Researchers at the Department of Energy’s Sandia National Laboratories are developing ways to lower the cost of wind generation by enabling turbines to produce more power. Although current wind turbines can be cost-effective in extremely windy areas, design improvements are needed to make wind turbines cost competitive in areas with less wind. Research is centered on increasing rotor sweep areas and reducing blade rotation rates.
“We are looking at methods of building larger, stronger blades using a hybrid of carbon graphite fibers and fiberglass that sweep a greater area without greater cost,” says Paul Veers, manager of Sandia’s Wind Energy Technology Department. “By next summer we expect to have experimental blades ready for testing that we believe will be lighter and stiffer than blades currently used in the industry.”
During the past ten years, the cost of wind energy has fallen dramatically — ranging from to 2.5 to 5 cents/kWh in the windiest sites. To make turbines cost-effective at sites with modest winds, further cost reductions are necessary in critical subcomponents of design, manufacturing, and system integration, says Veers.
Today’s most popular commercial wind turbines have 115-foot blades on towers ranging in height from more than 200 feet to as much as 260 feet and producing about 1.5 MW each. Most blades are made of fiberglass, although at least one European manufacturer uses wood.
Tom Ashwill, who leads the blade development team, says that the research blades will be built at sub-scale sizes of about 30 feet in order for the researchers to cost-effectively grapple with issues such as fiber material form, degree of carbon/glass hybridization, manufacturability, and other traditional issues including aerodynamics, structural strength, and reliability.
It is expected that qualities of successfully tested subscale blades can be scaled up to carbon/glass blades more than 160 feet long attached to turbines on 330 feet towers and that produce 2 to 5 MW each.
By next summer the researchers hope to have six to 12 different blades to test at the National Wind Technology Center near Boulder, Colo., using its large blade test facilities, and at the Department of Agriculture’s research station in Bushland, Texas, using three experimental turbines.
“We expect over the next few months to make some real inroads to developing better blades for turbines,” Ashwill said. “It’s a project we are all looking forward to.”