• Wind is a form of solar energy that occurs when the sun heats the air, which causes the air to rise, creating a vacuum. That vacuum pulls in cooler air creating wind. Scientists estimate that some 2 percent of sunlight energy received by the earth is converted to kinetic energy of the winds. (Righter 3)
• Tenth century, vertical carousel-type mills were used in Persia to grind corn and raise water from streams for irrigation.
• European post-mill (whole tower and mechanism turned to face the wind) profoundly affected European development from the twelfth to nineteen centuries. The first English post-windmill was erected in 1137 A.D. by William of Almoner of Leicester. (Righter 10)
• The Dutch adopted tower-mill windmills where only the tower and sails changed direction with the wind.
• Uses include grinding pepper and other spices, cocoa dyes, chalk, and paint pigments. Lumber companies employed them as primary power for saw mills. Paper companies used windmills to reduce wood to pulp for paper.

• The first windmill was unsuccessful in early America do to its high maintenance but after some refinement and experience with them it became useful.
• American Windmill success increased as people moved west. Approximately six million American windmills were operating in the Great Plains and the West between 1880 and 1930. (Righter 28)
• Modern windmills use the power of the wind to produce electrical energy through the use of turbines

• Turbines operate through the principles of lift and drag to drive their blades through the air. (Office of Utility Technologies 2)
• Drag devices, such as the cup anemometer or the Persian panemone use the force of the wind striking the blade to push rotor about its axis.
• Lift devices use the difference in pressure created by the flow of air over the wing. All modern wind turbines use aerodynamic lift to drive their blades through the air. (Gipe 17)
• There are two main types of wind turbines, Horizontal Axis Wind Turbines (HAWT’s) and Vertical Axis Wind Turbines (VAWT’s).

• By far the most commercially used and efficient style of turbine is the Horizontal Axis Wind Turbine. (Wind Energy Program 3)

• VAWT’s have two basic types: lift and drag. Drag-based designs work like a paddle used to propel a canoe through the water. If you assume that the paddle used to propel a canoe didn’t slip then the maximum speed of the canoe would equal the speed of drag. This same principle holds true for wind. (Eggleston 1)
• A Savonius rotor is a drag type VAWT that has a S-shaped rotor. It turns slow (below 100 RPMs), but yields high torque. These types are generally not good for generating electricity.

• A Darrieus machine (as shown above) is named after the French engineer Georges Darrieus who patented the design in 1931. The Darrieus is a lift type VAWT sometimes called an "eggbeater". It usually has 2-3 blades that see maximum lift (torque) only twice per revolution. This makes for huge torque (and power) not present in HAWT’s. The largest Darrieus prototype was located in Quebec, Canada. It has a 100M rotor diameter and produces 4200 KW. This particular turbine is no longer in service.
• A variation on the Darrieus is the Giromill: a VAWT with straight vertical blades.
• One advantage of VAWT is that the generator, power train, etc. can be placed on the ground for easy access. Also you do not need a "yaw" mechanism to turn the rotor into the wind.
• VAWT’s have not become popular because of poor performance and reliability.
• Disadvantages of the VAWT:
• The VAWT is mounted close to the ground where wind speed is low.
• They are inefficient
• Turbine needs a motor to start it moving
• Needs guy wires that are impractical in heavily farmed areas
• Replacing the main bearing requires taking the whole machine down. (Krohn 2)

• Almost all conventional wind turbine rotors spin about a horizontal axis. HAWT’s account for 94 percent of California’s generating capacity. (Gipe 170)
• Modern HAWTS typically use 2-3 blades although 1 blade is possible.
• HAWT’s are made up of a tower and a rotor. The main components of the rotor are blades fastened to a central hub. The blades of a HAWT work almost like an airplane propeller except airplane propellers are wind accelerators and wind turbine blades are wind decelerators.
• Early American HAWT designs oriented their rotor down wind of the tower. By sweeping the blades downwind the spinning blades take the shape of a shallow cone. This shape causes the rotor to automatically orient itself down wind regardless of wind direction. Some designs, however, tended to "walk" around the tower during heavy turbulence. Coning also reduces bending forces on the blade root. Coning angles vary from 1 to 2 degrees for heavy blades to 6 to 8 degrees for light blades.
• By the late 1980’s turbine design had largely gone to upwind rotors and by the mid 1990’s no major manufacturer was building downwind models. (Gipe 175)
• Upwind HAWT’s must orient themselves into the wind with an electrical "yah" that points the nacelle into the wind.
• One problem with the HAWT system is that the power train equipment is located at the top of the tower. The power train consists of a series of mechanical and electrical components required to convert the mechanical power from the rotor hub into electrical power. It is important that the power train equipment is low maintenance so it is not necessary to go to the top of the tower or disassemble the turbine to fix the train. (Spera 50)
• One large-scale prototype that can be used to illustrate a modern HAWT is the DOE/NASA Mod-5B located on the Hawaiian Island of Oahu. The Mod-5B with its 97.5m rotor, swept area of 7,470 m2 and has a 3.2MW rating, is the largest wind turbine in the world. It is owned by the Makani Uwila Power Corporation and is operated as a commercial power plant. (Spera 48)

