I think the idea is that you use some "free" source of
energy. I imagine the idea is some sort of device like a
solar power thingy that runs while you are at work making
hydrogen and storing it in a tank. Still, I doubt that
this technique would really yield much in the way of
stored energy for operating an automobile.

Biodiesel is really the way of the future. You can
get lots of it from biomass or recycled cooking oils that
are often flushed down the drain and it doesn't require
much energy to convert the raw materials to several useful
refined products of glycerine and diesel fuel. I imagine
the car of the future is a turbo-charged diesel motor
powering electric motor(s). Alcohol is just flat out
stupid as a fuel except that lots of republicans grow corn
in iowa and can't sell all of it to pigs or as syrup for
junk foods.
chris