The need to achieve high efficiency in the country's electricity industry is vital due to limited resources, increasing demand for electricity, strong dependence of other industries on this industry and environmental issues. Considering that thermal power plants play a key role in the country's electricity supply by using fossil fuels, the purpose of this study is to compare the technical and environmental efficiency of selected thermal power plants in the country during the years 1389-1397. In this study, non-parametric practical method and data envelopment analysis method with output-oriented approach are used. It was 71.9% and 87.8%. The study of the average bio-efficiency of these power plants during this period shows that this efficiency has been between 71 and 83.8%. During the period under review, Rey power plant has always had the lowest technical and bio-efficiency. The inefficiency of this power plant has been due to managerial and scale inefficiencies both. The results show that technical efficiency in 1390 and bio-efficiency in 1395 have decreased simultaneously for various reasons such as managerial inefficiency or scale inefficiency or both. The amount of carbon dioxide emissions in 1392 was higher than other years under review, which was due to the reduction of natural gas consumption. Also, the amount of sulfur dioxide emissions during the years 1390-92 due to high consumption of fuel oil and gas oil was more than other years that this method of fuel consumption has reduced the bio-efficiency of power plants in 1392. The same results confirm that based on the three defined scenarios, the coded prices in different scenarios are estimated at 982, 827 and 780 Rials, respectively. Based on the results, it can be said that pricing based on final cost has left the industry with a deficit. In other words, in terms of the final cost pricing method, sufficient return is not provided, and based on this, cryptographic pricing can be a pricing method Be the background.