Overview

Wind turbines harness the kinetic energy from the wind by transferring the momentum of the air passing through the wind turbine rotor, into the rotor blades which rotates an electrical generator or "induction generator" housed in its nacelle which in turn, converts the energy of the wind into a useable form of pollution-free power, namely, electricity. The rotor blades are designed on the same principles as an aircraft wing, therefore, offering an efficient airfoil design similar to an aircraft wing, creating an optimal blade geometry necessary to squeeze out the best possible efficiency of turbine technology.

In general, there are two configurations of wind turbines seen today. The most common variation is the horizontal axis wind turbine or HAWT which is also the main focus of SOLAR WIND Canada. The other variation is the vertical axis wind turbine or VAWT. The remaining information pertains to the HAWT only.

In order for the wind turbine to operate, it must be installed on a tower, preferably above any wind obstacles such as buildings, forests or geologic formations. Towers come in a variety of forms from cylindrical free standing steel tubular towers, lattice towers and guyed tubular towers typically for small turbines. The large wind turbines can be found on towers of 60 - 80 meters high at the point of the hub. However, for small wind turbines, towers of 15 - 30 meters are to be expected.

The last remaining components of a wind turbine involve managing the direction of the turbine in relation to wind direction (yaw) and the pitch of the attack of the rotors into the wind dependent upon wind speed. The yaw mechanism ensures that the plane of the rotors are always perpendicular to the direction of the wind. This ensures maximum efficiency of the turbine. The second control mechanism is the pitch angle of the rotors. In the very large commercial tubines, if the power output becomes too high for the turbine to handle for any length of time, the pitch of the rotors turns the blades slightly out of the wind, thus reducing the amount of kinetic energy captured by the rotors. Conversely, the rotors are pitched back into the wind when the power of the wind reduces. The small turbines utilize a number of control mechanisms to protect the turbine from high wind situations, through either "furling" or "freewheeling".

How do Wind Turbines Work?

The most effective means of describing how wind turbines work is through a visual presentation, which in fact exists on the US Department of Energy website. Their entertaining and informative animations do provide enough detail to get one's head wrapped around the concepts of wind power and wind turbines. For your convenience, they are included below.

US Department of Energy - Energy Efficiency and Wind & Hydropower Technologies Program - How Wind Turbines Work - Animation	US Department of Energy - Energy Efficiency and Renewable Energy - Wind Power Animation

For those with a greater desire to learn more on wind turbine technologies and gory conceptual details, return to the menu bar at the top of the screen and click on "Technology" to find a variety of relatively intense subjects on renewable energy technologies.

References

1. American Wind Energy Association. "What Are Vertical-Axis Wind Turbines (VAWTs)?". 1998.
2. Danish Wind Industry Association. " Wind Turbine Design: Basic Load Considerations". Danish Wind Industry Association & www.windpower.org 1997-2003.
3. Great Plains Windustry Project. "Introduction to Wind Energy". Great Plains Windustry Project and Institute for Agriculture and Trade Policy. 2000-2006.
4. US Department of Energy. "How Wind Turbines Work". Great Plains Windustry Project and Institute for Agriculture and Trade Policy. 2000-2006.
5. US Department of Energy. "Wind Power". Great Plains Windustry Project and Institute for Agriculture and Trade Policy. 2000-2006.