One problem with what is "greener" is a failure to look at the overall picture.
Different fuels produce different byproducts when burned. As an example, ethanol (or any alcohol) produces aldahydes or acetylaldahydes as the major byproduct (you don't have to believe me, ask any chemist). By contrast, the burning of gasoline does not produce aldahydes; thus they are not being controlled by the EPA. Thus, burning ethanol is "cleaner" if you compare only the pollutants currently being controlled. Kind of like banning guns, but making the carrying of hand grenades mandatory! Which is worse. Remember that frog in 7th grade science that was pickled in formaldahyde?
Diesel is the same way, although again the byproducts are different.
Lots of ink spilled without comprehensive research. Apples compared to oranges compared to lemons!
I still believe the solution is electric (this coming from a carburetor guy!).
Jon.
