With America struggling to balance the need for more energy with mounting environmental concerns, many consider wind energy an attractive alternative to fossil fuels.
Now, with improved technology easing some of the drawbacks of wind power, harnessing wind has emerged as the world's fastest-growing energy source.
"The power in the wind can blow a semi-trailer truck off the road and flatten buildings. And it can be harnessed to be a non-polluting, never-ending source of energy to meet electric power needs around the world," according to a statement from the industry group American Wind Energy Association.
Wind is created by the sun, making wind another form of solar power. As the earth rotates and the sun heats the atmosphere, the hot air rises above cooler air, creating a current. The wind turns the blades of a turbine, which spins an internal shaft connected to a generator and makes electricity.
The Department of Energy compares a wind turbine to a fan but says that instead of using electricity to generate wind like a fan, a turbine uses wind to make electricity.
While there are disadvantages, the biggest being wind's intermittence, technological advancements continue to eliminate drawbacks and current wind research aims at addressing and finding solutions to the remaining challenges.
One of the greatest advantages of wind power is its abundance. The wind will always blow while nonrenewable Alternative Energy are subject to supply shortages and fluctuating prices, often caused by disruptions abroad. Advocates also argue that wind can help increase domestic energy security by decreasing the dependence on foreign sources.
The arguments appear to be working as wind power use in America is on the rise. In 2005, wind generated over 17 billion kilowatt-hours (kWh) annually, enough to power about 1.6 million homes. By the year 2020, wind could supply power to 25 million homes, or about 6 percent of total electricity used in the United States, according to the Department of Energy's Wind and Hydropower Technologies Program.
A small amount of land can supply large amounts of energy. The National Wind Technology Center estimates that good wind areas, which include 6 percent of the contiguous United States, have the potential to generate more than one and a half times the current electricity consumption of the United States.
Large wind farms with hundreds of turbines can produce enough energy to feed into an existing power grid while a single turbine can supply electricity to a homeowner in a remote location. Wind turbines require little space and can be incorporated on farms and ranches without displacing agriculture or pastures.
The most abundant winds blow in the Midwest and the Great Plains but more detailed wind maps produced by the National Wind Technology Center have helped expand wind-generating capacity throughout the United States. North Dakota is the windiest state, followed by Texas, Kansas, South Dakota and Montana, but through the use of technology, wind can be converted to energy in any state.
Of all renewable Alternative Energy, wind power has become the most economically competitive with fossil fuels and modern energy generation. In terms of cost, wind competes with new coal- or gas-fired power plants and its price is declining steadily due to increased research and technological advancements.
In the last 20 years, the cost of creating energy from wind has dropped 85 percent. According to the Department of Energy, advanced turbines have reduced the price from 80 cents per kWh to 4-6 cents today. The California Energy Commission's Energy Technology Status Report estimates that natural gas costs 3.9-4.4 cents/kWh, coal 4.8-5.5 cents, hydro 5.1-11.3 cents and nuclear 11.1-14.5 cents.
Incorporating hidden environmental costs into energy price makes wind power an even more attractive source because of its low environmental impact. The combustion process that converts fossil fuels into energy releases atmospheric emissions including carbon dioxide that are responsible for acid rain and global warming.
Wind, on the other hand, produces pollution-free electricity with no associated processing or shipping costs like those associated with other fuels. And unlike nuclear power, wind does not produce hazardous waste that requires careful storage and disposal.
But, despite all these advantages, wind doesn't blow all the time or blow when it's needed. And as with solar energy, it has limited storage capabilities. Charging batteries remains the only way to save wind energy for later. Also, most good wind sites are far from cities and large markets where demand for electricity is high.
Innovation has eliminated many disadvantages of the past such as erosion and noise. Careful design and proper landscaping can fix erosion problems and humming caused by the mechanical components of older turbines has been nearly eliminated, making today's wind farms much less noisy than in the past.
Despite the noise abatement, residents near proposed wind power sites sometimes express concerns over the loss of scenic views. Most onshore turbines need to be placed at visible areas in high elevations to capture stronger wind and offshore turbines will generally be noticeable from the shoreline because of transmission line limitations.
Because of this, many community members -- also called NIMBYs for Not in My Back Yard -- band together to fight wind power developments on the basis of aesthetics and environmental issues. The Save Our Sound Alliance to Protect Nantucket Sound campaigned against the Cape Wind project, the first U.S. offshore wind plant, that would put 130 wind turbines on Horseshoe Shoal in Massachusetts' Nantucket Sound in 2009.
The alliance, which is made up of politicians, tourist organizations, environmental groups, and businesses in the fishing industry, said the project, which has proposed to install turbines 400 feet high -- taller than the Statue of Liberty, the group notes -- within visible distance of the shore, will be "the industrial ruin of a pristine environment."
But Cape Wind says on a clear day, the turbines will appear just one-half inch above the horizon.
Animal rights issues also pose a concern. When addressing the threat to birds, proponents of wind projects say that while birds and bats occasionally collide with moving turbines, the overall impact on birds is very low. Nonetheless, environmental groups want developers to conduct more research on individual sites before they build.
The Humane Society of the United States said it hopes project planners choose sites with "an eye toward gaining the most energy with the smallest cost possible to wild animals and their habitats." The HSUS and the U.S. Fish and Wildlife Service recommend wind project developers conduct extensive research on the negative impacts on wildlife at each proposed site.
The HSUS is most concerned over the disruption of bird habitats, especially interferences with migration routes. The organization argues that changes in flight patterns to avoid turbines could "cause death in some birds who are migrating on stored fat and simply run out of energy sufficient to power their long trip."
With offshore wind projects, the impacts to sea life from underwater vibrations or the presence of the turbines' foundations are still under study. Regarding the Cape Wind project, the U.S. Coast Guard expressed concerns about offshore turbines becoming navigational hazards for small boats and rescue helicopters.
Both onshore and offshore turbines must be far enough off the ground to catch strong winds, meaning they need to comply with Federal Aviation Administration regulations requiring aircraft warning lights. The lights, opponents say, could be a nuisance to neighbors and may attract migratory birds. To fix the potential problem, the FAA is testing red lights that are non-disruptive and safe for airplanes.