UCLA Team Leads Solar Molten Metal Effort

Liquid metal may offer a way to make solar power plants far more efficient. | Photo: P. Gordon/Flickr/Creative Commons License

Concentrating thermal solar power has taken a serious beating in the last few years. The technology, in which mirrors or lenses concentrate the sun's rays to generate heat, is having more and more trouble competing against plain old room-temperature photovoltaic (PV) panels, whose price has dropped dramatically.

But with support from the Department of Energy's SunShot Initiative, a group of researchers led by a UCLA team is looking into ways of giving concentrating solar thermal a new lease on life -- using molten metals.

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Concentrating solar power (CSP) could theoretically win out over PV in the long run, at least in some applications, because the technology offers the possibility of turning sunlight into electrical power at very high efficiencies. Current designs focus sunlight to heat up a so-called "heat transfer fluid," which is then piped to a turbine building where it either runs the turbine directly, or heats another fluid to do so in a heat exchanger. Problem is, in order to reach those efficiences -- as much as 50%, the engineers say -- concentrating solar facilities will need to be able to get those heat-transfer fluids hotter than 1,200°F. Right now, the best we can get is about 1,050°F.

The Energy Department's "SunShot Initiative" -- modeled on the Kennedy-era moon shot initiative -- has granted $5 million for a five-year program to investigate using molten metals as heat transfer fluids in solar thermal systems. The molten metals team will be led by researchers from UCLA, and includes engineers from UC Berkeley and Yale.

UCLA declined to identify the university staff involved as contracts for the grant have not yet been signed, but confirmed to ReWire that the person heading up the project is a researcher in UCLA's Engineering Department.

Along with the molten metals project, the SunShot Initiative also granted $5 million for a five year study by University of Arizona and Georgia Tech researchers looking into ways to increase working temperatures in systems that use molten salt as a heat transfer fluid.

By increasing concentrating solar thermal's efficiency, the researchers could bring the cost of power from such facilities closer to their PV competition's cost per kilowatt-hour. Greater efficiency would also allow siting facilities in areas with less-powerful sunlight, which might offer the prospect of smaller facilities in coastal areas or other cloudy locations, giving our beleaguered desert wildlands a break.

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