Are Flow Batteries About to Take Over? A Lab Tour of RedFlow's Zinc Bromine Battery

Join me on this project tour of Redflow's hybrid flow battery facility in Brisbane, Australia.
Energy storage is a huge topic these days as electricity grids are seeing larger and larger proportions coming from variable renewable sources like wind and solar and storage is used to fill the gaps between variable supply and demand. Traditionally, nearly all storage in the electricity grid came through hydroelectric dams, but in recent years the new storage capacity that’s been added has been overwhelmingly lithium-ion batteries. This has occurred in tandem with EVs and their lithium ion batteries also experiencing exponential growth. But if this exponential trend is going to continue, there will be supply chain problems to overcome as there aren’t yet enough mines for several key minerals, like lithium, to fill all the projected demand over coming decades. This is one of the number one objections that I hear from climate pessimists: we don’t have enough critical minerals to make enough lithium ion batteries to support a 100% renewable electricity grid. Now, those arguments are misleading for several reasons, but the main one is that lithium ion batteries aren’t the only electricity storage technology available.
Lithium ion batteries are incredibly appealing for EV applications because they can pack a lot of energy into a small and light package. But for stationary storage, the size and weight don’t really matter. What does matter is cost, especially for longer storage durations of ten hours and more. That’s something that li-ion batteries don’t do particularly well. To double the storage duration of a lithium ion battery you pretty much need to double the cost.
That is not the case for flow batteries, which is the topic of today’s video.
Flow batteries are a type of rechargeable battery that use two chemical components dissolved in liquid electrolyte. The electrolyte is stored in external tanks and pumped through a reaction chamber to produce electricity. The key thing about flow batteries is that is cheap to increase the storage duration, much cheaper than for lithium ion batteries - I’ll explain why later on.
Last year while I was in Brisbane I had a chance to tour a hybrid flow battery manufacturer, Redflow.
In this video we’re going to look at how their batteries work, how they’re tested and how their design has evolved over the years.
I was keen to visit Redflow because while the hype around flow batteries is a pretty recent thing, these guys are no spring chickens. They kicked off pilot studies back in 2010 and by now there are Redflow batteries in over 250 sites. Originally they were just selling single 10kWh batteries for residential and remote sites, for example for communications. And these days they are looking at large modular systems in the tens to hundreds of MWh.
Bookmarks
00:00 Intro
00:50 Redflow
01:12 How does a hybrid flow battery work?
02:10 Anatomy of a Redflow Battery
03:49 Pure vs Hybrid Flow Batteries
04:48 Redflow’s Technology Development
06:26 Recyclability of Redflow’s Batteries
07:15 Applications and Scale Up Plans
09:19 Latest updates from Redflow
09:47 Outro
The Engineering with Rosie team is:
Rosemary Barnes: presenter, producer, writer
Kevin Irman: research, calculations, assistant editor
Javi Diez: editor www.linkedin.com/in/javierdie...
If you would like to help develop the Engineering with Rosie channel, you could consider joining the Patreon community, where there is a chat community (and Patreon-only Discord server) about topics covered in the videos and suggestions for future videos and production quality improvements. / engineeringwithrosie
Or for a one-off contribution you can support by buying a coffee ☕️ here -
www.buymeacoffee.com/engwithr...

[@outcastoffoolgara]

I am very pleased to see RedFlow still going strong and expanding their product capability. These are mighty good systems from their beginning through to now.

[@dprcontracting6299]

That was fantastic Rosie! Those guys have really got industrial production experience that is so heartening for us punters to see

[@ElectricCarAustralia]

Great video. Given these guys are based in my part of the world in Brissey hoping to also do an interview with them soon. Keet up the great advocacy and education work Rosie. Great to see you hosting at FCL in March. 👍

[@moony2703]

If you do could you ask about pairing a flow battery with a lithium for residential use compared to just flow or just lithium, please? Also the rough price for residential use if they are willing. It would be interesting to see where they are on the cost curve vs lithium, perhaps even compare the old flow battery price vs the current flow battery price if anyone can get it.

