A proposal for a new transmission line from the Madison area south into central Illinois is included in a state energy planning document recently released by the Public Service Commission.
The Strategic Energy Assessment, which outlines Wisconsin's current energy picture and its needs through 2018, includes a proposal for a $184.5 million, 345-kilovolt transmission line from Middleton to Lee County, Ill.
According to the utilities seeking to build the line, in their own, separate documents, the line would run 218 miles, well past Lee County into central Illinois, and would cost an estimated $444 million.
If approved, it would be the fourth major electricity highway to be built in and around the Madison area. Here are the others:
• The 32-mile, $219 million Rockdale-West Middleton line across Dane County, from Christiana to Middleton is nearly complete, scheduled to go into service in 2013.
• The proposed Badger Coulee line from the La Crosse area to the Madison area is down to two favored routes and is expected to be submitted to state regulators for consideration in the first half of 2013. It would run 150 to 170 miles and would cost up to $500 million.
• A possible high-voltage line from Middleton to Dubuque, Iowa, also is in the assessment.
The most recent proposal for the Wisconsin-Illinois route, recommended to be in service by the end of 2021, is one of seven projects suggested in late 2011 by DATC, a joint venture formed by Duke Energy, of Charlotte, N.C., and American Transmission Co., Pewaukee.
The seven represent "gaps in the transmission grid across the Midwest," said DATC spokeswoman Anne Spaltholz. She said the projects would also improve reliability of the electrical system, provide economic benefits to local utilities and make it easier to move power created by renewable resources.
Planning engineers are still analyzing the potential need and benefits of the lines, Spaltholz said, and there are no immediate plans to move forward with them.
The Sierra Club's statewide office is not taking a stand on new transmission lines at this time. "While the Sierra Club would support carefully routed transmission lines needed for bringing renewable energy online, given the huge costs for ratepayers and local habitat impacts, new lines must be scrutinized to ensure that we don't extend the lifespan of aging coal plants," chapter director Shahla Werner said.
On other matters, the Strategic Energy Assessment estimated the overall need for electricity in Wisconsin to grow between 0.3 percent and 1.7 percent a year through 2018. However, a chart projecting peak power demand — on the hottest days when the largest amount of electricity is needed — indicates that based on average summer temperatures, Wisconsin consumers won't return to the 2011 or 2012 power use peaks until sometime after 2018.