Rethinking energy security in China: Multi-dimensional measurement and spatiotemporal dynamics

Energy security is essential for ensuring economic stability and ecological sustainability, and it is particularly critical for China as it advances toward high-quality development. This paper constructs a multidimensional energy security index using functional data analysis, which enables continuous tracking of indicator trajectories and captures evolutionary dynamics that traditional static methods fail to reflect. By integrating the functional entropy weight method, kernel density estimation, Theil index decomposition, and convergence models, the study systematically examines China's energy security from 2004 to 2022. Results show that the weights of different dimensions change substantially over time: supply security remains dominant (0.41–0.67), environmental security declines before rising (0.04–0.17), social security increases then decreases (0.05–0.15), and economic security fluctuates cyclically (0.11–0.37). At the national level, energy security improves overall, increasing from 0.044 in 2004 to 0.055 in 2022, though with clear spatial heterogeneity. At the provincial level, the energy security level of Shanxi (0.127), Inner Mongolia (0.116), and Shaanxi (0.110) ranked in the top three in 2022. These findings underscore the need to balance supply and environmental priorities, optimizing resource allocation, and adopt region-specific strategies to promote coordinated and stable energy security.