Decarbonization potential of electrifying 50% of U.S. light-duty vehicle sales by 2030.

The U.S. federal government has established goals of electrifying 50% of new light-duty vehicle sales by 2030 and reducing economy-wide greenhouse gas emissions 50-52% by 2030, from 2005 levels. Here we evaluate the vehicle electrification goal in the context of the economy-wide emissions goal. We use a vehicle fleet model and a life cycle emissions model to project vehicle sales, stock, and emissions. To account for state-level variability in electric vehicle adoption and electric grid emissions factors, we apply the models to each state. By 2030, greenhouse gas emissions are reduced by approximately 25% (from 2005) for the light-duty vehicle fleet, primarily due to fleet turnover of conventional vehicles. By 2035, emissions reductions approach 45% if both vehicle electrification and grid decarbonization goals (100% by 2035) are met. To meet climate goals, the transition to electric vehicles must be accompanied by an accelerated decarbonization of the electric grid and other actions.

Life Cycle Greenhouse Gas Emissions of the USPS Next-Generation Delivery Vehicle Fleet.

The United States Postal Service (USPS) plans to purchase 165,000 next-generation delivery vehicles (NGDVs) between 2023 and 2032. The USPS submitted an environmental impact statement (EIS) for two NGDV procurement scenarios: (1) 90% internal combustion engine vehicles (ICEVs) and 10% battery electric vehicles (BEVs) ("ICEV scenario") and (2) 100% BEVs ("BEV scenario"). To correct several significant deficiencies in the EIS, we conduct a cradle-to-grave life cycle greenhouse gas (GHG) assessment of these two scenarios. Our analysis improves upon the USPS's EIS by including vehicle production and end-of-life emissions, future grid decarbonization, and more accurate vehicle operating emissions. In our base case, we find that the ICEV and BEV scenarios would result in 15% greater and 8% fewer GHG emissions, respectively, than the USPS estimate. Favorable vehicle and grid development would result in 63% lower BEV scenario emissions than the USPS estimate. Consequently, we calculate a cumulative lifetime emission reduction of 57-82% (14.7-21.4 Mt CO2e) from procuring 100% BEVs instead of 10% BEVs, compared to the USPS's estimate of 10.3 Mt. Given the long NGDV lifetimes, committing to the ICEV scenario squanders an ideal use case for BEVs, jeopardizes meeting our climate goals, and forgoes potential climate and environmental justice co-benefits.

Charging Strategies to Minimize Greenhouse Gas Emissions of Electrified Delivery Vehicles.

Electrification of delivery fleets has emerged as an important opportunity to reduce the transportation sector's environmental impact, including reducing greenhouse gas (GHG) emissions. When, where, and how vehicles are charged, however, impact the reduction potential. Not only does the carbon intensity of the grid vary across time and space, but charging decisions also influence battery degradation rates, resulting in more or less frequent battery replacement. Here, we propose a model that accounts for the spatial and temporal differences in charging emissions using marginal emission factors and degradation-induced differences in production emissions using a semi-empirical degradation model. We analyze four different charging strategies and demonstrate that a baseline charging scenario, in which a vehicle is fully charged immediately upon returning to a central depot, results in the highest emissions and employing alternative charging methods can reduce emissions by 8-37%. We show that when, where, and how batteries are charged also impact the total cost of ownership. Although the lowest cost and the lowest emitting charging strategies often align, the lowest cost deployment location for electric delivery vehicles may not be in the same location that maximizes environmental benefits.