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• Evaluated pathways to reduce metal use & GHG emissions from US EV batteries (LIBs). • US will face metal supply constraints when transitioning to fully electric fleet. • Cumulative 2020–2050 battery production GHG emissions range from 1.3 to 1.6 gt CO 2 e. • Differences in use-phase due to LIB weight can surpass 20% of LIB production GHGs. • Aggressive PHEV penetration has GHG benefits with less critical material use. We evaluated the battery material demand and GHG emissions implications from high EV and very aggressive Plug-in Hybrid EV (PHEV) penetration rates for the U.S. light-duty vehicle fleet from 2020 to 2050. If the U.S. relies primarily on EV deployment to decarbonize passenger transport, there are potentially significant supply constraints over the next decade, particularly for cobalt, lithium, and nickel. Very aggressive PHEV deployment has the potential to reduce GHGs and with ∼80% lower demand on critical metals. Recycling can play a major role reducing metal demand in the long-term but until 2035, shifting to an iron-based battery cathode reduces critical metal use by more than recycling would but with higher charging emissions due to increased weight. Increasing recycling, shifting battery chemistry, and adopting low-carbon electricity for battery production can avoid 250 million tonnes CO 2 e in cumulative GHG emissions from 2020 to 2050 (equivalent to 15% of U.S. transportation sector's 2020 GHG emissions). [ABSTRACT FROM AUTHOR]

The literature analyzes changes in vehicle attributes that can improve fuel economy to meet Corporate Average Fuel Economy (CAFE) standards. However, these analyses exclude either vehicle price, size, acceleration or technology advancement. A more comprehensive examination of the trade-offs among these attributes is needed, this case study focuses on technically feasible modifications to a reference 2012 vehicle to meet the 2025 fuel economy target. Scenarios developed to examine uncertainty in technology advancement indicate that expected technology cost reductions over time will be insufficient to offset the costs of additional fuel efficiency technologies that could be used to meet the 2025 fuel economy target while maintaining other vehicle attributes. The mid-price scenario results show the targeted 66% increase in fuel economy from 2012 to 2025 can be achieved with (i) a 10% ($2070) vehicle price increase (lightweight hybrid electric vehicle), (ii) a 31% (2.9 second) increase in the 0–97 km/h (60 mph) acceleration time (smaller engine), or (iii) a 17% (700 L) decrease in interior volume (smaller body) while maintaining other vehicle attributes. These results are consistent with those obtained using methods that generalize the US light-duty vehicle fleet, but are not a forecast of future vehicle attributes because combinations of less perceptible changes to vehicle price, acceleration and size would also be feasible. This study shows there are numerous ways that 2025 fuel economy targets can be met; therefore, the trade-offs quantified provide important insights on the implications of future CAFE standards. [ABSTRACT FROM AUTHOR]

Automated vehicles can facilitate vehicle sharing within and between households, thus decreasing ownership rates, albeit increasing miles travelled. While electrification can achieve deep reductions in transportation-related greenhouse gas emissions, shared automated electric vehicles will have different charging needs considering their higher mileage. In this study, travel survey data collected in Toronto is used to optimize the charging needs of shared automated electric vehicles, with the objective of reducing greenhouse gas emissions from electricity generation by choosing charging times that are associated with lower marginal emission factors. Optimized charging schedules reduce greenhouse gas emissions by at least 50% relative to vehicles charging once they return home. Life cycle assessment of multiple sharing scenarios indicates that higher levels of sharing increase emissions. Indeed, empty mileage associated with vehicle relocation and higher deterioration lead to a higher fleet turnover. With vehicle sharing, there is a risk of increasing mileage and vehicle production emissions. [ABSTRACT FROM AUTHOR]

Our study evaluates life cycle energy use and GHG emissions of lignocellulosic ethanol and bioelectricity use in U.S. light-duty vehicles. The well-to-pump, pump-to-wheel, and vehicle cycle stages are modeled. All ethanol (E85) and bioelectricity pathways have similar life cycle fossil energy use ( ~100 MJ/100 vehicle kilometers traveled (VKT)) and net GHG emissions (~5 kg CO2eq./100 VKT), considerably lower (65-85%) than those of reference gasoline and U.S. grid-electricity pathways. E85 use in a hybrid vehicle and bioelectricity use in a fully electric vehicle also have similar life cycle biomass and total energy use ( ~350 and ~450 MJ/100 VKT, respectively); differences in well-to-pump and pump-to-wheel efficiencies can largely offset each other. Our energy use and net GHG emissions results contrast with findings in literature, which report better performance on these metrics for bioelectricity compared to ethanol. The primary source of differences in the studies is related to our development of pathways with comparable vehicle characteristics. Ethanol or vehicle electrification can reduce petroleum use, while bioelectricity may displace nonpetroleum energy sources. Regional characteristics may create conditions under which either ethanol or bioelectricity may be the superior option; however, neither has a clear advantage in terms of GHG emissions or energy use. [ABSTRACT FROM AUTHOR]