L.R. Waterland, J. Pont, M.D. Jackson, M. Addy
A full fuel cycle assessment of alternative transportation fuels in California was performed. This well to wheel assessment determined the energy inputs, greenhouse gas (GHG) emissions, criteria pollutant emissions, air toxics emissions, and multimedia impacts from the production and use of a variety of conventional and alternative fuels that are considered options for on road vehicle and off road equipment applications in California. Results show that, depending on fuel pathway, alternative fuels like ethanol, natural gas, LPG, electricity and hydrogen, can provide significant reductions in well to wheels GHG emissions when used in light duty vehicles, though alternative fuel pathways result in criteria pollutant emissions comparable to gasoline pathways. For example, biofuel pathways can provide up to 75% GHG reductions compared to gasoline depending on the specific fuel production process. For heavy duty vehicles, many of the fuels provide a GHG benefit, but not as significant as that for light duty vehicles, and criteria pollutant emissions for alternative fuel pathways are generally either similar to or slightly below the diesel baseline. For example, electric heavy duty vehicles provide the most significant GHG benefit, at 55% reduction, followed by hydrogen fuel cell and CNG vehicles at 23% to 24% reduction.