Principles by wanghonghx


									It Blows You Away
"Coal, gas and oil will not be the three
 kings of the energy world for ever. It is
 no longer folly to look up to the sun
 and wind, down into the sea's waves"
 Energy is a major input for overall socio-
  economic development of any society

 The prices of the fossil fuels steeply increasing

 So renewables are expected to play a key role

 Wind energy is the fastest growing renewable

 Wind turbines are up to the task of producing
  serious amounts of electricity
Uneven heating of earth’s surface and rotation
                                  Beaufort Scale
Force   Strength          km/h        Effect

0       Calm              0-1         Smoke rises vertically

1       Light air         1-5         Smoke drifts slowly

2       Light breeze      6-11        Wind felt on face; leaves rustle

3       Gentle breeze     12-19       Twigs move; light flag unfurls

4       Moderate breeze   20-29       Dust and paper blown about; small branches move

5       Fresh breeze      30-39       Wavelets on inland water; small trees move

6       Strong breeze     40-50       Large branches sway; umbrellas turn inside out

7       Near gale         51-61       Whole trees sway; difficult to walk against wind

8       Gale              62-74       Twigs break off trees; walking very hard

9       Strong gale       75-87       Chimney pots, roof tiles and branches blown down

10      Storm             88-101      Widespread damage to buildings

11      Violent Storm     102-117     Widespread damage to buildings

12      Hurricane         Over 119    Devastation
Velocity with Height
Power vs. Velocity
Lift and drag forces
Solidity and Tip speed ratio
Performance co-efficient and Betz criterion
 Huge potential exists
   Available potential can contribute five
    times the world energy demand
 0.4% contribution to total energy
Wind is currently the world’s fastest growing energy source
Growth of Wind Energy

Wind Energy generating capacity by country, 1980-2003
Installed Capacity (MW) in 2005
Available potential in India
Wind Power Density of India
All India Fuel wise Installed Capacity, 2004
State wise potential in India, 2005
  Turbine Evolution
             Used for
                   • Pumping water
                   • Grinding grain

Mainly used for
      • Generating Electricity
          Types of turbines
  Drag is the main force

  Nacelle is placed at the bottom

  Yaw mechanism is not required

  Lower starting torque

  Difficulty in mounting the turbine

  Unwanted fluctuations in the power output
  Lift is the main force

  Much lower cyclic stresses

  95% of the existing turbines are HAWTs

  Nacelle is placed at the top of the tower

  Yaw mechanism is required
    Two types of HAWT

Counter Rotating HAWT

   Increase the rotation speed

   Rear one is smaller and stalls at high
   wind speeds

   Operates for wider range of wind speeds
        Offshore turbines
 More wind speeds

 Less noise pollution

 Less visual impact

 Difficult to install and maintain

 Energy losses due long distance
A Typical HAWT
Turbine design and construction

   Blades

     Material used

     Typical length

   Tower height

     Heights twice the blade length are
      found economical
 Number of blades
   Three blade HAWT are most efficient

   Two blade turbines don’t require a hub

   As the number increases; noise, wear and
    cost increase and efficiency decreases

   Multiple blade turbines are generally used
    for water pumping purposes
 Rotational control
   Maintenance

   Noise reduction

   Centripetal force reduction

   Mechanisms
      Stalling

      Furling
 Yaw Mechanism
   To turn the turbine against the wind
   Yaw error and fatigue loads
   Uses electric motors and gear boxes
 Wind turbine safety
   Sensors – controlling vibrations
   Over speed protection
      Aero dynamic braking
      Mechanical braking
 Concentrators
Future Wind Turbines
Wind Amplified Rotor Platform
       Disc type wind turbine

o Much more efficient than

o Requires less height

o Low noise

o Works in any wind direction
        Determining Factors

 Wind Speed

 Turbine design and construction

 Rated capacity of the turbine

 Exact Location

 Improvements in turbine design

 Capital
Wind Speed Matters

              the same
              size project,
              the better
              the wind
              the lower
              the cost.
Size Matters

          Assuming the
          same wind
          speed of 8.08
          m/s, a large
          wind farm is
Overall cost distribution
Break down of capital cost
             Energy Cost Trend

 1979: 40 cents/kWh

                  4 - 6 cents/kWh

 Increased
  Turbine Size
 R&D Advances
 Manufacturing                3 – 4.5 cents/kWh
       Typical cost statistics
 Size: 51 MW
 Wind Speed: 13-18 miles/hour

 Capital cost: $ 65 million ($1300/MW)

 Annual production: 150 million kW-hr

 Electricity costs: 3.6-4.5 cents

 Payback period: 20 years
Economic Advantages
 Greater fuel diversity
 No delay in construction
 Low maintenance costs
 Reliable and durable equipment
 Additional income to land owners
 More jobs per unit energy produced
 No hidden costs
Wind Capital Cost
Cost of Wind Energy
       Germany now and 2020
 At present 10%
  of the country’s
  energy is
  supplied by wind
 By 2020 it is
  expected to go up
  to 26%
Australia now and 2040

 Price of wind power is coming down
 There is enormous capacity

 Energy storage, however, is still a problem
Typical Concerns
 Visual impact
      Off shore turbines
      Arrangement

 Avian concerns
      Suitable choice of site
      Using tubular towers instead of lattice tower
      Using radars
 Noise
   Varies as 5th power of relative wind speed
   Streamlining of tower and nacelle
   Acoustic insulation of nacelle
   Specially designed gear box
   Use of upwind turbines
   Reducing angle of attack
   Low tip speed ratios
 Changes in wind patterns
   Reducing turbulence
 Intermittent
   Coupling with hydro or solar energy
 TV, microwave, radar interference
   Switching from conducting material to
    non-conducting and composite material
 Wind energy is pollution free and nature
 Wind energy has very good potential and it is
  the fastest growing energy source
 The future looks bright for wind energy
  because technology is becoming more
  advanced and windmills are becoming more

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