To Make Solar Really Work, Turn Up the Heat
It’s the National Solar Thermal
The hundreds of mirrors focus sunlight onto a receiver at the top of the solar tower. In conventional systems, this would heat water or other fluids to generate steam that drives an electric turbine. But here a curtain of fine ceramic particles continually falls through the concentrated sunbeam instead. The particles, which resemble black sand, can easily reach temperatures 100 ˚C hotter than those standard fluids. That promises to boost the available energy, cutting the costs of production and storage.
This approach is one of three that federal researchers believe could help concentrating solar power finally become affordable and sustainable. Last January, the National Renewable Energy Laboratory published a next-generation demonstration road map that highlighted falling particles, higher-temperature molten-salt systems, and a gas-based heat transfer fluid as promising pathways to produce solar thermal energy at six cents per kilowatt-hour by 2020, a goal set by the Department of Energy’s SunShot Initiative in 2011.
