Wind energy is a converted form of solar energy. The sun's radiation heats different parts of the earth at different rates-most notably during the day and night, but also when different surfaces (for example, water and land) absorb or reflect at different rates. This in turn causes portions of the atmosphere to warm differently. Hot air rises, reducing the atmospheric pressure at the earth's surface, and cooler air is drawn in to replace it. The result is wind.

Wind turbines use large blades to catch the wind, turning rotors that produce electricity. Just as fossil-fueled plants use steam or combustion gases to turn electricity-producing rotors, wind plants use many wind turbines, often assembled on a large single wind site called a wind farm, to generate electricity. The modern wind farm may consist of as many as 100-500 wind turbines connected to the electric transmission grid.

Wind turbines commonly begin to produce power at a wind speed of 10-12 miles per hour. Wind plants produce electricity only when the wind blows, so if the wind is not blowing, the plant is not producing electricity. For this reason, wind is called an intermittent resource.

Because wind follows patterns that can be predicted, and because particular locations have more reliable winds and will produce power more regularly, the value of wind for meeting consumer demand can be significant. Further, the intermittent nature of wind power does not produce significant problems for large electric systems as long as wind is a small proportion of the total system (less than 2-3 percent of total local system capacity).

Wind is a renewable, clean and sustainable fuel source; it does not create pollution and it will never run out. Because wind is a product of the sun shining on the earth and the earth's atmosphere, it is a resource that will not be depleted by tapping it for electricity generation.

Wind energy is available for electricity generation in locations where the average wind speeds are great enough to drive the fields of wind turbines. While the ability of wind technology to produce electricity economically at lower wind speeds is improving, areas where average wind speeds exceed 12 miles per hour are currently the most economic locations.

Wind energy technology has improved considerably since the 1970s, resulting in a dramatic decrease in the cost per kilowatt of wind capacity.   Wind energy technology is developing fast and turbines are becoming cheaper and more powerful, bringing the cost of renewably-generated electricity down.