Abstract
The design and the performance of a medium-scale modular solar power plant (similar to 20 MW) integrating a gas turbine combined cycle with a fluidized particle-in-tube receiver and direct thermal storage are investigated in this paper. A practical technique is used to design each part of the solar power plant. The complete design starts with the solar gas turbine (SGT) since it defines the necessary power to run it; then, the other parts are designed upstream. Three different cases are investigated under different operation strategies corresponding to two particle temperatures 750 degrees C and 880 degrees C, and hybrid and solar-only operation modes respectively. The results show that the nominal efficiency of the components including the heliostat field, the solar receiver, the gas turbine, and the steam turbine can reach 67%, 80%, 32%, and 34.5% respectively. As a result, the nominal thermal efficiency and the annual capacity factor of the complete solar power plant achieve 46% and 33.47% respectively. The overall nominal efficiency (solar-to-electric efficiency) of the plant for hybrid operation mode is 25.80%. It varies from 21.16% to 24.7% for the solar-only operation mode. Special interest is shown to the part-load operations.