There is a broad categorisation of energy, that does not seem to be considered in the current discussions about alternative-fuels - STATIONARY-ENERGY and MOBILE-ENERGY.

Stationary-energy can come from fossil-fuels, or any of the cleaner methods under consideration.  For argument's sake, lets assume that S-E is far more efficient [ and environmentally-friendly ] than M-E.  Then, it would be logical to think in terms of converting S-E to M-E.  The obvious choice here is to produce hydrogen as a source of M-E.  This has been trialled, very successfully, in Europe.  The show-stopper is "distribution".

My idea [ which may be original, or it may not ] is to design and build a practical, portable hydrogen-generator, to be used at the gas-station level or even in the home.  While the production of hydrogen [ and oxgen ] is hardly rocket-science, a serious effort will still be required to make the process portable, economic, efficient, and SAFE.