Energy Storage Free-For-All Heats Up With “Ultimate Electron Warehouse”

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Ever since Tesla announced its Powerwall lithium-ion battery last spring, new energy storage solutions have been popping up like mushrooms after a rain. The latest one to pop up is a flow battery from Primus Power. This US company just got a $25 million thumbs up thanks to the global green venture fund I2BF Global Ventures, and an I2BF spokesperson describes the technology as “the ultimate electron warehouse.”

Primus energy storage flow battery

1,250 Flow Batteries For Kazakhstan

For those of you new to the topic, flow batteries generate a charge when two liquids flow adjacent to each other. The technology is a perfect fit for intermittent energy sources, namely wind and solar. Flow batteries can sit idle for long periods without losing their charge, and they can be activated quickly when needed.

CleanTechnica first took note of Primus Power in 2013, when the company made our list of 43 energy storage companies to watch. Fast forward to yesterday’s announcement from Primus, and it seems that we got at least one of the 43 right.

Primus is happy to let everybody know that its Series D financing round, which was headed up by I2BF, netted a whopping $25 million. Other participants included the I2BF-managed Russia-Kazakhstan Nanotechnology Fund along with Anglo American Platinum, Chrysalix Energy Venture Capital, and DBL Partners.

Here’s the rundown from Primus:

Primus is shipping EnergyCells and EnergyPods® — safe, low-cost, modular electrical energy-storage systems. The patented storage technology pairs a unique zinc bromide chemistry with novel technical innovations to deliver optimum performance and multi-decade battery lifetime, at a low levelized cost of energy. Engineered for flexibility and long duration, Primus batteries economically serve a variety of energy storage applications that require multi-hour, daily duty.

Earlier this year, Primus secured its first big order when the principal electric utility for the Republic of Kazakhstan agreed to an order of 1,250 batteries totaling 25 megawatts.

Here’s Ilya Golubovich of I2BF elaborating on the technology’s advantages:

“Storing electrons safely, inexpensively, and with virtually no battery degradation, has long been a strategic imperative for the global energy industry…We are convinced that Primus Power has developed the ultimate electron warehouse.”

With the new round of funding under its belt, Primus also plans to step up its energy storage activities in North America and form partnerships with other energy companies around the globe.

Yes, We Built This Ultimate Electron Warehouse!

In its announcement, Primus Power also gave a shoutout to its public sector funders, which included the US Department of Energy and its high-tech funding arm, the Advanced Research Projects Agency-Energy (ARPA-E), so group hug all you taxpayers.

Primus has been a star performer for ARPA-E. Back in 2010, ARPA-E provided Primus with a $2 million investment. By June 2010, the agency was reporting that Primus had already nailed down $11 million in follow-on funding for its grid-scale energy storage technology, and was in the process of building a demonstration-scale facility for the Modesto Irrigation District in California.

The ARPA-E funding enabled Primus to do some R&D on a new metal electrode that would be less expensive and more durable, and to leverage existing high-volume processes in the metals industry leading to commercial production.

In 2013, CleanTechnica logged in another small-scale flow battery project for Primus totaling 500 kilowatts in Washington State, with partners including the Energy Department’s Pacific Northwest National Laboratory.


The next time we caught up with Primus was just last March, when we caught wind of another energy storage demonstration project that paired the company with NREL, the National Renewable Energy Laboratory. The aim was to demonstrate that a storage-enabled microgrid could enable a particular facility to use all of the solar energy it collects on site.

The demo project took place at the lab and the next step is to deploy it in a microgrid at Marine Corps Air Station Miramar in California. That’s interesting because Air Station Miramar has been working with NREL to achieve net zero energy consumption, defined militarily as “a military installation that produces as much energy on or near the installation as it consumes in its buildings and facilities.”

That’s a pretty tall order for Miramar. An NREL baseline assessment toted up “all onsite buildings plus facilities (Main Base, Brig, Privatized Housing, and Commissary), and fleet vehicles.”

The good news, relatively speaking, is that, according to the assessment, more than 80% of the energy used at Miramar is in the form of electricity, and NREL rated Miramar “good” for solar potential, with geothermal and biomass also potentially chipping in.

The microgrid is being developed by Raytheon, and Primus is contributing its 250 kilowatt EnergyPodTM . Miramar already sports a 230 kilowatt solar array.

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Photo credit (cropped): via Primus Power.

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Tina Casey

Tina specializes in advanced energy technology, military sustainability, emerging materials, biofuels, ESG and related policy and political matters. Views expressed are her own. Follow her on LinkedIn, Threads, or Bluesky.

Tina Casey has 3140 posts and counting. See all posts by Tina Casey

14 thoughts on “Energy Storage Free-For-All Heats Up With “Ultimate Electron Warehouse”

  • Tina, help me out here.
    “Primus is shipping EnergyCells and EnergyPods® — safe, low-cost, modular electrical energy-storage system”
    could you at least include a SWAG at that low-cost so I know if it is even worth digging through pages/pages of text across multiple web site to find it. Assuming that these guys are like the other startup in this area.
    They “sold” 25 megawatts to a electric utility, but you don’t include price.

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    • And: “1,250 batteries totaling 25 megawatts” = 20 KW batteries? Are these going into government buildings? They are not big enough for much else. Not enough for backup on a feeder substation, so interesting but…

      • Can I paste from another site?
        70 percent of its electricity is generated by coal-fired power plants today, but the government has pledged to reach 30 percent renewables by 2030, and 50 percent by 2050.
        “They’re moving toward solar, moving toward wind,” he said. Just this morning, French grid giant Schneider Electric announced a 50-megawatt solar project in the country. “Some of the substations need reinforcement. The northern part of the country is a net producer of electricity, and the southern and western parts are net consumers, so they’re moving electricity around, operating like any other grid.”

  • You need to have a at least a stated price to be considered not vaporware.

  • Was wondering if they make modules for residential applications. Something like 10 kWh, 20 kWh, 50 kWh or 100 kWh.

    • To even consider buying a residential system from a startup, you need an insured warranty from the manufacturer. Few of these companies will still be around in 10 years’ time.

      • Yeah, but if it’s a flow battery it’d probly be 30 year life minimum anyways, I wouldn’t be assured ANY battery company will be here in 30 years, it’s an up and comers market.

    • Well those they sold in the story were 20kWh(if they were all one size), but my guess is they’re not quite yet to the individual consumer sales state.

      • Actually – those they sold in the story were 20KW. Its a power rating, not an energy capacity. This is the crucial advantage of flow cells. Its energy capacity is determined by the size of the tank that holds the liquids and is easily expandable. The battery itself is only limited by power, not really capacity. That is why a 20KW flow cell battery with tanks large enough could supply 20KW for days or even weeks.

        • Very aware how flow bats work. As well as which have sold thus far as well as their look and size. But I guess your explanation can serve an onlooker.

    • See above – they sell with a power rating, not a capacity. The capacity is only determined by the size of the tank and can be essentially unlimited. The restriction on the battery is only the maximum power it can put out. This is a crucial advantage over LiIon, for which cost is dominated by capacity, not power. For flow cells, cost is dominated by power, not capacity. In flow cells, cost for capacity scales linearly with the cost of tanks and fluids, which are relatively inexpensive compared to the battery itself.

  • “flow batteries generate a charge when two liquids flow adjacent to each other”

    thanks for clearing that up

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