Terra-Gen and Mortenson have announced the activation of the Edwards & Sanborn Solar + Energy Storage project, the largest solar-plus-storage project in the United States. Mortenson served as engineering, procurement, and construction contractor for the project.

The project is a true renewable energy behemoth, spanning 4,600 acres, comprised of 1.9 million US-made First Solar panels. It holds a capacity of 875 MWdc solar, and nearly 3.3 GWh of energy storage. It has a 1.3 GW interconnection capacity.

California’s grid is expected to receive enough electricity to power the equivalent of about 238,000 homes from the project. This leads to an estimated 320,000 tons of carbon dioxide emissions abated annually.

The energy storage is made up of LG Chem, Samsung, and BYD batteries. This feat of engineering required 98 miles of MV Wire, over 361 miles of DC wiring, and 120,720 batteries.

Edwards & Sanborn is partially located on the Edwards Air Force Base in Kern County, California, a hub for many of the largest solar projects in the United Staes. It represents the largest public-private collaboration in US Department of Defense history. Since 2020, more than 1,000 craftworkers contributed to the project, and it was executed with more than a million hours of injury-free labor.

“Only in America can we take barren land, embrace the power of the sun, and create an engineering marvel,” said Brigadier General William Kale, Air Force civil engineer center commander. “So, take the time to reflect, see the great work that was done, and understand the significance of this project and what it can lead to. Hopefully, this is just the spark.”

The active project supplies power to the city of San Jose, Southern California Edison, Pacific Gas & Electric, the Clean Power Alliance, and Starbucks corporation, among others.

The project’s first phase added 346 MWac of solar modules and 1.5 GWh of battery storage. Financing for the the first phase was closed in 2021 and included $804 million senior secured credit facilities. This includes $400 million construction and term loan facility, a $328 million tax equity bridge facility, and a $76 million construction and revolving letter of credit facility. J.P. Morgan is providing the tax equity commitment for the initial phase of the project, with Deutsche Bank leading the construction and term financing.

In 2022, Terra-Gen closed a nearly $1 billion project financing for the second phase of the project. It included $460 million construction and term loan facility, $96 million construction and revolving credit facility, and a $403 million tax equity bridge facility. BNP Paribas, CoBank, U.S. Bank, ING, and Nomura led the funding.

In total, the two financing rounds for the project totaled more than $1.7 billion.