Energy Use and the Consumption-Based Ecological Footprint in Sustainability Assessment: Heterogeneous Common-Factor Evidence from a 44-Country Panel

Sustainability assessment increasingly requires consumption-based indicators that attribute environmental pressures to final demand rather than only to the place of production; however, the total ecological footprint also includes carbon uptake land, creating potential accounting overlap with energy use. This study estimates conditional associations between the consumption-based ecological footprint per capita, income, aggregate energy use per capita, trade openness, and broad institutional quality in a balanced 44-country panel from 2003 to 2022. A parsimonious static Common Correlated Effects Mean Group (CCEMG) model is the reference levels specification, complemented by first-difference CCEMG, Augmented Mean Group, two-way fixed effects with Driscoll–Kraay inference, and Dynamic Common Correlated Effects (CCE). The static basic energy coefficient is 0.2673 (standard error [SE] = 0.0923, p = 0.0059), while the regulatory-quality extension gives 0.2988 (SE = 0.1175, p = 0.0146). The basic first-difference estimate is 0.2269 (p = 0.0145), whereas the fully augmented Dynamic CCE estimate is 0.1470 (p = 0.3520). New finite-T diagnostics show that all country designs are full rank, but the median standardized condition number rises from 75.15 in the basic static model to 214.42 in the fully augmented dynamic model as residual degrees of freedom fall from 12 to 6. Excluding the least-precise quartile of country slopes does not weaken the positive static mean, and leave-one-year-out estimates remain positive in every omission. Replacing regulatory quality with Worldwide Governance Indicators (WGI) rule of law yields an energy coefficient of 0.3294 (p = 0.0075). Exploratory Spearman tests do not link national energy coefficients to the available country-average structural covariates. Westerlund evidence remains mixed, formal U-shape tests do not support an Environmental Kuznets Curve, and national coefficients are widely dispersed. The evidence is therefore sign-consistent but statistically specification-sensitive and does not identify a causal, non-carbon, or universal policy elasticity. For sustainability research, these results show that energy-related ecological pressure should be assessed through consumption-based accounting and country-specific heterogeneity rather than translated into a universal energy-reduction target.