Evaluation of synchronous execution of full repowering and solar assisting in a 200 MW steam power plant, a case study

Abstract This study investigates a full repowering simultaneously with merging solar energy in 200 MW units of Montazeri Steam Power Plant in Iran. A 400 MW gas turbine has been used for full repowering. A part of feed water in the solar field turns into saturated steam. In the repowered cycle without the involvement of solar energy, the energy and exergy efficiencies have increased by 76.8% and 73% reaching to 59.11% and 56.63%, respectively. In power increase mode, the mass flow rate of water in solar field is not to be more than 31.3 kg/s. Under this condition, the power of the steam turbines will experience a 16.8 MW increase. In efficiency improvement mode, with 75 kg/s feed water in solar field and the generation power of the steam turbine to be fixed, the consumption of natural gas by the gas turbine will decrease 2.21 kg/s. This will reduce natural gas consumption and CO 2 emissions by 21,481,200 kg and 43,392 ton per year, respectively. Considering the price of natural gas and CO 2 to be 0.2 USD/kg and 100 USD/ton respectively, the rewarded profit due to a reduction in both fuel consumption and CO 2 emission will be 8,635,440 USD per year.