One of the new alternative fuels that is being taken seriously is Hydrogen:
A colorless, highly flammable gaseous element, the lightest of all gases and the most abundant element in the universe, used in the production of synthetic ammonia and methanol, in petroleum refining, in the hydrogenation of organic materials, as a reducing atmosphere, in oxyhydrogen torches, and in rocket fuels.
I like the "most abundant element in the universe"! So we are not going to run out of Hydrogen anytime soon. Makes a great deal of sense to use it to power transportation right? Not according to Ed Ring from EcoWorld.com. Ed believes that Hydrogen is not the solution given the complications and the inefficiency of the technology.
Efficiency - Hydrogen is produced from something else, either electricity and water, biomass or fossil fuel. A fossil fuel source doesn't address the problem, and there isn't enough land to produce enough biomass hydrogen to meet the need. That leaves electricity and water. The problem here is that we are consuming electricity to generate hydrogen, which drives an auto fuel cell to produce electricity to run the car's electric powertrain! The end-to-end efficiency of this process is an unimpressive 40 percent.Storage - No immediate solutions for storing useful amounts of hydrogen in a car exist, and a viable commercial solution is a long way off. We're a lot closer to viable electricity storage solutions for automobiles (better batteries, ultra-capacitors. Also see "efficiency," above.)
Click to read the full article