Hi Ivan,
The wind speed data in the NSRDB is
coarse reanalysis data from NASA
MERRA2
interpolated to the NSRDB grid using simple methods
(inverse distance weighted for speed, nearest neighbor for direction, and linear through time).
The MERRA2 wind speed data is at 2 meters above the ground.
This data is suitable for use for solar collector temperature calculations but should not be used for wind power calculations.
Best regards,
Paul.