Thermo-economic analysis of a particle-based multi-tower solar power plant using unfired combined cycle for evening peak power generation

Abstract This work analyses a 150 MWe multi-tower solar-only combined cycle power plant (nominal efficiency ∼50%) for evening peak operation. Olivine particles are used as heat transfer fluid and thermal energy storage medium based on their suitable thermo-physical properties for high temperature operation. Technical constraints to handle hot particles lead to an integration of the power block and thermal storage system with an array of heliostat fields (with a solar receiver per field). Unitary 53.0 MWth solar tower was designed to satisfy these constrains. Two electricity dispatch strategies covering the evening peak power have been analyzed. Number of solar fields and storage capacity have been optimized from thermo-economic optimization. It is concluded that the best layouts have seven solar towers and storage capacities of 2.0 GWh for the first dispatch scenario (with an electricity generation from 17:00 to 22:00) and eight solar towers with 2.5 GWh for the second one (from 17:00 to 24:00). Solar multiple is between 1.1 and 1.25. These two configurations cover 56.2% and 55.8% of the total energy demand at full power with LCOE of 14.6 c€ kWh−1 and 13.2 c€ kWh−1. A sensitivity analysis on the components costs indicates that 11.0 c€ kWh−1 could be achieved.