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

educed. As part of the RFS rulemaking, EPA is estimating the energy security effects of
reduced oil use due to the expanded use of renewable fuel. However, these analyses will
not be available until the final rule.
4. Greenhouse Gases And Fossil Fuel Consumption
There has been considerable interest in the impacts of fuel programs on
greenhouse gases and fossil fuel consumption. Therefore, in this proposed rulemaking
we have undertaken an analysis of the greenhouse gas and fossil fuel consumption
impacts of a transition to greater renewable fuel use. This is the first analysis of its kind
in a major rule, and as such it may guide future work in this area.
As a result of the transition to greater renewable fuel use, some petroleum-based
gasoline and diesel will be directly replaced by renewable fuels. Therefore, consumption
of petroleum-based fuels will be lower than it would be if no renewable fuels were used
in transportation vehicles. However, a true measure of the impact of greater use of
renewable fuels on petroleum use, and indeed on the use of all fossil fuels, accounts not
only for the direct use and combustion of the finished fuel in a vehicle or engine, but also
includes the petroleum use associated with production and transportation of that fuel. For
instance, fossil fuels are used in producing and transporting renewable feedstocks such as
plants or animal byproducts, in converting the renewable feedstocks into renewable fuel,
and in transporting and blending the renewable fuels for consumption as motor vehicle
fuel. Likewise, fossil fuels are used in the production and transportation of petroleum
and its finished products. In order to estimate the true impacts of increases in renewable
fuel use on fossil fuel use, we must take these steps into account. Such analyses are
termed lifecycle analyses.
We compared the lifecycle impacts of renewable fuels to the petroleum-based
gasoline and diesel fuels that they replace. This analysis allowed us to estimate not only
the overall impacts of renewable fuel use on petroleum use, but also on emissions of
greenhouse gases such as carbon dioxide from all fossil fuels. Based on a comparison to
the 2004 base fuel, we estimated that the increased use of renewable fuels will reduce
petroleum consumption by about 1.0 to 1.6 percent in the transportation sector in 2012.
This is equivalent to 2.3 - 3.9 billion gallons of petroleum in 2012. We also estimated
that greenhouse gases from the transportation sector will be reduced by about 0.4 - 0.6
percent, equivalent to about 9 - 14 million tons. These reductions are projected to
continue to increase in the future as crude oil prices are expected to continue to provide
the stimulus for greater use of renewable fuels beyond 2012. These greenhouse gas
emission reductions are also dominated by the forecast that the majority of the future
ethanol use will be produced from corn. If advances in cellulosic technology allow its
use to exceed the levels assumed in our analysis, then even greater greenhouse gas
reductions would result. 5
5 Cellulosic ethanol is estimated to provide a comparable petroleum displacement as corn derived ethanol
on a per gallon basis, though the impacts on total energy and greenhouse gas emissions differ.
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