Iowa: wind farms among the farms

Mon, 10/12/2009 - 4:30am

10/10/09 - On a recent trip to Iowa to visit relatives, we looked more closely at what we once called monotonous prairie. With this year’s bumper crops almost ready for harvest, Iowa’s amber fields were reminiscent of a vast rolling sea. Waves of soybean plants and corn stalks swayed gracefully in the wind as far as we could see across the gently rolling land.

Amber waves of grain are not the only graceful stalks swinging in the wind there. Iowa is home to wind power. It has both large and small installations. We discovered that Iowa is ahead of the East Coast when it comes to renewable energy.

We passed the Top of Iowa Wind Farm on our way south from the St. Paul-Minneapolis airport along Interstate 35, and a second vast wind farm farther south in central Iowa. From the home of our relatives in Algona, Iowa, we could see three turbines that provide renewable energy to that area’s local municipal power companies.

Top of Iowa has a total of 89 turbines. Each produces 900 kilowatts and they power a total of 40,000 homes. The height from base to hub is 235 feet, and the total to the tip of the rotor blade is 325 feet.

The total land involved in the project is 10 square miles and the towers are set on 5,500 acres of corn and soybean cropland. The project cost $80 million to construct.

The site was selected because of the strength of the wind there, and the close proximity to Midwestern cities like Chicago, Milwaukee, and Madison, Wisconsin. The project’s fact sheet cites the short distance from the project site to high-voltage transmission lines; expansion possibilities and strong community support. The project sells all of the electricity under a long-term Power Purchase Agreement with Alliant Energy of Madison, Wisconsin.

As we drove by, the turbines reminded me of a troop of dancers, their slender stalks like a dancer’s muscled body, their blades like a Russian ballerina’s arms. So much more graceful than the clumsy cell towers and telephone poles we have come to accept everywhere.

The smaller turbine project in Algona was built in l997. At that time, the three turbines there were the largest manufactured in the United States. They are mounted on 165-foot towers, and are capable of producing 2,250 kilowatts each. Wind at the site averages 16.5 mph, and a minimum of 9 mph is needed to power them.

I was able to park in the roadside in front of them, where they produced a low whirr whirr sound. The wind that day was unusually high for the area, according to my cousin. We walked away from turbines to gauge how far the sound carried. Half a block away, it was gone.

The Algona venture was a joint effort of several municipalities, and is a supplement to Algona’s other power sources. The company’s website states that since 1979, Algona’s primary source of electricity comes from Neal 4, a low sulfur coal-fired electric generation plant located south of Sioux City, Iowa. However, a newer renewable energy project is underway as a joint project of 130 power companies in Iowa and surrounding states.

The Iowa Stored Energy Park will use Iowa’s wind energy “to compress and store air in an underground geologic structure of porous rock. This rock structure, now filled with water, called an “aquifer,” is located 3,000 feet underground, beneath layers of impermeable rock cap. The air will be injected under pressure, pushing back the water. The rock will hold air much like a sponge holds water. Then, as demand for electricity rises, the stored air will be released, heated and used to drive generators.

Another interesting fact about Algona Municipal Utilities is that it is a municipally owned company that supplies not only electric power to the town, but water, sewer, telephone, cell phone, and cable television. It began with water in 1889 and electricity in 1898.

Since June 2009 there was an increase in residential rates of 7.65 cents a kWh with an $8-per month customer charge. The rate schedule includes a number of other categories, which are charged different rates: small commercial, large commercial, industrial, public street lighting, public authorities, school lighting and fairgrounds.

Iowa, which some in the East think of as dowdy farm country, is powering ahead of the east in building and researching renewable and cost effective energy. It is supplying America with a lot more than soy beans and corn. Its progressive power gives us much food for thought.