Combustion engines have over 100 years of wast R&D and real world usage behind them. We already have the infrastructure to move their fuel all over the world in wast quantities.
This means I would not be surprised if we start using solar, wind, and nuclear power to generate gasoline, and most future cars become very clean running gasoline/electric hybrids.
From Wikipedia (http://en.wikipedia.org/wiki/Hydrogen_economy): Liquefied hydrogen has lower energy density by volume than gasoline by approximately a factor of four, because of the low density of liquid hydrogen — there is actually more hydrogen in a liter of gasoline (116 grams) than there is in a liter of pure liquid hydrogen (71 grams).
This means I would not be surprised if we start using solar, wind, and nuclear power to generate gasoline, and most future cars become very clean running gasoline/electric hybrids.
From Wikipedia (http://en.wikipedia.org/wiki/Hydrogen_economy): Liquefied hydrogen has lower energy density by volume than gasoline by approximately a factor of four, because of the low density of liquid hydrogen — there is actually more hydrogen in a liter of gasoline (116 grams) than there is in a liter of pure liquid hydrogen (71 grams).