Optimization of Distributed Energy System Operation in All-Electric Districts with Electricity Sharing

In recent years, as renewable energy has been increasingly deployed in pursuit of a decarbonized society, photovoltaics (PV) have become particularly widespread in the residential sector owing to their ease of installation. However, because PV output fluctuates with solar irradiance, it is difficult to ensure a stable power supply with PV alone. It is therefore effective to configure a distributed energy system (DES) that combines PV with energy storage equipment such as battery (BT) and heat pump water heater (HPWH). In addition, electricity sharing among households has attracted attention as a means of maximizing the utilization of PV-generated electricity. Furthermore, comprehensive control of the operation of these systems is expected to improve the electricity self-sufficiency of individual households and the district as a whole, thereby reducing environmental impact. In this study, we consider a district model composed of multiple dwellings equipped with a DES integrating PV, HPWH, and BT, and introduce electricity sharing by numerical simulation while optimizing the operation schedules of the system. The target region is assumed to be Japan, and two optimization objectives are defined (1) minimization of primary energy consumption and (2) minimization of running cost and the corresponding results are compared. System optimization is performed using a mixed-integer linear programming (MILP) formulation. As a result, in scenario (1), the introduction of electricity sharing reduces weekly primary energy consumption by approximately 5%. In scenario (2), it is shown that the control outcomes, including how PV-generated electricity is utilized, change significantly depending on given conditions such as the selling price of exported electricity. These findings clarify both the potential of DES and electricity sharing to reduce environmental impact and the effectiveness and limitations of the proposed optimization method.