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How Wind Works
How much do wind turbines cost?
How big are wind turbines?
Are wind turbines noisy?
Do wind turbines harm wildlife?
Is wind energy expensive?
What is the status of the wind energy market in the United States?
What is Net Metering and Net Billing?
What are the advantages and disadvantages of connecting my wind system to the utility grid?
How do I measure the wind resource on my land?



How Wind Works

Home wind turbines are simple machines with only a few moving parts. The wind turns the blades which turn the shaft which drive the generator, creating electricity.

Turbine systems generally include:

• Blades (or rotor) which convert the wind's kinetic energy into rotational energy
• Nacelle (an enclosure) which contains a drive train, usually including a gearbox and a generator. This is where the rotational energy is converted to electrical energy
• Tower to support the blades and nacelle
• Electric equipment such as controls, electrical cables, ground support equipment, and interconnection equipment

The faster the wind speed and the larger the area covered by the blades, the more electricity generated. A 2.5-kilowatt wind turbine (with rotors four to five meters or 14 feet in diameter) can generate about 3,000 kilowatthour annually at a site with wind speeds averaging 10 miles per hour, or about enough to meet half the electricity needs of a typical household.

A 2.5-kilowatt machine atop a 100 foot tower might cost $20,000 installed. However, many states offer tax credits or other incentives and policies (such as net metering) to make home wind more affordable.

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Q: How much do wind turbines cost?

A: Wind turbines come in many shapes and sizes, but here is a rule of thumb on how much they cost Wind turbines have significant economies of scale. A large-scale wind turbine (i.e., greater than 600 kilowatts) costs approximately $1,000/kilowatt of nameplate capacity. That means a hypothetical 1,000 killowatts (1 megawatt) turbine will cost approximately $1 million fully installed.

Smaller farm or residential scale turbines cost less overall, but are more expensive per kilowatt of energy producing capacity. Wind turbines under 100 kilowatts cost roughly $3,000 to $5,000 per kilowatt of capacity. That means a 10 kilowatt machine (the size needed to power an average home) might cost $35,000-$40,000.

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Q: How big are wind turbines?

A: Wind turbines range in size from tiny micro turbines, to enormous utility scale power production facilities. Large turbines have rotor diameters of 50 to 90 meters. The tip of the blades might reach as high as 135 meters (442 ft) in the air. Smaller turbines are usually placed on 30 to 40 meter towers. (See Windustry's related graphic: The Scale of Wind Power)

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Q: Are wind turbines noisy?

A: On a windy day, the sound of the turbine is drowned out by the wind even just a short distance from the turbine. Current technology makes noise almost a non-issue at most wind farms. However, wind turbines do produce some sound, which means wind farms should be sited with this in mind.

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Q: Do wind turbines harm wildlife?

A: Birds and bats occasionally collide with turbines, as they do with any tall structure. A few older wind projects have raised concerns about bird impacts because they were built in areas with sensitive raptor populations. Careful siting and wildlife studies make it possible to avoid most wildlife problems.

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Q: Is wind energy expensive?

A: Wind energy is the cheapest form of new electricity generation available today. Wind power is more expensive than power from old, established power plants, but is cost competitive with any new power plant. Technology innovations and market building incentives have helped to dramatically lower costs over the last 20 years.

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Q: What is the status of the wind energy market in the United States?

A: Wind is the fastest growing energy source in the world, expanding at a rate of 20-30% per year. The United States had a record year for new wind in 2005, with more than 2,400 megawatts of new wind energy installations. This brings the national total to 9,149 megawatts of installed wind energy, enough to power 2.3 million homes. The outlook for United States growth in 2006 is bright as the industry in on course to bring over 3,000 new megawatts on-line over the year.

California remains the nationwide leader in installed capacity with 2,150 megawatts, but Texas is rapidly catching up with 1,995 megawatts. Iowa is in third place with 836 megawatts and Minnesota added 129 megawatts in 2005, putting Virginia in fourth place with 744 megawatts. Minnesota continues to lead the country in community, farmer, and locally-owned wind projects.

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Q: What is Net Metering and Net Billing?

A: The concept of net metering programs is to allow utility customers to generate their own electricity from renewable resources, such as small wind turbines and rooftop solar systems. The customers send excess electricity back to the utility when their wind system, for example, produces more power than needed.

Customers can then get power from the utility when their wind system doesn't produce enough power. In effect, net metering allows the interconnected customer to use the electrical grid as a storage battery. This helps customers get higher (retail) value for more of their self-generated electricity.

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Q: What are the advantages and disadvantages of connecting my wind system to the utility grid?

A: The advantages of utility interconnection include having standard utility AC power when you need it, not just when the wind blows; eliminating the need for storing excess electricity in batteries, which can be expensive; and you only pay for the net electricity used. One disadvantage of net metering and net billing may be the cost of the interconnection, which can vary considerably from utility to utility. There are efforts to get standards in place for interconnection guidelines.

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Q: How do I measure the wind resource on my land?

A: Wind assessment takes place at a number of different levels: consulting a wind map, obtaining previously measured data, and taking your own measurements. The cheapest and easiest way to assess your resource is to consult a wind map.

It is important, however, to remember that wind maps are not always detailed to the level of individual homesteads and there are many factors, such as hills, buildings, and trees that may further cause variances from the map. Nevertheless, it is a good place to start to get a general idea of your resource and to do some basic economic analysis.

The next step is to obtain data that has already been measured by other groups in your area. Airports, for example, keep track of wind speeds in their area.

Finally, you can measure your own wind speed by installing a device called an anemometer. DEQ and partners are currently administering a state anemometer loan program free to the general public. A total of eight 20-meter anemometers are currently deployed out in the field. Contact the local branch of the DEQ to find out if there is a loan program in your area.

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