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From siting to operation, wind project developers face a barrage of challenges. First, though regulations vary, you can't put a wind turbine within a certain distance of an area of national, historic or natural value. Also, unless residents are offered a share of the project, locals sometimes oppose them, citing aesthetic concerns.
So after a site is picked, there must be at least 12 months of study regarding controlled use of the space. In most places, bird and bat migratory patterns must be measured and observed before a permit can be issued, said Lorena Garcia, International Environment Department for Acciona Energia, Spain.
Garcia said her company has done post-construction studies of several of its sites. It found less than one bird mortality per year at its wind projects. Painting blades and installing LED lights as deterrents are ways developers try to prevent collisions.
Environmental concerns range from the popular debate over birds and bats to more subtle concerns like effects of transmission lines, construction vehicles, interference with low-flying planes, helicopters and interference with radar for airplanes and military.
Bats and birds are concerns environmental groups bring to the forefront in the fight against wind. But effects on humans also have some concerned as well.
Noise and shadow flicker can be disturbing, especially the closer the person's proximity to the wind turbine. Wind projects must comply with whatever the regulations are where the project is being built. Just as in the United States where regulations and permitting processes vary by state, within the European Union each member state has its own rules.
The standard for noise is usually no more than 55 decibels during the day and 45 decibels at night. As for visual impact on landscapes, in the industry there are three zones of visibility, said Jens Pouplier, Birk Nielsen, Denmark. The zone closest to the turbine, up to about 3 miles away, has the biggest impact on residents. To those in the middle zone, about 3 to 6 miles away, the turbines are still visible but they appear significantly smaller, he said. In the farthest zone, farther than 6 miles, the turbines should look like nothing more that dots on the horizon.
Visibility standards for offshore wind turbines are different. The closest turbines are about 11 to 21 miles from shore, then 21 to 35 miles and then very few farther than 35 miles from the coast.
"Wind farms should be integrated into the landscape so they have aesthetics of their own," Pouplier said. "We can't hide them, so we either have to accept them or not."
All of the major issues: bird and bat collision and mortality, landscape degradation, habitat displacement, shadow flicker, noise and others can be mitigated, Garcia said.
Projects are already delayed years by environmental impact studies; however, potential problems could be resolved with more careful avoidance of conservation areas, increased efforts to protect wildlife and local people, more enthusiastic post-construction monitoring, and having a biologist and ecologist on site from the beginning, Garcia said.
Also, she said, during construction and after, there are pre-emptive environmental steps that can be taken. Separating vegetative soil and moving it for agricultural use, using pre-existing roadways and paths and recovering the land's original profile are all ways the industry seeks to gain approval from environmentalists.
What has yet to be studied, however, is the cumulative impact of the wind farms. Each project does its own pre- and post-construction impact studies; however, there is no information on regional effects or global effects of the growing number of wind turbines.
Studies like that are hard to quantify, several officials said. There is so much variation among projects that it would be nearly impossible just to do such a study on one of the specific effects, such as bird mortality.
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