Wind energy in the forest: ?I just want to make it tolerable.“

This summer, Lake M?hne in the German state of North Rhine-Westphalia will once again be teeming with people. Families will meet up for a swim, sports enthusiasts will cycle or hike around the lake. Sailors and surfers will cut through the glistening water. As they do, all of them will look out over a natural paradise, the 600 km2 Arnsberg Forest - and soon perhaps over one of the largest wind farms in Germany.

The reason this might happen is a new law that aims to help Germany become climate-neutral by 2045. The "Wind Energy on Land Act" (WaLG) sets area targets for the expansion of wind energy for the federal states. North Rhine-Westphalia must designate 1.8 per cent of its land area for wind energy by 2032. In order to achieve this target, construction should also be permitted in forests. In December 2022, the Ministry of Economic Affairs, Industry, Climate Protection and Energy of the state of North Rhine-Westphalia decreed that "the generation of wind energy should also be possible on suitable forest areas in future."

?Tomorrow we'll worry about our thirst for water.“

"When it was announced that forests would now be open to wind energy, I swallowed more than ten times and asked, well, what does that mean for us in terms of tourism?" Maria Moritz is the non-party mayor of the 11,800-inhabitant municipality of M?hnesee, which surrounds the large artificial lake. Her fears quickly materialised. In December 2022, she receives a call from the mayor of the neighbouring municipality of Arnsberg, Ralf Paul Bittner. He tells her about the plans of wind power project developer Juwi GmbH. 35 wind turbines are to be built in the Arnsberg forest on land belonging to both municipalities. One half in Arnsberg, the other half near her in M?hnesee: "Then other project developers appeared, so that we would end up with almost 50 wind turbines, making it the largest area of wind turbines in a forest in Germany. And then a thought struck me: 'My God, what's going to happen to the soil in the forest?“

Lake M?hne is an important water reservoir for the Ruhr region. Its water level depends heavily on its surroundings. Healthy forest soils store water. If its surface area is reduced by construction, it is saturated more quickly during heavy rainfall. In times of drought, on the other hand, it could dry out more quickly. In the event of flooding or heavy rainfall, masses of water could flow directly into the River M?hne and even cause the dam wall of it to overflow, fears Moritz. This would be a disaster for the ?Ruhrverband“, the largest water management association in North Rhine-Westphalia. In the long term, Moritz believes it would also be a disaster for the people of M?hnesee, too: "We are worried about our hunger for energy today. And what about tomorrow? Tomorrow we'll worry about our thirst for water. Because the forest floor is the only really good natural substance for storing water that will gradually make water available to us.“

Soil was never an issue

The only thing she lacks is a scientific basis for her arguments. Up to now, debates about wind power have mainly centred on aesthetics, birds and protected areas. Soil has never been an issue. There are no studies on the effects of wind power on the forest ecosystem. Moritz finds this incomprehensible: "That's so typical of Germany. We just start off, but we don't think about the long-term consequences."

For her, hope comes from the current EU-wide research project KNOWING . Experts from Arnsberg want to analyse the effects of wind power on the forest ecosystem. Their findings should enable a compatible expansion of wind power. That would also suit Moritz, who is not fundamentally opposed to wind power: "I know we have to do something. I just want to make it tolerable."