On May 21st, the Department of Energy SunShot Initiative announced $10M for six new R&D projects that will advance innovative concentrating solar power (CSP) technologies. The Concentrating Solar Power: Efficiently Leveraging Equilibrium Mechanisms for Engineering New Thermochemical Storage (CSP:ELEMENTS) funding program supports developing thermochemical energy storage (TCES) systems that can validate a cost of ≤ $15/kWh_th and operate at temperatures ≥ 650 °C (> 1200 °F).

TCES presents opportunities for storing the sun’s energy at high densities in the form of chemical bonds (thus using less storage material) for use in utility-scale CSP electricity generation. “By improving energy storage technologies for concentrating solar power systems, we can enhance our ability to provide clean and reliable solar power, even when the sun is not shining,” said Energy Secretary Ernest Moniz.

One of the six SunShot Initiative R&D projects, The Sandia-led CSP:ELEMENTS-funded project, “PROMOTES” ([High] Performance Reduction/Oxidation Metal Oxides for Thermochemical Energy Storage), proposes a system that concentrates sunlight onto a falling curtain of particles called perovskites. These perovskites utilize the heat to undergo a reaction which “stores” the concentrated solar thermal energy in chemical bonds. The perovskites are then stored until the heat is required. Exposing the perovskites to air reverses the chemical reaction, releasing the stored solar heat energy for use in a very efficient air-Brayton electric power generation system.

The PROMOTES research team members and key participants include:

• Sandia National Laboratories: Drs. James Miller, Andrea Ambrosini, and Clifford Ho.
• Georgia Institute of Technology: Profs. Peter Loutzenhiser and Sheldon Jeter.
• King Saud University: Prof. Hany Al-Ansary. 
• Arizona State University: Prof. Ellen Stechel.

The Sandia-led PROMOTES project will leverage Sandia’s deep experience and knowledge base in metal-oxide thermochemistry and solar particle receivers/reactor work currently funded by the DOE SunShot Initiative to methodically design, develop, characterize, and demonstrate a robust and innovative storage cycle based on newly developed redox-active metal oxides. Sandia and collaborators will develop, characterize, and demonstrate a first-of-its-kind 100 kW_th particle-based TCES system for direct integration with combined-cycle Air Brayton power generator based on the endothermic reduction and exothermic reoxidation of our developed metal-oxide materials.