| Abstract |
Pollution and energy analyses of different idling reduction (IR) technologies have been limited to localized vehicle emissions and neglected upstream energy use and regional emissions. In light of increasing regulation and government incentives for IR, we analyzed the full-fuel-cycle effects of contemporary approaches. Our analysis incorporates direct impacts at the truck and upstream energy use and emissions estimates from the GREET model with published climate and vehicle operation data. We compared emissions, energy use, and proximity to urban populations for nine alternatives, including idling, electrified parking spaces, auxiliary power units, and several combinations of these. We compared effects for the United States and seven states: California, Florida, Illinois, New York, Texas, Virginia, and West Virginia. U.S.-average emissions impacts from all onboard IR options were found to be lower than those from a 2007-compliant idling truck. Total particulate emissions from electrified parking spaces were found to be greater than those from a 2007 truck, but such emissions generally occurred in areas with low population density. The lowest energy use, CO2 emissions, and NOx emissions are seen with a direct-fired heater combined with electrified parking spaces for cooling, and the lowest PM10 emissions were found with a direct-fired heater combined with an onboard device for cooling. As expected, state-to-state variations in climate and grid fuel mix influence the full fuel-cycle impacts from IR technologies, and the most effective choice for one location may be less effective elsewhere. The many assumptions have a significant effect on the results. However, idling duration, which has considerable seasonal and spatial variation, affects the energy and emissions for any technology in direct proportion to the number of hours, but not the relative technology benefits, as long as the portion of heating and cooling time is held constant. Changes in the fraction of time spent heating or cooling do change the relative impacts. |
