The placement of wind energy facilities (siting), as well as placement of individual turbines and project design within the project area, can offer opportunities to reduce collision risk for birds and bats, and avoid or minimize adverse habitat-based impacts for species of concern.
Micro-siting to reduce collision impacts for birds and bats
Wind developers use complex computer models to determine and refine the best location for individual turbines (micro-siting) based on factors like the wind resource, topography, and proximity to other turbines, as well as ecologically sensitive areas and other features of the landscape. Where pre-construction studies for a possible wind energy project indicate that species at risk of colliding with turbines are present or using the site, the project design phase offers developers an opportunity to consider how placement of turbines and other infrastructure can help minimize that risk.
Large raptors are known to take advantage of wind currents created by ridge tops, the upwind sides of slopes, and canyons that create wind patterns favorable to local and migratory movements. Siting individual turbines away from topographic features that attract concentrations of large raptors may reduce raptor collision fatalities at wind energy facilities.
Migratory bat activity may be influenced by landscape features such as land cover, topography, and the presence of water bodies. Variation in bat activity due to these features may be related to the observed variation in fatality rates among projects. However, some studies have found no relationship between bat fatality rates and landscape features, so more research is needed. Relating fatality rates to landscape features around a wind energy facility could help avoid higher-risk areas during the project design phase.
Learn more in AWWI’s Summary of Wind Power Interactions with Wildlife.
Siting to avoid or minimize habitat-based impacts
For the majority of species listed under the federal Endangered Species Act, the primary reason for their protected status is habitat loss and fragmentation. The best opportunity to avoid habitat-based impacts from wind energy is to site wind facilities on land that has already been transformed by compatible human activities like agriculture, ranching, oil and gas development, or surface mining.
At the macro level, wind developers can make efforts to avoid landscapes that offer high-quality habitat for species of concern. However, there are many constraints developers consider when siting a wind project that can limit where a project can be built. Even in cases where the overall project footprint includes intact habitat for a species, it may still be beneficial to place turbine pads and other infrastructure on already disturbed parcels if possible. Project design can also consider maximizing use of existing roads, which can minimize the need for any additional fragmentation of the project area.
Studies of prairie grouse and grassland bird responses to wind turbines, roads, and other infrastructure often attempt to quantify impacts as a function of distance from the source of impact and the habitat in question such as leks (mating ground) or nesting sites. The U.S. Geological Survey has compiled and summarized scientific studies evaluating the influence of anthropogenic activities and infrastructure on greater sage-grouse, providing a reference for biologically relevant and socioeconomically practical buffer distances around sage-grouse habitats.
Developers can consult with state wildlife agencies for advice about the location of sensitive habitat and any specific sensitivities of local species of concern: noise, tall structures that provide perching opportunities for predators, human activity, or roads and vehicle traffic. In addition to site design, the timing of construction work and routine facility operations and maintenance can also be scheduled to avoid seasons and times when it would be most detrimental to key lifecycle activities, such as mating and nesting.
U.S. Fish & Wildlife Service Recommendations
Chapter 7 of the U.S. Fish and Wildlife Service Land-Based Wind Energy Guidelines recommends using available data (including results of pre-construction studies) when establishing the layout of turbines as well as roads, power lines, fences and other infrastructure. This may include establishing non-disturbance buffer zones to protect sensitive habitats or areas of high risk for species of concern identified in pre-construction studies. It can also include locating turbines to avoid separating bird and bat species of concern from their daily roosting, feeding, or nesting sites if it is documented that the turbines’ presence poses a risk to species.