Pacific Northwest National Laboratory researchers will develop a system to use solar heat after the sun goes down with a $2.9 million grant awarded last week.
The grant was among $10 million awarded by the Department of Energy to advance research on concentrating solar power with thermochemical storage systems. DOE's SunShot Initiative is working to develop concentrating solar power technologies and make solar energy cost competitive with traditional forms of electricity by the end of the decade.
"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.
Thermal energy storage has been limited because the molten salts usually used to store solar heat for power production require large, expensive equipment, according to PNNL.
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But PNNL materials scientist Ewa Ronnebro and her team have developed proprietary powders of metal bonded to hydrogen that can store more heat than molten salts. Ronnebro's method provides a smaller and more efficient system, according to PNNL.
The new system uses two metal hydride powders to store solar heat and later release it. Then steam warmed with the stored solar heat can be run through turbines in a power plant to generate electricity.
PNNL previously refined one of the powders, which operates at high temperatures to capture the sun's heat, and now Ronnebro and her team will work to improve the other powder, which works near room temperatures to store the hydrogen gas released by the heat capture process.
The pairing of the high and low temperature hydride beds enable hydrogen gas storage at low pressures, reducing costs to a level that current gas storage methods cannot match, according to DOE.
During the three-year project, PNNL and commercial research partners will build and test a large-scale thermal energy storage system. The demonstration system is planned to generate up to 240 kilowatt-hours of energy, or a little more than a quarter of the energy that a typical American home consumes each month.
Research partners are ADMA Products of Hudson, Ohio; Butler Sun Solutions of Solana Beach, Calif., and Diver Solar of Albuquerque, N.M. A cost share of $742,000 with the grant money is required.