1. National Energy Situation

As the population of the world continues to grow and more developing countries are
moving towards an industrial economy, the consumption of petroleum based fuels is also
increasing. According to a recent release by the Energy Information Administration (EIA), it is
predicted that the cost for domestic electricity will increase by 1.8 percent annually in both 2009 and 2010. However, we have already seen increases of approximately 11% in consumer electrical rates for 2009.  Most of the electricity generated in North America is done so by burning fossil fuels (oil,
natural gas, and coal). The heat given off in the combustion process is used to make steam that can then be used to spin the turbine generators that produce electricity. Coal is by far the most common source of generated electricity, accounting for 46% of the total amount produced. In fact, approximately 90% of the coal mined in North America is used for the production of electricity. Though coal is a fairly abundant fossil fuel within our continent, there are a number of environmental issues pertaining to its use. Until the 1960s and 1970s, there were very few environmental restrictions in place for coal power plants to follow. However, due to the growing concerns surrounding acid rain (sulfur-dioxide) and the sizable emissions of carbon dioxide contributing to the greenhouse effect, the Federal Government intervened with the Clean Air Act and the Clear Water Act to help reduce the amount of pollution expelled into the environment. Since then, the energy industry has been continually researching new ways to reduce the
amount of harmful compounds produced by their power plants and other facilities. However, the
development and implementation of these solutions cost a great deal of money. Therefore, as the
demand for electricity continues to rise and tighter constraints are placed upon the emission of
coal-based generation facilities, the price of electricity will also increase.

2. History of Wind Power

Since ancient times, man has harnessed the power of the wind for a variety of tasks.
Some ancient civilizations, like the Persians (500-900A.D.), used the wind to grind grain into
flour, while others used the wind to transport armies and goods across the ocean and other bodies
of water. More recently, mankind has used the power of the wind to pump water and produce
electricity. The first man to harness the power of the wind to produce electricity was Charles F.
Brush. Brush was the owner of Brush Electric in Cleveland Ohio and in 1887 he created the
first automatically operating wind turbine. Brush’s turbine was very large compared to other
wind mills of the time period. His turbine stood about 75ft tall with a rotor diameter of 50ft and
consisting of 144 blades made from cedar wood. The output from Brush’s creation
was only about 12kW, but he ran the turbine for 20 years and used it to charge batteries in the
basement of his mansion. Poul la Cour is considered the pioneer of modern electricity generating wind turbines in Denmark because of his vast contributions to the basic principles that govern modern wind
turbines. Cour was originally trained to be a meteorologist and brought this background,
along with knowledge of modern aerodynamics, into the field of wind turbines. He built two
wind turbines at the Askov Folk High School in Askov, Denmark in 1897. Cour used the wind
turbines to generate electricity and produce hydrogen to be used for the school lights. He was the
founder of the Society of Wind Electricians in 1905 and published the first journal on wind
power; the Journal of Wind Electricity. The next leap forward in the wind power industry occurred in Denmark during World War II by a company called F.L. Smidth Turbines. Smidth Turbines began producing two and three bladed turbines that produced a DC voltage. In 1951, they replaced one of their DC turbines with a 35kW AC generator, making the wind turbine the second in the world to produce
AC. Johannes Juul will always be remembered as the man who pioneered the development of
the AC generating wind turbines. Juul’s background in wind power came from being one of
Poul la Cour’s “Wind Electricians.” Juul built a 200kW turbine for SEAS Power Company in
southern Denmark in 1956. His wind turbines were very advanced (at the time) and included
electromechanical yawing and aerodynamic tip brakes. His first wind turbine ran for 11 years
without any maintenance. During the next 4 decades, wind turbines were produced using the basics set forth by Brush, Cour, Smidth, and Juul. As the years went by, the turbines became more efficient, quieter,
safer, and more reliable due to technological improvements.

