Redflow’s Hackett: We’re better than Tesla’s home battery storage


Simon Hackett, the executive chairman of Australian battery storage developer Redflow, declares himself to be the number one fan of Tesla electric vehicles in Australia. But he insists that Redflow’s battery storage product is better than the Tesla Powerwall.

Redflow threw down the gauntlet to its much-hyped international rival on Wednesday, announcing the release of the ZCell battery storage product, bigger and more expensive than Tesla and other big name products, but one Hackett expects to be a force in the market.

“As Tesla’s biggest fan in Australia I’ve got a view that they’ve got the best battery technology for cars, but we do a better technology for houses and that’s totally cool,” says Hackett, who has bought Tesla Roadsters and several Model S electric vehicles, has orders in for the Model X and will also be head of the queue for the new “mass market” Model 3.

“I expect Tesla to sell a hell of a lot of Powerwalls and the nice thing is that we have a market here that is going to explode, it’s not a matter of them having to lose for us to win or vice versa and you can appreciate as well we make a battery that’s a lot more grunt, a lot more capacity,” Hackett told RenewEconomy in an interview.

Hackett expects the market for battery storage in Australia to be “huge”. This, he says, will be driven by Australia’s high grid prices, its big rates of rooftop solar installation, a desire for more grid “independence”, and a wish to do something for the environment.

“I’m seeing the same set of signals from human beings that I saw at the start of the internet boom,” says Hackett, who made his fortune with his company.

“The batteries have gone from something that people that use to talk about in dark corridors to something that is a dinner table conversation in  households.

“Tesla are the catalyst here, not the cause. The cause is that the conditions are right, batteries are … starting to approach the cost where we can have these conversations.

“It’s a tipping point in my view , you can see it a year ago you couldn’t have this discussion with a random person about batteries, now every second person I talk to engages me about it.”

Redflow on Wednesday announced pricing details and specifications for its households battery storage system that it has dubbed the ZCell. The 10kWh battery storage system will be installed for between $A17,500 and $A19,500 a system. Redflow says that is competitive, on delivered energy and capacity, than its rivals.

On a back of an envelope calculation, if a household had the product for 10 years, and discharged it fully once a day, that translates into delivered cost of energy in the mid 40c/kWh. A lot for most households – although some, including low energy users, are being hit for that much because of high grid costs.

Hackett says initially the battery storage costs doesn’t matter so much. The market will be driven at this stage by early adopters, people who simply want to be part of it. Then, as costs come down, and they surely will – just like solar in the past decade – it will become a mass market product.

Hackett says the driver for battery storage is the same that inspired people to buy the Prius hybrid vehicle.

“There’s an inclusion point where people felt like they wanted to buy a car that was more part of the solution, and not part of the problem,” Hackett said.

“If you feel that the world is heading to a bad place in various ways, global warming etc, a battery in your house in the future won’t fix it. But for a lot of people I think its makes them feel that they’re becoming apart of the solution rather than continuing to contribute to the problem.

“If you’ve got a power station on your roof that you can keep energy in one of our batteries and you can charge your EV when you come home, now you’ve genuinely done something . You’ve actually created solar power transport.

“The combination of a solar battery on your house and mobile battery in your car lets humans make their transport fuel on their roof. Now that’s actually new.”

Hackett is not a supporter of the idea of going off-grid, although he admits people will do that because then can, and some will want to. For most, however, the grid will act as the cheapest form of back-up. It’s just a question of pricing that service.

“The question to ask is generally how often are people prepared to be without power, and often the answer is “I’m prepared to be without power”. If you’re in a metropolitan area and you don’t want to be the only house without power, then you need to stay on the grid or have some kind of back up generator.

“I think were getting into an era where there are pretty cool back up generators are turning up, like gas fuel cells. But the point is that you need to be budgeting for that if you want uninterrupted power, or you need to treat the grid like a leased gen-set.

“I agree that the grid operators don’t need to price themselves out of existence, but my strong view is that 5 years from now the smart ones will have realised they want battery storage operated to send power back when the grid needs it.

“We just have to get through this valley in the middle where the perception is that they’re anti battery.”

Hackett, however, describes the idea of “vehicle-to-grid” – using EVs to power up the house as a “bit of a furphy”.

That’s because he believes that the cost of battery storage will fall to such an extent that it will no longer be a question of having battery A or Battery B, but having both.

So why buy a flow battery?

Hackett says: It’s bigger, it’s better suited to a heavy workload than lithium-ion batteries, it doesn’t need active cooling, and it’s local. “It’s designed in Australia for Australian conditions,” he says.

