Originally Posted By: Garak
Aside from logistical concerns about transporting and distributing hydrogen, the real concern is the law of thermodynamics. Propane, natural gas, and crude oil are all actual sources of energy we can find, refine, and distribute, expending less energy to get them than we get from them.
With hydrogen, though, you can't simply drill into the ground and find a deposit and fill up tanks. You have to be able to get it from somewhere (i.e. water) in an efficient, effective, and feasible manner.
As for LPG, I couldn't agree more. I've run many vehicles on that in years past, and it was probably the least problematic of the alternative fuels.
Yes, from hydrocarbons. Steam reformation yields 3 miles of hydrogen for one mole of methane, and if done right to make carbon monoxide, then it can get shifted to produce another mole of hydrogen per mole of carbon monoxide.
This yields a pretty high overall efficiency on the basis of heating value in vs out. The question then is if there are efficiencies to be had vs internal combustion of hydrocarbons. Fuel cells are not constrained by Carnot, so the solid state conversion is far more efficient.