Re-Designing the CSP Thermal Energy Storage System to Enable Higher-Temperature Performance at Reduced Cost: Final Technical Report

Youyang Zhao, Ryan Bowers

Research output: NRELTechnical Report

Abstract

Current commercial concentrating solar power (CSP) plants distinguish themselves from ordinary photovoltaic (PV) power plants by storing enough collected energy to enable generation for several hours after the sun goes down. CSP plants store this energy in the sensible heat of nitrate salts in large metallic storage tanks. Stainless-steel AISI 347H (SS347H) is needed for the hot tank operating at about 565 degrees C whereas carbon steel is sufficient for the cold-tank materials. Two-tank nitrate-salt thermal energy storage (TES) is presently in use in several trough-based CSP plants in Europe and in the U.S., operating up to about 390 degrees C. Three commercially operating tower-based CSP plants - Gemasolar in Spain, Crescent Dunes in Nevada, and Noor III in Morocco - use the same approach, storing nitrate salts at temperatures up to 580 degrees C. SS347H is many times more expensive than carbon steel and constitutes a significant cost element in today's CSP plants. Hence, CSP developers need to close the cost gap with PV-based solar plants by making cost reductions in every system of the plant. Redesigning the TES tanks is one opportunity for cost reduction.
Original languageAmerican English
Number of pages73
DOIs
StatePublished - 2023

NREL Publication Number

  • NREL/TP-5700-84409

Keywords

  • cenosphere
  • molten nitrate
  • thermal energy storage
  • thermal insulation

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