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Primus May Name Wind Power Storage Customer Next Month, CEO Says

May 21 (Bloomberg) -- Primus Power, a closely held battery maker, may announce next month a third customer that’ll use its systems to store excess power from a wind farm, according to Chief Executive Officer Tom Stepien.

The project will be in an area with mostly hydro, coal-fired and wind generation on the local grid, where excess wind power can become an issue depending on weather, Stepien said today in an interview at the Electricity Storage Association’s annual conference in Santa Clara, California. He wouldn’t identify the customer or say where the project will be located.

The company’s customers include the Modesto Irrigation District and the U.S. Marine Corp. Primus’s systems consist of “refrigerator-sized” batteries that are packed inside shipping container-like “energy pods,” Stepien said. Because they’re portable, they also may be used near utility substations, which in some cases may delay the need to build new transmission, he said.

Those applications already have attractive economics, and “if you have a capital cost below $500 per kilowatt-hour, the market really opens up,” Stepien said. “That’s the tipping point.”

Utility Modesto is planning to use 28 megawatts of the company’s batteries to provide as much as 3 hours of energy storage, Stepien said. A Marine Corps base in Miramar, California, plans to use a single 250-kilowatt energy hub to store power from a 230-kilowatt photovoltaic array, he said.

Flow Batteries

Primus, based in Hayward, California, expects to begin those deliveries next year, Stepien said. Its flow batteries have an electrolyte consisting of zinc-bromide that’s cycled through a reaction chamber.

The company’s “early adopters” will be utilities and operators of wind farms and solar arrays, Stepien said. “We want to be an arms dealer to a lot of the integrators,” or project developers, he said. Robert Bosch GmbH and Raytheon Co. are development partners for its Modesto and Miramar projects, respectively.

Primus, which is backed by investors including Kleiner Perkins Caufield & Byers, has raised $15 million in two funding rounds and plans to complete its third before the end of the year, Stepien said. It’s also received $17 million in government grants that are being drawn down in phases, he said.

The company doesn’t plan to build any manufacturing plants, which helps keep costs low, Stepien said.

To contact the reporter on this story: Andrew Herndon in San Francisco at

To contact the editor responsible for this story: Reed Landberg at

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