This page points out the threats to animals (mostly birds and bats) due to wind power production. The following articles deal with avain and bat fatalities as a result of wind power production. With the main focus on global climate change and reducing nonrenewable energy, I feel this is an often overlooked problem with jumping on board with such renewable resources. However, I am on board with renewable energy all the way (as I am sure all fo you are), but this switch over is not just full of benefits. There are costs to this process as well.
Hopefully this will provide some insight into the negative impacts of wind turbines on wildlife and maybe some considerations for some of you who will be making such decisions on where to put turbines someday.
Avain and Bat Fatalities at Old-Generation and Repowered Wind Turbines in California
Smallwood, K.S. and Karas, B.
Journal of wildlife Management, September 2009
Wind turbines in the Altamont Pass Wind Resource Area (APWRA), California, USA, have caused annual fatalities of thousands of raptors and other birds. Alameda County implemented an Avian Protection Program requiring mitigation measures and eventual repowering to modern wind turbines, all intended to reduce raptor fatality rates 50% from levels estimated for 1998–2003. Two years into the 3-year program, we compared estimates of fatality rates between 1998–2003 and 2005–2007 and between a repowered wind project (Diablo Winds) and the APWRA's old-generation wind turbines. The APWRA-wide fatality rates increased significantly for multiple bird species, including 85% for all raptors and 51% for all birds. Fatality rates caused by the Diablo Winds repowering project were not lower than replaced turbines, but they were 54% and 66% lower for raptors and all birds, respectively, than those of concurrently operating old-generation turbines in 2005–2007. Because new-generation turbines can generate nearly 3 times the energy per megawatt of rated capacity compared to the APWRA's old turbines, repowering the APWRA could reduce mean annual fatality rates by 54% for raptors and 65% for all birds, while more than doubling annual wind-energy generation. Alternatively, the nameplate capacity of a repowered APWRA could be restricted to 209 megawatts to meet current energy generation (about 700 gigawatt-hr), thereby reducing mean annual fatalities by 83% for raptors and 87% for all birds. In lieu of repowering, bird fatalities could be reduced by enforcing operating permits and environmental laws and by the County requiring implementation of the Alameda County Scientific Review Committee's recommendations.
This article calls for the repowerment of old-generation turbines with new ones asap in order to reduce avain deaths releated to turbines and these new-generation turbines are far more efficient than the old ones (a win-win situation?). Lack of environmental law enforcement also seems to be a large issue.
A Large-Scale Mitigation Experiment to Reduce Bat Fatalities at Wind Energy Facilities
Baerwald et al.
Journal of Wildlife Management, Sept., 2009
Until large numbers of bat fatalities began to be reported at certain North American wind energy facilities, wildlife concerns regarding wind energy focused primarily on bird fatalities. Due in part to mitigation to reduce bird fatalities, bat fatalities now outnumber those of birds. To test one mitigation option aimed at reducing bat fatalities at wind energy facilities, we altered the operational parameters of 21 turbines at a site with high bat fatalities in southwestern Alberta, Canada, during the peak fatality period. By altering when turbine rotors begin turning in low winds, either by changing the wind-speed trigger at which the turbine rotors are allowed to begin turning or by altering blade angles to reduce rotor speed, blades were near motionless in low wind speeds, which resulted in a significant reduction in bat fatalities (by 60.0% or 57.5%, respectively). Although these are promising mitigation techniques, further experiments are needed to assess costs and benefits at other locations.
Don't forget about the bats! Large scale wind turbine increases have occured throughout the world, with the U.S. and Canada increasing wind power generation by 45% and 26% respectively in 2007 alone. This growth is due to the view of renewable energy resources being viewed as environmentally friendly alternatives to fossil fuels (which they are), but there are always tradeoffs.
Influence of Behavior on Bird Mortality in Wind Energy Developments
Smallwood, K.S., Rugge, L., and Morrison, M.L.
Journal of Wildlife Management, Sept., 2009
As wind power generation is rapidly expanding worldwide, there is a need to understand whether and how preconstruction surveys can be used to predict impacts and to place turbines to minimize impacts to birds. Wind turbines in the 165-km2 Altamont Pass Wind Resource Area (APWRA), California, USA, cause thousands of bird fatalities annually, including hundreds of raptors. To test whether avian fatality rates related to rates of utilization and specific behaviors within the APWRA, from March 1998 to April 2000 we performed 1,959 30-minute behavior observation sessions (360° visual scans using binoculars) among 28 nonoverlapping plots varying from 23 ha to 165 ha in area and including 10-67 turbines per plot, totaling 1,165 turbines. Activity levels were highly seasonal and species specific. Only 1% of perch time was on towers of operating turbines, but 22% was on towers of turbines broken, missing, or not operating. Of those species that most often flew through the rotor zone, fatality rates were high for some (e.g., 0.357 deaths/megawatt of rated capacity [MW]/yr for red-tailed hawk [Buteo jamaicensis] and 0.522 deaths/MW/yr for American kestrel [Falco sparverius]) and low for others (e.g., 0.060 deaths/MW/yr for common raven [Corvus corax] and 0.012 deaths/MW/yr for turkey vulture [Cathartes aura]), indicating specific behaviors or visual acuity differentiated these species by susceptibility to collision. Fatality rates did not correlate with utilization rates measured among wind turbine rows or plots for any species except burrowing owl (Athene cunicularia) and mallard (Anas platyrhynchos). However, mean monthly fatality rates of red-tailed hawks increased with mean monthly utilization rates (r2 = 0.67) and especially with mean monthly flights through turbine rows (r2 = 0.92). Fatality rates increased linearly with rates of utilization (r2 = 0.99) and flights near rotor zones (r2 = 1.00) for large raptor species and with rates of perching (r2 = 0.13) and close flights (r2 = 0.77) for small non-raptor species. Fatalities could be minimized or reduced by shutting down turbines during ≥ 1 season or in very strong winds or by leaving sufficiently large areas within a wind farm free of wind turbines to enable safer foraging and travel by birds.
Raptors are particularly at risk. Smallwood et al. hypothesized that these birds in particular loose track of wind turbines while focusing on diving for prey, fly-catching prey and hovering. This hypothesis was not refuted by the results of the study. They also used data to come up with models to estimate the amount of bird kills per year due to turbines based on bird size and bird appearance rates.
Final summarry: Know where to put those turbines, they are great but have unseen impacts usually.