Wolf,

You really have to think of petrochemicals as eons of solar energy converted to hydrocarbons.
In a sense we're taking the "cream" after nature and history has done the work of milking the cow.

IMO, Until cellulosic ethanol gets online in a big way it(ethanol)'s a net loss without the subsidy that we ALL are paying for.
Tractors, fertilizer, herbaside, combines, and the heat to distill it.

OK, now I opened my mouth.
I'm waiting for some one to point out how far I have my foot in............