Project update: January 2017
Tacoma Power and the City of Tacoma are still planning improvement projects on North 21st Street. But, to move forward on replacing the aging lattice towers and lines, some key decisions related to road design still need to be finalized. As a result, the towers will not be replaced in 2017 as planned.
The original schedule called for Tacoma Power to take down the existing lattice towers and replace them with fewer steel poles this spring. Those changes would allow the City of Tacoma to take advantage of the new open space in the street to add things like turn lanes, sidewalks and bicycle lanes once that project gets funded. (For more information on the traffic improvements, please visit the City of Tacoma's website. )
After the City determines its preferred street design option and the turn lane dimensions, Tacoma Power will know where to place the new power poles and when it can move forward. Construction could begin in the spring of 2018, pending the City’s street design progress.
Existing Tower On N. 21st Street In Tacoma
What’s included in the tower replacement project?
Tacoma Power is planning to replace the 19 aging lattice towers on and near North 21st Street with 12 steel monopoles on every other block. As part of the project, Cushman Substation will be disconnected from the electrical system.
What will happen to the old power towers in the median of N. 21st Street in Tacoma?
Tacoma Power will tear down the bulky, rusty lattice towers on the otherwise picturesque 1.25 miles between North Highland and North Adams and replace them with sleek, galvanized steel poles.
Why do the towers need to come down?
The lattice towers are over 90 years old and in a state of significant deterioration.
How many towers are there now, and how many will there be when the project is complete?
There are now 19 total towers: one on every block of North 21st from North Adams to North Highland (total of 15); two in nearby Westgate Center; one near Cushman Substation; and one in front of Pearl Substation on Pearl Street. Those towers are about 75 feet tall.
They will be replaced with 12 galvanized steel monopole towers: one every other block of North 21st Street (total of nine); two in Westgate Center; and one at Pearl Substation. The new towers range from 100 to 110 feet tall.
In addition, some of the wooden poles that line the sides of 21st Street from Puget Sound Avenue to Proctor will be replaced with taller wood poles.
Are there other components to the project?
Yes. The tower replacement is part of the Pearl/Cushman Upgrade project, which includes improvement to how the circuit breakers will work for the transmission lines that connect three large substations throughout Tacoma (Pearl, Cedar and Hilltop substations).
What will happen to the Cushman Substation?
In the fall of 2016, some of the substation’s features were turned off, but it’s still an energized substation. In the fall of 2018, it will be disconnected from the electrical system and no longer an energized substation.
How will the recent nomination of some of the Cushman property to the Tacoma Register of Historic Places affect the project?
That has not yet been determined. The nomination requests that:
- One of the old lattice towers (at North Adams and North 21st Street) remain standing
- The equipment, steel structures and foundations within the Cushman and Adams substation fences remain in place (even if not in use)
- Cushman and Adams substations be added to the register, with protections for both the exterior and interior of Cushman
Tacoma Power is awaiting a recommendation by the City of Tacoma’s Landmarks Preservation Commission to the City Council on the nomination, which includes structures that Tacoma Power had planned to remove as part of the pole replacement project. The historic nomination issues will be discussed, and public comment taken, at the upcoming Landmarks Preservation Commission hearing at 5:30 p.m. on Feb. 8 in the Tacoma Municipal Building, 747 Market St., Room 248.
New Poles Will Be Similar To This
What is the history of the towers?
The towers are part of the Potlatch Transmission Line, which was originally built in 1925 to bring power from the Cushman Hydroelectric Project to Tacoma. Other than a few structures at the hydroelectric project, the lines on North 21st will be among the last of the original transmission line structures to be replaced. Tacoma Power replaced the Narrows lines in 2006 and North Bay lines in 2014; the Henderson Bay towers at Purdy will be replaced in 2018.
What is the project schedule?
- Design and permitting: Ongoing through 2017.
- Cushman Substation: The substation was deactivated in the fall of 2016, which means some of its automated functionality was turned off. It is still an energized, functioning component of the utility’s power system. The equipment and structures within Cushman Substation fence will be removed at the end of 2018.
- Construction on North 21st Street is targeted to start during the spring of 2018, pending the City’s street design progress.
- The project would be complete by the end of 2018.
What is the project cost?
The estimated project cost is $8 million.
Why are the lines going overhead instead of underground?
Transmission lines are not typically placed underground because of the significant increase in cost. In this case, the cost would be five to 10 times more than overhead lines.
For more information, contact Nora Doyle at (253) 502-8117 or email@example.com.