A Life Cycle Framework to Assess and Enhance the Sustainability of Wireless Charging Electric Vehicle Systems

The large-scale penetration of electric vehicles (EVs) is an important strategy to mitigate environmental impacts as well as energy consumption of the transportation sector that is responsible for 28% of total U.S. energy use.... [ view full abstract ]

The large-scale penetration of electric vehicles (EVs) is an important strategy to mitigate environmental impacts as well as energy consumption of the transportation sector that is responsible for 28% of total U.S. energy use. However, there are critical challenges that compromise the promised sustainability performance of EVs, stemming from: 1) the limited accessibility of charging stations constraining the range of EVs that leads to range anxiety; and 2) the high upfront retail price of EVs limiting the economic performance mainly because of the expensive and heavy onboard battery. Wireless power transfer (WPT) for EVs, known as wireless charging technology, is an emerging charging method alternative to plug-in charging for EVs. Deploying wireless charging infrastructure at bus stops, traffic intersections, congestion areas as well as freeways enables convenient and widespread charging accessibility, and also enables significant downsizing (1/3 – 1/5 of original weight) of the heavy and expensive onboard EV battery because of multiples “opportunity charges” en route. Battery downsizing has significant implications for lightweighting the vehicle and improving fuel economy so as to reduce the life cycle impacts of EVs. However, large-scale deployment of wireless charging infrastructure poses critical sustainability trade-offs which have not been well characterized through sustainability assessments.

This research develops new integrated life cycle assessment and life cycle cost (LCA-LCC) models, and strategies based on life cycle optimization (LCO) to effectively evaluate the trade-offs, and guide development and deployment of wireless charging technologies. This research is built upon authors’ previous work about a comparative life cycle assessment of stationary wireless charging vs. plug-in charging by modeling a transit bus system in Ann Arbor as a case study. The study highlighted that the battery downsizing and lightweighting benefits can cancel out the additional energy, environmental, and economic burdens from wireless charging infrastructure deployment.

The presentation will not only highlight the state-of-the-art technology development, but also provide insights to critically examine the role of WPT technology in the trend of advancing vehicle electrification and improving the sustainability of electrified mobility. A parametric life cycle model framework is applied for the assessment of dynamic wireless charging technology (i.e., charging electric cars in-motion). It assesses the key influences of timing and location of wireless charge/discharge events on the life cycle performance of wireless charging EV systems. A multi-objective life cycle optimization framework is being established to enhance the economic and environmental performance of the dynamic wireless charging infrastructure deployment by deciding when (in which year) and where (at which segments of roadways) to roll out the infrastructure, in order to minimize the life cycle cost and GHG emissions. Several spatial and temporal factors will be taken into consideration, including traffic speed and volume, system efficiency improvement, market penetration scenarios and demand growth of wireless EVs, urban road vs. highway, and economy of scale in the future.

Future research will characterize the synergistic effect, benefits, and trade-offs of coupling wireless charging with autonomous vehicles by modeling a shared autonomous and wireless charging EV fleet in metropolitan areas.