An Interoperable EMS for the Provision of Grid Services with Hybrid Energy Storage Systems

This paper proposes an interoperable energy management system (EMS) for grid-connected HESSs, enabling the provision of ancillary services to the grid. Power systems are evolving towards a more renewable and decentralised structure, where energy storage systems (ESS) have emerged as a key energy asset to ensure the power balance and the system stability. In this context, hybrid ESSs (HESS) are an interesting solution because they take advantage of the dynamic properties of different ESS technologies. The proposed EMS structure ensures an adequate internal power allocation between the different ESS packs even when operating at power or state of charge limits. The proposed structure can be easily adapted and combined with specific control functions to provide a wide variety of grid services. Moreover, a power dispatch algorithm is included to allocate the power between the parallel power converters to maximise the system efficiency. The results from two representative use cases demonstrate the effectiveness of the proposed EMS to determine the operating setpoints of a modular HESS and to provide different grid-oriented services.