Demonstration of 3.5 MWth Parabolic Trough With Ternary Molten Salt at the Évora Molten Salt Platform

Commercial solar thermal parabolic trough power plants use thermal oil as a heat transfer medium in the solar field. Within the framework of the “High Performance Solar 2” (HPS2) research project a molten salt parabolic trough demonstration plant was commissioned in summer 2021 in Évora, Portugal. Since then it has been operated for more than 5.500 h between 180°C and 500 °C, jointly by the University of Évora, DLR and TSK Flagsol. This article presents the main steps of cold and hot commissioning as well as experiences gained in plant operation. It has been shown that filling a preheated solar field with ternary molten salt is not critical, but its drainage can be challenging depending on the quality of the heat tracing and the solar field slope.