Neighbor Frederica Merrell recently sent a letter of complaint about the power lines to Seattle City Light Superintendent Jorge Carrasco, asking, among other things, “why didn’t they bring the power in from below and run the lines through the tunnel, putting them under the freeway instead of draping them in the open where they will face wind and weather?” and received the following response:
Thank you for your note about the electrical service upgrade in Beacon Hill.
Seattle City Light installed an additional set of power lines to provide service for Sound Transit’s light rail trains, electrified buses and growing energy needs in the Rainier valley. The utility spent about three years reviewing possible routes and designs to deliver this needed service upgrade. While we try to limit the impact of such projects on the surrounding neighborhoods, safety for residents and our workers, reliability of the electric supply, and cost are important considerations as well.
On this project, adding additional power lines required poles that could handle more weight and stand up to more wind than the poles that had been used before. Working with Sound Transit, City Light determined that the middle of the hillside could not support such a pole. Additionally, the original pole had been located in an area that had no road access. Any maintenance work required crews to hike the hill, carrying any tools and supplies to the site. Such circumstances increase the risk of injury to our workers and make it more difficult to complete repairs. Without the ability to place a mid-hill pole, the poles at the top and bottom of the hill needed to be taller in order to maintain the minimum wire clearance necessary for safety.
Our engineers considered running the lines through the bus tunnel. That option was determined to be unworkable. City Light crews would have limited access to the tunnel for maintenance and repairs. City Light’s alternating current power lines also would have been located near Sound Transit’s direct current lines, creating a safety issue for any maintenance work. Finally, this approach would have added more than $1 million to the cost of the project.
Our engineeers also considered placing these lines underground. To do so would have required directional drilling or boring small tunnels (microtunneling) down the slope. A soil engineering study found a significant risk that such tunnels could collapse during the boring. Even if such an effort was successful, it would have added at least $1 million to the project for directional drilling and $5 million or more for microtunneling.
City Light and Sound Transit recognize that the community notification about this project and its impact on Beacon Hill residents could have been better. We have taken steps to improve our processes for identifying potential neighborhood impacts of the work we do and sharing information with community members earlier in the process. We would welcome the opportunity to meet with you and your neighbors to discuss this project further.