With four sets of public results having been presented previously at 6-month intervals, this paper comes after over almost three years of data have been received, and just after some second-generation fuel cell stacks and vehicles began operation and some early vehicles were retired.  With an average accumulated hours of real-world operation ranging from 200-600 hours, and the first stacks surpassing 1,000 hours, there is now a higher level of confidence in the trends and projections relating to the durability and voltage degradation of the first-generation fuel cell stacks.  

 Public results for this project are in the form of composite data products, which aggregate individual performance into a range that protects the intellectual property and the identity of each company, while still publishing overall status and progress.  In addition to generating composite data products, NREL is performing additional analyses to provide detailed recommendations back to the R&D program.  This includes a much deeper exploration of the factors affecting fuel cell degradation with each team’s data individually, with some overall industry trends identified.  Some examples of the factors examined include vehicle duty cycle, number of fuel cell start cycles, time at idle, time between trips, and ambient temperature.  Future project activities and analyses will also be discussed.