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Estimating Impacts Across the Life Cycle of Corn Ethanol and Gasoline
Citation:
Hawkins, T., W. Ingwersen, D. Sengupta, X. Xue, AND R. Smith. Estimating Impacts Across the Life Cycle of Corn Ethanol and Gasoline. Presented at ISSST 2012, Boston, MA, May 16 - 18, 2012.
Impact/Purpose:
This presentation presents preliminary results from the ACE 153 research task on a life cycle assessment of gasoline and ethanol blends.
Description:
Direct emissions from transportation are responsible for roughly one-quarter of the total US greenhouse gas emissions (EPA 2011). U.S. oil use is also associated with a relatively high degree of externality cost (Michalek, Chester et al. 2011). Under the Energy Independence and Security Act of 2007, a substantial proportion of gasoline and diesel will be replaced by biofuel alternatives by 2022. To meet this increased demand, a number of new facilities and technologies have and continue to come online. In addition to biofuels, the transportation sector is also undergoing a trend toward hybrid and electric vehicles which offer the potential for increased energy efficiency and reduction of tailpipe emissions. These changes, primarily focused on addressing energy security and greenhouse gas concerns, are occurring within the context of continued efforts to reduce toxic impacts on human health and ecosystems. From both an industry and regulatory perspective, managing toxicity together with other outcomes of interest associated with this rapid evolution of the transportation sector requires models and data for identifying and prioritizing hot spots within the life cycles of existing and prospective technologies. Here we present results of a model addressing the question, what are tradeoffs in environmental impacts associated with gasoline and ethanol-based alternatives? Preliminary results focused on identifying and prioritizing life cycle hotspots for gasoline, low-level and high level ethanol-blend (E10 and E85) fuels are presented. All life cycle stages from oil extraction/corn cultivation to final vehicle use are modeled. Impacts are characterized using the TRACI2 methodology along with selected resource use methods from ReCIPE. Releases for a number of supply chain processes including ethanol production, refining, fertilizer production, and pesticide production are estimated using the US National Emissions Inventory (EPA 2011) and Toxics Release Inventory (E