Procedure for Recommissioning of H2 Bus Refueling Systems at the Karlsruhe Institute of Technology

On the initiative of and with financial support from the Ministry of the Environment of the State of Baden-Württemberg, Germany, the presidium of the Karlsruhe Institute of Technology (KIT) decided in fall 2009 to build a hydrogen (H₂) fueling station as one essential element of a filling station of the future. The KIT H₂ refueling station was designed to serve two H₂ fuel cell buses, replacing the conventional diesel buses of the KIT shuttle bus service. After completion of the fueling station and delivery of the two H₂ fuel cell buses, both of which were the 12 m City Bus Standard type from EvoBus GmbH (which has since become Daimler Buses GmbH, part of Daimler Truck), the KIT H₂ shuttle started operation in 2011. The buses had an operating license of 10 years for the hydrogen tank system, expiring in 2021. To enable the buses to continue to operate, KIT, TÜV SÜD (Technical Inspection Association South (Germany)), the bus contract workshop (S&G Automobil AG) and Pro-Science GmbH worked together to find a way to extend the operating license of the bus tank system. Neither regulations, standards nor technical recommendations were available for this process, which had never been done before in Europe to the knowledge of the authors. This paper describes the procedure finally agreed with the surveillance body and highlights the main points of the tests required for renewal of the license. After a two-month break, the successful recommissioning of the bus refueling systems allowed the system’s lifetime to be extended by five years.