Vertical Extrapolation Methods

Assessing Long-Term Hub Height Wind Specifications

Numerous wind energy yield assessments are based on measurements carried out with a met mast located at a lower height than the hub of the planned wind turbine. This article deals with the issue of vertical extrapolation of measured wind characteristics. It benchmarks four distinct empirical extrapolation methods based on a simple measurement set-up – two heights of anemometers, a wind vane, a short-term measurement of a remote sensing device (lidar, sodar) and different assumptions about the wind shear (α). These methods were tested on nine of Maïa Eolis’ 80-metre met masts in France and benchmarked to a WAsP calculation.

By Olivier Coupiac, Maïa Eolis, France