[@ElectricCarAustralia]

@@moony2703 will do! From what I hear they are more expensive than lithium but what % don't know.

[@BillMSmith]

Thanks Rosie. This is the sort of stuff I rely on you for. I'm pleased to see that there are actual long(ish) installations from this company, that's exactly what we need to see to encourage the more timid folks that energy storage with renewables is viable. But you did open the video by dashing my hopes for becoming rich by cornering the market for lemon batteries. 😞 Well, on to the potatoes...

[@gregvanpaassen]

Great video, and I wish RedFlow every success! Great to see some flow batteries "in the flesh". I'm a little surprised that some batteries are being retired already. The conventional wisdom is that for this application application a 30 year life is required. Particularly for roles in distribution networks.

[@allanhugh2044]

This is the first time I have seen someone reviewing a Redflow battery that actually explained it properly and correctly; although I did have to stop, go back, then slow down the replay in the part where you were discussing the charging and discharging through the membrane. I needed to switch on subtitles as I couldn't hear what the lady was saying when she was showing the plates and membrane. You are pretty much spot on with everything. I was surprised that you didn't mention the red colour of the hand held vials of solution; essentially it is where the name Redflow comes from. I have two of these batteries, which are now 3½ years old and still going strong.

[@outtolunch88]

I started following these guys about 15 years ago - and I'm still waiting for a commercially available domestic model.

[@jjamespacbell]

Another form of "Tesla Killer" while Tesla started battery storage just a few years ago and has hundreds of major sites installed and running across the world. I wonder if that has anything to do with the customers doing the math and concluding total cost of energy storage is superior in a MegaPack?

[@shiraz1736]

I’m pretty sure you can, I guess it depends what country your in maybe.

[@Alrukitaf]

@@shiraz1736maybe check out their installation in California. According to Rosie, they completed it in December’22

[@Theballonist]

@@jjamespacbell flow batteries are, from a physics perspective, less metal enriched per kilowatt of storage. The technology will ultimately be “cheaper” both in financial and real terms. Tesla batteries are going to have much higher recycling costs at end of life because of all the metals that have to be extracted safely but in high volume. That is an “externality” to their business model, but it is also a huge amount of value that they are leaving on the table at the same time.

[@MichaelPickles]

Unless its cheaper than lithium iron conventional batteries. And readily available. It's not going anywhere.

[@royharkins7066]

Wow I’d love a totally transparent version ….it’d make better watching than most tv programs 😊

[@avidian888]

Thank you for showing us the in-depth interviews and scientific steps behind new developments, it’s far more interesting than super hyped up new tech that will never see the light of the day.

[@snoopaka]

Another fantastic video! I am sure you are staying very busy in between videos. Glad you covered an existing technology that is already out in the field!

[@mikeklein4949]

Hugely encouraging news Rosie. Thank you. There seem to be new horizons popping up constantly, new types of technology such as flow versus lithium-ion, but I suspect there are new narrower horizons popping up within these broader development and implementation horizons.

[@johnransom1146]

Love the content. I can follow your conversation but it is getting faster.

[@SuperFredAZ]

Very interesting. Thanks for the even-handed presentation.

[@Fomites]

I've been interested in Red Flow since I first heard about them in 2010 but this is the first time I've seen the equipment. Great video! Thank you :-)

[@philgoogle1535]

I'm a long suffering Redflow shareholder. I believe in the technology and its potential but frustrated as to why our energy companies (and government) don't see this. RFX has had some recent success in the US but I'd love to see its own country embrace it.

[@mrtmat]

This is fascinating and very exciting. efficient storage solutions are so important to an energy transition.

[@LoanwordEggcorn]

Thanks for good coverage!

[@moony2703]

Awesome to get an update on these guys, heard about them years ago and it's great to hear how much they've scaled up. Also awesome to hear they are active in the residential space. I wonder how a flow battery paired with a lithium battery would go vs just a flow or just lithium for residential use considering how some people are already using two lithium batteries on their homes.

