energy
Wind Energy
Wind power is an important part of our clean energy solution. However, proper siting of wind farms is key.
Montana Audubon is working to ensure that wind energy producers do not locate their farms in critical habitat for birds or other wildlife. The problem with wind farms is straightforward: if farms are located in areas heavily used by birds, such as in a migration flyway or on a nesting area for a rare or species, lots of birds are unnecessarily killed each year. However, if these areas are avoided, bird deaths are not a problem.
March 2012: Interested in Kevin Rim, an Important Bird Area (IBA) threatened by the Rim Rock wind farm? Head here.
To guide us in our work, Montana Audubon has adopted a Wind Energy Siting Policy Guidance Document.
Wind is Coming to Montana:
Montana ranks #1 for class 3 or better wind. Because of our rich wind resource, wind farms are being planned throughout the state. Because wind farms do not require permits in Montana, it is difficult to track what farms are being built where. However, based on several sources, we have pieced together the following map of developed and proposed commercial wind projects:
To download this map as a pdf, click HERE.
Impacts to Montana Wildlife
There are two basic ways that wind turbines impact wildlife: through turbine collisions/contact and through fragmentation of habitat. What we know in Montana about the impacts on wildlife is summarized below.
For more information about documented impacts of wind energy on birds and bats, click HERE.
Bird Collisions with Wind Turbines:
Since most birds migrate at night, they are vulnerable to colliding with structures such as wind turbine. This is especially true when weather events force birds to fly at lower elevations.
In Montana, studies at Judith Gap Wind Farm indicate that there are fatalities between 3.3 - 4.5 birds per turbine per year. Environmental studies done prior to construction of this wind farm predicted these bird fatality rates. This rate is considered acceptable for a wind farm project because it will not impact bird populations.
The good news about newer wind turbines is that they don’t have places for birds to perch or nest: newer turbines do NOT have lattice areas for birds to perch; in addition, transmission lines between turbines are almost always underground. Fewer birds using turbines and power lines and poles, means fewer birds strike turbines. This is especially true in the prairie, where perches are particularly attractive to everything from meadowlarks to raptors. Since this design change, the number of birds killed by wind turbines has decreased significantly.
Bats and Wind Turbines:
There are at least two ways that bats are killed by wind turbines. First, since most bats migrate at night, they are vulnerable to colliding with structures such as wind turbine. Secondly, bats may be attracted to the moving blade of the wind turbine. This attraction can spell trouble: if bats get too close to the turbine blade, they are sucked into the lower pressure area following the blade. This low pressure area expands their lungs, causing them to die from barotrauma. For more information on barotrauma, click HERE. Specifically in Montana:
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Studies at Judith Gap Wind Farm indicate that there are fatalities between 7 – 13 bats per turbine per year. Environmental studies done prior to construction of this wind farm only predicted 4 bats per turbine per year. Consequently, the bat fatality rates werehigher than expected.
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Migratory tree roosting bats were the most common bats killed by turbines at Judith Gap. Specifically, most of the bats found under turbines were hoary bats (Lasiurus cinereus) or silver-haired bats (Lasionycteris noctivagans), which is pictured above (photo by Kristi DuBois). These batswere killed during their August to September migration south.
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In other states, Eastern Red Bat (Lasiurus borealis), which are also found in Montana, are commonly found to be vulnerable to wind turbine mortality.
Habitat Fragmentation:
Habitat fragmentation occurs when wind farms—and their associated roads, power lines, and other structures—displace wildlife (see photo on right). The impacts of habitat fragmentation go far beyond the immediate “footprint” of the wind farm, because some wildlife—particularly prairie species—will avoid areas with high towers. The solution? Keep wind farms close to established roads, cropland, and other developed areas—and away from large blocks of crucial wildlife habitat.
Commercial wind farms in Montana use between 20 acres (Two Dot) and 50,000 acres (Glacier Wind Farm near Shelby).
How Does Montana Regulate Wind Farms?
Currently Montana has virtually no ability to regulate wind farms. Consequently, wildlife concerns may only be addressed if a wind farm is located on public land. When this happens, an environmental review must be conducted under either the Montana Environmental Policy Act (MEPA) for state land, or under the National Environmental Policy Act (NEPA) for federal land (forest service, BLM, etc.). These environmental reviews usually allow the public to comment on the proposed project.
Modern Wind Turbine Technology:
Modern wind turbines are getting more efficient than their predecessors—and quite a bit bigger in size.
The new wind turbines generally used at Montana wind farms produce about 1.5 Megawatts (MW) of energy. In general, these 1.5 MW turbines are:
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Height of Tower: 250 – 300 feet;
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Blade Length: 100 – 130 feet;
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Total Height of Turbines: 390 – 400 feet;
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Wind Speeds Used by Turbines: Wind turbines usually start spinning when the wind is stronger than 6 - 7 miles per hour (mph); they stop spinning when wind speed go above ~ 50 mph.
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Speed of Turbines: The tips of the blades can spin as fast as 230 mph.
The good news about these newer turbines is that they don’t have lattice areas for birds to perch and transmission lines between turbines are almost always underground. These two design improvements have reduced the number of birds killed by wind turbines significantly. Larger turbines are being used elsewhere.
Larger turbines are currently being used in other states.
Learn More about Wind Energy: 
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In 2009, The Nature Conservancy completed An Ecological Risk Assessment of Wind Energy Development in Montana - an excellent report (14.3 MB).
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The bat mystery has been confounding biologists. Finally some answers as to why bats are particularly susceptible to deaths at wind farms - it's called "barotrauma" - read more here.
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Assessing Impacts of Wind-Energy Development on Nocturnally Active Birds and Bats: A Guidance Document. Journal of Wildlife Management. 2007 (PDF, 1 MB).
- Estimating Wind Turbine–Caused Bird Mortality. Journal of Wildlife Management. 2007
- Impact of Wind Energy and Related Human Activities on Grassland and Shrub-steppe Birds: A Literature Review. Prepared for the National Wind Coordinating Collaborative by the Ornithological Council. October 2007.
- Wind Energy Development and Wildlife Conservation: Challenges and Opportunities. Journal of Wildlife Management. 2007
National Audubon Society and NRDC have created MAPS of restricted lands and sensitive wildlife areas in the western US, to help plan energy development projects by avoiding key areas. View sensitive areas in Montana - go to Google Earth Outreach >>