Batteries zinc air inc zinc iron redox flow battery

Published on April 22nd, 2013 | by Zachary Shahan


Zinc-Iron Redox Flow Batteries — The Next Big Thing In Energy Storage? (CleanTechnica Exclusive)

April 22nd, 2013 by  

zinc air logoI recently had the opportunity to chat with the CFO and President of Zinc Air Inc., Craig Wilkins, as well as one of the company’s advisors, Greg Hayes. It was a very interesting discussion and it looks like Zinc Air Inc. has what could be a very promising grid storage technology, and the technology is just about ready for market. As always, we will have to see how the market responds. However, for now, below is a bit of info for you to chew over.

First of all, despite the name (I’ll come back to that), the company isn’t developing zinc-air battery technology, but rather zinc-iron redox flow battery technology. Its key benefits, according to Wilkins, are: “reliability, durability, safety, and low cost.” (I’ll delve in a little more near the bottom of this post.)

Despite its wide array of claimed benefits, you probably haven’t heard about this company before. The reason, according to Hayes, is that they haven’t had to go the megaphone-advertising, attract-investors route — the startup has been funded by a handful of wealthy individuals. “We’ve been able to raise a lot of capital through private, high-net-worth individuals,” Hayes added. And I could hear the gratefulness in Hayes and Wilkins’ voices. They are well aware of the fatigue investors, experts in the field, and the broader public have from overhyped technologies that never make it to market.

As noted at the top, Zinc Air Inc. (ZAI) is just about 6 months out from its technology being used in its first commercial project. As such, the company is coming out from under the radar more.

The company has been around for about four years in total, mostly working on nitty gritty of its zinc-iron redox flow battery technology. This is following about eight years of DOE-funded research. “We have been spending a great deal of that time developing the technology,” Hayes said, but he added that they have also been working on business outreach for the last two or three.

Rather than simply trying to sell the idea to investors, however, they have been connecting with leading utilities (including the largest renewable energy utility in the US) and other potential customers. ZAI has a “2013 pipeline of $16 million in sales, with follow-on projects of $115 million,” a company document that was sent over noted. And the company currently has no debt.

Basically, the company is trying to fill some niche needs at the moment, while proving commercial viability and preparing itself for greater market expansion. The first, “easy” markets to penetrate are behind-the-meter microgrid generation, Wilkins notes. But, in general, the aim is for use as a conventional grid storage technology (projects in the tens of megawatts). To date, Wilkins says, “we have had due diligence performed on us by the largest customers.”

zinc iron redox flow battery zinc air inc

zinc air inc zinc iron redox flow battery

The company is looking at international markets as well as the US market. In particular, due to Germany’s relatively high level of renewable energy penetration (and renewable energy competitiveness), it is a key market ZAI is looking at, and it has had a lot of discussions with key firms there. It has also had a lot of discussions with various Indian groups. Solar is now cheaper than fossil fuels in India, a lot of people are still without electricity (or reliable electricity) there, and there is a large governmental push for solar and wind power growth. I would think that India is one of the most attractive microgrid markets in the world, so it’s no surprise to hear that ZAI is eager to get a foothold in there.

Zinc-Air Batteries

When the company started, it had just acquired zinc-air technology rights from Lawrence Berkeley National Labs. That’s where the name comes from. They actually still have a side company still working on zinc-air battery technology for some niche markets, but it didn’t see zinc-air technology as the best option for grid storage. Cycle life and efficiency issues make zinc-iron redox flow batteries a better grid storage option, in their eyes. Also, Wilkins noted that flow batteries scale more naturally.

Wilkins’ team has been able to get up to 100 cycles on its zinc-air batteries, and it is looking to get up to 1,000, but the demand for conventional grid storage application is for 7,000 to 10,000 cycles.

Anyway, that’s a side tangent — let’s get back to the zinc-iron redox flow batteries it says are just six months out from first deployment. There must be a lot of technical information available, right?

