Something that came up on another forum is that if you were to in fact add a "plug-in" option for the Prius, and you have a wind- or solar-powered system in your home, that you could "plug" the Prius into the battery pack system in your house that stores the solar- or wind-generated electricity.

In that event, you would have a source of power for the Prius that was virtually "free" if your home system was already paid for.

I expect some envirofan will do this sooner or later.....