Policies of energy efficiency: problematic, means and tools of assessment

As energy efficiency has become one of the main issues and even a pillar of energy policies and policies of struggle against climate change, this article discusses the various aspects of this issue which may also mean energy savings in some situations. Thus, energy efficiency encompasses all changes associated with a decrease of the energy required to produce an economic activity unit, or to obtain a given level of comfort. Implementing public policies for energy efficiency supposes the adoption of means of action aimed at acting on the different levers of energy efficiency improvement. The author first discusses to which extent and how it is better to improve energy efficiency rather than let increase investments in energy production and distribution, emissions and energy imports. He therefore discusses the various types of measures: information, incentive and financial, economic, regulatory, or others. In the second part, he discusses how to assess the results of energy efficiency policies, and more particularly at the level of global economy and of main sectors by using various indicators like energetic intensity, final energetic intensity at constant structure, or technical-economic indicators