Wind Energy

DeWind 2MW wind turbine in Veladero mine, Argentina. Image by Fedealvarado.

DeWind 2MW wind turbine in Veladero mine, Argentina. Image by Fedealvarado. License: GNU FDL

Wind energy ultimately comes from the Sun as uneven heating and cooling of the land and water of Earth produces the wind. While it is sunny on one side of the Earth it is dark on the other. Similarly it is hotter on one side and colder on the other. Differences in thermal properties between land and water also create localized wind in addition to this effect from oceans and land. This imbalance of heating causes the winds as the atmosphere attempts to equalize temperatures. Wind energy is also responsible for a form of hydroelectricity, wave power, since it causes the waves.

Uses of Wind Energy

Wind energy has been used for hundreds of years in the form of wind mills and sail boats. It’s only recently that modern use has couple the concept of wind mills with electrical generators to produce wind power farms. Many recreational activities also make use wind energy such as kites, hang gliding, and surfing. Other renewable energy sources also make use of wind energy indirectly to generate electricity such as wave power.

Wind Energy Technology

A 12 ton wind turbine gearbox and brake assembly. Image by Paul Anderson.

A 12 ton wind turbine gearbox and brake assembly. Image by Paul Anderson. License: CC BY-SA 2.0

There are two primary types of wind turbine used for generating electricity. HAWT (Horizontal Axis Wind Turbine) and VAWT (Vertical Axis Wind Turbine). Since HAWTs house their generator up the tower the rotor can be much higher than in VAWT systems where the generator remains on the ground. This higher rotor placement ensures more efficient operation as wind speeds get higher with altitude as well. Wind farms try to maximize efficiency and so primarily use HAWT systems.

Both HAWT and VAWT technology have essentially the same components they are just arranged differently. Wind turbines have blades which attach to a hub creating the rotor. This rotor is attached to a low speed shaft which connects to a gearbox that speeds up the rotation outputting it to a high speed shaft. This increase in rotational speed is done due to the demands of the electrical grid. Slow rotation couldn’t power a generator enough to add electricity to the grid. High speed shaft enters the generator which is connected to the electricity grid, battery bank, etc.

Additionally wind turbines have braking systems to stop the turbine in low wind speeds (otherwise the system would draw power from the grid to turn the blades), control systems to monitor safety and optimise performance, a tower and housing (nacelle) for the components, and wind monitoring equipment like anemometers and wind vanes that connect to the control system.

Environmental Impact of Wind Energy

Savi's Pipistrelle bat killed at "Vjetroelektrana Ravna 1" wind farm in Pag, Croatia. Image by Ana Jancar.

Savi's Pipistrelle bat killed at "Vjetroelektrana Ravna 1" wind farm in Pag, Croatia. Image by Ana Jancar. License: CC BY-SA 3.0

Most of the environmental impact from wind energy is localized to the community where wind farms are placed. Carbon dioxide and other pollutants are only released as byproducts during manufacturing of wind turbine components. Carbon “payback” period is around 9 months meaning operation for 9 months is needed to offset more carbon than is consumed during production. With an average lifespan of over 20 years this is easily obtainable. Poor siting of wind farms in peat bogs, wet lands, and other ecologically and carbon dense biospheres can cause more damage than a project may offset.

Wind Energy in the News

I&M to announce wind farm deal soon – 2013-06-08
MUNCIE Randolph County is in the running, but not Delaware County, for a wind farm or wind farms that would sell electricity to Indiana …
Wind Power Blowing Strong In Cold Climates – 2013-06-08
This deployment is so significant that 4050 GW of wind power capacity (wind turbines, basically) is forecast to be constructed by 2017.
Google Gobbles Up Entire Output Of New Swedish Wind Farm – 2013-06-08
The renewable energy world was abuzz last week with news that Google has just nailed down an exclusive agreement with a Swedish wind …
Wind power is doing well, but it still relies on irregular and short-term … – 2013-06-07
But as the bus travelled across the open plains it was difficult not to notice a new phenomenon in Kansan energy: wind turbines. Lots of them.
Rain, wind energy stave off power crisis – 2013-06-07
Chennai: Thanks to southwest monsoon and wind power generation, Tamil Nadu remains a power surplus state at times. Due to sporadic rains …
AEP Will Invest in Wind Power, Energy Efficiency Under Proposed … – 2013-06-07
Under the terms of a tentative agreement, Kentucky Power will invest heavily in energy efficiency improvements in Eastern Kentucky, and …
Wind farms are a ‘complete scam’, claims the Environment Secretary … – 2013-06-07
Wind farms have been branded a ‘complete scam’ by Environment Secretary Owen Paterson, reigniting coalition battle over green power.
Wind power is cost effective – 2013-06-07
A recent column (Tilting at Hoosier windmills, the external costs May 30) raised important questions regarding the true costs of our electricity …
UK to Share More Wind-Power Wealth With Local Residents – 2013-06-07
The U.K. will give residents more say over onshore wind farms and higher payments to communities affected by them, an effort to heal a rift over …
The U-turn on wind turbines won’t stop their march over every hill … – 2013-06-07
There is no room for more wind turbines on the uplands of Britain. There are too many lobbyists fighting for money. Thursday’s mild government …


  1. carlos lopez says:

    I would like to know more about renewable energy, specifically about small wind turbines in th US.
    I really appreciate any comments

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