My concern about a plugin is where does the electricity come from to charge the battery?

If you have an insanely high electricty rate are you really saving any money?

If you have your electricity created by - *gasp* coal burning - is your carbon foot print any better than a gas only engine?

In Central Arkansas, a sole nuclear power plant creates 1/3 of the electricity. The rest is coal fired.

An alternative would be solar panels. That would require a means to boost the voltage up to the 110 VAC needed to push the charge to the battery. Again. How much do solar panels and such a voltage boost system cost the average joe?

Until electricity is cleanly and cheaply produced a plugin does not interest me.