According to the Ministry of Energy, thermal power plants account for 80.8 percent share of total power plants in the country.

The total production capacity of power plants in the world stands at 6,628 gigawatts and thermal power plants have a 61 percent share with the production capacity of 4,017 gigawatts.

Among non-thermal power plants, about 14.8 percent of total nominal capacity of power plants of the country is related to the hydroelectricity power plants, 0.9 percent to the renewable units, 1.3 percent to nuclear power plants, 0.5 percent to the diesel-powered units while the rest 1.8 percent is related to the small-scale gas units.

In Iran, gas-, steam- and combined cycle power plants with the production capacity more than 25 megawatts are known as mega thermal power plant.

In thermal power plants, thermal energy in the initial fuel is turned into electrical energy.