@TJefferson256: Ethanol is not naturally harmful to the environment, it's just the way it is produced now that is harmful to the environment. Not only is it very ineffective since a rather low amount can be gained from an acre of land, but also is extra nitrous oxide emitted due to fertilisers used to grow the corn and to top it all off, in as good as all ethanol producing plants, they use coal to generate the heat needed to make ethanol. That's why it's so bad for the environment.

Ethanol from cellulose has none of these problems. Cellulose is everything, from fallen leaves in the fall to wood waste gathered from forests to grass waste that comes around after mowing the lawn. Of course, on a large scale, you will need extra "cellulose plantations" to meet the demand which again brings the problem with the nitrous oxide, but atleast you don't need to heat it up to something around 100°C to get the ethanol - like Caltex said you can use bacteria to do it, and further you get a much larger amount of ethanol out of it per acre.

Reykjavik, the capital of Iceland, has already been using some hydrogen powered buses for years now as a part of a European research program on Hydrogen, and eventhough they had problems in the start nowadays the buses work very well. Research - Environment - Hydrogen-powered buses in action

__________________