BMW announced today that it's working with Germany's Beck Automation to use complete i3 battery packs as a home energy storage solution. As with other car companies getting into this business — Daimler and Tesla, notably — the idea is to store energy from renewable sources like solar so that it's available even when energy isn't being generated. It's also useful as a backup power source should traditional power fail, for example in a storm or an area with an unreliable grid.

The Munich-based automaker says that this is the first home energy storage system to use a complete vehicle battery, whereas something like Tesla Energy's Powerwall isn't built from a full Model S battery pack, for instance. The system is available in a 22 kWh or 33 kWh version, which would supply enough power to keep an average home operating for a full 24 hours, BMW says.

Importantly, BMW's system will work both with new batteries and also what it calls "2nd Life Batteries," which are used packs from i3s that have outlived their usefulness on the road but still supply enough power to be used in a home.

There's no word on when or where the Beck systems will be available, but it's likely that BMW will work directly with energy suppliers to make them available: in the US, it has worked with NextEra and PG&E for pilot programs in the past.