SEAS Events

Title: 

Decarbonizing Road Transportation: Energy, Emissions, Cost, and Policy Drivers for Battery Electric and Hydrogen Fuel Cell Vehicles

Abstract:

Decarbonizing the road transportation sector, which makes up 23% of U.S. greenhouse gas (GHG) emissions, is critical to meeting climate goals. Deploying battery electric and hydrogen fuel cell vehicles will play a primary role in reducing GHG emissions. But the technologies, policies, and timelines will vary across light-, medium-, and heavy-duty vehicles and across freight and passenger transport due to the different performance requirements of each purpose and mode.
This dissertation characterizes decarbonization pathways across modes, looking at the key drivers, including environmental performance, economic performance, and policy support. It addresses research questions specific to each mode, using life cycle assessment, techno-economic analysis, and policy analysis techniques. Ultimately, this dissertation aims to encourage and accelerate the decarbonization of road transportation by investigating the key technologies and policies driving the transition.

 The first half of the dissertation (Chapters 2-4) focuses on the electrification of light duty vehicles. First, I assess the U.S. goal of reaching 50% electric vehicle (EV) sales in the light-duty sector by 2030. Even if sales goals are met, emissions reductions in this sector fall short of the U.S. economy wide emissions target of a 50-52% reduction from 2005 levels by 2030 due to long vehicle lifetimes and slow fleet turnover.

Next, I investigate one of the main barriers to widespread EV adoption – cost. I compare the total cost of ownership (TCO) of gasoline and electric vehicles across the U.S. to provide insight into consumer decision making and to highlight opportunities to lower TCO and accelerate EV adoption. New EVs are currently cost competitive only for small or low-range models; however, in the used vehicle market light-duty EVs of all sizes are less costly than conventional alternatives.
 

Then, I discuss vehicle scrappage policies, which have the potential to hasten decarbonization by accelerating the turnover of the vehicle fleet. I review the successes and shortcomings of historic and contemporary scrappage programs and develop recommendations for future vehicle scrappage policies.

The second half of this dissertation (Chapters 5-6) focuses on the medium- and heavy-duty vehicle sector. While EVs are leading the way for light duty applications, the technological solutions for larger and heavier vehicles are less clear. First, I assess the use of green hydrogen for transportation, focusing on the energy efficiency and intensity of different hydrogen pathways. Hydrogen fuel cell vehicles use 3-4 times more renewable electricity than EVs and should be strategically deployed only in situations where electrification is not viable.
 

Lastly, I conduct a life cycle assessment of the GHG emissions of battery electric and hydrogen fuel cell medium- and heavy-duty vehicles, using a parametric model to assess which powertrain is environmentally preferable across a range of sizes, cargo weights, and driving patterns. Both alternative powertrains can achieve significant GHG reductions compared to diesel vehicles; however, fuel cell vehicles have higher renewable electricity demands and have hydrogen leakage throughout the supply chain.
 

Collectively, these studies provide a view towards the future of road transportation and the technology and policy tools needed to decarbonize the sector. Decarbonization requires ambitious goals with clear emissions reduction pathways, deployment of new technologies and infrastructure, and increased policy support to align economic and environmental drivers that will accelerate the transition. Implementing these strategies rapidly, efficiently, and justly gives the road transportation sector an opportunity to meet emissions goals and mitigate climate change.

Zoom Link: https://umich.zoom.us/j/98724984093     Password: Transport