American WAKE experimeNt (AWAKEN)

Where: Central Oklahoma

When: 15 August - 15 September 2023

lidar in the truck bed — PUMAS near the NREL wind research facility in Arvada, CO. Photo: Richard Marchbanks, NOAA

The American WAKE experimeNt (AWAKEN) is a U.S. Department of Energy (DoE) project led by the National Renewable Energy Laboratory (NREL) to conduct a multi-institutional, long-term (2021-2024) study in the U.S. midwest to understand the interaction between wind farms and their surrounding environment and improve the performance of wake models.

To support the overall AWAKEN science objectives, CSL deploys the PickUp based Mobile Atmospheric Sounder (PUMAS) Micro-pulse Doppler lidar (MicroDop) to measure wake behavior downwind of the King Plains wind farm providing motion-compensated measurements of wind flow and turbulence downwind of this large wind farm in central Oklahoma. These unique measurements will provide for the first time insight not only into the temporal and vertical variability of wind flows available from stationary scanning lidars, but will also reveal spatial variability of simultaneously measured characteristics of the horizontal and vertical structure of wind flows modified by operating wind turbines.

wind farm and monitoring site locations in Oklahoma — CSL deploys PUMAS to measure wake behavior downwind of the King Plains wind farm in Garfield County, Oklahoma. Red dots are DoE ARM (Atmospheric Radiation Measurement) Southern Great Plains (SGP) instrument sites.

In conjunction with other remote sensors, the PUMAS motion-stabilized lidar measurements through the boundary layer will be used to study wind flow and turbulence modified by wind farms and wake dynamics along tracks at different distances from the wind farm.

Important science questions include:

How far downstream does a wind plant wake persist?
How do the dynamics of the wind farm wake (intensity/recovery/meandering) vary with atmospheric conditions/terrain?
How does the wind plant wake affect the local climate downstream?

To prepare for AWAKEN, several PUMAS test drives were conducted around wind farms near Sterling (2021) and Limon (2020, 2023) in Colorado to establish measurement capability, driving and scanning patterns, and to study dynamic processes upwind and downwind of turbine clusters.