Originally Posted by rickholio

Hydrogen is a pipe dream, probably the least likely candidate available. Reason being, it takes a LOT of energy to produce the hydrogen, and it takes hydrogen under very high pressure before it gets an energy density tolerable for use in vehicles (I believe it requires 200 atmospheres of presure to force hydrogen into a liquified state). The only advantage to hydrogen is that burning it produces nothing but heat and water... essentially you're transporting a portion of the energy originally taken to convert H2O into H2, and burning it in your car to make it go and convert it back to H2O.

Far more realistic is conversion to a pure or hybrid electric system, with centralized power generation that can take advantage of scale conversion from one power source to another (solar, wind, nuke, coal, whatever) and has a long proven and existing method of transportation (the grid, although it could sure as hell use some 'shoring up' in places).

Or maybe just getting off our fat asses and walking or biking places.

edit: Yes, chemistry purist, burning hydrogen can yield other compounds like peroxide, etc. Don't be a pedantic asshole.