This is an excerpt from the Second Quarter 2013 edition of the Wind Program R&D Newsletter.

The U.S. Department of Energy (DOE) and Sandia National Laboratories (SNL) are designing a modern, research-quality wind turbine rotor for use at the new Scaled Wind Farm Technology (SWiFT) site at Texas Tech University in Lubbock, Texas. Designated as the National Rotor Testbed (NRT), the new rotor will be a public resource used to accelerate important rotor innovation and to conduct complex flow and turbine-to-turbine interaction research that will increase the efficiency of wind power plants and lower the cost of electricity.

The SWiFT facility, which was commissioned this July, is unique in that it utilizes wind turbines that are large enough to represent the physics relevant to utility-scale machines, yet small enough to be extremely cost effective by comparison. It features 1980s-era Vestas V27 225-kilowatt turbines with 27-meter (m) diameter rotors. Although the aerodynamic and structural technologies used in the original rotors of the V27 enabled a cutting-edge product in their own time, today's modern turbines (with capacity ratings of 1.5 to 3 megawatts and rotor diameters of 70 to 120 m) are able to take advantage of the fruits of an additional 20+ years of wind turbine rotor technology research. Modern rotors are designed to a new level of optimal aerodynamic and structural efficiency, but they have their own challenges: acoustics, controls, sensing, aerodynamics, and structural dynamics. The goal of the NRT is to provide a greater understanding of these challenges as well as wind plant complex flow issues.

The new SNL rotor design that will be completed by the end of 2013 is a small, or subscale, version of a modern utility-scale rotor and uses the same design drivers and technology as the bigger rotors. To ensure that the new subscale design offers an accurate representation of larger rotors, DOE and SNL sought input from several industry partners. The subscale nature of the NRT blades at SWiFT will enable high-fidelity measurements and sensing along with accurate simulation of the larger rotors, which is logistically simpler and more cost effective than relying on equivalent megawatt-scale test turbines. After the blades have been manufactured, they will replace the existing rotors on the DOE turbines at SWiFT.

Aerodynamic and structural design information about the new rotor, as well as the SWiFT turbines, will be made publicly available at the conclusion of the project. In its role as an open-source public resource, the NRT will provide a previously unavailable vehicle for public research at a scale that is physically relevant to solving today's cutting-edge rotor innovation and turbine-to-turbine interaction challenges.