Regulation of Fuels and Fuel Additives: Renewable Fuel Standard ...

First, doing so could create an incentive for obligated parties to choose renewable fuels
having a greater ability to reduce fossil fuel use or resulting emissions, since such
renewable fuels would have higher Equivalence Values and thus greater value in terms of
compliance with the RFS requirements. The preferential demand for renewable fuels
having higher Equivalence Values could in turn spur additional growth in production of
these renewable fuels. Second, using lifecycle analyses as the basis for Equivalence
Values could orient the RFS program more explicitly towards reducing fossil fuel use or
emissions.
At the same time, the use of lifecycle analyses to establish the Equivalence Values
for different renewable fuels also raises a number of issues. For instance, lifecycle
analyses can be conducted using several different metrics, including total fossil fuel
consumed, petroleum energy consumed, criteria pollutant emissions (e.g., VOC, NOx,
PM) carbon dioxide emissions, or greenhouse gas emissions. Each metric would result in
a different Equivalence Value for the same renewable fuel. At the present time there is
no consensus on which metric would be most appropriate for this purpose.
There is also no consensus on the approach to lifecycle analyses themselves.
Although we have chosen to base our lifecycle analyses on Argonne National
Laboratory's GREET model for the reasons described in Section IX, there are a variety of
other lifecycle models and analyses available. The choice of model inputs and
assumptions all have a bearing on the results of lifecycle analyses, and many of these
assumptions remain the subject of debate among researchers. Lifecycle analyses must
also contend with the fact that the inputs and assumptions generally represent industrywide
averages even though energy consumed and emissions generated can vary widely
from one facility or process to another. There currently exists no single body,
governmental or otherwise, that has organized a comprehensive dialogue among
stakeholders about the appropriate tools and assumptions behind any lifecycle analyses
with the goal of coming to agreement.
Another issue to using lifecycle analyses as the basis for Equivalence Values
pertains to the ultimate impact that the RFS program would have on petroleum use, fossil
fuel use, criteria pollutant emissions, and/or emissions of GHGs. With a fixed volume of
renewable fuel required under the RFS program, any renewable fuel with an Equivalence
Value greater than 1.0 would necessarily mean that fewer actual gallons would be needed
to meet the RFS standard. Thus, the advantage per gallon may be offset with fewer
overall gallons, resulting in no overall additional benefit unless the RFS standard was
simultaneously adjusted.
Finally, lifecycle analyses of different renewable fuels are likely to change over
time as farming practices and process technologies evolve. Significant changes would
necessitate corresponding changes the RFS program to adjust the Equivalence Values on
an ongoing basis which would add uncertainty into the long-term RIN market.
We request comment on all issues associated with the use of lifecycle analyses in
establishing the Equivalence Values for different renewable fuels for the RFS program.
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