today windmill

Today's Windmill

Sustainable Wind Power

Wind Turbine

A wind turbine is a windmill-like structure specifically developed to generate electricity. They are seen as the next step in the development of the windmill. In recent years, wind energy has become one of the most economical renewable energy technology in current society. Today, electricity-generating wind turbines employ proven and tested technology and provide a secure and sustainable energy supply. Under most circumstances, wind energy can already successfully compete with conventional energy production at good and windy sites. 

Wind turbines work on a simple principle: instead of using electricity to make wind, wind turbines use the wind to make electricity. The wind turns the propeller-like blades of a turbine around a rotor, which spins a generator, to create electricity.

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Types of Wind Turbines

Horizontal axis wind turbines dominate the majority of the wind industry. Horizontal axis means the rotating axis of the wind turbine is horizontal, or parallel with the ground. They have three blades and operate “upwind,” with the turbine pivoting at the top of the tower so the blades face into the wind.

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Vertical-axis wind turbines come in several varieties, including the eggbeater-style Darrieus model, named after its French inventor. Since these turbines are omnidirectional, they don’t need to be adjusted to point into the wind to operate. They are more widely used in small wind and residential wind applications.

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How Does a Wind Turbine Work?

The inner mechanical structure of a wind turbine is complex. Different essential components work together to generate electricity from wind energy:

The working principle of wind turbine

  1. Blades: Lifts and rotates when the wind is blown over them, causing the rotor to spin. Most turbines have either two or three blades.
  2. Rotor: Blades and hub together form the rotor.
  3. Low-speed shaft: Turns the low-speed shaft at about 30-60 rpm.
  4. Gear Box: Connects the low-speed shaft to the high-speed shaft and increases the rotational speeds from about 30-60 rotations per minute (rpm) to about 1,000-1,800 rpm; this is the rotational speed required by most generators to produce electricity.
  5. High-speed shaft: Drives the generator.
  6. Generator: Produces 60-cycle AC electricity; it is usually an off-the-shelf induction generator.
  7. Anemometer: Measures the wind speed and transmits wind speed data to the controller.
  8. Controller: Starts up the machine at wind speeds of about 8 to 16 miles per hour (mph) and shuts off the machine at about 55 mph. Turbines do not operate at wind speeds above about 55 mph because they may be damaged by the high winds.
  9. Pitch system: Turns (or pitches) blades out of the wind to control the rotor speed, and to keep the rotor from turning in winds that are too high or too low to produce electricity.
  10. Brake: Stops the rotor mechanically, electrically, or hydraulically, in emergencies.
  11. Wind vane: Measures wind direction and communicate with the yaw drive to orient the turbine properly with respect to the wind.
  12. Yaw drive: Orients upwind turbines to keep them facing the wind when the direction changes. Downwind turbines don’t require a yaw drive because the wind manually blows the rotor away from it.
  13. Yaw Motor: Powers the yaw drive.
  14. Tower: Made from tubular steel (shown here), concrete, or steel lattice. Supports the structure of the turbine. Because wind speed increases with height, taller towers enable turbines to capture more energy and generate more electricity.
  15. Nacelle: Sits atop the tower and contains the gearbox, low- and high-speed shafts, generator, controller, and brake. Some nacelles are large enough for a helicopter to land on.

Summarized from the carton shown in the link:

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Pros vs. Cons of Wind Energy

  1. Clean fuel source: unlike the traditional source of energy, such as coal or natural gas, which emit carbon dioxides, nitrogen oxides, sulfur dioxide, and other greenhouse gases to the atmosphere, wind power does not pollute the air.
  2. Sustainability: Since winds are caused by the heating of the atmosphere by the sun, the rotation of the Earth, and the Earth’s surface irregularities, wind power can be gained as long as the sun shines and the wind blows. 
  3. Cost-effective: costing 1–2 cents/kWh after the production tax credit, wind turbine utility is one of the lowest-priced energy sources available today.
  4. Creating jobs: today, more than 100,000 workers are hired in the wind energy area in the U.S., and wind turbine engineer is one of the fastest-growing American jobs.
  5. Can be built on existing farms or ranches: Farmers and ranchers can continue to work the land because the wind turbines use only a fraction of their land. This greatly benefits the economy in rural areas.


  1. Inconsistent source: It is necessary to carefully choose the optimal location for setting up turbines before actual installation because wind speeds fluctuate every day.
  2. Hight initial investment: the entire process, such as manufacturing and transportation to the site,
  3. Negative visual impact: the performance of wind turbines impacts the natural beauty of the landscape.
  4. Noise disturbance: the sound produced by one wind turbine can be perceived from far distances
  5. Damage to the ecological impacts: the construction of wind turbines destroys the habitats of flying and marine animals.



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  1. Storrow, B. (2019, August 05). Giant Turbines Propel Boom in Wind Energy. Retrieved from
  2. Shackleton, Jonathan. “World First for Scotland Gives Engineering Student a History Lesson”. The Robert Gordon University. 
  3. Advantages and Challenges of Wind Energy.   Retrieved from
  4. Pros and Cons of Wind Energy (Wind Power). (2020, August 04). 7  Retrieved from
  5. How Do Wind Turbines Work? Retrieved from


Lingkun Chen, Undergraduate Student
Fall 2020