Assessment of Thermal Energy Storage for Parabolic Trough Solar Power Plants

Parabolic trough power plant technology is one of the most demonstrated solar power options commercially available. While trough power plants are the least expensive solar option, cost of electricity still exceeds that needed to directly compete with conventional fossil-fired large-scale central power technologies. Several evaluations have been done that identify a series of mechanisms for significant cost reduction over the next decade. One of the opportunities for improving the economics of parabolic trough plants is the development of lower cost and more efficient thermal energy storage (TES) technologies. This paper focuses on several of the TES technologies currently under development, namely: the use of an indirect molten-salt storage system, the use of molten-salt as a heat transfer fluid in the solar field and thermal energy storage system, and the development of new types of storage fluids. The assessment compares the cost and performance of these candidate thermal energy storage technologies by evaluating their impact on the levelized cost of electricity from the plant. This analysis is updated based on work conducted on these technologies during the last year.