Open AccessPower loss in the upper cut‐out wind speed interval
Author(s) -
Kristensen L.,
Højstrup J.,
Rathmann O.
Publication year - 2004
Publication title -
wind energy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.743
H-Index - 92
eISSN - 1099-1824
pISSN - 1095-4244
DOI - 10.1002/we.106
Subject(s) - wind speed , offshore wind power , wind power , geostrophic wind , wind profile power law , roughness length , meteorology , fetch , marine engineering , drag , wind gradient , environmental science , surface roughness , geology , engineering , climatology , aerospace engineering , physics , electrical engineering , geomorphology , quantum mechanics
Time series of mean wind speeds at several sites in Denmark have been used to estimate the power loss for wind turbines in the wind speed interval from where the operation has to stop at high winds to where a lower wind speed allows the operation to resume. For inland wind turbines the fractional loss is less than 0·25%. For offshore wind turbines it may be as high as about 1·5%. To facilitate the estimation of ‘dead zone’ power loss for offshore wind turbines, an engineering model for the sea surface state has been developed on the basis of a generalization of Charnock's roughness model and the geostrophic drag law. This model predicts the surface friction velocity and the surface roughness as functions of the geostrophic wind speed and the length of the water fetch. Copyright © 2004 John Wiley & Sons, Ltd.