Today (Nov. 3) Oregon State University (OSU) announced that its engineers have identified a new way to store the energy produced by the sun. The engineers involved in the project said that the approach can help reduce the cost of energy storage and make it more practical for wider use.
Concentrated solar power (CSP), particularly solar thermal, has an advantage over photovoltaics, or solar panels, its energy can be stored more directly by capturing it in a medium like molten salt or oils. By capturing it in a medium the solar energy can also be used on an as needed basis like energy produced by a natural gas or nuclear power plant. But lately these types of projects, all of which are quite large, have stalled in the U.S. The new innovation from OSU may help renew more innovation in solar thermal.
The new OSU innovation stores thermal energy in strontium carbonate—it works by decomposing the carbonate into strontium oxide and carbon dioxide, which consumes thermal energy. When strontium oxide and carbon dioxide are combined into strontium carbonate it releases stored heat.
"In these types of systems, energy efficiency is closely related to use of the highest temperatures possible,” said Nick AuYeung, an assistant professor of chemical engineering in the OSU College of Engineering and corresponding author on this study. "The molten salts now being used to store solar thermal energy can only work at about 600 degrees centigrade, and also require large containers and corrosive materials. The compound we're studying can be used at up to 1,200 degrees, and might be twice as efficient as existing systems.”
"With the compounds we're studying, there's significant potential to lower costs and increase efficiency," Ahyueng said. The molten salts also are more corrosive than the strontium carbonate. These materials are nonflammable, readily available and environmentally safe, OSU stated. As such, the amounts of materials needed to store energy could be reduced, as could the size of container units, both of which would help reduce costs.
In this model the thermochemical storage is used to hold heat. Whereas in a battery the medium stores electricity. Like a battery the energy is stored in chemical bonds, not thermally. So theoretically the energy could be stored for years and discharged when needed. The team published its research in ChemSusChem and was supported by the SunShot Initiative of the U.S. Department of Energy.Tweet