A high-voltage transmission-line project first proposed in the early 1990s is once again moving forward, this time propelled by a Missouri company.

Idaho Power Co. first acquired the rights-of-way for the Southwest Intertie Project about 15 years ago, and the U.S. Bureau of Land Management performed an environmental study of its route at the time. But the project was shelved until 2005, when Great Basin Transmission LLC - an affiliate of LS Power Development - picked up the rights from the Idaho utility.

Now, the project is on the edge of becoming reality. The 500-kilovolt line would run more than 500 miles from the Midpoint Substation - near Shoshone - to Las Vegas. Construction could start on its southern half this year, and the segment that includes Idaho could be operational by 2011.

Great Basin is gathering bids for space on the future lines and arranging funding to begin work on the project. But the company said Thursday that it may start construction before completing the bid negotiations through a partnership with Western Area Power Administration and funding from this spring's economic stimulus act.

The project would be Nevada's first major north-south power transmission line and primarily would handle energy from new renewable-energy projects, said Mark Milburn, assistant vice president of LS Power and the Intertie's project manager. But it will also provide additional reliable transmission infrastructure for the West, he said, as well as construction jobs and tax revenues for local government.

"We equate more transmission to more supply to better electricity costs," he said.

The Intertie would also link to another proposed transmission project - Gateway West, expected to stretch 1,150 miles across southern Idaho and Wyoming. The Nevada project would essentially provide the Gateway segment from the Midpoint station south to a proposed station in Twin Falls County called Cedar Hill, Milburn said - though Idaho Power may decide another line is needed in the same area. A separate Great Basin project would also connect the Shoshone power station to wind farms in Wyoming, following Gateway's northern route.

Unlike Gateway West, the Intertie's route was largely secured in the 1990s. But Magic Valley residents back then had many of the same concerns they now voice about high-voltage lines, including whether they had any effect on human health.

Great Basin technically has the rights-of-way it needs to proceed, but is still working with landowners to tweak the established route, Milburn said. Among the changes will likely be a detour around the Minidoka National Historic Site.

Wendy Janssen, the site's National Park Service superintendent, said she met twice this spring with developers and was told they are looking for alternate routes through the area. She's concerned not only about the effects of the lines within the site's boundaries, but also just outside of that area where many historic structures and cultural resources still exist. At the same time, she also wants to work with the farmers who live next to the site.

Though Janssen said the 1994 BLM study is now "outdated," Milburn said his company doesn't expect another to be needed. He's very interested in working with NPS and others to address remaining route concerns, he said.

"We're going to be neighbors there for a long time," Milburn said. "We want to participate in the preservation of the site."

Nate Poppino may be reached at npoppino@magicvalley.com or 735-3237.