• The biggest environmental impact of wind power is its visibility, but this can be overcome. The Danes have proven it can be done at Taendpibe-Velling Maersk, Noerraker Enge, and other sites, the British in hilly Cornwall as well as in mountainous Wales, the Germans on the polder at Frederick Wilhelm Lubke Koog, and the Dutch on the dikes at Urk and Leystad. (Gipe 291)
• More people accept wind power as part of the landscape than may other type of power generator. 25% accept Nuclear, 30% Fossil, 45% Biomass, and 60% acceptance rate for wind (Gipe 286).
• People will live closer to wind power plants followed by biomass, fossil, and nuclear respectively (Gipe 286).
• Wind was also considered to have the best visual quality, health and safety, environmental, and overall acceptance when a survey was done in Solano County in California (Gipe 287).
• Most wind generator farms in California boarder major highways so most people see them as part of the landscape. The view when first entering one of these mountain passes has variously been described as riveting, other worldly, or shocking (Gipe 289)
• People living near wind generators want the machines a dull color or white so they don’t "sparkle" in the sun and draw attention.
• From his surveys in California, Robert Thayer recommends that developers bury all power lines and integrate extraneous equipment, such as transformers, into the turbines themselves (Gipe 315).
• Minimizing fencing, lighting, and roads will help to minimize visual impact.

• Wind power is an alternative to polluting Fossil fuels and other depleatable resources.

• Wind power is a clean and never ending resource

• Community opposition to something new is, and always should be, expected.
• Society as a whole shares the benefits accruing from power plants: the electricity (Gipe 324).
• Ownership by the community can help to spur acceptance by the people.

• Wind power is categorized from classes 1 through 7. One being the lowest amount of wind, seven being the highest.
• Areas designated as class 3 or higher are suitable for most turbine applications (Spera 373).
• The North West Region consists of Idaho, Montana, Oregon, Washington and Wyoming. The Oregon and Washington coast has class 4 winds at 50M (164 ft). The Columbia River Corridor on the Oregon/Washington border has an average annual average wind resource at class 3 to 6 during the spring and summer seasons. This area is the site of three MOD-2 wind turbines. The Central Washington corridor, Northwestern Montana Plains, Southwestern Montana, Southern Wyoming and the Western Wyoming Corridors all have many possible turbine sites with winds from class 3 up to class 6 annual average wind resource (Wind Energy Resource Atlas of the United States 3-5).
• The North Central Region consists of Iowa, Minnesota, Nebraska, North and South Dakota. Class three and higher wind energy potential exists at exposed areas throughout this region. New measurements indicate that the annual average wind resource may even be class five to six in certain areas (Wind Energy Resource Atlas of the United States 5).
• The Great Lakes Region Consists of Illinois, Indiana, Michigan, Ohio and Wisconsin. Class 3 and higher wind potential is estimated for exposed coastal and shore areas of Lakes Erie, Huron, Michigan and Superior (Wind Energy Resource Atlas of the United States 8).
• The Northeast Region consists of Connecticut, Massachusetts, Rhode Island, Maine, New Hampshire, Vermont, New Jersey, New York and Pennsylvania. The winter season has the highest annual wind resource reaching class 3 in all but the most sheltered areas of the region, and coastal and mountain summits reaching classes of 6 to 7 (Wind Energy Resource Atlas of the United States 10).
• The East Central Region consists of Delaware, Kentucky, Maryland, North Carolina, Tennessee, Virginia and West Virginia. Aside from coastal areas and exposed mountains and ridges of the Appalachians there is little wind energy potential in this region (Wind Energy Resource Atlas of the United States 12).
• The Southeast Region consists of Alabama, Florida, Georgia, Mississippi and South Carolina. There is little Wind energy potential in the southeast region for existing wind turbine applications (Wind Energy Resource Atlas of the United States 14).
• The South Central region consists of Arkansas, Kansas, Louisiana, Missouri, Oklahoma and Texas. Since the completion of the Regional Wind Energy Atlas, four sites were instrumented for the DOE candidate site program. These were located near Amarillo, Texas; Mead and Russell, Kansas; and Fort Sill, Oklahoma (Wind Energy Resource Atlas of the United States 14-15).
• The Southern Rocky Mountain Region includes Arizona, Colorado, New Mexico and Utah. This region has many potential turbine sites with wind classes ranging from 3 all the way to 7 in the San Andres Mt. of southern New Mexico (Wind Energy Resource Atlas of the United States 19).
• The Southwest Region includes California and Nevada. Extensive land resource assessments have been conducted throughout California by the CEC. More wind turbines have been sited in California then in any other region in the United States. In addition the DOE has sponsored wind measurement programs on 3 sites in California.

• The future of wind power is promising because of the growing need for alternative power sources. The depletion of fossil fuels in the not so distant future makes wind power a promising way to produce electricity that we have come so dependent on.
• The need to be environmentally friendly has grown steadily in the last decade and wind power is as clean as it gets.
• With increased interest and funding the research and development of new and more efficient wind turbines will help to make this industry a larger segment of the electric power industry.

Eggleston, Eric. What are Vertical-Axis Wind Turbines? [Online]. Available:

http://www.igc.org/awea/faq/vawt.html (10-10-99).

Gipe, Paul. Wind Energy Comes of Age. John Wiley and Sons Inc. : New York, 1995.

Righter, Robert W. Wind Energy in America. University of Oklahoma Press: Norman,

1995.

Select Wind Facts [Online]. Available: http://www.eren.doe.gov/wind/windfact.html (10-10-99).

Spera, David A. Wind Turbine Technology. Asme Press: New York, 1994.

Wind Energy Resource Atlas of the United States [Online]. Available:

http://rredc.nrel.gov/wind/pubs/atlas/chp3.html (11-2-99).

Wind Turbines: Horizontal or Vertical Axis Machines? [online]. Available:

http://www.windpower.dk/tour/design/horver.htm (11-2-99).