Price volatility spreaders in China's coal market in the carbon neutrality context: an evolution analysis based on a transfer entropy network and rank aggregation

Abstract This paper investigates China's coal price volatility spreaders (CPVSs) from the supply side to locate the volatility source since coal price volatility may destabilize many downstream products' prices or even bring uncertainties to macroeconomic output. Especially in the carbon neutrality context, China's coal market is being reconstructed and responding to imbalances between supply and demand; identifying the CPVSs helps alleviate rising market instability and prevent energy-induced system risk. To achieve this objective, we explore causalities among 938 weekly coal prices reported by different coal-producing areas of China from 2006.9.4 to 2021.7.12 using the transfer entropy method. Then, coal price volatility influence is quantified to identify the CPVSs by conjointly using complex network theory and a rank aggregation method. The validity test demonstrates that the proposed hybrid method efficiently identifies the CPVSs as it correlates to many price determinants, e.g., electricity and coal consumption and generation. The empirical results show that causalities among coal prices changed dramatically in 2016, 2018, and 2020, affected by coal decapacity and carbon neutrality policies. Before 2018, coal-producing provinces with strong demand for coal and electricity, e.g., Jiangxi, Chongqing, and Sichuan, were CPVSs; after 2019, those with comparative advantages in coal supply, e.g., Gansu and Ningxia, were CPVSs. Overall, the coal market is unstable and sensitive to energy policy and external shocks. Policymakers and market participants are recommended to monitor and manage the CPVSs to improve energy security, avoid policy-induced instability and prevent risks caused by coal price fluctuations.