Zinc-Iron Redox Flow Batteries

First of all, ZAI states that its batteries are super safe, and that safety was a key focus from the beginning, and one reasons why they chose this technology over others early on in the technology planning. “I can de-energize our battery in 15 seconds in case of any natural or man-made disaster,” Wilkins stated. They operate at ambient temperatures. They are not pressurized. And they are “closed loop” — meaning there is no potential for hazardous gases or waste by-products.

The system is an alkaline-based system. You would be able to pull off-the-shelf components together for this product. (Of course, the company has been patenting away — it has 2 patents and 15 pending patents.)

ZAI is expecting this to be a 20-year battery.

6 prototypes have been tooled and tested over the past three years. Over 200 iterations have been tested, and tens of thousands of cycles in (total) have helped to demonstrate their real-world reliability.

In some follow-up questions regarding how deep they have been cycling the batteries, efficiency, and how the batteries perform in various temperatures, I got these responses from Wilkins:

The benefit of flow batteries is the “dynamic range” or the ability to use the full state of charge range. For our lifecycle testing, we use deep cycles going from 100% to 0-5%. In addition, we test using short/shallow cycles to replicate frequency regulation profiles. Our AC/AC efficiency is 72-75%.

Our battery is optimized to operate at 50°C. Our battery is very tolerant of temperature changes without significant impact to performance.

All good-looking answers to me. But I know some of our readers have much more expertise in battery technology, so I’m eager to read what you think. Naturally, we have to wait to see if the statements above hold true in commercial operation, but this is certainly a grid storage company I’m going to be keeping an eye on.

The Zinc Air Inc Team

Before giving you readers the floor and seeing what you have to say in the comments below, one last thing worth noting, I think, is the current ZAI team. The company has a pretty impressive Technical Board of Advisors and Business Board of Advisors. And I think its Management Team help to explain why.

I’d encourage checking out everyone on the squad, but a few notes I’ll throw in here are that there are six PhD holders on the Technical Board of Advisors, and the company’s CTO (who holds a PhD in Chemistry from the University of Victoria) was previously Coda Automotive’s Vice President for Electrochemical Research (where he was responsible for cell research, quality, and safety). Prior to that, Dr. Ron Brost was with Ford Motor Company for 12 years “as a Technical Expert and supervisor for multiple advanced battery technology teams that developed fuel cell, battery electric, and hybrid vehicle energy storage systems.” He was also the Chairman of Ford’s Fuel Cells Patent Committee for six years.

Anyway, again, I recommend checking out the full Zinc Air Inc team if you are interested in learning more about this company.

Overall, the company motto, according to Wilkins, is: “Big. Safe. Cheap.” We’ll see!

This post was updated at 2:21pm EDT on April 22 to correct a typo and a misquote. In one place, “sinc-iron” was changed to “zinc-iron.” Additionally, “I can de-energize our battery in 15 minutes in case of any natural or man-made disaster” was changed to “I can de-energize our battery in 15 seconds in case of any natural or man-made disaster.”

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About the Author

is tryin' to help society help itself (and other species) with the power of the word. He spends most of his time here on CleanTechnica as its director and chief editor, but he's also the president of Important Media and the director/founder of EV Obsession and Solar Love. Zach is recognized globally as a solar energy, electric car, and energy storage expert. He has presented about cleantech at conferences in India, the UAE, Ukraine, Poland, Germany, the Netherlands, the USA, and Canada. Zach has long-term investments in TSLA, FSLR, SPWR, SEDG, & ABB — after years of covering solar and EVs, he simply has a lot of faith in these particular companies and feels like they are good cleantech companies to invest in. But he offers no professional investment advice and would rather not be responsible for you losing money, so don't jump to conclusions.

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  • JustSaying

    On thing you can be 100% sure on, is no one’s guess about what energy production/storage will be in 20 years will be 100% right. Things are changing fast.

    I do think the Arctic going ice-free could be a wake up call to many people. Maybe enough to get carbon tax pushed through in the big hold outs. China’s already talking about it. If US rates double on the east/west coast and tripled in the center; there would be a massive move here.

