From KlimaNachrichten

By KlimaNachrichten Redakteur

Professor Gerd Ganteför was not insulted when he reported on the so-called wake effect of wind turbines on the high seas in the spring of 2024. Wind turbines in wind farms not only take the wind away from each other, they can also have an impact on the wind behind the turbines for up to 100 kilometres. In the meantime, the realization has also reached the operators. The company Orstedt, which is heavily involved in the so-called renewable energies, has some interesting results on its website.

In a convoluted way, it says that the plants in the network deliver less yield, which means that the profitability per plant decreases.
Overall, electricity production would increase with more wind farms, but so would the time up to which the investment per turbine would pay off. The return decreases if the calculated 4,000 – 4,500 hours of electricity generation per year are not achieved. The effect is likely to intensify with more and more wind farms. It’s like a downward spiral. Let’s see what the German answer to this is. It would not be surprising if this were to pay even more feed-in tariffs.

“The size of the German areas is not the decisive point. ” Theoretically, much higher capacities than 70 gigawatts could be built up there,” says Martin Dörenkämper from Fraunhofer IWES at the Oldenburg site. It is true that the shading effects would increase if the wind turbines were planned even more densely than before. But overall electricity production would still increase, even if the yield per plant were lower. The question is therefore not whether Germany has enough space for 70 gigawatts, but how many terawatt hours of electricity can be produced each year – and at what price. After all, the higher the power density and the lower the yield per turbine, the more difficult it becomes for the operator to refinance the construction and generate a return.”

Ganteför explains in his video that it is now possible to make the wake effect visible with the help of radar images from the Sentinel 2 satellite. In the spring, he was still ridiculed for the thesis. He points out that the wake effect can have various effects. On the one hand, there are the turbines on land, which could get less wind, the possible warming behind the turbines and also the influence on precipitation. Ganteför pleads for more research in this area. Two years ago, the Fraunhofer Institute Hereon already pointed out another problem. Another effect: The disruption of the stratification of the water can affect plankton production and that would be the beginning of the food chain.

“Another consequence of wake vortices is the reduction of shear-related processes at the sea surface. In other words, the turbulent mixing of the water surface caused by the wind is reduced dozens of kilometers around the wind farm.

Water is usually layered, e.g. a layer of warmer water lies on top of a layer of cold water.

The wind farms disrupt the natural stratification. Due to the reduced mixing, a more stable stratification of the water is favored. This was particularly noticeable during the decline in summer shifts. The natural sighting of the water is particularly striking in summer and decreases towards autumn. In the area of the wind farms, however, a more stable stratification outside the seasonal fluctuation was calculated.

“What do the results mean for the North Sea?

“The magnitude of the induced mean changes does not indicate serious local effects, but far-reaching structural changes in the system occur,” says Christiansen. “The changes in current and mixing are expected to affect plankton production and the structure of the food web and can influence the functioning of protected areas. It is therefore important to take these consequences into account when developing marine protection concepts,” says Hereon Institute Director Prof. Corinna Schrum and gives an outlook for the implementation of the results.However, further investigations are needed to analyse possible feedbacks on air-sea exchange. A change in this exchange has the potential to affect regional atmospheric conditions and ecosystem dynamics and will be the subject of further studies.”

That sounds anything but like science is settled.