[@shiraz1736]

Lithium batteries are wasted in a residential application , these batteries are well suited to residential needs.

[@bimblinghill]

I'm often sceptical about new tech ideas, but this seems like a winner

[@MartinMenge]

I bet these will become increasingly common in South Africa. Every housing estate, private industrial park, mine, farm and mall will probably have one within a decade.

[@EcoHouseThailand]

RedFlow's Zinc Bromine Batteries are manufactured here in Thailand. A few years back the reseller here quoted me US$16,000/AUS$24,000 for a 10kWh ZBM2. I am hoping that the prices will fall as production scales. I ended up paying AUS$3,000/US$2,000 for equivalent sized LFP batteries.

[@tlangdon12]

The prices will fall as they scale up their production, and figure out how to supply the residential market without incurring significant additional costs.

[@worskaas]

​@@tlangdon12I'm beginning to think it won't make sense for residential, due to the battery requiring a maintenance contract in place for regular maintenance checks. Ideal to create jobs but unfortunately for residential use, money doesn't grow on trees.

[@tlangdon12]

@@worskaas I'm not aware of the needing maintenance checks on a regular basis. They just need repairing when they go wrong.

[@SirHackaL0t.]

It’s so good to find a product that’s lived up to the hype.

[@zaneenaz4962]

Nice video compilation of knowledge and facts. lifespan amd/or maintenance costs would be interesting to know. imagine the startup process is not trivial.

[@adam872]

Enjoyed that. One of the reasons I've been a bit skeptical of a complete renewables path is the question of energy storage and how battery systems can be built at scale. These systems seem to be a reasonable option at a facility level and in my line of work (dealing a lot with remote mining installation OT environments) they would be pretty viable. I wonder if we'll start to see more grid scale applications of this tech?

[@chrisb508]

There is so much talk about lithium based batteries and other batteries that are the going to revolutionize the industry. I love seeing a reasonable alternative that has been built to scale and isn't just "what could be".

[@geordiew2162]

Great Discovery Vid, Awesome feel.

[@KevinLyda]

I live in Ireland and have residential solar. It varies from 1 kWh per day in winter to as much as 45 kWh a day in summer. I've been looking into microwind generation to supplement it, but it's clear that needs storage to work. Flow batteries have looked really tempting as a solution (sorry) for years now. As I'm in a rural area, space isn't as much of an issue. So for me, the smaller footprint of hybrid flow batteries doesn't overcome their lack of cheap expansion options. The more I learn about wind and solar generation, the clearer it is that we need storage systems that can handle large spikes in generation and can store power over the span of weeks. On the flip side, EV hub charging stations on motorways or fleet depots need to handle large spikes in demand for short periods and then produce very little for much of the rest of the time. Which seems like a great use case for storage as well. The traditional grid wasn't really designed for this. My car can draw the full power needs of over a dozen houses - for about 10 minutes. A strong wind will blow for a day or two and then very little for a week where i live. Flow batteries look interesting though the moving parts give me reliability worries.

[@brianjonker510]

Yours is an interesting experience. I suspect those moving parts in the flow battery are off the shelf parts and assemblies that have been proven durable in other industries for decades.

[@brushlessmotoring]

I'm curious if compressed air is a reasonable place to start as you have the land.

[@tlangdon12]

These flow batteries should be ideal in your application, but Redflow are not focused on the residential market yet. Their focus is on grid-scale applications, and it is there where the money exists to improve the product to the point where residential customers will be able to buy them and be happy with the. The moving parts should be source of concern - in a grid-scale implementation there is enough redundancy for the failure of a single battery to be of no conseqence, but if the pump fails in a residential application, you are stuck; neither being able to charge nor draw on the power stored in your battery. Perhaps Redflow will develop a high-avalability version of their product with a redundant or hot-swap pump, or perhaps a solid-state pump will become available.

