Trolleybus systems can be a sustainable replacement for regular diesel powered busses. By implementing such a system, utilisation of the on-board braking resistor and transmission losses in the grid can be reduced. This work gives the results of a case study on the Arnhem trolley-grid showing the potential of the implementation of stationary storage systems. Up to 17% of reduction in energy consumption can be achieved in some sections of this grid. Furthermore, a recommendation on sizing, location and operation of these systems is given