Hydrogen is only a "battery" -- storage. There is always some energy
lost during transfers (heat, in fact, usually, although noise is wasted
energy, too). Using the electricity to charge a battery or run a train
would probably be at least as efficient.
In the US, we have short supply on electricity, and most of it is
generated by coal or nuke (although natural gas is catching up fast).
PV is fine, except it's very expensive and there is a huge energy
requirement for making the high-purity silicone wafers for the cells...
It's all circular and all in there together, you can't do "accounting"
with energy -- actually you can't do it with money, either, although
you can pretend (aka Enron).
Final answer is that without petroleum (cheap petroleum at that), the
world will be a different place.
As for ethanol, it takes nearly the BTU content of the final product to
distill it out of the fermentation solution, and I don't know of any
alternative -- you can save a bunch by re-cycling the heat, but that
take quite a bit of engineering and isn't cheap. There is a local (S.
Illinois) ethanol plant being widely talked up as the "way of the
future" -- burns 300 ton of coal a day for less than 600 ton of
ethanol.....
Peter
