An extended battery equivalent circuit model for an energy community real time EMS

Smart Grids (SGs) represent a prominent energy efficiency strategy in the fight against Climate Change. In 2018, with RED II, the European Union made SGs realization more concrete thanks to the definition of Renewable Energy Communities (RECs), i.e. local electrical grids equipped with Renewable Energy Generators (REGs) and batteries. REC participants receive incentives proportionally to the green energy they share, aiming at more affordable technology. Therefore, proper Energy Management Systems (EMS) are required to minimize energy losses and costs to exploit accurate real-time power forecasting. In this context, battery management plays a crucial role because of its function as an energy buffer and its not negligible costs. That said, fast and accurate battery models are needed to synthesize realistic EMSs from the perspective of efficient embedding in the field. Equivalent Circuit Models (ECM) offer speed, reasonable accuracy and good explainability as grey-box models. In this work, a Thevenin ECM is synthesized with the aim of increasing realism in a REC EMS model, which relies on a simple battery linear model. The above ECM objective is to achieve flexibility and embedding suitability. First, one single trained model is synthesized for different ambient temperatures, and, secondly, promising results towards only one set of optimal parameters (instead of two, one for charging and one for discharging) are optimized, leading to possible future developments aiming at a faster and more general battery model for online EMS applications. The EMS results from simulations with the new ECM model are compared to the previous linear battery model, showing that the ECM model does not compromise the REC EMS thesis according to which auto-consumption is worse than a cost-minimization-oriented solution.