What is the impact of wind energy on the environment?
18.03.2016

The period of studying the environmental aspects of wind energy is not long enough to have an accurate assessment. This is especially true for the regions where the use of wind generators is relatively recent. In addition to the underexplored mainland wind energy, the study of the effect of offshore wind energy on the marine and coastal biocenosis is considered an even more challenging task.


NOISE

Studies conducted with the support of the international wind energy organizations have identified the existence of two types of noise from wind generators:

Noise having mechanical origin (caused by the operation of the mechanical elements of the device). These types of noise are only related to the earliest models of wind turbines, and in the modern models, they are largely insulated by the efficient use of sound-absorbing elements.

Noise having aerodynamic origin (caused by the wind flowing on the blade).

The noise level can be determined by various factors: the particular working conditions, a type of construction, operational characteristics, location, and others.

Currently, there are many methods of determining the permissible values of noise characteristics of wind power turbines, as they are normalized to the values of national safety regulations.

Wind turbine manufacturers themselves consider the presence of the noise a sign of the ineffectiveness, so they place greater focus on this aspect. In the wind power industry, the ultimate noise level is considered to be 40 decibels at a distance of 300 meters from the wind turbine. The distance of 300 meters is the minimum legal distance (in most countries) from the residential area, and the noise figure of 40 dB analysts compare to the natural background noise at night in rural areas (on average it is 20-40 dB).

Therefore, with proper respect for the process of designing and placement, modern wind turbines produce very little noise, fixed only at the level of background values.

Studies of low-frequency sound produced by wind generators have not revealed the values that cause a significant risk to human health.


IMPACT ON FAUNA

The main negative impact of wind energy on the nature is considered to be the death of birds. This is due to the presence of extensive research in the countries with developed wind energy, where the wind turbines are located mainly in the coastal areas (seas, rivers and lakes), which are the natural habitats of birds.

The study of the interaction of wind turbines and avifauna found the following instances of negative effects:

- wind turbines scare away birds, disturbing their nesting and feeding;

- blades cause injury, leading to the death of birds.

However, most of the obtained data show a negligibly small number of deaths of birds in comparison with the other elements of anthropogenic influence.

The American Wind Energy Association (AWEA), for example, gives the following information:

 

Causes of death of birds (per 10000)

number

 

Houses/windows

5500

 

Cats

1000

 

Other causes

1000

 

Pesticides

700

 

TV towers

250

 

Wind turbines

1

 

At the same time, in order to prevent the increase in the negative impact on nature, ethologists recommend to carefully choose the location of wind turbines (to avoid the migration routes of birds, the most common places of feeding and breeding); to use modern wind power turbines with blades that rotate more slowly, which reduces the probability of collision with birds.


IMPACT ON THE CLIMATE

The impact on the local climate conditions can be caused both by a change in the strength or direction of air flows and their mixing.

It is believed that at places of large accumulation of wind generators, there may be some impact on climate change. The blades of wind turbines quench a part of the kinetic energy of the wind flow passing through them, which reduces the air velocity. As a result of slowing down, the air masses can become very hot during the hot period and cool down in the cold. It is assumed that these effects can have both a negative impact (e.g., undesired change in temperature) and positive (e.g., reduction in power of hurricanes or night warming-up of agricultural land). Scientists are searching for evidence to confirm the put forward theories, but accurate scientific data have not been received yet.

Nevertheless, most experts are convinced that the kinetic impact of wind energy has negligibly small effect on the global climate change. Not to mention the huge proven benefits of reducing CO2 emissions by substitution of fossil energy sources.


Thus, having analyzed the available materials, it is possible to form a clear conclusion that wind energy does no tangible harm to the environment (or the harm that could be weighed against the benefits obtained).

 


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