Deployment of rooftop photovoltaic systems at the urban scale based on multi-objective optimization from the life cycle perspective

Abstract

Solar photovoltaic (PV) systems are increasingly deployed on urban rooftops. The optimal deployment of solar PV systems in urban areas becomes important. Most optimization goals in the existing studies are expanding economic and environmental benefits. However, many studies take into account economic costs and benefits for only a few stages in the life cycle of solar PV systems, and the establishment of environmental benefit targets focuses more on the emission reduction stage. In addition, discrepant costs and benefits caused by building typology are often ignored in most optimization research at the city level. To address above limitations, this paper considers the whole life cycle of solar PV systems and introduces a multi-objective optimization framework for optimally deploying solar PV systems on different types of rooftops. Integrating building footprints and PV system parameters, the method determines the best locations and corresponding installed capacities of rooftop PV systems at the urban scale by simultaneously maximizing economic and environmental benefits. Various land use codes, power consumption modes, and key performance indicators are incorporated to evaluate the solutions of optimization. The approach enables scenario-based optimization of PV deployment considering evolving grid integration requirements. The method is applied to the six major urban districts of Nanjing, China. Results show that the optimized solar PV installed capacity can help meet 15 % of the household electricity demand and 7 % of industrial and commercial electricity demand. The investment payback periods of solar PV deployment on various types of buildings under different power consumption modes range from 6 to 13 years, while the energy payback periods remain consistently below 6 years. Different power consumption modes significantly influence the optimal installed capacity of an individual building. This study provides a comprehensive perspective on urban rooftop PV planning and offers practical insights for prioritizing rooftop PV development to achieve sustainable goals.