Design and performance analysis of a solar-geothermal-hydrogen production hybrid generation based on S–CO2 driven and waste-heat cascade utilization

In the present paper, a multi-energy complementary power generation is designed. It's a hybrid plant of solar power, geothermal power and hydrogen power based on S–CO2 and T-CO2 brayton cycle driven. The thermal power for hydrogen production is gained from the extracting S–CO2 of solar power side and power consumption is 0.2% of PEM. The hybrid plant has the novel feature of time and energy complementarity. Through the thermodynamic analysis, the results reveal that energy efficiency and exergy efficiency could reach 78.14% and 84.04%, comparing with some other hybrid plans, the values have increased by about 20% and 30%, respectively. Through a sensitivity analysis, three optimal split radios have been put forward and the values are 0.68, 0.93 and 0.96, respectively. The Mg–Cl thermochemical cycle is used to hydrogen production and producing hydrogen energy is about 0.902 GJ/h. The economic analysis is investigated by COES and CRF, and the net economic profit is at least 42.11 million USD. The proposal system is based on the S–CO2 and T-CO2 driven and the daily average CO2 circulating flow could get 55.0 × 106 kg, it could decrease lots of greenhouse-gas emissions.