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The Strict Relationship Between Surface Turbulence Intensity and Wind Shear Coefficient Daily Courses: A Novel Method to Extrapolate Wind Resource to the Turbine Hub Height

Based on power law, a novel method is proposed to extrapolate surface wind speed ( v ) to the wind turbine (WT) hub height, via prediction of the wind shear coefficient (WSC) daily course, by only using the surface turbulence intensity ( I ) daily course. Work’s main outcome is a strict (almost 1:1) relationship between WSC and I daily courses which was found after applying a linear regression analysis. Practical usefulness of this finding for wind energy applications is straightforward, as merely using I values routinely collected at surface heights a WSC predicting model may be used to fairly estimate energy yield at WT hub height. A 2–year (2012–2013) dataset from the meteorological mast of Cabauw (Netherlands) was used, including 10–min records collected at heights of 10, 20, 40, and 80 m. Methods were trained over a 1–year period (2012) and then validated over an independent 1–year period (2013). WT hub heights of 40 and 80 m have been targeted for the extrapolation, being accomplished based on I observations at two surface levels: 10 and 20 m. As a result, good scores were returned by the proposed method over the most challenging height intervals: between 10 and 80 m, a 5% mean bias was achieved in extrapolated v values and at worst a 11.51% in calculated energy yield; between 20 and 80 m, extrapolated v values were biased by 2%, while energy output at worst by 6.62%.