Research initiated by the University’s Department of Mechanical and Aerospace Engineering recently earned the Segmented Ultralight Morphing Rotor Wind project a $3.56 million grant from the Department of Energy’s Advanced Research Projects Agency-Energy. The project, conducted by institutional and industry experts, aims to invent a versatile blade for offshore wind turbines that can withstand extreme weather conditions and reduce the cost of energy.
Led by Eric Loth, the University’s Mechanical and Aerospace Engineering Department chair and Rolls-Royce Commonwealth Professor, the project began six years ago when Loth and his colleagues from the University started working with the National Renewable Energy Laboratory in Colorado.
“They have a test facility there where they can get winds up to 100 miles per hour,” Loth said. “They look at how to make turbines as efficient as possible so that the cost of energy is reasonable.”
Following the initial funding, Loth and the original team at the University expanded to include leaders in aerodynamics, structural design and control design from the University of Colorado Boulder, the University of Illinois at Urbana-Champaign, the Colorado School of Mines and Sandia National Laboratories in New Mexico. Along with an industry advisory board made up of several prominent wind turbine manufacturers, the group designed specialized blades with a segmented structure. The new model enables them to adjust to changing wind speeds and directions, maximizing the amount of energy captured.
The team was inspired by palm trees, which are flexible and lightweight.
“They can withstand hurricanes, and we were trying to solve the problem that as wind turbines become larger and larger.” Loth said. “And they start to move offshore into the ocean — the Atlantic Ocean in particular — we have lots of hurricanes.”
In the past, blade structure has been rigid in order to withstand extreme weather and high speed winds. With a more flexible approach, the potential for the blades to bend and hit the turbine column. To prevent the curving blades from striking the tower, Carlos Noyes, a graduate student in the Department of Mechanical and Aerospace Engineering, helped study the effects of placing the rotors downwind.
“Most wind turbines you can't allow for bending because then they will bend back and hit the tower,” Noyes said. “But what we did is we went downwind, which allows for bending, because the rotors are behind the tower.”
In addition, as Noyes noted, without the need for a rigid structure, the project can reduce the weight of the blade material, further cutting the cost of production and of energy.
After coming together to perfect their creative blade design and spending several months drafting a proposal, the SUMR Wind team presented their idea to ARPA-E and was awarded an open-access grant in fall 2017.
The next step is to conduct the first test with a subscale model in the Colorado mountains this summer at the National Wind Technology Center, part of the National Renewable Energy Laboratory. The demonstration blades will be tested throughout the summer, and if all goes well, Loth and his associates intend to build a wind turbine taller than the Eiffel Tower. They predict this 50-megawatt model will reduce the cost of energy by 50 percent by 2025 and incentivize a transition to wind energy in the United States.
“I would say in general the ultimate goal is to promote wind energy in the U.S. by making it lucrative and economic, and lowering the price to where it’s equivalent to fossil fuels,” Noyes said. “Some people say the only way to have renewable energy is if the government intervenes and subsidizes it and heavily taxes fossil fuels … But I think, given a little bit more research and a little bit more time, we won’t need that.”
Not only does the SUMR Wind team hope to be a large part of the United States’ transition to renewable energy resources, but it also wants to increase American energy independence, beginning with turbines off the Virginia coast.
“We’re actually behind the world so to speak in offshore wind energy,” Loth said. “We’re hoping this can help leverage the United States to really jump ahead, to get into what’s really going to be an economy and a manufacturing center for the future in offshore wind turbines.”