Technology

Wind energy has become the least expensive renewable energy technology in the world due to the soundness of its energy source. Economies of scale can also be achieved when building larger wind farms. Even though the development of wind farms is a capital intensive industry, no fuel costs are involved. Increases in the price of fossil fuels do not have an impact on the wind energy industry.

The energy produced by a wind turbine throughout its 20-year lifetime (in an average location) is eight times larger than the amount of energy used to build, maintain, operate, dismantle, and scrap it. In other words, on average it takes only about 6 months for a wind turbine to recuperate all the energy required to build and operate it.

Yes. High-quality modern wind turbines frequently have an availability factor above 98% (i.e., the turbines are designed to operate, on average, during more than 98% of the hours in a year).

This availability factor is similar to or even exceeds other electricity generating technology. Modern wind turbines require maintenance checks only every six months and are built to very exacting industrial standards.

Manufacturers of large, modern wind turbines expend considerable effort to ensure their machines are as quiet as possible. With years of experience installing machines in areas of high population concentration, especially in Europe, turbine manufacturers and engineers have developed quieter machine technologies.

One source of noise from a turbine is aerodynamic noise—i.e., the “swish” sound that the rotor blades make as they pass the tower of a wind turbine.Aerodynamic noise primarily occurs at the tip and the back edge of the rotor blade.The higher the rotational speed, themore noticeablethe sound.Aerodynamic noise has been cut dramatically over theyears due to better rotor blade design, particularly in the blade tips and back edges,and lower RPM machines.Rotor blade manufacturers take extreme care to ensure a smooth surface, which is important to reduce noise.

It is important that developers perform careful turbine siting, which in turn regulates the amount of noise produced. There are many techniques used to develop low-impact turbine locations: developers place turbines at a sufficient distance from homes, factor in the prevailing wind direction and the attenuation characteristics of the surrounding terrain, and understand the effects of other noise contributors such as yard noise and traffic sounds. As an effect of this turbine siting, an average residence in a well-designed project area should have turbines that produce sound levels similar to that ofa kitchen refrigerator. You are more likely to hear the wind over the sound made by the turbine.

Wind resources are plentiful, and North America has some of the windiest sites in the world. Plus, the wind will not run out.However, not all land is windy enough to support a large scale wind farm. EDP Renewables North America seeks the windiest areas that have both access to transmission and electricity demand.

A far greater capacity of wind energy is produced each year compared to nuclear energy. Over 16,800 MW of wind power capacity was installed in the United States as of January 2008, which has generated over 51 billion kilowatt-hours of electricity annually. That is enough energy to power over five million average American households. Third-party experts are anticipating that the American market will continue its growth—increasing over threefold by 2015.

Wind energy leaves no harmful emissions or residues in the environment. Wind energy has a proven safety record.

On open, flat terrain, a utility-scale wind farm will require about 100 acres per MW of installed capacity. However, less than 5 percent, or 3 acres, of this area is actually occupied by turbines, access roads, and other equipment; 95 percent remains free for other compatible uses like farming and ranching. A wind farm located on a ridgeline in hilly terrain will require much less space, as little as two acres per MW.

Since wind turbines extract energy from the wind, there is less energy and more turbulance in the wind shade of a turbine than in front of it. On a wind farm, turbines are generally spaced between three and nine rotor diameters apart in order not to shade one another. If there is one particular prevailing wind direction, turbines may be spaced very closely in an orientation that is at a right angle to the wind direction to avoid shading. For instance, if the prevailing wind blows from the west, turbines may be placed north-south.

Wind turbines are obviously very visible, since they must be located in the windy, open terrain to be economical. Many factors can improve the visual impact of wind farms including a good design, the careful choice of paint color, and precise visualization studies before siting. As other well-designed structures, wind turbines can furnish a landscape with new architectural values.

After the useful life of a wind farm has elapsed, foundations can be reused or removed completely. Because there is so much steel in a wind turbine tower, the scrap value of a turbine more than covers the costs of restoring a site to its initial state.

Deer and cattle habitually graze under wind turbines and sheep seek shelter around them. While birds tend to collide withstructures such as electrical power lines, guy wires, masts, and buildings, they are very rarely affected directly by wind turbines. Wind's overall impact on birds is low compared with other human-related sources of avian mortality, such as hunting, house cats, buildings, and automobiles. Horizon Wind Energy conducts extensive wildlife studies before, during, and after projects are built. We work with environmental groups, federal and state regulators, and other interested parties to ensure we are responsible environmental stewards.

Landowner safety is our primary concern. Typically, wind turbines are placed a minimum of 1,000 feet away from houses,300 feet from non-participating landowner property lines, and 1,250 feet from non-participating landowner houses.

Terrain is also important. The energy content of the wind varies with the cube (i.e., the third power) of the wind speed. Twice as much wind yields eight times as much energy. Therefore, manufacturers and wind farm developers seek to site wind turbines in the windiest areas possible. The roughness of the terrain, its contours, and even the presence of buildings, trees, plants, and bushes affect the local wind speed and may create turbulence, which may decrease energy production and increase the wear and tear of the turbines.

Wind farms are typically multi-million dollar projects that provide significant tax revenues for rural communities. These revenues often serve to lower tax rates for other residences and businesses.

Local wildlife studies are conducted prior to constructing a wind farm to ensure the project is developed in the most environmentally friendly way possible. Most wildlife is not negatively impacted by wind farms. Birds and bats occassionally collide with wind turbines, as they do with other tall structures. Except for a few areas of the country (the Altamont Pass in California), these impacts are generally considered to be low and are not a major concern. Wind's overall impact on birds is lower than other sources of avian mortality such as vehicles, buildings and house cats.

Wind energy is one of the safest generating technologies in the world. Some of the many safety features include shutdown at high wind speeds and lightning protection.

If a power system were relying on wind energy to meet 100% of its needs, the intermittent nature of the wind would be a problem. But wind energy today is used on a much smaller scale - less than 1% of the nations electricity supply currently comes from wind energ. And there is enough flexibility built into the system to accommodate the fluctuations in the power produced at a wind farm.