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Cedar Ridge Wind TurbineAlliant Energy is committed to providing our customers with balanced energy solutions that are environmentally responsible, reliable and cost effective.

Alliant Energy subsidiaries Interstate Power and Light Company (IPL) and Wisconsin Power and Light Company (WPL) combined have a generation portfolio that includes nearly 1,200 megawatts of generated renewable and alternative energy sources. Most of that comes from wind generators across Iowa, southern Minnesota and Wisconsin, with a small amount from biomass and biogas.

We generate and acquire energy from renewable sources beyond our renewable portfolio standards; however, renewable energy above and beyond those requirements may be sold for Renewable Energy Credits.

WPL owns and operates two wind farms. The Cedar Ridge Wind Farm, located in Fond du Lac County, Wisconsin, began commercial operation in December 2008. The Bent Tree Wind Farm in Freeborn County, Minnesota began commercial operation in February 2011. IPL owns and operates the Whispering Willow Wind Farm in Franklin County, Iowa. It began commercial operation in December 2009.

Read on to learn more about Alliant Energy’s existing wind generation facilities.

Wind Power and Wind Farms

What is a wind farm?
A wind farm is a grouping of wind turbines that spin when the wind blows to produce electricity.

How does a wind turbine work?
A wind turbine uses the power of the wind to generate electricity. The spinning motion of the turbine’s blades turns an electric generator inside the turbine’s casing, which interacts with a magnet to create electrical current.

See a U.S. Department of Energy animation of how a wind turbine works.

How does wind power get to the electric grid?
Typically, electricity generated by the wind passes through the wind turbine’s base and joins electricity from the other wind turbines via an underground system of cables, or collection system. The collection system brings all the electricity to a substation, which loads the electricity onto transmission lines to carry the power over short and long distances to customers.

Do wind turbines use any fuel?
No. Wind turbines operate solely on the wind.

What are wind turbines made of?
The towers are tubular and made of steel. The blades are made of fiberglass-reinforced polyester or wood-epoxy.

How big is a wind turbine?
Wind turbines used for large-scale wind farms come in various sizes, but are usually approximately 13 feet wide at the base, and between 230 and 265 feet tall at the hub. With one of the blades in the upright position, the total height is approximately 406 feet.

What is “capacity factor?”
Capacity factor is one way to measure productivity of a generating source. It compares a generator’s actual production over a period of time with the amount of power the generator could produce if it ran at full capacity for the same amount of time.

What is a typical capacity factor for a wind turbine?
Because the wind does not blow steadily all the time, a capacity factor of 25 to 40 percent is not uncommon for a wind turbine. For the Cedar Ridge site, capacity factor is estimated to be approximately 30 to 35 percent.

What is a typical availability factor for a wind turbine?
Most modern wind turbines have an availability factor of more than 95%. This is higher than many types of generators, including most power plants. Availability factor refers to the percentage of time a generator is able to generate.

Why can’t we meet all our electricity needs with wind power?
Because the wind doesn’t blow all the time, it would be unwise to rely on wind power to meet all our electricity needs. Fossil-fuel generation is still the least-cost, most reliable way to meet our electricity needs, but wind plays a big role in offsetting the need for additional fossil fuel generating plants.

Benefits of wind power

Wind energy provides emissions-free electricity that is both economical and environmentally friendly.

Economic Benefits – Wind is one of the least expensive sources of new, large-scale electricity generation. As the fuel (wind) is free of cost, wind energy provides a stable price for wind power generation. In addition, federal production tax credits which are currently available make new wind farm construction even more economical.

  • Provides economical development – Wind energy production can diversify agricultural economies and add to the tax base. Wind energy projects keep more energy dollars in the local communities where the projects are located and provide a steady income to land owners.
  • Supports agriculture – Wind turbines installed in pastures have no harmful effects on people, crop production or livestock grazing. Wind farms are spaced over a geographic area, but their real footprint covers only a small portion of the farmland.

Clean – Wind energy provides electricity that is free of air emissions or hazardous waste. Using wind energy avoids the contaminations of greenhouse gases and decreases the amount of smog and acid rain caused by fossil fuels.

Renewable – Wind energy is completely renewable and sustainable. Wind is readily available and using wind does not decrease the natural resources of the world.

Reliability – Wind energy systems require minimal maintenance and have low operating expenses. Wind turbines are very reliable and are available for generating electricity 95% of the time.