The subject of research in the present Metro-HESS project is a hybrid energy storage system (=HESS) for the use of braking energy in urban subway railroads based on the example of the Athens metro. Here, the electrical energy generated during the braking process is to be used to supply the 420 V AC network of the individual stations and thus be used for stationary consumers such as lighting, ventilation and elevators or escalators. The higher-level goal of this consideration is to reduce energy consumption and thus save greenhouse gases that are harmful to the climate, but also to reduce operating costs. To this end, it is expected that such a storage system will be able to cover a significant portion of the stations' energy consumption (in the order of 75%). In the process, the storage unit will be charged periodically at high power levels.
Within the framework of the feasibility analysis, a demonstrator system is to be built and tested. In addition to the concrete case study, the project will also specifically develop and improve methods that can be applied to different use cases. For this purpose, the focus will be on a method for the conceptual design and dimensioning of hybrid storage systems. Furthermore, the different requirements for the energy management system are to be compared with the help of simulations and examined for applicability to the case study. On this basis, a suitable concept for energy management will be developed. In particular, information from the railroad control system regarding forecasts can be taken into account.