Ludewig E. On the Effect of Offshore Wind Farms on the Atmosphere and Ocean Dynamics

Springer, 2015. — 177 p.
Nowadays, renewable energy resources play a key role in the energy supply discussion, and especially a heightened interest in wind energy induces intensified installation of wind farms. In the course of a larger demand of renewable energy, offshore wind farms (OWFs) gain increasingly in popularity since over-sea yields are larger and more reliable than over land. In this context, Germany adopts the position of a pioneering nation due to its national interurban offshore wind energy program comprising an intensified construction of wind turbines in the Baltic Sea and, mainly, North Sea. Against this background, it becomes particularly urgent to inquire whether and to what extent such OWF expansion affects our oceans and local climates. OWFs excite wind speed reduction downstream of wind farms, the so-called wake effect, which impacts the atmosphere’s boundary layer; locally disturbs the wind characteristics; and in turn affects ocean dynamics. To study the whole complex in more detail, investigations comprise model simulations and measurements. Used models are the atmosphere model METRAS (MEsoscale TRAnsport and Stream model) and the ocean model HAMSOM (HAMburg Shelf Ocean Model). METRAS simulations were generated in collaboration with and by courtesy of the Institute for Meteorological of the University of Hamburg. These METRAS data represent the meteorological forcing for simulations of the ocean. Measurements were taken around German test wind farm alpha ventus supported by the German Federal Maritime Service (BSH). Analysis regarding OWF effect on the atmosphere and ocean comprises two main studies to determine possible OWF effects and their physical appearance in theory and to estimate possible future integrated changes of the North Sea’s marine system based on the offshore construction plan for 2030. Investigations consider different amounts of wind turbines, wind speeds and directions, ocean depths, and forcing assumptions. Model results and measurements show a reasonable agreement supporting the principle validity of the used model approach.