Frequently Asked Questions About Wind Energy

How much electricity can one turbine generate?
Do wind turbines really save energy?
Are wind turbines reliable?
Do wind turbines bother wildlife?
How much energy can wind realistically supply to the U.S.?
How much land is required to site wind turbines?
In what ways does wind energy benefit the economy?
What are America's current sources of electricity?
What are the environmental benefits of wind power?

How much electricity can one turbine generate?
The ability to generate electricity is measured in watts. Watts are very small units, so the terms kilowatt (kW, 1,000 watts), megawatt (MW, 1 million watts), and gigawatt (pronounced "jig-a-watt," GW, 1 billion watts) are most commonly used to describe the capacity of generating units like wind turbines or other power plants.

Electricity production and consumption are most commonly measured in kilowatt-hours (kWh). A kilowatt-hour means one kilowatt (1,000 watts) of electricity produced or consumed for one hour. One 50-watt light bulb left on for 20 hours consumes one kilowatt-hour of electricity (50 watts x 20 hours = 1,000 watt-hours = 1 kilowatt-hour).

The output of a wind turbine depends on the turbine's size and the wind's speed through the rotor. Wind turbines being manufactured now have power ratings ranging from 250 watts to 1.8 megawatts (MW).

Example: A 10-kW wind turbine can generate about 10,000 kWh annually at a site with wind speeds averaging 12 miles per hour, or about enough to power a typical household. A 1.8-MW turbine can produce more than 5.2 million kWh in a year--enough to power more than 500 households. The average U.S. household consumes about 10,000 kWh of electricity each year.

Do wind turbines really save energy?
On average it takes only 6 months for a wind turbine to recover all the energy required to build and operate it. Wind turbines use energy from the moving air to generate electricity. Therefore, a modern 1.5 MW wind turbine will displace emissions other electricity sources, often coal-fired power stations. For example, a 1.5 MW turbine will annually displace 3000 tons of carbon dioxide generated by traditional electricity sources.

Are wind turbines reliable?
Yes. High-quality modern wind turbines have an availability factor above 98% (i.e., the turbines are on average ready to run during more than 98% of the hours of the year). This availability factor is beyond that of any other electricity generating technology. Modern wind turbines require maintenance checks every six months and are built to very exacting industrial standards.

Do wind turbines bother wildlife?
Deer and cattle habitually graze under wind turbines, and sheep seek shelter around them. While birds tend to collide with structures such as electrical power lines, guy wires, masts, or buildings, they are very rarely affected directly by wind turbines. Wind's overall impact on birds is low compared with other human-related sources of avian mortality, such as hunters, house cats, buildings, and autos. The wind industry is working with environmental groups, federal and state regulators, and other interested parties to develop methods of measuring and mitigating wind energy's effect on birds.

How much energy can wind realistically supply to the U.S.?
Wind energy could supply about 20% of the nation's electricity, according to Battelle Pacific Northwest Laboratory, a federal research lab. Wind energy resources useful for generating electricity can be found in nearly every state.

How much land is required to site wind turbines?
Wind turbines and access roads occupy less than 3% of the land area in a typical wind farm. The remaining land can still be used for farming or ranching without inconvenience. Since wind turbines extract energy from the wind, there is less energy in the wind shade of a turbine (and more turbulence) than in front of it. In a wind farm, turbines generally have to be spaced between three and nine rotor diameters apart in order not to shade one another too much. If there is one particular prevailing wind direction, turbines may be spaced very closely in an orientation that is at a right angle to that direction to avoid shading. For instance, if the prevailing wind blows from the west, turbines may be placed north-south.

In what ways does wind energy benefit the economy?
Wind farms can revitalize the economy of rural communities, providing steady income through lease or royalty payments to ranchers and other landowners. An average estimate for income to a landowner from a single wind turbine is roughly $5,000 a year.

What are America's current sources of electricity?
Coal is currently used to generate more than half of all of the electricity (52%) used in the United States. Other sources of electricity are: natural gas (16%), oil (3%), nuclear (20%), and hydropower (7%).

What are the environmental benefits of wind power?
Wind energy system operations do not generate air or water emissions and do not produce hazardous waste. They do not deplete natural resources such as coal, oil or gas, or cause environmental damage through extraction and exportation. Wind's pollution-free electricity can help reduce the environmental damage caused by power generation in the U.S. and worldwide.

Another benefit of wind power, both economical and environmental, is the reduction of hidden costs. Several studies have estimated that 50,000 Americans die prematurely each year because of air pollution.