Kevin Little Zack Paull Paul Kane Jeremy Callahan

How much electricity does an American home use? In 2008, the average annual electricity consumption for a U.S. residential utility customer was 11,040 kWh, an average of 920 kilowatt-hours (kWh) per month. Tennessee had the highest annual consumption at 15,624 kWh and Maine the lowest at 6,252 kWh.

Different Sizes Of Wind Turbines Wind turbines are available in a variety of sizes, and therefore power ratings. The largest machine has blades that span more than the length of a football field, stands 20 building stories high, and produces enough electricity to power 1,400 homes. A small home-sized wind machine has rotors between 8 and 25 feet in diameter and stands upwards of 30 feet and can supply the power needs of an all-electric home or small business. Utility-scale turbines range in size from 50 to 750 kilowatts. Single small turbines, below 50 kilowatts, are used for homes, telecommunications dishes, or water pumping.

Enviromental Impacts Noise Like all mechanical systems, wind turbines produce some noise when they operate. Most of the turbine noise is masked by the sound of the wind itself, and the turbines run only when the wind blows. In recent years, engineers have made design changes to reduce the noise from wind turbines. Early model turbines are generally noisier than most new and larger models. As wind turbines have become more efficient, more of the wind is converted into rotational torque and less into acoustic noise. Additionally, proper siting and insulating materials can be used to minimize noise impacts.

Enviromental Impacts Visual Impacts Because they must generally be sited in exposed places, wind turbines are often highly visible; however, being visible is not necessarily the same as being intrusive. Aesthetic issues are by their nature highly subjective. Proper siting decisions can help to avoid any aesthetic impacts to the landscape. One strategy being used to partially offset visual impacts is to site fewer turbines in any one location by using multiple locations and by using today's larger and more efficient models of wind turbines.

Enviromental Impacts Avian/Bat Mortality Bird and bat deaths are one of the most controversial biological issues related to wind turbines. The deaths of birds and bats at wind farm sites have raised concerns by fish and wildlife agencies and conservation groups. On the other hand, several large wind facilities have operated for years with only minor impacts on these animals. To try to address this issue, the wind industry and government agencies have sponsored research into collisions, relevant bird and bat behavior, mitigation measures, and appropriate study design protocols. In addition, project developers are required to collect data through monitoring efforts at existing and proposed wind energy sites. Careful site selection is needed to minimize fatalities and in some cases additional research may be needed to address bird and bat impact issues. While structures such as smokestacks, lighthouses, tall buildings, and radio and television towers have also been associated with bird and bat kills, bird and bat mortality is a serious concern for the wind industry.

Enviromental Impacts Other Concerns Unlike most other generation technologies, wind turbines do not use combustion to generate electricity, and hence don't produce air emissions. The only potentially toxic or hazardous materials are relatively small amounts of lubricating oils and hydraulic and insulating fluids. Therefore, contamination of surface or ground water or soils is highly unlikely. The primary health and safety considerations are related to blade movement and the presence of industrial equipment in areas potentially accessible to the public. An additional concern associated with wind turbines is potential interference with radar and telecommunication facilities. And like all electrical generating facilities, wind generators produce electric and magnetic fields.

Types of Wind Turbines Horizontal-axis Turbines Look Like Windmills Most wind machines being used today are the horizontal-axis type. Horizontal- axis wind machines have blades like airplane propellers. A typical horizontal wind machine stands as tall as a 20-story building and has three blades that span 200 feet across. The largest wind machines in the world have blades longer than a football field. Wind machines stand tall and wide to capture more wind. Vertical-axis Turbines Look Like Egg Beaters Vertical-axis wind machines have blades that go from top to bottom. The most common type — the Darrieus wind turbine, named after the French engineer Georges Darrieus who patented the design in 1931 — looks like a giant, two-bladed egg beater. This type of vertical wind machine typically stands 100 feet tall and 50 feet wide. Vertical-axis wind machines make up only a very small share of the wind machines used today.

Types of Wind Turbines Wind Power Plants Produce Electricity Wind power plants, or wind farms, as they are sometimes called, are clusters of wind machines used to produce electricity. A wind farm usually has dozens of wind machines scattered over a large area. The world's largest wind farm, the Horse Hollow Wind Energy Center in Texas, has 421 wind turbines that generate enough electricity to power 220,000 homes per year.

Important Links Year End Wind Power Capacity U.S. Wind Resource Map Diagram Of Wind Mill Workings

Bibliography "How much electricity does an American home use?." E.I.A.. us energy information administration, n.d. Web. 29 Mar "Wind Energy Basics." Wind Energy EIS Public Information Center. N.p., n.d. Web. 30 Mar "Wind Energy Development Environmental Concerns." Wind Energy EIS Public Information Center. N.p., n.d. Web. 30 Mar "Renewable Wind." E.I.A.. N.p., n.d. Web. 30 Mar