05 March 2010
05 March 2010
University of Dayton Research Institute (UDRI) has been awarded $270,000 in Ohio Third Frontier funds for research to design and test structures and materials for composite wind-turbine towers that will stand as much as 65 feet taller than the steel towers currently used in wind farms around the world.
“The U.S. Department of Energy has reported that by 2030, 20 percent of all electricity generated in the U.S. could be supplied by wind. But a number of design and material advancements need to be made in wind-turbine technology before that can happen,” said Brian Rice, Division Head for Multi-Scale Composites and Polymers at UDRI.
Wind turbine towers have to be strong enough to not only carry the weight of the turbine – which can be as much as 100 tons – but also to resist buckling under the stress of the rotating machinery, Rice said. To accommodate weight and stress, steel monopoles are pre-fabricated in sections as large as 14 feet in diameter and 70 feet long, then trucked individually to the wind site to be fit together and installed on a concrete foundation. In finished form, the average utility-grade tower height is about 80 meters, roughly 265 feet.
But the wind industry has been setting its sights on a new standard for tower height at 100 meters (328 feet), Rice said. Putting larger turbines atop taller towers facilitates access to greater wind speeds, which improves operating performance and cost. As the size of wind turbines continues to grow, however, so grow the problems and expense associated with transporting and building the towers.
“If you increase the height of the tower, you have to increase its diameter as well,” Rice said. “Which means that next-generation wind turbines will require towers that will be too large to ship via highway, even in sections.”
The solution, Rice said, is in composites – fibreglass and resin tower sections that would be manufactured at the wind farm using raw materials trucked to the site. The manufacturing operation would be staffed primarily by local labour.
“On-site fabrication eliminates the transportation problems and makes more sites accessible to wind power development,” Rice said. “Even today there are good potential wind farm sites in remote or hilly locations, but there aren’t sufficient roads to allow for trucking in steel towers; the new design would solve that problem as well.” In addition, the corrosion-resistant properties of composites will be far more suited than steel for off-shore wind farms, which are just starting to be developed in U.S. waters, he added. The Ohio program team, comprising lead partner Ershigs Inc. in Manchester, UDRI and Edison Materials Technology Center in Dayton, WebCore Technologies in Miamisburg, Owens Corning in Columbus, and Ashland Performance Materials in Dublin, has been working for more than two years to test materials and coupon samples and is now prepared to move into product demonstration, Rice said. The partners will design, analyze, build and test a series of progressively larger components with a goal of completing and testing a full-scale 100-meter composite tower.
“In full size, these will be some of the largest composite structures ever built,” he said.
In a complementary program, UDRI researchers are working on an Air Force advanced-materials contract to develop smaller composite wind turbines to generate electricity in areas of low-speed wind. The smaller turbines, which can be trucked in sections and erected in remote military installations, will also serve well in civilian settings where wind is low and energy demand not great, such as rural areas and industrial parks.
The $700,000 Air Force program awarded in 2009 has received $1 million in additional funds for year two, to begin in May.
Cobra International will showcase a range of composite products at CAMX 2018, including carbon fibre components for the automotive, transportation, marine, water sports and luxury sectors.
UK company Prodrive Composites has developed a process for manufacturing recyclable composite components that can satisfy future end-of-life requirements without any compromise in the performance of the original parts. The company says the P2T (Primary to Tertiary) process not only simplifies recycling, but endows a composite material with the potential to fulfil three or more useful lifetimes.
Designers at Elemental Motor have utilised tailored fibre placement (TPF) to extend the use of carbon composites in its RP1 sports car.