    Also there are already places where the batteries don’t have to be super cheap to make money. In Texas many night whole sell power is free (or negative) and peaks are high (was a CleanTechnica post this last summer if memory serves), In fact I thought that the story mentioned somewhere in Texas with very cheap or free retail power at night, trying to get demand shifting. If you are a wind farm or a big industrial user that spread pays a big return.

    • Bob_Wallace

      You can see Texas wholesale prices here.

      If you take a look at HB West prices for 4/23/2013 you’ll see a spread between -15.46 and 26.04/MWh. But those kinds of prices don’t happen often enough to make current storage pay.

      If ZIA, EOS, Ambri or another of the companies working on cheap grid storage can bring their product to market then this might happen.

      • brink

        bob you are looking at the wrong penetration for storage. it is going to be at the non generator substation for peak shaving where it is profitable. selling energy is a minimal benefit

        • Bob_Wallace

          That’s near term.

          Longer term we’re going to be storing wind and solar in large amounts for use hours later.

    • I actually differ a bit from you two here — regarding the Arctic. I think the Arctic is too distant and abstract a thing for the common person. Don’t think it will stimulate much additional concern/action. Think of those things Jay Leno and/or David Letterman always did where they asked people on the street basic questions and the answers were ridiculous. I think the things that will wake up the masses are more natural disasters like Sandy & Katrina, and more extreme & extended drought & heat waves. But we’ll see…

      • Bob_Wallace

        Sandy and Katrina were “just some more hurricanes”. Katrina was a bad storm but the most remarkable damage, the flooding of New Orleans, was a levee failure. The Northeast had been hit by hurricanes before. No new news in these cases, just replays of stuff people had seen before.

        When the Arctic Ocean melts for the first time, which is looking like 2016, it will be something that humans have never seen before. We have all grown up with the idea that north of Canada is a great big block of eternal ice. It’s Santa’s home, for god’s sake.

        The media will be full of videos of planes flying over open ocean where we have hundreds of years of human history of seeing thick ice in the hottest of summers.

        I think this will push a number of people off the fence. Many who “sort of believed’ in climate change will find their opinions firmed up. Those who try to argue that “it’s just gotten a little warmer from time to time” will get this massive melt shoved in their faces.

        It’s going to take a lot of people by surprise because they are watching area/extent and not paying attention to volume/thickness which is harder to see. Most don’t realize how thin the ice has become and once the multi-year ice is gone how likely it will be that the thinner one year old ice will perish under the summer Sun.

        But most important, the people who really make decisions, governmental leaders, will be given a wake-up call that climate change is not something that might happen later. It already has happened and we’ll watch the ice melt each summer as a reminder.

        Then. And this could be the real kicker, it’s unlikely we can expose that much water to direct sunlight without changes to the weather much further south of the pole.

  • The roundtrip efficiency of 72-75% is a deal killer. I hope they will improve this to near 90-95%. No wonder it generates a lot of heat and the need to tolerate that heat. So if they get the electricity at $0.05/kWH off peak then, they have to sell it at $0.07/kWH just to break even with losses, then add to it the other costs, finance charges, salaries, depreciation….

  • Bob_Wallace

    Zinc Air Inc. (ZAI) is just about 6 months out from its technology being used in its first commercial project.

    ZAI has a “2013 pipeline of $16 million in sales

    We’ve got three or four grid storage battery technologies claiming commercial level production in the next year or two. Only one has to come through (at an affordable price).

    If storage happens and if the Arctic Ocean goes ice-free in the next 2-3 years we should see an immense move to renewables. Generation is already affordable.

    • Otis11

      If we get one affordable, scalable storage technology, it’s only a matter of time.

      Here’s how I see it – Even with conventional FF generation, we waste a lot of energy for the sake of grid stabilization, producing more than we need because we cannot ramp up and down fast enough. Additionally, because of the fluctuations throughout the day, and the inefficiencies of thermal plants scaling on daily changes (with the exception of designed peaker plants, but those are already more expensive) and the additional stresses put onto thermal plants by constant cycling, many companies will add storage simply to allow their FF plants to run at more constant levels, ramping up and down more slowly and less often, and thereby increasing their generation efficiency as well as extending plant life and minimizing repair costs.

