Carbon mitigation potential of building-integrated photovoltaics across diverse urban structures and climate zones in China

Photovoltaic systems can reduce carbon emissions from buildings, but their potential varies with climate, building form and usable installation area. Understanding these differences is important for planning low-carbon cities. Here we assess the carbon mitigation potential of building-integrated photovoltaic systems across China using a numerical model that combines rooftop and south-facing facade suitability with building type, climate zone and electricity-demand scenarios. We examine how stricter or more relaxed suitability rules affect the area available for installation and the resulting avoided carbon dioxide emissions. Rooftops generally provide the largest mitigation potential, while south-facing facades contribute increasingly as suitability rules are relaxed. Annual mitigation ratios range from 3% to 27%, with low-rise buildings showing higher ratios than high-rise buildings. During warm periods, mitigation varies strongly by climate zone, whereas cold-period mitigation is less sensitive to climate or scenario. The results suggest that colder cities may achieve substantial photovoltaic mitigation benefits. Low-rise urban structures have higher carbon mitigation potential from building-integrated photovoltaics than high-rise structures, according to differential analyses across climate zones and urban structures in China