Remote Sensing Product Reduces Yaw Misalignment, Improves Turbine Performance

September 9, 2014 By Karen Henry

Wind Iris-energy-manageA collaborative research project at the US Department of Energy’s National Renewable Energy Laboratory (NREL) has shown that the Wind Iris nacelle-mounted light detection and ranging (LIDAR) from Avent Lidar Technology effectively identifies wind turbine yaw misalignment, allowing users to improve wind turbine performance.

This is the first independent scientific field study validating the benefits of using turbine mounted LIDAR to correct rotor-induced yaw misalignment. LIDAR is a remote sensing method used to examine the surface of the Earth.

The research focused on the optimization of turbine performance using forward-looking wind LIDAR measurements, with a focus on improving power output by correcting yaw misalignment and reducing turbine O&M costs through improved load mitigation.

The research was conducted in collaboration with Avent Lidar Technology and Renewable NRG Systems.

Wind turbines traditionally rely on a wind vane mounted on the rear of the nacelle to measure the wind direction in order to control the yaw position of the turbine, NREL noted in a press release. Certain factors, like rotor-induced wakes, can lead the vane to measure the wind direction inaccurately. The main focus of the project was to use LIDAR to measure the wind direction ahead of the rotor and design a corrective function. The correction function reduced the yaw misalignment and improved power capture in below rated power wind speeds.

The study also found that after implementing the corrective function based on Wind Iris readings, turbine energy output increased. It is estimated that LIDAR-based yaw correction will increase the annual energy production (AEP) 2.4 percent for a 7.5-degree misalignment.

Following the evaluation of static yaw misalignment correction, NREL, Avent and Renewable NRG Systems will explore the use of LIDAR measurements to actively control the wind turbine.

The Wind Iris is the only industry proven turbine LIDAR for power performance verification and optimization applications. It measures the horizontal wind speed and direction at hub height from 40 meters to 400 meters upwind of the turbine.

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