3. Wind Power Technology

The Power of Wind

There are many different types of air flow that can be observed. Some are useful to the
wind power industry; others are not useful at all. The winds that influences weather the most are
called Global winds or Geostrophic winds. Global winds are caused by the cyclic heating and
cooling of the earth and the associated pressure differences. Most of the heat on earth exists near
the equator. Air near the equator is warmer than the air at either pole. The difference in
temperature creates a difference in pressure and winds that move North and South from the
equator towards the poles are created daily. When this mass of warmer air tries to move north
and south, an interesting phenomenon occurs, called the Coriolis force. The Coriolis force is
caused by the rotation of the earth. The result of the rotation is a bending of the air mass towards
the right or left depending which hemisphere is observed. The Coriolis force stops the air jet
from going any further than 30 degrees latitude North and South. The Coriolis force is the cause
for the Prevailing Wind Direction. Another interesting fact about global winds is that they aren’t affected by the surface of the earth. Global winds are found about 3300ft above ground. The global winds are measured using weather balloons that record the data and transmit it back to earth.
Surface winds are the winds up to 330ft above ground. There a few different types of
surface winds, ranging from sea breezes to mountain winds. Sea breezes take place where the
ocean meets land. During the day, the land heats up much quicker than the ocean, causing a low
pressure area to occur over the land mass. The cooler air over the ocean rushes into the land
creating a breeze. During the evening and night, the opposite occurs but on a small scale because
the sea heats up and cools down much slower than land, so the winds are gradual. Mountain
Ranges have different types of surface winds. Valley winds are very common in mountainous
areas because large south facing slopes. During the day, the air rushed up the slope towards the
top of mountain and then during the evening and nighttime, the air rushes back down the slope
into the valley. Another mountain type wind is canyon winds which can race up and down
canyons or long slightly sloped valleys. All of the surface-type winds are useful in producing
electricity using wind turbines. Extracting energy from the wind is a precise science. The amount of energy transferred to a rotor of a wind turbine is a function of the wind speed, the air density, and the rotor area. The faster the air is moving, the faster the blades on the turbine will spin, increasing the energy produced. Heavier or denser air has more potential to extract power from the wind because
denser air can move the turbine blades more effectively. Lastly, to a certain point, the larger the
rotor area, the more wind that will be utilized by the turbine, thus more energy production. The
kinetic energy of a moving body is proportional to its mass. In terms of wind, the kinetic energy
in the wind depends on the density of the air or it’s mass per unit volume.
Measuring wind velocity and direction is one of the most critical preliminary steps to the
successful installation of a wind turbine. Wind is measured with a device called an anemometer.
If anemometers are to be fitted onto a mast, they should be fitted to the prevailing wind side, or
better yet, placed on top of the mast to minimize wind disturbance caused by the mast.
Before the specifics of turbine design are examined, let us consider the two general
categories of wind power technologies. These categories are Vertical-Axis Systems and
Horizontal-Axis Systems, each of which encompasses their own benefits and detriments
compared with the other. The Vertical-Axis turbine operates exactly as its name would suggest. In this
design, the axis of rotation is oriented vertically, perpendicular to the surface of the earth. One
of the major benefits of such a design is that it is able to operate at maximum efficiency no
matter which direction the wind is coming from. Horizontal-Axis turbines have an axis of rotation parallel to the ground, pointed either into the oncoming wind flow (upwind) or with the direction of the wind
(downwind). To take advantage of the increased wind speeds at higher altitudes above the
earth’s surface (as well as to provide clearance between the rotor blades and the ground),
horizontal-axis turbines are often mounted on top of a tall tower.  A major benefit of the horizontal systems over the vertical ones, often making them much more productive for any given location.
However, unlike vertical-axis systems that operate at maximum efficiency for any wind
direction, horizontal-axis turbines require an additional “steering” or yaw mechanism to keep the
turbine tracked directly into or with the wind. As the direction of the wind fluctuates even a few
degrees, a wind vane sensor and control system trims the yaw of turbine so that the rotor can
extract the maximum amount of energy from the wind. Such systems add complication and cost
to the overall turbine package, increasing both the initial and maintenance costs for the
horizontal turbines over the vertical ones.

