Selecting a Home Turbine
You open the door and a stern-looking constable is waving a piece of paper. “One of your neighbours has filed a complaint, sir. She says she can’t sleep at night because of the noise coming from your home turbine. You’ve picked the wrong location to live.”
If you’re about to buy a home turbine to save on your electricity bills, consider a few things before doing so; that is, if you don’t want people knocking at your door, accusing you of causing too much noise. Domestic home turbines are excellent energy savers, but you need to know some fundamentals! Knowing the basics can help you achieve significant savings on your electricity bill and enable you to spend more on home insurance premiums and other safety nets.
Wind Turbines: Size, Suitability and Location
Wind turbines generally come in three sizes:
large – these turbines produce hundreds of megawatts of electricity (expressed as “MW”) and are ideal for clusters of homes, farms or small businesses. Large turbines are usually installed in reserved places called windfarms.
small – these are ideal for homes, small farms or a small business. They produce no more than 100 kilowatts (KW) of electricity and can be used as a back-up power supply or to decrease energy consumption.
very small – these turbines are used to charge batteries of a large number of recreational vehicles like small boats.
As a homeowner, you would focus on the second type – the small home wind turbine. But home ownership is not the only deciding factor. As the constable said to the resident above, location also determines whether or not you can have one!
What makes a domestic wind turbine feasible?
your electricity bills are unusually high,
your house is located in an area that has sufficient amounts of wind energy,
the size of your property is at least one acre,
the borough you live in does not prohibit the installation of wind turbines,
the distance between you and your neighbours is at least 200-300 meters (this distance could vary, depending on local zoning laws),
the location of your property does not have access to major sources of electricity.
Location is a key factor. It has an impact on how efficient your home wind turbine will be. Make sure that you choose an area that does not obstruct the wind. Bad choices would be areas with tall buildings, massive industrial equipment, silos and a high concentration of houses. The ideal location therefore would be on a hilltop or on a shoreline and where there aren’t too many trees. Find a place where your turbine can “capture” as much wind as possible.
One more thing: don’t expect it to generate the same amount of energy every day. Wind speeds can vary within a 24-hour period. Bear this in mind when you notice that your home turbine is not supplying the same amount of energy consistently.
Wind Turbines: Types
Two types of wind turbines are available: horizontal axis and vertical axis. The horizontal axis type comes with a tower, the vertical ones are usually anchored to the ground.
The horizontal axis turbine is the most common and is installed so that it aims directly at the wind. It has a component called a tailvane that will point the turbine to the direction of the wind. The vertical axis type can be installed in whichever way the wind blows, but it needs more ground space to accommodate the wires and other components.
Each type has advantages and disadvantages. The merits of the horizontal axis turbine are that the blades are aligned to the turbine’s centre of gravity, thus making the turbine more stable; this also enables the blades to function better with wing warp for greater control and maximum wind energy capture. Another advantage lies in the tower. The height of the tower determines degree of access to wind shear. The taller the tower, the stronger the wind shear where wind speeds can increase by as much as 20%.
The disadvantages of horizontal axis turbines are logistics (the towers and blades are difficult to transport and install). Installing them requires heavy-duty equipment and operators. Tall towers are also frowned upon by military officers because they can obstruct air force facilities. Another disadvantage is that unusually strong turbulence could cause structural defects in the tower or in other components.
Going now to the vertical axis turbines, a few advantages include ease of maintenance, higher pitch angle for airfoil, enhanced power generation (if placed close to the ground), less risk of breaking and the capability of turning regardless of wind direction. Their disadvantages are that they produce energy at only 50% of what the horizontal axis turbines produce, the land on which they stand must be very flat, they have low starting torque, and they require guy wires that could cause stress on the bearings that hold the turbine together.