What is a Redox Flow Battery?

you know new, you jump on it. So thanks Andrew. To explain this method of energy storage, I will need to refer to a couple of things I have covered in previous episodes, so maybe not totally new, but this is okay. Let's talk about batteries in general. First. Now, I'm not gonna go into the history of voltaic piles and their evolution in the to the electrochemical battery of today, because I've actually done episodes on those topics already, But I do need to talk about what is actually going

on with a battery, how it generates electricity. The fundamental thing that is happening with a battery is that it is storing chemical energy and then converts that chemical energy into electrical energy. Now we all know energy cannot be created or destroyed, but you can convert it from one type into another. The classic example of potential energy, you know, you've got a rock at the top of a hill.

Transfer that into kinetic energy. You give the rock a little push and it begins to move and gravity pulls it downward, and you've got kinetic energy as the rock is moving. So that goes from potential to kinetic. Well, this case we're talking about chemical to electrical, but still same sort of concept, the conversion of energy from one format to another. Inside a battery are chemicals that undergo a reaction that causes a build up of electrons. Those

electrons gather at the anode. There are two electrodes on a battery, the anode and the cathode. The anode is the negatively charged end of the battery. It is the end that gives up electrons. So the chemical reaction is between essentially the electrode at the anode end and the electrolyte. But we also know that like charges repel one another, right, two negative charges are going to repel each other. It's like putting the north end of two different magnets close

together and they're gonna push against each other. Same sort of thing. So each electron is trying to get away from all the other electrons. It's trying to maintain the ideal amount of space between it and all of its fellow negative nancies. Now on the opposite end of the battery is the cathode. This is the positive electrode, the positive charge due to its own chemical reactions with the

electro light. Technically, it's drawing in positively charged ions. The ions are atoms that have a net charge, whether positive or negative. In this case, they are positively charged ions or cat ions. Opposite charges attract each other correct so negative attracts positive and vice versa. So that means the electrons are attracted to that positive side of the of the battery, to the cathode end of the battery. But unfortunately for these poor little electrons, between them and the

cathode where they want to go, there's more door. No wait, sorry, I read that wrong. Between them is the electro light, which in this case acts kind of like a really big bouncer who will explain quite convincingly that the electrons are not allowed to cross the line. In an electro chemical battery, we typically talk about semi permeable barriers or membranes, and these allow some types of particles to go through

but not others. You can think of it kind of like a filter, except this particular filter isn't based on particle size. Instead, it's based on particle charge. You got a positive charge, Hey, you can come on through, but only in one direction? Are you a negative nancy aka an electron? Sorry, can't get in boss's orders. So in this analogy, the cathode is like a popular nightclub and the electrons are folks who really want to get in there where the party is, but the bouncer just won't

let them in. But what if there were a side door that was unguarded, Well, then the electrons could take a different path to get inside the nightclub. And that's what happens. When a battery is placed into a circuit. The circuit is a path for electrons, and ultimately the circuit will connect the anode end of a battery to the cathode end of a battery, though it might not be the same battery depending on how the circuit arranges batteries.

We'll talk about putting batteries in series or in parallel in a little bit. So when a path is available, the electrons politely tipped their imaginary hats to the electrolyte bouncer and then they make their way through the circuit to get to that positively charged cathode nightclub, where the

electrons will rejoin chemicals and another reaction will occur. The technical term for this type of chemical reaction in which there is an exchange of electrons is a reduction oxidation reaction, and we can actually look at those chemical reactions at the two electrodes that we talked about earlier as the two halves of this reduction oxidation reaction. Reduction refers to

gaining electrons. That sounds counterintuit if I understand, because typically you don't refer to something gaining anything as a reduction, but in this case is because we're talking about the electric charges here, not sub atomic particles. We're talking about the reduction of electric charge going more negative, which would happen when you take on an electron. So the component is accepting electrons and it undergoes a reduction and electric charge.