4. Major Components of a Wind Turbine

 Generator
The generator is the component of the wind turbine responsible for converting the
mechanical motion of the rotor into electrical energy. There are many different types and sizes
of electric generators for a wide range of applications. Depending on the size of the rotor and the
amount of mechanical energy removed from the wind, a generator may be chosen to produce
either AC or DC voltage over a variety of power outputs. There are two main types of electrical generators for converting mechanical energy. The first is the Synchronous generator. The synchronous generator operates on the principle that as a magnet is rotated in the presence of a coil of wire, the changing magnetic field in space induces a current, and therefore a voltage in the coil of wire. In our case, the magnet is attached to the input shaft of the generator and is surrounded by several coils of wire, individually referred to as a pole. As the shaft rotates, so does the permanent magnet which creates a changing magnetic field in the presence of the poles which surround it. This induces a current in each of these poles and electrical energy is produced. Synchronous generators are typically quite simple and can be used in a wide variety of applications. The second type is the Asynchronous generator. At the heart of this design is its cage rotor, which is essentially a cylindrical cage of copper or aluminum bars that concentrically surround an iron core. Once again, this rotor is surrounded by a series of poles on its periphery called the stator. One way in which the asynchronous generator varies from the synchronous one is in that it is actually powered by the grid to set itself into motion initially. As the current
from the grid passes through the stator, a current is induced in the cage rotor itself; causing
opposing magnetic fields that set the rotor in motion at a specific rotational speed (this speed is
determined by the frequency of the supply current and the number of poles in the stator). The
generation of electricity occurs when the wind causes the rotational speed of the rotor to increase
above this idle speed caused by the grid. What is fascinating about this phenomenon is that very
large voltages can be produced for comparatively small increases in rotational speed
(considerable voltage for 10-15 rpm increase). With the rotor already in motion, there is little
torque applied to the rotor shaft, ultimately resulting in less wear on the transmission. However,
the Asynchronous generator is much more complex that the synchronous one and also requires
an initial source of power to operate. Asynchronous generators are more appropriate for
applications where there is a fairly constant wind speed that rarely drops below a certain value.
This way, the generator is consistently producing its maximum power since the rotor speed is
above the idle speed. Synchronous generators are more appropriate in applications where the
average wind speed may be appropriate; however there are times when the wind speed may dip
far below the average for a sizeable period of time. There are two major steps which characterize the generation process. The first is the actual conversion of the mechanical energy to electrical, for which we employ one of the generators mentioned previously. However, the raw output of these generators is highly irregular with voltages and frequencies that may vary tremendously and are referred to as being
“wild” in nature. Therefore, we need a second step where the output from these generators is
regulated to a fairly constant voltage and frequency before it may be utilized in any sort of an
electrical application. To accomplish this, there are power processing devices that take the
generated output and produce a specific voltage and frequency. For example, to produce power
that can be passed through the electrical grid here in the United States, we would require a
regulation device that would output a 120V RMS AC voltage at a frequency of 60Hz.

Tower
One of the most important pieces of the wind turbine assembly is the tower that it is
mounted upon. Mounting a wind turbine on the highest possible tower results in increased
power production due to the stronger winds present at higher altitudes. In addition, the effects of
the wind shear caused by the surrounding terrain is also much less at higher altitudes, providing
yet another reason to mount the turbine as high as possible. Of course, there are some limitations as to how tall of a tower is appropriate for a given application. One such consideration is the structural requirement necessary to support the turbine being considered, included how much the turbine weighs as well as what types of environmental forces (high winds, snow, rain) it will have to sustain over time. Zoning regulations may also play a role in dictating the maximum allowable height that the turbine
assembly may be elevated off the ground. There are many different types of towers available for a wide variety of turbine sizes. One of the primary categories is the Lattice Tower which is essentially a very
narrow, pyramid shaped structure that is strengthened with trusses. Towers of this variety may
be self-supporting or they can be further supported by guy wires. The other predominant type of tower is the monopole tower.  This type of tower consists of a single pole that supports the turbine. As we might expect, lattice towers are much sturdier and can therefore elevate wind turbines to much greater heights than the monopole tower. However, the lattice towers also require more ground space for their larger footprint than what is necessary for a monopole tower.

