Impact of process temperature on the cost of concentrating solar thermal industrial process heat

Concentrating solar thermal (CST) power towers can provide high flux concentrations at commercial scale. As a result, CST towers exhibit potential for high-temperature solar industrial process heat (SIPH) applications. However, at higher operating temperatures, thermal radiation losses can be significant. This study explores the trade-off between thermal and optical losses for SIPH applications using a collection of three case studies at operating temperatures that range from 900-1,550 °C, comparing levelized costs estimates to a baseline estimate of levelized cost of heat (LCOH) for a molten-salt tower system. System costs are restricted to the tower, receiver, and solar field so that the analysis is agnostic to the end use. Blackbody radiation composes the thermal losses at the receiver and ray tracing software estimates the optical losses. The results show the impact of process temperature on the maximum attainable system efficiency, as well as the higher flux concentration requirements as the temperature increases. Under current cost assumptions, the optimal solar field size is larger when optimizing the system design to minimize LCOH compared to maximizing efficiency. The results of this study illustrate the importance of considering the temperature of an industrial process when determining levelized cost goals when using CST technologies to produce process heat at high temperatures. • We analyze concentrating solar thermal applications to industrial process heat. • We compare levelized cost of heat at three temperatures to a molten-salt baseline. • We explore the trade-offs between optical losses, thermal losses, and system costs. • We show the sensitivity of the receiver concentration ratio to levelized costs. • We propose that goals for levelized cost of heat be temperature-specific.