      But, as soon as the storage is there, it then still makes (economic) sense to use the storage primarily for the cheaper renewable generation that is not demand responsive and scale the FF plants up and down anyway. Since it was economical to make the battery backup for the thermal plants originally, it will still be economical to make another battery backup for the thermal plants (since the original backup got taken away to be used even more economically by renewables). This again adds overhead that renewables can use. As more renewables come on line and use more and more of this storage, the cycle repeats.

      Eventually almost all thermal plants will be forced out by their own economics. The only prerequisite is batteries cheap enough to be economical for the scaling of thermal power plants. Once that happens it’s game over.

      • Bob_Wallace

        Good point about using battery storage to let fossil fuel plants run at their most effective speeds rather than ramping up and down.

    • Adam Grant

      Business decision makers aren’t concerned about the Arctic, or the environment in general, and the fossil fuel industry has slowed the pace of new regulations.
      Ultimately the rising cost of fossil fuels is going to be what tips the balance, and there the outlook is bright. It’s reasonable to believe that the cost of oil will rise significantly in many countries over the next few years, particularly those that depend on imports. The rising cost of oil will also increase the cost of coal and gas extraction significantly. Coal in particular is bulky and can’t travel via pipeline, so must be moved around by internal combustion engines.
      The current overcapacity among solar cell producers may prove to be a good thing once the business case for renewables becomes clearer and everyone suddenly wants to install panels.

      • Bob_Wallace

        I’m not suspecting that the Arctic melt will have a big impact on how the fossil fuel industry acts, but I do expect to see it greatly ramp up public opinion for getting something done about our greenhouse gas problem.

        I think we’re looking at a cost decrease for coal. There’s already a fair amount of discussion about how companies that own coal resources may not be able to sell all their product as we shut down coal use. We’ve reached the point in the US at which coal producers are trying to find a route to get product to the West Coast in order to ship excess to China.

        I don’t think we’re looking at very much increase in oil prices over the next several years. I know there are people who are predicting a sudden shortfall, a peak, but they’ve been making that prediction for years.

        I think we’re short years from an EV battery that will give us enough range to drive all day with a couple of <20 minute recharge stops. When that happens it's over for oil. The cost of driving with electricity is so much cheaper that oil will be forced off the personal transportation market.

        Anyway, those are my guesses…

  • Otis11

    Sounds great – and won’t have to wait too long for a final judgement if they’re starting industry scale tests this and next year! Look forward to hearing more about it!

    “sinc-iron” Hmm… sinc. That’s a new one. =-P

    • ha, thanks, snipped that one yesterday, as well as a ‘slight’ misquote.

  • JMin2020

    Thanks for the post Zach. Zinc Air Inc. did a good jub of keeping this under wraps. I believe they have something here.As a REDOX flow battery sysrem; this must compare in efficienct to the Flouride Shuttle process developed just a couple of years ago as well.

    • yeah, i was surprised i hadn’t heard of them… until he noted that they were keeping themselves on the down low.

  • Ross

    How do the costs of this compare with using surplus renewable energy for power-to-gas based on the Sabatier reaction?

    • Ronald Brakels

      Well, we don’t know the cost of this system yet, but at least we know that this is more energy efficient than producing methane gas with the Sabatier reaction. I would be quite surprised if flow batteries don’t turn out to be cheaper overall as far as meeting electricity demand over 24 hours is concerned.

      • Ross

        Yes, I was a little surprised at the certainty with which the Lenz blog stated power-to-gas would become the dominant storage technology in Germany.

      • Otis11

        Agreed. I see a system where 24 hour regular cycle plus a bit of a buffer are fulfilled by batteries, and then excess is used to make methane for long term storage or current batteries just aren’t suitable. (Heavy construction without charging infrastructure, airlines, off-grid backups, and long-haul trucking type situations.)

