Assessing energy transition in major carbon emitting countries using decomposition logic

This study examines whether the recent expansion of non-fossil energy in the world’s top 20 CO 2 -emitting economies signifies a structural transition of energy systems or the continued growth of overall energy supply. We used a system-level framework based on total primary energy supply, to distinguish between fossil fuel displacement and demand-driven energy addition. A decomposition approach is used for separating changes in fossil energy into demand growth (activity) and fuel substitution (growth) effects. This is supported by twoindicators - fossil displacement ratio and demand absorption ratios. The findings from 2015 to 2023 data reveal substantial variations across sample countries. Most economies have added non-fossil energy, however fewer than half could use this addition to substitute absolute fossil energy use. In many emerging economies, renewable expansion partially accommodated rising energy demand, consistent with the “energy addition” perspective. These results emphasize the use of absolute metrics in evaluating decarbonization progress rather than just tracking the share of renewables.