Impact of coastal gradients on wind farm energy yield assessment: model comparison

Abstract This study presents, for the first time, measurements from the modern offshore Danish Kriegers Flak wind farm, located in the Baltic Sea and surrounded by external wind farms and a complex coastline. The performance of three widely-used models for energy yield assessment of wind farms is compared: the WRF mesoscale model with wind farm parameterization, the computational fluid dynamics code OpenFOAM using the actuator disc turbine model, and the Jensen engineering wake model in FLORIS. Error metrics and discrepancies between the simulations and measurements are thoroughly analysed for all sectors of the wind rose, considering a single inflow velocity. The results reveal that the performance of each model varies significantly depending on the analysed inflow sector and atmospheric stability. Differences in wake loss in the annual energy production (AEP) are compared between the models with AEP calculation capabilities, WRF and FLORIS. While the wake loss estimates in AEP closely align with the measured values, the discrepancy is influenced by the wind farm’s operational availability. One limitation of this study is the use of horizontally uniform inflow in OpenFOAM and FLORIS, whereas the terrain and its effects are only included in WRF.