Rebuilt BPA transmission line returned to service

The Bonneville Power Administration (BPA) energized the final section of the rebuilt Midway-Benton No. 1 transmission line on June 11, completing the rebuild of the 115-kV, 29-mile, 1940s-vintage facility.

“We were able to substantially complete construction without any major safety accidents,” a BPA spokesperson told TransmissionHub July 10. “Our project and construction teams worked collaboratively with key interest groups to design and construct the project with limited environmental impacts.”

While the agency has spent $16.7m to date on the project, which also included the rebuild of an 11-mile portion of the Benton-Othello No. 1 line, it remains responsible for up to five years of environmental monitoring, the cost of which will become part of the total project cost. Additional contract invoices that are still coming in will also increase the total cost, which is estimated at $17m.

In addition to environmental monitoring, BPA must still complete site clean-up.

“We have a large section of material to be removed from the site, which should be complete by Jan. 31, 2014,” the spokesperson said.

In March, BPA 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 in the summer of 2014, and will phase the rebuild over the course of three years, an Avista spokesperson told TransmissionHub in April. The current cost estimate for its portion of the line is about $3m per year, plus or minus 20%, the spokesperson said.

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

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.