Renewable energy development and carbon productivity in OECD countries: A new perspective on the internal mix of renewable energy

Achieving environmental sustainability and economic growth demands higher carbon productivity. While much literature discusses the impact of renewable energy scale and penetration on carbon productivity, the specific effects of the internal structure of renewable energy sources are not well understood. This study explores the influence of the renewable energy internal structure on carbon productivity in 35 selected OECD countries. The main results are as follows: (1) The gradual diversification of the renewable energy mix has a U-shaped relationship with carbon productivity. Almost half of the countries have passed the turning point. This "U-shape" relation exists across all quantiles with little variation in inflection points. (2) The diversification of the renewable energy mix impacts carbon productivity through non-linear scale and structural effects, as well as linear technology effects. (3) The growing differentiation in the renewable energy mix among countries has a negative impact on carbon productivity, and this adverse effect is more significant in countries with higher carbon productivity levels. These findings provide valuable insights for OECD countries to optimize the internal mix of renewable energy for promoting carbon productivity. They emphasize the importance of considering the internal structure of renewable energy sources in formulating renewable energy development policies. Specifically, due to the non-linear relationship between renewable energy structural diversification and carbon productivity, countries at different levels of diversification can adopt distinct renewable energy development strategies.