I thought i would post the typical Q&A regarding wind turbines. Very interesting stuff and hopefully you will have another outlook regarding this popular yet contraversal renewable energy source.

Noise:
Today's large wind turbines make less noise (about 45 decibels-dB) than the background noise you hear in your own home (50 dB)! According to the American Wind Energy Association (AWEA), today an operating wind farm at a distance of about 750 to 1,000 feet is no noisier than a kitchen refrigerator or a moderately quiet room. Careful placement of these turbines can justify this clean energy turbine.

Bird Kills:
Although birds do infrequently collide with turbines, wind energy poses less of a threat to birds than many other commonplace structures. In fact, the National Audubon Society has stated that it supports the development and use of wind power. Based on numerous studies that have taken place in New York, Oregon, Vermont, Colorado, Wyoming, Minnesota, and California, collision with turbines result in 1-2 bird deaths or less per turbine per year. For comparison, each year at least 60 million birds die in collisions with vehicles; at least 98 million in collisions with buildings and windows; and at least 4 million in collisions with communication towers. Important consideration should be given to placement of wind turbines to ensure that turbines are not located along migratory bird flight paths or the flight paths of threatened or rare species. In another study, it has been estimated that the combined ordinary American house cats worldwide kills between 100-200 million birds, compared to 33,000 birds killed by Wind farm collisions worldwide.

The alternatives:
Consider this; bird deaths that result from fossil energy based power production:
Tall smokestacks- A study at a single Florida coal fired power plant with four smokestacks recorded an estimated 3,000 bird kills in a single night during a fall migration.
Oil spills at sea - In a single oil shipping accident, - the Exxon Valdez oil spill in Alaska's Prince William Sound - more than 500,000 migratory birds perished, or about 1,000 times the estimated annual total in California's wind power plants.
Additional threats to birds from other energy sources include: mercury emissions from coal fired power plants; global climate change resulting from the combustion of fossil fuels; acid rain resulting from coal fired power plant emissions of SO2 and NOx and; destruction of habitat as a result of mining activities associated with the coal, gas, oil and uranium industries.

Property Values:
Views of wind turbines will not negatively impact property values. A recent study on the economic impacts of wind power states that, "based on a nation-wide survey conducted of tax assessors in other areas with wind power projects, we found no evidence supporting the claim that views of wind farms decrease property values." Other studies conducted in both the US and abroad, have made similar findings.

Opposition to wind energy projects?
Local opposition to proposed wind farms usually arises because some people perceive that the development will ruin the view that they are use to. It is true that a large wind farm can be a significant change, but while some people express concern about the effect wind turbines have on the beauty of our landscape, others see them as elegant and beautiful, or symbols of a better, less polluted future. The visual effect of wind farms is a subjective issue, but most of the other criticisms made about wind energy today are exaggerated or untrue, and simply reflect attempts by particular groups to discredit the technology, worry local communities, and turn them against proposed projects. With the internet these negativity spread like crazy.

Tourism and Income:
In North Carolina, a study to determine public attitudes towards wind energy was recently conducted. The study found that 77.1% of participants who had seen first hand a utility scale turbine said that they liked its appearance. 7 Studies from numerous US states and other countries report that a majority of people think wind turbines are graceful, elegant structures. Many people find turbines to be interesting features in the landscape, enhancing the vista overall. In the UK, the British Wind Energy Association notes that wind farms are popular tourist attractions, with thousands of people each year flocking to visit attractions. This could certainly give Hamlin added revenue for local merchants.

Pollution Prevention:
A single 750 kilowatt wind turbine, operated for one year at a site with Class 4 wind speeds, can be expected to displace a total of 2,697,175 pounds of CO2, 14,172 pounds of sulfur dioxide, and 8,688 pounds of NOx.

Wind energy is economically competitive.

With today’s rising coal and gas prices, new wind plants compete favorably against any new electricity generation source. In fact, when the Colorado Public Service Commission issued a ruling on the 161-megawatt (MW) wind project in Lamar, Colorado, the commission determined that wind energy provided the lowest cost of any generation resource submitted to a solicitation bid by Xcel Energy. The commission also noted that unlike the other generation resources considered, the Lamar project avoided a future risk of increased fuel prices.

Wind energy is a valuable crop of the future for farmers and ranchers.
Wind farms located in rural areas generate energy that can be transmitted to load centers in urban areas via the regional utility grid. The rural areas retain the jobs, as well as land lease revenue for farmers and ranchers (as much as $4000 per turbine per year). Wind turbines are compatible with rural land uses—crops can be grown and livestock can be grazed up to the base of the turbine. Wind energy also provides an increased local tax base for rural areas. One wind project increased its local tax base by $32 million. The 912 MW of new wind power installed in Texas in 2001 will deliver $13.3 million in tax revenue for schools and counties.

