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

elatively small fraction of the total ethanol demand, the sensitivity of the overall analysis to
this assumption is also very small. Based on these factors, we have assigned starch ethanol
made using this cellulosic criteria the same cost as ethanol produced from corn using
conventional means.
b. Cellulosic Ethanol
In 1999, the National Renewable Energy Laboratory (NREL) published a report
outlining its work with the USDA to design a computer model of a plant to produce
ethanol from hard-wood chips. 69 Although the model was originally prepared for
hardwood chips, it was meant to serve as a modifiable-platform for ongoing research
using cellulosic biomass as feedstock to produce ethanol. Their long-term plan was that
various indices, costs, technologies, and other factors would be regularly updated.
NREL and USDA used a modified version of the model to compare the cost of
using corn-grain with the cost of using corn stover to produce ethanol. We used the corn
stover model from the second NREL/USDA study for the analysis for this proposed rule.
Because there were no operating plants that could potentially provide real world process
design, construction, and operating data for processing cellulosic ethanol, NREL had
considered modeling the plant based on assumptions associated with a first-of-a-kind or
pioneer plant. The literature indicates that such models often underestimate actual costs
since the high performance assumed for pioneer process plants is generally unrealistic.
Instead, the NREL researchers assumed that the corn stover plant was an Nth
generation plant, e.g., not a pioneer plant or first-or-its kind, built after the industry had
been sufficiently established to provide verified costs. The corn stover plant was
normalized to the corn kernel plant, e.g., placed on a similar basis. 70 It is also reasonable
to expect that the cost of cellulosic ethanol would be higher than corn ethanol because of
the complexity of the cellulose conversion process. Recently, process improvements and
advancements in corn production have considerably reduced the cost of producing corn
ethanol. We also believe it is realistic to assume that cellulose-derived ethanol process
improvements will be made and that one can likewise reasonably expect that as the
industry matures, the cost of producing ethanol from cellulose will also decrease.
69 Lignocellulosic Biomass to Ethanol Process Design and Economics Utilizing Co-Current Dilute Acid
Prehydrolysis and Enzymatic Hydrolysis Current and Futuristic Scenarios, Robert Wooley, Mark Ruth,
John Sheehan, and Kelly Ibsen, Biotechnology Center for Fuels and Chemicals Henry Majdeski and Adrian
Galvez, Delta-T Corporation; National Renewable Energy Laboratory, Golden, CO, July 1999, NREL/TP-
580-26157
70 Determining the Cost of Producing Ethanol from Corn Starch and Lignocellulosic Feedstocks; A Joint
Study Sponsored by: USDA and USDOE, October 2000 • NREL/TP-580-28893 • Andrew McAloon,
Frank Taylor, Winnie Yee, USDA, Eastern Regional Research Center Agricultural Research Service; Kelly
Ibsen, Robert Wooley, National Renewable Energy Laboratory, Biotechnology Center for Fuels and
Chemicals, 1617 Cole Boulevard, Golden, CO, 80401-3393; NREL is a USDOE Operated by Midwest
Research Institute · Battelle · Bechtel; Contract No. DE-AC36-99-GO10337.
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