​How does a Wind Energy Converter (WEC) Produce Electricity?


Wind turbines are devices that convert the winds kinetic energy into electrical energy. Wind can easily be explained as moving air that is caused by atmospheric pressure and changes with temperature. Like other renewables, there are some locations better suited for wind energy generation than others. There are optimal wind turbine locations both on and offshore 

So, what exactly are those gigantic windmills called wind turbines? A wind turbine is a large structure with several spinning blades, usually three. A wind turbine turns wind energy into electricity using the aerodynamic force from the rotor blades, which work like an airplane wing or helicopter rotor blade. Wind turbine blades rotate when hit by the wind and are connected to a shaft and rotor at the top of the turbine. The shaft is connected to a generator that generates electricity when the wind causes the blades to spin. Electricity generated by wind turbines may be used locally right away or placed on the electric grid to power homes and businesses farther away. 

A wind turbine turns wind energy into electricity using the aerodynamic force from the rotor blades, which work like an airplane wing or helicopter rotor blade.

men in front of windmill in field

Modern wind turbines fall into two basic groups, vertical axis wind turbines, and the horizontal axis wind turbines.  

wind farm in field

HORIZONTAL-AXIS TURBINES:  

Horizontal axis wind turbines dominate the majority of the wind industry and are what many people picture when thinking of wind turbines. Most commonly, they have three blades and operate "upwind," with the turbine pivoting at the top of the tower so the blades face into the wind. The advantage of horizontal wind is that it can produce more electricity from a given amount of wind. So, if you are trying to produce as much wind as possible at all times, horizontal axis is likely the choice for you. 

 

VERTICAL-AXIS TURBINES: 

Vertical-axis wind turbines come in several varieties. These turbines are omnidirectional, meaning they don’t need to be adjusted to point into the wind to operate. Vertical axis turbines are primarily used in small wind projects and residential applications. Vertical axis turbines are powered by the wind coming from all 360 degrees, and even some turbines are powered when the wind blows from top to bottom. Because of this versatility, vertical axis wind turbines are thought to be ideal for installations where wind conditions are not consistent, or due to public ordinances, the turbine cannot be placed high enough to benefit from steady wind. 

The advantage of horizontal wind is that it can produce more electricity from a given amount of wind. So, if you are trying to produce as much wind as possible at all times, horizontal axis is likely the choice for you. 

Components of a Wind Turbine

  • Tower: The base structure that supports and elevates a wind turbine rotor and nacelle. 
  • 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. 
  • Blades: Lifts and rotates when the wind is blown over them, causing the rotor to spin. Most turbines have either two or three blades. 
  • Hub: The center of a turbine rotor, which holds the blades in place and attaches to the shaft. The rotor refers to both the turbine blades and the hub. 
  • Gearbox: Gears connect the low-speed shaft to the high-speed shaft and increase the rotational speed of the shaft to the speed required by the generator. The gearbox is heavy and power losses from friction are inherent in any gearing system. 
  •  Generator: A device that produces electricity from mechanical energy, such as from a rotating turbine shaft. 

​Energy Production and Efficiency

When many people think of wind turbines, they may imagine small machines behind someone’s house. However, industrial wind turbines are massive pieces of technology with blades that can easily span hundreds of feet. The average size of wind turbines varies and increases as technology improves. Canada finished 2019 with 13,413 MW of installed energy capacity - enough to power approximately 3.4 million homes. The year saw the completion of five projects that added 597 MW of new installed capacity, representing over $1 billion of investment. Canada is home to the world's eighth-largest wind generating fleet. The theoretical maximum efficiency of a turbine is ~59%, also known as the Betz Limit. Most turbines extract about 50% of the energy from the wind that passes through the rotor area. It is important to remember that windmills generate absolutely zero harmful emissions or greenhouse gases.  

Canada is home to the world's eighth-largest wind generating fleet, and finished 2019 with 13,413 MW of installed energy capacity - enough to power approximately 3.4 million homes.

About the Author

Gerry is from New Glasgow, Nova Scotia and studied at Acadia University graduating with a Certificate of Applied Sciences and Dalhousie University graduating with a Bachelor of Engineering in Environmental Engineering.  


At Dalhousie he became interested in the renewable energy industry and upon graduation was part of the Clean Leadership Professional Internship Program with Naveco. His goal is to assist communities transition from fossil fuels to renewable energy.


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