Difference between revisions of "Wind Poster"

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Highlights
 
Highlights
−
* How do Wind turbines work?  Very similarly as airplane wings.  When the wind passes over the blade it creates a localized low pressure area behind the blade. The blade is then pulled into this area, causing the rotor to turn.  This is called lift. The push of the wind on the blade is drag. The force of lift is significantly stronger than the drag. The combination of lift and drag cause the rotor to turn and spins the generator creating electricity. In turbines, the blades are connected to a drive shaft that turns a generator that creates electricity.
+
* Wind turbines turn by a combination of lift and drag, very similarly as airplane wings.  When the wind passes over the blade it creates a localized low pressure area behind the blade. The blade is then pulled into this area.  This is called lift. The push of the wind on the blade is drag. The force of lift is significantly stronger than that of drag. The combination of lift and drag cause the rotor to turn and turns a drive shaft. The drive shaft in turn, turns the generator, creating electricity.  
 
* HAWT vs. VAWT
 
* HAWT vs. VAWT
−
** Hawt  - Horizontal Axis Wind Turbine – make up 95% of all wind machines in the world. The blades look like airplane propellers. There can be 1, 2, or 3 blades on a tower.  Most commonplace are 2 or 3 blades because the blades correct torque
+
** Horizontal Axis Wind Turbines, or HAWTs, make up 95% of all wind machines in the world. The blades look like airplane propellers and one, two, or three blades are generally located per tower.  Most commonplace are 2 or 3 blades because the blades balance each other and minimize torque.
−
** VAWT – Vertical Axis Wind Turbines.  Have a much higher strain on rotors. Also can't be placed on higher towers.
+
** Vertical Axis Wind Turbines, VAWT, have much higher strain on rotors because of the guy wires needed to keep it erect. They also can't be placed on higher towers to take advantage of the more stable winds. There are different styles of VAWT, but all experience the same problems.  
−
*** VAWT picture -- http://www.memagazine.org/backissues/jun04/features/apptowind/30topc.jpg
+
*** VAWT picture -- http://www.memagazine.org/backissues/jun04/features/apptowind/30topc.jpg                 HAWT picture -- http://www.bergey.com/images/Excel.CEC.jpg
 +
* Wind Prospecting
 +
** Before a wind farm is set up, prospecting must be done. Anemometers, a device to determine wind speed, are set up to determine the average wind speed.  For a wind turbine to be practice, the general consensus is the average wind speed is greater than 12 mph.
  
 
Power
 
Power
−
* Power available works as a CUBE of the amount of wind present.  In general a site needs to have average wind speeds of over 5m/s (11mph) for cost effective generation.  Stronger less turbulant wind is 30 m above the ground and higher. A single 750-kilowatt (kW) wind turbine, typical of those now being installed in power plants around the world, produces roughly 2 million kilowatt-hours (kWh) of electricity annually
+
* Power available works as a CUBE of the amount of wind present.  In general, a site needs to have average wind speeds of over 5m/s (11mph) for cost effective generation.  Stronger less turbulent wind is 30 m above the ground and higher. A single 750-kilowatt (kW) wind turbine, typical of those now being installed in power plants around the world, produces roughly 2 million kilowatt-hours (kWh) of electricity annually
  
 
Environmental Impact
 
Environmental Impact
−
* Polution
+
* Pollution
−
** Based on the U.S. average fuel mix, approximately 1.5 pounds of CO2 is emitted for every kWh generated. A 750 W Wind turbine can prevent the production of CO2 that 500 acres of forest can absorb. On average, 300 American homes can be powered by a 1kW turbine.
+
** Based on the U.S. average fuel mix, approximately 1.5 pounds of CO2 is emitted for every kW generated. Post production, a wind turbine does not emit CO2.  A 750 watt wind turbine can prevent the production of CO2 from other power plants that 500 acres of forest can absorb. On average, 300 American homes can be powered by a 1kW turbine.  
 