        • Russell

          Yes that sure seems like a likely scenario doesn’t it. Many countries will need seasonable storage with 100% renewable, and a process to turn electricity into usable hydrocarbons would certainly come in handy. I would expect that batteries will always be best for 24 hours, but impossible for seasonal of course.

          • Bob_Wallace

            I see no reason that we would need seasonal storage.

            If you look at the wind data on the Budischak paper (page 67) you’ll see that renewables produce electricity across all seasons.


            The exception might be to hold back hydro in the spring for summer use when demand is low and wind supply high.

          • Russell

            If say solar wipes the floor in terms of cost and production capacity because of a technology say like this (or just continues its exponential cost decrease)

            It would then be the cheapest form of electricity by far, even so for places with little sun in the winter. While other renewables may be capable of delivering, people will use the least cost option, which may be this kind of solar cell connected to a way to store the now very cheap electricity seasonally. If your rooftop solar panel supplied your needs 3/4 of the year, then with some kind of seasonal storage you could go completely offgrid. A bonus in many parts of the world where the grid isn’t reliable or is simply not there at all. This could also happen in a developed country grid “death spiral” scenario where the utilities do anything to make their money back, say very expensive winter electricity or a high flat connection fee.

            I can see such a thing happening soon in a place like AUS, where the utilitiy says, “Well you want to use the grid for 3 months during winter? You need to pay $1-2K per year to stay connected to our grid no matter how much or little you use and we don’t sell 3 month connections.”

          • Bob_Wallace

            Batteries cost money. Hydrogen tanks cost money. The cost of storing power for months would be extremely high.

            I’m getting ready to purchase a new set of lead-acid batteries that should hold about 3 days worth of electricity, and I use far less electricity per day than do most. Those batteries are going to cost me around $2,000. A week’s worth of electricity storage for most people could easily cost $10,000, a month’s worth could cost $40,000.

            Realistically the AUS utility companies are entitled to some level of compensation for what they provide. At the same time they won’t be able to unreasonably overcharge. Worst case, if things get totally out of control then the government will crack down.

          • Russell

            I agree that the scenario I am talking about is speculative, however I am not sure about your numbers. Yes the optimum scenario would be a rational power company, and that will probably happen, however it cannot be taken as a certainty in all parts of the world. I was specifically talking about a potential tech to convert electricity to hydrocarbon, not hydrogen and that wouldn’t cost anything like those prices to store. Gas tanks for 3 months don’t cost $40K even for hydrogen perhaps. I fully agree that 1 month battery storage will cost too much, I said that.

            Electricity to gas/hydrocarbon would even so have great benefit in some places as it would be cheaper than building power lines in many places. If you have a road, but no power line for 100K’s or so, then a truck delivering some cheap clean hydrocarbon made with renewable electricity could always be cheaper than building power lines and no less environmentally friendly (more so as it takes metal to build power lines)

          • Pete Stiles

            Bob, I’d like to know what batteries you are getting. I also have $2,000 invested for 14 x Trojan 105RE’s with a total theoretical capacity of 21KwH. I use about 25% each cycle (evening/night) but wouldn’t want to often push this past one cycle without recharge.

          • Pete Stiles

            In practice I just reduce consumption if it’s a poor sun day so the batteries will last 2 cycles without problem.

          • Bob_Wallace

            I’m shopping for T 105 REs. If you’ve got a good source please share.

            I don’t pull down that much over night, and seldom push through a sunless day without using the gen. It might happen if I’m away for a night or two.

          • Pete Stiles

            I got what I believe are unbeatable prices, paying just $130 each after core discounts (picked up locally so no shipping either). Ask to speak with Barb Duffy directly on; 888-826-0939 tell her I (Pete Stiles @ Sir Sparks Inc.) told you to call her.

          • Bob_Wallace

            Could you describe a country or two that would likely use seasonable storage rather than adjust their input mix to handle seasonal differences?

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