Energy, followed by CO₂ emissions, is not only an environmental problem, but recognized as an economic, political and social strategic issue. In a global path of sustainable development, it is aware that achieving energy conservation as well as energy efficiency improvements is one of the most important and effective way to address climate change and energy challenges. The 2010 Report proposes the connotation as well as the measurements of energy efficiency based on a comprehensive study of international energy situation. It is well extended to several analyses such as the effects of economic structure on the macro energy efficiency, the difference between urban and rural residential energy consumption and characteristics of regional residential energy consumption, energy efficiency of major industries and sectors, the effects of fuel price on oil demand, energy efficiency policy design and simulation.