Abstract
The higher capital and operating expenses of alternative fuel buses, such as battery-electric and hydrogen fuel cell buses, are a significant obstacle to their widespread deployment. Retrofitting existing diesel buses with electric batteries has been identified as a promising approach to reduce capital costs compared to new battery-electric buses. This concept is extended in this study to hydrogen fuel cell technology through the retrofitting of diesel buses with hydrogen fuel cells. Life cycle thinking and multicriteria decision-making are employed to identify and rank the cradle-to-grave environmental and economic implications of retrofitted and new hydrogen fuel cell buses across 10 Canadian provinces. Renewable hydrogen fuel production from locally available resources such as water and municipal solid waste is analyzed. A sensitivity analysis is performed to understand how fuel prices, fuel consumption of buses, and capital expenses affect the cost savings achieved via retrofitting, and to identify the economic and environmental implications of retrofitting diesel buses of different ages with hydrogen fuel cells. The results demonstrate considerable reductions in cradle-to-grave environmental impacts from both hydrogen fuel cell bus types, albeit at higher costs than diesel buses. Nevertheless, the cost per passenger-kilometer of bus operation can be reduced by up to 24% through retrofitting under varying conditions compared to new hydrogen fuel cell buses. Multicriteria decision-making under different stakeholder-priority scenarios shows that hydrogen fuel cell buses perform better overall than diesel buses, despite their higher costs.