Solar Energy IIISolar Energy III

Wind Power. Wind Power.

Would you like to see and increase in Would you like to see and increase in wind power production?wind power production?

1 2

50%50%1.1. YesYes

2.2. NoNo

Which statement best captures your opinion Which statement best captures your opinion of the appearance of wind farms?of the appearance of wind farms?

1 2 3 4

25% 25%25%25%1.1. They are a blight They are a blight on the landscapeon the landscape

2.2. I don’t really I don’t really notice themnotice them

3.3. They are really They are really cool looking.cool looking.

4.4. By day they are By day they are fine, but I hate the fine, but I hate the lights at nightlights at night

Approximately 2% of the solar power Approximately 2% of the solar power that reaches the earth’s surface is that reaches the earth’s surface is converted into wind.converted into wind.

This is ~30 times our present energy This is ~30 times our present energy usage.usage.

HistoryHistory

Large sailing ships Large sailing ships could generate 10,000 could generate 10,000 hp.hp.

Used extensively in Used extensively in Europe in the 19Europe in the 19thth century century

Used for pumping Used for pumping water in the US.water in the US.

Most new Most new development for development for generating electricitygenerating electricity

Early wind Early wind generators focused generators focused on single large on single large generatorsgenerators

Grandpa’s Knob Grandpa’s Knob (Vermont) could (Vermont) could generate up to 1.2 generate up to 1.2 MW of power in the MW of power in the 1940’s.1940’s.

200 ft diameter 200 ft diameter bladesblades

New interest in New interest in wind electricity wind electricity after oil embargo after oil embargo in 1973.in 1973.

Early NASA wind Early NASA wind generator (1975) generator (1975) could generate could generate 100kW of power in 100kW of power in 18mph wind. 125 ft 18mph wind. 125 ft long blade long blade diameter.diameter.

Boeing Mod 5B Boeing Mod 5B wind turbine on wind turbine on Oahu could Oahu could generate 3.2 MW of generate 3.2 MW of electricity.electricity.

320 ft diameter on 320 ft diameter on a 192 ft tall towera 192 ft tall tower

Many Different StylesMany Different Styles

Savonius Rotor

Darius Rotor

American multivane

2-Blade Wind Turbine

3-Blade Wind Turbine

Choice of style depends on Choice of style depends on applicationapplication

Multi-blade has good starting torque. Multi-blade has good starting torque. Good for applications like pumps.Good for applications like pumps.

3-blade has low starting torque but is 3-blade has low starting torque but is more efficient at high rotation rates. more efficient at high rotation rates. Used for generating electricityUsed for generating electricity

Wind FarmsWind Farms

Rather than using Rather than using single large single large generator, we generator, we usually use several usually use several smaller generators smaller generators to make wind to make wind farmsfarms

PracticalitiesPracticalities

Wind speed tends to increase with Wind speed tends to increase with increasing height. Optimal height is increasing height. Optimal height is ~300 m. ~300 m.

Most commercial wind mill towers Most commercial wind mill towers are ~50m high. Get ~80% of wind are ~50m high. Get ~80% of wind potential at this height.potential at this height.

Power in the windPower in the wind(Betz Limit)(Betz Limit)

P=2.83P=2.831010-4 -4 DD22vv3 3 kWkW

D is the diameter in metersD is the diameter in metersV is the wind speed in meters per V is the wind speed in meters per

secondsecond

D2 because area of windmill increase with D2

V3 because KE in wind is proportional to v2 and an additional v because of rate at which energy is brought to windmill

Maximum theoretical efficiency is Maximum theoretical efficiency is 59% of the Betz limit. 59% of the Betz limit.

Modern windmills are around 50-70% Modern windmills are around 50-70% of maximum theoretical efficiencyof maximum theoretical efficiency

Note vNote v3 3 indicates that a wind of 15 indicates that a wind of 15 miles per hour generates 3miles per hour generates 333=27 =27 times as much power as a wind of 5 times as much power as a wind of 5 miles per hour.miles per hour.

