Evaluating technology options to support the transition to zero-emission buses in California’s transit agencies
In February 2000, the California Air Resources Board adopted the Fleet Rule for Transit Agencies which includes a requirement that larger transit agencies begin to purchase buses with zero exhaust emissions (“zero-emission buses”). This zero-emission bus purchase requirement was originally scheduled to begin in 2008, but only after a demonstration phase in which participating transit agencies procured and successfully operated qualifying buses. This report covers two of the three technologies which, by regulation, qualify to meet the zero-emission bus requirements, namely hydrogen fuel cells and electric batteries. The third technology, catenary electric buses, is not covered in this report.
The original April 2012 edition of this report was prepared upon completion of the initial round of zero-emission bus demonstration projects and midway through a second demonstration. The intent of the second phase was to demonstrate zero-emissions buses on a larger scale with the hope of eliminating the operational and financial challenges experienced during the initial demonstration. After an initial round of demonstration projects, fuel cell buses were approximately 4.5 times as expensive to purchase, only 15 percent as reliable, and cost $4.60 per mile more to operate than a natural gas bus, which had become the standard technology in the South Coast Air Basin. The operational and financial challenges experienced during the initial demonstration prompted a delay in the purchase requirement schedule while the second advanced demonstration was implemented.
As a follow-up to the original edition of this report, the June 2014 edition has been prepared to incorporate the final results of the second round of advanced demonstration projects, which recently became available. In addition to evaluating the results, the June 2014 edition includes: updates to the technology and operational cost assumptions used in the model, revisions to the fuel pathway values, an assessment of the current state of fuel cell technology compared to recently released DOE/FTA cost and performance targets, and an analysis of additional hydrogen and electric fuel pathways.
