Long a leader in the push to reduce vehicle emissions and switch to renewable energy, California marks another milestone this week.

The last of three battery energy-storage sites will come online in Southern California, providing storage and buffering for unpredictable renewable energy.

Together, the three sites add up to capacity equal to fully 15 percent of all battery storage installed last year—on the planet.

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While California had passed an energy-storage mandate, development didn't kick into high gear until the huge leak in a natural-gas storage facility in Aliso Canyon that was detected in October 2015.

That months-long leak was an environmental disaster, releasing greenhouse-gas emissions equivalent to the annual total from 1.7 million road vehicles. It also cut off fuel supplies to local power plants. 

That led regulators and utilities to look for more flexible ways to deliver electricity and boost the role of renewable sources—including large-scale wind and solar installations far from urban centers—to reduce the risk of winter blackouts.

Tour of Tesla battery gigafactory for invited owners, Reno, Nevada, July 2016

Tour of Tesla battery gigafactory for invited owners, Reno, Nevada, July 2016

As a recent article in Bloomberg describes, the three battery storage sites are fully "grid-scale," far larger than mere pilot or experimental programs.

Each of the three was built by a separate company, and all three were completed in the remarkably short time of six months.

AES used Samsung lithium-ion cells in the energy storage array it built for San Diego Gas & Electric (SDG&E) in Escondido, California, about 30 miles from San Diego.

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Billed as the largest installation of its kind in the world, that 120-megawatt-hour site can deliver 30 megawatts, or enough to power about 20,000 homes for four hours.

Tesla, meanwhile, has completed an 80-Mwh array of its commercial-scale storage batteries for Southern California Edison near Chino, California, capable of delivering 20 Mw.

The third battery-storage site was built in Pomona, California, by Altagas Ltd. Opened in December, its 80-Mwh capacity can deliver 20 Mw for four hours.

San Diego Gas & Electric substation

San Diego Gas & Electric substation

Energy storage is frequently discussed as an adjunct to renewable energy, because it provides electricity even when the sun is not shining or the wind is not blowing.

But it also benefits utilities by evening out the load on generating resources, which in turn reduces stress on the distribution grid.

Energy-storage batteries can be charged during periods of low demand, and discharged when demand increases.

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In California, energy storage is also designed to reduce dependence on the expensive natural-gas "peaker" plants used to meet sudden demand spikes because they can quickly start producing power.

California mandates require utilities to add more than 1.3 gigawatts of charging capacity in the state by 2020.

Last year's total energy-storage market provided less than 1 gigawatt of capacity globally.

Tesla CTO JB Straubel and CEO Elon Musk presenting at gigafactory tour, Reno, Nevada, July 2016

Tesla CTO JB Straubel and CEO Elon Musk presenting at gigafactory tour, Reno, Nevada, July 2016

A portion of the lithium-ion cell output from Tesla's multi-billion-dollar gigafactory outside Reno, Nevada, will be devoted to energy storage uses, not only Tesla's electric cars.

“It’s sort of hard to comprehend sometimes the speed all this is going at,” Tesla CTO JB Straubel told Bloomberg.

“Our storage is growing as fast as we can humanly scale it.”

[hat tip:Randall Hamlet]


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