5. How do Wind Turbines Work?
Wind turbines convert the kinetic energy of the fluid flow of the air (wind) into electrical
energy. The turbine apparatus has two roles; (1) To extract the energy available in the wind’s
motion via mechanical means using a rotor, and (2) To convert this mechanical energy into
electric energy that can be in turn converted into other forms of energy. While the specific designs and pertinent components of a given turbine are likely to be quite different depending on the application, the key mechanisms in accomplishing the functional goals of the turbine are rather consistent. These mechanisms are the rotor and the generator, each of which is responsible for the conversion of energy from one form to another. To gather the energy present in the wind, a rotor is used to translate the lateral motion of the moving air into rotational motion. The design of the rotor may vary a great deal from one
application to the next, depending largely on the aerodynamic principles employed in its design,
as well as upon the overall design of the wind system (Horizontal Axis versus Vertical Axis).
 
Operating Characteristics
While each turbine comes with its own myriad of operating specifications, there are a few
that are of particular importance when considering the right turbine for a given application. The
Cut-in, rated and Cut-out wind speeds of a particular turbine are of immense importance in
determining which model is best suited for a specific location. The Cut-in speed of a turbine is the minimum wind speed at which the rotor will turn fast enough to generate usable power. Due to the moment of inertia of the rotor, as well as the static forces within the turbine assembly, the wind must attain a nominal speed, the cut-in speed, to overcome these forces and set the turbine in motion. Once in motion, the rotor is supplying mechanical energy to the generator and the turbine can begin to generate power. The value of the cut-in wind speed is typically somewhere between 4-10 mph (2-4.5 m/s) for most wind turbines. In most applications, the lower the value of the cut-in speed the better, since the turbine will able to generate some sort of power even at the very lowest average wind speeds.
The Rated speed of the turbine is the minimum wind speed at which the generator will be
able to produce its rated power. At wind speeds above this rated value, the output of the turbine
levels off since the generator has already attained its rated output capability. Values for this
characteristic typically range from 25-35 mph (11.2-15.5 m/s). Average wind speeds within this
range would be ideal for generating maximum amounts of energy from a location. However, we
often find that the average wind speed is much less than the lower bound of a turbines rated wind
speed, sometimes by as much as 10-15 mph. The Cut-out speed of a given turbine is the wind speed at which the turbine mechanism will shut-down. When the wind speed exceeds this cut-out value, the turbine will begin to employ a series of protective measures to thwart the turbine from destroying itself. One such
measure is a very simple mechanical break within the turbine assembly that attempts to slow the
rotational speed of the rotor shaft via frictional forces. Other measures focus on the rotor blades
to slow the system down. One such measure employs individual pitch control of each blade to
decrease lift and slow the rotor, while another system, called the tip-break, makes a radical
change to the orientation of the tips of the blades, causing a great deal of drag which also serves
to slow the rotational speed of the turbine. Without these safety measures, the presence of a very
strong wind could cause the destruction of the turbine and put nearby residents and property in
great danger should the blades be ejected from the rotor, the tower fall over, etc. However, with
these systems in place, the turbine is able to survive these high winds and maintain the safety of
those nearby. The rotational motion of the rotor is transferred along a shaft that ultimately reaches a
generator. The specific method with which the generator produces electricity varies from system
to system, however the basic idea is that the generator transforms the mechanical motion of the
rotor into electrical energy, thereby fulfilling the functional duty of the wind turbine.

6. The life of a Turbine

Maintenance and System Life
To keep the wind turbines operating at the peak of their potential, manufacturers strongly
suggest that the entire system be completely checked on an annual basis. Not only does this
check include the mechanical parts of the turbine assembly itself, but it also includes the tower
and other support structures, as well as the wiring between the output of the turbine and
wherever the power is being routed. Some of the specific tasks within these and other areas
include greasing bearings, changing bearing packs as needed, checking rotor blades and braking systems, testing the wiring and connections, etc. Annual diagnostics such as these not only keep the system generating its maximum amount of potential power year after year, but they also keep the system from becoming a potential hazard to those working on and around it. By taking care of the equipment and performing these annual inspections, most manufactures predict a 20-30 year lifetime for their turbines.

