(AOL Autos) -- At the dawn of the automobile age, gasoline was the up-and-coming "alternative fuel" -- vying with electric batteries and steam power.

Gas ultimately won out, of course.


But now that we're running out of distilled dinosaur juice -- or at the very least, getting sick of being at the mercy of OPEC -- a variety of 21st century alternatives to gasoline are entering the pipeline (so to speak).