To read more about the Redflow ZCell battery launch, read our story on our sister site One Step Off The Grid.


44 responses to “Redflow’s Hackett: We’re better than Tesla’s home battery storage”

  1. Mark Diesendorf Avatar
    Mark Diesendorf

    For Simon Hackett: The ZCell sounds exciting and I look forward to learning more about it. However, as a flow battery, doesn’t it consume power even when it is not being charged or discharged? If so, what is this standing power use?

    1. Simon Hackett Avatar
      Simon Hackett

      Hello Mark.

      Actually, the standing power usage is very small. See this FAQ to explain why:

      You may also find this interesting – something we call Hibernation Mode – which is a full shutdown (with all charged energy retained). Its not what you meant, but it is a very cool thing indeed for certain ‘intermittent use’ off-grid sites or emergency backup applications, and its unique to our battery:

      1. Ron Horgan Avatar
        Ron Horgan

        Simon, I am concerned about the toxic potential of free bromine.
        I understand that the electrolyte is of low toxicity and unlikely to catch fire or explode as is the case with some lithium batteries.
        However under what conditions will thermal exposure release free bromine? That is if the battery, house , factory etc catches fire ,( even a high intensity bush fire) surely free bromine will be liberated?
        If so this may become an unacceptable health and insurance risk.
        Sorry to ask such an elementary question , but I would not use your device without some evidence as to the safety under such adverse conditions.

        1. Ron Horgan Avatar
          Ron Horgan

          I have asked this question several times and as yet no response.
          This silence is significant.

  2. solarguy Avatar

    Wow $17.5-19.5k for a 10kwh battery. Can’t see too many being sold initially.

    1. Andrew Avatar

      This is the expected total price including battery + inverter + Installation $ for $ output for output – equivalent to other batteries in the market!

      1. solarguy Avatar

        I can do the same for about $15-16k with Lifpo4 storage.

        1. Andrew Avatar

          with 100% DOD and 10kWh output from day one for a minimum of 10 years? – no reduction in capacity during the 10 years?

          1. solarguy Avatar

            No 80%, but will last as long.

          2. Andrew Avatar

            cool – so that makes them the same $ – Reflow 100% DOD = $17.5 – $19.5
            Lifpo4 $15-$16 @ 80% capacity.

            I’d be interested to see the guarantee on the specs of performance over time – i.e. the output in kWhs @ 10 years.

            I understand the Reflow battery has a 30MWh warranty!

          3. solarguy Avatar

            Ah,no the Lifpo4 is cheaper for the same capacity and yes Redflow has 30MWh warranty. I’ll know more latter.

            Forgot to mention good lead acid gel deep cycle VRLA batteries are cheaper still and perform better and longer if designed correctly for the application (DOD) and give over 4500cycles.

          4. Alistair Spong Avatar
            Alistair Spong

            Is that lifepo4 are cheaper @ 80% and then including the degredation of the cells over 10 years to 80% capacity ?

            The thing with the redflow is its not degrading , but what happens after 10 years or the 30mwh warranty , does it fall off a cliff and not work at all ?

          5. solarguy Avatar

            80% DOD is the best for long cycle life in respect to the fact @ 90% will have less cycle life. Having said that, a shallower DOD does increase life even further. A battery is usually ready for replacement when only 85% of its capacity can be tapped.
            The thing with Redflow’s battery as far as I know is that the electrode stack wears out and perhaps the membrane and pump need to be replaced. I don’t know how quick it degrades after warranty period.
            Look if your after better bang for your buck with batteries, BAE deep cycle gels, properly sized for your application can last 10yrs or more and give more power for those short peak demand periods. All for a cheaper price than flow or Lithium. Lead acid tech has been around for over 100yrs and is a well known, tried and tested battery.

            At this stage I’m planning to use BAE’s for my system later this year as I have confidence in a 100yr old technology that is well understood. It will take a lot to change my mind!

    2. Roger Brown Avatar
      Roger Brown

      You forgot the ” installed ” part of the sentence . Would that also include a “inverter ” or whatever they call them connected to a battery system ?

      1. solarguy Avatar

        see post below all included.

  3. Paul Avatar

    The only part I really disagree with is that the Grid will be the cheapest form of backup. yes it’s probably the easiest or laziest option available at present.
    We already pay $420+ (QLD) per annum to be just connected, if we continue to see the increases in connection and service fees , a decent complete Off-grid install or just a Generator may be a cheaper option sooner rather than later.
    I also disagree that people that have or will install a battery Storage system , are going to willingly give away their energy to the utility without being fairly compensated for both the Energy and the Service they now provide and also the cycle life reduction that the utility now uses from your Asset rather than theirs.
    A kw from a Battery storage system is far more valuable than one from a Solar install only. I look forward to the reports and arguments that will follow about the value of stored Energy and Grid stabilization and FIT’s with reference to the battery system etc etc.

