This paper for the January 2022 reschedule of the International Energy Program Evaluation Conference (ultimately rescheduled again and held November 2022) builds on prior work to create a more detailed, more current, and two-state picture of fuel-cycle greenhouse-gas (GHG) emission impacts and cost-effectiveness of electric vehicle rebate programs in California and Massachusetts. Emissions are estimated using disaggregated data from vehicles purchased/leased in 2019 (N= 65,018) and factors that characterize fuel use and fuel carbon intensity.

Depending on the technology of the vehicle rebated, reductions estimates over the first year of ownership average 2.0–3.1 metric tons of CO2-equivalent emissions per vehicle in Massachusetts and 2.2–3.8 tons in California. Comparing rebate costs to rebated-vehicle emissions benefits over operational lifetimes of 100,00 to 150,000 miles produces CO2-equivalent abatement costs ranging from $53 per metric ton for plug-in hybrid EVs to $300 per ton for fuel-cell EVs. Discussion includes comparisons to previous research and the challenge of developing comparable results across states.

Approximately 55% of California-rebated reductions and 40% of Massachusetts-rebated reductions are associated with “Rebate-Essential” participants who were most highly influenced by the rebate to purchase/lease. Approximately 72% of reductions from recipients of California’s Increased Rebate for Low-/Moderate-Income households were Rebate Essential.

Uncertainty in estimates presents opportunities for further refinement using additional participant-specific, time-variant, or otherwise detailed inputs. Nevertheless, this work substantially changes prior GHG estimates, demonstrating that the use of program-derived data can enhance the understanding of EV impacts.