Wind energy brief overview


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Wind energy brief overview

  2. 2.  SIDDIQUE, MD. SHOEB HASSAN (11-19383-2)  CHOWDHURY. MUKIT AHMED (ID 11-19326-2)  RASHID, AUNONNA(10-17618-3)  HASAN, NABIL (10-17830-3)  NAZNEEN, MUNIA (10-17830-3)
  3. 3. Wind energy is a renewable source of energy that occurs in the nature spontaneously and can be harnessed to meet the necessity of power. It is being used from a very early age and the technology of using this energy efficiently is being improved with time. It is often termed as wind power when it is converted to some useful forms to serve human needs of power.
  4. 4. Wind power is the conversion of wind energy into a useful form of energy to meet the need of mechanical and electrical power. To obtain mechanical power we use wind mills, wind pumps etc. When wind energy is converted to electrical power, the machinery used is called wind turbine.
  5. 5. Wind energy has been used for centuries to serve different purposes such as for sailing ships, for irrigation as wind pumps, for grinding crops as wind mills etc. Wind energy became more prominent in 19th century in United States.
  6. 6. Wind is defined as the atmospheric air in motion [2].Differentially absorbed solar radiation by earth’s surface heats up the atmospheric air through convection process and that causes temperature differences in air from place to place. This phenomenon results in air motion.
  7. 7. The basic theory of wind energy is to use the updraft and downdraft of wind [3] to rotate wind turbine and with necessary mechanism this rotation of turbine is used to produce mechanical or electrical power. Main components of a wind energy plant are- wind turbine, generator, control system and necessary mechanism for grid integration etc.
  8. 8. Figure 3: Basic principle of wind energy technology (a-wind mechanism. b- wind electricity generation)
  9. 9. Wind turbine is the most important part in the wind power system. It converts rectilinear flow motion into shaft rotation through rotating air foils. In general, wind turbines are of two types- vertical axis type and horizontal axis type.
  10. 10. Fig 04: Different Parts of Wind Turbine (3)
  11. 11.  Nacelle- contains key components of the wind turbine such as gear box, generator etc.  Tower- carries the nacelle and the rotor. High towers provide higher efficiency  Rotor blades-capture the wind energy and transfer the power to the rotor hub.  Gear box-increases the rotational speed of the shaft for the generator
  12. 12. Not capable of taking advantage of higher wind speeds at higher elevations above the ground.  Savonius wind turbine- ‘s’ shaped, drag type, moves slowly but yields a high torque, prominently used for grinding crops, pumping water etc, not very suitable to be used in electricity generation
  13. 13.  Flapping panel wind turbine- does not depend on the direction of wind.
  14. 14.  Darrieus wind turbines-C shaped rotor blades, “egg beater” appearance. high rotational speed, prominently used in electricity generation plants.
  15. 15.  Very commonly used type of wind turbines  The axis of blade rotation is parallel to the ground  Common types of HAWT are upwind and downwind HAWT’s.
  16. 16. Upwind HAWT-designed to operate with the blades upwind of the tower, Large turbines use a motor mechanism that turns the machine according to the wind direction. In small scale turbine, a tail vane is used to keep the blades facing towards the wind.
  17. 17.  Downwind HAWT-operates in a downwind mode, wind passes the tower before striking the blades, Without a tail vain the machine rotor automatically tracks the wind in a downwind mode.
  18. 18.  Drive train speed  Blade regulation To control drive train speed-  Fixed type system-wind turbine system is directly connected to the main grid.  Variable type control system-involves power electronics, the system indirectly connected to the grid.
  19. 19. To control blade regulation-  Stall type-blade position fixed, angle of attack increases with the wind speed untill stall occurs behind the blade.  Pitch type-blade position is varied with wind speed to actively control low speed shafts to obtain a better power curve
  20. 20.  ‘Lift’ and ‘drag’ force on the turbine blade that causes the rotation  Lift force-rotate upward (clockwise)  Drag force- rotate downward (counter clockwise).  Combined effect-turbine rotation
  21. 21. Figure 7:combined effect of lift and drag force on turbine blade [3]
  22. 22. Depends on-  amount of air,  velocity of the air,  mass of the air and the area of interest (area through which air is passing). Wind power equation-
  23. 23.  An alternative to fossil fuels  Plentiful  Renewable  Clean  No green house gas emissions  Uses a little land  Does not affect environment and natural ecosystem
  24. 24.  Significant variation over shorter time scales.  Higher installation cost  Off shore and on shore wind power plants need maintenance.  Power management techniques such as having excess capacity storage, geographically distributed turbines, dispatch able backing sources, storage such as pumped-storage hydroelectricity etc causes cost and labor.
  25. 25.  As of 2011, Denmark is generating more than a quarter of its electricity from wind and 83 countries around the world are using wind power to supply the electricity grid.  In 2010 wind energy production was over 2.5% of total worldwide electricity usage, and growing rapidly at more than 25% per annum.
  26. 26. Figure 8: current status of top 5 countries using wind energy [5]
  27. 27. Figure 9: Increase in total installation of wind power plants from left side respectively in (a) Africa, (b) Asia [5]
  28. 28. Figure 10: increase in total installation of wind power plants from left side respectively in Europe and Oceania and Pacific [5]
  29. 29.  using higher heights, larger blades  using super conducting magnets  advanced control systems for better wind tracking  site specific designs etc are being conducted to improve the performance if wind power plants.  Grid integration and storage of power  Application of flywheels, compressed air, pumped hydro systems, V2G (vehicle to grid) method  Weather forecasting, wind prediction technology etc are also being considered in the studies.
  30. 30. Wind energy is dependent on the location of installation. It has certain limitations as discussed in previous sections. But, it has the benefit that it does not pollute the environment. So, that day is not very far when wind energy will be playing a major role in meeting our increasing need of electrical power.
  31. 31.  Denis G. shepherd “Historical Development Of Wind Mill”, NASA contractor report 4337, DOE/NASA/5266- 1.  Robert Castellano , “ Alternative Energy Technologies”, p. 26. ISBN 978-2813000767.  Alex Kalmikov, Katherine Dykes, “Wind Power Fundementals”, MIT online lecture notes  Holttinen, Hannele "Design and Operation of Power Systems with Large Amounts of Wind Power" (PDF). IEA Wind Summary Paper, Global Wind Power Conference 18–21 September 2006, Adelaide, Australia.  “World energy report 2013”, published in 12th world Wind Energy Conference and Renewable Energy Exhibition, 3-5 June, Havana, Cuba.