The large-scale impact of anthropogenic mixing by offshore wind turbine foundations in the shallow North Sea

Frontiers in Marine Science

Marine Science

Nils Christiansen¹  Jeffrey R. Carpenter¹  Ute Daewel¹  Nobuhiro Suzuki¹  Corinna Schrum² 

[1] Institute of Coastal Systems - Analysis and Modeling, Helmholtz-Zentrum Hereon, Geesthacht, Germany;Institute of Coastal Systems - Analysis and Modeling, Helmholtz-Zentrum Hereon, Geesthacht, Germany;Institute of Oceanography, Center for Earth System Research and Sustainability, Universität Hamburg, Hamburg, Germany;

关键词: offshore wind energy;    wind turbines;    wakes;    turbulent mixing;    stratification;    modeling;   

DOI  :  10.3389/fmars.2023.1178330

 received in 2023-03-02, accepted in 2023-04-27,  发布年份 2023

来源: Frontiers

【 摘 要 】

Structure drag from offshore wind turbines and its physical impacts on the marine environment of the German Bight are investigated in this study. The flow past vertical cylinders, such as wind turbine foundations, and associated turbulent mixing has long been studied, but questions remain about anticipated regional implications of offshore wind infrastructure on physical and biogeochemical conditions. Here, we present two existing modeling approaches for simulating wind turbine foundation effects in regional ocean models and discuss the problematic use of very high resolution in hydrostatic modeling. By implementing a low-resolution structure drag parameterization in an unstructured-grid model, we demonstrate the impacts of monopile drag on hydrodynamic conditions, validated against recent in-situ measurements. Although the anthropogenic mixing is confined at wind farm sites, our simulations show that structure-induced mixing affects much larger, regional scales. The additional turbulence production emerges as the driving mechanism behind the monopile impacts, leading to changes in both the current velocities and stratification, with magnitudes of about 10%, similar in magnitude to regional annual and interannual variabilities. This study provides new insights into the hydrodynamic impact of offshore wind farms at their current development levels and emphasizes the need for further research in view of potential restructuring of the future coastal environment.

【 授权许可】

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Copyright © 2023 Christiansen, Carpenter, Daewel, Suzuki and Schrum