Wind Energy: The New Alternative

1
Wind Energy The New Alternative

• By James Washechek
• Department of Chemical Engineering,
• The University of Texas at Austin

2
Description of Wind Turbines

• Converts wind kinetic energy into electrical
  power
• Numerous industrial turbine designs, for example
  horizontal and vertical axis wind turbines
• Clean energy alternative, with little to no
  environmental impact
• Affects environmental aesthetic integrity, some
  migratory bird patterns, and downwind wind
  velocity.

3
History of Wind Powered Turbines

• 200 B.C. Wind powered machines utilized by
  Persians.
• 1888 Charles F. Brush developed first energy
  producing windmill in Cleveland, Ohio.
• 1980s - First modern wind turbines were
  constructed.
• Past 20 years Newer, better designed wind
  turbines have been developed.

4
Future Wind Energy Capacity

• Increasing exponentially
• 3 to 5 times larger energy capacity over next 6
  years
• 20 of electrical energy supplied by wind energy
  by 2030

World Wind Energy Capacity Approximation (Wiki,
2008)
5
Turbine Power

• Directly proportional to density of air, area of
  rotor blades, and cube of velocity
• Efficiency of internal parts affects maximum
  power available
• Limited to 59 maximum efficiency

where, P power (W) a design efficiency
factor ? density of air (kg/m³) r
radius of wind turbine (m) v velocity of
wind (m/s)
6
Comparisons to Other Energy Sources

• Environmentally friendly
• Large resource supply
• Cheap operating costs, 1cent/kWhr
• Wind 55.80/MWh
• Coal 53.10/MWh Natural Gas 52.50/MWh

Wind
vs.
Coal
Natural Gas
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Horizontal Axis Wind Turbine (HAWT)

• Most common industrial design today
• Wind sensors to rotate tower in yaw direction
• Many found in West Texas where wind velocities
  are high

Horizontal Axis Wind Turbine Design
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HAWT Advantages and Disadvantages

• Advantages

• Disadvantages

• Variable wind pitch to optimize amount of wind
  absorbed.
• Able to increase height of tower to harness
  higher wind velocities at higher altitudes.
• Already the major design for industrial wind
  power generation.

• Inefficient close to ground level due to
  turbulence
• Must be large scale making expensive construction
  costs
• Must be comprised of strong materials (carbon
  fiber and steel) to deal with high winds

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Vertical Axis Wind Turbine (VAWT)

• Gearbox and generator at base of vertical rotor
  shaft.
• Utilizes wind flow in all directions (360).
• Constructed on buildings to avoid ground level
  turbulence.

Vertical Axis Wind Turbine Design
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VAWT Advantages and Disadvantages

• Advantages

• Disadvantages

• Cheaper due to less height needed for effective
  operation.
• No motor is needed to turn rotor blades.
• Routine maintenance easy due to components being
  situated under vertical rotor shaft
• Little chance of structural failure

• Create only half the amount of energy of a
  comparable HAWT
• Cannot harness higher winds at higher altitudes
  due to smaller height.
• Complete deconstruction for maintenance.

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Conclusions

• Horizontal axis wind turbine the preferred design
  for future industrial use.
• Future efforts in wind energy technology.
• Combination of wind energy with current energy
  infrastructure.

Airborne Wind Generator
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References

• Hansen, Martin O.L. Aerodynamics of Wind
  Turbines, 2nd Ed. Earthscan Publications Ltd,
  January 2008.
•  
• Hau, Erich and H. von Renouard. Wind Turbines
  Fundamentals, Technologies, Application,
  Economics, 2nd Ed. Springer, October 1, 2005.
•  
• McCabe, W.L. and J.C. Smith. Unit Operations of
  Chemical Engineering, 7th Ed. McGraw-Hill, New
  York.
•  
• Ragheb, M. Theory of Wind Machines, Betz
  Equation. 16 Nov. 2008 lthttps//netfiles.uiuc.ed
  u/mragheb/www/NPRE20498WP20 Wind20Power20Syste
  ms/Theory20of20Wind20Machin es20Betz20Equatio
  n..pdfgt.
•  
• "Wind Power." Wikipedia The Free Encyclopedia.
  10 Nov. 2008 lthttp//en.wikipedia.org/wiki/Wind_p
  owergt.
•  
• "Wind Turbine." Wikipedia The Free Encyclopedia.
  17 Nov. 2008 lthttp//en.wikipedia.org/wiki/Wind_t
  urbinegt.