EV’s as energy storage on urban light rail systems — a synergy of requirements

The increasingly urgent need to decarbonize transport is leading to a much greater uptake of electric vehicles (EVs) in countries across the world. Also, the installation and use of urban light rail systems (trams) is seen as a way of breaking the reliance of commuters on the internal combustion engine, and therefore car ownership. Due to the simplicity of design, most conventional tram systems use unidirectional substations to draw power/energy from the utility supply. Due to their very nature, the substations are not able to return excess regenerated energy from the trams back into utility supply, with this energy often being dissipated in dump resistors onboard the trams to prevent over-voltages on the tram system. This paper explores the possibility of using EV’s as temporary trackside energy storage systems on urban light rail systems through the use of bi-directional connection interfaces (chargers), which allow use of the vehicle battery in typical V2X scenarios. The paper uses the city of Sheffield (UK) Supertram network as an example network on which the effect of EV energy storage could be studied.