Wake effects at FINO 1 - new observations since the construction of Trianel Borkum Borkum Riffgrund I wind farms

摘要

Wind speed data from the FINO 1 platform in the North Sea have been investigated to characterise the wind conditions under consideration of the new wind farms constructed to the West of the platform. The main parameters considered were turbulence intensity (TI) obtained from cup anemometers mounted on the mast and wind profiles obtained from two vertical scanning Lidars on FINO 1 and the nearby converter station at Alpha Ventus. TI indicates significant broadening of the wakes from the northern most wind turbine cluster; an increase in TI is seen in what should nominally be a free sector to the NNW. Wind speed reductions as large as 7 m/s at the extreme are found in the wake of Alpha Ventus. Wind profiles up to a height of 200 m still show a reduced wind speed compared to an upwind measurement at the same height. This indicates that wind speeds are significantly influenced well above the blade tip height. Finally, turbulence spectra are investigated. Wakes from single wind turbines show explainable characteristic, however wakes from wind farms show far more variability, highlighting the complexity of wake behaviour.