Penn State researchers have developed a way to convert waste water into hydrogen more efficiently and faster through the use of microbes. Hydrogen has continued to be viewed as the wonder fuel but many are extremely critical due to the process it takes to make it and then the safety of storing it. Of course, everyone cites a single blimp crashing and burning (ie, the Hindenburg). While I admit I don’t want my car to be a giant ball of fire in an accident, it can also happen with gasoline (though gas isn’t as volatile, its bad enough).
I personally would love my car to emit water when I drive. I’d feel pretty good about myself and the environment.