 kWh raises annual savings to £150 rather than £140; compare those results with the battery’s purchase price, rather than choosing capacity alone.

Check compliance before capacity

The exact system’s compliance matters more than its battery capacity. SI 2026/848, in effect since 27 August 2026, defines a plug-in microgenerator with a maximum rated output of 800 W AC; DESNZ says only devices complying with the Interim Product Specification can be sold and plugged in under the amended plug rules.

The battery product cards include equipment that is not on the ENA plug-in solar register. EcoFlow STREAM Ultra X has 3.84 kWh storage and output up to 2,300 W AC, with no panels included; its official-store price was £1,299, checked 14 October 2026. Those specifications do not establish compliance as an 800 W AC plug-in solar device.

Zendure SolarFlow 2400 AC+ and SolarFlow 2400 Pro each have 2.4 kWh storage, output up to 2,400 W AC and no panels included. Their official-store prices were £899 and £1,099 respectively, checked 14 October 2026; neither was on the register, although the seller names ENA G98. Use the UK kit comparison to distinguish registered solar kits from these battery products.

What the calculator gives

The calculator gives higher annual savings with storage, but smaller gains as capacity increases. The comparison shown here covers 0 kWh, 1 kWh and 2 kWh batteries with an 800 W kit and a 164 W base load.

For London SW postcodes, the calculator gives 596 kWh annual production from a south-facing vertical kit, with 374 kWh used at home without storage. Across 0 kWh, 1 kWh and 2 kWh batteries, the shares used at home are 63%, 93% and 99%, and annual savings are £99, £140 and £150 respectively.

For Manchester, the calculator gives 523 kWh annual production and 341 kWh used at home without storage. Across the same battery capacities, home use is 65%, 92% and 99%, with annual savings of £90, £123 and £131.

For Glasgow, the calculator gives 503 kWh annual production and 319 kWh used at home without storage. Home use rises from 64% to 93% to 99%, with annual savings of £84, £120 and £127. These examples assume no export payment; use the calculator to compare your own location and electricity use.