Considering the heterogeneity of different sub-sectors of clean energy, such as clean fuels, renewable energy and energy efficiency, this paper adopts the time-domain spillover index model, extreme spillover index model, and frequency-domain spillover model to analyze the spillover effects between sub-sector clean energy markets and traditional energy and metal markets under normal conditions, extreme conditions, and frequency-domain conditions. The empirical results highlight three interesting and noteworthy aspects: (1) Clean energy efficienc...
