title: Comparative Assessment of Models and Methods To Calculate Grid Electricity Emissions.
abstract: Due to the complexity of power systems, tracking emissions attributable to a specific electrical load is a daunting challenge but essential for many environmental impact studies. Currently, no consensus exists on appropriate methods for quantifying emissions from particular electricity loads. This paper reviews a wide range of the existing methods, detailing their functionality, tractability, and appropriate use. We identified and reviewed 32 methods and models and classified them into two distinct categories: empirical data and relationship models and power system optimization models. To illustrate the impact of method selection, we calculate the CO2 combustion emissions factors associated with electric-vehicle charging using 10 methods at nine charging station locations around the United States. Across the methods, we found an up to 68% difference from the mean CO2 emissions factor for a given charging site among both marginal and average emissions factors and up to a 63% difference from the average across average emissions factors. Our results underscore the importance of method selection and the need for a consensus on approaches appropriate for particular loads and research questions being addressed in order to achieve results that are more consistent across studies and allow for soundly supported policy decisions. The paper addresses this issue by offering a set of recommendations for determining an appropriate model type on the basis of the load characteristics and study objectives.
authors: Center for Sustainable Systems, School of Natural Resources & Environment, University of Michigan , 440 Church Street, Ann Arbor, Michigan 48109, United States.|Department of Mechanical Engineering, University of Michigan , 2350 Hayward Street, Ann Arbor, Michigan 48109, United States.
authors: Nicole A
authors: NA
authors: Ryan
authors: Center for Sustainable Systems, School of Natural Resources & Environment, University of Michigan , 440 Church Street, Ann Arbor, Michigan 48109, United States.
authors: Jeremiah X
authors: JX
authors: Johnson
authors: Center for Sustainable Systems, School of Natural Resources & Environment, University of Michigan , 440 Church Street, Ann Arbor, Michigan 48109, United States.|Department of Civil and Environmental Engineering, University of Michigan , 2350 Hayward Street, Ann Arbor, Michigan 48109, United States.
authors: Gregory A
authors: GA
authors: Keoleian
mesh_terms: D000393:Air Pollutants; D004560:Electricity; D008962:Models, Theoretical; D014481:United States; D001335:Vehicle Emissions
chemical_list: D000393:Air Pollutants; D001335:Vehicle Emissions