Biofuel+Enviro+Impact

ideas:
 * 1) Energy used to produce biofuel
 * 2) Bi-product of biofuel production
 * 3) biofuel exhaust (does it produce pollutants)
 * 4) species variety (what happens if only a few certain crops are being mass produced in the world)

Biofuel Enviro Impact http://www.iea.org/techno/essentials2.pdf