Wind turbine at the Iowa State Fair.

Iowa’s largest utility is making another big investment in wind power. Des Moines-based MidAmerican Energy is announcing today it will build three new wind farms in five Iowa counties.

 Ann Thelen, spokeswoman for MidAmerican, says the moves will enhance the company’s energy portfolio, adding more than 400 megawatts of power from wind.

“We have signed agreements to acquire (all) of these new wind projects,” Thelen says. “For example, we signed an agreement with Clipper Windpower to acquire about 200 megawatts of wind projects in Audubon and Guthrie counties and also a 101.2 megawatt wind project in Adair County.”

Another agreement is with RPM Access for a 103 megawatt project in Marshall and Tama counties. Combined, 176 new wind turbines will reach into the sky with the projects. There will also be expansion at the existing Rolling Hills project, which covers parts of Adair, Adams and Cass counties.

“When the 2012 wind projects are complete, approximately 29% of our total generation capacity will be powered by wind,” Thelen says. “We are the #1 rate-regulated utility in the United States in terms of wind generation ownership, so that’s pretty exciting for the state of Iowa to be such a leader with an important renewable energy resource.”

She says all of the projects are in the early stages of planning and construction and all of them should be complete before the end of the year. While dollar figures for the latest agreements were not released, Thelen says the utility is making a very significant investment in wind.

Thelen says, “We started building wind projects in 2004, so when we have these 2012 projects complete and we have that approximately 29% of our total capacity from wind, we will have invested approximately four-billion dollars in the state of Iowa for our wind generation projects.”

She says MidAmerican will again be working with Seimens Energy to manufacture the turbines at its facility in Fort Madison. Adair, Adams, Audubon, Cass and Guthrie counties are clustered in southwest Iowa while Marshall and Tama counties are in the east-central region.