Underground Electric Transmission Installations Gaining Traction

By Jeff Griffin, Senior Editor | June 2010 Vol. 65 No. 6
Two jack and bore underground duct installations for Progress Energy in St Petersburg, Fla. Photo: Brierley Associates

Manholes or vaults must be constructed along the cable route. Each section of cable is pulled into and out of vaults where connections are made and future maintenance will be performed.

“Civil construction costs -- excavation, duct banks, restoration -- often are 50 percent or more of project costs,” says Burks. “And from a contractor’s perspective, most of the risk of a project is on the civil side.”

Southwire 230 kV XLPE cable (Photo courtesy of Southwire)

Burks adds that because underground transmission work is highly specialized, only a few contractors are qualified for the work.

“However,” he adds, “the landscape of contractors is changing. Cable improvements are reducing the degree of specialization required.”

In conclusion, Dorwart believes the public and government will be demanding more underground transmission to create a backbone grid that will be hardened to acts of God and terrorists threats; to provide reliable power delivery to lifeline service nodes; and to improve quality of life by removing unsightly overhead transmission systems, especially for new “green” energy production facilities.

“Based on this public pressure,” he concludes, “I believe that the outlook for underground power transmission construction will be strong in urban areas and in areas of alternative energy production for connection to the grid.”

Brian Dorwart has extensive experience designing trenchless projects that include underground transmission segments, and he currently is designing shore landings for cable runs crossing the Hudson River between New Jersey and New York, and directional drilling river crossings for power transmission installations in Jacksonville, Fla., and Malden, Mass.

Black & Veatch is a leading global engineering, consulting and construction company specializing in infrastructure development in energy, water, telecommunications, management consulting, federal and environmental Black & Veatch has completed several landmark underground power transmission projects.

Quanta Services provides a full range of services for the electric power, natural gas, pipeline, telecommunications and cable television industries, including designing, installing, repairing and maintaining network infrastructure nationwide. Quanta company EHV Power specializes in underground power transmission.

Southwire is a leading manufacturer of wire and cable used for transmission and distribution of electricity for commercial, residential, industrial, institutional and OEM applications.