With the rapid transition to renewable energies, the North Sea has seen a quick development of offshore wind farm deployments. According with the North Seas Energy Cooperation agreement, the total offshore installed capacity in Europe is planned to further increase from approx. 26 GW in 2022 to 120 GW by 2030 and 300 GW by 2050. Wind energy technology is necessary to help us to reduce carbon emissions, but it is also necessary to understand its future impacts.

The animation is based on a near future wind farm scenario for the North Sea with an installed capacity of approx. 150 GW. The effects of the wind turbines and the interaction of wind farm clusters with the atmosphere are simulated with the regional climate model COSMO6.0-clm, whose domain and vertical extent (a subset of the data from 50 to 500 m) are indicated by the black outlines. The wind farm areas are shown as semi-transparent gray shaded areas. The wind turbines have a direct influence on the low atmospheric circulation by reducing the wind momentum and increasing turbulent kinetic energy downstream the air flow in so-called wakes. Under stable atmospheric conditions, such wakes can be transported more than 50 km away from the wind farm, potentially affecting neighboring wind farms. Wind speed anomalies caused by wind farms are calculated from the wind farm scenario and a simulation without them. They are denoted by 3D isosurfaces marked in semi-transparent dark blue (-2 m/s) and brownish (+2 m/s) colors.

The effects of wind momentum reduction and increase of turbulence lead to local changes of the air properties that influences the air-sea interaction. The colors shown at the sea surface represent the latent heat flux. This heat exchange depends on the wind speed, moisture content in the air, and the air-water temperature gradient. Negative/positive values (in blue/red) denote a decrease/increase in energy transfer from the atmosphere to the ocean causing a warming/cooling effect in the sea surface temperature with respect the simulation without wind farms. In the process, water mass is gained/lost through surface evaporation/condensation which also influences the sea surface salinity.

Simulation: Alberto Elizalde, Hereon

Visualization: Michael Böttinger, DKRZ

The video is also available on Youtube: https://youtu.be/WnXrgzUYwKE