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

. Ethanol Made From Any Feedstock In Facilities Run Mostly With
Biomass-Based Fuel
The definition of cellulosic biomass ethanol in the Act also provides that ethanol
made at any facility – regardless of whether cellulosic feedstock is used or not – may be
defined as cellulosic if at such facility “animal wastes or other waste materials are
digested or otherwise used to displace 90 percent or more of the fossil fuel normally used
in the production of ethanol.” The statutory language suggests that there are two
methods through which “animal and other waste materials” may be considered for
displacing fossil fuel. The first method is the digestion of animal wastes or other waste
materials. EPA proposes to interpret the term “digestion” to mean the conversion of
animal or other wastes into methane, which can then be combusted as fuel. We base our
interpretation on the practice in industry of using anaerobic digesters to break down
waste products such as manure into methane. Anaerobic digestion refers to the
breakdown of organic matter by bacteria in the absence of oxygen, and is used to treat
waste to produce renewable fuels. We note also that the digestion of animal wastes or
other waste materials to produce the fuel used at the ethanol plant does not have to occur
at the plant itself. Methane made from animal or other wastes offsite and then purchased
and used at the ethanol plant would also qualify.
The second method is suggested by the term “otherwise used” which we propose
to interpret as meaning 1) the direct combustion of the waste materials as fuel at an
ethanol plant, or 2) the use of thermal energy that itself is a waste product; e.g., waste
heat that is obtained from an off-site combustion process such as a neighboring plant that
has a furnace or boiler from which the waste heat is captured. With respect to the first
meaning, waste materials from tree farms (tops, branches, limbs, etc), or waste materials
from saw mills (sawdust, shavings and bark) as well as other vegetative waste materials
such as corn stover, or sugar cane bagasse, could be used as fuel for gasifier/boiler units
at ethanol plants, since they are waste materials and would not be used as a feedstock to
carbohydrate-based ethanol plants. Although such waste materials conceivably could be
feedstocks to a cellulosic ethanol plant, its use as a fuel at a carbohydrate based ethanol
plant does not subvert the intent of the definition. 14
Today’s regulations will require owners of ethanol plants to keep records of fuel
use to ensure compliance with and enforcement of this provision of the definition of
cellulosic ethanol. Due to potential enforcement-related problems associated with
application of this component of the definition of cellulosic ethanol to foreign facilities,
we intend for the final rule to develop compliance and enforcement related safeguards
similar to those set forth in proposed 80.1165(f), (g), (h) and (j), and with additional
14 On the other hand, wood from plants or trees that are grown as an energy crop may not qualify as a
waste-derived fuel in an ethanol facility because such wood would not qualify as waste materials under this
portion of the definition. Under the definition of renewable fuels and cellulosic biomass ethanol, however,
such wood material could serve as a feedstock in a cellulosic ethanol plant, since these definitions do not
restrict such feedstock to waste materials only.
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