Impact of Solar Tower Design Parameters on xCO2-based Solar Tower Plants

Abstract

Integrating high efficiency sCO2 power cycles into solar tower plants is characterized by high upper temperature and low temperature spread of the cycle working fluid sCO2. New heat transfer media (HTM) are required, enabling higher temperatures and low cost storage. The present study evaluates modular solar tower plants using solid particles as HTM, allowing temperatures up to 1000°C. In a parameter study the influence of HTM temperatures on levelized cost of electricity (LCoE) is evaluated. The results show a significant impact of the HTM temperature selection, mainly governed by the HTM temperature difference. A high temperature difference results in reduced LCoE. The most important factors for this reduction are the reductions in particle inventory, storage containment, and particle-sCO2 heat exchanger. This reduction is partially offset by an increase in heliostat field and tower cost. The results indicate that the use of solid particles for solar high efficiency sCO2 power cycles offers unique advantages due to the wide temperature range of the particles.