Refining Estimates of Fuel-Cycle Greenhouse-Gas Emission Reductions Associated with California’s Clean Vehicle Rebate Project with Program Data and Other Case-Specific Inputs

Abstract

This work refines and updates estimates of the fuel-cycle greenhouse-gas (GHG) emission impacts of electric vehicles (EVs) rebated in California. Emissions are estimated using disaggregated data from the start of the rebate program through August 2018 (N = 269,902 participants) and factors that characterize fuel use and fuel life-cycle carbon intensity. GHG reductions are calculated for the first year of vehicle operation and subsequently scaled to reflect various operational timeframes. GHG reduction estimates over the first year of vehicle ownership total approximately 855 thousand metric tons of CO2-equivalent emissions, or 3.2 tons per vehicle. For nonfleet individuals, 54% of reductions are associated with “Rebate-Essential” participants who were most highly influenced by the rebate to purchase/lease. Comparing the estimated warranty-life benefit of 7.9 million tons of GHG reductions to USD 603 million in corresponding rebates results in USD 76 of state incentives per metric ton reduced over the first 100,000/150,000 miles of rebated vehicle use. Uncertainty in estimates presents opportunities for further refinement using additional participant-specific, time-variant, or otherwise detailed inputs. Nevertheless, the contributions of this work increased average first-year GHG reductions per vehicle by 35–45% compared to previous work, demonstrating that use of program-derived data can enhance the understanding of EV impacts.