Ted B.
It wouldn't be too difficult to convert the existing petro-fuel infrastructure to accomodate a different liquid fuel, say alcohol, should improvements be made to the production of alcohol to the point where it was a viable energy source. An alcohol-eating fuel cell might offer some real promise, as even though the energy density of alcohol is much lower than current petrofuels, the theoretical efficiency of a fuel cell-electric motor combination is higher than that of an IC engine-mechanical drive. Should that technology be developed, and there *are* people working on it, I'm sure the next big project would be a push towards developing a renewable source of alcohol with a positive energy balance. (I'd be surprised if there wasn't already R&D going on in that respect as well.) A nice side benefit is that existing petro-fuel vehicles can be converted to run on alcohol, gasoline, or a mix of the two (and in fact such vehicles are already commercially available.)
Likewise, pure electric production and transmission is a well understood discipline; should that turn out to be the way to go, it would simply be a matter of adding more transmission capability and power plants. Also might become more common for homeowners to have home windmills or solar panels.
The infrastructure required for the safe transport or distribution of H2 however would be completely different from anything currently done on a large scale...
nate
