23 January 2019 -- One fuel cell bus 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. 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 has collected data on fuel cell buses for more than 8 years. The U.S. Department of Energy's (DOE's) Fuel Cell Technologies Office (FCTO) within the Office of Energy Efficiency and Renewable Energy, and the U.S. Department of Transportation (DOT) Federal Transit Administration funded this work.