How Well Could Wind Power Work For You?

Please review the following consideriations prior to contacting us about residential wind power.

• How Much Power are you Using?
• Reduce Consumption
• What kind of average windspeed can you expect at your site?
• How big should the wind turbine be?
• Estimated Costs
• Detailed Windpower Potential Assessment
• Towers

How Much Power are you Using?
If you are connected to the grid, have a look on your power bill and you will be able to see how many kWh your home uses each month and should be able to determine your yearly consumption.  Once you have that figure, you can begin to research a wind turbine that could supplement the electricity you are usingfrom the grid. In some cases, you may even be able to cover your electrical bill with a small residential wind turbine but only if you have quite low usage (below 400KWh/month). 
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Reduce Consumption
We encourage everyone to look at ways to reduce electrical consumption before investing in a renewable energy system.  Go through your house and try to identify which appliances are using the most power and see if you can upgrade to something more energy efficient or just make sure anything that draws electricity is turned off when not in use ( a power bar is great for this).  A good place to start is to gradually change all of your lightbulbs to compact fluorescent as your old incandescent bulbs burn out.  You might also try to reduce overall usage by using a clothesline instead of the dryer. Once you have found ways to make your home as energy efficient as possible, you are ready to take the next step.
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What kind of average windspeed can you expect at your site?
In order to make good use of a wind turbine; you must have a good site.  A yearly average of 12mph (5.4 m/s) would be a good wind resource.  The only way to know what the average windspeed is at your site is to measure with a totalizing anemometer. It would be installed on a tower as high as you would eventually expect the wind turbine to be placed.  This is an investment but again, the only way to really know.  Another way to get a fair sense of your available wind resource is to consult wind maps.  Links to wind maps can be found at www.windenergy.com . You could also install a small turbine like the Air X and monitor it's output over the course of a year to get an estimate of the available wind resource.
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How big should the wind turbine be?
Many turbines are rated at their maximum output potential. For example the Whisper 500 is rated at 3 kW.  What this really means, is that the turbine will produce 3KW  but only when the wind is blowing at 24mph (10.5 m/s) It does not mean it will produce this amount of power very often.  If your average windspeed is 10mph, you would realistically get about 325 kWh a month out of the Whisper 500.  In other words, you would not find your turbine producing 3 KW continuously.
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Estimated Costs
Another important factor is cost.  Prices are set for the turbine itself and then another price for the tower, (depending on the height your site will require) There is yet more cost is added with the actual installation of the turbine.  It is impossible to give an accurate quote without visiting the site. There are many variables involved in designing a system such as the lay of the land, treeline height, amount of cleared land, accessibility, zoning by-laws and so on.  The average residential wind system (with turbines 3KW or less) will cost between $ 15,000.00 to  $ 20,000.00 or more.  There are incentives and tax rebates available in most states. Have a look at www.dsireusa.org to research what your state offers.
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Detailed Windpower Potential Assessment
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1. Choose The Best Site
   Select a site for your wind turbine where the wind is likely to be the strongest and least turbulent. Turbulence is caused by obstructions to the wind, such as nearby trees or buildings. Rooftop mounting of wind turbines is generally not recommended, because of vibrations and resonance’s that can be transmitted from the turbine to the building structure.
   
   
   A cleared hilltop exposed to the prevailing winds is an ideal site for a wind turbine. Generally, the higher the wind turbine is mounted, the stronger the available winds. "Flagging" of trees or vegetation is often an indicator of a good wind site. If you have no choice but to use a wooded site, then the tower should be at least twenty feet higher than the trees. If the ideal site is a long way from your house, the wind-generated power can be transmitted over greater distances by using a high voltage transmission line.
2. Check With Your Municipal and Regional Authorities
   Most towns have bylaws and regulations governing the erection of towers. Generally, local regulations require only that the tower not be hazardous or objectionable to your neighbors. Sometimes towers over a certain height require zoning adjustments, and only very occasionally are subject to civil aviation height restrictions.
   Noise is sometimes offered as an objection against wind turbines. This is a somewhat spurious objection, because unless you are standing very close to, or right underneath, the tower, the noise made by a modern residential wind turbine is usually no greater than the noise of the wind itself. Smaller turbines such as the Air X do make quite a bit of noise when the wind is really blowing but the wider (and slower) the swept area of the blades, the less noise is produced from flutter in high winds. Similar objections are sometimes made about bird collisions - birds are more likely to hit large stationary surfaces like buildings than they are to run into a narrow, rotating airfoil.
3. Measure The Average Wind Speed At Your Site
   The only way to find out exactly how much wind-generated electricity can be obtained from your particular site is by measuring the average wind speed. This is done by installing a "totalizing anemometer" at the exact spot where the proposed wind turbine will be located. By reading the totalizer from time to time, you will create a chart of average wind speed over time. An entire year's readings will show all the seasonal variations in your average wind speed, but you can also extrapolate just a few weeks' readings into a year by overlaying a pattern of the year's local seasonal variations, obtained from the nearest meteorological station or airport, over your chart. (The vertical scale of the charts must be the same). It is important to know the seasonal variations if you are designing an independent power system, in order to match the incoming energy to your load, year-round, and to have sufficient power available at the lowest-wind times of year (summer).
   
