Re:Isn't - (Score 2, Informative)

Actually, it's because of thermodynamics that H2 has some promise. Take natural gas as a fuel source: if you burn it in a heat engine (car engine), you are limited to a maximum heat engine efficiency of around 20-30%. That is, 20% of the energy moves your car, the other 80% goes out the radiator. Heat engines are limited in output by something called Carnot efficiency. For a car, it might be 30%. But, fuel cell are NOT Carnot limited. It is still bound by thermodynamic rules of course, but it is a chemical reaction which has an upper efficiency much higher, like around 60-70%. So, the promise is to take a fossil fuel like natural gas, extract the hydrogen with an efficient process (like steam methane reforming) and then use it in an efficient fuel cell. That's the promise. Personally, as the previsous author, I have my doubts about future of fuel cells. Just too damn expensive.