[@roddehoedt8254]

Redflow has just announced a 20 megawatt 2,000 Battery project to be installed in California. It seems America has recognised how good the Redflow Batteries are. I am surprised that we don't see more interest and support for these in Australia. Plus I believe Redflow Batteries are fully recyclable, do not need lithium and other metals essential to Lithium Ion Batteries, which will become more expensive as Electric Vehicles take off. For stationary installations like the one just announced in California, Redflow seems a much better choice. I also read that Redflow Batteries do not pose any fire risk danger, as can be the case with Lithium Ion. Fire in a large multi battery installation of Lithium Batteries, must or should be a concern for Companies or Individuals considering the options. It would be great to see you do an update on how the completed 2 megawatt California project is performing.

[@tonydeveyra4611]

I think the niche for flow batteries will be long term seasonal energy storage.

[@saddle1940]

I'm concerned about the high failure rate displayed by these batteries during the Canberra Tests. Very high failure rates were displayed in those tests by many battery types (not good all round). They were replaced three or four times due to contamination (once) and leaks. Leaking fluids in flow batteries was my first thought as the pumps have to run constantly long term pushing reactive chemicals for the scheme to work. Pumps like that should probably be inside the tank where leaks don't/wont matter (probably already are, hard to tell from the current info).

[@petewright4640]

Would be good if Rosie compared Redflow to other flow battery types such a vanadium and iron.

[@daveeff-subs846]

Good stuff! Thanks.

[@mickgatz214]

This video batterified me completly!

[@mikeda3643]

Followed Redflow since Simon Hackett invested. Biggest issue is cost per KW when comparing to LiFepo4. There is also the need of the constant maintenance period for the zinc to be flushed (may have changed). As someone who lives off grid, and currently looking at replacing my 57kw Gel setup lithium is still the only reasonable choice for now for residential users.

[@gedw99]

The 160 would suit . 1 of the 4 is automatically taken offline for a full zinc recalibration while the other 3 take the losd. It’s 50 to 60 k installed and that includes everything . Inverters etc etc.

[@spiderbite7849]

You can improve your video quality in the lab by setting the shutter speed to a factor of 50, due to the 50hz lighting. So 1/100, 1/150, 1/200 etc. Also you could invest in dual clip on wireless lapels like the Rode Video Wireless Go II, or the DJI Mic.

[@venjsystems]

Great stuff Rosie, keep up the good work.

[@Hybridog]

These batteries could be very useful in expanding fast EV charging stations in areas where grid stability or high current service is an issue. Freewire has charge stations with built in batteries that allow you to get installed quicky and easily to a standard voltage and current power service. No special high capacity service needed, no long waiting periods either. You could achieve the same result by installing a couple Redflow Quadpods along with a standard charging station. The batteries get charged at night when power is cheap and plentiful, and then kick in during the day as needed to make up capacity as cars are charging. No worries about overloading the grid and maybe even car charging when the power is out.

[@showme360]

As soon as I set eyes on the Redflow Battery design 3 - 4 years ago I wanted one for my house as a 20kWh battery bank, but unfortunitly they where not shipping them to the UK. So I am stuck with lithium, but as soon as I hear Redflow are selling here I will be after a couple of units. I belong to a Co-op that supplies solar to local schools and I believe this system would be perfect for this application because of teh safety aspect. So when ever your ready Redflow we will be asking for a shipping container full of your type ZBM 3 units!

[@thecuriouslobster]

Cool channel Rosie! Hi from the UK 👋

[@thomasculshaw8843]

I love the idea of a battery with no toxic component

[@54mgtf22]

Hey Rosie. Love your work 👍

[@ChristianMaskrey]

Rosie you rock !! Thanks for all the great explanations!

[@Jawst]

5:21 this is how I like to grow my tomato plants 😆 when you do lots of tests with lots of variations it's very easy to spot benefits in processes and products

[@en2oh]

Great video, Rosie! Definitely a new subscriber! On another note, do you happen to have a video on riveting? :) Ok on a serious note, did you get any idea of how they have overcome shunt currents with their system?