   Once you know the annual average wind speed at your site, then from the manufacturers' published specifications, which use standardized distribution of wind speeds for their averages, you can find out approximately how much energy, in kilowatt-hours per month, will be delivered by any type or make of wind turbine, of any size, at your particular site. The height of the anemometer and the height of the wind turbine tower are also taken into consideration in the energy calculation. Totalizing anemometers are available from NRG Systems see www.nrgsystems.com The “Windwatcher” is a popular product that will allow you to do your own site energy assessment. If you later install a wind turbine, the anemometer itself can be used as a system wind speed monitor.
4. Calculate Your Energy Needs
   The two figures you'll need to know are (a) your monthly or annual energy consumption, in kilowatt-hours, with seasonal variations, and (b) your peak power demand, in kilowatts, which is the maximum amount of power required at any one time.
   If you are presently connected to a public utility, your past electric bills will indicate your monthly energy consumption. If you do not have past electric bills, or if you are planning a completely energy-independent dwelling, then you can calculate your total consumption by listing all the lights and appliances you intend to use, together with their power ratings in kilowatts multiplied by the number of hours of use in the period, then adding these figures to establish your total energy consumption.
5. Independent or Interconnected?
   Decide at the outset whether you wish to be interconnected with, or independent from, your electric utility. If you choose to become, or remain, interconnected, then the utility becomes your energy storage bank: you buy electricity from the utility, or sell it back, according to your needs. In many cases, where relatively small amounts of electricity are traded, you may be allowed to buy and sell power at the same price. With this procedure, called "net billing", your electric meter runs forward or backward, depending on whether you are buying or selling power. In other cases, or when larger amounts of energy are traded, the utility will install two meters, one for incoming power, and one for the power you generate and sell to the utility. In this case, different rates are used to price the power you buy and the power you sell. One minor disadvantage of an interconnected power system is that in order to be connected into the utility grid, your system must automatically shut down in the event of grid failure (so you cannot feed power into a line under repair). This means that unless you design a system with a transfer switch and some energy storage capability, you cannot use your own power when the utility goes down.
   
   If you choose to be independent of the utility, or are so far away from existing power lines that it would cost more to connect to the utility than to install a private power system, then you need to consider the question of energy storage, such as charging batteries for electricity, with an inverter to produce ac power, pumping water up to a reservoir, or into a pressure tank, or by storing heat in water. One advantage of owning an independent power system is that no matter how high the electric rates increase in the future, you will never have to pay another utility bill!
6. If You Plan To Interconnect, First Contact Your Electric Utility
   Before designing a utility-interconnected power system, you need to contact the "NUG" (Non-Utility Generators) department of your utility company to determine their requirements for interconnection, contract terms and buy-back rates. Although all utilities are required by federal law to purchase power from small private power producers, it is usually necessary to sign a power purchase contract, which will also contain the technical requirements such as the fail-safe automatic disconnection of your system when the utility fails (plus a lockout switch accessible to the utility), and standards for power quality.
7. Other Important Points To Consider
   Electrical Wiring Standards: Whether you are considering an independent or interconnected system, your electrical installation must comply with the "National Electric Code". Even if you are planning only a very small dc-only system, wiring standards are important for safety and insurance concerns. Your municipal bylaws also address house wiring standards and inspections. As well, lightning protection and adequate grounding must be considered when designing your tower and wiring.

