In this section of wind energy basics, the concerns that are sometimes expressed relating to wind energy development will be addressed.
Wind energy is competitive with conventional energy sources such as coal and nuclear power. To build a NEW power plant, wind is the 2nd most cost effective (1st is natural gas, which is a non-renewable resource). Integrating wind energy into the current electricity production schemes and integrating with existing utilities hedges against electricity price volatility. The technology is also continually improving to make turbines more efficient, which also reduces the cost of deployment.
Wind is an intermittent resource, but it is reliably intermittent. This means that wind and windy episodes can be predicted. Changes in electricity generation with wind energy are more gradual and predictable. Loads can be predicted and thus generation demands; operators are accustomed to balancing electricity need and demand.
The aesthetic qualities of a wind turbine can vary depending on the observer. Some see them as an eyesore, where some people see them as a sign of the future. Some see turbines as disrupting the landscape and others see them as elegant machines. It is a personal issue but one that affects wind energy deployment nonetheless. If someone is concerned with how a turbine may impact their viewshed or landscape, the best thing to do is to go see an operational turbine and see what it looks. Then ask, would I rather look at a new coal or natural gas generation facility? Do I want to keep my lights and refrigerator on?
Wind turbines do produce sound when in operation. When sited properly, the sound should not significantly impact nearby properties. The figure below depicts decibel ratings at increasing distances from a turbine with other electronics/machinery for reference.
There has been some concerns surrounding “wind turbine syndrome,” which is defined as the disruption or abnormal stimulation of the inner ear's vestibular system by turbine infrasound and low-frequency noise, the most distinctive feature of which is a group of symptoms called visceral vibratory vestibular disturbance
In 2009 the American Wind Energy Association (AWEA) convened a scientific advisory panel of doctors, audiologists, and acoustical professionals to study the perceived health effects of wind turbines. The advisory panel concluded that based on the levels and frequencies of turbine sounds, they found no reason to believe that turbines could plausibly have direct adverse physiological effects.
Shadow flicker is caused when rotating wind turbine blades periodically cast shadows through constrained openings such as the windows of neighboring properties. It is much less common in the United States than in Europe due to the lower latitudes and the higher sun angles in the U.S. Shadow flicker can be modeled and planned for when developing projects. Modeling of the sun angles and location of surrounding properties can be used to mitigate issue. The concern surrounding shadow flicker is that it can cause epileptic seizures but also that it is just an annoyance. Studies have been conducted that indicate the frequency of the flickering caused by the wind turbine rotation is such that it should not cause a significant risk to health. The strobe rates generally necessary to cause seizures in people with photosensitive epilepsy are 5 to 30 flashes per second and large wind turbine blades cannot rotate this quickly. Residential turbines do not have blades long enough to cause a significant shadow flicker in homes. The duration of flicker, if it is experienced, would also be for a short amount of time during sunrise or sunset when the sun is lowest in the sky.
Another common concern is related to the impact that wind energy developments will have on surrounding property values. A study done by the Berkley Laboratory called The Impact of Wind Power Projects on Residential Property Values in the United States: A Multi-Site Hedonic Analysis, examined 7,500 sales of single-family homes situated within ten miles of 24 existing wind facilities in nine different U.S. states. Conclusions were drawn from eight different pricing models; the analysis from eight models all consistent- there is no conclusive evidence of the existence of any widespread property value impacts in communities surrounding wind energy facilities.
“Neither the view of wind energy facilities nor the distance of the home to those facilities was found to have any consistent, measurable, and significant effect on the selling prices of nearby homes.”
This doesn’t necessarily mean that wind development couldn’t negatively impact property values but if they do, the impacts are likely to occur infrequently.
Another concern related to wind turbines is that they will catch on fire. This generally only occurs if the braking function inside the nacelle is not working correctly. Turbines have regular maintenance schedules which are maintained by trained technicians that service the turbines regularly. The other possible cause of a turbine catching fire is a lightning strike, which is not a common occurrence because the turbines are grounded, just like cell towers or any other tall structure.
In higher latitudes that get a lot of snow and ice, some people can be concerned that a wind turbine will throw ice from the blades. Because turbine blades rotate based on the principle of lift, it is highly unlikely that they would even be able to rotate if they are covered in ice. The ice that may cover the blades results in a shape that is not aerodynamically conducive to create lift, even in strong winds. Ice accumulations can occur, however, but the ice will slide or drop off the blades as temperatures warm and the ice melts. Another reason that ice throw is highly unlikely is that if there is a dangerous snow or ice storm forecasted, turbine operation will commonly cease, as the facility managers don’t want to damage the electronics or structure of the turbine.
A common concern relating to wind energy development is that the construction impacts (of a large scale facility or wind farm) will negatively impact the surrounding area. Generally speaking, developers want to make as little impact as possible and engage in as little construction as possible because more construction adds costs to a project. Abandoned coal mines, landfills, or brownfields can be used as sites for wind farms, making them useful again. These sites can be great for wind farms because they are likely to have less conflict of land use than a mountain top, for instance. The creation or expansion of roadways, noise during construction, and wildlife aversion to construction area are all issues that have requirements or criteria that must be met by the developer in the permitting process. For every wind project in the U.S., there is a permitting process that must be followed, including an Environmental Impact Assessment (EIA). More information about permitting specific to Virginia can be found through the Virginia Department of Environmental Quality.
During construction of a wind facility, there are positive impacts to a region also. An area near wind farm development often see increased economic benefits because construction workers need places to stay, eat, and refill supplies. Developers will also try to use as many locally-sourced products as possible because it will be less expensive to the overall cost of a project.
The decommissioning process has minimal impact to the surrounding area since the roads and infrastructure are already in place. Provisions and plans for the decommission of a large-scale wind facility is a criteria that is required in the permitting agreement.
There is a common concern of the impact wind turbines have on birds. This concern is generally only applicable for large-scale turbines. It is important to consider the kind of birds that will be impacted as well. Environmental Impact Assessments must be completed prior to project permitting to determine the potential impacts on all wildlife, including birds and bats. The American Wind Energy Association has more information about birds and wind energy.
Similar concerns with birds are also applicable to bats. The American Wind Energy Association has more information about bats and wind turbines.
Much research has been done on the impact of wildlife and habitat impacts relating to wind energy. The American Wind Energy Association has more information about wildlife and habitat impacts.
Every kWh that comes from wind energy doesn’t come from coal, oil, or natural gas, offsetting pollution that would have been generated from those sources. Electricity generation from wind power doesn’t produce heat or gases that contribute to the greenhouse effect: