ECONO MIC CONCEPTS OF ENERGY EFFICIENCY ? A REVIEW

Energy security is the core of sustainable energy development. Energy efficiency is furthermore an important measure to ensure national energy supply security. According to the investigation of the number of production factors, energy efficiency indicators may be roughly divided into single - factor energy efficiency (SFEE) and total - factor energy efficiency (TFEE). SFEE m eans the ratio between the effective output and the energy input of an economy, while the energy consumption per unit of GDP (gross domestic product) is typically used as its index. TFEE, on the base taking into account the combination of multiple factors of various social inputs (i.e., capital, labor, energy, etc.), gets the efficiency frontier using statistical analysis method. In recent years, TFEE has been widely applied to the study of energy efficiency, while data envelopment analysis (DEA) is the mor e popular method to analyze TFEE currently. The purpose of this research is to comprehensively study the economic concepts of above - mentioned energy efficiencies, from development history, theoretical models, and literature review, their advantages and dis advantages are analyzed by comparisons, and the future directions of development are set forth as well.