LEGISLATIVE AND TECHNICAL PERSPECTIVES FOR ADVANCED GROUND TRANSPORTATION SYSTEMS

This paper analyzes from legislative and technical perspectives 10 different scenarios for advanced ground transportation systems using natural gas to supplement oil. It is first shown that previous legislative efforts to promote the use of alternative fuels by incentives have failed because of a lack of infrastructure to store and distribute the fuels. The paper then compares the efficiencies of various fuel-vehicle options by means of a well-to-wheel fuel cycle that starts with the well at which the feedstock is extracted from the ground and ends with the power delivered to the wheels of the vehicle. The complete cycle includes feedstock production; feedstock transportation and storage; fuel production; fuel transportation, storage, and distribution; and finally the vehicle operations. Such an all-inclusive comparison is essential in order to accurately and fairly compare the efficiency of transportation fuel options. This approach indicates that at the present time hybrid-electric vehicles, particularly those using diesel engines, can achieve the highest efficiency among available technologies. Hydrogen spark ignition, all-electric battery-powered and methanol fuel cell vehicles rank lowest in well-to-wheel efficiency because of their poor fuel production efficiencies. The study also examines various options to reduce air pollution and concludes that any significant reduction requires repairing the worst 10% of polluting vehicles or removing them from the national transportation fleet.