Wind power, or wind energy, is a renewable resource; it is from the sun. The advantages of wind power are many, including practical, environmental as well as economic. There are also disadvantages to using windpower, such as the natural variability of wind, the competition for other land uses, and bird deaths.

Wind power, or wind energy, is a renewable resource; it is from the sun. The intensity of solar radiation differs across the globe. Some areas receive intense amounts of sunlight, while others receive much less. The result is a temperature gradient; a gradient which is mediated by the flow of air to and from areas of dissimilar temperatures and pressure systems in our atmosphere. Uneven heating of the earth's atmosphere,

in addition to irregularities on the earth's surface and the rotation of the earth create wind. Terrain, water bodies, and vegetation then shape flow patterns.

The recent history of wind power in the United States has a similar impetus to that of alternative fuel sources in general - it was an idea borne from the 1970's Oil Crisis. It does, however, have a more extensive history reaching back into to late 19th century in the colonization of the American West; millions of windmills were erected for irrigation and cattle purposes to facilitate the growing number of farms and ranches. Many soon feel into disrepair as inexpensive energy sources became more widespread and grid power extended its reach into rural areas used small electric wind systems.

Outside of the US, however, wind power has a broader history. In fact, there was evidence that boats were propelled along the Nile as early as 5000BC via wind energy. China used wind for pumping water several millennium ago.

Wind is harnessed to make mechanical power or electricity. The kinetic energy from the wind is converted through various different processes to create mechanical energy that can be used in lieu of fossil fuels. There are two types of modern turbines - horizontal and vertical axis, both of which work similar to one another and as decried above. Between the two types, they come in an array of sizes from small 100 watt units for single homes to much larger or ones (with a blade diameter greater than 50m). These larger turbines can generate 1 MW of electricity.

The most common used today are horizontal axis turbines with three blades (15-30m in diameter) and produce approximately 50-350 kW of electricity. Often wind turbines are grouped together; the arrangement in called a wind farm that provides energy to an electrical grid.

Vertical axis turbines are more efficient in areas with vast amount of lands and moderate wind speeds. Current technology is looking to develop different turbine types for different areas of wind speed given the amount of land available for farms.

The advantages of wind power are many, including practical, environmental as well as economic. Worldwide, the total kinetic energy contained in wind is more than 80 times that of human energy consumption. While only a fraction of this can be used for electricity purposes, the potential-given future technological developments is great.

Environmental advantages include the fact that a renewable source of clean, nonpolluting energy curbs the demand and use of fossil fuels and emit no air pollution of greenhouse gases, In the US, wind plants have offset the emission of than 2.5 billion pounds of carbon dioxide, and 15 million pounds of other pollutants. Also, wind energy is free: the cost of installation and maintenance has dramatically decreased in recent years and future technology ensures only a continual decrease in the prices. As a result, the lifetime investment is much lower than most fossil-fuel systems.

One of the primary disadvantages to wind power is the natural variability of wind in any given locale. Indeed there are certain areas with extremely high average wind speeds, but in most places, wind exposure is quite variable. Wind energy can only be stored with a battery, otherwise it is not. In the latter case, not all energy demands can be met through the natural timing of winds. For these reasons, it may not be a viable option for some. One other disadvantage is the competition for other - more highly valued and profit generating - land uses.

Economic disadvantages include the fact that the initial investment is often higher than fossil fuel systems. The higher costs is mostly due to the machinery which is involves. Other costs include site preparation and installation. The primary environmental drawbacks to wind power are as follows: Noise pollution via the rotor blades Aesthetic impacts ("visual pollution"), and bird deaths.

It is important to keep in mind that many of these problems have been resolved with increasing technology. Avian mortality, however, is still being studied.