A System of Systems Approach to Reliability-Oriented Planning of People-Centric Smart City Energy Infrastructure: A Bilevel MILP Formulation

Abstract

This article premises the notion of portraying a smart city energy infrastructure (SCEI) from a people-centric bottom-up view. This is concluded by a system of systems approach in which the coordinated collections of autonomous microenergy hubs construct macroenergy hubs as SCEI in a decentralized manner. Moreover, a reliability-oriented framework is introduced, complying with the performance requirement of customer satisfaction from the people-centric view. Since electric energy as a unique commodity is traded within a continuously operated system, reliability becomes an objective from the start of the planning process (i.e., reliability-oriented planning) while still achieving the performance (technical and quality) requirements demanded nowadays. Hence, the proposed reliability-oriented framework tends to improve customer interruption cost and cost of energy not supplied in the objective function, as well as the Electrical energy index of reliability (EEIR) and system average interruption frequency index as indices for both heat and electrical loads. In the proposed framework, all constituent systems collaborate to create a more functional and reliable SCEI, while each independent system intends to increase its benefit. Furthermore, the proposed framework is formulated as a bilevel mixed-integer linear programming planning problem. This bilevel formulation suffers from nonconvexity in its lower level problem. Therefore, it is transformed into a single-level problem through binary constraint relaxation and primal–dual reformulation. The effectiveness of the proposed model is demonstrated by implementing it to the Dättwil district (Switzerland) as a real urban case study system. Simulation results confirm the effectiveness of the proposed approach due to considerable improvement in reliability performance (5.2% in EEIR, 95% in electrical system average interruption frequency index, 0.1% in heat energy index of reliability (HEIR), and 56% in heat system average interruption frequency index), SCEI-to-grid performance (81% in export to import ratio), and sustainability performance (77.8% in emission and 4.8% in energy loss).