Urban density and residential solar adoption: evidence and theory

Residential solar photovoltaic (PV) systems have emerged as a key source of household energy consumption, contributing to urban sustainable development. Contrary to the commonly observed monotonic negative relationship between urban population density and PV installation, this study identifies an inverted U-shaped relationship. Based on the empirical evidence, we further develop an urban model that incorporates residential PV adoption to explore two opposing effects of population agglomeration. On one hand, agglomeration reduces installation costs, thereby promoting PV adoption; on the other hand, it leads to more households residing in high-rise buildings, where residential PV installation is often unfeasible. The varying trade-offs between these two effects across different population densities give rise to the observed non-monotonic pattern.