Hydrogen in the mobility sector offers great opportunities to achieve the decarbonization goals and to reduce the local emissions. In particular, public transportation, with its high daily mileage and its services both within cities and across regions, offers the best conditions. In the state funded research project „H2FLEX“ the interoperatability of hydrogen across different sectors like heat, electricity and mobility is focussed. The universities of applied sciences in Esslingen, Reutlingen and Ulm jointly perform the research within various work packages. One of these workpackages deals with modelling, simulation, optimization and evaluation of the hydrogen hub „Hy.Waiblingen“ which produces green hydrogen with PEM electrolysis and is further equipped with low, medium and high pressure storages and a hydrogen fueling station with dispensers for passenger cars and heavy duty transportation. Furthermore the hydrogen hub can refill up to two hydrogen trailers and also be supplied with an external hydrogen trailer for additional fueling capacity. Main focus is the supply of fuel-cell electric busses of dedicated bus lines of the local county. The study goal is to model the existing hydrogen hub and simulate its behaviour for different demand scenarios. To ensure the model accuracy, the expected hub behaviour will be validated with real hub measurement data and apapted accordingly. The simulation models answer various questions like: - Ideal hub operation conditions for different fueling scenarios for fueling frequencies, time windows and amount of busses, - Hub performance limitations under different circumstances - Hub resilience in case of downtime of hub sub systems - Possible Multi-Megawatt scaling and hub-extensions for higher hydrogen supply demands, - Waste-heat discovery potential to serve existing and new district heating networks.