Arguments about the pros and cons of biofuels such as
ethanol have gone on for many years. The latest debates pertain to whether
proposals to limit the ramp-up of the Renewable Fuel Standard (RFS) would
result in higher or lower emissions of carbon dioxide (CO2) and other
climate-disrupting greenhouse gases.
This week Environmental
Protective Agency (EPA ) Administrator Gina McCarthy tweeted the benefits of
biofuels:
and signaled the
agency's intent to further raise the RFS volumetric mandate:
At the crux of the issue is the ability to determine the
“carbon footprint” of biofuels using computer models. These models, such as the
GREET model developed by Argonne National Laboratory in Illinois, use what are
known as lifecycle assessment techniques that claim to account for all of the
emissions associated with producing and using a fuel. GREET modeling is the
basis for assertions by BIO (the Biotechnology Industry
Organization) that the RFS has reduced carbon emissions since it was passed in
2005. It is also the basis for the recent University of Illinois statement that the
proposed RFS limits would increase CO2 emissions as much as putting nearly one
million more cars on the road.