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Wind

North Dakota State College of ScienceApplied Science and Technologies

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• Renewable energy – energy that comes from natural resources that are naturally replenished• sun• wind• rain• tides• geothermal

• The Earth receives 1.74 x 1017 watts of power per hour from the sun

• 1-2% of this energy is converted to wind• 50-100 times more than energy converted to biomass by all the plants on

the Earth

What is it?

http://www.euinfrastructure.com/news/europe-wind-energy-to-increase-by-13-percent-in-2010/

http://www.pixmac.com/picture/green+car+and+altenative+energy+icons+on+puzzle+pieces/000017090641#vlczak

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• Wind – the movement of air between pressure systems as they try to balance out.

• Air – composed of molecules of nitrogen (78%), oxygen (21%), water vapor (1-4%), and other trace elements• air molecules move quickly colliding with each other and

other objects

• Air pressure – amount of force that the air molecules impart on an area.• The more air molecules present, the more (higher) air

pressure.

• Changes in air pressure over a distance causes the wind we feel.• The air molecules from an area of high pressure will rush to

an area of low pressure (called the pressure gradient force).• The greater the pressure change in a concentrated area, the

stronger the wind or storm.

Where Does Wind Come From?

http://www.pixmac.com/picture/a+windy+day+in+the+woods/000033992343#vlczak

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Tornado

• Example – Tornado• In an F4 tornado in South

Dakota, the air pressure changed by 10% in the radius of the tornado.

• The molecules are quickly accelerated to the center of the tornado where the air pressure is low

• This phenomena causes the funnel appearance

• The magnitude of the air pressure change along with the short distance explains destructive winds.

http://www.ncwiseowl.org/kscope/techknowpark/Dream/Stress.html

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Where is it?

http://rredc.nrel.gov/wind/pubs/atlas/maps/chap2/2-01m.html

The darker the areas the windier it is

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How it Works

• A wind turbine obtains its power input by converting the force of the wind into a torque (turning force) acting on the rotor blades

• To be considered a good location for wind energy, an area needs to have average annual wind speeds of at least 12 miles per hour

• Average North Dakota wind speed is 12-15 mph

Kinetic Energy - Mechanical / Electrical Energy• Turbine•Wind turns blade - spins shaft - generator

http://tomorrowlab.cs.northwestern.edu/projects.html

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How it Works

http://greenpoweroregon.com/Images/WindDiagram_Lg.gif

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How it Works

http://www1.eere.energy.gov/windandhydro/wind_animation.htmlhttp://ocsenergy.anl.gov/

Click picture for online animation.

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Windmill Design

A Windmill captures wind energy and then uses a generator to convert it to electrical energy.

The design of a windmill is an integral part of how efficient it will be. When designing a windmill, one must decide on the size of the turbine and the size of the generator.

http://qwickstep.com/search/windmill-design.html http://qwickstep.com/search/windmill-design.html

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Creative Windmill Designs

http://www.catsailor.com/forums/ubbthreads.php?ubb=showflat&Number=131814&page=18

http://www.mywindpowersystem.com/2009/05/the-most-amazing-wind-turbines-designs/

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Creative Windmill Designs

http://inhabitat.com/energy-ball-by-home-energy/

http://gcaptain.com/the-most-interesting-wind-turbine-designs?3397

http://www.archinect.com/schoolblog/entry.php?id=55756_0_39_0_C

http://www.windturbinepicker.com/vertical-axis-wind-turbines/vertical-axis-wind-turbine-design---windspire-by-mariah-power.html

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Turbine Considerations

LARGE TURBINES:

• Able to deliver electricity at lower cost than smaller turbines, because foundation costs, planning costs, etc. are independent of size

• In areas where it is difficult to find sites, one large turbine on a tall tower uses the wind extremely efficient

SMALL TURBINES:

• Local electrical grids may not be able to handle the large electrical output from a large turbine, so smaller turbines may be more suitable

• High costs for foundations for large turbines may not be economical in some areas

