First grid-scale battery of its kind unveiled at Calif. farm

Source: Debra Kahn, E&E reporter • Posted: Tuesday, May 27, 2014

TURLOCK, Calif. — In the middle of an almond grove near here, in California’s Central Valley, a first-of-its-kind battery is sharing space with nut trees, solar panels and irrigation equipment.

The 1-megawatt system, which holds four hours of power, is the first large-scale example of an iron-chromium flow battery. According to Silicon Valley startup EnerVault, it’s a major milestone for renewables, grid stability and energy efficiency, as well as the energy storage market itself.EnerVault executives portrayed their company as rejecting the traditional Silicon Valley hype, although the company’s 30 workers were sporting beige polo shirts emblazoned with the date, a description of the battery and a picture of an almond tree.

“We’ve been scaling up logically and methodically,” said CEO Jim Pape. “We’re taking on a market that is now ready to be taken on, and we believe this technology is uniquely qualified to do exactly that.”

The company plans to make its first commercial sale at the end of 2015, for a 1 to 2 MW system, and then by the end of 2016 ramp up to a system of 10 MW or more. Company executives are talking to a utility that serves an island of several thousand residents about replacing its diesel-fueled generation system with solar, biodiesel and a storage system.

Unlike most commercially available batteries today, iron-chromium flow batteries are ideal for storing large chunks of energy and deploying it slowly back to the grid or individual customers. That’s a function that is poised to increase dramatically in the next several years thanks to a burgeoning policy framework, company and government officials say.

Aimed at newly created markets

“We’ve progressed as an industry 10 years in the last year,” said Bret Adams, EnerVault’s director of business development. “There really wasn’t a market for grid-scale storage until nine months ago.”

Several areas in the United States have created markets in the past year, including California’s mandate of 1,325 MW by 2020, a huge move that would increase worldwide energy storage capacity by 50 percent (E&ENews PM, Oct. 17, 2013). In addition, the Long Island Power Authority has issued a call for up to 1,630 MW of distributed storage, generation and demand response, and several international governments like Italy, Germany and Japan are also seen as potential markets.

EnerVault has plenty of federal and state support. Yesterday’s event drew members of three state agencies, the Energy Department, a state lawmaker and a staffer for Rep. Jeff Denham (R-Calif.). It has received $4.8 million from the American Recovery and Reinvestment Act under a DOE grant program for storage demonstration projects.

“What EnerVault is doing is bottling sunshine,” said California Energy Commission Chairman Bob Weisenmiller, echoing remarks Gov. Jerry Brown (D) made last year on the need for energy storage to smooth intermittent solar generation. The CEC contributed about $500,000 to the project.

The technology was developed in the 1970s by a NASA scientist but then lay dormant for decades, waiting for a business case to be made. Starting in 2008, EnerVault began fixating on the iron-chromium “redox flow” model, improving its ability to retain its capacity over multiple cycles and making other improvements. The battery has about 70 percent efficiency, EnerVault says.

Hope for spinoffs

The battery system at the almond farm has four large tanks that contain an energy-rich mixture of iron, chromium and water. The liquid flows through stacks of batteries, where it reacts with electrochemical cells during charging and discharging. It can hold power from the grid or from the adjacent 150 kilowatts of solar panels.

Because the energy is contained in the liquid, and the maximum power is determined by the size and number of cells, the system can be easily adjusted to meet businesses’ needs for either amount of storage or amount of peak power. In contrast, batteries that integrate power and energy within one structure are less adaptable.

And because the liquid has a relatively high volume compared to solid batteries, it’s better-suited for large-scale applications.

Because the materials are abundant and inexpensive, scaling up the batteries and the manufacturing process will be “virtually frictionless” — and there’s “no Gigafactory required,” Pape said, referring to Tesla’s plans to construct a $4 billion to 5 billion lithium-ion battery factory to supply its cars. EnerVault has enough capacity at its Sunnyvale, Calif., headquarters to manufacture 16 MW of power units annually. The rest of the materials come from partners like NorAm, a Canadian engineering company that provides electrochemical fluids.

The system is connected to Pacific Gas and Electric Co. power lines but doesn’t send power back to the grid, or even power the irrigation system on a regular basis. The company is still testing the system for power quality in order to meet its own and PG&E’s requirements.

Policymakers have high hopes for the company. “The projects that I fund should spin off further projects, go out there and conquer the world, and I hope very much that you will be doing it,” said Imre Gyuk, manager of DOE’s energy storage program.