2. For any wind turbine, the power and energy output increases dramatically as the wind speed increases (see wind power profile.wind power profile Therefore, the most cost-effective wind turbines are located in the windiest areas. Wind speed is affected by the local terrain and increases with height above the ground, so wind turbines are usually mounted on tall towers. Wind energy is the kinetic energy that is present in moving air : this kinetic energy in turn derives from the heating of the atmosphere, earth, and oceans by the sun. The amount of energy in the wind depends mainly on wind speed, but is also affected wind speed slightly by the density of the air, which is determined by the air temperature, barometric pressure, and altitude.

3. For any wind turbine, the power and energy output increases dramatically as the wind speed increases (see wind power profile.wind power profile Therefore, the most cost-effective wind turbines are located in the windiest areas. Wind speed is affected by the local terrain and increases with height above the ground, so wind turbines are usually mounted on tall towers

4. Worldwide development of wind energy expanded rapidly starting in the early 1990s. In 1999, over $3.5B was invested in farms that use wind energy. Most of the investment was spent in Europe where conventional electricity costs are higher and where political motivation to reduce greenhouse gas pollution is greater. At the end of April 1999, 10,000 megawatts of wind-generated electricity produced some 22.5 TWh of electricity. That is sufficient electricity for all the industrial, commercial and domestic electrical requirements of about two cities the size of Madrid, Spain – a total of about 8 million people.

5. Wind energy is an ideal renewable energy because: it is a pollution-free, infinitely sustainable form of energy it doesn't require fuel it doesn't create greenhouse gases it doesn't produce toxic or radioactive waste Wind energy is quiet and doesn't present any significant hazard to birds or other wildlife. When large arrays of wind turbines are installed on farmland, only about 2% of the land area is required for the wind turbines. The rest is available for farming, livestock, and other uses.

6. Landowners often receive payment for the use of their land, which enhances their income and increases the value of the land. Ownership of wind turbine generators by individuals and the community allows people to participate directly in the preservation of our environment. Each megawatt-hour of electricity that is generated by wind energy helps to reduce the 0.8 to 0.9 tonnes of greenhouse gas emissions that are produced by coal or diesel fuel generation each year.

7. We have been harnessing the wind's energy for hundreds of years. From old Holland to farms in the United States, windmills have been used for pumping water or grinding grain. Today, the windmill's modern equivalent—a wind turbine—can use the wind's energy to generate electricity.

8. Wind turbines, like windmills, are mounted on a tower to capture the most energy. At 100 feet (30 meters) or more aboveground, they can take advantage of the faster and less turbulent wind. Turbines catch the wind's energy with their propeller-like blades. Usually, two or three blades are mounted on a shaft to form a rotor.

9. A blade acts much like an airplane wing. When the wind blows, a pocket of low-pressure air forms on the downwind side of the blade. The low-pressure air pocket then pulls the blade toward it, causing the rotor to turn. This is called lift. The force of the lift is actually much stronger than the wind's force against the front side of the blade, which is called drag. The combination of lift and drag causes the rotor to spin like a propeller, and the turning shaft spins a generator to make electricity.

10. http://tonto.eia.doe.gov/kids/energy.cfm?page=wind_ home-basics-k.cfm http://tonto.eia.doe.gov/kids/energy.cfm?page=wind_ home-basics-k.cfm This is a webpage just for explaining the wind energy