[@khushwantmistry1031]

Nice Knowledgeable video 👍🏻🙏🏻

[@julieta203]

Its great to see Redflow progressing and making traction to develop their product. But they really need to hire some skilled industrial designers to improve their product look and feel which can also save a lot of money in mass production. Their branding needs to be improved too it all makes a huge difference in todays hi tech world.

[@AnaZet-Solar-Energy]

Quite interesting, Lets see how such technology develops

[@reblackened]

Hi Rosie. I've only just subscribed to your channel after hearing you on Dr Karl's podcast. Looks like I have some catching up to do! Great work on the channel as a whole. I'm curious to know what the best use case is for these batteries? Why this type rather than another? Apologies if I missed the explanation within the video.

[@stephenbrickwood1602]

Love your work.

[@michaeldepodesta001]

Rosie, Thank you for another interesting video. Do you have information about cost and energy density. The Quad Pod looked a bit bigger than 3 Powerwalls, but perhaps it is much cheaper? All the best Michael

[@Istandby666]

Longer storage duration is not just from larger tanks, but also the difference in chemicals used.

[@LeftCoastStephen]

Very interesting technology. I especially like the ability for the charge to go to 0. The high temp tolerance is great for Australia but what is the low temp behaviour? I’m interested in off grid wilderness cabin application in the mountains of western Canada. The cabin is used intermittently through the winter with temps typically -10C but can get colder. Lithium doesn’t like cold and most of the energy would be used keeping warm. Lead acid would work but if less than fully charged, not so much.

[@quartamile]

Just looked at their website. Couldn't find pricing, anyone know? Also, the site says they cannot operate below 50°F, that's not good; maybe they're only intended for equatorial regions?

[@stopscammingman]

Many countries need an awful lot of these.

[@puffinjuice]

Excellent video!

[@tommclean7410]

Sounds like very promising storage technology. I may have missed it, but cost was not mentioned. My understanding is that Li-ion batteries are about the same price but tend to degrade over the years. If used for long(er) term storage, like pumped hydro and CAE, then hybrid flow batteries would seem to win if $/kWh is a little higher because they are faster to deploy and modular (so can be scaled up over time as needed). I especially like the use of non-toxic chemicals and the promised of 100% recycling. Thanks for another informative video!

[@yesgogood7304]

I think Redflow advantage is heat resistance, non flammable, deep / full release. But I think the round trip efficiency is not as good as Lion/Sodium, I am not sure, but I think in Max their battery have around trip efficiency in the 80s while Lion and Sodium is at the 90s. Just based on Google, I think pumped hydro is around 100USD (if this is really the case, please someone confirm it for me) CATL said that their 1st gen Sodium Battery is 77USD/KwH and 2nd gen is 40USD/KwH and that is 2025/6 (est), remember building a pump hydro is 10 years of planning + Construction, I am so afraid that even pump hydro is 40 USD / KwH as an accountant I will tell you I still opt for the Sodium option (even 35 USD/KwH), although I know that you never needed to replace a pump hydro station. 1) pump hydro is not necessary carbon free, there is a study from EDF (they are not independent they are nuclear) but there is a theory that pump hydro will release methane (Biodegradation). 2) the geo area is restricted and if you are not looking to storage water as the main goal, you still needed to have long cable to connect to the grid while battery can be right next to the grid. 3) I can price battery in small localized location, that can act as a bundle of micro grid connected to a big grid, while I don't needed to have a huge cable to transmit electricity. e.g. I have a very density area, I place a battery into it, normally I know that there is a lot of roof top solar to feed into this local battery, but in case it is raining for days, then I can pump electricity slowly and constantly and rely on the battery to discharge and recharge (at night when sleeping) so you don't needed to upgrade the connection that much.

[@cg986]

Amazing! I think Vanadium Redox Flow Batteries also have a big potential.

