Wind Energy

• started with simple, light devices by aerodynamic drag forces, then to heavy, material-intensive drag devices

• earliest known use of wind power is sail boat, then windmills • earliest known design of the windmill is vertical-axis developed in Persia about

500-900 A.D. • most scienic and successful applicants of windpower is the use of water

pumping machines on island of Crete • original heyday of wind in United States was between 1870 and 1930 • thousands of farmers all around the country used wind to pump water • started off as small electric wind turbines in rural areas around the 1920's

larger machines were built around the 1940's • interest in wind power decreased when effiecent methods were made, but then

came back during energy crisis in the 1970's • boost for wind developement was provided in early 1990's due to

improvements in technology which led to an increase in turbine reliability and lower costs of production

History of Wind Power

How Wind Power Works• when sun heats up an area of land, the air around that land mass absorbs the heat • once at a certain temperature, the hotter air begins to rise very quickly because a

given volume of hot air is lighter than an equal volume of cooler air • particles moving faster exert more pressure than slow-moving particles • rotor blades- blades that are the sails of the system; act as barriers to the wind • shaft- connected to the center of the rotor; when rotor spins, shaft also spins so

the rotor transfers its mechanical rotational energy to the shaft which then enters electrical generator at the other end

• generator- uses properties of electromagnetic induction to produce electrical voltage

• if wind speed doubles, then the power output increases eight times • wind speeds are divided into seven classes (class 1 is the lowest, class 7 is the

highest) • wind turbines operate over a limited range of wind speeds • if the wind is too slow, then there won't be enough power for it to run but if there is

too much wind, then it will shut off to avoid being damaged

• modern turbines use aerodynamic principles to capture wind's energy more efficiently

• two primary forces in wind-turbine rotors are lifts and drags

• turbine blades shaped like air plane wings • comes in many different designs; big or small • most common style is the "horizontal axis design" • this turbine has 2 or 3 blades that spin upwind of the

tower that it sits on • small wind turbines are used for providing power off

the grid

Turbine Aerodynamics

• one of cleanest, most sustanable ways to generate electricity

• doesn't produce toxic emissions and no heat trapping emissions that contribute to global warming

• fastest growing source of electricity in the world • 2008-more than 27,000 megawatts new were installed

worldwide • form of solar energy• caused by uneven heating of atmosphere by the sun,

irregularities of earth's surface, and rotation of the earth• wind flow/motion energy can be used to generate electricity

Information About Wind Energy