What might work along the same line, is home-based battery systems tied to home-based generation systems. Homeowners could size their PV or wind or methane-digester generating systems and battery backup with grid-buffering capabilities. Coupling the storage/buffering system with a generating capacity, to me, makes more sense than using an auto which is only a consumer of energy and not a producer.

There is another piece to the home system--heat. You can use the excess generator heat for water and space heating. With the auto, that heat dissipates into the atmosphere.

That's why I suggested domestic cogenerators to charge batteries for (PH)EVs.  You can multiply the benefits that way.