Thermodynamic design of the novel energy storage system based on liquid carbon dioxide for a 17 MW concentrated solar thermal power plant

Abstract

Currently, the majority of electric power generation in Iran is provided through fossil fuel power plants. Recently, the effort to increase the share of renewable energy in the energy supply portfolio is increasing. Naturally, none of the renewable energy plants in this country are currently equipped with an energy storage system. The first concentrated solar thermal power plant of this country is currently under construction with a nominal capacity of 17 MW, but it has not yet been put into operation. Therefore, in this research, the thermodynamic design of the energy storage system based on liquid carbon dioxide is presented to be coupled with it. The results of the research showed that the energy generated per unit of storage volume of the designed system is equal to 17.6 kWh and the thermal, exergy and round-trip efficiencies of the system are equal to 36.14 %, 61.51 % and 40.63 %, respectively. Also, the effect of turbine and pump efficiencies on the output of the designed energy storage system was investigated and it was shown that with the increase in turbine efficiency, the effectiveness of the system enhances; while increasing the pump efficiency does not have much effect on the performance of the system.