Spatial spillover effects of green public investment on regional sustainable development: An analysis based on spatial econometric models

This study explores the spatial spillover effects of government-led green public investment (GPI) on regional sustainable development, focusing on the heterogeneous mechanisms of renewable energy infrastructure investment (REI) and ecological protection project investment (EPI). Based on a "economy-environment-society" three-dimensional evaluation framework, we use panel data of 30 Chinese provinces (2010–2022) and adopt the Spatial Durbin Model (SDM), combined with instrumental variable (IV) and System GMM methods to address endogeneity. The results show that: (1) GPI exerts a significant positive direct effect and spatial spillover effect on regional sustainable development; (2) The spillover effects are heterogeneous: REI contributes more to economic growth through cross-regional energy industrial chains, while EPI has a stronger impact on environmental quality via ecological connectivity; (3) Inter-regional industrial linkage and technological innovation diffusion are the core transmission channels. Additionally, the spillover effect is more prominent in the economic and environmental dimensions in eastern China, and in the social equity dimension in central and western regions. This study enriches the literature on spatial spillover effects of green public investment by distinguishing the heterogeneous mechanisms of REI and EPI, providing precise empirical support for differentiated green fiscal policies and coordinated regional sustainable development.