As the saying goes, "Be careful what you wish for; you
might get it." This describes the current state of biofuels.
The appealing concept of biofuels is supported by well-meaning
environmental advocates, business interests, and governmental
policy, but if we don't make wise choices, then the reality may
not be all that we wished for. This article examines factors that
relate to the sustainability of the use of biofuels to partly
replace some petroleum energy sources for transportation. Key
inquiries concern first the energy and emissions balance of the use
of biofuels when compared to petroleum and, second, the broader
environmental impact of the biofuel production. One form of biofuel
in particular, cellulosic ethanol, is a strong contender for the
role as a sustainable fuel. Other forms under serious consideration
are corn-based ethanol and biodiesel. This article focuses on
ethanol as a sustainable transportation fuel.
