The largest solar storage project in the US

Working closely with Mortenson and Terra-Gen, Coffman provided multidiscipline engineering services to support the design, fabrication, permitting, and construction of the largest solar and energy storage project in the United States. The Edwards & Sanborn solar storage project is partially located on private land and the Edwards Air Force Base in Kern County, California. This project represents the largest public-private collaboration in U.S. Department of Defense history.

This project spans 4,600 acres and is comprised of 1.9 million First Solar panels. It has a capacity of 875 MWdc solar, nearly 3.3 GWh of energy storage, and a 1.3 GW interconnection capacity. This equates to producing 1,300 MW of power to the California grid. The active project supplies power to the city of San Jose, Southern California Edison, Pacific Gas & Electric, the Clean Power Alliance, and others.

Coffman’s multidiscipline engineering capabilities and collaborative team allowed us to provide structural, electrical, mechanical, fire protection, corrosion, and acoustical engineering services to support Mortenson, the project’s EPC (Engineer, Procure, Construct) contractor from design services through equipment fabrication and construction. In addition, Coffman provided third-party engineering reviews and design support for multiple different custom designed BESS enclosures. Over a three-year period, Coffman provided more than 20,000 hours of design and consulting support.

“The Edwards & Sanborn solar and energy storage project is an incredible example of a successful partnership between utilities, power producers, contractors, and engineers, delivering results. This project is a huge win for clean power production and improving the resiliency of the grid,” said Tony SlatonBarker, PE, Vice President of Energy and Sustainability.

“This project is one of Coffman’s largest alternative energy projects to date. Our long-standing partnership with Mortenson and their dedication to teamwork with Terra-Gen and all project stakeholders were major factors in its success. We look forward to many more alternative energy projects with Mortenson and Terra-Gen in the years to come.”

Coffman’s main efforts of involvement included:

  • Complete peer reviews for the design of multiple custom battery enclosures and battery types for electrical, structural, mechanical, and fire protection.
  • Complete fabrication shop inspections and design verification across four different US fab shop facilities for multiple custom battery enclosures for electrical, structural, mechanical, and fire protection. Observation of equipment and system testing was observed and validated.
  • Structural engineering for the seismic analysis of the battery racks, foundation upgrade recommendations, and third-party review of steel and precast concrete enclosure designs.
  • Electrical engineering support for the preliminary fault current analysis for the BESS enclosure manufacturer and design modification for BESS enclosure configurations.
  • Mechanical third-party review of the BESS enclosure, which uses rooftop HVAC units independent CFD analysis to direct a design that is compliant with the battery manufacturer’s requirements; full review of HVAC units to confirm their ability to deliver the right air temperature; witness and approver of factory acceptance testing and site commissioning.
  • Fire protection consulting for proper smoke detection sensitivity. Proper control logic and fire suppression sequence of events for the detection and releasing systems were confirmed critical.
  • Acoustical consulting was provided to determine appropriate noise limits for the project site. In addition, Coffman updated the noise model, analyzed equipment barriers and their effects on the project noise level, modeled noise and vibration from the construction equipment, and measured long-term and worse-case noise data for compliance with local regulations.

Additional information about the project can be found on Mortenson’s website.

Images courtesy of Mortenson/Terra-Gen