A look at the new battery storage facility in California built with Tesla Powerpacks 

Megan Geuss, ARS TECHNICA
East of LA, a natural gas peaker plant surrounded by fields of cows got a new, futuristic neighbor. Under a maze of transmission lines, a 20MW battery storage facility made of nearly 400 closet-sized batteries sitting on concrete pads now supplies 80MWh to utilities.
The project is an anomaly not just because it’s one of the largest energy storage facilities on the grid in California today, but also because it was built in record time—the project was just announced in September when regulators ordered utility Southern California Edison to invest in utility-scale battery storage, a year after a natural gas well in Aliso Canyon, California, sprang a leak and released 1.6 million pounds of methane into the atmosphere. The leak prompted a shutdown of the natural gas storage facility, one of the largest west of the Mississippi. Regulators were concerned that such a shutdown would cause energy and gas shortages, although that worry has not come to fruition entirely, and SoCal Gas has begun tentatively withdrawing gas again in recent weeks.
The ability to store electricity is something that appeals to state regulators because it also moves toward helping intermittent renewable energy—like wind, which only is produced when wind blows, or solar, which only is produced when the sun shines—become baseload energy. If you can store it after it’s produced, then you can call upon that energy to feed the grid at any moment, even when wind and sun are absent.
The Tesla battery facility is situated on 1.5 acres, and it’s modular in design—two 10 MW collections of 198 industrial-grade Tesla Powerpacks and 24 inverters are connected to two separate circuits at the Mira Loma substation. Unlike its neighboring Mira Loma natural gas peaker plant, which operates to make up for over- or undersupply of energy on the grid, the new battery facility operates only when there’s immediate demand. Southern California Edison’s market operations group submits bids for the energy at the battery plant and the California Independent Systems Operator (CAISO), a nonprofit that oversees the state’s electric system, will award the bid if a customer needs that battery power.
Read more at: A look at the new battery storage facility in California built with Tesla Powerpacks | Ars Technica