Life-cycle assessment of corn-based butanol as a potential transportation fuel

Nov 2007

Since 1995, with support primarily from the United States’ DOE Office of Energy Efficiency and Renewable Energy, Argonne has been developing the Greenhouse Gases, Regulated Emissions and Energy Use in Transportation (GREET) model. Argonne released the first version of the model — GREET 1.0 — in June 1996. GREET is a Microsoft® Excel™-based multidimensional spreadsheet model that addresses the well-to-wheels (WTW) analytical challenges associated with transportation fuels (including ethanol) and vehicle technologies. The latest version — GREET 1.7 — is capable of analyzing more than 100 transportation fuel pathways and 75 vehicle/fuel systems (Brinkman et al. 2005). The GREET model is updated frequently to reflect new feedstocks, processing technologies, fuels, and vehicle systems. 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 combined), petroleum, natural gas, and coal;
Emissions of carbon-dioxide (CO2) -equivalent GHGs — primarily CO2, methane (CH4), and nitrous oxide (N2O); and
Emissions of six criteria pollutants: VOCs, carbon monoxide (CO), nitrogen oxides (NOX), particulate matter measuring 10 micrometers or less (PM10), particulate matter measuring 2.5 micrometers or less (PM2.5), and sulphur oxides (SOX).
These criteria pollutant emissions are further separated into total and urban emissions.
This study was an attempt to evaluate the potential of the recent ABE process from a life-cycle perspective. This estimate provides a life-cycle analysis (LCA) of the production and use of corn-derived bio-butanol as transportation fuel to displace petroleum gasoline. First, an ABE process simulation model has been developed by using Aspen Plus®. They used the energy and mass balance resulting from the Aspen Plus® simulation as a basis for a life-cycle analysis of corn-based butanol production and use. They estimated the life-cycle energy and GHG emissions impacts of corn-based butanol (produced via the ABE process) when used to displace gasoline as a transportation fuel in LDVs. They also performed a “cradle-to-user” analysis for bio-acetone (which is co-produced with bio-butanol) to address the impacts of displacing petroleum-based acetone with the bio-acetone co-product. Merits and shortfalls of such process are discussed in this report.

By: M. Wu, M. Wang, J. Liu, and H. Huo (Argonne National Laboratory)

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