Model results of effects of offshore wind farms for MSFD : OWF 2024

Following a similar approach as described in the WOZEP report (Zijl et al., 2021b), Deltares has calculated the hydrodynamic impacts of the expected presence of Offshore Wind Farms (OWFs) in the North Sea in the year 2024. To this end, simulations with the 3D DCSM-FM hydrodynamic model were performed, with and without OWFs. Before this model was applied, it was checked that a required change in software and hardware used did not significantly impact the model quality and output compared to the earlier WOZEP computations and the original model validation. For the present study, more detailed information on pile density and diameter of the monopiles is available, compared to the earlier WOZEP study. Analysis has shown that this results in a lower combined flow blocking surface in the water column for recent and planned windfarms, compared to the original WOZEP assumptions. Computations with both approaches have shown that the result is a general decrease of computed impacts when using the more detailed approach as used for the present study. This holds in particular for the more recent windfarms with a low pile density and larger diameter of the monopiles. The report describes expected impacts due to the presence of OWFs with respect to salinity, temperature and the stratification thereof, as well as the M2 tidal amplitude and phase, residual currents and bottom shear stress.