• AC, DC or Both: While a utility-interconnected system is ac only, an independent power system can provide dc power directly from batteries, or ac power through a stand-alone inverter, or even both together. It may be more economical to use direct dc power at higher than usual voltages, such as 24 or 48 volts, with a small inverter for appliances that only work on ac. If you contemplate powering an electric vehicle from your wind system, the higher voltage dc system would be required.
• Equipment Maintenance and Service Life: The service life of a modern residential wind turbine is twenty to twenty-five years, given normal annual maintenance. The annual cost of maintenance of a wind turbine and its electrical system is typically between 0.5-1.0% of the original cost of the system, or even less if you do all the work yourself.
• Combining Other Power Sources: Photovoltaic (solar electric) panels work very well when combined with wind energy. On a hot, windless July afternoon, you would have plenty of solar energy, whereas on a cold winter night, you would rely more on wind energy. You may also have access to other renewable energy resources, such as waterpower. A complete audit of your energy sources and uses will help you apply and manage your power production resources in the most efficient way. Remember, also, that the best source of energy source of all is conservation, which has no cost, no fuel, no pollution, and no maintenance!
• Installation, Instructions and Costs: The owner's manual furnished with each turbine provides complete installation and maintenance instructions. The final installed cost of a wind power system depends on how much of the work you can perform yourself. Local mechanical and electrical contractors can carry out any or all of the wind turbine installation tasks.   Unusual site conditions, the need for a higher tower, or a long cable run, can have an effect on the installed cost.
• Payback Period and Return on Investment: To calculate the payback period, and to determine which wind turbine will reliably supply your power needs, you will need to know your annual energy consumption and the site average wind speed. The final installed cost of the system includes the turbine (plus shipping), tower, wiring and electrical components including batteries and inverter, plus the local labor costs involved in installation. Once you know the installed cost of the system, this capital cost can be amortized over a twenty-five year period, adding maintenance and any financing costs, to arrive at a net monthly cost of the system.
  
  Then, to determine the payback period, obtain your utility's rate projections, if possible for the next twenty to twenty-five years. All large utilities maintain such projections, but can be somewhat reluctant to release them. Utility rate projections are generally regarded as extremely conservative (the actual rates will always be higher than projections), so you can be confident that your payback calculation will be "worst-case". Be sure to add to the energy rates the utility's "customer charges" as well as other costs and taxes that appear on your electric bill. In the deregulated electric power industry, you will have to pay two monthly bills, one from the actual generator of the power you use and another one from your local utility, for the use of its distribution system.
  
  Finally, using the grossed-up utility rates multiplied by your energy consumption, determine your monthly energy costs as if all your energy will be purchased through the utility. The simple payback period is how many months of projected utility bills are required to pay off the capital costs of your private power system. A more practical payback calculation is to offset the private power system costs against the utility on a monthly cash-flow basis; in this method, the payback period is defined as when the net cash flow from your using your private power system becomes positive.

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Wind Towers
One of the most difficult challenges of the installation of a wind turbine is assembling and erecting a tower. Fortunately, the engineers at Southwest Windpower have designed towers that are easy and safe to install. A number of heights for each product are available. Keep in mind, the larger the turbine the more complex the tower design. None of the towers require any kind of welding or machining and only the largest towers may require concrete. Most designs can be installed within a few hours to a day. All work with Southwest Windpower towers is done on the ground. You will NEVER need to climb a tower.

All of Southwest Windpowers tower kits include everything you need with the exception of:

• Pipe material
• Anchors
• wire

• To keep your costs low and to consider site variables, these components should be purchased locally. When selecting the materials for the construction of your tower, please consider the following:

• Pipe Material: For most conditions, we recommend a schedule 40 pipe material. This offers a wall thickness of .125” which is strong enough to resist most wind conditions.

• Anchors: The anchors are by far the most difficult part of installing a tower. There are various soil materials that you should consider prior to installing your tower. The type of anchor should also vary. Our owner's manuals have recommendations based on soil type.
• Wire: It is best to site your turbine as close to your batteries as realisitically possible to avoid losses in long runs of wire. It is also good to keep the wire guage down to a reasonable thickness to avoid cost. A 12V system will require very thick wire but a 24V or 48V uses smaller guage wire which allows for a more efficient system and is less expensive.

VERY IMPORTANT: Prior to the installation of your tower, read the owners manual thoroughly and make sure you understand the environmental conditions at your site prior to purchasing materials. We offer manuals that are free to download and review prior to purchase.