Health and Safety Issues
When it comes to health and safety issues, the cardinal rule of wind power is to keep the
area within one hub height plus one rotor distance clear of any critical structures or people. This
is primarily due to the fact that if the turbine were ever to collapse, there would be nothing for it
to damage. One of the major safety concerns for wind turbines is the possibility of them throwing a
blade that has become damaged and separated from the hub. This was a major concern when
wind power was in its infancy, however with today’s technology, this is no longer a real worry.
Previously, the heavy metallic blades used in wind mills were susceptible to environmental
issues and fatigue. Though it was rare for them to actually separate from the hub, they could
cause a great deal of damage in the event that they actually did. The long metal blade could
travel quite a distance, but more importantly the absence of one of the blades would cause an
imbalance on the tower, resulting in tower collapse due to severe vibrations.
The newer blades used today are made of composites and plastics. These do not have
nearly the same weight as their metallic predecessors and are also less susceptible to
environmental factors. In the extremely unlikely event that the blades would be ejected, they
would not travel anywhere near as far as a metal blade. One of the major causes of blades being thrown is a blade rpm that is too high. With advances in windmill technology, this is much less of a concern. As we saw in our discussion of the cut-out speed for a given turbine, there are a number of safety mechanisms to slow the rotational speed of the rotor in the event that it should get too large.
Another potential problem for consideration is dealing with winter weather. While there might be more wind in the winter, the harsh weather can create layers of ice on the turbine blades. This ice can be thrown by the turbine as the blade flexes. This is of particular concern if the turbine slows or stops during a storm and then starts later on. The layer of ice that is formed will now be thrown as the blades flex under movement. In regards to electrical safety of small scale wind turbines, technology once again
helps prevent disaster. Today’s modern turbines incorporate a power controller which monitors
the turbine power production, the site’s instantaneous electrical needs, and grid power
availability. In the situation where grid power might be lost, the power controller will sense the
outage and will not try to “force” power into the grid. It does this by directing power solely to
the site. If the windmill is producing more power than the site is requiring, the turbines dump
load capability will prevent damage to the site. If this is still not enough, the turbine will
automatically slow or shut down entirely to prevent damage to electrical circuits.

Environmental Impacts
When anything foreign is introduced into the environment, one must consider the effects
of such a change or disturbance to the ecosystem. One of the primary concerns is the impact of
wind turbines on the local bird populations. It has been theorized that birds will fly into and
through the wind turbines unknowingly, resulting in the reduction of local bird populations.
This concern arose from a large wind farm at the Altamont Pass in California. The wind farm is
constructed of five thousand four hundred turbines closely packed and situated on a major raptor
migration corridor, which is also the location of the highest concentration of gold eagles in North
America. While there is some evidence to support the bird interaction theory with regards to
large wind farms composed of multiple turbines, there is no evidence that a single turbine will
have a severe impact. In fact, the impact has been stated to be less than one in thirty thousand
(roughly one to two birds per turbine, per year) when compared to other man-made structures
such as buildings, traffic, and even house cats. Wind turbine impact on bat populations has
not been studied as extensively, but it is theorized that the impact is even lower than that for
birds. Conventional fuels used in other forms of electricity-production have a far greater
environmental impact due to their pollution of air and water sources.
Wind turbines are tall structures that must rise above all the surrounding buildings and
trees. Thus they are quite visible and change the look of the sky line. If situated in a rural area,
residents might be unwilling to see the beautiful landscape marred with a turbine. While not
everyone will see a turbine as a blemish, it must be considered that some might. In some
communities with cell phone towers, the residents have pushed for the cell companies to disguise
the tower as a tree, thus lessening the visual effects on the environment. As of now, wind towers
do not have the same camouflaging technology. In addition to impacting the ecological environment, wind turbines also have an impact on the social environment of the human population. One of the first things people are concerned about is the acoustic noise that the windmills generate. Many do not realize that today’s turbines are very quiet. When standing a couple hundred feet away, the noise level is comparable to that of a running refrigerator. Bergey Windpower, Co. has performed studies on their 10kw model where at distance of forty two feet from the base of the tower, the sound level was only three to four decibels above the ambient noise of its surroundings. When operated unloaded at high wind
speeds, the turbine was actually around fifteen decibels higher than ambient noise, but the advent
of dump load circuits allows one to never run the wind mill unloaded.
There has also been great concern over the “ghosting” of television screens in homes near
the wind mill caused by interference from the rotor blades. While this was a legitimate concern
when metal blades were used, today’s composite blades do not produce the same electromagnetic
interference. Therefore, ghosting of television screens is no longer a major concern.

