American Transmission Co. is modifying its filing date to the Public Service Commission of Wisconsin by at least three months for the Rockdale-West Middleton 345-kV transmission line project. Originally, ATC planned to file its construction application with the PSC in June, but will now target October 2007.

“We are being responsive and responsible to the people of Dane County,” said Mark Williamson, vice president of major projects. “We have a critical need here, but taking some additional time to address concerns and issues is a reasonable and prudent compromise.”

ATC unveiled three general route options last summer for connecting the Rockdale and West Middleton electric substations in Dane County and expected to be ready to announce the final routes this month. “During the past year, residents, stakeholders and elected officials have actively engaged in the process, made recommendations to us, and asked appropriate questions,” said Williamson. “Among them is the feasibility of placing high-voltage transmission lines underground along portions of the routes.”

In addition to undergrounding, questions about electric usage forecasts, environmental impacts and the recent Department of Transportation concerns about the Beltline route have added work to the preparation of the company’s application to the PSC. Williamson reiterated the crucial need for this project. “We’re eager to get this project in the hands of the regulators, but we want to fully explore these issues without compromising our ability to keep the lights on. Today, we’re looking at an in-service date in 2013, rather than in 2012.”

According to Williamson, the preliminary evaluation of underground construction suggests that it is not a feasible option for the 345,000-V project. “The significant added cost is only one factor. We continue to have serious concerns about the construction, reliability and environmental impact of placing power lines of this voltage underground,” he explained. “However, we’ve agreed to perform a more comprehensive analysis and develop detailed underground transmission line options for project at the request of the PSC and the public. This analysis will be included in our application to the PSC.”

Dane County is one of the fastest growing counties in Wisconsin and few significant improvements have been made to the transmission infrastructure in nearly 30 years. The county is mainly served by a network of 69- and 138-kV transmission lines. The expected growth in the coming years cannot be served by the existing system. A new 345-kV line will allow power to flow in from other areas to efficiently serve Dane County and boost the reliability of the entire network.

The regulatory review process, which will begin after the PSC receives ATC’s application this fall, will likely continue through most of 2008—during which time the public will have an opportunity to participate in public hearings on the project.