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Researcher explores solar energy storage


Florida may be nicknamed the “Sunshine State,” but one USF professor thinks it has been lagging behind in efficient use of solar energy.

For Floridians, the problem with utilizing solar energy is that, for the most part, the weather is unpredictable and there is currently no efficient way to store solar energy.

Yogi Goswami, a professor in the College of Engineering, recently developed a method that he said can make storing electricity from solar energy more useable and cost-effective.

Goswami said the storage of solar energy needs to be perfected in order to yield low-cost solar energy.

“Solar energy is intermittent, so for it to become a significant portion of energy used, it needs to be stored with efficiency,” he said.

One way of ensuring cheaper storage, Goswami said, is through the use of cheaper materials.

“We chose salt as the material to use,” Goswami said. “It is a cheaper material and much smaller in size, about 1 to 3 inches in circumference. This allows us to use smaller storage tanks, hence reducing the overall cost.”

The method Goswami and his team developed uses encapsulated salt balls with ceramic coverings to withstand higher temperatures Jaspreet Dhau, a research scientist in the College of Engineering, said.

“We have encapsulated the salt balls with a ceramic covering, which allows us to heat the balls at a much higher temperature,” Dhau said. “Others are using metal coverings, but at such temperatures, the metal is ruined. In our case, the ceramic coverings do not react with molten salt.”

The salt balls melt to liquid at a high temperate and stay hot in the insulated tank, which turns water into steam. When the temperature cools, the salt is turned back into a solid.

Though Goswami is already trying to implement the technology outside the university, there are still modifications that need to be made.

“We are continuing to develop systems for storage up to 1000 degrees Celsius,” he said. “We are making a partnership with Kyocera, a ceramics company in Japan, to use their expertise in developing this storage material successfully.”

Currently, he said there are no cost-effective methods of storing solar energy for electric companies to use, which is the largest hindrance to the usage of solar energy.

Goswami said with his team, he hopes to make storage a very small part of the overall cost associated with solar energy.

“The cost of solar energy today is about $45 per kilowatt of hour used per month,” he said. “Our goal, which we hope to achieve in a year or so, is to reduce that cost to $15.”

USF is accumulating data in regard to solar energy, through experimentation, which Dhau said has not been present at the university before.

“There is a lot of computational data, which is available already, but experimental work is not there because of the lack of material that is present,” he said. “We are actively experimenting, which is allowing us to progress at a faster rate.”

Not many researchers around the world are exploring similar ideas, which makes this project so unique.

“People didn’t realize this method of storage in the past and are still new to this topic,” Dhau said. “We are revolutionizing the way energy is stored. Other institutes will begin to consider this as a vial storage device in solar power plants and other plants as well.”

Goswami said he thinks his research will revolutionize solar energy storage at a global level.

“Energy storage will be used for solar power plants and conventional power plants too,” he said. “I see a bright future for commercialization of this energy because of the conventional thermal power. It operates at a certain capacity, and at night, the production is much less. If our plan works, plants will be able to produce the daytime levels at night or in times where sunlight is bleak.”