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Two new research initiatives on blades for horizontal axis wind turbines have been launched by Sandia National Laboratories at Bushland, Texas. Bushland was the site of US research in the late 1970s on vertical axis wind turbines. The first project, called the Term Inflow Structural Testing (LIST) project, headed by Herb Sutherland, is an intensive data gathering exercise using three 16 metre rotor turbines formerly sited at Palm Springs, California. "It's often too expensive to do research and development with the large turbines," Sutherland explains. "Once we come up with a design that works at that smaller size, we will scale it up."

Automated instruments will measure wind speed, wind direction, and blade loads at frequent intervals -- 30 per second -- over a year. "We are particularly interested in wind loads created by large wind gusts passing through the rotor," Sutherland says. "A single large event can reduce the life of a turbine blade by half."

The second project is the Blade Manufacturing Initiative (BMI), led by Tom Ashwill. "We will be looking at advanced materials, better manufacturing processes, and more efficient blade designs, all in an effort to develop blades that are lighter, more reliable from a structural standpoint, and less expensive," Ashwill says. "Currently, blades are sufficiently strong, but they cost too much. As commercial machines get bigger, this could be even more of a problem."

Wind turbine blades are typically built by hand, which according to Ashwill "tends to create small imperfections that cause premature failures of wind turbine blades." Over the next few years, Ashwill will be studying automated processes and advanced moulding techniques to build better blades cheaper.