Technically it goes from more positive to typically neutral oxidation refers to giving up electrons. When an element oxidizes, it is losing electrons. So when iron oxidizes, it rusts, and if you break off tiny pieces of iron, they oxidize so quickly in the atmosphere, and that chemical reaction gives off so much heat it does an exothermic reaction, you end up with sparks. There is a faster way to

say reduction oxidation reactions, and that would be redos. So that gives you a hint that we're going to be coming back to this when we move on to redox flow batteries. But we've got a little bit more finishing up to do with classical batteries first. Now, typically the circuit the electrons must travel through isn't just an open path. We expect those electrons to do some work along the way, and the electrons don't really care about that. They just

want to get to that sweet cathode nightclubs. So we tell each electron, hey, buddy, i'm gonna let you in, but first i'm gonna need your help to light this light bulb or pow are this radio or I don't know, give my captain Kirk realistic figuring with real gorn punching action the ability to hit that jab, and the electrons do this always with the goal of getting through it to the cathode nightclub. Doing work is hard, but getting

past the electro light bouncer is physically impossible. I mean in the real sense of the word physics, though I guess I really should use chemistry. At least, the electrons will do the work if they have the energy necessary to do that work. So let's say that in our analogy, the work that the electrons have to do is to lift a very heavy weight, and the electrons all have the same amount of energy or weightlifting ability, but collectively their ability is not enough to move that heavy weight.

They can't budget well. In that case, the battery will fail to power the circuit. The electrons will not make that journey after all, It's almost as if they ran into a second bouncer. So the energy that the electrons have is dependent upon the standard potential between the cathode and the anode. That is, how great is the difference between the negative charge on one side and the positive charge on the other side. The greater the difference, the

greater the potential between the two. This gives us the batteries overall electrochemical potential, and that in turn determines the voltage of the battery. Voltage is akin to pressure, how much force is there in the system pushing those electrons along. The force determines whether or not electrons flow. If there's not enough voltage, the electrons won't move. If there's a

lot of voltage, they're gonna move too sweet. So if the weight is too heavy, if the load on the circuit is too great, then it's going to require greater force or voltage to do that work with the same amount of electrons. Alternatively, you might be able to do that work if you had more electrons a larger volume of electrons moving through at that lower voltage. This would be a description of current or amperage. But one or

the other needs to go up. If the electrons are going to be able to move that weight to to power that load on the circuit, there needs to either be more of the electrons, or they need to be pushed harder, or you know both. It all depends on what the circuit can handle and things like that. So you can have a high voltage and a low amperage, which means you've got a lot of pressure behind a

relatively small volume of electrons. Or you could have low voltage and high amperage, in which a relatively small amount of force is moving a relatively large volume of electrons. Or you could have any combination. So your typical household batteries have a voltage of one point five and these would be your classic double A or triple A batteries for example. They're all at one point five volts. Okay, But let's say you've got a job and it's going to be too much for the battery to handle based

on that batteries voltage, what are your options. Well, you could use a different type of battery if your system allowed for that battery that had greater electrochemical potential between the two electrodes. But the other option is to stack the batteries together in series. This has an additive effect on the batteries voltage. Now if you were to connect the batteries in parallel instead of in series, So in series, you can think of them as one right behind the other.

In parallel, they're all kind of linked up in their own individual pathways into the main circuit. Well, if you go in PA Hello, you increase the amperage, you increase the current, but not the voltage, so it all depends on what you need to do. Now, some batteries can only do this process one time through all the way through it. So once the cathode nightclub gets full of enough electrons, it will lose its positive charge. The electrochemical

potential between the anode and the cathode will decrease. The population of electrons at the anode, entrance of the nightclub will diminish, and so even if you have a pathway that gives electrons a free and clear entry point to the cathode with no load to to work, it won't matter because there won't be enough electric potential difference for there to be any voltage to be any flow of current.

So essentially the cathode nightclub has reached kind of a neutral charge and no electrons are gonna want to go there now because it's some lame spot no one cares about. The battery is dead and it needs to be discarded or preferably recycled. But other batteries are rechargeable, and putting them into a charger means that you're actually introducing an incoming electric current into the battery, and it forces this

reaction to reverse itself. The electrons will bail on the Cathode nightclub and return to the anode end, and when you remove the battery from the charger, it's back to where it was before you used it the first time. Mostly, typically, rechargeable batteries recapture only a percentage of the full charge they once held, which in our analogy would mean some of those electrons were just too much in the groove and the Cathode nightclub, so they didn't leave when everyone

else got kicked out. So over time, even a rechargeable battery will lose its ability to store energy. The electrochemical potential will become too low for the battery to do any useful work. I mean, you might be able to hook it up to a meter and say, yes, technically current is flowing, but it's at such a small amperage that it's not useful for anything. I can't do it to light a light bulb or whatever. So that's your classic battery. There's another energy storage method we should cover