[@rw-xf4cb]

Vanadium is used in some metals manufacturing from what I heard so there's competition for it. Also its toxic (wwwn.cdc.gov/TSP/substances/ToxSubstance.aspx?toxid=50) and availability is lower than zinc and bromine (ocean has heap of it)

[@MinusMedley]

I really want some, that 40kWh cabinet would be great for residential.

[@SimonSonderskov]

Nice video Rosie, thanks. Do you know of the battery technology developed by Eos Energy? Presumably also Zinc-based and for long duration storage applications. But, as I understand, not a flow battery. Would love a video on that :D

[@alanblyde8502]

Luv ya work Rosie👌🇦🇺

[@markthomasson5077]

I suspect there is a lot of hand building in these units, whereas normal batteries are highly mechanised. So will they be able to mechanise the production and get cost down?

[@incognitotorpedo42]

What IS the cost per kWh, BTW?

[@zaphodbeeblebrox1130]

super awesome !!

[@fredericrike5974]

You didn't mention it, but is there any chance this will be produced as a residential use battery? Awesome follow up, Rosie!

[@-LightningRod-]

Rosie is Great and Redflow is legend

[@dino5002]

Interesting video thanks. Its really missing the cost analysis to know if this is a viable alternative to lithium.

[@Altrovexrecords]

Hi, thank you so much Rosie, for your interresting coment and video about fluid based batteries... Using Vanadium have no potential for Flow batteries...

[@Petch85]

I like the redflow battery idea. It looks to me that they could ise thinfilm technology to mass produce the battery thereby reducing the cost. Even just 1 of these batteries would be grate if you had solar on the roof. If would be grate if it could charge with 7-10kW, but a discharge of just 4kW would probably be ok except for charging a car. 10kWh would be ok for many houses, but if you have a electric car you would probably need a lot more. But if the battery's were mass-produced and they where modular and you could just add one more to you system your self after having the first one installed I could really see this in many houses. If you could just bay them in the hardware store or order on online like it was no big deal.

[@davidwilkie9551]

As a very knowledgeable Engineer, are we ready for the overhaul of our Australian Government system of law making and management. Would be good to put Alan Fels on the job of getting back to a system that actually stops the looting.

[@NickDDDD]

HI - great video thanks. Am interested in Grid Scale Storage. Why aren't these just super scaled everywhere (excuse the naivety of my question!). Thanks vm.

[@rpaulwaddington1858]

Thanks for great video Rossie. Do you know what has happened to UNINSW Vanadium redox flow battery technology. I understood it to be a more cost effective, safer, more reusable tachnology?

[@worskaas]

How do they determine the difference between residential and commercial use? Is it contract based, VDC of 900, space occupied, or safety standards for commercial vs residential?

[@MartinMenge]

Any updates on the virtual power plant they were going to construct in South Africa?

[@hubhubmei7174]

Really good video and product. I used to work on this topic and found the toxicity of Br2 very challenging. I am surprised they managed to correct this default 🤔

[@rogerlette]

Look at Kemiwatt, a french company which is n'ont using Br2 but degradable and non toxic elements (quinone).

[@steveyountz1757]

Hmmmm........Wouldn't that Shure mic work better if it were plugged in? Just found your channel and think you did a very nice job.

[@dc1544]

that is huge. I have 60kw Lifep04 and it takes about 1/5th the space maybe less. I do like seeing different storage solutions for energy.

[@tlangdon12]

LiFePo4 batteries are very energy dense. These flow batteries are never going to get small enough or light enough to be used for mobile or portable systems, but for applications where space is not at a premium, they can offer a useful cost savings as they don't rely on any rare elements. Static applications is where they will excel.

[@odizzido]

It's nice to see one that looks like it's actually happening. Also that battery at 7:35 isn't too huge, you could easily fit multiple units in a typical garage in Canada...though looking at their data sheet the operating temperature is between 10-45 degrees so it would need to be installed indoors here. That could be somewhat challenging since it's 1500kg so you would need to be determined to actually get this thing inside. I don't see any info on pricing? Also how many years or discharge/recharge cycles can it handle?

