A crane atop a barge anchored off Sunset Boulevard in the Santa Monica Bay is generating a lot questions from Topanga residents.
It’s not part of an oil exploration project, or a commercial fishing operation. Instead, the vessel is part of a major project to replace a key piece of Los Angeles electrical infrastructure, the underwater portion of the Sylmar Ground Return System, part of a larger power network known as Pacific Direct Current Inter-tie, or Path 65.
This system transmits hydroelectric energy from the Pacific Northwest to Los Angeles using high-voltage direct current. It includes 31 miles of overhead lines, underground cables, and underwater cable segments that begin in Sylmar and end in the Santa Monica Bay, off the coast from Gladstone’s Restaurant
According to the Los Angeles Department of Water and Power (LADWP), the replacement project is needed because the original system, installed nearly 50 years ago, has some major problems, including seawater penetration, corrosion of the marine cables, and metal fatigue.
The new ground return system will extend two miles offshore, where the cables will connect to an electrode array that provides a “ground point,” a sort of lightning rod that directs the electricity carried by the cables back into the earth. During an emergency such as a major earthquake, this ground return would ensure that power could be safely discharged without damaging the electrical grid.
The replacement project is lengthy and complex. It includes laying new cable that will be buried several feet under the sea floor, and installing 36 pre-fabricated concrete vaults in 100 feet of water. In addition to the 30-ton crane that has been at work in the bay for the last couple of weeks, the project requires an array of smaller, but equally specialized vessels, including a cable-layer, an assortment of tug boats, and something described as a seafloor “jet plow,” according to a Coastal Commission staff report on the project.
An LADWP report on the project states: “The project will help to maintain the reliability and stability of the power generation and delivery system for Southern California; continue to meet current and projected demand for power; and increase the available share of renewable resource energy from wind power in the Pacific Northwest.”
The project required an extensive approval process from a host of agencies ranging from the Coastal Commission and State Lands Commission, to the California Department of Fish and Wildlife.