Enhancing solar power plant efficiency with compressed air energy storage: A comprehensive exergoeconomic and environmental evaluation

Addressing power demand during peak periods is a critical responsibility in energy management. Compressed air energy storage is an effective solution for this objective. The present study proposes a solar power unit with compressed air energy storage, in which the solar power plant provides input power to the storage system during off-peak hours. The solar facility incorporates a supercritical carbon dioxide unit and an organic Rankine cycle. To enhance performance, two organic Rankine cycles are employed to utilize the waste heat from the carbon dioxide cycle and compressed air. Furthermore, all working fluids in Rankine cycles are zeotropic mixtures. Thermodynamic, economic, and exergoenvironmental studies are conducted to evaluate integration performance, which is included in the triple-objective optimization method. Elevating the supercritical carbon dioxide turbine's inlet pressure from 14 to 18.82 MPa enhances net power and exergetic efficiency, though these metrics decline at higher pressures. Increasing charging pressure enhances the exergetic round-trip efficiency. The optimal values for integration's capital investment and net present value are $61.09 M and $96.77 M, respectively, achieved at a 2028 $/h product cost rate. The product's exergoenvironmental impact is approximately 283.34 Pt/h.