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Small Wind Turbine Tests and Testing Approach

The National Renewable Energy Laboratory (NREL) has testing capabilities that are accredited by the American Association of Laboratory Accreditation (A2LA).

The suite of tests conducted on small wind turbines includes acoustic noise emissions, duration, power performance, power quality, safety, and function. Learn about NREL's small wind turbine research projects. Each of the tests is briefly described below. Tests are performed to International Electrotechnical Commission (IEC) standards and in compliance with NREL's A2LA-accredited Quality Assurance (QA) system.

Acoustic Noise Emissions

Acoustic noise emissions testing summarizes noise levels emitted from the turbine at different wind speeds. Sound data are recorded (one tower height plus half a rotor diameter downwind from the tower base) and processed using Noiselab software. Acoustic noise testing is conducted according to IEC Standard 61400-11.


Duration testing is performed to summarize the turbine's structural integrity, dynamic behavior, and reliable operation over a minimum of 6 months at different wind speeds. Test data are sorted monthly into time classes specified by the standard. Duration testing is performed according to IEC Standard 61400-2.

Power Performance

Power performance testing produces a power vs. wind speed graph to summarize the turbine's power generation performance at different wind speeds. The power curve is then used to estimate Annual Energy Production (AEP). This test is performed according to IEC Standard 61400-12-1, referencing Appendix H for small turbines.

Power Quality

Power Quality testing includes assessment of power, flicker, harmonics levels, and grid protection for compliance with the standard. For small turbines, power quality tests are performed for 3-phase systems only. Power quality testing is performed according to IEC Standard 61400-21.

Safety and Function

Safety and function testing is performed to verify that the turbine displays its designed behavior and that provisions relating to personnel safety are properly implemented as represented by the manufacturer. Features tested are drawn from the wind turbine documentation. The testing is conducted in accordance with IEC Standard 61400-2.