Observations of Wind Turbine Wake and Wind Plant Wake in the Columbia River Gorge Using a Scanning Doppler Lidar

As part of the second Wind Forecast Improvement Project (WFIP2) field campaign, a large suite of instrumentation was deployed to the Columbia River Gorge from October 2015 to March 2017. The array included two scanning Doppler lidars deployed by the Chemical Sciences Division, NOAA. In this presentation measurements from one of the scanning lidars, located at Arlington, OR which is about 2 km east of a wind farm are discussed.

Wakes from wind farms span two major scales. The smaller scale wakes are the wakes from individual wind turbines (wind turbine wake) while the larger scale is the wake from the whole wind plant (wind plant wake). This presentation will show measurements from the scanning lidar at Arlington that attempted to capture these two scales of wakes.

A unique technique to process the lidar observations made during the WFIP2 campaign allow deriving wind profiles over several kilometers downstream of the wind farm near Arlington, OR using one scanning lidar. These observations will be used to characterize whether the wind plant wake and its evolution can be measured using a Doppler lidar. The impact of wind plant wakes on model evaluation will be investigated.

At the end of the WFIP2 campaign, the scanning Doppler lidar in Arlington, OR was tasked with measuring the wakes from the wind farm to the west of the site. These observations made post-WFIP2 included a closely spaced stack of conical sectors centered on the wind turbines of interest. This measurement was performed for a period of two weeks. These measurements allow resolving the individual wind turbine wakes. These measurements will be used to show the evolution of wakes from multiple wind turbines at different heights in complex terrain.