Assessing the internal nexus of energy transition at the global level: Insights from triple aspects of scale, structure, and efficiency

This paper assesses the long-term relationships between total primary energy supply (TPES), renewable energy consumption (REC), and energy efficiency (EE) at the global level. The objective is to assess the role of renewable energy (RE) substitution in energy transition (ET) from the perspective of scale, structure, and efficiency. Utilizing panel data from 100 countries spanning the period from 2000 to 2018, we employ causality tests to explore the interconnections and potential causal links among TPES, REC, and EE. The PMG estimation results reveal that both TPES and REC exert a sustained positive impact on improving EE, a conclusion supported by various robustness checks. Granger causality tests further reveal bidirectional causality among the three variables. Heterogeneity analysis highlights that REC and TPES contribute more significantly to EE in trade-restricted, institutionalized, high-income, and OECD countries. Notably, while REC exerts short-term negative effect on EE in OECD nations, its long-term impact remains negligible in countries with weaker institutional environments. These findings provide critical insights into the role of RE in EE improvement and offer policy recommendations for enhancing renewable energy substitution in global sustainable development.