Wind Turbine Generators

wind-turbine-generatorsThe first introduction most of us have to harnessing the power of the wind is through the iconic image of a windmill on a rural property.  Most likely, that wind mill was used to pump water from a well to provide irrigation and drinking water for the farming family.

Things have changed!

Green living is an important issue for me and so is our independence from other methods of creating, delivering, and using other sources of energy. Two additional issues that I believe are on most everyone’s mind are financial stability and reducing all possible costs.

I found that installing a wind turbine was not only green, but a very realistic option worth my consideration. This option allowed me to generate my own energy, as well as drastically cut my energy bills.

As you may have guessed, this is a VERY complicated topic.  What follows should be enough to get you pointed in the right direction, and help you make a decision that will increase your personal independence.  More research on your part will definitely be needed!

You should also know that wind energy does not come cheaply, at least at first.  My small system cost several thousand dollars, but is guaranteed for 20 years.  I’ve calculated my “pay back period” to be around 5 years.  The installation company projected around 3 1/2 years, but that was a bit optimistic once the system was actually in use!

How Wind Generators Work

Wind turbines function on an extremely simple principle. They generally have two or three blades, much like a propeller, that are turned by the wind.

A rotor, which is connected to the main shaft, spins the generator to produce energy. A tower is used to mount the turbine for the collection of most of this energy. Wind turbines are usually mounted about 25 feet, or more, above the ground.

For homesteads, this can be as much as 100 feet or more. This is because greater height makes it easier for them to access wind that moves quicker, and is less turbulent.

Many individuals do not realize that the wind method of energy production actually begins with the sun. The sun heats up a portion of land and the land then absorbs some of this heat. When it reaches a certain temperature, the air quickly starts to rise.  When the lighter, hotter air swiftly rises, cooler air moves quickly to fill in the gap left behind by the hot air. That quick moving air is wind.

Types of Wind Turbines

There are two basic types of wind turbines. One is the Horizontal Axis Wind Turbine or HAWT. The other is the Vertical Axis Wind Turbine or VAWT.

The HAWT is most similar to a windmill and the propeller like blades spin on a horizontal axis. The VAWT has the main rotor shaft in a vertical arrangement. This is a large advantage in areas where the wind is very turbulent or highly variable, as it does not require being pointed directly into the wind.

There are four materials generally used in the construction of wind turbine blades which includes wood, PVC, aluminum and fiberglass.

Wooden Blades

• The greatest advantages of wooden blades are that they are lightweight, customizable, and low cost.
• Some disadvantages of wooden turbine blades are that these are temperature and weather sensitive. This type also requires at least some experience and time to shape. They have limited resilience in strong winds.

PVC Blades

• The benefits of PVC blades are they are lightweight, flexible and relatively inexpensive.
• PVC has a few disadvantages as well. It degrades rather quickly when exposed to elements, especially direct sunlight. The blades can also get “floppy” and not provide sufficient force to power the system.

Fiberglass Blades

• The largest advantages of fiberglass wind turbine blades, commercially speaking, are that they are widely accessible and affordable.
• Fiberglass blades are generally not constructed with quality in mind. This type of blade is also extremely vulnerable to cracking and breaking.

Aluminum Blades

• Aluminum blades are thought to be durable however, they do require maintenance. They are widely available and can sustain up to 75 mile per hour winds.
• Aluminum is generally heavier than other forms of synthetic material, which limits the diameter/size.

Key Components of a Wind Turbine

There are four key components of a wind turbine which includes the tower, the base, the blades and the nacelle.

The tower houses the electric conduits and provides support for the nacelle, as well as access to it for proper maintenance. The most common design for the tower for whole-house systems is a white steel cylinder. It is usually around 150 to 200 feet in height, and has a diameter of about 10 feet. They have ladders which traverse the inside for hoisting equipment and tools.

That being said, there are smaller systems with pipe towers as narrow as 2 inches, that are supported by guy wires to maintain stability.

The base is dependent upon the type of tower you employ. For a whole-house system, it is created from concrete and has steel rebar reinforcement. This base supports the entire structure.

Two primary base designs are used. The first consists of a flat disk that is shallow and has a diameter of approximately 40 feet. The second has a diameter of about 15 feet, but is 16 feet deep, and cylindrical!

Smaller systems that use guy wires have a much smaller base holding the pipe, but require concrete anchor points for the wires.

yourhome.gov.au

yourhome.gov.au

The blades are designed on the same principle as airplane wings or propellers. Most of the modern type turbines utilize lift to harness the energy from wind. A pocket of pressure is created as wind passes behind the blades. This pulls the blade which results in the rotation of the turbine. The modern blueprint harnesses the wind’s energy with greater efficiency than that of older farmstead windmills.

turbine-blades

The nacelle contains a gearbox and a generator. A series of gears attaches the spinning blades to the generator. The rotational speed of the blades is increased by these gears and generate speeds of more than 1,500 RPMs.

Electricity is produced as the generator revolves. Some generators have a fixed speed, while others are variable. Variable speed generators must be corrected to 60 cycles per second systems. Fixed speed generators require no correction; however, they are unable to take advantage of wind speed fluctuations.

Most installers recommend an average wind speed of 12 mph or higher. It is also important that the turbine has access to relatively unobstructed winds. This sometimes requires larger land lots and higher towers.

The biggest reason that turbine use is not popular in urban areas is because of poor wind quality. The second reason is due to zoning restrictions.  These two are generally related:  The city or town won’t allow you to erect a tower high enough to get good wind flow!

However, if you live in an area where wind generators are an option, they are definitely worth considering.

 

Need more information?  Go to the Member link at the top of the page, click Independence Library, and download our complimentary copy of Small Wind Turbines At Your Home and Farm.

 

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