Social development effect of China's investment in energy infrastructure in countries along the Belt and Road

Energy infrastructure connectivity is widely recognized as a key component of the Belt and Road Initiative (BRI), yet whether and how China's energy infrastructure investment promotes social development in recipient countries remains an open question. To investigate this, we first employ system GMM and threshold regression, and then mediating effect models using panel data from 64 BRI countries over the period 2005–2024. The results show that China's energy infrastructure investment significantly improves the Human Development Index (HDI) of recipient countries, though with a time lag. This effect is stronger in countries with better government governance, stronger energy resource endowments, and higher existing infrastructure levels, and is more pronounced for state-owned enterprises than for non-state-owned ones. In terms of mechanisms, the impact operates through a direct pathway, which provides basic energy services and improving production efficiency and an indirect pathway by enhancing capital formation, creating employment opportunities and improving education and healthcare outcomes. Together, these pathways represent a sustainable "hematopoietic" (self-generating) function rather than a simple "transfusion" approach. Our findings offer policy insights for governance cooperation, investment diversification, and balancing social development with carbon emission goals under the BRI framework.