Wind Energy Testing Support
Testing support includes structural, dynamometer, and field testing. Take a Facilities Tour to learn more about the test facilities at the National Wind Technology Center (NWTC).
Structural Testing
The NWTC structural test facility has been operating since 1990. It has been used primarily for structurally testing full-scale wind turbine blades for program subcontractors and wind industry partners. The present capabilities include fatigue testing, ultimate static strength testing, and several non-destructive techniques, such as photo-elastic stress visualization, thermographic stress visualization, and acoustic emissions.
Blade testing is required to meet wind turbine design standards, reduce machine cost, and reduce the technical and financial risk of deploying mass-produced wind turbine blades. Rapid growth in wind turbine size over the past two decades has outstripped the existing capabilities of the NREL's National Wind Technology Center, which operates the only facility in North America capable of full-scale testing of megawatt-size wind turbine blades.
NREL will continue testing blades up to 50 m in length at its facility in Colorado, but transportation issues were key to deciding to build the new blade test facilities near waterways. In 2007, the Wind Energy Program signed agreements with consortiums from Texas and Massachusetts to design, build and operate new facilities to test the next generation of giant wind turbine blades. The Commonwealth of Massachusetts Partnership and the Lone Star Wind Alliance in Texas will build facilities to test large wind turbine blades with an ultimate goal of testing blades up to 330 ft. (100m) in length.
Dynamometer Testing
Similarly, the 2.5 MW Dynamometer and Spin Test Facility at the NWTC is a test bed dedicated to the testing of wind turbine drive trains, drive train components, and power systems. NWTC staff conducts such tests as gearbox fatigue, wind turbine control simulations, transient operation, generator and power system component efficiency, and performance for the advancement of the U.S. wind energy industry. Previously, the only way to verify operating integrity throughout the turbine's full load envelope was to test a field prototype under severe conditions. This NWTC facility provides improved methods for full-system testing of wind turbine systems to identify critical integration issues before field deployment. The facility gives the U.S. industry an edge over strong European competition because it is the only facility of its kind in the world.
Field Testing
Field testing encompasses a wide range of activities to support both large wind technology and distributed wind technology activities. Such testing is typically conducted on full-scale turbines installed in the field, although it is also done on components and subsystem test articles. Field testing necessitates installation of sensors and transducers (e.g. strain gages, accelerometers) used to quantify loads on operating turbine structural components, noise emissions, output of electrical systems, and meteorological inflow conditions. The test devices are connected to special, rugged computer-based data acquisition systems. Large quantities of resulting data often require specialized processing and analysis to extract required information. Field tests measure turbine loads, acoustic emissions, power production, and power quality. Resulting loads data are essential in verifying computer simulation models of wind turbine configurations. Field test data are especially important when assessing viability of new, innovative turbine configurations, since models of such configurations often need tuning iterations with test data to establish necessary confidence levels.
Accredited turbine field data obtained through field testing are essential inputs to design evaluations needed to support certification and due-diligence. For wind turbines to be successful in the marketplace, both domestically and internationally, they must meet international standards for reliability, including ultimately the ability to be certified by standards bodies. Collection of reliability data in the field helps manufacturers identify technical improvements that can be made to evolve the technology.
Future testing activities that will improve the reliability and durability of wind turbines include:
- Developing improved life-cycle testing protocols and analytical methods;
- Developing a better understanding of design load characterization for enhanced reliability, durability and longevity;
- Performing durability and reliability testing for environmental extremes; and
- Identifying design elements necessary to achieve 20+ year operating life.