Optimal system design and ideal application of flywheel energy storage systems for vehicles

Even though the r&d activities in the field of energy storage are currently being pushed all over the globe, the results are still far from satisfactory. This paper describes how the benefits of flywheel energy storage systems (FESS) can be exploited even though some properties still need to be improved significantly in the near future. Within a research project at the Graz University of Technology an FESS for application in vehicles serving urban public transportation (UPT) was investigated. The systematic design process and the problems of the proposed topology are discussed. Finally, solutions are suggested, which allow the maximum exploitation of the properties of kinetic energy storage. These recommended solutions do not only affect the flywheel design itself, but also its mode of application. This means that a holistic approach was chosen, which takes into account the whole super-system of the flywheel hybrid vehicle.