Dual dividends of multilateral energy cooperation: Renewable investment surge and air quality improvements under the Belt and Road Energy Partnership

The Belt and Road Energy Partnership (BREP) represents a pivotal mechanism for advancing energy transition, yet its capacity to catalyze renewable investments and environmental co-benefits remains underexplored. Using panel data from 108 countries (2000–2021) sourced from the World Bank's WDI and China Global Investment Tracker (CGIT), this study employs a quasi-experimental difference-in-differences (DID) approach with robustness verifications (e.g., PSM-DID, placebo tests) to quantify BREP's impacts. Results reveal that BREP participation induces an 11.81 % average surge in renewable investments and reduces PM2.5 concentrations by 17.96 % relative to non-participating countries. Heterogeneity analyses confirm stronger effects in high-emission, BRI participating, and developing economies. Furthermore, BREP has the potential to indirectly promote renewable energy investments by the international cooperation effect and innovation drive effect. These insights advance the theoretical foundations of multilateral energy governance through quantifying co-benefit mechanisms linking infrastructure cooperation with environmental outcomes, while providing policymakers with empirical benchmarks to design next-generation climate partnerships under the Belt and Road framework—specifically for refining technology diffusion protocols and tailoring differentiated implementation strategies.