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Wind

“Wind power” and “wind energy” are phrases used to describe the process by which wind is used to generate mechanical power or electricity [1]. Wind is a form of solar energy created from the heating and rotation of the Earth’s surface and is largely determined by weather patterns, the surface of the Earth, and bodies of water [1, 2]. Since wind is technically solar energy, many advocates of solar energy development classify wind power as solar power [3].

Humanity has used the power of wind to do work for thousands of years. The first use of a large windmill to generate electricity was a system built in Cleveland, Ohio, in 1888 by Charles F. Brush [4, 5]. Similar to this original design, today’s massive wind turbines harvest air masses by capturing kinetic energy and directly transforming it into mechanical or electrical energy [1, 2]. Because this transformation takes place directly in the wind turbine, wind energy is an ideal source for remote or decentralized applications, or those places where wind conditions are the most ideal. Wind turbines come in a variety of sizes and power ratings for a vast array of applications.

The advantages of wind power are plentiful, including the fact that wind generation produces no air emissions, wind power is received well by the public, wind turbines have a small footprint and can be located on farming or grazing land, turbines can be constructed quickly, there are no fuel costs, wind is the lowest-cost non-hydro renewable energy source, and of course, wind is renewable [1].

Partly due to these benefits of wind power, the American wind power industry has shown remarkable progress, increasing by an average 34% each year between 1981 and 2002. By end-2002 capacity stood at approximately 4,700 MW (27 states) and by end-2003 (by which time it had overtaken Spain to be second in the world), approximately 6,400 MW (30 states) [6]. In 2004, wind power grew 26%, contributing a record of about 18 TWh to total electric generation [7]. Worldwide, there is more than 25,000 MW of installed wind generation [1].

The Energy Information Administration (EIA) estimates that the raw wind resource potential of the US is in excess of 3,000 GW [6]. This estimate excludes offshore areas, areas with poor wind potential (average annual wind speeds less than 7 m/s), areas with specific legal or technical restrictions on development for wind use (such as areas with high slope, environmentally restricted areas and urban areas), and areas greater than 20 miles from existing transmission lines [6]. Indeed, estimates indicate that only 0.6% of US land mass would be required to generate 20% of US electricity needs. North Dakota alone has enough areas with high wind to potentially supply 36% of the total electricity consumption of the lower 48 states [1].

Although most wind turbines produce under 1 MW of electricity each, the largest turbines, such as those developed by Germany’s Enercon, deliver up to 6 MW with an overall height of 610 feet.

Despite wind power’s potentials, a vast majority of the resource has not been utilized due to lack of effective state and federal policies as well as other barriers. Although the future of wind power is very promising, further efforts need to be made to develop technologies that utilize low wind-speeds and thus can be applied more universally [2]. Furthermore, there exist challenges in the fact that most good wind sites are in remote locations, interconnection with the grid is a continually challenging endeavor, aesthetic issues play concerning roles, wind is an intermittent source and does not always blow when electricity is needed, and although price has been reduced dramatically, wind energy in general has not yet demonstrated its ability to compete in cost-effectiveness with fossil fuels [1].