• Landscape considerations http://guidedtour.windpower.org/en/environmentandplanning.htm

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Blade Considerations

• Most common design is the three-bladed turbine

• Provides stability

• A rotor with an even number of blades will give stability problems for a machine with a stiff structure

• At the very moment when the uppermost blade bends backwards, because it gets the maximum power from the wind, the lowermost blade passes into the wind shade in front of the tower

http://apps.carleton.edu/campus/facilities/sustainability/wind_turbine/

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Generators

• Wind power generators convert wind energy (mechanical energy) to electrical energy

• The generator is attached at one end to the wind turbine, which provides the mechanical energy

• At the other end, the generator is connected to the electrical grid

• The generator needs to have a cooling system to make sure there is no overheating

http://www.google.com/imgres?imgurl=http://www.electric.seviervilletn.org/images/diagram_wind.gif

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Costs

• A typical 600 kW turbine costs about $450,000.

• Installation costs are typically $125,000.

• Therefore, the total costs will be about $575,000.

• The average price for large, modern wind farms is around $1,000 per kilowatt electrical power installed.

• Modern wind turbines are designed to work for some 120,000 hours of operation throughout their design lifetime of 20 years. (13.7 years non-stop)

• Maintenance costs are about 1.5-2.0 percent of the original cost, per year.

http://www.artsjournal.com/mt4/mt-search.cgi?IncludeBlogs=47&tag=deaccessioning&limit=20

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US Wind Energy Use

• The U.S. currently has more than 1,600 MW of installed capacity and

produces about 3 billion KWh of electricity each year. • This is enough to meet the annual residential needs of 1 million people.

• More than 90 percent of this power is produced by three wind farms in California (Altamont Pass, Tehachapi and Palm Springs).

http://aumenergy.net/resources

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Facts about Wind Energy

• The U.S. contains enough useable wind resource to produce more electricity than the nation currently uses.

• The majority of this usable resource is in the Great Plains region. North Dakota alone has enough suitable wind resource to supply 36 percent of the electricity consumed in the U.S.

• In addition, development of major global wind energy markets could significantly impact jobs—recent studies show that each billion kilowatt-hours of annual wind energy generation creates between 440 to 460 jobs. http://gotpowered.com/2010/wind-power-

creates-jobs-in-europe/

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Advantages of Wind Power

• The wind blows day and night, which allows windmills to produce electricity throughout the day

• Energy output from a wind turbine will vary as the wind varies, although the most rapid variations will to some extent be compensated for by the inertia of the wind turbine rotor

• Wind energy is a domestic, renewable source of energy that generates no pollution and has little environmental impact

• Up to 95 percent of land used for wind farms can also be used for other profitable activities including ranching, farming and forestry

• The decreasing cost of wind power and the growing interest in renewable energy sources should ensure that wind power will become a viable energy source in the United States and worldwide.

http://www.marketingpilgrim.com/2009/10/google-gives-a-thumbs-up-to-reputation-management.html

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Disadvantages

• Wind variance• Can be noisy • Ugly • Low capacity factor• Wildlife

• Some research suggests that wildlife is not affected and adapts to its surroundings

• Birds will often next on windmills

http://ineedfile.com/archive/birds.html

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Discussion Questions

• What is the benefit of a three blade windmill?

• What are some of the advantages/disadvantages of wind energy?

• What advantages does North Dakota offer for wind energy?

http://blog.salazarpackaging.com/sustainable-people/no-getting-around-%E2%80%9Cgreen%E2%80%9D/

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Resources

www.windpower.org

DPI Prime Facts:http://www.dpi.nsw.gov.au/__data/assets/pdf_file/0010/139951/where-does-the-wind-come-from.pdf

Scientific American. “Where Does Wind Come From”. July 18th, 2005. http://www.scientificamerican.com/article.cfm?id=where-does-wind-come-from

American Wind Energy Association:http://www.awea.org/

Department of Energy:http://www.eere.energy.gov/