Green Productivity in Iran's Thermal Power Plants: The Malmquist-Luenberger Approach

Electricity generation in thermal power plants as the largest producer of electricity in Iran is associated with greenhouse gas emissions. In this paper, using the Malmquist-Luenberger method, green productivity, and efficiency changes are measured for 31 thermal power plants (including 12 steam power plants, 13 gas power plants, and six combined cycle power plants) during 2009-2016. The results show a slight increase in green productivity in gas power plants and a slight reduction in green productivity in combined cycle power plants. Also, green productivity in steam power plants has not changed approximately. The mean values of the Malmquist-Luenberger index for these three types of power plants are 1.007, 0.997, and 1.0005, respectively. Although the environmental performance of gas power plants is slightly better than the two other types of power plants, but the difference of mean values of the Malmquist-Luenberger index for the three types of power plants is small.Furthermore, if we compare the power plants individually, we get different results, the highest and lowest mean values of the Malmquist-Luenberger index (1.06 and 0.982) is for a steam power plant (Shahid Mofateh) and a gas power plant (Konarak) respectively. Therefore, the power generation method and type of power plant (gas, steam and combined cycle) have no significant effect on the environmental performance of power plants and the environmental performance of them can be affected by other factors. The results also show that combined cycle power plants are more efficient than gas power plants.