To help propel new forms of renewable energy, the Department of Energy’s Solar Energy Technologies Office has been encouraging development of next generation concentrating solar power (CSP) systems. CSP systems offer a distinct advantage over photovoltaics by enabling energy storage through means other than batteries. CSP uses a field of mirrors (heliostats) to concentrate sunlight onto a target (receiver) to irradiate a heat transfer medium. That heated medium is then used to generate electricity or drive other thermochemical reactions. Researchers at Sandia are investigating using particles (specifically, a ceramic bauxite particle) inside the receiver within a gravity-driven, tower system ...