Renewable energy developer Terra-Gen LLC and construction company M. A. Mortenson Co. Inc. completed the massive Edwards & Sanborn Solar and Energy Storage station, touted as the largest such operating hybrid power plant in the US, three years after breaking ground.

"This is probably the most complex project any of us have ever worked on, probably the most high impact as well," James Phaneuf, Mortenson's vice president and general manager for energy storage, said in an interview. "It's such a large project that it has a substantial impact on helping to balance the grid in California."

Mortenson completed construction in November 2023, and the US Air Force's 412th Test Wing, the host for Edwards Air Force Base in Southern California's Mojave Desert, unveiled the multiphase battery-backed photovoltaic (PV) facility in early February. Stretched across 4,660 acres in Kern County, Calif., the project combines 971 MW/3,287 MWh of energy storage resources — including lithium-ion batteries from LG Energy Solution Ltd., Samsung SDI Co. Ltd. and BYD Co. Ltd. — with 807 MW of First Solar Inc. thin-film PV arrays steered by Nextracker Inc. sun-tracking systems.

Such hybrid battery power plants, along with stand-alone storage facilities, have emerged as essential tools in efforts to reliably decarbonize the US power grid.

Nearly 9 GW of battery power storage capacity was online at US power plants as of Feb. 6, mostly installed at new and existing facilities over the past three years, according to S&P Global Market Intelligence data. Roughly 3 GW came online over the past year.

About 80% of hybrid battery storage in operation is paired with solar, and 14.6% is colocated with natural gas-fired facilities such as Vistra Corp.'s Moss Landing Battery Storage Facility in Monterey County, Calif., currently with 750 MW of four-hour energy storage. Another 4.4% is connected at wind farms.

'Very bullish'

The Edwards & Sanborn facility supplies power to numerous California utilities, community choice aggregators and corporate customers, including PG&E Corp. operating utility Pacific Gas and Electric Co., Edison International subsidiary Southern California Edison Co., Clean Power Alliance of Southern California, East Bay Community Energy, San Jose Clean Energy and Starbucks Corp.

"We're very bullish on this type of asset and this type of model," Phaneuf said, adding that the project employed over 1,000 workers "and tons of apprentices building up to do future jobs."

It appears there will be no shortage of opportunities.

The US hybrid storage pipeline includes over 49 GW of planned battery power capacity, 94% of which is colocated with solar farms, Market Intelligence data shows. The remainder is planned primarily at gas plants at wind projects.

"Almost every single new solar plant that is being contemplated ... is putting a battery on it," Phaneuf said.

The Inflation Reduction Act of 2022, which includes valuable tax incentives for energy storage and renewable energy projects, was a "shot in the arm" for such hybrids, Phaneuf added. "Four or five years ago, I think that there were some questions on whether the economics of doing these types of projects would really pay off," the executive said. "And I think what we're seeing ... is that the economics of these types of projects work and show a really good path to a fully renewable future."

Over 300 energy storage projects, or major project phases, with battery power capacity of at least 500 kW are in operation at US power plants, according to Market Intelligence data. That includes 76 such hybrid facilities in California, 22 in Texas, 18 in Arizona, 17 in New York and eight in Nevada.

At least another 373 battery projects, or major phases, are planned around the country, mostly in the Southwest and Texas, with ever larger storage systems.

More than 180 of the planned hybrid projects have battery power capacities of at least 100 MW, compared with just 33 projects of that scale now online. Several of the planned projects have battery systems bigger than the Edwards & Sanborn complex.

"We're seeing a lot more projects of this scale and size popping up across the Southwest [and] even across the country," Phaneuf said.