The role of natural gas as a vehicle transportation fuel

Abstract

This thesis analyzes pathways to directly use natural gas, as compressed natural gas (CNG) or liquefied natural gas (LNG), in the transportation sector. The thesis focuses on identifying opportunities to reduce market barriers in order to make the US natural gas vehicle market more efficient. We also identify vehicle market segments where NGV technology is mature and does not require sustained public subsidy to economically compete with comparable gasoline or diesel vehicles. This thesis finds that natural gas can play a useful but modest role as a vehicle fuel in the US, predominantly as CNG in high-mileage, light-duty fleet vehicles and in heavy-duty, short-haul fleet vehicles. For light-duty applications, there is a need to address an existing market barrier in the US by reducing the incremental cost and improving the vehicle performance of CNG vehicles to levels found in Europe. This incremental cost reduction is critical to foster market penetration in high-mileage fleet vehicles and to create a potential opportunity for market penetration beyond high-mileage fleet vehicles to average-mileage individual drivers. Increased use of CNG in light duty vehicles would displace petroleum, reduce greenhouse gas emissions in the transportation sector, and hedge consumers from volatile world oil prices (if CNG is used in a bi-fuel - gasoline and CNG- vehicle). In the heavy-duty, short-haul sector, CNG provides an additional benefit of reduced nitrogen oxide emissions compared to diesel trucks. With respect to long-haul LNG trucks, this thesis finds that while there is a large potential market for natural gas in the long-haul truck market, the present prospects for the use of LNGpowered long haul trucks appears quite limited. This is due to high incremental costs, unresolved operational issues, fueling infrastructure requirements, and reluctance of the trucking industry.