Bi-Level Optimal Configuration of Multi-Building Flexible Interconnected Energy Systems Considering Multi-Energy Complementarity

Flexible interconnection among different building types holds significant importance for integrating distributed energy resources, mitigating regional load peak-valley differences, and enhancing the local consumption capacity of renewable energy. Addressing the issue of insufficient multi-energy synergy in multi-building clusters, this paper proposes a bi-level optimal configuration method for flexible interconnected energy systems that accounts for multi-energy complementarity. By constructing a comprehensive multi-energy flow model encompassing all elements of source, network, load, storage, and conversion, a bi-level optimization framework is established. The upper level aims to minimize total lifecycle cost and carbon emissions, while the lower level targets maximizing the renewable energy self-consumption rate and minimizing daily operational cost. An improved NSGA-II algorithm integrating Lévy flight and a good point set is employed for an efficient solution. Simulation results demonstrate that the proposed scheme can achieve cross-spatiotemporal energy transfer and multi-energy collaborative optimization. In a typical summer day scenario, the system’s renewable energy self-consumption rate increased to 96.20%, operational cost was reduced by 8.83%, and carbon emissions decreased by 10.18%, validating the effectiveness and superiority of the method in improving energy utilization efficiency and supporting the low-carbon and economic transition of regional building systems. The outcomes of this study can provide theoretical support and engineering reference for the low-carbon, economical, and efficient planning of multi-building energy systems.