Wind Energy Projects and Safety
As a source of abundant energy, wind energy offers many advantages. However, as with any energy generation facility, those who live and work near wind energy facilities may have concerns about how these facilities impact human health and safety.
Fortunately, wind turbines have an excellent record of safety, and a significant body of research indicates that there is no direct relationship between human exposure to wind turbines and human health issues. Wind energy project developers and operators also take to minimize health and safety impacts to the communities that host them as well as establish and meet safety standards for the wind energy workforce.
Do Wind Turbines Cause Health Issues?
Although concerns about potential impacts on human health from neighboring wind turbines are often topics of discussion when new wind energy projects are proposed, a wide body of scientific evidence suggests no direct relationship between human exposure to wind turbines and human health issues.
Neighbors may express concerns about impacts on their community, such as noise and shadow flicker. However, wind turbine noise remain far below levels that risk hearing damage—only slightly louder than a whisper—at a standard distance. And shadow flicker is rare and should not have medical impacts, requiring specific lighting situations and occurring at a frequency well below the threshold known to trigger photosensitive epilepsy symptoms.
People living near wind energy projects may also express concerns about wind turbines emitting radiation or electromagnetic field (EMF) exposure from wind turbines.
However, field measurements show EMF levels near wind turbines are well below any existing regulatory guidelines with respect to human health and are, in fact, lower than those produced by many common household electrical devices, such as microwave ovens, computers, and wireless internet routers.
Are Wind Turbines and Wind Farms Safe?
Wind turbines have an excellent safety record; however, as with any type of machinery, turbines can fail and cause safety risks that should be taken seriously.
Turbine failures are considered rare events with fewer than 40 incidents identified in the modern fleet of more than 40,000 turbines installed in the United States as of 2014.
Can Wind Turbine Blades Detach From a Turbine?
A blade throw—a failure in which a turbine blade detaches mid-operation—is virtually impossible with modern turbines due to improved engineering and the use of hazard sensors.
Although this type of failure was a concern in the early years of the wind energy industry, modern wind energy farms are reliable, safe, state-of-the-art power plants with well-tested technologies that meet approved standards and hundreds of thousands of hours of operating experience.
Can Wind Turbines Break in High Winds, Like Tornadoes?
Typically, wind turbine designs are subjected to rigorous testing before production, which includes component testing and testing the full turbine. Many factilities and federal programs support wind turbine testing, and research continues to improve technology resilience and safety to extreme conditions, such as high winds.
Wind turbines are required to be placed a minimum distance from inhabited buildings (known as a setback ordinance) in order to reduce risk to human safety in the unlikely case of a catastrophic event. (For additional safety information, see section 2.8 of the 2021 land-based wind energy siting report.)
Ice buildup on the Cascade Engineering SWIFT wind turbine rotor at the National Renewable Energy Laboratory’s Flatirons Campus results in an automatic shutdown to prevent ice shedding. Graphic by Ismael Mendoza, National Renewable Energy Laboratory
Although wind turbines are designed to automatically shut off at very high wind speeds, they—like any other piece of infrastructure including buildings—can be damaged by a direct hit by a tornado. One advantage that renewable energy sources like wind have over more centralized power plants (like coal or natural gas) is their distributed nature; if one or several wind turbines are damaged, the other turbines in the wind plant can keep operating and providing power.
Do Wind Turbines Have to Be De-Iced?
Under certain conditions, ice can accumulate on wind turbine blades and slide off during operation in a process called ice shedding.
Anti-icing and de-icing technologies can reduce the risk of ice accumulation, allowing modern wind turbines to operate at temperatures as low as -40°C. These cold-weather packages can include special blade coatings to prevent icing. Strategically placed thermostat-controlled resistive elements or forced-air heaters can heat instruments and operating components during cold weather conditions to prevent ice formation.
If severe ice buildup occurs during operation, turbines may automatically shut down until the conditions improve. As another precautionary measure, operators will use defined start-up procedures after icing events. To lower the risk of damage or harm, wind farm developers ensure wind turbines are adequately spaced apart from each other and any nearby residences to avoid risk of damage or harm (read more about this below).
Does Lightning Strike Wind Turbines?
Being as tall as 100 meters (or taller), wind turbines attract lightning, which tends to strike conductive materials (like metals) in an attempt to take the fastest route to the ground.
Researchers use lightning simulation techniques to see where lightning might strike a wind turbine blade to improve lightning protecttion systems. The researchers in this 2021 study, which used the National Renewable Energy Laboratory's wind turbine testing facilities, noticed the tip of the blade or one of the edges typically took the electrical hits; The inside of the blade or welded seams were spared, which would preventing too much damage to the turbine. Photo from , National Renewable Energy Laboratory
Wind turbine blades typically contain lightning protection systems that redirects the energy of a lightning strike to avoid it harming a wind turbine’s structure or affecting its operation. Researchers continue to test and improve these systems and work to make them out of increasingly recyclable materials.
How Do Developers and Owners Ensure the Safety of Wind Energy Projects?
Although unlikely, developers help prevent potential safety risks—such as blade icing, ice shedding, and blade throws—during installation by placing turbines so that they face away from inhabited structures.
During operation, owners and operators ensure that turbines are properly maintained or removed if no longer functioning.
Technicians who service wind energy technologies receive proper training and education. Industry-based guidance documents, such as the American Clean Power Association’s Offshore Compliance Recommended Practices, provide standards to improve worker safety. Read our resource on offshore wind energy workforce safety.
What Safety Certifications Exist for Small Wind Turbines?
For wind turbines under 100 kilowatts, purchasing a model that has been certified to performance and safety standards is the best way to ensure safe operation. The Small Wind Certification Council, UL, and other entities provide accredited, third-party verification for safety, performance, and durability of small wind turbines. The Clean Energy States Alliance maintains a unified list of certified wind turbines.