    1. Steve M Avatar

      Agreed!! the utilities are pushing for grid defection with these charges. Battery manufacturers are off the mark and need to consider 16kWh batteries and be able to be full off grid to make serious inroads. If Redflow produced a 16Kwh battery for $16,000 they would be in with a chance otherwise unfortunately they have missed the market.

      1. Mike Dill Avatar
        Mike Dill

        With Pb at US$200/kWh and Li at US$400/kWh Redflow needs to get the battery price in that ballpark. Yes you need to add a few $$ for the inverter/charger and control electronics, but $A17500 for a 10kWh battery system is really outside of the park.

        Yes some early adopters will go for that, but a 80% DOD Li system to get you the same capacity is very close or possibly lower in price. Come on Simon, you can do better than this.

        1. Simon Hackett Avatar
          Simon Hackett

          Our cost per kWh will reduce over time, as for other battery technologies.

          Meantime, we have technical features unique in the market that provide some use cases that can’t be matched with other batteries at all.

          Small example of the latter being this:

          Also, and as a more general statement – the lifetime of other battery technologies is inversely related to how much you actually cycle the batteries. Use Li or VRLA hard, and you’re shortening its life. Don’t use it hard and you’re not really working your investment. Our battery thrives on daily 100.0% deep cycling (and genuinely 100%, no reserved capacity).

          Our output capacity also doesn’t have the same degradation curve in output capacity with age that the other types have.

          See our FAQ at under “Technology’ for more discussion around these points.

          1. neroden Avatar

            I wish you luck. It’s gonna be a difficult market, like solar panels are, with heavy price competition and tech improvements every year. But best of luck to anyone working in it, because we need all the cheap, powerful, long-lasting, nontoxic batteries we can get!

          2. Brendan Lee Avatar
            Brendan Lee

            Hi Simon,
            Do you have plans to release a battery with a larger tank, but using the same converter (e.g. same power, more energy?)

          3. Ken Fabian Avatar
            Ken Fabian

            Simon – it seems more likely any battery I have installed will only rarely reach 100% DOD and more likely have mostly shallow cycles – if Zcell thrives on deep cycling, does that mean it is bad for it to have mostly shallow charge/recharge cycles? Or will the total MWhr throughput life expectancy mean less DOD results in significantly longer life? And can the battery be reconditioned rather than replaced to extend it’s working life?

            I’ll be weighing up my options ahead of NSW FIT scheme expiry but expect to increase the PV side and potentially include batteries. Grid connected is my preference but if the fixed costs keep going up I may choose otherwise – oversizing the PV and managing demand during extended overcast conditions would probably be very feasible in my case as an alternative to a backup generator.

            One of the things that make flow batteries attractive is the potential to oversize the storage compared to the charge/discharge rates. Even, potentially, we could be able to have a delivery service that can swap-out fully charged electrolytes for disharged if we miscalculate our usage.

          4. Alastair Leith Avatar
            Alastair Leith

            Disruptive tech does better features *and* at a significantly lower cost. Saying ‘we’re better’ needs stronger justification from the point of view of buyers.

        2. Thomas Brady Avatar
          Thomas Brady

          Good luck with 80% DOD ON Li in Australian conditions, last I saw a reputable company was using 50%

      2. Simon Hackett Avatar
        Simon Hackett

        Hardly. The market is only barely beginning.

        1. Stewart Lamond Avatar
          Stewart Lamond

          Simon, 10kwh does seem a bit low if one is in a remote area completely off grid or trying to use the grid to the absolute minimum. Do you have to string more flow batteries together to get a bigger capacity (and thus pay considerably more)? Perhaps you are planning a higher capacity battery later?

      3. Anders tn Avatar
        Anders tn

        This is basically what I as a Norwegian feel as well. With the cost of batteries coming in at a 1$ to 1kWh price point or slightly cheaper it would be an advantage to a generator on any cabin in Norway. Now all we needed was a cheap small windmill to fuel it. Solar is pretty much useless up here during the winter months.

    2. solarguy Avatar

      Certainly hard to disagree Paul.

    3. Thomas Brady Avatar
      Thomas Brady

      Your right this product is not even launched yet and they are talking about 100c/kWh for power from batteries during grid events.

