During the past two decades, environmental side effects of economic activities have become the central part of public and political discussions. An effective energy policy should encourage the different enterprises, utility companies and individuals to utilize energy efficiently and in more environmental friendly processes, technologies, and materials. Fossil fuels are responsible for the large amount of human-related air pollution. Among the fossil fuels, natural gas plays the most important role in Iran's fuel-fired generating system and is the preferred fuel due to its cleaner combustion characteristics compared to other fuels.The study provides a comprehensive efficiency analysis of specific applications of steam power plants in Iran to serve the applied strategy to the component stakeholders for doing policy implication.Furthermore, it would be mostly valuable to indicate what changes would be necessary to increase the efficiency of the most inefficient plants to the level of their efficient peers.