A combined cycle power plant uses a gas as well as an auxiliary steam turbine to improve its overall efficiency, with the former being the primary power generator and the latter recovering the exhaust gas heat. Individually, gas turbine and steam turbine power plants have an average efficiency between 25 % and 40 %, depending on their fuel source and capacity. However, when installed in combination, it increases to 60%. In terms of capacity, fuel, and number of turbines, the combined cycle power plant can have several configurations such as: 1×1 (one gas turbine, one steam turbine), 2×1 (two gas turbines, one steam turbine), 3×1 (three gas turbines, one steam turbine), and sometimes even 4×1 (four gas turbines, one steam turbine).