Unlike most other electricity generation sources, wind turbines don’t consume water.
Irrigation and thermal electric generation account for approximately 77% of U.S. fresh water use. Conventional plants generating power from fossil and nuclear fuels use large amounts of water for cooling; wind turbines do not use water. That makes wind energy a great choice for farm lands.
Wind energy is an indigenous, renewable energy source that contributes to national security.
The United States is the world’s largest importer of oil and natural gas, which often originate in troubled areas of the world. The Great Plains region, which has been dubbed “the Saudi Arabia of wind” because of its tremendous untapped wind energy potential, offers home grown energy, which increases national security. Reliance on indigenous resources also reduces the balance of payments that threatens our national economic security. Because of the distributed aspect of wind energy, it is less vulnerable than large liquefied natural gas (LNG) ports or large thermoelectric power plants.
Shadow Flicker
Wind turbines, like other tall structures will cast a shadow on the neighboring area when the sun is visible. If you live very close to the wind turbine, it may be annoying if the rotor blades chop the sunlight, causing a flickering (blinking) effect while the rotor is in motion.
A bit of careful planning, and the use of good software to plan your wind turbine site can help you resolve this problem, however. If you know where the potential flicker effect is of a certain size, you may be able to place the turbines to avoid any major inconvenience for the neighbors.
This is occasionally raised as an issue by close neighbors of wind farm projects. A wind turbine's moving blades can cast a moving shadow on a nearby residence, depending on the time of the year (which determines how low the sun is in the sky) and time of day. It is possible to calculate very precisely whether a flickering shadow will in fact fall on a given location near a wind farm, and how many hours in a year it will do so. Therefore, it should be easy to determine whether this is a potential problem. Normally, it should not be a problem in the U.S., because at U.S. latitudes (except in Alaska) the sun's angle is not very low in the sky, and the appropriate setback for noise will be sufficient to prevent shadow flicker problems.
Fortunately, we are able to predict quite accurately the probability of when and for how long there may be a flicker effect. We may not know in advance whether there is wind, or what the wind direction is, but using astronomy and trigonometry we can compute either a likely, or a "worst case" scenario, i.e. a situation where there is always sunshine, when the wind is blowing all the time, and when the wind and the turbine rotor keep tracking the sun by yawing the turbine exactly as the sun moves.
What about turbines throwing blades, or ice? Is wind energy dangerous to the public?
It has been estimated by a number of reliable sources that 50,000 Americans a year die from air pollution, of which about one-third is produced by power plants. By contrast, in 20 years of operation, the wind industry (which emits no pollutants) has recorded only one death of a member of the public--a German skydiver who parachuted off-course into an operating wind plant. Blade throws were common in the industry's early years, but are unheard of-today because of better turbine design and engineering. Ice throw, while it can occur, is of little danger because setbacks typically required to minimize noise (see above) are sufficient to protect against danger to the public, and because ice buildup slows a turbine's rotation and will be sensed by a turbine's control system, causing the turbine to shut down. One European group that has investigated the ice throw question recommends a setback of 1.5 times the sum of a turbine's hub height and its rotor diameter.
How much water do wind turbines use compared with conventional power plants?
Water use can be a significant issue in energy production, particularly in areas where water is scarce, as conventional power plants use large amounts of water for the condensing portion of the thermodynamic cycle. For coal plants, water is also used to clean and process fuel.
According to the California Energy Commission (cited in Paul Gipe's Wind Energy Comes of Age, John Wiley & Sons, 1995), conventional power plants consume the following amounts of water (through evaporative loss, not including water that is recaptured and treated for further use):
WATER CONSUMPTION--CONVENTIONAL POWER PLANTS

Technology
gallons/kWh
liters/kWh

Nuclear
0.62
2.30

Coal
0.49
1.90

Oil
0.43
1.60

Combined Cycle Gas
0.25
0.95




Small amounts of water are used to clean wind turbine rotor blades in arid climates (where rainfall does not keep the blades clean). The purpose of blade cleaning is to eliminate dust and insect buildup, which otherwise deforms the shape of the airfoil and degrades performance.

Similarly, small amounts of water are used to clean photovoltaic (solar) panels. Water use numbers for these two technologies are as follows:

WATER CONSUMPTION--WIND AND SOLAR

Technology
gallons/kWh
liters/kWh

Wind [1]
0.001
0.004

Solar [2]
0.030
0.110

Attached Images

commercial-wind-turbine-schematic.jpg (22.9 KB, 0 views)

Pictured attached is a cut away image showing the inside workings of a commercial wind turbine generator. Though large in size, such wind turbines are still very simple with relatively few components. Such simplicity is essential if the wind turbine is to be kept operational through years of extreme conditions.




Three turbine blades (1) make up the rotor. The pitch (3) of each blade can be changed (i.e. the blade can be rotated) to increase efficiency in low winds and to decrease efficiency (to protect the wind turbine) in very strong winds. In addition a brake (4) is fitted which can be set when dangerously strong winds are approaching or when the turbine is taken down for maintenance.

The rotor is spun by the wind causing the low-speed shaft (5) to rotate. This rotation is then passed onto the high-speed shaft (12) via a gearbox (6) which accelerates the speed of rotation to the levels necessary to generate high voltage electricity with the generator (7).

Everything is controlled via an electronic controller (8) which takes data inputs from an anemometer (9) which measures the speed of the wind, and a wind vane (10) which detects the direction of the wind. The nacelle (11) - the sealed unit at the top of the tower (15) - can then be automatically rotated to face into the wind with a yaw motor (14) turning the yaw drive (13).

Attached Images

commercial-wind-turbine-schematic.jpg (22.9 KB, 0 views)