How Seattle City Light relocated a transmission line with international implications

Last fall, Seattle City Light and its partners took on the monumental task of relocating nearly half a mile of 115kV transmission line along Seattle’s waterfront.

While relocating a transmission line is nothing new to City Light, the potential impacts of this line were more challenging than others.

This specific line is a vital part of the Bonneville Power Administration’s ability to power the country’s western half, extending from Canada down to Arizona.

The project took detailed planning and coordination, but City Light was up to the task.

The team preparing to pull the spools of 115 kV line

This work was necessary to construct the elevated roadway at Elliott Way west of the Pike Place Market. Planning for the project began in 2013, dating back to the construction of the SR 99 Tunnel, the demolition of the Alaskan Way Viaduct and the reimagining of the waterfront. Because of its importance to the western energy grid, it is only taken offline twice a year.

City Light Senior Project Manager Mike Fernandes, who took over the project in 2019, led a team at City Light to coordinate with multiple local, state and federal agencies and contractors to execute this relocation project. Their deadline: October 31, 2021.

Procuring a 115kV line isn’t as simple as picking it up from a warehouse. It had to be ordered at least a year in advance and was ordered from the firm UTEC located on the East Coast. The team that installed the transmission line also specialized in this type of project and worked closely with the operators of the utility’s substations in Seattle’s downtown core along with City Light’s safety managers to ensure all those involved were informed and ready for the day of installation. For Mike and his team, there was minimal room for error.

“We had a narrow window for the transmission line to be offline,” Mike explained. “Missing our window would have delayed the construction of the waterfront for six months, so we prepared for as many variables as we could think of. We had multiple pre-construction meetings to make sure everyone knew their role when it was go time.”

Crews working on the 115kV transmission line

Finally, the line arrived on large spools, and it was time to get to work. The team relocated the 2,200 feet of transmission line successfully and seamlessly within their limited window of time. Now, the construction of Seattle’s new waterfront could continue without delay.

“We are proud of the coordination and the hard work of all of the teams involved with this project,” Mike said. “It’s a great example of the attention to detail our employees take to complete their work as efficiently and, most importantly, as safely as possible.”

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