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EERC Update

A Road Map for Biofuels Research
By Chris J. Zygarlicke
As the dust settles following the 23rd Annual International Fuel Ethanol Workshop and Expo in St. Louis, new discussions have emerged concerning the future of ethanol and other biofuels. The key to many of these discussions is the debate about starch-based ethanol, lignocellulosic ethanol and biodiesel-based fuels. Opinions from politicians, scientists, investors and developers range broadly on the percentage of U.S. transportation fuel that can be replaced by biofuels.

Currently, ethanol accounts for about 4 percent of the fuel used in the United States transportation sector. Most of that figure relates to corn- or starch-based ethanol. With over 200 ethanol plants slated to be operating in three years or so, ethanol will soon make up 8 percent or more of our gasoline consumption. However, the future beyond that is unclear. To achieve significant levels of total biofuel consumption, meaning ethanol and biodiesel production, more attention-a lot more attention-must be paid to biomass.

The Energy & Environmental Research Center (EERC) sees a great need for investment in applied research and development to improve all aspects of field-to-wheels efficiency in biofuels. Replacing a significant portion of petroleum-derived transportation fuels with domestic renewable alternatives from biomass will require new, innovative pathways that 1) compete economically with petroleum and 2) maximize the fuel production capacity of U.S. agricultural lands, which means achieving a maximum "vehicle miles traveled" per acre. This involves a paradigm shift in thinking and conducting research on both the development of biofuels and how the fuels are consumed. In other words, we must tie together how we convert biomass-by fermentation or thermochemical means-with how we convert the products into propulsion-spark- and compression-ignition engines, turbines or fuel cells.

Presently, it is the EERC's belief that there are six primary options for the future of biomass- or lignocellulose-based biofuel production:

1. Enzyme hydrolysis of biomass followed by conventional fermentation of the sugars made available from the cellulose to ethanol

2. Thermal gasification of the biomass to convert it to mostly volatile carbon monoxide, hydrogen, carbon dioxide and methane, followed by fermentation of this mixture to ethanol

3. Thermal gasification of the biomass followed by nonfermentive alcohol synthesis and mixed-alcohol production

4. Thermal gasification of the biomass followed by Fischer–Tropsch conversion to distillates or "green diesel"

5. Thermal gasification of the biomass followed by methanol synthesis, dehydration and catalytic conversion to dimethyl ether, a higher-reaction-temperature, higher-cetane compound that is an excellent diesel fuel substitute, and

6. Pyrolysis conversion of biomass to bio-oil followed by hydrogenation and conversion to distillates or "green diesel."

In next month's column, we will expand on the advantages and disadvantages of these six pathways to conversion of biomass to transportation fuels. The United States is definitely at a crossroads for determining in which pathways to invest for new, cutting-edge technologies for converting biomass to fuels. It will be exciting to watch how technology breakthroughs, economics, politics and public support determine the course of these pathways.

Chris J. Zygarlicke is deputy associate director for research at the EERC in Grand Forks, N.D. He can be reached at czygarlicke@undeerc.org or (701) 777-5123.
 

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