7.Site Assessment
In order to properly asses the feasibility of a wind turbine on any given property, a
wind study that provides real, on site measurements of actual wind speeds is recommended and we consider it necessary. While area wind maps and local geographic information are available,
in a situation that requires such a large monetary investment, more accurate data should be obtained. Ideally a tower, with a weather station, comparable in height to the proposed
wind turbine would be constructed at the prospective wind turbine location to provide an exact
measurement of wind speeds to be experienced by the turbine. Due to the variation of wind speeds and temperature ranges, it is often suggested that data should be collected for a minimum of one full year. Our design intent is to gather accurate, site specific data that could be used to reinforce the economic feasibility of a wind turbine at your property.  We do so as quickly as possible, sometimes correlating the data received with that as published in as little as 3 months.

Published Wind Data
Wind speeds are normally only measured when there is a specific need, such as an airport
or a weather collection point for news stations. Some private citizens monitor wind speeds for
their own recreation, but it is usually done at a low elevation and is therefore not suitable for use
with a wind turbine study. In recent years, there has been a strong push to determine average
wind speeds for all areas of the nation. While many measurements are taken to provide data for
the wind speed maps, obtaining measurements for every point in the nation is obviously not
feasible. Due to the difficulty in getting these accurate measurements, the maps rely heavily on
terrain modeling and algorithms to determine the most likely average wind speed, at all different
elevations, based off of nearby actual measurements. These wind maps for Michigan are
available to the general public via the world wide web.

Land Area
A critical role in the erection of a wind turbine is that of the land area where the turbine
will be placed. Without a suitable location to place a turbine, large wind resources and favorable
zoning are essentially useless. When searching for a feasible area, many different factors play
into the overall equation. One must analyze the surrounding boundaries, utility line locations,
elevations, obstacles, easements, ground composition and not only current buildings, but also
proposed for the future. When constructing a wind turbine or farm in remote locations  many of these factors become less important. When the proposed turbine is to be put in a densely populated area, the issue ofsurrounding land area is absolutely critical to the success of the project.

Boundaries
The first piece of the puzzle to be analyzed is the surrounding property boundaries. The
tower must be situated in such a place that in the remote chance that the tower was to fall, it
would not fall onto another landowner’s property.
Next, existing distribution line locations must be analyzed. The turbine must be placed in
such a manner that in the remote chance of a fall, it would not land on any existing energized
electrical conductors.
Due to the small amount of noise generated by the turbine, it is advisable to situate the
turbine roughly 2 times the total height, from any nearby dwellings as space permits. This should be sufficient since noise studies have concluded that, at a distance of 100 yards, wind turbines are no louder than a regular household refrigerator.
Due to the fact that wind speed increases with elevation, the most favorable site for the
turbine is at the spot of highest elevation. Situating the turbine at a higher elevation also
decreases the interference that other surrounding structures and vegetation might have on wind
speeds.
Grid interconnection must also be considered when planning where to install the turbine.
When choosing between available sites, the site closet to the point of interconnection should be
chosen to reduce installation costs associated with running wires from the turbine to the point of
interconnection.

Electricity Usage
A typical one family home uses about 10-20 kWh a day, or about 4,000 – 7,000 kWh a year.

