A schematic of the proposed reactor system. The metal oxides (MOs)  absorb/capture concentrated solar energy in . Because the energy is captured in chemical bonds, it can be stored for long periods  and released at need  for electricity generation . MOs are particularly suitable for the Air Brayton power cycle because of their high temperature range and the use of pressurized air, in which the air is both the reactant for the reoxidation step and the heat-transfer-fluid input directly into the Brayton-cycle turbine.
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.
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.
Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-AC04-94AL85000.