Unlike yesteryear's windmill, today's wind turbines use
technological innovations that have substantially reduced the cost
of electricity generated from wind power. In the 1920s and '30s,
farm families throughout the Midwest used wind to generate enough
electricity to power their lights and electric motors. The use of
wind power declined with the government subsidized construction of
utility lines and fossil fuel power plants. However, the energy
crisis in the 1970s and a growing concern for the environment have
generated an interest in alternative, environmentally friendly
energy resources. Today, homeowners in rural and remote locations
across the nation are again examining wind power to provide
electricity for their domestic needs.
Benefits
of Wind Power
A wind energy
system can provide a cushion against electric power price increases.
Wind energy systems help reduce U.S. dependence on fossil fuels; and
they are nonpolluting. If you live in a remote location, a small
wind energy system could help you avoid the high costs of having
utility power lines extended to your site.
Although wind
energy systems involve a significant initial investment, they can be
competitive with conventional energy sources when you account for a
lifetime of reduced or altogether avoided utility costs. The length
of the payback period - the time before the savings resulting from
your system equal the cost of the system itself - depends on the
system you choose, the wind resource on your site, electricity costs
in your area, and how you use your wind system.
Is Wind
Power Practical for You?
Small wind energy systems can be used in connection with an
electricity transmission and distribution system (called
grid-connected systems), or in stand-alone applications that are not
connected to the utility grid. A grid-connected wind turbine can
reduce consumption of utility-supplied electricity for lighting,
appliances, and electric heat. If the turbine cannot deliver the
amount of energy you need, the utility makes up the difference. When
the wind system produces more electricity than the household
requires, the excess can be be returned to the grid. With the
interconnections available today, switching takes place
automatically. Stand-alone wind energy systems can be appropriate
for homes, farms, or even entire communities (a co-housing project,
for example) that are far from the nearest utility lines. Either
type of system can be practical if the following conditions
exist.
Conditions for Stand-Alone
Systems
-
You live in an area with average annual wind speeds of at
least 9 miles per hour (4.0 meters per second).
-
A grid connection is not available or can only be made
through an expensive extension.
-
The cost of running a power line to a remote site to
connect with the utility grid can be prohibitive, ranging from
$15,000 to more than $50,000 per mile, depending on
terrain.
-
You have an interest in gaining energy independence from
the utility.
-
You would like to reduce the environmental impact of
electricity production.
-
-
You live in an area with average annual wind speeds of at
least 10 miles per hour (4.5 meters per second).
-
Utility-supplied electricity is expensive in your area
(about 10 to 15 cents per kilowatt hour).
-
The utility's requirements for connecting your system to
its grid are not prohibitively expensive.
-
Local building codes or covenants allow you to legally
erect a wind turbine on your property.
-
You are comfortable with long-term
investments.
-
Net metering is available
Is Your Site Right?
The U.S. Department of Energy (DOE) has compiled wind
resource maps that are available from the American Wind Energy Association and Wind Powering America.
DOE maps are good sources for regional information and can show
whether wind speeds in your area are generally strong enough to
justify investing in a wind system.
Wind-turbine
manufacturers can use computer models to predict machine performance
at a specific location. They can also help size a system based on
your electricity needs and the specific local wind patterns.
However, you will need site-specific data to determine the wind
resource of your exact location. If you do not have on-site data and
want to obtain a clearer, more predictable picture of your wind
resource, you may wish to measure wind speeds at your site for a
year. You can do this with a recording anemometer, which generally
costs $500 to $1,500. The most accurate readings are taken at "hub
height" (i.e., the elevation at the top of the tower where you will
install the wind turbine). This requires placing the anemometer high
enough to avoid turbulence created by trees, buildings, and other
obstructions. The standard wind sensor height used to obtain data
for the Department of Energy maps is 33 feet (10
meters).
Maps available in the table at right give general
information on the average wind resources available across the
country and in Montana. Of course, the actual wind resource on your
site will vary depending on such factors as typography and structure
interference.
You can have varied wind resources within the
same property. If you live in complex terrain, take care in
selecting the installation site. If you site your wind turbine on
the top or on the windy side of a hill, for example, you will have
more access to prevailing winds than in a gully or on the leeward
(sheltered) side of a hill on the same property. Consider existing
obstacles and plan for future obstructions, including trees and
buildings, which could block the wind. Also realize that the power
available in the wind increases proportionally to its speed
(velocity) cubed (V3). This means that the amount of power you get
from your generator goes up exponentially as the wind speed
increases. For example, if your site has an annual average wind
speed of about 12.6 miles per hour (5.6 meters per second), it has
twice the energy available as a site with a 10 mile per hour (4.5
meter per second) average.
Additional
Considerations
In addition to the factors listed
previously, you should also:
-
research potential legal and environmental
obstacles;
-
obtain cost and performance information from
manufacturers;
-
perform a complete economic analysis that accounts for a
multitude of factors;
-
understand the basics of a small wind system,
and
-
review possibilities for combining your system with other
energy sources, backups, and energy efficiency
improvements.
You should establish an energy budget to help define the size
of turbine you will need. Since energy efficiency is usually less
expensive than energy production, making your house more energy
efficient first will likely result In being able to spend less money
since you may need a smaller wind turbine to meet your
needs.
Before you invest any time and money, research
potential legal and environmental obstacles to installing a wind
system. Some jurisdictions restrict the height of the structures
permitted in residentially zoned areas, although it's often possible
to obtain a variance. Your neighbors might object to a wind machine
that blocks their view, or they might be concerned about noise.
Consider obstacles that might block the wind in the future (large
planned developments or saplings, for example). If you plan to
connect the wind generator to your local utility company's grid,
find out its requirements for interconnections and buying
electricity from small independent power producers.
Pricing a System
When you are confident that you can install a wind machine
legally and without alienating your neighbors, you can begin pricing
systems and components.
Approach buying a wind system as you
would any major purchase. Obtain and review the product
literature from several manufacturers. Once you have narrowed the field, research
a few companies to be sure they are
recognized wind energy businesses and that parts and service
will be available when you need them. Also, find out
how long the warranty lasts and what it
includes.
Ask for references
of customers with installations similar to the one you are
considering. Ask system owners about performance, reliability, and
maintenance and repair requirements, and whether the system is
meeting their expectations.
A residential wind energy system
can be a good long-term investment. However, because circumstances
such as electricity rates and interest rates vary, you need to
decide whether purchasing a wind system is a smart financial move.
Be sure you or your financial adviser conduct a thorough analysis
before you buy a wind energy system.
