Jun 29 - McClatchy-Tribune Business News Formerly Knight Ridder/Tribune Business News - Scott Miller The Pantagraph, Bloomington, Ill.

Construction of the Twin Groves Wind Farm in eastern McLean County begins Thursday, quashing any concerns about national security risks or wetland conservation.

Developer Horizon Wind Energy has received all permits and will start excavating land, developing access roads and staking out sites for the turbines Thursday, said Bill Whitlock, project developer.

"You won't see any (turbines, blades or towers) for at least four to six weeks," he said. "Specialized crews will kind of follow each other through the project. It works in piece meals."

Work starts about a 1.5 miles north of Ellsworth on County Highway 17, Whitlock said. The wind farm is located just south of Illinois 9 near Arrowsmith, Ellsworth and Saybrook.

In a move some called politically motivated, Twin Groves and other Midwestern wind farms faced congressional concerns that the massive turbines could interfere with military radar and pose a national security risk. The Federal Aviation Administration is looking into the matter, effectively halting construction of several other wind farms. Twin Groves already cleared that hurdle, however, said Michael Skelley, chief development officer for Horizon.

Meanwhile, the U.S. Army Corps of Engineers studied the impact Twin Groves would have on wetlands. That archaeological study has concluded, giving Horizon the last federal permit needed for construction.

Twin Groves should be partially operational by the end of the year, Whitlock said.

The $500 million wind farm includes up to 267 turbines on 21,000 acres of land. It will generate about 400 megawatts of energy, enough to power about 120,000 homes.

The energy will become part of the Commonwealth Edison grid, which serves the Chicago area, Whitlock said.

The company also plans a wind farm at Blackstone in northern Livingston County, according to Horizon's Web site. Construction there is projected to start in spring 2008 and conclude that December.

East of Interstate 39 is the Mendota Hills Wind Farm where 63 wind turbines generate power for Commonwealth Edison. Construction is set to begin Thursday on the Twin Groves Wind Farm in eastern McLean County.