Assessing flexibility in networked multi-energy systems: A modelling and simulation-based approach

In response to the uncertainty and volatility arising from renewable sources, there is a growing need for enhanced flexibility within the energy system to maintain a continuous balance between power generation and demand. In this context, interest is growing around the so-called Multi-Energy Systems (MES) where different energy vectors coexist and optimally interact through conversion technologies and energy networks, creating additional flexibility opportunities. Nevertheless, there exists a gap in research regarding the impact of the network on flexibility availability. Typically, these complex systems are treated as power nodes or energy hubs without comprehensive network considerations. For this reason, the paper aims to propose a methodology and a tool to evaluate flexibility in a Multi-Energy System, considering not only the individual devices in place and the users' demands but also their interactions with the physical energy network. In detail, a simulation-based methodology is developed and described, and finally tested on a Case Study. As a result, both the physical and operational flexibilities (UP-flex and DOWN-flex) of the system regarding the electrical vector were obtained analytically and graphically. Particular attention was given to the evolution of key temperatures within the district heating network and the thermal power produced by the central unit in various flexibility scenarios. The outcomes demonstrate the utility of this tool for defining flexibility boundaries and profiles, as well as for assessing whether the flexibility demanded by grid operators aligns with the physical constraints of the network.