Topological analysis, endogenous mechanisms, and supply risk propagation in the polycrystalline silicon trade dependency network

Abstract

High-purity polycrystalline silicon, as a core raw material in the photovoltaic industry, has a trade structure whose robustness affects the supply security of the entire photovoltaic industry. Using social network analysis methods and dependence indicators, this study constructs a Polycrystalline Silicon Trade Dependency Network (PSTDN) from 1995 to 2019, and performs descriptive statistical analysis and trade community divisions on the network. The Temporal Exponential Random Graph Model (TERGM) is used to explore the factors influencing the formation of trade dependencies. Based on the cascading failure model, a Photovoltaic Multilayer Network Supply Risk Propagation Model (PMNSRPM) is constructed to study the risk propagation process of polycrystalline silicon supply interruption as a raw material in the photovoltaic industry. Finally, using the risk propagation range and dependency degree, the study measures the importance of nations comparatively. The results show that (1) the PSTDN exhibits reciprocity, geographical clustering, and weak network convergence; (2) the evolution of the PSTDN's community has gone through three stages: the rising expansion phase from 1995 to 2007, the crisis recession phase from 2008 to 2010, and the competitive contraction phase from 2010 to 2019; (3) the evolution of the PSTDN shows strong reciprocity effects, transitive effects, stabilization effects, and lag effects as endogenous mechanisms; (4) the average risk propagation range is continuously increasing along the supply chain, while there is no significant difference in the risk propagation rate along the supply chain. The risk propagation rate of different risk sources shows a long-tail effect, with the risk propagation rate of leading countries like the United States and China growing rapidly over time. The United States can infect China, but China cannot infect the United States and Western Europe; (5) The risk propagation range and the dependency degree present a positive correlation ranging between 0.5 and 0.7, which is not as highly positive as initially anticipated, and the correlation between them shows a downward trend. This study explores the statistical characteristics of the PSTDN, community evolution, and evolutionary factors, demonstrates the importance of polycrystalline silicon supply security for the production of the photovoltaic industry, quantifies the risk propagation capabilities of different countries, and identifies a group of countries that actually have a high risk propagation range but tend to be underestimated due to their low dependency degree in normal trade network. This can help enhance the early warning capabilities for photovoltaic supply security risks of various countries.