MidAmerican Energy says it’s building the tallest land-based wind turbine in the nation in southern Iowa.
The Des Moines-based power company will get the added height by building the wind turbine tower from concrete instead of steel, a first for the company. The extra 100-plus feet enables the turbine to capture more wind energy, the utility said.
“Generally speaking, the higher the altitude, the greater the wind resource available,” Mike Gehringer, MidAmerican’s vice president of renewable energy.
The 2.3-megawatt concrete tower turbine at the Adams County wind farm will measure 377 feet from ground to hub, compared to 263 feet for most of the turbines in use at other MidAmerican wind farms.
With blades extended, the turbine will reach a height of 554 feet, making it about as tall as the Washington Monument.
The utility has contracted with Siemens to supply and construct its new concrete tower design
Siemens and MidAmerican see the prototype as the model for other concrete turbine towers at future wind farms. It would open up “low-to-medium wind resource areas of Iowa for future wind development,” Gehringer said.
The company said the process of building a concrete tower is quite different from the process used to construct turbines with steel towers. “Instead of building the tower sections in a factory and transporting them to the site to be fitted together, crews pour the concrete in segments and manufacture the tower onsite,” Gehringer said.
The concrete turbine is one of 64 wind turbines planned for MidAmerican’s Adams County wind farm. Construction is underway on the 154-megawatt project, and all turbines are scheduled to be erected by the end of 2015.
Siemens sourced the concrete formwork from EFCO Corp. in Des Moines and supplied the wind turbine blades for the entire Adams project from the Siemens blade factory in Fort Madison.