Downsizing fuel cell capacity in a hybrid hydrogen vehicle by regenerative energy capture with super capacitor

As phase one of the CHIC (Clean hydrogen in European cities) project, eight Fuel Cell (FC) hybrid buses on route RV1 have been put in service in central London. One of the next steps is to assess and determine the viability of switching from conventional diesel-technology to fuel cell technology on other bus routes in London. This paper reports on a study where a laboratory sized FC hybrid system modelled on the London hydrogen bus (RV1) is used to explore potential opportunities. Specifically, this paper examines the performance and optimization of a FC hybrid propulsion solution having a smaller FC and various energy storage arrangements. The proposed design is a series hybrid system for the urban driving environment, with focus on transit buses. A Proton Exchange Membrane Fuel Cell (PEMFC) has been selected with a Super Capacitor (SC) as the energy storage technology. The hybrid propulsion system has also been simulated in PSCAD and the model validated using the laboratory sized system. Of particular focus is the control strategy of the hybrid propulsion system to optimise power delivery efficiency during operation and optimise hydrogen consumption. The paper concludes by examining how FC technology can be applied to transit buses with the model validated by experiment and evaluation of the viability of adapting the technology technically. This is a project that is being progressed and this paper will focus on simulation part of the project.