Coal is going to fade rapidly with heavy tax disincentives and
incentives that favor Solar/Hydro/Geo and I expect we will also build
at least some new Nuclear plants.  Nuclear isn't popular, but it's
better than the coal alternative and will help get us off the Oil
(blood) coming out of the Middle East that's drained our treasure and
severly weakened our national defense.  And there are certainly
cleaner sources like Natural Gas, which we have as much of as Coal and
I plan to invest in those companies like CHK and XTO, for example, who
will be profiting from that trend.  In China, Natural Gas conversions
are being done by the millions for their cars and there are investment
opportunities there too with SNEN and CHNG.

Watch Denmark and Israel.  An Island nation and a virutal island
nation as examples where electric vehicles are about to revolutionize
the market in a couple of years.  You can only drive so far and both
countries are happy to avoid oil based energy use.  It's going to take
longer in the USA and Natural Gas may be an option, but I expect we'll
drag out the oil consuming gas hogs for some time with electrics with
better battery technology taking some time.

Hydrogen?  Maybe.  That's an entirely different infrastructure that
would have to be built whereas the electric grid already exists and
will only need some bolstering, so I think electricity is going to be
the vehicular energy currency of the few decades and the focus will be
on just what you mentioned...cleaner sources for our electricity that
powers our homes, businesses and soon, our vehicles.

Happy investing!  Or smoking.  :)