  4. Rob G Avatar
    Rob G

    The understanding of human nature, to want to be part of the solution is a very significant point. This coupled with the desire to produce and be independent make batteries very attractive. Meanwhile our government looks to constantly undermine our renewables and push the coal case – sending a message out to voter land that they don’t want to be part of the solution. Solar and battery owners are seeing this dividing line clearly now and it will eventually hurt them at the ballot box.

  5. Brad Sherman Avatar
    Brad Sherman

    Simon, How is Redflow dealing with end-of-life disposal of the batteries? Last time I checked (some time ago) it had to be handled as hazardous waste because of the Br. Is this still the case?

    1. Roger Brown Avatar
      Roger Brown

      They are 100% recyclable , It can’t catch fire or explode as the electrolyte is a natural fire retardant and is low toxicity.

      1. Brad Sherman Avatar
        Brad Sherman

        Is the infrastructure set up (or being set up) to facilitate the recycling? From what I understand Redflow will take the batteries back at end of life and recycle them as much as possible. I guess my question is that because the electrolyte can only be disposed of by licensed chemical handling companies does this mean that special provision needs to be made to send the batteries back to Redflow for disposal.

        I guess my ultimate question is for any battery technology: what is the full cost of ownership from acquisition to installation to disposal in compliance with all existing regulations. I suspect they can’t simply be sent to the tip at the end-of-life.

        My limited understanding is that bromide is benign and bromine is potentially dangerous and that the electrolyte in these batteries converts between the two forms. Presumably the bromine is sufficiently bound to some other compound that in the very unlikely event of a spill it won’t present a significant health hazard. I’d appreciate information that clarifies this.

        1. Roger Brown Avatar
          Roger Brown

          When you find out , get back to me . I have no connection to Redflow , just what I read on the Redflow stories.

          1. hydrophilia Avatar

            In flow batteries, the reaction area is not the same as the electrolyte storage area, so the folks who service it would bring you new bits and take away the old bits. The shipments would be two directional (even the same shipping containers?) rather than being our usual mine>refinery>manufacturer>shipper>installer>user>landfill one could return whichever needed to be recycled. I would bet on the same shippers taking old electrolyte or machines so their trucks do not ever make the trip empty.

            It is hard, however, to compare costs when Tesla quotes their equipment barebones and requiring installation and Redflow quotes a finished installation… Time will tell, but I love seeing so many hopeful developments.

        2. Ron Horgan Avatar
          Ron Horgan

          Me Too Brad.

  6. JeffJL Avatar

    “On a back of an envelope calculation, if a household had the product for
    10 years, and discharged it fully once a day, that translates into
    delivered cost of energy in the mid 40c/kWh. A lot for most households –
    although some, including low energy users, are being hit for that much
    because of high grid costs.”

    FFS. If it is fully discharging once a day that means that they are using 10kWh during the night. Let us be generous and say they use the same during the day (while they are not sleeping), thus usage is 20kWh/day. Not a low energy user. So why quote the 40c/kWh in the same paragraph.

    I love the idea and think the technology behind it is great but some honesty in advertising please.

    1. Paul Avatar

      JeffJl – we are already paying roughly $0.30c per kW (QLD T11) inclusive of service fee , in 10 years , with even modest 10% increases per annum , we will be paying $0.78c per kw.
      The difficult part of all this is that no one has a crystal ball and technology will advance , utilities will change their pricing models to adapt to the Grid defection that will happen to some extent , system pricing will increase with compliance , yet the batteries will come down , incentives will come inot plan at some stage also , so It’s got to start somewhere.

      1. JeffJL Avatar

        I am a great supporter of battery storage and solar PV. To me it is the best way to remove the afternoon peaks that occur in many of the worlds power grids thus requiring less upgrading of the grid and fewer peaking power plants.

        I just think that quoting 40c/kWh and low energy users in the same paragraph is misleading.

        I will definitely be looking at this product in a few years when my FIT expires.

  7. Giles Parkinson Avatar
    Giles Parkinson


  8. DJR96 Avatar

    OK. Recycled article from March.

    I wonder how well the figures stack up now with the Powerwall 2 released?

    Quite frankly the prices are outrageous. I get it that they’re relying on “early adopters”, but that is hardly commercially credible.
    Sure there is a fair chunk of R&D to be recovered (which was probably covered by govt grants), but the physical manufactured cost of these units should be a fraction of what’s listed. Sorry, I just see this as price gouging and poor value for money.

  9. ROBwithaB Avatar

    Prices seem a bit high, to be honest…

  10. Diego Matter Avatar
    Diego Matter

    They were better than Tesla’s home battery storage. Not anymore with the advent of the Tesla Powerwall 2.

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