MADISON, Wis. -- After a year and a half, the state's Public Service Commission has approved a route for the highly debated American Transmission Co. through Dane County.

The three-member commission on Thursday unanimously supported the building of the high-voltage line through Madison, along the Beltline and above ground with 120-foot poles.

The decision is a big victory for farmers and rural residents who were fighting proposed routes that would have disturbed farms and landscapes.

But it's a big loss for Madison and others who wanted the line to be built underground, which would cost more.

The Public Service Commission was considering four proposed routes and said Thursday that the Beltline plan is best for everyone.

"I cannot justify creating a new corridor and moving the line to a rural landscape in order to protect the aesthetics of an already heavily commercialized corridor," said Public Service Commissioner Mark Meyer.

"In this case, the only reason for undergrounding it would be to avoid the aesthetic impact of the project on the Beltline. I do not believe the risks and additional costs warrant this step," said Commission Chair Eric Castillo.

The Public Service Commission rejected three other mostly rural routes for the 345-kilovolt line from west Middleton to Rockdale and instead it went with the shortest, cheapest route -- right down the middle of Madison.

The commission found no bias in the power line plan toward any particular type of neighborhood and flatly rejected plans backed by Madison and others to bury the line.

"The fact is this route simply follows a major highway, which takes it through a variety of neighborhoods, some of which are of lower economic means and some of higher economic means," said Commissioner Lauren Azar.

But the Public Service Commission did try to ease some specific concerns.

Shorter 80- to 90-foot poles configured horizontally will be put in along the arboretum, so the visitors' center and other overlooks aren't marred. And along Odana Gold Course, taller poles will be arranged differently so fewer trees will get cut down.

The commissioners on Thursday said they agreed with ATC's experts that the line was needed to meet need and avoid blackouts by 2015 or sooner.

They also said dips in demand won't last and energy efficiency and conservation can't replace the growth in demand.

Construction will start in two years and finish in 2013.