site requirements for Wind Energy Systems
The first question that should always be asked when choosing a site
is "Does it have enough wind?". Fortunately this is a question
that is fairly easy to answer. Wind maps which show both annual
and seasonal wind speeds are available from a variety of sources
including the U.S. Department of Energy (DOE), the National Renewable
Energy Laboratory (NREL), the American Wind Energy Association and Wind Powering America.
These maps can help you determine if wind speeds in your area are strong enough to justify investing in a wind system.
To get more information on maps for your locale click on Wind Maps
in our menu.
If you are hesitant to rely just on generic government data or if
data in your location is somewhat limited, another approach is to
actually take wind readings at your site yourself using a recording anemometer.
Anemometers are small and simple devices. A
number of the newer units are digital hand held recorders which allow
you to easily check wind conditions in different parts of your
property. The anemometers aren't hard to set up and many can record not only wind speed
but temperature and humidity as well. If your schedule allows you
may wish to take recordings at different times of the year in order to
get a complete picture of how the wind changes at your location by
season. Most portable digital anemometers cost between $200 to $500
and are available over the Web.
Another major consideration when selecting a site is the proximity
of the wind tower to your home or business. In most cases you
don't want the wind tower attached to the building itself because of
both noise and structural vibration considerations. However, if
the tower is too far away then you could incur significant costs in
running a power line from the tower to your house where the electric
meter is or, if you are off the grid, to where your batteries are
stored. That tower on the hill may sound nice but if the hill is
two miles away you might find that it will cost you more to run the
line then to have put up the tower in the first place.
Terrain is another consideration. If you live in a hilly area
it is good to take advantage of hills in order to gain additional
height for your tower. In particular, take care to avoid
locations where you are on the leeward (sheltered) side of a hill
since it would cut off the wind. Don't just consider existing obstacles.
If you are putting up the tower prior to building a residence,
consider the impact the home itself will have on wind patterns. Also
take into consideration any locations where you may be planning to put
up trees which could block the wind.
Never underestimate the impact even a small reduction in wind
velocity will have on your ability to generate power. Wind power increases
exponentially relative to speed (V3). A site with an annual average wind speed of about 12.6 miles per hour (5.6 meters per second), has twice the energy available as a site with a 10 mile per hour (4.5 meter per second) average.
Even if you have what appears to be a perfect site for wind power,
you should always check state and local regulations before investing
money in a wind energy solution. Take the time to research local
zoning requirements. Many communities have put up strong
restrictions on the height of structures. Wind turbines perform
better the higher they are placed but you may find that a 75 or 100
foot tower may violate local zoning requirements. For more information
on the impact of regulations check out the Government Regulations
section on our menu.
Also be considerate of your neighbors, particularly if they live
close to where you are thinking of placing your wind tower.
People can get awfully fussy about having their views block and what
might seem like a trivial view issue to you may be a very big issue
for them. Talk to your neighbors before proceeding, and if there
is a local community group for your housing area make sure you get
their input as well. Your neighbors might object to a wind machine that blocks their view, or they might be concerned about noise.