Another Way To Go?: Some Implications of Light-duty Diesel Strategy

Conventional wisdom suggests that a large-scale shift from gasoline to diesel light-duty highway vehicles would have an impact on energy consumption, emissions, and infrastructure. Under a relatively modest scenario, based on French experience since 1970, a dieselization strategy could have displaced slightly more than half a quad of petroleum (3.7 percent of the energy consumed by light-duty vehicles) in 1992, while reducing carbon monoxide (CO), hydrocarbon (HC), and nitrogen oxide (NO_x) emissions by 6.3, 0.8, and 0.09 million tonnes, and increasing sulfur oxides (SO_x) and particulates (PM-10) by 0.03 and 0.2 million tonnes, respectively. As a percentage of pollutants attributable to light-duty vehicles, these values represent decreases of 11 percent, 10 percent, and 2 percent for CO, HC, and NO_x and increases of SO_x and PM-10 of 36 percent and 39 percent, respectively. The projected oil displacement and emissions impacts would have been achieved by using a diesel technology that is significantly less efficient than what is currently available and what may become available as a result of current research. Energy consumed in refining would also have been marginally reduced, although additional processing could have been required to increase the fraction of distillate and decrease that of gasoline. Finally, a shift to diesel could have broad implications on U.S. and world oil markets, modifying crude oil supply-demand balances and requiring a different mix of unit operations in domestic refineries that, in turn, could change the capital investment path of the industry, which is currently geared to maximizing gasoline production.