* Noise
 
* Noise
−
** At a distance of 700-1000 ft, an operating wind farm is no louder than the hum of a refridgerator or a moderately quiet room.
+
** At a distance of 700-1000 ft, an operating wind farm is no louder than the hum of a refrigerator or a moderately quiet room. Small turbines generally create more noise than the larger ones, because they have a higher rotational speed of the tip.  More research money has been devoted to decreasing the noise in larger turbines than in smaller turbines.
−
*** Rural night-time background - 20-40 dB
+
 
−
*** Wind farm at 350m           - 35-45 dB
+
{| border="1"
−
*** Car at 40 mph at 100m       - 55 dB
+
| Rural night-time background|| 20-40 dB
−
*** Busy general office         - 60 dB
+
|-
−
*** Jet aircraft at 250m       - 105 dB
+
| Wind farm at 350m|| 35-45 dB
−
** Small turbines generally create more noise than the larger ones, because:
+
|-
−
*** they have a higher rotational speed of the tip
+
| Car at 40 mph at 100m|| 55 dB
−
*** more research money has been devoted to decreasing the noise in larger turbines.
+
|-
 +
| Busy general office|| 60 dB
 +
|-
 +
| Jet aircraft at 250m|| 105 dB
 +
|}
 +
db - decibel
 +
 
 +
 
 
* Bird and Bats
 
* Bird and Bats
−
** The national Audubon Society has recently isssued a statement that wind turbines are not more harmful to bird populations than cars, planes, and other man-made contributions. The National Audubon Society has supported the development of Wind Energy. According to research in the U.S. And Denmark, the leading country in wind energy production, powerlines poses a higher threat to birds than wind turbines.
+
** The National Audubon Society (NAS) has recently issued a statement that wind turbines are less harmful to bird populations than cars, planes, and other man-made contributions. NAS recently supported the development of responsibly located wind turbines for energy production. According to research in the U.S. And Denmark, the leading country in wind energy production, power lines pose a higher threat to birds than wind turbines.  Deaths caused by wind towers and turbines are on the individual level, not population.  Places with high mortality rates are routinely  investigated.
 +
Newer technology has lowered the mortality rate to bats and birds. The single tower instead of a lattice support or guy wires makes collisions with the pole itself less of an issue in HAWTs. Blades are not required to spin as fast as they were twenty years ago and towers spaced farther apart to lower the risk to the avian population.  
  
 
Comparison of Power Plants
 
Comparison of Power Plants
  
−
{| border="1"||    || Wind Energy|| Natural Gas|| Pulverized Coal
+
{| border="1"
 
|-
 
|-
−
! Project Life (years)|| 30|| 30|| 30
+
!   || Wind Energy|| Natural Gas|| Pulverized Coal
 
|-
 
|-
−
! Construction Period (years)|| 0.5|| 1|| 2
+
! Project Life (years)
 +
| 20 (120,000 hours)|| 30|| 30
 +
|-
 +
! Construction Period (years)
 +
| 0.5|| 1|| 2
 
|-  
 
|-  
−
! Plant Size (MW)|| 100|| 500|| 500
+
! Plant Size (MW)
 +
| 100|| 500|| 500
 
|-
 
|-
−
! Average O&M ($/Mwh)|| 15|| 24|| 20
+
! Capacity Factor
 +
| 25%-30% || 23%-57% || 80%
 
|-
 
|-
−
! Variable O&M ($/Mwh)|| 0|| 2.4|| 1.8
+
! Capital Costs ($/kW)
 +
| $1000 || $700-1,200 || $1,070–$1,500
 +
|-
 +
! Average Operation & Maintenance ($/Mwh)
 +
| 15|| 24|| 20
 +
|-
 +
! O&M per kWh
 +
| $.01-.02 || || .04
 +
|-
 +
! Variable O&M ($/Mwh)
 +
| 0|| 2.4|| 1.6-1.8
 +
|-
 +
! Fuel Costs ($/MBtu)
 +
| 0|| 1.79-10|| 1.50
 
|}
 
|}
 +
 +
[http://www.awea.org/pubs/factsheets/EmissionKB.PDF tables of emissions]
 +
 +
* Background
 +
** The earliest known wind turbine is from Persia, the area now known as Iraq, and were of the vertical axis design. Centuries later, Holland perfected the art of harvesting wind with propeller blades on a rotating axis to face the wind.
 +
** Windmills are primarily used to gather water or grind grain. Turbines (or modern windmills) are used to harvest electricity. Early grain grinders were straight forward, with the grinding stone attached to the vertical shaft of the windmill.
 +
 +
 +
* More information
 +
** www.awea.org – American Wind Energy Association
 +
** http://www.eere.energy.gov/RE/wind.html 
 +
** http://lsa.colorado.edu/essence/texts/wind.htm
 +
** http://www.ece.umr.edu/links/power/wind1.htm – pictures
 +
** http://telosnet.com/wind/ - history
 +
** http://windeis.anl.gov/
 +
** http://www.awea.org/faq/vawt.html – general information about VAWTs
 +
** http://www.eere.energy.gov/RE/wind_technologies.html – links to other sites
 +
** http://www.masstech.org/cleanenergy/wind.htm
 +
** (1) http://www.newtonhouse.info/wind.htm
 +
** http://www.eas.asu.edu/~holbert/eee463/ECONOMICS.HTML

