San Diego Gas & Electric has announced that it has completed and put into service the Sunrise Powerlink, a 500,000-V transmission line linking San Diego to the Imperial Valley, one of the most renewable-rich regions in California.
The completion of the nearly $1.9 billion project culminates a rigorous, 5-year-long environmental review and permitting process and 18 months of construction that encompassed both overhead and underground technology as well as different climates and rough, remote terrain. The Sunrise Powerlink was the subject of an extensive regulatory review – a collaborative effort involving SDG&E and a number of state and federal agencies – considered to be the most comprehensive study of a proposed transmission power line in state history.
“Putting the Sunrise Powerlink into service is the final milestone in a complex and challenging energy project that ranks among the largest and most significant in the history of San Diego Gas & Electric,” said Jessie J. Knight, Jr., chairman and chief executive officer of SDG&E. “Design, planning, construction and implementation of the project required scores of public hearings, detailed construction schedules to accommodate a wide array of environmental regulations and coordination of thousands of helicopter flights to ferry crews and material to the construction sites along the route.”
Capable of bringing initially up to 800 megawatts of additional imported power into San Diego, the Sunrise Powerlink will play an especially important role this summer, as the line was originally designed to do. The transmission line will eventually carry 1,000 megawatts of power, or enough energy to serve 650,000 homes. SDG&E and the California Independent System Operator Corp. (ISO), the agency that manages most of the statewide grid, consider the Sunrise Powerlink one of the important mitigation measures that will help maintain electric reliability during heat waves without power from the San Onofre Nuclear Generating Station.
“The timing for completion of this important new transmission artery could not come at a more critical time,” said Steve Berberich, president and chief executive officer of the ISO. “Sunrise Powerlink is more valuable today than when it was conceived because of the significant reliability benefits it brings helping to compensate for the loss of power from the San Onofre power plant this summer.”
The Sunrise Powerlink consists of more than 110 miles of overhead 500kV and 230kV transmission towers and conductor, 6.2 miles of underground 230kV cable and a 40-acre, 500kV transmission substation, which reduces the voltage for use by homes and businesses. More than 4.7 million work hours were required to complete the project – the equivalent of 2,260 people working 40 hours per week for a year. Because nearly 75 percent of the tower locations required helicopters to set the tower structures for environmental reasons, it took more than 28,000 flight hours to complete the aerial construction.
“Keeping this project on budget and on schedule by reducing our construction timeline from 24 months to just 18 months is a testament to our employees and all those who worked on this major endeavor,” said Michael R. Niggli, president and chief operating officer of SDG&E. “I am proud of their diligence, dedication and commitment to safety. I also extend my sincere thanks and appreciation to those who live and work in and around the various construction areas for their patience and understanding during this process. ”
In the near future, the Sunrise Powerlink will deliver a significant amount of wind and solar power to San Diego. Over the past three years, SDG&E has signed eight renewable agreements for more than 1,000 MW of solar and wind power from projects in Imperial County; that green energy will be transmitted across the Sunrise Powerlink.
By 2020, 33 percent of SDG&E’s power will be derived from renewable resources. In 2011, more than 20 percent of SDG&E’s electricity was obtained from renewable energy.
“This vital infrastructure project and the construction jobs that were created as a result have revitalized the Imperial Valley region, which has experienced high unemployment for years,” said Imperial County Board of Supervisor Gary Wyatt. “The Sunrise Powerlink, which now provides the pathway for local renewable energy projects, enables us to develop Imperial County’s abundant renewable energy resources while also preserving our natural resources and native habitat.