Alternative Energy, Wind (Global Warming)

Wind is a source of solar energy that does not rely on the condition of the sky. Unlike fossil fuels, wind energy can be collected during storms, snow, or the night. Wind power is the alteration of wind energy into more purposeful forms, usually electricity using wind turbines, and is a form of renewable energy. Wind power is greenhouse gas extenuating, clean, abundant, infinitely renewable, domestically produced, widely distributed, and supportive of rural economies.

The International Energy Agency (IEA) projects that, 2000-30, global energy consumption will increase and electricity use could double, placing pressure on nonrenewable resources, public health, international stability, and the natural environment. One solution lies in finding and utilizing alternative energy sources. Renewable energy sources pose lower costs, whether environmental or health-related. The use of alternative energies to generate electricity is especially advantageous to developing countries, because of the new employment opportunities it will create, as well as the stimulation of local economies by attracting investment. One of the resources leading the way to a more sustainable future through the use of alternative energy is wind power.

People have been harvesting the wind for hundreds to thousands of years, with functions varying from sailing, to grinding grain, to pumping water. Windmills have been found dating back to 10th century Persia, while their appearance in Europe is believed to have begun around the Middle Ages. It was not until the 20th century that people became interested in using the wind to generate electricity. In 1941, the 1,250 kilowatt (kW) Smith-Putnam wind turbine was constructed in the United States. There are records of 100 kW turbines in the former Soviet Union in 1931, and other innovative designs originating in Germany during the 1950s to the 1960s. However, after the 1950s, lower-cost fossil fuels made wind energy technology economically unprofitable, and only in the 1970s did rising fuel prices bring it back into popularity.

Projects like this wind farm in California may help the U.S. Department of Energy's Wind Powering America Initiative reach its goal of generating 5 percent of the nation's electricity through wind power by the year 2020.

Projects like this wind farm in California may help the U.S. Department of Energy’s Wind Powering America Initiative reach its goal of generating 5 percent of the nation’s electricity through wind power by the year 2020.


Wind energy moves over the Earth’s surface as kinetic energy. This energy is received by the blades of a turbine, which is attached to an electrical generator that sits atop a collection tower. Collection sites consist of a single turbine, or many, constituting a wind farm.

Each turbine consists of a tower structure, rotor with blades attached to the hub, shaft with mechanical gear, electrical generator, yaw mechanism, and sensors and control. Modern structures must come equipped with a control system for operational and safety functions.

Certain terms are necessary to understanding of the wind industry. The gearbox increases the turbine speed from around 45 rotations per min. (rpm) to about 14,500 rpm. The rotor connects to the nacelle, which sits atop the tower and contains the gearbox. Upwind refers to a turbine operating facing the wind in front of the tower. Downwind turbines run facing away from the wind behind the tower. Finally, the yaw drive maintains the direction of the upwind turbine facing the wind.

The tower is the support structure. It can be steel or concrete, and tubular or lattice. They must be at least 82 ft. (25 m.) tall to capture adequate energy. The turbines range in size from a few kW to a few megawatts (MW), used for utility-scale power generation. Turbines usually consist of two or three aerodynamic blades constructed to capture the most energy possible. The blades operate using the Bernoulli principle. A lift is created by the difference in pressure on the sides of the blades when the wind flows over it. The lift rotates the blades around the hub. A drag force is created that acts perpendicular to the blades and slows down the rotor. The purpose of this design is to achieve the highest drag to lift ratio, optimizing the turbine’s power.


When assessing the introduction of wind energy conversion to a new area, it is important to consider the environmental, economic, and social impacts. Birds feel the environmental consequences of collecting wind energy, and humans experience noise emissions and the visual impact of the turbines. The presence of turbines may alter the breeding and feeding patterns of some avian species. Some birds have been killed or injured from collisions with blades. Some may be sucked into the draft created by the rotating blades, but some may just be attracted to the hum of the machine. However, the 300 birds killed in Altamont Pass, California, in the 1980s do not seem as significant when compared with the millions of birds killed by U.S. hunters and the one billion birds killed annually by flying into glass windows. To combat these occurrences, certain measures have been put in place, such as avoiding migration routes and using fewer, larger turbines.

The visual aspect may not be considered an important environmental impact, but it has generated public concern. The elements that must be considered are the number and design of turbines, the turbine arrangement, their color, and the number of blades. The wind turbines may not be aesthetically pleasing, but it is hoped that with the knowledge of the technology and services they deliver, they will become more acceptable.