You want to place windmills in a You want to place windmills in a location that get consistently high location that get consistently high wind powerwind power

Real windmills get 50-70% of this

Average Wind Speed at 80 mAverage Wind Speed at 80 m

US Power GridUS Power Grid

Rated OutputRated Output

A wind generator has a rated power A wind generator has a rated power output a a particular wind speed, e.g. output a a particular wind speed, e.g. 10 kW at 20 mph.10 kW at 20 mph.

If wind speed drops so does power, If wind speed drops so does power, e.g. if wind drops to 15mph, e.g. if wind drops to 15mph, P=(15/20)P=(15/20)33 10kW = 4.2kW. 10kW = 4.2kW.

If wind speed increases too much, If wind speed increases too much, usually feather the blades so they usually feather the blades so they don’t get damaged.don’t get damaged.

Home Wind Power?Home Wind Power? HORNET - LOW WIND SPEED HORNET - LOW WIND SPEED

turbines with turbines with Split-Core PMA PMA     Hornet's are designed for Hornet's are designed for

class 3 to 7class 3 to 7 or AVERAGE or AVERAGE wind zones..    

Super low cost turbines!Super low cost turbines!     59" diameter blade59" diameter blade     800 Watts @ 33 MPH800 Watts @ 33 MPH

1200 Watts MAX. @ 65 MPH 1200 Watts MAX. @ 65 MPH (under load)(under load)

~$500.00~$500.00 Note at 11mph P=800/27=30WNote at 11mph P=800/27=30W  

States with more than 2000MW of States with more than 2000MW of Installed Wind Capacity (2010)Installed Wind Capacity (2010)

State Installed Wind Capacity (2010) (MW)

Texas 10085

Iowa 3675

California 3177

Minnesota 2192

Washington 2104

Oregon 2104

Illinois 2046

Installed Wind CapacityInstalled Wind Capacity

Concerns About Wind PowerConcerns About Wind Power Wind is intermittent so you don’t want to Wind is intermittent so you don’t want to

rely on it too much. ~15-20% is considered rely on it too much. ~15-20% is considered safe.safe.

Aesthetics: Actually more opposed to by Aesthetics: Actually more opposed to by people who don’t live near them.people who don’t live near them.

Noise: New designs are very quietNoise: New designs are very quiet Danger to birds and bats. Needs more Danger to birds and bats. Needs more

study.study. Potential electromagnetic disturbance for Potential electromagnetic disturbance for

TV/ RadioTV/ Radio

Potential SolutionsPotential Solutions Use large scale batteries to even out Use large scale batteries to even out

supply.supply. Research on Vanadium Redox Research on Vanadium Redox

batteries.batteries. Mid scale test facility is being Mid scale test facility is being

constructed.constructed.

Pro-Wind Site EstimatesPro-Wind Site Estimates

Man-made structure/technology

Associated bird deaths per year in US (Source)

Feral and domestic cats Hundreds of millions (AWEA)

Power lines 130-174 million (AWEA)

Windows (residential and commercial

100 million-1billion (TreeHugger)

Pesticides 70 million (AWEA)

Automobiles 60-80 million (AWEA)

Light communication towers 40-50 million (AWEA)

Wind turbines 10-40 thousand (ABC)

Help for the birdsHelp for the birds

Site their farms mostly on land that's already Site their farms mostly on land that's already disturbed (I.e. farmland.) Also, keeping them out disturbed (I.e. farmland.) Also, keeping them out of migratory flight paths will reduce the threat.of migratory flight paths will reduce the threat.

• • Make the transmission lines that connect to Make the transmission lines that connect to wind farms more bird-friendlywind farms more bird-friendly

• • Monitor the impact of wind farms on birds.Monitor the impact of wind farms on birds. • • Compensate the families of affected birds by Compensate the families of affected birds by

buying land to be set aside as bird habitat.buying land to be set aside as bird habitat. Paint wind turbines anything but whitePaint wind turbines anything but white Bird hit by turbine

AdvantagesAdvantages

RenewableRenewable NO CONO CO22 emissions emissions Competitive price per kW-hCompetitive price per kW-h Less than 1% of the land would be Less than 1% of the land would be

used for foundations and access used for foundations and access roads, the other 99% could still be roads, the other 99% could still be used for farming. used for farming.