U to research wind energy storage

The research is funded by a $2 million grant the U won this summer.

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University of Minnesota researchers last week delved into research of offshore wind energy storage, thanks to a $2 million grant awarded this summer by the National Science Foundation.

The University won a competition for the grant money through the Emerging Frontier in Research and Innovation program.

University mechanical engineering professor Perry Li will be heading a team that includes researchers from the University of Virginia and Worcester Polytechnic Institute. The teamâÄôs goal is to research and design “large-scale energy storage for offshore wind turbines using compressed air,” Li said.

Currently, wind power accounts for 2 percent of the nationâÄôs electric power, producing 35,000 megawatts of electricity. However, a problem with wind turbines now is that they are inefficient, Li said.

Wind turbines generally generate more electricity at night when the winds are stronger, but demand for electricity is higher during the day, he said.

The solution is to create a storage system where air can be compressed and stored for use during peak hours.

“The idea is to store eight to 10 hours of energy from a three-megawatt wind turbine at a reasonable cost,” Li said.

Participating researcher Eric Loth, from the University of Virginia, described the storage system as similar to a hybrid car.

“We basically will have this storage tank, which instead of being the battery in your hybrid car is actually a compressed air and liquid storage called an accumulator,” Loth said.

“We basically can take the energy from the wind turbine and, using the accumulator, we can get a steady stream of energy coming out of our wind turbine platform.”

A previous attempt to store energy from wind turbines resulted in converting the energy into electricity and then storing it in a battery. This method creates waste and often the batteries are not strong, Li said.

“The holy grail of wind power is to figure out the storage capacity,” said Rhonda Zurn, program director for the College of Science and Engineering .

Research into storing wind energy could prove monumental in the United States, Li said. The U.S. Department of Energy is looking to reach a goal of obtaining 20 percent of the nationâÄôs electricity from wind power by 2030.

“Since the demand and supply cycle [for wind energy] is different, if you donâÄôt have the storage capabilities, you would need a lot more wind turbines,” Li said.

While the concept of wind storage is the goal of the proposed research, obstacles still arise.

Compressing air from the windmills into 500 cubed-meters space would provide about eight hours of energy.

However, the process would produce excess heat at temperatures of nearly 2,600 degrees Fahrenheit.

Li and his team at the University will look into transferring this unwanted heat. They are looking to either release the heat into the environment or recycle the heat into energy, Li said.

The research is currently in its conceptual stage, Loth said. The project will go through an analysis and experimental stage before researchers put everything together.

Loth hopes to be able to build a working prototype in the near future but understands it will require another grant for an offshore wind turbine to be built. He predicts creating the model will cost up to another $2 million.

“There is a lot of emphasis from the Department of Energy toward offshore wind turbines,” Loth said. “I think we fit really well into that new vision.”