Which Energy-Transition Policies Improve Energy Security? Evidence from Policy-Instrument Decomposition and Cross-Country Panel Models

Energy security has become a central policy challenge because decarbonisation must be achieved without weakening the reliability, affordability and resilience of national energy systems. This article examines whether and how energy transition policies contribute to national energy security, with particular attention to aggregate policy stringency, individual policy instruments, and renewable electricity deployment. The analysis uses a panel of 49 countries over 23 observed years between 2000 and 2023, excluding 2002, comprising 1127 country-year observations, and applies two-way fixed-effects models with Driscoll–Kraay standard errors. The aggregate Energy Policy Stringency Index has a positive but statistically insignificant coefficient in the contemporaneous model (0.421) and remains insignificant with one-, two- and three-year lags (0.187, 0.128 and –0.026, respectively). Renewable electricity generation is consistently positive and significant, with coefficients ranging from 0.071 to 0.090, indicating that actual renewable deployment is more closely associated with energy security than formal policy stringency. Policy-instrument decomposition shows that fossil fuel excise taxes have the strongest positive association, with coefficients from 1.554 to 1.082 in full-instrument models and from 1.614 to 1.077 in one-by-one robustness checks. Air emission standards have delayed positive effects, while some renewable-support and cross-sectoral tools show mixed results, indicating dependence on design and system readiness.