One fuel cell electric bus (FCEB) operating in the United States has surpassed 29,000 hours of drive time and nine buses have exceeded 20,000 hours without major repairs or replacement of the fuel cell stack, according to the US Department of Energy (DOE). This is comparable to the life expectancy of a diesel engine in a transit bus.
Diesel buses have an engine that is sometimes rebuilt halfway through its usable life at 6 years/250,000 miles on average. The National Renewable Energy Laboratory (NREL) has collected data on fuel cell buses for more than 8 years.
In December 2018, NREL researchers Leslie Eudy and Matthew Post summarized the progress of fuel cell electric bus (FCEB) development in the United States and discussed the achievements and challenges of introducing fuel cell propulsion in transit in a technical report published by the lab.
The report provides a summary of results from evaluations performed by NREL. The data from these early FCEB deployments funded by the US Department of Transportation, state agencies, and the private sector help to guide future early-stage research and development supported by DOE’s Fuel Cell Technologies Office.
Graph extracted from L. Eudy, National Renewable Energy Laboratory, funded by DOT and DOE-FCTO. Several transit agencies are deploying fuel cell buses. Not all buses have been in service for sufficient time to determine if they can meet durability targets so only those with adequate time on the road are shown.
NREL considers these FCEB designs to be around technology readiness level (TRL) 7 to 8, that is, full-scale validation in a relevant environment. At this point in development, capital and operating costs for FCEBs are still higher than those of conventional diesel and compressed natural gas technology. This is to be expected considering both diesel and compressed natural gas are mature technologies (TRL 9) and FCEBs are still in the early deployment stage.—Eudy and Post (2018)
The US Department of Energy’s (DOE’s) Fuel Cell Technologies Office (FCTO) within the Office of Energy Efficiency and Renewable Energy, and the US Department of Transportation (DOT) Federal Transit Administration funded this work.
L. Eudy and M. Post (2018) Fuel Cell Buses in U.S. Transit Fleets: Current Status 2018 NREL/TP-5400-72208