BY:Hikmet Eliyev Optimal design of multi-energy systems with seasonal storage
The optimal design and operation of multi-energy systems, including seasonal energy storage, is often hindered by the complexity of the optimization task. Indeed, the description of seasonal cycles requires a one-year time horizon, while the operation of the system requires an hourly resolution; this turns into a large number of decision variables, including binary variables, when large systems are analyzed. This paper presents new methodologies for mixed integer linear programs that allow us to consider the annual horizon with hourly resolution, while at the same time significantly reducing the complexity of the optimization problem. Firstly, the validity of the proposed methods is verified by examining a simple system that can be solved in a reasonable calculation time without resorting to settlement days. The results show that the results of the proposed approaches are in good agreement with full-scale optimization, which allows you to correctly determine the size of the energy storage and manage the system with a long-term policy, while significantly simplifying the optimization task. In addition, the developed methodology has been adopted for the design of a multi-energy system based on the microdistrict in Zurich, Switzerland, which is optimized in terms of total annual costs and carbon dioxide emissions. Finally, the behavior of the system is revealed by analyzing the sensitivity of various characteristics of the energy system and studying the topology of the energy node along Pareto sets.