Latest revision as of 13:28, 12 August 2005

Highlights

  • Wind turbines turn by a combination of lift and drag, very similarly as airplane wings. When the wind passes over the blade it creates a localized low pressure area behind the blade. The blade is then pulled into this area. This is called lift. The push of the wind on the blade is drag. The force of lift is significantly stronger than that of drag. The combination of lift and drag cause the rotor to turn and turns a drive shaft. The drive shaft in turn, turns the generator, creating electricity.
  • HAWT vs. VAWT
    • Horizontal Axis Wind Turbines, or HAWTs, make up 95% of all wind machines in the world. The blades look like airplane propellers and one, two, or three blades are generally located per tower. Most commonplace are 2 or 3 blades because the blades balance each other and minimize torque.
    • Vertical Axis Wind Turbines, VAWT, have much higher strain on rotors because of the guy wires needed to keep it erect. They also can't be placed on higher towers to take advantage of the more stable winds. There are different styles of VAWT, but all experience the same problems.
  • Wind Prospecting
    • Before a wind farm is set up, prospecting must be done. Anemometers, a device to determine wind speed, are set up to determine the average wind speed. For a wind turbine to be practice, the general consensus is the average wind speed is greater than 12 mph.

Power

  • Power available works as a CUBE of the amount of wind present. In general, a site needs to have average wind speeds of over 5m/s (11mph) for cost effective generation. Stronger less turbulent wind is 30 m above the ground and higher. A single 750-kilowatt (kW) wind turbine, typical of those now being installed in power plants around the world, produces roughly 2 million kilowatt-hours (kWh) of electricity annually

Environmental Impact

  • Pollution
    • Based on the U.S. average fuel mix, approximately 1.5 pounds of CO2 is emitted for every kW generated. Post production, a wind turbine does not emit CO2. A 750 watt wind turbine can prevent the production of CO2 from other power plants that 500 acres of forest can absorb. On average, 300 American homes can be powered by a 1kW turbine.
  • Noise
    • At a distance of 700-1000 ft, an operating wind farm is no louder than the hum of a refrigerator or a moderately quiet room. Small turbines generally create more noise than the larger ones, because they have a higher rotational speed of the tip. More research money has been devoted to decreasing the noise in larger turbines than in smaller turbines.
Rural night-time background 20-40 dB
Wind farm at 350m 35-45 dB
Car at 40 mph at 100m 55 dB
Busy general office 60 dB
Jet aircraft at 250m 105 dB

db - decibel


  • Bird and Bats
    • The National Audubon Society (NAS) has recently issued a statement that wind turbines are less harmful to bird populations than cars, planes, and other man-made contributions. NAS recently supported the development of responsibly located wind turbines for energy production. According to research in the U.S. And Denmark, the leading country in wind energy production, power lines pose a higher threat to birds than wind turbines. Deaths caused by wind towers and turbines are on the individual level, not population. Places with high mortality rates are routinely investigated.

Newer technology has lowered the mortality rate to bats and birds. The single tower instead of a lattice support or guy wires makes collisions with the pole itself less of an issue in HAWTs. Blades are not required to spin as fast as they were twenty years ago and towers spaced farther apart to lower the risk to the avian population.

Comparison of Power Plants

Wind Energy Natural Gas Pulverized Coal
Project Life (years) 20 (120,000 hours) 30 30
Construction Period (years) 0.5 1 2
Plant Size (MW) 100 500 500
Capacity Factor 25%-30% 23%-57% 80%
Capital Costs ($/kW) $1000 $700-1,200 $1,070–$1,500
Average Operation & Maintenance ($/Mwh) 15 24 20
O&M per kWh $.01-.02 .04
Variable O&M ($/Mwh) 0 2.4 1.6-1.8
Fuel Costs ($/MBtu) 0 1.79-10 1.50

tables of emissions

  • Background
    • The earliest known wind turbine is from Persia, the area now known as Iraq, and were of the vertical axis design. Centuries later, Holland perfected the art of harvesting wind with propeller blades on a rotating axis to face the wind.
    • Windmills are primarily used to gather water or grind grain. Turbines (or modern windmills) are used to harvest electricity. Early grain grinders were straight forward, with the grinding stone attached to the vertical shaft of the windmill.


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