Alternative energy, Part 4–Wind power
By Dan Slattery
Wind power is not for everyone, everywhere. It is very site specific. Effectiveness depends greatly upon whether youre in the city, in an open rural area, your specific terrain, buildings, trees, etc. The height of a wind turbine generator is important, toowind speeds are generally greater at 100 feet than they are at ground level. Also important are your average monthly and average annual wind speeds, in miles per hour (mph) and meters per second (m/s). This is how performance of wind generators is gauged.
You can approach this in different ways. Efficiency in the technology of wind generators has improved greatly over the years. For example, the Air 403 by Southwest Wind power has an output of 400 watts at 28 mph or 12.5 m/s, a total rotor diameter of only 46 inches, weighs only 13 lbs., has a selectable output of 12, 24 or 48 VDC (volts, direct current), automatic internal regulation, can be installed in only a couple of hours, has only two moving parts, requires no maintenance, and has a list price of only $595.
This unit, or one like it, would be ideal for a small- to medium-size backup home power system; a hybridsystem fed by a wind generator, solar panel array, with batter backup, and an inverter. Well look at system design and installation later in this series.
It is also an ideal unit for boats or RVs, to charge your batteries, run your lights and accessories, or even pump your home water from a well. No specific wind information is necessary for such a simple unit and simple approach. Forty years ago, there was a TV antenna on every rooftop. Why not a small wind generator? Aesthetically, it looks much like a weather vane, only slightly larger.
On the other hand, you can get real serious about this real quick. If you want to be completely electrically independent (off the grid) and/or sell the excess power you generate back to your local utility company (where applicable), there are wind generators available at power levels as high as 10,000 watts (10 KW). Two of these, and youll be flying high, literally.
Your home uses appliances that operate at 120 VAC (volts, alternating current). The average home has 100 amp service from the utility companysometimes more, sometimes less. Herein lies the supply and demand factor. To determine your energy needs, do the mathmultiply the current draw (in amperes or amps) of the appliance by 120 volts. This gives you its power consumption (in wattage, or watts).
Examplesupply (your home) 120V X 100A = 12,000 watts (12 KW)
Exampledemand (refrigerator) 120V X 4.5A = 540 watts (.54 KW).
Get the picture? Obviously, no one runs every appliance in their home 24 hours a day. Your energy needs will vary according to your lifestyle. The more frugal you are, the less costly the energy.
The problems with this approach are the up-front costs. Generally, these kinds of systems, all things included (controller electronics, towers, wiring, etc.) can run anywhere from $10,000 to $35,000.
But say, just as an example, you live in the same home for 10 years. Your average electrical bill is $100 monthly. $100 X 12 months X 10 years = $12,000. Youve already spent $12,000, you dont own the equipment, youre not generating any excess power to sell back to anyone, and youre subject to shortages, brownouts and blackouts. The up-front cost is problematic, but you can start on a smaller, less costly scale, and still experience immediate energy savings.
Putting up a tower in the city can be problematic, too. Winnebago County, however, is less restrictive about rural areas. They simply require that a 100-foot tower be placed on a minimal 2-1/2 acre lot, the base being no less than 110 feet from each lot line in any direction.
The city of Rockford, however, is a little more stringent. According to Joe Zimmer, architect for the City of Rockford Building Department, the following criteria must be met:
1. Check city building code information that applies. You may have to file for adopted code if necessary. Also check on Illinois state building codes.
2. Talk to your neighbors. If theyre cool, check your zoning ordinance. Apply for a zoning variance if necessary.
3. Tower and system installation must comply with U.S. national electrical code as of 1996 as well as international mechanical code as of 1996.
4. Tower should be OKd by an architect or a structural engineer.
5. Complete structure must be able to withstand established basic wind speed of 80 mph.
Piece of cake, right? Sure! (as if). But remember, you dont have to put up a 100-foot tower to enjoy the energy savings of wind power. You can start small and build from there through time. Chances are, no one will bat an eye at that weather vane on your roof.
For more information on wind power products, system design, installation and accessories, you can contact the following organizations:
Bergey Windpower Co., 1-405-364-4212
Ecology Services/Emerald Energy, LLC, 1-262-646-4664
Energy Outfitters, Ltd., 1-800-467-6527
Innovative Power Systems, Inc., 1-612-623-3246
Southwest Windpower, 1-520-779-9463