Tacoma Power Uses Cost-Effective Rejuvenation to Manage 4,800 Feet of Submarine Cable
Some 4,800 feet of submarine cable from Tacoma Power, feeding 14 customers on tiny Ketron Island, was nearing the end of its design life. The utility decided to rejuvenate the underwater line before a fault occurred and has not experienced any faults in the now-guaranteed, rejuvenated cable.
The Company and the Situation
Tacoma Power, a division of Tacoma Public Utilities, was created in 1893 when Tacoma, Wash., citizens voted to buy the privately owned Tacoma Light & Water Company. The utility provides electric service to the cities of Tacoma, Fircrest, University Place, Fife, parts of Steilacoom, Lakewood, Ketron Island, and unincorporated Pierce County.
The small Ketron Island community in Washington’s Puget Sound has only 14 year-round residents, but they expect the reliable electric power which Tacoma Power is mandated to provide. Testing of a portion of the 4,800 feet (1,450 meters) of submarine cable feeding the island indicated that the single radial circuit suffered from significant water trees. This finding, along with the age of the cable, indicated reliability should be a growing concern. It was only a matter of time before the first costly underwater repair would be required. The City of Tacoma decided to extend the life of this critical circuit before it failed.
The City had previously received bids to inject this cable, but had not selected a vendor. Novinium submitted a bid that was less than 20 percent of the cost of previous bids and less than 10 percent of the cost of a new cable.