Investigation of a renewable energy-based integrated system for baseload power generation

Abstract

A renewable energy-based integrated system is proposed for baseload power generation. Wind, solar, and biomass options are considered. The electric power produced by wind turbines, a photovoltaic (PV) system, and fuel cells is fed to the power grid. The surplus electricity produced by the integrated energy system is stored in forms of compressed air and hydrogen. When required, the compressed air is heated in a combustion process and expanded in a gas turbine for further power generation. The hydrogen produced by the electrolysis process is fed to a solid oxide fuel cell (SOFC) system for electricity generation. The system is analyzed with energy and exergy methods, and results are presented for monthly power generation, compressed air energy storage (CAES) and compression, and hydrogen production and consumption rates. Moreover, exergoeconomic analyses are performed based on the unit exergy cost of the electricity produced by the integrated system. The round-trip efficiency of the CAES system is 60 % without considering heat recovery potentials. The overall energy and exergy efficiencies of the integrated system are 37.0 and 31.9 %, respectively. Results of the exergoeconomic analyses show that the unit cost of electricity generated by the Wind-CAES system is 7 ¢/kWh, while it is 89 and 17 ¢/kWh for the photovoltaic-hydrogen-solid oxide fuel cell and the biomass-solid oxide fuel cell-gas turbine systems, respectively.