To develop a prototype and then test it right away under everyday conditions of use is not an easy undertaking, and setbacks are practically preprogrammed. The hydrogen powered street cleaning vehicle, which took about 18 months to develop and began trials in Basel in 2009, is no exception. "It became clear relatively quickly that the fuel cell system, which had been developed as a one-of specially for the project, was not yet ready for use in a real-life setting," explains project leader Christian Bach, head of Empa's Internal Combustion Engines Laboratory. "On top of that, the various safety systems kept interfering with each other and bringing everything to a halt."
But because the vehicle achieved its targets both in terms of energy consumption and performance, the project team – which, in addition to researchers from Empa and the Paul Scherrer Institute (PSI), also included the vehicle manufacturer Bucher Schoerling, the electric drive specialist Brusa, the hydrogen manufacturer Messer Schweiz, and the city of Basel Environment and Energy Department as well as the city’s cleaning services – decided to replace the fuel cell system initially used with another more mature product, and also to implement a single centralized safety module. The "Fuel Cell System Mk 2" has now been in operation since the summer of last year and has proven to be far more robust: only once has it been necessary to take the vehicle out of service, because of a defective water pump.
But one problem rarely comes alone and sure enough the voltage converter between the fuel cell system and the battery died, then the sensing system for the electric motor drive as well as two cooling water pumps had to be replaced shortly after the vehicle was initially repaired. All these components were, it goes without saying, tailor-made for the vehicle and therefore had appropriately long delivery times. Despite these setbacks, however, for the past three months the vehicle has been running so reliably that the city cleaning services are able to use it on an everyday basis as they would a “normal” vehicle.