You are here:
ENVIRONMENTAL LIFE CYCLE ASSESSMENT OF GASOLINE ALTERNATIVES: MTBE AND ETHANOL ADDITIVES
Citation:
Smith*, R L., J P. Abraham*, J C. Bare*, AND M A. Curran*. ENVIRONMENTAL LIFE CYCLE ASSESSMENT OF GASOLINE ALTERNATIVES: MTBE AND ETHANOL ADDITIVES. Presented at AIChE, San Francisco, CA, November 16 - 21, 2003.
Impact/Purpose:
To inform the public
Description:
Currently, the U.S. is considering options for additives to reformulated gasoline. To inform this debate the U.S. EPA's Office of Research and Development is conducting a screening life cycle assessment (LCA) of three gasoline alternatives. These alternatives include gasoline with MTBE, gasoline with ethanol, and gasoline with no oxygenate additive. The intention of this work is to determine relative scores of potential environmental impacts in several impact categories for the life cycles of these fuels. In this study the life cycles of gasolines with additives incorporate raw material extraction, production, transportation and use. For raw material extraction, the life cycles include crude oil and natural gas extraction and corn growing with fertilizer, pesticide, and herbicide applications. The production stage of the LCA includes petroleum refineries (including MTBE) and ethanol production from corn. In the transportation stage aspects of transporting crude oil, natural gas, MTBE, ethanol, and gasoline are considered. Finally, the use stage includes the burning and leaking losses of the gasoline alternatives in automobiles. To compare these gasoline alternatives a number of impact categories are modeled through the use of TRACI (Tool for the Reduction and Assessment of Chemical and Other Environmental Impacts, Bare, 2003). TRACI is a tool for studying impact assessments of human health and environmental categories. Those categories include ozone depletion, global warming, acidification, eutrophication, photochemical smog, human carcinogenic effects, human non-carcinogenic effects, human health criteria, ecotoxicity, and water use. The scores in these categories show where one alternative is environmentally better/worse and where specific parts of the life cycle for alternatives are environmentally better/worse. The results of this study (scheduled to be completed in draft form by July, 2003) could indicate that one alternative is obviously superior or inferior (although this is seldom the case in LCA). More likely, the results will indicate that certain life cycle stages or parts of stages will dominate the potential environmental impacts. These areas will be pointed out for further attention and the need for improvements in environmental performance.