Techno-economic selection and initial evaluation of supercritical CO2 cycles for particle technology-based concentrating solar power plants

In this study, the techno-economic performance of supercritical carbon dioxide (sCO2) power cycles in concentrating solar power plants based on particle technology is assessed. A simplified levelized cost of electricity calculation was used to investigate the effect of cycle parameters, compare cycle layouts and allow for comparing optimized sCO2 power blocks with steam technology. Results showed that simple cycle layouts with fewer components and lower cycle parameters lead to the lowest energy cost. This is caused by (a) fewer components, (b) lower primary heat exchanger, turbine as well as recuperator cost if the turbine inlet temperatures is limited and (c) a lower cost of the thermal storage system if the sCO2 temperature increase in the primary heat exchanger is large. Nevertheless, even the most economical sCO2 variants generate electricity at a 10 % higher cost than a steam reference system and a significantly lower efficiency. These results held true when changes were made to cost models. Finally, it was shown that the cost of main sCO2 equipment would have to be reduced by 30 %–50 % to reach cost parity with steam systems. These findings will need to be confirmed with more detailed off-design simulations and optimized solar field components.