An Overview On The Environmental Issues Related To Wind Energy
Wind energy is renewable and can undoubtedly be an efficient alternative to fossil fuels, but there are few negative impacts that wind energy has on the environment, which can be understood when a detailed Environmental Impact Analysis (EIA) is done. These factors have to be considered whenever a major wind project is being undertaken at a particular site.
Firstly one of the major issues with wind turbines is that, with the high speed rotation of the turbine blades, undesirable aerodynamic noise is created. There are also high decibels of mechanical noise generated from the moving shaft and the gearbox. Many wind turbines have Spur gears that are most economical, but generates more noise. Some of the newest types of gears include the helical gears and herring bone gears, which generate extremely low noise, but they are not very cost effective. There are certain allowable limits set for the noise levels generated by the turbines, which are 35 decibels at night and 45 decibels in the daytime, but wind turbine operations are dynamic depending on the wind speed, and these acceptable limits might get exceeded causing inconvenience to the inhabitants in the surrounding regions.
The second major issue with wind energy is the fact that wind turbines are huge and they cast a shadow in the direction of the sunlight. When the blades of the turbine rotate with high kinetic energy, they pierce through the sun rays, which cause flickering. In countries like Germany, there are regulations that are set to control the level of flickering, according to which, only 30 hours of flickering per year is allowed for every wind farm that is set up, such methods actually help in planning the wind turbine set up in such a way that the flickering is kept as minimal as possible.
Thirdly the visual impact of the wind turbine is another issue, for which certain sets of limits cannot be measured or determined. In order to obtain large amount of power, many wind turbines will be present on a landscape, creating a large wind farm. With this residents dwelling near the wind farms, might find wind turbines to be too destructive too to the landscape. There are some companies like Enercon that are coming up with wind mills that are painted with certain colors like green or grey so that they are in harmony with their surroundings.
Another disturbing issue with the wind turbine is that they affect bird movement causing their death by collision. Although steps have been taken to set up wind farms at certain considerable distance from sites where birds breed, it has been estimated that in Germany every year there is 8000 bird deaths. This could be avoided by designing the rotor blades in such a way that they are more visible to the birds and keeping the migration paths of birds free of any turbine movement.
The wind turbines require a large amount of energy, while they are getting built. Offshore wind turbines need a larger amount of energy, than the onshore ones. The energy payback time of off shore wind turbine is about 7-8 months. In addition to this some of the other negative consequences of wind energy include, the fact that wind turbine components like the blades and the nacelle are made of fiber particles that have to be recycled carefully, otherwise they might cause harm to the environment. Hence required modifications have to be made in the current existing wind turbines so that they prove to be an efficient source of renewable energy.
