A quantile analysis of energy efficiency, green investment, and energy innovation in most industrialized nations.

The continuous use of fossil fuels to meet the energy demands of the industrialized nations has led to environmental degradation. As such, there has been a call for research, exploration, and the usage of alternative energy which is believed to improve the depleting quality of the environment. This study investigates the relationship between energy efficiency, green energy investment, and energy innovation in a panel of nine highly industrialized countries, namely Canada, Japan, France, Spain, Germany, Switzerland, Italy, the USA, and the UK. Relying on the environmental Kuznets' hypothesis (EKC), we employ the quantile-on-quantile regression approach to the data obtained between 1980 and 2018. The empirical estimates validate the EKC hypothesis in most of these industrialized nations considered. The findings also reveal that the continuous use of non-renewable energy consumption escalates emissions, while the use of renewable energy reduces the level of emissions "in" the environment. Therefore, energy efficiency leads to an increase in emissions in the first 3 quantiles and reduces emissions in the remaining quantiles. Also, energy innovation leads to a high amount of emissions. Finally, the study calls for increased investments in renewable energy as well as energy efficiency to ensure continuous improvement in the quality of the environment.