FARGO — Wind farms are hailed as a source of clean, renewable energy. But even wind energy supporters acknowledge that those spinning wind turbine blades impose an environmental cost: dead birds.
Consequently, federal wildlife officials are mulling a morbid question involving a large North Dakota wind farm: How many bald eagle deaths do they consider acceptable for a bird that is legally protected and hallowed as a national symbol?
Their tentative answer: About one per year, or up to five dead bald eagles over a five-year permit period.
That's a key provision of a draft environmental assessment for a bald eagle taking permit for the
Courtenay Wind Farm north of Jamestown, N.D., which would allow up to five protected bald eagles to be "incidentally" killed over five years.
The permit under consideration by the U.S. Fish and Wildlife Service acknowledges that birds, including bald eagles, sometimes are killed when they collide with wind turbines, are electrocuted by high-voltage power lines, or suffer breeding productivity losses through habitat destruction resulting from wind farms.
The Courtenay Wind Farm's number of allowable bald eagle deaths was computed after surveys and observations of the site, including before it was built, and based on published research, Smith said.
If the number of bald eagle deaths exceeds the number allowed, wildlife officials will work with the wind farm's company to find ways to reduce risks, he said.
Courtenay Wind Farm, which has been operating since 2016 about 15 miles north of Jamestown in Stutsman County, is located within an area where bald eagles are known to nest and fly through, according to the draft environmental assessment by the U.S. Fish and Wildlife Service evaluating the permit.
The draft permit for Courtenay Wind Farm is the first to be reviewed in North Dakota. The bald eagle taking permits are a recent regulatory tool, and so far only a few have been issued around the country, including two in California and one expected to be issued soon in Wyoming, said Brian Smith, the wildlife service's chief of the migratory bird for a western region that includes North Dakota.
"We encourage it," he said of the permits and the conservation collaborations they generate with wind energy firms. "It's completely voluntary on the company's part."
Although there are more than a thousand migratory birds, so far the taking permits have been applied only to bald eagles and golden eagles, the only bird species protected under two federal laws, Smith said. "They have a higher conservation bar for those two species."
Owned by Xcel Energy, Courtenay Wind Farm's 100 turbines are capable of generating up to 100 megawatts of electricity, enough to power about 105,000 homes. The wind farm sprawls over almost 25,000 acres in east-central North Dakota.
The height to the tip of the highest blade of each turbine is 426 feet, according to Xcel. One dead bald eagle was found near a turbine last summer and was sent to a federal lab in Oregon for a necropsy, but results still are pending.
The wind farm's original design was modified to try to reduce bald eagle deaths. Changes included removing nine turbines from the project's layout after eagles were observed using the areas, reducing the risk of collision.
Electricity collected from each turbine is carried by underground power lines connected to a substation. Burying the lines avoids the risk of eagle collision or electrocution. Also, Courtenay Wind Farm has a buffer of at least one mile around all known bald eagle nests to avoid unintended deaths, a step recommended by wildlife officials.
"We've developed wind projects to provide our customers low-cost energy and significant environmental benefits," Randy Fordice, an Xcel Energy spokesman, said in a statement. "As with all development, we do it responsibly. We fully understand and appreciate concerns around wind turbines and wildlife, and follow best practices to protect eagles and other wildlife near our wind farms."
Wildlife service officials hope to conclude their review of the permit for Courtenay Wind Farm by the end of the year, Smith said.
Bald eagles are protected under federal law, but since 2007 have not been considered endangered or threatened.
Bald eagles nest sparsely in eastern North Dakota, and typically are found near large bodies of water.
In 2009, wildlife officials estimated there were 67 occupied bald eagle nests in the state. Since then, however, the number of bald eagle nests has soared, with an estimated 165 as of 2015.
Studies have shown that all forms of energy development kill birds in unintended ways, and some studies suggest oil development is more lethal than wind turbines-but some researchers have concluded that cats kill far more birds than all forms of energy development combined.
What: Public comments are being accepted by federal wildlife officials on a draft permit to allow the "taking" of bald eagles by the Courtenay Wind Farm north of Jamestown, N.D.
When: Comments accepted until Monday, June 18, 2018
How to submit comments: Email: FW6WindEnergyCourtenay Wind Farm DEA, U.S. Fish and Wildlife Service, Mountain-Prairie Region, Attention: Hillary White, P.O. Box 25486 DFC, Denver, CO 80225
More info: Documents can be viewed online at https://www.fws.gov/mountain-prairie/wind/