U.S. Department of Energy - Energy Efficiency and Renewable Energy

SunShot Initiative

Thermochemical Heat Storage for CSP Based on Multivalent Metal Oxides

General Atomics logo Chart with a red line, representing re-oxidation, and a blue line, representing reduction, with time on the x-axis and temperature on the y-axis.

Fast redox was achieved via mixed metal oxides and the application of a rotary-kiln (moving-bed) reactor.

General Atomics (GA), under the Thermal Storage FOA, is developing a high-density thermochemical heat storage system based on solid metal oxides.


Metal oxides that are capable of both thermal reduction and oxidation (redox) in air were identified via experimental measurements. GA set up preliminary process flowsheets to estimate the levelized cost of energy and storage cost associated with the identified oxides. Oxides with the best economic potential were selected for further process development.

GA studied the means to improve oxide redox kinetics and stability. Modeling was carried out to a) characterize the packed-bed behavior and b) establish a reactor design that provide the best system economics. GA also assessed other novel moving-bed reactor designs.


Solar energy is stored chemically in reduced solid oxides. Heat is released at a constant temperature. Air is used as both the heat-transfer fluid and the chemical reactants. Oxide systems can be tailored to match input heat temperature.

Publications, Patents, and Awards

  • B. Wong, L. Brown, F. Schaube, R. Tamme, and C. Sattler, "Oxide Based Thermochemical Heat Storage," in Proceedings of 16th Annual Solar PACES Conference, Perpignan, France, September 21-24, 2010.
  • R. Buckingham, B. Wong, L. Brown, C. Sattler, F. Schaube, and A. Woerner, "Metal Oxide Based Thermochemical Energy Storage for Concentrated Solar Power – Thermodynamics and Parasitic Loads for Packed Bed Reactors," in Proceedings of 17th Annual Solar PACES Conference, Granada, Spain, September 20-23, 2011.
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Learn about other DOE competitive awards for concentrating solar power research that are in progress.