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Fossil Fuels
   • History
   • How it Works
   • Efficiency
   • Benefits
   • Limitations
   • Geography
   • Sources

One of the most important alternative energy resources can’t be seen or touched, but its power is obvious to anyone who’s ever weathered a hurricane, a tornado, or even a strong storm. At its worst, wind can wreak havoc, destroying everything in its path. At its best, it’s a source of clean, efficient, inexpensive energy. Explore more about ways to harvest the power of the wind.

wind farmThe sun heats up the atmosphere, which causes it to expand. As the atmosphere expands it moves cooler air out of the way. The movement of these hot and cold air currents is what makes up wind. Because wind is moving all of the time, it is a type of kinetic energy we can use if we are able to harness it.

People have used the wind’s power for thousands of years. Wind powered mills used to grind grain and to pump water. Wind was a primary power source up until the Industrial Revolution, when its importance decreased dramatically. Inventions like the steam engine and steam turbine provided cheaper and more reliable power sources. Energy created by steam fulfilled an ever-increasing demand for electricity, blowing away wind’s leading role as a power source.

How it Works
Wind is part of the cycle of energy that starts with the sun itself. The sun’s energy heats the earth’s surface unevenly. Warmer air rises drawing in cooler air and resulting in wind. The way we capture the energy of the wind hasn’t changed much since the very first windmills turned. We still use turbines, but instead of using the wind’s energy to do work like grinding grain or pumping water, wind’s energy is now used to produce electricity. The force of the wind turns the blades of a turbine. The turbine is attached to a generator, which spins, producing electricity . In order to produce electricity on a large scale, groups of turbines are placed together in arrays called wind farms.

Not all of the wind’s potential energy can be extracted during the electrical generation process. The amount of energy available in a resource compared to the amount of energy actually extracted, is the efficiency of that resource. In wind’s case, it’s maximum efficiency is about 59%. Physical factors defined as the Betz limit mean not all the energy can be captured. While the basic process hasn’t changed since the earliest windmill blades turned, changes have occurred allowing for improved efficiency. Better blade design and lighter and stronger materials mean more energy extraction. The current turbine designs allow for 35-45% efficiency, leaving room to reach the maximum efficiency of 59%. That improvement should come as designs and materials develop even further.

Wind power has many benefits

  • Environmental: Like many other renewable resources, the wind contributes no emissions or waste to the environment. By using wind power instead of burning coal for example, 1 billion pounds of C02 can be kept out of the atmosphere.
  • Economic: For power companies, the wind is essentially a "free" fuel. It doesn’t need to be purchased or transported. The cost comes in the form of the turbines. For farmers, wind can provide a new source of income, as power companies often pay "rent" to place turbines on tracts of land in windy regions. Since a wind turbine takes up only about a half an acre, the land is doing double duty for the farmer who is harvesting two "crops" from the same land. For communities, wind farms can provide important economic development. Many wind farms are built in rural areas, and provide good-paying jobs for residents.

So why isn’t everyone exploiting this "free" resource?

  • SpeedOne of the main limitations of wind power is that the wind doesn't blow fast enough all of the time. Since wind speed directly affects power output, you end up with unpredictable power levels.
  • ReliabilityYou simply can’t control whether the wind will blow. No wind, no power.
  • StorageCurrently, electricity can’t be stored efficiently, so wind power can’t be relied on as a power source free of interruptions.
    Beyond the control factors, are aesthetic ones.
  • LooksNot everyone looks at a wind farm and sees the energy potential. Instead they see a cluttered and unattractive landscape.
  • NoiseCritics also point to the noise level created by wind farms. Some people don’t notice the noise, to others it’s bothersome.
  • Danger—A widely held belief, that’s scientifically unsupported, is that wind turbines kill a lot of birds. Studies have shown that electric lines actually kill more birds than turbines do, although it would be unwise to site a wind farm in a migratory path.

Geographical Considerations
When it comes to energy production, the wind is considered a resource that’s specific to certain areas. Just like Texas is rich in oil, the upper Midwest is rich in wind. The wind is constant enough and at a high-enough speed to make wind farming sensible and economically efficient for that region.

Check it out!
Check this link for a map of average annual wind power in areas of the United States from the Renewable Resource Data Center.

Several factors have to be taken into consideration when considering if a site is a good choice for a wind farm.

  • Wind speedDoes the wind blow fast enough and consistently enough to produce power?
  • The physical landscape is also taken into consideration. The best place to site a turbine is on top of a ridge or hill, so that it’s capturing the most wind possible.
  • Access to the electrical gridAre there transmission lines close enough to the turbines to distribute the electricity generated? Many of the places richest in wind are extremely rural, and the electrical grid might be far away.

What do you think?
Some people think wind turbines are ugly. Others find them beautiful. What is your opinion? Should the appearance of wind farms limit where they are used? Can wind power play a significant role in meeting our future energy needs?


  1. American Wind Energy Association. "Iowa School District to Receive Wind Energy for Christmas." (Online) http://www.awea.org/wew/828-1.html. June 2001.
  2. American Wind Energy Association. "Vast Wind Potential in the Great Plains." (Online) http://www.awea.org/outlook2000/outlook_8.html. July 2001.
  3. Solarbuzz Inc. "Solar Energy Industry Statistics: Market Share." (Online) http://www.solarbuzz.com/StatsMarketShare.htm. July 2001.





Not in My Backyard….
It’s easy to claim to support renewable energy resources like wind power. But showing that support often means making tough decisions. Take the proposed project off the coast of Cape Cod. More

Iowa Schools Use Wind Power
Several Iowa schools learned a lesson about lessening their energy bills, by installing wind turbines. The clean, efficient generators help schools save money and contribute to the classrooms as well.

World Class Wind
One of Iowa’s claims to fame is as home to the world’s largest wind farm.

IPTV Market to Market Links

Benefit found in small scale wind projects
wind researchers have often called the upper Midwest the Saudi Arabia of wind power. If the wind potential for the entire region were completely utilized, it is estimated the energy produced would supply more power than the entire united states could use.

Experts discuss Wind power.

Web Links
Largest Land-based Wind Project will be Built in Iowa
Midamerican Energy plans to build 310 megawatts of wind generation facilities in northwest or north-central Iowa by 2006. The $323 million project will be the largest land-based wind project in the world, according to the U.S. Department of Energy.

Iowa Wind Energy Development Projects
Keep up-to-date with current and new wind projects in the State of Iowa.

What are the average wind speeds each month in Iowa
The answer is blowin' in the wind. See full color maps illustrating usable wind speeds.