Quantile causality and dependence between renewable energy consumption, WTI prices, and CO emissions: new evidence from the USA.

This study investigates the Granger causal interplays between renewable energy consumption, WTI crude oil prices, and CO emissions in the USA using monthly data between January 1986 and May 2022. The study applies quantile-based techniques, namely, the quantile unit root test developed by Galvao (2009), the quantile cointegration test proposed by Xiao (2009), and the novel Granger causality-in-quantiles test suggested by Troster (2018). The results suggest that the series display a unit root across different quantiles and that the cointegration relationships exhibit heterogeneous behavior across quantiles. Regarding the causal linkages, the findings show: (i) a unidirectional causality from renewable energy consumption to oil prices, mainly at the lowest or highest quantiles of the distribution, (ii) a bidirectional causality between oil prices and CO emissions mainly in the middle and extreme quantiles, but there is evidence of causality from oil prices to CO emissions across the quantiles than in the reverse direction, and (iii) a unidirectional causality from renewable energy consumption to CO emissions at the lowest to medium and the highest quantiles. These findings have important implications for policy-makers.