Noise emission due to wind energy is another consequence that is relative to the public’s perception. Its impacts can range from annoyance, to sleep interruption, to effects on hearing. A 600 kW wind turbine will produce around 55 decibels (dB) of noise when a receptor is 164 ft. (50 m.) away. This amount will decrease as the distance increases. This level falls in between that of the noise produced in the average office (50 dB) and that of an average factory (60 dB). While this may seem a tolerable amount, it is dependent on individuals’ personal discretion and tolerance. Because an individual’s level of tolerance of noise is subjective, there is no way to please everyone; hopefully public education about the technology will increase acceptance.

The economic impact of employing wind technologies is beneficial. This would be especially helpful in developing countries where billions of people still lack access to electricity and other modern forms of energy. Limited access to fossil fuels and the abundance of renewable, sustainable sources has led to the creation of 100,000 jobs in the wind industry worldwide. In 2003, $9 billion was invested in the wind industry globally.

This influx could greatly assist weaker, developing economies. The decreasing costs of the operation and services provided by wind energy are also appealing to poorer countries. By 2020, the cost may even be reduced to 2.6C/kW hour.

One of the factors determining the economic worth of wind energy production is siting. The strength of wind spectra is one of the critical factors in deciding the cost of wind-generated electricity. Therefore, as the velocity of the wind increases, the cost is reduced. Also included in site-specific factors are the cost of land, installation, and environmental factors such as climate and harmful substances in the atmosphere.

Machine parameters include the cost of the turbines themselves. The cost of wind-generated electricity can be reduced with an increase in turbine size. When the size is scaled up from 20 kW to 50 kW, the cost/kW is reduced by 18 percent. Other factors that influence the cost are the existing energy market and policy issues, including incentives and exemptions. With the goal of promoting clean and easily accessible energy sources, several governments are giving financial support to the development of renewable energies.


Despite the limitations and boundaries that wind energy may extend, Germany has proven to be a success story and has become the world leader in wind power. In the early 1990s, Germany started out with almost no renewable resource industry, and it seemed unlikely that it would ever be considered a leader in these technologies. The decision of the German government, in 1990, to pass a law that required utilities to purchase the electricity generated from all renewable technologies, and to pay a minimum price, was governed by the public’s increased concern about the security of energy supplies and its environmental impact.

The results that Germany has experienced are staggering. The average cost of manufacturing wind turbines fell 43 percent 1990-2000. In 1997, Germany surpassed the United States to become the world leader in wind energy production. The percent of total electricity accounted for by wind power has increased from 3-6 percent 2001-07. In 2002 the renewable resource industries totaled $11 billion in sales. Nearly 45,000 Germans were employed in the wind industry alone in 2003. The country is taking further steps by pledging to reduce its CO2 emissions by increasing its use of renewable energy. The government aims to meet 25 percent of national electricity needs by 2025 and at least half of its total energy needs with renewable resources by 2050.

The world can learn a lesson from Germany’s innovative renewable energy technologies, especially wind power, and many nations are taking the initiative. Countries such as Spain and Denmark have established similar laws as Germany. Spain is a leading turbine producer, generated 5 percent of its electricity from wind in 2003, and has some of the world’s largest turbine manufacturers. In Denmark, 20 percent of its electricity has been generated by wind. In the United States, at least 38 states have enacted similar laws.

These numbers are projected to increase. Major oil companies, including BP and Shell, are investing hundreds of millions in renewable energy. The U.S. Department of Energy’s (DOE) Wind Powering America Initiative intends, by the year 2020, to have 5 percent of the nation’s electricity generated through wind power. The European Wind Energy Association (EWEA) has developed a program, Wind Force 12, to produce 12 percent of the world’s electricity by wind for the year 2020. Some countries may expect wind to contribute to larger percentages of their total energy by 2010.

For years, the exploiting and burning of fossil fuels has caused emissions of harmful gases and severe degradation of the environment. People worldwide are becoming conscious of the consequences of their actions for the environment. Only with a suitable amount of time, money, and energy invested in wind power can countries reap its full benefits. It does not emit pollutants into the air or water. There is no chance of hazardous waste as a byproduct of its use. The wind is a sustainable, natural, renewable resource which can never be diminished, unlike the finite supply of natural gas, coal and oil.

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