Alliant Energy’s First Wind Farm in Iowa Begins Operation

With construction completed, Interstate Power and Light Company (IPL), a subsidiary of Alliant Energy Corporation (NYSE: LNT), has initiated commercial operation of its first owned-and-operated wind farm in Iowa. The Whispering Willow Wind Farm-East in Franklin County, Iowa, is capable of generating up to 200 megawatts of emissions-free wind energy for its customers – enough to power approximately 50,000 homes.

"This is an important day for our company, electric customers and the environment as we continue to strive to meet the increasing demand for green energy," said Bill Harvey, Chairman, President and Chief Executive Officer for Alliant Energy. "We believe the addition of Whispering Willow Wind Farm-East to our renewable energy portfolio moves us further down the path to a greener energy future."

The company expects that over the next 20 years, the Whispering Willow Wind Farm-East will offset approximately 2 million tons of carbon dioxide, 2,600 tons of nitrogen oxides, 7,000 tons of sulfur dioxides and .5 ton of mercury. The carbon dioxide avoided is the equivalent of taking approximately 309,000 standard-size automobiles off the road each year.

"Our investment in Whispering Willow Wind Farm-East helps us balance the need to provide affordable energy to our customers while at the same time making sure we’re utilizing new technologies to reduce our impact on the environment," said Tom Aller-President, IPL. "We are extremely grateful to the community leaders and residents of the Franklin County for their tremendous support throughout this process.

"We’re also proud and excited that the addition of this wind farm keeps Iowa in a leadership position for megawatts of wind energy installed in the U.S.," said Aller. According to the American Wind Energy Association, Iowa is currently ranked second in wind capacity installed.

Whispering Willow Wind Farm-East consists of 121 wind turbines spread out over 144 square miles in Franklin County, Iowa. Construction on the wind farm began in the fall of 2008. The Iowa Utilities Board (IUB) approved IPL’s request for ratemaking principles pertaining to the construction of up to 200 megawatts of wind power in February 2008. The IUB’s approval included a return on equity of 11.7 percent and a 25 year depreciation life for up to 200 megawatts of IPL wind development. Ratemaking principles are fixed and define how the costs associated with building wind facilities will be recovered in utility rates throughout the life of the project.

Building on its long-term commitment to renewable energy, Alliant Energy’s subsidiary, Wisconsin Power and Light Company (WPL), plans to add an additional 200 megawatts of wind power to its portfolio during 2011 at its Bent Tree Phase I project in Southern Minnesota.

Whispering Willow Wind Farm Facts

* The wind farm spans approximately 92,000 acres or approximately 144 square miles
* More than 400 landowners have signed land options
* The towers are tubular and made of rolled steel. The blades are made of fiberglass–reinforced polyester or wood epoxy.
* Each wind turbine is capable of producing approximately 1.65 megawatts, the equivalent of powering approximately 400 homes
* The concrete foundation support is approximately 50 feet wide by 7 feet deep
*This requires more than 450 cubic yards of concrete, which equals approximately 30 concrete mixing trucks
* Height of the wind turbines is nearly 400 feet from the ground to the tip of the blade when a blade is straight up
* Distance from the ground to the ‘hub’ is approximately 262 feet
* The length of each blade is 131 feet
* Each blade weighs 15,000 pounds
* The nacelle weighs 104,000 pounds
* The hub weighs 42,000 pounds
* The total weight of each turbine including the tower, hub and blades is more than 450,000 pounds.
* Power generation begins at 9 miles per hour with a maximum power generation of 47 miles per hour
* The wind turbines will produce power approximately 90% of the time, depending upon sustainable wind speeds
* When completely developed, the Whispering Willow Wind Farm will employ between 18-25 employees per phase

Whispering Willow Wind Farm

When did IPL purchase the development rights to Whispering Willow wind farm? December 2007

Why was IPL interested in this site? Alliant Energy believes in preparing for our customers’ and Iowa’s energy future. Our company is committed to maintaining our strong renewable presence in the State of Iowa. The Whispering Willow Wind Farm is located in the center of our state’s ‘wind belt’, which means that the wind will generate electricity for our customers more consistently than in other parts of Iowa.

How much electricity will be generated by Whispering Willow Wind Farm? Whispering Willow will generate approximately 200 megawatts of electricity each year, or enough to power approximately 50,000 homes.

How many turbines will there be at Whispering Willow Wind Farm? Whispering Willow Wind Farm Phase 1 will have 121 Vestas V82 turbines.