[@gedw99]

Cost benefit summary against traditional lifo would be good

[@tangerinestorm]

Great video but unless these are cheaper than LFP or have a significant advantage over them I can't see it being terrible useful. I always thought flow batteries woudl be great to replace petrol station as they already have massive tanks and it would be minimal cost to dig then up and replace with a flow battery that can be charge with cheap energy overnight when demand is low.

[@thesparetimephysicist9462]

Nice video Rosie. Can you maybe go into more detail with the benefits of this type of battery? Why is it an interesting technology when compared with Li-ion or compressed air?

[@nc3826]

cost effective scalability

[@thesparetimephysicist9462]

@@nc3826 Thanks. Would be nice to see some numbers.

[@nc3826]

​@@thesparetimephysicist9462 Ironically, I watched a post In the last week comparing the three commercially available types of flow batteries.... So the data is available.... Good luck taking the time to find it...

[@chuxxsss]

Victron inverter, love them.

[@jollie1989]

Nice! Do they have any projections for cost/kwh? It's aiming to be cheaper than LFP I suppose. Tricky to get costs down before large scale but they must have an idea based on materials

[@travcollier]

Yep. That's the info I'm curious about too. Though just cost/kwh is probably not enough... IIRC, the economic case for flow batteries also depends on their longevity.

[@jollie1989]

@@travcollier agreed, it's not just cost per kWh storage, rather: total cost / capacity x cycles. I.e. cost per kWh stored or deployed. Roundtrip efficient Aso matters, but less so for long-term storage applications

[@nc3826]

flow battery is a complex mechanical system.... So simple "capacity x cycles" parameters do not play a role....

[@travcollier]

@@nc3826 Not much more complex than other sorts of batteries at these sorts of scales. Moving liquids isn't exactly exotic, and other large battery systems also require mechanical components for cooling (not uncommon for them to even be liquid cooled). There are folks who have thought a lot about relevant metrics, LCOS for example. But capacity*longevity/cost (or the reciprocal) is a decent rough metric to get a general idea.

[@nc3826]

complex - "consisting of many different parts or considerations" which is what a flow battery is relative to conventional battery cells.... it does not mean it's exotic or beyond comprehension.... Some forms of flow batteries have virtually no dendrite formation.... So other criteria become a first-order consideration....

[@theelectricwalrus]

This video has some great accents in it!

[@eMeeuwEngineering]

Did I miss it, or did you leave out the most important part? What does it cost?

[@Dominick13777]

Hoping it will be available for home use in the US.

[@jimsvideos7201]

To think, you could put these in the shade of solar panels, in the pylons of wind turbines and behind the drywall of interior walls.

[@mikebikekite1]

Curious why some of the batteries were being sent back for recycling. How long do the batteries last (recharge cycles or years)?

[@sunroad7228]

"In any system of energy, Control is what consumes energy the most. Time taken in stocking energy to build an energy system, adding to it the time taken in building the system will always be longer than the entire useful lifetime of the system. No energy store holds enough energy to extract an amount of energy equal to the total energy it stores. No system of energy can deliver sum useful energy in excess of the total energy put into constructing it. This universal truth applies to all systems. Energy, like time, flows from past to future".

[@wayne8113]

Thanks Rosie 👍

[@gconnery1078]

Love your videos but I have a broad question on alternative energies. If the atmosphere is a leaky bucket with heat coming in and going out, won't converting the kinetic energy of wind into electricity to keep us warm heat up the planet? Won't letting the geothermal energy out of the earth heat up our atmosphere. Will making electricity from nuclear to heat our homes do the same. I get that the CO2 blocks some of the holes in the bucket, but how does that compare to increasing the amount of heat production used to make more stuff and keep more people warm?

