Exploring the endogenous structure and evolutionary mechanism of the global coal trade network

The uneven distribution of global coal supply and demand markets has driven coal trade. Effectively characterizing the global coal trade pattern and exploring its evolutionary mechanisms are important for economic development and international energy security. Therefore, this study adopts complex network methods to construct global coal trade network (GCTN) from 1995 to 2021. Based on exploring the overall, individual, and motif structural characteristics of the network, the temporal exponential random graph model is adopted to explore the impact mechanism of endogenous and exogenous variables on the evolution of the GCTN. The research findings demonstrate that (1) at the overall level, the network size, closeness, accessibility, and reciprocity of global coal trade exhibit an increasing trend; (2) at the motif level, aggregation and bilateral reciprocity are the primary trade patterns that affect the formation and evolution of the GCTN that is different from the steady-state structures of the four common super-families and possesses unique characteristics; (3) at the individual level, the United States and European economies possess a higher degree of diversification in coal trade, while Australia and emerging economies exhibit higher coal export trade volumes. The RCEP economies, represented by Japan and South Korea, possess a higher import share. Additionally, the Netherlands plays a "transit station" role in the network; (4) the formation and evolution of the GCTN are influenced by endogenous mechanisms. Reciprocity, transmission closure, and convergence effects have a significant promoting effect on network construction. Ignoring endogenous mechanisms can lead to significant bias in empirical results.