An inter-comparison study on the impact of atmospheric boundary layer height on gigawatt-scale wind plant performance

Abstract. The height of the atmospheric boundary layer (ABL) exerts a significant influence on flow behavior within wind farms and directly impacts their performance. This study investigates how variations in ABL height and capping inversion layer thickness affect the efficiency and power output of a gigawatt-scale wind farm. Five advanced numerical approaches, ranging from high-fidelity large-eddy simulations (LESs) to Reynolds-averaged Navier–Stokes (RANS), are used to model farm-scale flow dynamics under shallow (∼150 m) and deep (∼500 m) ABL conditions. The results consistently show that shallow ABLs increase flow blockage and turbine wake interactions, leading to reduced power production. In contrast, deeper ABLs promote enhanced wake recovery and increased overall energy yield. These trends were observed across all solvers, demonstrating the robustness of the findings. Notably, while some quantitative differences emerged depending on modeling fidelity and computational domain size, the overarching trends remained consistent among the participating research institutions and industry partners. The simulation cases performed are complex, and the results of the different methods show a variation of up to 10 %, and further research is needed to limit this gap. Based on these results, it is not clear to what extent the variation depends on the fidelity level of the models used. The study concludes that ABL height and stability are critical parameters to consider in wind energy siting and turbine layout design to optimize performance across varying atmospheric conditions.