Marine

Redirecting Power around San Francisco

Durocher Marine installed three, 230 kV power transmission and fiber optic cables between two major substations.

Inside the Project

Sumitomo Electric subcontracted the subaqueous installation of the three 240kV transmission and fiber optic cables between the Potrero and Embarcadero Substations in downtown San Francisco. Prior to our arrival the owner installed three HDPE conduits at each substation. The conduits extend out from the harbor into 35 feet – 85 feet of water and were 1,000 feet and 1200 feet long. Ships from Japan delivered the three cables in individual tubs to the Port in San Francisco. Each tub weighed approximately 320 tons. After mobilizing our lay barge a single tub was set onto our 1,000-ton portable turntable. The lay barge moved into position and pulled the first power and fiber cable to the Potrero substation via the conduits. After the cable was secure the lay barge simultaneously laid and buried the 5-13/16-inch power cable and fiber optic cable with our water jet plow. Each lay route was a distance of 12,700 feet to the second conduit. At the second conduit the lay barge stopped, floated 2,100 feet of cable in a tidal zone, and winched the cables up the conduit to the Embarcadero Substation. The process was repeated two more times.

Why it matters

Downtown San Francisco is a very busy and highly developed area. The owner investigated three options for the 240kV installation. Two of the options were through the city streets of San Francisco. Each of these routes crossed the I-280 corridor and other sensitive areas. These options were not economically viable. Moving the lay route out into the bay circumvented most of the logistical problems associated with navigating this construction through the city.

For a deeper look into the project, read the latest story in Transmission and Distribution World.