A review on analyzing and evaluating the energy utilization efficiency of countries

In recent years, there has been an increasing interest in applying energy and exergy analysis modeling techniques for energy-utilization assessments in order to attain energy saving. In this regard, various approaches have been used to perform the exergy analyses of countries. The main objective of the present study is to evaluate and analyze the energy utilization efficiencies of countries by reviewing the studies conducted on various countries or societies, to which different approaches have been applied. Thermodynamic relations used to perform energy and exergy analyses of countries are given first. The classification of studies conducted and the approaches applied are then investigated in terms of subsectors, such as utility, industrial, residential–commercial, and transportation sectors. Next, the countries considered are evaluated in terms of energy and exergy utilization efficiencies. Finally, the results obtained are discussed. It is expected that the review presented here will provide the investigators with knowledge about how much effective and efficient a country uses its natural resources. This knowledge is also needed for identifying energy efficiency and/or energy conservation opportunities as well as for dictating the energy strategies of a country or a society.