I think the fuel cell might be one of our transportation fuel answers, in a distributed fashion. However, now, I think the MoU (Masters of the Universe) see petrochemicals as the hydrogen feedstock, hence the Bush admin's subsidy for this particular technology.
However, Prof Nocera, MIT, has apparently found cheap, common catalysts that make hydrolyzing (using solar, wind, etc.) oxygen and hydrogen from water, of any quality, at ambient temperature, without pH extremes, and cheap, a reality. (First models were made from pvc pipes.) This provides a way to store the inconsistent solar and wind energy without batteries.
His goal is distributed (residential) hydrogen production and storage, that will feed the fuel cell to generate electricity for home, car, etc. He has formed a company, Suncatalytix, to get the $$ to commercialize the units.
BTW, this is a kind of imitation of photosynthesis
And I understand there is work being done now to make fuel cells more economical, i.e, using something other that platinum membranes.
Here he is at PopTech -
http://poptech.org/danielnocera/ And as of 4/2011
http://www.climatecentral.org/blogs/nocera-takes-solar-energy-for-the-masses-one-step-further I hope the great scientific and engineering minds in this forum can check it out and explain it better than I have

And that this is not off topic or should be in another thread.