Project Highlights
- The 500-kilovolt transmission line was recognized by the U.S. Department of Energy as a critical infrastructure project for the Desert Southwest region.
- The transmission line was a Federal Energy Regulatory Commission Order 1000 project designed to increase the regional capability of the electrical grid in delivering new renewable energy, enhance operational flexibility, and strengthen reliability in the Southwest.
- The project accommodates the interconnection of future renewable energy resources in both Arizona and California to the bulk transmission grid, helping modernize and diversify the region’s infrastructure.
- The transmission line’s selected route reduced impacts to the surrounding area, including the Kofa National Wildlife Refuge and tribal lands, by maximizing the use of designated utility corridors and existing access roads to conserve resources.
Project Description
The 500-kV Ten West Link Transmission Line spans 125 miles between Southern California and Central Arizona. The Lotus Infrastructure Partners project supports the region’s potential for large-scale solar energy development in creating an interconnection to the bulk electric grid that helps the two states reach their renewable energy standards and carbon reduction goals.
This project was sponsored by the California Independent System Operation Corporation, which oversees the operation of the transmission line. The transmission line was designed for 3,800 amps continuous with 25% series compensation station (SCS) provided to the line to increase power transfer capacity and improve voltage stability.
Project Scope
Sargent & Lundy was the project’s independent engineer and was hired to perform technical due diligence reviews during major steps of the project life cycle, identify and mitigate potential design flaws, and verify use of good utility practice. As independent engineer, the firm performed review activities for the transmission line design, the series compensation design, environmental permitting approaches, the construction contract and the operations and maintenance agreement. Sargent & Lundy also provided a financial model assessment to support project financing and recommendations, where appropriate, to help stakeholders mitigate potential issues and concerns.
Additional review activities included:
- Design criteria and electrical studies.
- Structural design for tower and tubular steel including tower testing.
- Transmission line design using PLS-CADD.
- Hardware and assembly design.
- Project material and construction specifications.
- Transmission line foundation and anchor design.
- Constructability and feasibility reviews.
- SCS schematic and communication drawings.
- SCS cable schedules.
- SCS calculations.
- SCS civil, physical, and structural designs.
- Environmental permitting.
- Facility inspections for acceptance testing, quality, and expediting.
- Equator principles environmental assessment.
Sargent & Lundy’s role during the construction phase included onsite independent engineering construction monitoring and services to observe compliance with both project design and good utility practice in support of independent engineering project financing certifications. Deliverables included:
- Monthly independent engineering site inspections of project construction.
- Monthly construction status reports.
- Construction production reporting reviews.
- Independent engineering support to review construction requests for information and identify conformance with project design documents.
- Project invoice reviews to verify alignment with the project financial model.
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