Evaluating the life cycle greenhouse gas emissions from a lightweight plug-in hybrid electric vehicle in a regional context

Abstract

Life cycle assessment provides a comprehensive framework to evaluate the total greenhouse gas (GHG) emissions from electrified vehicles (EVs) and their potential for GHG reduction as they gain market share. The magnitude of EVs¿ contribution will depend on the specific combinations of fueling strategies and the other vehicle technologies adopted. For instance, the GHG emissions from plug-in electric vehicles (PHEVs) could increase life cycle emissions if the vehicle is driven in a region with a high carbon grid. Also, vehicle lightweighting with lighter, high strength materials decreases use phase emissions but can increase emissions throughout the material production process. This research develops a method to evaluate life cycle emissions from a lightweight PHEV for use in diverse electric fueling regions. A life cycle model is constructed using: 1) Autonomie, a vehicle simulation software, 2) GREET, a vehicle and fuel cycle model, and 3) eGrid, a database with regional information about the US electric power sector. The life cycle analysis demonstrates the importance of considering vehicle production emissions when using energy intensive materials to reduce mass from a vehicle, since life cycle GHGs for the 10% lightweight carbon fiber vehicle are higher than the baseline steel vehicle. However, as a higher percentage of steel is replaced with carbon fiber, total life cycle GHGs decrease. Regional impacts of the electric grid are shown to be significant, with the potential to decrease life cycle emissions by more than four times the reductions possible with the best-case lightweight scenario.