Where is the wind farm site and where will the turbines go? The wind farm site is located in north central Iowa and spans portions of Franklin County, Iowa.

What type of agreement exists between the landowners and IPL? Landowners who are willing to host a wind turbine signed agreements providing a long-term, stable source of income for property owners. This is also a finanicially viable project for IPL.

What type of turbine is used at Whispering Willow Wind Farm? Vestas V82 wind turbines will be used at Whispering Willow Wind Farm. Each of the turbines is capable of producing 1.65 megawatts of electricity.

How often will IPL employees be present at Whispering Willow Wind Farm? Approximately 18-25 full-time staff will be required for the operation of the Whispering Willow Wind Farm. These employees will be a combination of management, engineering, technicians and administrative staff.

What type of lighting will need to be around the wind turbines? There will be no base-level lighting on or around the wind turbines. The only lighting on the wind turbines will be mandatory FAA lighting on the top of the wind turbine to alert aircraft.

Will the wind turbines produce noise? Wind turbines only produce measurable noise when they are operating, but it is not disruptive to most people in most situations. Today, an operating wind farm at a distance of 750 to 1000 feet is no noisier than a modern kitchen refrigerator. You can stand directly beneath a turbine and have a normal conversation without raising your voice.

Will the landowners still be able to use the land around the wind turbines? With the exception of a 50’ x 50’ parcel directly surrounding the wind turbine’s base and a narrow access road, landowners will be able to utilize all the land surrounding the wind turbine. Many farm roads can double as access roads, reducing non-usable land even further.

Costs and Economic Impacts

What will Whispering Willow cost? Phase 1 will cost approximately $400 million.

Will Whispering Willow Wind Farm help the economy in Franklin County? “Shared revenue” payments are made each year to the city, village, or township and the county in which the facility is located.

There are also anticipated increased revenues to local businesses (hotels, restaurants, gas stations) during the construction phase of the project.


What are the environmental benefits of wind power? Wind power benefits the environment because it does not create any emissions or deplete natural resources, such as wetlands and animal habitats.

How will Whispering Willow Wind Farm benefit Iowa’s environment? By offsetting the need for traditional fossil fuel generation, Whispering Willow Wind Farm will help Iowa’s environment. When completely developed, Whispering Willow Wind Farm will reduce IPL’s system-wide annual emissions:
* Sulfur dioxide (S02 )reduced by approximately 7,000 tons
* Nitrogen Oxide (NOx) reduced by approximately 2,600 tons
* Mercury (Hg) reduced by approximately 0.5 tons
* Carbon Dioxide (CO2) reduced by approximately 2,000,000 tons, which is equivalent to:
* Removing 309,000 cars from the road for one year
*Accumulating electric energy savings equal to powering 232,000 homes for one year
*Saving 206,000,000 gallons of gasoline for one year

Will Whispering Willow Wind Farm harm birds or bats? The impact of wind farms on birds or bats is mostly determined by flight patterns of birds and bats in the area and a review of natural resources which could serve as habitats for avian wildlife. In order to determine any potential impacts to birds and bats, a risk analysis was completed during the early project planning stages and a preconstruction bird survey was conducted in the fall of 2008. It was determined the project site is a low-risk for bird and bat mortality.

What additional environmental assessments have been conducted for the Whispering Willow Wind Farm? An analysis of impacts to threatened and endangered species was conducted at the wind farm site. This review concluded that minimal or no impacts to any threatened and endangered species will occur since most land in the project area is already being used for intense row crop production and there is a lack of suitable habitat.

Also, further environmental studies indicate that the wind turbines should not impede upon the natural habitat of other animals, such as deer, rabbits, and should not disturb wetlands areas or historic archaeological sites.

Whispering Willow Wind Farm Project Timeline

When will the wind farm be built? Construction of Whispering Willow began in December 2008 and it is expected to be operational by late 2009 or early 2010.

Alliant Energy is an energy-services provider with subsidiaries serving approximately 1 million electric and over 400,000 natural gas customers. Providing its customers in the Midwest with regulated electric and natural gas service is the company’s primary focus. Interstate Power and Light Company, headquartered in Cedar Rapids, Iowa, is the company’s Iowa and Minnesota utility subsidiary and serves approximately 530,000 electric and 235,000 natural gas customers. Alliant Energy is a Fortune 1000 company traded on the New York Stock Exchange under the symbol LNT.