Assessing the role of renewable-based energy innovation, economic growth, and political risk in shaping Japan's load capacity factor: A wavelet-based quantile analysis

Understanding how renewable-based-energy innovation influences ecological sustainability remains a critical yet underexplored issue. This study fills this gap by examining the effects of renewable-based-energy innovation, political risk, and economic growth on load capacity factor (LF) in Japan. It further advances existing literature through a disaggregated analysis of renewable-based-energy innovation specifically solar, wind, and biomass innovation, to assess their individual environmental impacts. Given the non-normal distribution of the dataset and the need to capture heterogeneous relationships, this study used recently introduced wavelet based-quantile methodologies: wavelet-quantile Phillips-Perron, wavelet-quantile regression and wavelet-quantile correlation. The empirical results indicate that biomass and solar innovations enhance ecological quality by increasing LF across all quantiles and horizons, while economic growth reduces ecological quality, reflecting ongoing environmental pressures from expansion. Wind innovation shows a negative short-term impact but becomes beneficial in the medium and long terms, reflecting technological gains. Conversely, political risk exerts mixed short-term effects but negatively affects ecological quality in the long term, indicating that persistent instability undermines environmental governance. These findings emphasize the need to expand investment in biomass and solar technologies, introduce short-term support for wind energy to manage initial ecological costs, and strengthen political and institutional stability for sustained ecological gains.