Thermo-economic evaluation of water-injected air bottoming cycles hybridization using heliostat field collector: Comparative analyses

Abstract

A possible solution to intermittency and storage difficulties associated with solar energy utilization is power plant hybridization. Additionally, air bottoming cycle is an alternative plant configuration which is more economical for small scale power generation than conventional combined cycle. To further improve the air bottoming cycle thermo-economic performance, water injection in the bottoming cycle air is proposed. In this paper, a detailed thermo-economic optimization is conducted for a hybrid air bottoming cycle power plant with water injection in the bottoming cycle air. Analyses are accomplished by utilizing three thermo-economic assessment approaches comprising levelized cost of electricity, payback period and life cycle savings. The acquired results indicate the advantages of water injection to improve the bottoming cycle heat recovery capability and plant's levelized cost of electricity. Noting that the plant's levelized cost of electricity is improved by 0.7 US$/MWh from 77.8 US$/MWh to 77.1 US$/MWh as water injection in the bottoming cycle is implemented. Therefore, 2.940 MUS$ can be saved during 25 years of plant operation.