Techno-Economics of Cogeneration Approaches for Combined Power and Desalination From Concentrated Solar Power

Abstract

For many decades, integration of concentrated solar power (CSP) and desalination relied solely on the use of conventional steam Rankine cycles with thermally based desalination technologies. However, CSP research focus is shifting toward the use of supercritical CO2 Brayton cycles due to the significant improvement in thermal efficiencies. Here, we present a techno-economic study that compares the generated power and freshwater produced from a CSP system operated with a Rankine and Brayton cycle. Such a study facilitates co-analysis of the costs of producing both electricity and water among the other trade-off assessments. To minimize the levelized cost of water (LCOW), a desalination facility utilizing multi-effect distillation with thermal vapor compression (MED/TVC) instead of multistage flash distillation (MSF) is most suitable. The techno-economic analysis reveals that in areas where water production is crucial to be optimized, although levelized cost of electricity (LCOE) values are lowest for wet-cooled recompression closed Brayton cycle (RCBR) with MSF (12.1 cents/kWhe) and MED/TVC (12.4 cents/kWhe), there is only a 0.35 cents/kWhe increase for dry-cooled RCBR with MED/TVC to a cost of 12.8 cents/kWhe. This suggests that the best candidate for optimizing water production while minimizing both LCOW and LCOE is dry-cooled RCBR with MED/TVC desalination.