Dive Brief:
- Researchers at Oregon State University and the University of Florida have come up with a new storage technology could enable wider use of concentrated solar power as a distributed resource, Gizmag reports.
- Using a thermochemical reaction, the researchers claim to be able to gain a tenfold increase in energy storage density at a fraction of the cost of alternative technologies.
- The process uses the heat collected from a solar collection system to break down strontium carbonate into strontium oxide and carbon dioxide. When the two chemicals are recombined, they release heat that can be used to power a turbine.
Dive Insight:
The long-standing problem with solar power is that it doesn’t work when the sun goes down, which is when most people turn on their lights.
But in a new report researchers at Oregon State University and the University of Florida say they have devised a new type of thermochemical reaction that could efficiently and significantly extend the storage capabilities of a concentrated solar power (CSP) plant.
A CSP plant uses an array of mirrors to concentrate the heat of the sun on a liquid that, when heated, can power a conventional turbine-generator set.
There are currently 1,400 MW of CSP plants in the United States with another 390 MW expected to be brought online this year, but only about 250 MW of that total includes storage. To date the usual approach with CSP storage has been to use molten salt to store and release heat. The process works, but can be expensive.
The researchers from Oregon State and the University of Florida, supported by funding from the Department of Energy’s SunShot Initiative, have come up with another means of storing energy.
Their system relies on the reversible decomposition of strontium carbonate into strontium oxide and carbon dioxide by subjecting it to solar heat. When those components are recombined during discharge of the system, they release the stored heat.
The researchers say their system has advantages over molten salt CSP storage. The molten salt systems in use work only at about 600 degrees centigrade, require large containers and involve corrosive materials. They say their strontium system can be used at up to 1,200 degrees centigrade 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,” said Nick AuYeung, an assistant professor of chemical engineering in the OSU College of Engineering.
The researchers’ materials are also nonflammable, which could be an advantage in light of recent news regarding fires at Abengoa’s Solana CSP+storage facility in Arizona.
But the new thermochemical storage technology still has its own issues to resolve. The researchers say the energy storage capacity of the process declined after 45 heating and cooling cycles, due to some changes in the underlying materials. Further research will be needed to identify ways to reprocess the materials or significantly extend the number of cycles that could be performed before any reprocessing was needed, AuYeung said.