Wind-PowerIowa’s largest utility is in the process of installing its tallest wind turbine in southwest Iowa from a new type of material. When finished, it will be the tallest land-based wind turbine ever built in the country.

MidAmerican Energy spokeperson Ruth Comer says the company’s first concrete wind turbine tower is under construction in Adams County.

“All of our other wind turbines use a steel tower construction,” Comer says. “With the concrete tower, we’re able to build a taller wind turbine and take advantage of increased winds that are generally found at higher altitudes.”

The process of building the concrete tower will be different from traditional steel towers. Instead of building the tower sections in a factory and trucking them to the site to be fitted together, crews pour the concrete in segments and manufacture the tower onsite. The new tower will rise over all others.

“This concrete turbine tower at the Adams Wind Farm will be 377 feet from the ground to the hub, where the blades attach,” Comer says. “That compares to 263 feet for most of our other wind turbines, so it’s a little more than a hundred feet taller than the turbines we have at our other wind farms.” With the blades extended, the turbine will reach a height of 554 feet, making it about as tall as the Washington Monument.

Des Moines-based MidAmerican is contracting with Siemens Americas Onshore Wind for that company’s first concrete tower project in North America. “We worked on a lot of wind farm projects with Siemens and both Siemens and MidAmerican Energy are looking at this concrete turbine tower as a prototype,” Comer says. “We’ll see if it does indeed capture more wind from higher altitudes. If it does, we’ll look at it for future wind farms.” The concrete turbine is one of 64 turbines planned for the Adams County wind farm.

Construction should be complete on the 154-megawatt project by the end of this year. MidAmerican Energy provides electric service to 746,000 customers and natural gas service to 726,000 customers in Iowa, Illinois, Nebraska and South Dakota.