经济政策不确定性对中国新能源产品出口的动态影响研究——基于TVP-VAR模型的实证分析

Dynamic Impact of Economic Policy Uncertainty on China’s New Energy Product Exports—An Empirical Analysis Based on the TVP-VAR Model

摘要: 2008年全球金融危机以来，主要经济体经济政策不确定性(EPU)持续处于较高水平，对全球贸易格局产生了重要影响。文章基于2015年1月至2025年4月的月度数据，运用时变参数向量自回归模型(TVP-VAR)，考察美国EPU对中国锂电池、新能源汽车及光伏产品出口的动态冲击效应。研究发现：第一，有别于传统贸易理论预期，美国EPU与中国新能源产品出口之间存在正向关联，文章将其概括为适应性正向响应机制，其可能根源在于新能源产品的技术不可替代性、绿色外部性及中国供应链的稳定性优势；短期前置出口行为可能通过产能锁定效应与技术学习曲线效应转化为中长期竞争优势，但该转化以产业具备足够技术壁垒与成本优势为前提。第二，产品响应存在异质性，新能源汽车对EPU冲击最敏感(格兰杰检验P = 0.010)，光伏产品次之(P = 0.034)，锂电池较弱(P = 0.054)，这与三类产品在产业链位置、市场结构与政策环境上的差异有关。第三，等间距与分时点脉冲响应分析表明，EPU的正向影响可能具有中长期累积效应与时变增强态势，自2018年至2024年间响应强度呈上升趋势；但也需注意，时变增强可能部分反映了产业基本面变化与供给能力扩张的叠加效应，正向关联中可能存在竞争性解释。研究拓展了EPU与国际贸易的理论认知，为理解不确定性环境下新能源产品出口的动态调整机制提供了经验参考。

Abstract: Since the global financial crisis of 2008, economic policy uncertainty (EPU) in major economies has persisted at elevated levels, exerting significant effects on the global trade landscape. Based on monthly data from January 2015 to April 2025, this paper employs a time-varying parameter vector autoregression (TVP-VAR) model to examine the dynamic impact of U.S. EPU on China’s exports of lithium-ion batteries, new energy vehicles, and photovoltaic products. The findings are as follows: First, contrary to the predictions of conventional trade theory, a positive association exists between U.S. EPU and China’s new energy product exports. This paper conceptualizes this phenomenon as an adaptive positive response mechanism, which may stem from the technological irreplaceability of new energy products, their green positive externalities, and the stability advantages of China’s supply chain. Short-term front-loading export behavior may translate into medium- to long-term competitive advantages through capacity lock-in effects and technological learning curve effects, though such conversion is contingent upon industries possessing sufficient technological barriers and cost advantages. Second, product-level responses exhibit heterogeneity: new energy vehicles are most sensitive to EPU shocks (Granger causality test P = 0.010), followed by photovoltaic products (P = 0.034) and lithium-ion batteries (P = 0.054), which is attributable to differences across the three product categories in their positions along the industrial chain, market structure, and policy environment. Third, equi-spaced and time-specific impulse response analyses indicate that the positive effect of EPU may exhibit medium- to long-term cumulative dynamics and a time-varying intensifying tendency, with response strength showing an upward trend from 2018 to 2024. It should be noted, however, that the time-varying intensification may partially reflect the compounding effects of changes in industrial fundamentals and expansion of supply capacity, and competing explanations may exist for the observed positive association. This study extends the theoretical understanding of the relationship between EPU and international trade, providing empirical evidence for understanding the dynamic adjustment mechanisms of new energy product exports under uncertainty.