The impact of cross-regional clean energy dispatch on environmental welfare performance: Evidence from the west-east gas transmission project

As a landmark cross-regional infrastructure project in China, the West-East Gas Transmission Project (WEGP) aims to foster green development through optimized energy allocation. However, its comprehensive impact on economic, environmental, and social welfare remains to be assessed. Based on data from 279 prefecture-level cities in China (2003-2021) and treating the launch of the West-East Gas Pipeline Phase II as a quasi-natural experiment, this study employs a Hybrid-Network-DEA model to measure urban Environmental Welfare Performance (EWP), a Difference-in-Differences (DID) framework for causal identification, and spatial econometric models to further examine its spatial effects. The results show that the project significantly improved the EWP of node cities, primarily through energy substitution and welfare transformation effects. The effects are more pronounced in non-resource-based cities and central cities, and are strengthened by stringent environmental regulations. Furthermore, the project's impact exhibits spatial spillovers. These spillovers do not decay monotonically with distance but are jointly moderated by physical, economic, and institutional boundaries. This study provides systematic empirical evidence for evaluating the comprehensive benefits of large-scale green infrastructure and offers a research framework and policy insights for optimizing regional energy synergy and promoting inclusive green development.