As part of the contract, Siemens is responsible for transportation, installation and commissioning of wind turbines, which feature a113m rotor and 92.5m hub height.

In addition, Siemens signed a three-year service and maintenance agreement for the project.

The installation of the turbines is expected to begin in mid-June 2014, while commercial operation is slated for December 2014.

Siemens will manufacture blades for turbines at its facility in Fort Madison, Iowa and D3 nacelle component will be assembled in Hutchinson, Kansas.

Siemens Energy Wind Power Americas business CEO Mark Albenze said, "The increased MW output also results in a reduction of site infrastructure and operations and maintenance costs."

"We greatly value Minnesota Power’s confidence in our technologies and services and are very pleased to partner with them once again as they continue to provide reliable, affordable and sustainable power to their customers," Albenze added.

Image: Siemens direct drive wind turbine in 3 MW-class. Photo: Courtesy of Siemens Energy.