Hey Racer, thanks for the link to the GM Hydrogen Fuel Cell Concept car. Finally got time to watch it. That's a pretty slick design.
What GM built was a Liquidified Hydrogen Fuel Cell powered car. The story was a little misleading. You can get Hydrogen from water, but currently they predominately get hydrogen from Natural Gas (methane CH4). Since it costs less. You use a chemical process to disassociate the hydrogen from the carbon, which results in lots of carbon dioxide and a big tank of hydrogen gas. You also have to figure out what to do with all that carbon dioxide, or the greenies will hate you. Methane is a fossil fuel also, the result of decomposition of plant/animal matter in the absence of oxygen.
Getting hydrogen from water though, requires huge amounts of electricity. The process is called Electrolysis. In the end, you get a lot less energy out of the hydrogen, than it took to make it. 30% to 50% less.
Electrolysis
By the way, that car runs on liquidified hydrogen gas, hugely expensive to produce since you have to turn a gas into a liquid. Notice it doesn't have huge 5000psi storage tanks.
Fuel cells are neat, they don't burn the gas they combine hydrogen with oxygen (makes water), through a super high tech membrane, releasing an electron, that is captured and then drives an electric motor. Fuel cells are actually more efficient at making power than burning hydrogen directly.
Hydrogen Fuel Cell Cars
Making hydrogen from water with electrolysis takes huge amounts of electricity. The power to do this has to be made somewhere. That'd be coal in the USA. The GM car isn't a scam, it attempt to use a fuel that can be made somewhere, and the end user can then use it without producing any pollution. The manufacturer of hydrogen makes huge pollution, but that can be controlled by the government. The whole hydrogen economy would work, but there's better ways to run cars. Probably work good in a communist society.
all this time I had you figured for a dumbazz 
