Mining for coal, fracking for gas and drilling for oil have all becoming increasingly synonymous with environmental action, protest and confrontation. But renewables can also be highly contentious — even among the eco-minded.

Speaking about plans to clear an area of forest near her home in order to create space for wind turbines, Gabriele Niehaus-Uebel said she feels "powerless, helpless and angry." She chairs a citizen initiative that opposes the 20-turbine wind farm in Germany's central region of Hesse.

Though the planned facility would affect less than 2% of the forest, Niehaus-Uebel says "a previously intact ecosystem would be destroyed."  She compares it to the iconic Hambach forest which is under threat from the expansion of a lignite mine.

"There, they are fighting for every single tree, and it's made public in the press," Niehaus-Uebel told DW, adding that not a word is spoken about her local woodland earmarked for clearance.

The discussion, however, isn't new.

"There has been opposition to wind energy since the very beginning," Stefan Gsänger, secretary general of the World Wind Energy Association (WWEA), told DW. "That's part of every democratic transformation."

Niehaus-Uebel's group is just one of around 1,000 actively opposed to wind power projects in Germany, an activist website shows.

Yet wind energy is a part of the puzzle to meet global energy demand — which is expected to increase by 30% within the next two decades — while slowing down climate change.

According to the WWEA , wind turbines installed by end of 2018 will account for close to 6% of global electricity demand.  The total share of renewable energy in the power sector is expected to increase from 25% in 2017 to 85% by 2050, mostly through growth in the solar and wind sectors, the International Renewable Energy Agency says.

As this shift continues, understanding the impact of wind farms on nature is essential.

Birds, bats and blades

Wind turbines are often citied as being particularly bad for birds and bats. Birds of prey, for instance,  have a blind spot in front of them, and look down as they search for food. Collision with unseen giant blades can easily prove fatal. The towering structures can also force birds to deviate from their regular routes between breeding and feeding areas, meaning they have to travel longer distances which can ultimately leave them with less energy to raise young.

Poor planning in places such as Extremadura, in southern Spain, has led to wind farms being built in biodiversity hotspots or close to them. A report by the Spanish conservation group SEO BirdLife says this could increase the pressure on threatened species such as the Spanish imperial eagle. 

But numerous other studies have shown that bird deaths caused by wind turbines are much lower than other human-related causes such as power lines or collisions with buildings. 

SEO BirdLife's report, however, highlights flaws in such studies, including a lack of information and small sample sizes, and is calling for further research.

"Neither should we lose sight of the fact that even small fatality rates might have a critical effect for threatened species or those with a very low rate of breeding success," the group stated in its report.

Mark Harthun, head of nature conservation with NABU Hesse, says that in a climate emergency context, using woodland potential for renewable energy is "the best protection for forests and for all species living in there." Adding that the last two dry summers have damaged 15,000 hectares of forest in the region of Hesse.

Nonetheless, NABU has filed several of its own complaints against other wind energy projects in Germany, which it says could put nature at risk. Harthun describes them as "exemplary complaints" to encourage greater risk assessment. 

Further afield

Outside Europe, BirdLife South Africa recently celebrated a decision to stop a planned wind farm in the Groot Winterhoekberg mountains, about 120 kilometers (about 75 miles) north of Cape Town, that could have threatened endangered birds. The group coordinates the Energy Task Force, established by the UN Convention on Migratory Species, to identify locations where renewable energy structures can be built without harming birds. 

Alex Lenferna, social justice campaigner for 350Africa, agrees that ecological concerns related to wind turbines must be taken into account, but also highlights the broader context of the transition.

"In places like South Africa, where coal is very prevalent, the transition to renewable energy is much more beneficial ecologically than continuous reliance on fossil fuels," he told DW. 

In most cases, adequate siting and technological improvements can avoid wind turbines conflicting with biodiversity, experts agree. Selective shutdown of turbines in sensitive areas for migratory birds, for instance, can be very effective.

A 2012 study published in the journal Biological Conservation recorded a 50% drop in vulture fatality rates at 13 wind farms in Cádiz, southern Spain, after they began turning off their turbines when the birds were observed nearby. Energy production fell by just 0.7% per year.

The American Wind Wildlife Institute examined ten separate studies related to bird fatalities as a result of wind turbines and concluded that restricting blade rotation at low wind speeds could reduce the number of bat fatalities by between 50 and 87%. 

Involve people

Although not every wind turbine will be built, and not every bird and bat will survive those that do go up along the road to cleaner energy, experts say acceptance increases if local people are involved.

"The key to all of this is to involve all these affected people as much as possible and allow as much ownership and benefit as possible from the beginning," Gsänger said. 

That's also a big issue in the South African context, Lenferna said, suggesting a move "away from a more privatized model, which tends to favor big corporations and multinationals, to thinking about how do we make ownership something that is more in the hands of South african communities." 

In developing countries such as Mali, renewable energy is key to escaping poverty, and ownership could be a game changer, Gsänger pointed out. "People would not only have energy, but also control over it."

On this point, wind farm supporter Gsänger and opponent Niehaus-Uebel agree: Citizen participation and ownership would reduce the overall impacts of wind energy, because they understand and value the land more than anyone else. 

Wind turbines will mostly impact local people, Niehaus-Uebel said, and therefore, "it's not up to politicians in other cities that don't know the area to decide." Decentralized power supply options are essential, she added, including small private wind turbines installed at home.