Fuel-cycle assessment of selected bioethanol production pathways in the United States |
Nov 2006
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This work was sponsored by the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy. The report was prepared by Argonne National Laboratory to present the results of an analysis conducted, in part, for the 30×30 study in 2006.
As with other feedstocks for fuel production, the production of corn stover-based cellulosic ethanol has been the subject of many recent analyses.
In this analysis, life-cycle energy and emission impacts of corn stoverderived fuel ethanol to displace gasoline in light-duty vehicles (LDVs) in the United States was assessed by using extensive databases in the GREET model. Analysis includes:
• Fertilizer manufacturing;
• Farming machinery manufacturing;
• Corn farming;
• Applications of fertilizers, lime, and pesticide/herbicide to soil;
• Stover collection and transportation to ethanol plants;
• Ethanol production;
• Ethanol transportation; and
• Ethanol use in LDVs as E85.
Two time frames were assessed: near term (2012) and long term (2030). They estimated the energy consumption of petroleum oil and fossil energy; the emissions of greenhouse gases carbon dioxide (CO2), N2O, and methane (CH4); and the emissions of criteria pollutants carbon monoxide (CO), volatile organic compounds (VOCs), nitrogen oxides (NOx), sulfur oxides (SOx), and particulate matter with diameters smaller than 10 micrometers (PM10) during the fuel cycle. Were then compared scenarios of ethanol produced from corn grain, corn stover, and forest wood residue to gasoline.
For a given vehicle and fuel system, GREET separately calculates:
• Consumption of total energy (energy in non-renewable and renewable sources), fossil fuels (petroleum, natural gas, and coal), and petroleum;
• Emissions of CO2-equivalent greenhouse gases — primarily CO2, CH4, and N2O; and
• Emissions of five criteria pollutants: VOCs, CO, NOx, PM10, and SOx.
These criteria pollutant emissions are further separated into total and urban emissions. By incorporating available data for the collection and transportation of corn stover and for the production of cellulosic ethanol, the corn stover-to-ethanol pathway in the GREET model was added.
By: M. Wu, M. Wang, and H. Huo (Argonne National Laboratory)