as well, as it's going to be useful. When we talk about redox flow batteries and that would be fuel cells. Fuel cells are similar to, but distinct from batteries. Sir William Robert Grove, a Welsh judge, generally gets credit for inventing the first fuel cell all the way back in eighteen thirty nine. I guess this tells us that Welsh judges had a lot of spare time on their hands

in the mid nineteenth century. Basically, Sir Willie found out that by mixing hydrogen and oxygen in the presence of an electro light would end up with some interesting byproducts. He would get water, you know, good old H two O two hydrogens to one oxygen and electricity. But this particular incarnation of a fuel cell, well interesting, wasn't practical because it wasn't producing enough like tricity to do anything of use. However, we're gonna skip way ahead. Fuel Cells,

like batteries, convert chemical energy into electric energy. There are many different kinds, but the ones you and I would most likely encounter are those that use hydrogen and oxygen, much like Sir Williams fuel cell from more than a century ago. In a fuel cell, you've essentially got a couple of chambers separated by a semi permeable membrane. In one chamber you pump in hydrogen and in the other

chamber you pump in oxygen. The semi permeable membrane is an electrolyte, typically paired with a catalyst, and a catalyst is something that facilitates a reaction. It doesn't cause a reaction on itself, but it makes reactions easier. It reduces the the energy requirement for a reaction to happen. So the hydrogen atoms, which consist of one electron and one proton that's a hydrogen atom, they react with this electrolyte and the catalyst. This causes the hydrogen atoms to say

bone voyage to that electron. So you get a positively charged hydrogen ion or the cat ion, and that would be the positive hydrogen uh anions are then negatively charged ions, thus like cathode and anode, and we have another word for hydrogen ions that would be a proton, because that's all a hydrogen nucleus really is. It's one proton, so positively charged sub atomic particle. The semipermeable membrane allows the

proton to pass through it, but not the electron. So like our previous example, the electrons really want to get to that other side of the membrane because that's where a positive charge exists. So you can connect the fuel cell to a circuit and the electrons will travel through that path and head toward the opposite chamber and they'll do work. They'll do work on an electric load along the way. How much depends again upon the electrochemical potential

between the two electrodes, the anode and the cathode. And then they'll get over to where all the oxygen and hydrogen uh nuclei, the protons, those cat ions all happen to be. Now, I have a little bit more to say about fuel cells, but before I get into that, let's take a quick break. So before we left off, I mentioned that the hydrogen in a fuel cell gets stripped of its electron. The hydrogen cation or proton, passes

through this semi permeable membrane. The electron goes through a circuit, doing work along the way before finally making its way to the other chamber in the fuel cell. In that opposite chamber, the protons, electrons, and oxygen combined to form water. This is also an exothermic reaction, meaning it gives off heat, So your byproducts of this reaction are electricity, heat, and water.

The fuel cell only generates electricity so long as there is hydrogen and oxygen a k a. The fuel that's in the cell, and that means that once it runs out of those, you have to refuel it. This is not something that just stays contained within the fuel cell. You're refueling it, just as you would have to refuel something like a car, you know, to top it off. And it is a clean process within the fuel cell

itself because the byproduct is pure water. People have advocated for fuel cells to replace stuff like gasoline or diesel powered vehicles. So what's stopping us? What is in the way of doing that? Well, there are a few challenges, and one is that hydrogen is actually not that easy to come by. Now what do I mean by that? I mean, we know hydrogen is the most plentiful stuff in the universe, so you figure it would be the easiest stuff in the world to get hold of. But

hydrogen also tends to bond with other stuff. In its pure form, hydrogen is a gas and it's lighter than air, so it floats off beyond our reach. We typically get hydrogen through some other process which involves breaking the molecular bonds that hold hydrogen to other elements. But that means you have to actually pour energy into this process. In order to get to the hydrogen, you have to break

those molecular bonds. That requires using energy. So to swap out to a hydrogen based system, you have to take that part into account. Now, if it turns out you're using more energy to get the hydrogen, then you would get energy by harnessing that hydrogen. You're playing a losing game, right. If you're spending more energy just to get the fuel, then you are being able to use the fuel. Why are you doing that? You should just choose some other method.

Or if the method you're using to break those molecular bonds doesn't depend upon an environmentally friendly method, then really you're just shifting pollution to a different part of the system. Now, you can get hydrogen out of water by running an electric current through the water. In fact, this is essentially the same process we see in fuel cells, but in reverse, right, because in fuel cells we see hydrogen and oxygen binding together and the byproduct in this is electricity and some heat.

