Compared with the conventional steam Rankine cycle

the supercritical carbon dioxide(S-CO_2) Brayton cycle can achieve higher power generation efficiency when used in concentrated solar power(CSP) system. This paper formulates a mathematical model for the CSP-S-CO_2 Brayton cycle system. The objective is to minimize levelized cost of electricity(LCOE) of the CSP-S-CO_2 Brayton cycle system by optimizing the parameters of the integrated system by equation-based method. Sensitivity analysis is carried out to investigate the impact of key parameters of the cycle. Moreover

the model is applied to optimization design of a 50 MW-level CSP-S-CO_2 power station

and the results show that

the CSP-S-CO_2 power plant achieves a minimum LCOE of 0.817 yuan/(kW·h) with the heat storage capacity of 8 h

turbine inlet temperature of 520.85 ℃

turbine inlet pressure of 25 MPa and compressor inlet pressure of 8.63 MPa. The LCOE is 17.81% lower than that of the conventional CSP-steam Rankine cycle power plant(0.994 yuan/(kW·h)). Furthermore

case studies show that

a larger thermal storage capacity results in a lower LCOE. On the other hand

the system achieves the minimum LCOE with a moderate turbine inlet temperature

split ratio and pressure ratio. Finally

improving the isentropic efficiency of the turbine and compressor can reduce the LCOE of the system significantly.