For a 50 MWe direct steam generation(DSG)solar power tower plant with dual-receiver

the influences of solar multiple and thermal storage hour on its performance and levelized cost of electric energy(LCOE) were analyzed by establishing the tower power plant system coupling model and the economic evaluation model. The results show that

at design point

when the solar multiple varies from 1.0 to 3.0

the heliostat field efficiency reduces from 67.8% to 62.3% with the increasing solar multiple

while thermal efficiency of the dual-receiver varies little with the varying solar multiple and the Rankine cycle efficiency remains 40.6% for different solar multiples. For annual evaluation factors

both the annual electricity production and annual capacity factor increase with the solar multiple and the thermal storage hour. The optimization results show that the minimum LCOE is 0. 214 $/(k W·h) when the solar multiple is 2.7 and the thermal storage capacity is 9 h. The corresponding annual capacity factor is 0.501 and the annual electricity production is 219.5 GW·h. Monthly performance of the plant is achieved with the lowest LCOE and shows that high direct normal irradiation(DNI) is beneficial for high capacity factor and high electricity production.