By running an electric current through water, we can break up oxygen and hydrogen, and you know, we break that molecular bond, so again the same process, but in reverse. It's actually called electrolysis. But in order to do that,

you have to have access to suitable water. You need a clean method to generate electricity, maybe use solar power or wind power, And all of this starts raising questions about why would you not just use solar or wind power directly, So you couldn't really do that for like an onboard system on a car, and the counter argument is that you still have to have a way to store energy. Fuel cells would be a way to help store energy, but there are other challenges besides the access

to hydrogen. Another big one is that most fuel cells have a band of temperatures within which they can operate, and if you get outside that band of temperatures, if you go too high or too low, the fuel cell will not perform as well and it might even suffer damage, which means it will have a much shorter life cycle. Anyway, most fuel cells don't operate very well below a certain

threshold temperature. The specific temperature threshold really depends upon the type of fuel cell, and this makes them a little less reliable if you want to, I don't know, have a fuel cell powered car in Alaska in the middle of winter, the temperatures can actually get low enough where it's below the real operating temperatures for that fuel cell, and it might even do damage to the fuel cells membrane.

So this is a tricky problem to get around. And yet another challenge is that many fuel cells rely on rare and expensive materials to act as catalysts, such as platinum. And yet another challenge is that many fuel cells rely on rare and expensive materials to act as catalysts such as platinum. Platinum is expensive stuff, and that drives up the cost of manufacturing. As much as I wish we

could all ignore the impact of money, we can't. If you have two ways to store energy, and one is relatively cheap but environmentally it's harmful, the other is expensive but has no real negative environmental impact, some people, perhaps most people, are going to go with the less expensive option, even though in the long run you could argue that it's more expensive and to have a true hydrogen based economy, you would also have to invest in building out a

new infrastructure, which can run into the billions of dollars, so it's another big challenge. Also, I should point out that while the actual chemical reaction within a hydrogen based fuel cell is a clean one, there can be other factors that cause a negative environmental impact, including the mining methods that you have to rely on to get the materials for the catalyst. You always have to take a big picture look at these things and not just look

at the mechanism of the fuel cell itself. You gotta look at the whole ecosystem and say, does this make more sense than fossil fuels. I would argue it does, but you have to take the whole picture into account before you can actually say something like that. And I'm not saying all of this to completely dismiss fuel cells, because I happen to love fuel cell technology, but I also believe we have to acknowledge the obstacles that are in our way if we ever are to have a

hope of surmounting those obstacles. Now, let's finally move on to redox flow batteries. Now, luckily, with the grounding we have of in traditional batteries and with fuel cells, we can tackle this concept a bit more easily. Lawrence H. Thaller filed a patent for an electrically rechargeable redox flow cell back in nineteen. The Patent Office in the United States granted that patent the following year. The abstract gives us a really useful starting points, so I'm gonna read

it in full. Also, this patent expired in so this is about as fair use as it gets. But here's the abstract. There is disclosed a bulk energy storage system including an electrically rechargeable reduction oxidation redox cell, divided into

two compartments by a membrane. Each compartment containing an electrode and anode fluid is directed through the first compartment at the same time that a cathode fluid is directed through the second compartment, thereby causing the electrode in the first compartment to have a negative potential while the electrode in

the second compart mint has a positive potential. The electrodes are inert with respect to the anode and cathode fluids used, and the membrane is substantially impermeable to all except select ions of both the anode and cathode fluid. Whether the cell is fully charged or in a state of discharge.

Means are provided for circulating the anode and cathode fluids, and the electrodes are connected to an intermittent or non continuous electrical source, which, when operating, supplies current to a load as well as to the cell to recharge it. And sillery circuitry is provided for disconnecting the intermittent source from the cell at prescribed times and for circulating the anode and cathode fluids according to desired parameters and conditions.

And that's the abstract. Now. I'm sure a lot of you out there are way up to speed with what's going on. But for those of us like me who find the language of patents to be a teen c bit difficult to parse, let's break it down, and we're gonna start with the core, the cell of this flow battery where the electricity gets generated. This core has two compartments, each with its own electrode. One electrode the anode, is the negative terminal, the other, the cathode, is the positive terminal.

