What is noise? "Noise," when one is talking about wind energy projects, basically means "any unwanted sound." Whether a noise is objectionable will vary depending on its type (tonal, broadband, low-frequency, impulsive, etc.) and the circumstances and sensitivity of the individual who hears it (often referred to as the "receptor"). As with beauty, often said to be "in the eye of the beholder," the degree to which a noise is bothersome or annoying is largely in the ear of the hearer. What may be a soothing and relaxing rhythmic swishing sound to one person may be quite troublesome to another. Because of this, there is no completely satisfactory and See details

What kinds of noise do wind turbines produce?
Wind turbines most commonly produce some broadband noise as their revolving rotor blades encounter turbulence in the passing air. Broadband noise is usually described as a "swishing" or "whooshing" sound. Some wind turbines (usually older ones) can also produce tonal sounds (a "hum" or "whine" at a steady pitch). This can be caused by mechanical components or, less commonly, by unusual wind currents interacting with turbine parts. This problem has been nearly eliminated in modern turbine design. See details

How noisy wind farms are? Good question, and a difficult one.
Wind plants are very, very quiet compared to other types of industrial facilities, such as manufacturing plants, but most industrial plants are not located in rural or low-density residential areas. In those types of areas, background noise tends to be lower than in urban areas.
On the other hand, wind plants are always located where the wind speed is higher than average, and the "background" noise of the wind tends to "mask" any sounds that might be produced by operating wind turbines—especially because the turbines only run when the wind is blowing. The only occasional exception to this general rule occurs when See details

What have manufacturers done to reduce wind turbine noise? Most rotors are upwind: A wind turbine can be either "upwind" (that is, where the rotor faces into the wind) or "downwind" (where the rotor faces away from the wind). A downwind design offers some engineering advantages, but when a rotor blade passes the "wind shadow" of the tower as the rotor revolves, it tends to produce an "impulsive" or thumping sound that can be annoying. Today, almost all of the commercial wind machines on the market are upwind designs, and the few that are downwind have incorporated design features aimed at reducing impulsive noise (for example, positioning the rotor so that it is further away from the See details

What other noises are associated with large wind projects? Wind turbines are large pieces of industrial equipment, and installing them is, in essence, a major construction project. The construction phase of a project lasts only a few months, but during that period, noises will be produced that are typical of heavy construction, including: Truck traffic: A modern wind turbine is larger than a Boeing 747, with rotor blades that weigh thousands of pounds each and must be trucked to the site along with tower sections and other large components. The sound level is that caused by a highway truck moving at slow speed. Heavy equipment: A large construction crane is usually needed to install the See details

What can be done to reduce the likelihood of a noise problem from a wind project? A noise analysis can be done based on the operating characteristics of the specific wind turbine that will be used, the type of terrain in which the project will be located, and the distance to nearby residences. Particular attention will need to be paid if residences are sheltered from the wind.
Also, pre-construction noise surveys can be conducted to find out what the normally-occurring background noise levels are at the site, and to determine later on what, if anything, the wind project has added to those levels. See details

Saturday, May 19, 2012

What other noises are associated with large wind projects?

Wind turbines are large pieces of industrial equipment, and installing them is, in essence, a major construction project. The construction phase of a project lasts only a few months, but during that period, noises will be produced that are typical of heavy construction, including:

Truck traffic: A modern wind turbine is larger than a Boeing 747, with rotor blades that weigh thousands of pounds each and must be trucked to the site along with tower sections and other large components. The sound level is that caused by a highway truck moving at slow speed.

Heavy equipment: A large construction crane is usually needed to install the nacelle and rotor atop the turbine tower. Cement mixing is necessary for turbine foundations. The sound levels of this

equipment is comparable to a highway truck moving at slow speed.

Foundation blasting: May occasionally be required if the wind plant is being installed in hilly or mountainous terrain where bedrock is close to the surface and cannot be broken up by other means. More frequently, foundation holes are excavated using backhoes, sometimes with a pneumatic hammer to break up subsoil rock.

Obviously, it is desirable for construction activities that are likely to produce noise to be scheduled during normal working hours.

What other noises are associated with large wind projects?

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