When it comes to reducing carbon emissions from transportation in the US, public transit is an important piece of the puzzle. To many, that means more buses, but buses emit carbon dioxide, too. What types of buses are most effective at reducing emissions?
This study is the culmination of a graduate course on Life-cycle Assessment (LCA). My teammates (Siena and Elliott) and I analyzed and compared the global warming potential (GWP) of both battery electric buses (BEBs) and fuel cell electric buses (FCEBs) in the East Bay Area.
Full Report
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Abstract
The transportation sector accounts for 28% of annual greenhouse gas emissions, and thus adoption of zero-emissions vehicles is a crucial component of any decarbonization strategy. While battery electric personal vehicles (BEVs) have seen significant commercial interest, less attention has been paid to similar applications of zero emission technologies to public transportation, most notably buses. This study aims to compare two competing technologies that have emerged as promising solutions for zero emission buses – battery electric (BEB) and hydrogen fuel cell (FCEB), with diesel as a baseline. We specifically analyze the life cycle emissions of these 3 technologies serving AC Transit bus routes within Alameda and Contra Costa Counties, and determine the viability of zero emission technologies as a replacement for diesel powered buses. We found that BEBs generally had the lowest life cycle emissions, but found that emissions of FCEBs depended heavily on the source of hydrogen. Hydrogen obtained from natural gas is associated with significantly more emissions than hydrogen obtained from electrolysis. These findings highlight the importance of comprehensive systemic decarbonization, including zero-emission electricity generation and green hydrogen technology, in order to achieve decarbonization of the transportation sector.