Just saw one at "Earth Day" and talked to the owner. It is at Middle Tennessee State University and the one I saw wasn't actually the real thing. Anyway, what he has is a one stop source there at the school. He has solar panels at the side of one of the buildings that generate the electricity to charge his car. There are additional batteries for the plug in. I think he said the car could run about 24 miles on just those batteries if needed. They are just really to assist the other current batteries the Prius has. He also has a water filtration system that produces the Hydrogen for his car. He already has this engine in another car that he has been driving for a while. He is so in love with it that he won't just take it apart and put it into the Prius. The Prius will be officially presented in October.
"Hydrogen" : That's when you should have noticed the clear plastic rectal tube filled with smoke, that he was inserting. Ie, no such thing. Strike that ... there IS a company selling on-line hydrogen conversion kits ... I think the company is called, "RON-CO".