Comparing Meso-Micro Methodologies for Annual Wind Resource Assessment and Turbine Siting at Cabauw

A summary of the initial results of the "NEWA Meso-Micro Challenge for Wind Resource Assessment" is presented. The objective of this activity, conducted in the context of the New European Wind Atlas (NEWA) project, is to establish a process for the evaluation of meso-micro methodologies in the context of wind resource and wind turbine site suitability assessment. A hierarchy of methodologies that rely on coupling mesoscale and microscale models is evaluated as a tradeoff between accuracy and computational cost in terms of relevant wind conditions for wind turbine siting such as annual energy production, turbulence intensity, etc. Besides integrated annual quantities, these metrics are analyzed in terms of atmospheric boundary-layer drivers at wind climate (mesoscale tendencies) and site characteristics (atmospheric stability). This is used to characterize errors leading to the identification of knowledge-gaps in the model-chain. This first phase of the meso-micro challenge analyzes Cabauw onshore met mast in horizontally-homogeneous conditions to focus the assessment on mesoscale-to-microscale downscaling methods rather than on site complexity. A second phase of the challenge will add sites in heterogeneous terrain conditions from the NEWA database of experiments.