And this is just like a battery or a fuel cell. A liquid electrolyte pumps into each side of the core. In between the two compartments is a membrane separates the two cores. In between the two compartments is a membrane that separates those two compartments, right, it's right there in the middle, and it allows certain ions, certain charged particles to pass through, but not electrons. These compartments connect to respective electrolyte tanks, so big reservoirs, and the tanks hold

the positive or negatively charged ions. Pumps on either side take the respective electrolyte from the respect tank and pump it into the respective compartment in the cell, and then within the cell, the ion exchange can happen across the membrane the anode side or the analyte because that's anode plus electrolyte releases electrons in this process, which then can go on and do work in a circuit before joined

the cathode plus electrolyte on the other side. The respective liquid electrolytes now continue to move out of the cell and back into their various tanks. However, this means that the electrolytes are now chemically different because of that ion and electron exchange. They're no longer the same ions that they were when they were being pumped into the cell and having that exchange right now they're inert, at least with respect to each other. They no longer will have

that reaction. You won't have that electrochemical potential where that exchange could happen again. So let's say you've pumped through the entire air supply of electrolyte through both tanks. You know, it's been pumped all the way through and refilled, and

now we've got these inert electrolytes. You would eventually find you are no longer producing any electricity because enough of the electro light has gone through this exchange that the electric potential between the cathode and anode is no longer sufficient for that to continue. So it's kind of like having a dead battery. However, this process can be reversed, just as with a rechargeable battery. So if you pour the electricity into the system, you cause the reverse of

this chemical reaction. You recharge the electrolytes that are on either side, that are in either compartment, so that once again you have negatively charged electro light on the anode side and positively charged electro light on the cathode side, And you would pump these electro lights through the cell, they would get recharged then they would go back into their tanks, so you're gradually reach our ing all the electro light that are in either tank until your back

up to full capacity. This reminds us that batteries are not a source of energy. They are a form of energy storage. We have to put energy into them in order to get energy out, so we're not like mining electricity here. And now we're getting into how these batteries might be used. So let's say you've got a farm of solar panels and they're generating electricity. It's a bright

sunny day and they're generating electricity like gangbusters. That electricity needs to either be put to work immediately or it has to be stored otherwise it goes to waste. And this is true of any method of generating electricity, by the way, not just with solar panels, but with traditional power plants. Our power plants try to match production to meet demand, but sometimes demand is low, such as say in the middle of the night when most folks sleep,

and the power plants then have options. They can try in store excess energy in some other form and some other solution so that it doesn't just go to waste. One way of doing This is through hydro pumping, and I want to describe this because there's some analogies between hydro pumping and redox flow batteries. Hydro Pumping is a fairly simple idea. Let's imagine that you've got two reservoirs of water, but one is at a higher elevation than the other, so it's up a hill. From the higher reservoir,

you have a tunnel. This is called the intake tunnel. That tunnel leads down into a powerhouse under the ground, and that powerhouse contains a turbine that water can turn. So water flowing down due to gravity hits this turbine and the force of it causes the turbine to rotate. This powers and electrical generator, generating electricity. As the name implies. The water then continues to flow out a second tunnel, the discharge tunnel, and this tunnel empty is out into

the lower reservoir. So effectively, water is just flowing downhill, right. It's coming from an upper reservoir down through a tunnel. Happens to have to do some work along the way, and then continues down until it hits the lower reservoir. It just needs gravity to work. But to recharge the system, the powerhouse turbine has to actually be activated. We have to pour energy into it and turn the turbine in

the opposite direction. Now it's acting like a pump, and it forces water from the lower reservoir and pumps it up against gravity into the upper reservoir. So when a power plant is generating more electricity than the current demand requires, it could send that excess electricity over to the hydro pump station. The hydro pump station activates and begins to pump water from the lower reservoir into the upper reservoir,

and then they have that energy stored. But if the power plant ends up seeing a demand for electric see that exceeds its own ability to produce electricity, the hydro pump can jump into action and it can open up those tunnels and allow gravity to have water turn a generator, and thus you get to augment the power plants capability

of producing electricity. So again it's just storing energy. Well, the same sort of thing is happening with the redox flow batteries and for much the same purpose, except instead of using gravity and kinetic energy to provide what we need,

we're talking about an electrochemical process. We're still using pumps to circulate liquid electrolyte from reservoirs through an electric cell, but we discharge the redox flow battery by having this ion exchange, and the active elements in these reservoirs begins to reduce and we recharge by reversing the process, we pump electricity back into the battery to recharge the respective electrolytes so that the tanks are full of active components.