[@philliprobinson7724]

Hi. A good start, but pumps and motors running 24/7 mean more components to fail. The most successful systems will tend towards simplicity, longevity, and cheapness. Occam's razor cuts cleanly. Cheers, P.R.

[@rogerlette]

I would love a video about Kemiwatt startup. A flow batterie without bromine or vanadium.

[@thedirtjumper100]

Im confused about what actually diffuses through the membrane. Is it hydrogen ions as a result of le chelters principle, or it is bromine and zinc ions?

[@stopscammingman]

Sounds like these are really taking off

[@grahamkearnon6682]

I've been waiting yrs for a residential flow battery, the ability to go from 100% to zero if needed is significant as opposed to lithium chemistry at only 70% max usability. Also a stable power pak for home situations.

[@kevingooley6189]

I think you should have mentioned that if one wants more power one needs to add extra ion exchange membranes. How much power can be delivered per ion exchange membrane ？

[@TrueBluePlus]

Cool Video.

[@markzart33]

No mention of cost in the whole video, how much are they per kWh of storage?

[@epencrep]

Recharge cycles are the biggest drawback of traditional lipo batteries but LiFeP04 is way better at this with only minor loss in energy density per kilogram.

[@brianjonker510]

What are the global constraints to bomine production and is it more limited than zinc? This does seem a promising technology to economically compete at grid scaler.

[@incognitotorpedo42]

I can't really evaluate the economics of it until I hear cost per kWh, which was missing from this video. Zinc is pretty cheap. Bromine is more limited. It's gotten from various brines and concentrated salt sources, like dry or drying lakes. The ocean contains bromine at 65 ppm; that's 65 mg of elemental bromine per liter. Sea water is not the most economical way to get it, but you'd never run out.

[@peteinwisconsin2496]

As Redflow states on their website: > In our flow battery, dissolved zinc is 'plated out' as metallic zinc on one electrode surface, with bromide converted to complex bromine on the other ...< Re-plating the Zinc has been troublesome for other rechargeable zinc batteries because the rate of recharge makes for mossy (non-conductive) deposits, integral deposits or dendrites which short circuit the cell. Please share how Redflow solved the zinc replating problems that have previously limited the life of nickel-zinc and other batteries.

[@allanhugh2044]

Pete, the best I can assume from personal experience, I have two of these batteries; is their maintenance cycle. Every 24hr, 48hrs or 72 hours are the possible maintenance schedules the software lets you select. In a maintenance period the stacker plates are completely discharged so the battery has zero stored power. Then the system does a cleaning cycle, after that cleaning cycle you are starting with virtually a brand new battery. This strict maintenance scheduling is pretty much the secret of its longevity. The best scenario is for a complete 100% SOC to be obtained, followed by a 100% discharge to zero. This would (should?) reduce dendrite formation as far as I understand things. This 100% up then 100% down isn't real world stuff if you have it connected to your house; which we do. During the day the batteries are given whatever excess the rooftop solar can give them, 3½ years later and counting, we are quite happy with them. In effect, every day (we have 48hr maintenance intervals selected) we start with a brand new battery and one in use. This maintenance cycle requirement is also why it is necessary to have at least two of these batteries for continuous power storing and power releasing possibilities.

[@peteinwisconsin2496]

@@allanhugh2044 I agree with de-plating to 100% depth of discharge to clear the zinc deposits that are less than optimal, meaning dendrites or mossy deposits. I now recall that this same scheme was talked about for nickel-zinc batteries. As long as the zinc is the limiting factor(reagent), it should all dissolve at 100% discharge. You nailed it with the scheme of using two sets of plates. With modern electronics, a DC-DC converter can efficiently buck or boost as necessary to charge one battery while depleting the other, identical, battery right down to zero. That I know of, with the flow battery or Ni-Zn cells, one can cycle to 100% DOD every cycle with immunity. I speculate that with a charge schedule like this that no BMS is needed. There seem to be no issues with 100% DOD and only so much zinc in solution to cause problems at 100% SOC. Let's do this!