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Thumb Loop moves ahead; High-voltage line connects wind farms

Like soldiers standing rigidly to attention, a line of power poles marches through the corn and soybean fields of Greenwood, Kenockee and Wales townships.

Crews were busy the past week stringing conductors – wires – along transmission towers as part of Phase 2 construction of the $510 million Thumb Loop high-voltage transmission line project.

The project, said Gregory Ioanidis, will connect the wind farms of the Thumb with the electric transmission grid. Ioanidis is president of ITC Michigan, the company building the transmission line.

“If you were to draw the project on a map of Michigan you would see it circling the Thumb and around,” he said.

The first phase of the project, 62 miles of double circuit, 345,000-volt lines from a susbstation called Bauer near Vassar in Tuscola County to a second substation near Rapson, an unincorporated community in Huron County, is in service, Ioanidis said.

“We’re now on Phase 2, which is primarily in St. Clair County,” he said. “It goes from a station of ours called Greenwood. That segment is about 20 miles. All of our foundations are in, our poles are erected – we’re at the stage now where we’re starting to string conductors.”

The segment runs from Greenwood to a new substation being built at Fitz and Marlette roads in Wales Township.

“In Phase II they are going to see 86 towers on this 20-mile segment,” Ioanidis said. “Eighty of them are going to be steel monopoles and six the traditional lattice towers.”

Ioanidis said the Clean, Renewable and Efficient Energy Act passed by the state Legislature in 2008 requires that some portion of a utility’s power generation be from renewable resources. The Thumb was identified as the region in the state with the greatest potential for power generation using wind turbines.

“What this project helps do is serve as a backbone for this entire Thumb region to interconnect these wind resources,” he said.

ITC, which operates and maintains more than 8,200 miles of high-voltage electric lines and 236 transmission stations in the Lower Peninsula, was tasked with creating a transmission plan that would accommodate a minimum of 2,300 megawatts and a maximum of 4,200 megawatts, Ioanidis said.

He said a very large nuclear power plant generates 1,100 megawatts. One megawatt is 1 million watts.

“A typical wind farm, when they erect all their turbines, some of the numbers we’re seeing are150 megawatts,” Ioanidis said.

He said ITC has about 733 megawatts connected to its system, with another 559 megawatts under construction.

“In addition to being able to integrate the wind systems, the project helps support transmission reliability in the Thumb,” Ioanidis said.

The project will have a third phase, beginning in the first quarter of 2014, from Rapson in Huron County through Sanilac County to Greenwood in St. Clair County, Ioanidis said.

The project is to be completed and in service by 2015.



• Total miles of wire: 3,640
• Number of steel monopoles: 786
• Number of steel lattice towers: 30
• Distance between poles: 800 to 1,100 feet
• Average number of poles per mile: 6
• Height of poles: 130 to 180 feet
Source: ITC Transmission