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  • That's absolutely right. Since wind turbines are generating its own electricity with wind energy, it can be a good substitute for generators. Unlike generators, wind turbines are silent, cheap and does not have any negative effects on human health and to the environment.
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  1. 1. Wind Generators. Riin Maripuu Kristiina Purga 12c
  2. 2. <ul><li>Humans have been using wind power for at least 5,500 years to propel sailboats and sailing ships, and architects have used wind-driven natural ventilation in buildings since similarly ancient times. Windmilles have been used for irrigation pumping and for milling grain since the 7 th century AD. </li></ul><ul><li>The modern wind power industry began in 1979 with the serial production of wind turbines by Danish manufacturers Kuriant, Vestas, Nordtank, and Bonus. </li></ul><ul><li>These early turbines were small by today's standards, with capacities of 20–30 kW each. </li></ul><ul><li>Since then, they have increased greatly in size, while wind turbine production has expanded to many countries. </li></ul>
  3. 3. Advantages of wind energy <ul><li>Attractive as an alternative to fossil fuels. </li></ul><ul><li>It plentiful, renewable, widely distributed, clean, and produces no greenhouse gas emissions. </li></ul>
  4. 4. <ul><li>Wind turbines locations with constantly high wind speeds bring best return on investment. </li></ul><ul><li>It is not politic to build wind generators to places with wind speed under 6m/s. </li></ul>
  5. 5. <ul><li>A quantitative measure of the wind energy available at any location is called the Wind Power Density (WPD.) </li></ul><ul><li>It is a calculation of the mean annual power available per square meter of swept area of a turbine, and is tabulated for different heights above ground. Calculation of wind power density includes the effect of wind velocity and air density. </li></ul>
  6. 6. <ul><li>There are several wind farms with horizontal turbines in Estonia that belong to different companies and private ownership. Some of the biggest are listed here: </li></ul><ul><li>*Virtsu 1 wind farm *Virtsu 2 wind farm *Pakri wind farm *Paldiski wind farm *Viru-Nigula wind farm *Kunda wind-farm *Sudenai wind farm *Hiiumaa offshore wind farm </li></ul>
  7. 7. <ul><li>Right now there are expansions and developments in the making. </li></ul><ul><li>It is planned for the wind energy power level to increase to 700…2100 MW </li></ul>
  8. 8. Horizontal axis advantages <ul><li>V ariable blade pitch, which gives the turbine blades the optimum angle of attack, so the turbine collects the maximum amount of wind energy for the time of day and season. </li></ul><ul><li>The tall tower base allows access to stronger wind in sites with wind shear. In some wind shear sites, the wind speed can increase by 20% and the power output by 34% for every 10 metres in elevation. </li></ul>
  9. 9. Horizontal axis advantages <ul><li>High efficiency, since the blades always move perpendicular to the wind, receiving power through the whole rotation. </li></ul><ul><li>The face of a horizontal axis blade is struck by the wind at a consistent angle regardless of the position in its rotation. This results in a consistent lateral wind loading over the course of a rotation, reducing vibration and audible noise coupled to the tower or mount. </li></ul>
  10. 10. Horizontal axis disadvantages <ul><li>T he tall towers and blades up to 90 meters long are difficult to transport. Transportation can now amount to 20% of equipment costs. </li></ul><ul><li>Tall HAWTs are difficult to install, needing very tall and expensive cranes and skilled operators. </li></ul><ul><li>Massive tower construction is required to support the heavy blades, gearbox, and generator. </li></ul>
  11. 11. <ul><ul><ul><ul><li>Horizontal axis disadvantages </li></ul></ul></ul></ul><ul><li>Reflections from tall HAWTs may affect side lobes of radar installations creating signal clutter, although filtering can suppress it. </li></ul><ul><li>Their height makes them obtrusively visible across large areas, disrupting the appearance of the landscape and sometimes creating local opposition. </li></ul><ul><li>Downwind variants suffer from fatigue and structural failure caused by turbulence when a blade passes through the tower's wind shadow (for this reason, theA majority of HAWTs use an upwind design, with the rotor facing the wind in front of the tower). </li></ul><ul><li>HAWTs require an additional yaw control mechanism to turn the blades and nacelle toward the wind. </li></ul>
  12. 12. Thank you!