Published on June 8th, 2014 | by Jake Richardson


Almond Farm Is Site Of New Flow Battery Powered By Solar

June 8th, 2014 by  

An almond farm in the Turlock, CA area might not sound like the most likely place for new flow battery technology, but that is exactly where EnverVault decided to locate a demonstration-size iron-chromium redox flow battery. Its capacity is one megawatt-hour of energy for four hours and it is situated near a 150-kilowatt solar system and an electric irrigation pump.

Image Credit: Enervault

Image Credit: EnerVault

Energy stored during daylight hours can be used to operate the pump at night to irrigate about 300 acres of almond trees.

At the dedication ceremony, CEO Jack Pape, said, “Our mission is to safely and reliably deliver grid flexibility to the California market and to the world market.”

An electrolyte is pumped through a stack of electrochemical cells to generate electricity. The technology is housed in huge steel cylinders; two of them placed side by side are about the size of two shipping containers stacked vertically. The electroylyte is mostly water, which is obviously abundantly available and at very low cost.

Other advantages of its flow battery are that it is less flammable than lithium-ion batteries and non-toxic. They do require more space to be installed due to their large size. The technology can scale, however, because adding more towers and cells is fairly easy.

We’ve been hearing a lot about Tesla’s gigafactory, but EnerVault’s flow battery is relatively simple in design and uses more common materials. “I don’t have to have a factory. All I need to build is the cells and stack – there is no gigawatt factory required. I am going to be the big energy storage guy because the tanks come from a supplier, the pumps come from a supplier. Power conditioning and controls – all arrive at the job site with my cells and stacks, so I don’t have to inventory. I have a very cash efficient business model, with 80% as pass through. We will make an announcement shortly with respect to a partner who can build these facilities at low cost. This scales rationally and fairly easily – there’s no $5 billion gigafactory,” explained CEO Jack Pape.

Pape started the grid storage company in a Sunnyvale garage in 2008. He is also a former executive at SunPower, and some other EnerVault employees are from the PV company also.  (A former VP of manufacturing at Tesla is also on board at Envervault.)

US Invest, Oceanshore Ventures, Mitsui Global Investment, Total Energy Ventures, and TEL Venture Capital are some of EnverVault’s backers. Analyst Sam Jaffe said the market for energy storage batteries could be over $20 billion by the 2020s.

Though Silicon Valley is known as a place where software engineers constantly pound out code, chemical engineering is a little more challenging than developing the next app.

“Nature doesn’t like to store energy,” explained Craig Horne, a co-founder of EnerVault. “That energy is going to want to release. And that’s why energy storage has always been such a challenging technology to commercialize because, in a way, you’re defying nature.”

If successful on a large scale, energy storage is also going to be much more impactful than the next social media site. I would be curious to see if there is any viability for a flow battery system to work with CSP, rather than thermal storage.

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Hello, I have been writing online for some time, and enjoy the outdoors. If you like, you can follow me on Google Plus.

  • Bob_Wallace

    Turkeys from Turlock!

    Turkeys from Turlock!

    (I have some history there. ;o)

    ” iron-chromium”

    Anyone with enough chemistry background to tell what the ingredients might cost and how corrosive they might be? Are we talking simple steel containers or stainless steel/whatever?

    Do those tanks look insulated?

    Any reason to think this might be more/less expensive than vanadium redox flow batteries?

    Inquiring minds, as well as mine, want to know more.

    • eject

      Anything will be cheaper then vanadium. You can certainly contain them in plastic or enamel. Iron is cheap as dirt from a battery point of view. Chromium does cost more and yet we use gigantic amounts for stainless steel and coating all sorts of things. Price wise this should be quite a leap from vanadium.

      • Bob_Wallace

        Thanks. What I have mostly seen is a claim that vanadium flow batteries would cost ~8/kWh for frequently cycled storage (once or so per day). If these batteries will turn out cheaper then we’re in great shape.

        I would assume these puppies could be housed underground as well as over. That would mean that we could put them in commercial/warehouse buildings and get them out of sight. Easy to site. We could do multiple basement levels in densely packed cities to create neighborhood storage.

        Wonder how the Ambri liquid metal battery is progressing?

        • bink

          Bob, really? I told you to stay out of the battery debate.

      • bink

        eject, get your facts straight, AVRB has the lowest LCOE installed due to its 20yr design life in which you do not have total battery replacement nor degradation of electrolyte with unlimited cycling.
        It has lower O&M and no special storage, in addition the operating range is wider for cold or hot climate.
        I wont give you everything but will wait for your response in which you will look not so smart

        • eject

          Where do I have written anything about AVRB, I don’t even know what it stands for. I have written about raw material prices. If you have missed that you lack English comprehension skills which for an obvious native doesn’t make you look so smart.

  • Renewable Energy

    Would like to see a comparison between the iron-chrome chemistry versus the zinc iron chemistry being developed by Vizn Energy.

  • Matt

    I notice that there is no price quote for the “megawatt hour for four hours”. Units are off there. Maybe because they price different? There is the cells (which control charge/discharge rate) and the then the tanks and electrolyte which control total storage.

    • CsabaU

      “megawatt hour for four hours” =1 MWh/4h=250kW.

      • bink

        CsabaU, a more accurate way of stating that would be”megawatt for four hours” = 1 MW/4 MWh = 250kW. Not your fault, the way the author stated it would confuse someone with less knowledge regarding storage than yourself.

      • Rob Lewis

        Yet another media report that can’t figure out the difference between Power and Energy. “one megawatt-hour of energy for four hours” simply makes no sense.

    • bink

      Matt, flow battery architecture and platform allow for independent power and energy rating which makes scaling up easier. If you need to add more power (kW’s) to handle an increase in building load, then you only need to add cell stacks and nothing more.

  • Wayne Williamson

    Cool tech.
    I think the CEO is missing the boat in his comparisons to the gigafactory. The idea is to produce massive amounts at the cheapest price you can. Maybe he should be doing this to. Just say’n.

    • A Real Libertarian

      Plus flow batteries are unsuitable for EVs.

      • bink

        There are buses that run off of flow batteries

        • A Real Libertarian


    • bink

      he doesn’t need to invest in that infrastructure and labor. His model is similar to a Google or Apple they farm out the manufacturing. Only assembly does not take place in a factory The tanks and balance of system (pumps and pipes) are off the shelf parts which can be assembled on site. The cell stack harness assembly is purchased from a OEM and the BMS (battery management system) or converter/inverter is OEM. Assembly can take place on site and as a company you can still scale

      • jeffhre

        When did work on site become cheaper than in a factory? I know, I know, parts are manufactured as commodities in factories and shipped to site – but at a system scale, it is still all on site?

  • JamesWimberley

    Night-time irrigation looks a good application for storage. As against daytime irrigation, it cuts water loss to evaporation by from a third to a half (source: Clemson, link). In much of the world, water is a scarce resource and climate change is making it both scarcer and more necessary.

    • Jake R

      That soup sounds very good. Thanks!

    • jeffhre

      Yes, the melon garnish is an awesome idea, temps hitting 106 in some spots here this week, your timing couldn’t get better while we are adjusting to the heat. That was one heck of a segue though!

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