The present study explores the important contributors of energy efficiency in OECD countries, by taking the energy intensity and carbon intensity as a proxy of energy efficiency. Notably, we study the role of three indicators of export diversification (export product diversification, extensive margin and intensive margin) for energy intensity and carbon intensity in 29 OECD countries, which further allow us to draw new and innovative conclusions. In doing so, we use the data from 1990 to 2015 and employ alternative panel data estimations; sequential estimation, panel quantile regressions, system GMM and difference GMM, for an in-depth and detailed empirical analysis. In our empirical analysis, we robust check the impacts of export diversification on carbon intensity and investigate the role of institutional factors for energy intensity. The empirical outcomes provide robust evidence that all three indicators of export diversification help to reduce energy intensity and might be used as a policy factor in improving energy efficiency and sustainable environment. The empirical evidence further reports practical implications for policymakers and environmental scientists to achieve the greener growth, energy efficiency and sustainable development goals (SDG's) of OECD countries.

本研究以能源强度和碳强度作为能源效率的代用，探索了经合组织国家能源效率的重要贡献者。值得注意的是，我们在29个经合组织国家中研究了出口多样化的三个指标（出口产品多样化，广泛的边际收益率和集约性边际收益）对能源强度和碳强度的作用，这进一步使我们得出了创新的结论。在此过程中，我们使用了1990年至2015年的数据，并采用了其他面板数据估算方法；顺序估计，面板分位数回归，系统GMM和差异GMM，以进行深入而详细的经验分析。在我们的经验分析中，我们有力地检查了出口多元化对碳强度的影响，并研究了制度因素对能源强度的作用。实证结果提供了有力的证据，出口多样化的所有三个指标都有助于降低能源强度，并且可以用作提高能源效率和可持续环境的政策因素。经验证据进一步报告了决策者和环境科学家实现经合组织国家的绿色增长，能源效率和可持续发展目标（SDG）的实际意义。