8. Economics
Turbine Selection
Turbine selection is one of the most important considerations in a wind turbine project.
There are many types and sizes of wind turbines available in the world today. In order to choose
a wind turbine to fit a particular situation, information is needed about the site. The most
important information needed is the average yearly wind speeds at different heights and the load
profile of the building or home that will be using the generated electricity. The yearly average wind speeds will be used to calculate the expected generation of a wind turbine so that they can be correlated with the load profile. The ideal case would be an expected generation profile that
exactly matches the load profile. This would mean that the building would use all the electricity
generated by the wind turbine. The closer the load profile gets to the expected generation profile,
the better the economics will work out. An important consideration is the capacity factor. The capacity factor is basically the used percentage of the wind turbine. If the turbine were to operate at 100% capacity, then the turbine would be outputting its rated output all the time. If the turbine was to operate at 50% capacity, it would be outputting 50% of its rated output all the time, or conversely, it would
output its full output 50% of the time. The higher the capacity factor, the more economical the
turbine will be.

Expected Generation Profile
After deciding on a wind turbine model to use, a more in depth analysis needs to be
performed to figure out exactly how much electricity the wind turbine will be expected to
generate. Other questions to be investigated are how well the generation profile fits with the load
profile. In order to figure out how much electricity is expected to be generated, you have to use
the data from the turbine power curve. The data is utilized so that the percentage of time producing power, along with the power output of the turbine at the expected wind speed, and should then be converted to a kilo-watt-hour measurement. It is then easy to multiply by twenty-four hours in a day and then by the number of days in a month to get the expected monthly output.
It should be noted that there is a higher percentage of faster wind speeds during the
winter months than during any other season. Using these assumptions and data, the expected
output of the wind turbine per month can be estimated.

Net Metering
Net metering is an extremely important incentive in making wind power and other
renewable technologies financially feasible. For any renewable technology that depends on the
environment, the power output profiles of these systems are largely unpredictable. For example,
the amount of wind present at a particular location for any given instance of time is dependent on
a variety of factors, including temperature, barometric pressure, humidity, etc. As a result, there
will be days when the wind speed is extremely high, and others when there will be no wind at all.
What is most unfortunate is that a generating facility may produce more power than they need on
the windy days, while on calm days, they will be forced to buy electricity from the utility. If
there were a way for a facility to store the energy generated during windy periods of peak
production for use during times of less favorable wind conditions, such an arrangement would
enable a facility to maximize the consumption of the energy they produce before needing to rely
on a utility. Net metering is a means of accomplishing this without requiring any physical device for
energy storage such as a battery. The conceptual benefit of net metering is the fact that when
more energy is being generated than used, the meter that has been tracking the amount of energy
that has been consumed from the utility will run backwards, effectively “paying” for the
electricity consumed during periods of low production. The most important part of net metering is that the production facility is essentially “selling” their energy at its retail value. In most situations, excess energy is bought by the utility at cost, meaning the price that the utility would pay for electricity before adding their transmission and distribution charges. The difference between the cost and retail values of the
electricity can be quite substantial, varying from $0.05-0.06 /kWh depending on the contract
with the utility. Therefore, by offsetting their energy consumption at the retail price via net
metering, a facility will be receiving $0.05-0.06/kWh more for the energy they produce.
More than 35 states currently employ net metering programs as an incentive for
renewable technology, each with a list of conditions and laws specific to their particular agenda
regarding energy. Michigan currently has a more favorable net metering program which employs the concept of “true” net metering.  In essence, the consumer is paid the same rate that they would pay to the utility, almost.  With the exclusion of certain governmental regulatory charges, the consumer should be able to receive the full rate.  We encourage you to review the Michigan Public Service Commissions web site regarding net metering for more information.

Tax Incentives
There are a variety of tax incentives at both the state and federal level to help promote the creation of renewable energy sources. These incentives include property, income and sales tax exemptions for individuals and organizations across several sectors, including Commercial, Industrial, Municipal and Residential. A complete list of the State and Federal tax incentives available can be found at the Database of State Incentives for Renewable Energy (DSIRE) website: http://www.dsireusa.org/.  Currently there is a 30% federal tax credit on the purchase price and installation cost of a wind energy system.  We encourage you to review the link on our page for more information.