1. Introduction to Alternative Energy Wind Energy Ui Luu / Engineering Special Credits: National Science Foundation APS /GE

2. What Is Wind Energy? Wind Energy is the energy contained in the force of the winds blowing across the earth’s surface. Wind Energy is the energy contained in the force of the winds blowing across the earth’s surface. Wind is created when air that has been warmed over sun- heated land rises, leaving a vacuum in the space it once occupied. Wind is created when air that has been warmed over sun- heated land rises, leaving a vacuum in the space it once occupied. Cooler surrounding air then rushes in to fill the vacuum. This movement of rushing air is what we know as wind. Cooler surrounding air then rushes in to fill the vacuum. This movement of rushing air is what we know as wind.

3. Wind In Action When wind strikes an object, it exerts a force in an attempt to move it out of the way. Some of the wind's energy is transferred to the object, in this case the windmill, causing it to move. When wind strikes an object, it exerts a force in an attempt to move it out of the way. Some of the wind's energy is transferred to the object, in this case the windmill, causing it to move. Traditional European windmills have been used for centuries on the lowlands of northern Europe. Traditional European windmills have been used for centuries on the lowlands of northern Europe. Modern wind turbines tower above one of their ancestors—an old windmill used for pumping water. (Credit: Warren Gretz)

4. History of Wind Usage   The wind is one of our earliest energy resources. Wind has been harnessed throughout recorded history, first to power boats and grind grain, later to pump water, press oil, saw lumber, and make paper.   The first windmills were mentioned at the beginning of the Islamic civilization (7th Century).   Windmills were developed in Persia about 500- 900 AD and used paddles made of bundled reeds.   Egyptians may have been the first to go up the Nile River around 4 th Century B.C., powered by wind.   Ancient Chinese used vertical axis windmills to grind grain and pump water   Windmills were introduced to Europe by the Crusaders around 1300 A.D A 19th-century American knock-off of the Persian panemone (http://telosnet.com/wind/early.html)

5. Wind Usage Today   The American farm windmill, ideally suited for pumping water from deep underground, became an integral part of agricultural communities across the American West.   The modern wind turbine is the result of design and material advances made during the 1980s and 1990s, which have enabled wind turbines to become increasingly efficient.   Today, wind turbines the same size as the traditional European windmill can generate 250 to 300 kilowatts of power— a nearly tenfold increase in efficiency.

6. Wind Power is a form of Solar Energy Wind power is a form of solar energy. About two percent of the sun's radiation that falls on the Earth is converted to wind energy through the heating and cooling of the earth's surface. Wind power is a form of solar energy. About two percent of the sun's radiation that falls on the Earth is converted to wind energy through the heating and cooling of the earth's surface. When areas of the earth heat up, the hot air rises and cooler air rushes in, creating wind. When areas of the earth heat up, the hot air rises and cooler air rushes in, creating wind.

7. Wind Turbine Generates Electricity When the wind blows, its energy can be used to turn the blades of a wind turbine. When the wind blows, its energy can be used to turn the blades of a wind turbine. The spinning of the blades sends energy to the wind turbine's generator. The spinning of the blades sends energy to the wind turbine's generator. The generator increases the voltage from 480 volts to 12,000 to 66,000 volts! The generator increases the voltage from 480 volts to 12,000 to 66,000 volts!

8. Power Transmission to Home Moving through underground cables, the electricity travels to a transformer that boosts the voltage even more, up to 400,000 volts! (They boost the voltage because it's more efficient to transport higher voltage electricity.) Moving through underground cables, the electricity travels to a transformer that boosts the voltage even more, up to 400,000 volts! (They boost the voltage because it's more efficient to transport higher voltage electricity.) Still in cables underground, the electricity is moved to substations, where it is reduced to lower voltages. Still in cables underground, the electricity is moved to substations, where it is reduced to lower voltages. Near our homes, electricity goes through a transformer to convert the power to even lower levels for use in our homes. Near our homes, electricity goes through a transformer to convert the power to even lower levels for use in our homes. The voltages in your home are 110 volts for lights, television and hair dryers and 220 volts for larger appliances such as your clothes washer and dryer. The voltages in your home are 110 volts for lights, television and hair dryers and 220 volts for larger appliances such as your clothes washer and dryer.

9. HOW DO YOU CONVERT WIND INTO ELECTRICITY? Modern wind energy systems consist of three basic components:   Tower on which the wind turbine is mounted   Rotor that is turned by the wind   Nacelle, which houses the equipment, including the generator, that converts the mechanical energy in the spinning rotor into electricity. Wind turbines are mounted on a tower to capture the most energy. www.awea.org

10. Wind Farm To create the amount of power necessary for home and business electrical use, wind farms must be built. To create the amount of power necessary for home and business electrical use, wind farms must be built. A wind farm is many turbines grouped together. A wind farm is many turbines grouped together. Wind farms are big! One turbine needs about two acres of land, but the land can still be used for farming and grazing. Wind farms are big! One turbine needs about two acres of land, but the land can still be used for farming and grazing. Wind speed increases with altitude. The taller the wind turbine, the more wind it can catch. Wind speed increases with altitude. The taller the wind turbine, the more wind it can catch.

13. Additional Sources of Information http://encarta.msn.com/encyclopedia_761559991/Atmosphere.html http://www.bergey.com/Wind_Energy_Primer/what_is_wind_energy.htm http://www.windmillworld.com/windmills/history.htm http://www.building-history.pwp.blueyonder.co.uk/Buildings/Mills.htm http://www.kidwind.org/materials/primer.html http://is2.dal.ca/~malkhali/history.htm http://telosnet.com/wind/early.html