The Spatial Spillover Effect of the Energy Use Rights Trading Policy on Urban Green Total-Factor Energy Efficiency

Sustained enhancement of energy utilization efficiency constitutes a pivotal lever for achieving dual carbon goals. To examine both the local effects and spatial spillovers of the Energy-use Rights Trading System (ERTS) on urban green total factor energy efficiency (GTFEE), this study employs the super-efficiency EBM-GML index to measure GTFEE across 270 prefecture-level cities in China from 2013 to 2022. Utilizing a Spatial-DID model, we find that the ERTS significantly drives local GTFEE improvements, with the positive effect intensifying over time, while concurrently exerting a negative spatial spillover on GTFEE in neighboring cities. Mechanism analysis suggests that the ERTS enhances local GTFEE through increased R&D investment, optimized fossil energy structures, and improved energy resource allocation in pilot cities, yet suppresses GTFEE improvement in adjacent areas via reduced R&D investment, a worsening fossil energy structure, and resource misallocation. These patterns are consistent with cross-regional flows of R&D resources and energy-intensive industries between pilot and non-pilot cities. Heterogeneity tests reveal that the policy’s effects on pilot city GTFEE are more pronounced in cities with larger populations, stronger industrial bases, more abundant human capital, greater resource endowments, and more transparent environmental information disclosure. Moreover, the population size of pilot cities intensifies the negative spatial spillover effect on neighboring GTFEE, whereas a well-established industrial base in pilot cities mitigates such adverse spillovers. It should be noted, however, that the Spatial-DID model is sensitive to the specification of spatial weights, and the mechanism analysis can only provide indirect evidence of cross-regional factor and industrial mobility. These findings offer spatial-effect empirical evidence to inform the further refinement of the ERTS under the dual carbon framework.