In April, Tacoma Power will begin replacing the towers and power transmission line on North 21st Street with new steel poles and a new transmission line.
What’s included in the tower replacement project?
The utility will replace 19 aging towers on and near North 21st Street with 12 steel poles on every other block. As part of the project, the utility will disconnect the Cushman Substation from the electrical system during the second half of 2018.
What's the tentative construction schedule?
- Steel poles delivered in January
- Contractor selection in March pending bid results and Public Utility Board approval
- Construction anticipated in spring and summer
- Project completion slated for fall
Why do the towers need to come down?
The more than 90-year-old towers have deteriorated significantly.
How many towers exist now, and how many will exist when the project is complete?
There are 19 towers: one on every block of North 21st from North Adams to North Highland (total of 15); two in nearby Westgate North Shopping Center; one near Cushman Substation, and one in front of Pearl Substation on Pearl Street. Those towers stand about 75 feet tall.
Tacoma Power will replace the towers with 12 steel poles: one on every other block along North 21st Street (total of nine); two in Westgate North Shopping Center; and one adjacent to Pearl Substation. The new towers range from 90 to 120 feet tall.
In addition, eight wood poles that line the north sides of N 21st St from Puget Sound Avenue to N Proctor St will get replaced with taller wood poles (up to 84 feet high). The new wood poles will align new wire with the existing power lines near Cushman Substation. We'll also completely remove eight existing wood poles and install three new ones (up to 84 feet high).
Are there other components to the project?
Yes. Some upgrades affect how the circuit breakers work with the transmission lines connecting three large substations.
Does any prep work have to occur before the towers and wood poles get replaced?
Yes. Before the North 21st Street project begins, some preliminary work must occur:
- A City of Tacoma Public Works Department contractor must replace about 110 feet of sanitary sewer line between N Cheyenne St and N Verde St.
- A Puget Sound Energy contractor must relocate about 50 feet of gas line between N Baltimore St and S Orchard St.
- Century Link must relocate a communications line near N Winifred St.
What will happen to the Cushman Substation?
A separate project is underway to determine the future of the Cushman Substation. We're working with the City Manager’s Office to develop a Memorandum of Understanding about the substation, with the potential to transfer it to General Government in the future.
What is the history of the towers?
Built in 1925, the lattice towers on North 21st Street are part of the Potlatch Transmission Line that brings power from the Cushman Hydroelectric Project to Tacoma.
What will the project cost?
The estimated project cost is $8 million.
Why will Tacoma Power place the lines overhead instead of underground?
The utility doesn't typically place transmission lines underground because of the significant increase in cost. In this case, underground lines would cost five to 10 times more than overhead lines.