frequently asked questions about Wind Energy
Q: How do I tell if I have enough wind to use a small wind turbine?
A: The best place to start is with a regional wind map. This
can show you typical annual wind speeds for your area. You will need a
minimum average wind speed of 10 miles per hour for a small turbine to
be viable. See our Wind
Maps section for more on this. You can also use a device called
an anemometer to measure wind speed. But keep in mind that the
wind speed at ground level will be much slower then wind speed at the
top of the tower where your turbine will be.
Q. What do I do on days when the wind isn't blowing?
A: If you have a grid-connected system then you don't need
to worry about it. You would simply use the energy off of the
electrical grid until the wind starts blowing again. If you are
off of the grid then you have several options. The most common
approach is to use a battery bank to store the energy the wind turbine
is creating. You could also use a backup generator. Yet another option is to use a hybrid system using
solar panels. One of the great things about this type of
approach is that on the days when the wind is not blowing it is
usually sunny. The two approaches to generating energy
compliment each other.
Q: Are wind turbines noisy?
A: Despite what many people believe wind turbines are not
particularly noisy. Modern residential wind turbine designs have
eliminated most of the noise by going to direct drive generators which
have few moving parts. Most of the sound is aerodynamic noise caused
by the blades passing through the air. While this will generate some
noise it is usually not much more than the noise generated by the wind
Q: How big a wind turbine will I need to power my home?
A: This depends upon a number of factors, the most critical being the amount of energy you normally consume. If you use around 800 kilowatt hours per month then you would need a wind turbine in the range of 5-15 kilowatts assuming you have acceptable wind speed.
Q: What happens if we get a really high wind? Could it break
the wind turbine?
A: Modern wind turbines have special features which are designed
to handle excessively high winds. Wind turbines have a
wind cut-out speed. If this speed is exceeded the turbine will
take action to prevent damage to the turbine. There are a number of
approaches to doing this. In some machines an automatic brake is
activated by a wind speed sensor. Some machines twist or "pitch" the
blades to spill the wind. Still others use "spoilers," drag flaps
mounted on the blades or the hub which are automatically activated by
high rotor rpm's, or mechanically activated by a spring loaded device
which turns the machine sideways to the wind stream. Normal wind
turbine operation usually resumes when the wind drops back to a safe
Q: How Do Small Wind Systems Affect Property Values?
Most research on this subject has tended to show that residential wind
turbines tend to increase, not decrease property values. They
also do not appear to diminish property values for nearby residents. A
2002 survey of 300 California homeowners, conducted for the California
Energy Commission by a market research firm, found that 50% of
homeowners surveyed "would be willing to pay more for a home equipped
with solar and wind technology."
Q: How long will it take for the wind turbine to pay for itself in energy
The time to recoup the investment depends upon a number of factor including the
cost of electricity in your area, the local wind speed, turbine size, and the
nature of state and federal incentives. Most current wind turbine users
have been able to recoup their investment in 6 to 15 years. Wind turbines
require minimal maintenance and will last anywhere from 20 to 30 years.
Q: Do Small Wind Systems Kill Birds?
A: Birds can collide with any number of man-made structures including
wind turbines. However, keep in mind that for every wind turbine out there
you will find thousands of telephone poles which have about the same level of
risk. Most bird collisions are from moving vehicles. Reports of
residential-scale wind turbines killing birds are very rare.
Q: How much space will I need in order to have a wind tower?
A: Very small wind turbines can be placed close to your home but
will not generate a great deal of electricity. If you are going to put
up a tower you will probably want to have at least an acre of land for
Q: Could I mount the wind turbine on my roof instead of having to
put up a tower?
A: As a general rule wind turbines should not be mounted on
homes because the vibration from the turbine could be transferred to
the building and damage both the mounting and the building. In addition
most turbines need to be mounted higher than the typical roof in order
to get good wind speed and avoid turbulence.
Q: How much electricity can one wind turbine generate?
A: Wind turbines being manufactured now have power ratings
ranging from 250 watts to 5 megawatts (MW). Example: A 10-kW wind
turbine can generate about 10,000 kilowatt hours annually at a site with wind speeds averaging 12 miles
per hour, or about enough to power a typical household.
Q: How much does a wind system cost?
A: A small turbine can cost anywhere from $6,000 to $22,000
installed, depending upon its size, features and service agreements.
However, most states provide tax breaks and other incentives which can
help to reduce the cost.
Q: Will I have to perform much maintenance?
A: Most small turbines have very few moving parts and do not
usually require significant maintenance. They are designed for a long life (up to 20 years) and operate completely automatically.
It is a good idea to inspect your wind turbine once per year to look
for any damage from wind born particles or excessive wear.
Rather than climb a tower you may want to arrange to have your
supplier do this as part of your service agreement.