GE, NREL, Virginia Tech introduce non-composite wind blade design

GE, the National Renewable Energy Laboratory and Virginia Tech University have developed a new wind blade design that wraps architectural fabric around a metal spaceframe, like a fishbone. It could cut blade cost by 25 to 40 percent.

GE (Niskayuna, N.Y., USA), Virginia Polytechnic Institute & State University (Blacksburg, Va., USA) and the National Renewable Energy Laboratory (NREL, Boulder, Colo., USA) announced on Nov. 28 that they will begin work on a project that could fundamentally change the way wind blades are designed, manufactured and installed.

According to GE, this new blade design could reduce blade costs 25 to ­40 percent, making wind energy as economical as fossil fuels without government subsidies. GE’s research will focus on the use of architectural fabrics, which would be wrapped around a metal spaceframe, resembling a fishbone. Fabric would be tensioned around ribs which run the length of the blade and specially designed to meet the demands of wind blade operations. Conventional wind blades are constructed out of fiberglass, which GE says is heavier and more labor- and time­-intensive to manufacture.

“GE’s weaving an advanced wind blade that could be the fabric of our clean energy future,”
says Wendy Lin, a GE principal engineer and leader on the U.S. Department of Energy’s
Advanced Research Projects Agency (ARPA­E) project. “The fabric we’re developing will be tough, flexible and easier to assemble and maintain. It represents a clear path to making wind even more cost competitive with fossil fuels.”

GE says advancements in blade technology will help spur the development of larger, lighter turbines that can capture more wind at lower wind speeds. The company says current technology doesn’t easily allow for construction of turbines that have rotor diameters exceeding 120m/394 ft because of design, manufacturing, assembly, and transportation constraints. Wider, longer wind blades are tougher to move and maneuver, and molds which form the clamshell fiberglass structure cost millions of dollars to acquire. GE says its new fabric-­based technology would all but eliminate these barriers.

With this new approach to making wind blades, components could be built and assembled on site, meaning design engineers no longer have to concern themselves with manufacturing and transportation limitations. Taken together, GE says these improvements will help reduce start­up costs and the cost of wind-­generated electricity in general.

GE says it’s estimated that to achieve the national goal of 20 percent wind power in the U.S., wind blades would need to grow by 50 percent­­ a figure that would be virtually impossible to realize given the size constraints imposed by current technology. Lighter fabric blades could make this goal attainable.

“Developing larger wind blades is the key to expanding wind energy into areas we wouldn’t think of today as suitable for harvesting wind power. Tapping into moderate wind speed markets, in places like the Midwest [U.S.], will only help grow the industry in the years to come,” Lin adds.

The use of fabrics to reduce weight and provide a cost­-effective cover dates back to the World War I era, when it was used on airplanes. Over the years fabric has proved to be rugged and reliable and GE has already begun using this spaceframe/tension fabric design in the construction of wind towers for better aesthetics, cost  and protection.

The $5.6M ARPA­E project will span three years. GE’s blade architecture will be built to achieve a 20-year life with no regular maintenance to tension fabrics required.