FULL-FUEL-CYCLE MODELING FOR ALTERNATIVE TRANSPORTATION FUELS

Utilization of alternative fuels in the transportation sector has been identified as a potential method for mitigation of petroleum-based en ergy dependence and pollutant emissions from mobile sources. Tradition ally, vehicle tailpipe emissions have served as sole data when evaluat ing environmental impact. However, considerable differences in extract ion and processing requirements for alternative fuels makes evident th e need to consider the complete fuel production and use cycle for each fuel scenario. The work presented here provides a case study applied to the southeastern region of the United States for conventional gasol ine, reformulated gasoline, natural gas, and methanol vehicle fueling. Results of the study demonstrate the significance of the nonvehicle p rocesses, such as fuel refining, in terms of energy expenditure and em issions production Unique to this work is the application of the MOBIL ES mobile emissions model in the full-fuel-cycle analysis. Estimates o f direct and indirect greenhouse gas production are also presented and discussed using the full-cycle-analysis method.