A full fuel-cycle analysis of energy and emissions impacts of transportation fuels produced from natural gas

Because of its abundance and because it offers significant energy and evironmental advantages, natural gas has been promoted for use in motor vehicles. A number of transportation fuels are produced from natural gas; each is distinct in terms of upstream production activities and vehicle usage. In this study, the authors avaluate eight fuels produced from natural gas - compressed natural gas, liquefied petroleum gas, methanol, hydrogen, dimethyl ether, Fischer-Tropsch diesel, and electricity--for use in five types of motor vehicles--spark-ignition vehicles, compression-ignition vehicles, hybrid electric vehicles, battery-powered electric vehicles, and fuel-cell vehicles. Because of great uncertainties associated with advances both in fuel production and vehicle technologies, they evaluate near-term and long-term fuels and vehicle technologies separately. Furthermore, for long-term options, they establish both an incremental technology scenario and a leap-forward technology scenario to address potential technology improvements. The study reveals that, in general, the use of natural gas-based fuels reduces energy use and emissions relative to use of petroleum-based gasoline and diesel fuel, although different natural gas-based fuels in different vehicle technologies can have significantly different energy and emissions impacts