For transit agencies looking to implement Zero Emission Vehicles (ZEV), Fuel Cell Electric Buses (FCEBs) represent an opportunity because of the similar range and refueling times compared to conventional buses, but with improved fuel economy. To assure an environmentally sensitive hydrogen infrastructure that can respond to the wide range of needs and limitations of transit agencies, a systematic evaluation of options is essential. This paper illustrates the systematic evaluation of different hydrogen infrastructure scenarios for a transit agency. The Orange County Transportation Authority (OCTA) in California was selected for the study.
Three different hydrogen infrastructure configurations are evaluated and compared to the existing paradigm of compressed natural gas buses and diesel buses. One additional scenario is analyzed in order to compare feasibility and environmental benefits of FCEBs with Plug-in Electric Buses. Each scenario represents (1) a specific mix and percentage of contribution from the various hydrogen generation technologies (e.g., on-site electrolysis, central SMR, and on-site SMR), (2) defined paths to obtain the corresponding feedstock for each generation process (e.g., biogas, natural gas, renewable energies), (3) detailed hydrogen distribution system (e.g., mix of gaseous/liquid truck delivery), and (4) the spatial allocation of the generation location and fueling locations (e.g., on-site / off-site refueling station) while also accounting for constraints specific to the OCTA bases.
This systematic evaluation provides Well-to-Wheel (WTW) impacts of energy and water consumption, greenhouse gases and criteria pollutant emissions of the processes and infrastructure required to deploy FCEBs and Plug-in Electric Buses at OCTA. In addition, this evaluation includes a detailed analysis of the space requirements and operations modifications that may be necessary, but yet feasible, for the placement of such infrastructure.