BPA to energize rebuilt transmission line on Hanford site imminently

The Bonneville Power Administration (BPA) expects to energize approximately 11 miles of the rebuilt Benton-Othello No. 1, 115-kV transmission line located in Benton County, Wash., before April 5, and is continuing rebuild work on the Midway-Benton No. 1 line. Both lines are located on the U.S. Department of Energy’s (DOE) Hanford site.

BPA recently completed rebuilding its portion of the Benton-Othello No. 1 line, which extends northwest from the Benton substation and parallels the Midway-Benton line for 11 miles to the Columbia River. At that point, it crosses the river and continues 26 miles to Avista’s (NYSE:AVA) Othello substation near Othello, Wash. BPA owns and operates the line from the Benton substation to the river crossing, while Avista owns, maintains and operates the line from the Columbia River to its substation.

Avista intends to start rebuilding its portion of the line next summer.

“Our current plan is to begin rebuilding that in the summer of 2014, and we’ll phase it in over the course of three years,” Jeff Schlect, senior manager of FERC policy and transmission services, told TransmissionHub April 1. The current cost estimate for its portion of the line is about $3m per year, plus or minus 20%, he said.

Avista’s portion of the line was originally built in the 1920s, but the utility did significant upgrades in the 1950s and 1960s, an Avista spokesperson said, in addition to completely replacing a short stretch that was destroyed by fire about five years ago.

BPA is also completing the rebuild of the 29-mile-long Midway-Benton No. 1 line. Approximately half the line’s length, 14.5 miles, is being rerouted south of its existing alignment, which will place the line adjacent to a 230-kV transmission line operated by DOE and closer to a paved road allowing improved access for maintenance. BPA is rebuilding the existing H-frame wood pole transmission line with new wood poles, new conductor, and associated hardware.

BPA conducted an environmental assessment under the National Environmental Policy Act (NEPA) and issued a Finding of No Significant Impact (FONSI) in December 2012.

Reconstruction started in the winter of 2012. BPA has approximately 19 miles to complete on the Midway-Benton No. 1 line, which is expected to re-enter service on June 21, a BPA spokesperson told TransmissionHub.

Both BPA’s portion of the Benton-Othello line and the Midway-Benton No. 1 line, which is co-located with BPA’s 230-kV Midway-Benton No. 2 transmission line, are located completely within the boundaries of the Hanford site in eastern Washington.

Total project cost for rebuilding both lines and relocating a portion of the Midway-Benton line is estimated at $17m.

No major work has been done on the transmission lines since they were built in the 1940s. The lines lasted beyond their expected service life, and needed to be replaced, as many of the structures, the conductor, and associated structural components (cross arms, insulators, and dampers) were physically worn and structurally unsound in places, BPA said.