The capacity of a redox flow battery depends upon the size of those tanks. The electrochemical potential of a redox flow battery will always depend upon the specific electric lights being used. It doesn't matter if you have more or less of them, So you choose your electrolytes that's going to determine that electrochemical potential. So in other words, that determines what the voltage of your battery is going to be.

And it doesn't matter if you have small tanks full of the stuff or big tanks full of the stuff. The difference is that the size of the tank determines the capacity, the amount of energy overall that it can store, and that depends not just on the size of the tank, but also on which electro lights you choose. Some electro light pairings are more energy dense than others. Some are more energy dense but much more toxic, or they're more

expensive or both. So there are a lot of different considerations you have to make when you're choosing your electrolytes. But the size of the banks you're really just limited by. You know, your facility, and if you have the facility to make a truly enormous pair of tanks, then you've got a battery that's got an enormous capacity to store energy. They're not going to release that energy all at once,

but it's going to store a lot of it. And like traditional batteries, you can actually connect redox flow batteries in series, so you can create a higher voltage that way too. Instead of having to swap out what electrolytes you plan on using, you could just make a series of these redox flow batteries and get a higher voltage

by connecting them that way. Now, when we come back, I'll talk a bit more about some of the types of electrolytes used in these redox flow batteries, since again it determines the voltage as well as the use cases for the batteries and some recent advancements in that technology.

But first let's take a quick break. So from the moment they were first invented in the late sick season and patented in the seventies to present day, the choice of which materials to use as the anode and cathode electrolytes have guided the evolution of the redox flow battery. Early redox flow batteries included a zinc chlorine pairing chlorine is incredibly dangerous stuff, zinc bromine, Later zinc serrium batteries

were used. Vanadium based redox flow batteries have been used, and lots of others, and they have a range of capabilities when it comes to stuff like electrochemical potential, energy density, power density, toxicity, cost, and recycling. Recycling by the way, I don't mean to recycle the materials, but rather how many recharge cycles does this battery have? How many times can you charge it back up to full and discharge it in full and not lose any energy storage capacity.

Rarer elements are obviously more expensive, that's kind of a given, and some of these are actually more like hybrid style redox flow batteries which require some extra components, or they include specially treated electrodes where one of the two electrodes has UH elements on it that make it either the anode or the cathode. The zinc ones also have to contend with a tendency for zinc to coat the electrodes. You get almost like an electro plating, but it's of zinc.

And if that happens enough, then the electrodes has become less effective. They're no longer able to transmit electrons, so you eventually have to strip those plates of that zinc coding. More recently, researchers with the University of Southern California announced that they were working on a redox flow battery that uses an iron sulfate solution, and that is super cheap to get hold of because it's a byproduct from the

mining industry. It's essentially waste. So the other component in this particular approach is an acid called an stick with me guys an through quine known disulfonic acid and I'm sure I mess that up, but it's a q DS is how everyone refers to it, because no one wants

to say that name. Now, one major advantage of this entire approach that the University of Southern California researchers have suggested is cost because the components are plentiful and they are inexpensive, so it brings down the cost per kill a lot hour of providing electricity using this method, and

that's a big deal. Now. In addition, these batteries again have different cycle capacities, so that whole discharge recharge cycle redox flow batteries typically have hundreds or thousands of cycles, sometimes between ten and twenty thousand cycles, which means that you can use the same supply of liquid electrolytes over and over. In fact, some people say that they effectively

have an indefinite number of recharge icals. It's really the other components that you have to frequently swap out, like you will eventually have to replace the pumps or you may have to replace the electrodes or the membrane, but that the electro light fluids for a very long time will just be stable. The redux flow battery is good for the load balancing applications that I mentioned earlier with power grids, and compared to some other battery technologies like

lead acid or lithium ion batteries. Redux flow batteries tend to have lower power and energy densities. They can't hold as much, but they work well with large applications like power grids, and they scale right, so there's a balance there. However, the requirements of the redux flow battery are such that they are not good for smaller applications, which you could easily imagine. Right, you're not going to have these for your cell phone. They're not good for portable or tiny applications.

The requirement of the reservoir tanks means this tech does not scale down well. You would want this for large stationary applications, so you could pair it with stuff like green or energy technologies like I had mentioned before the break, like the solar panel farm, because with wind power or solar power, redox flow batteries can help balance out the natural drawbacks of those methods. We know the sun doesn't shine all the time because that slacker takes practically every

single night off, nor does the wind always blow. So using energy storage to help balance the load during times where you cannot easily produce electricity directly is critical. You need some way to store the energy when you're producing a lot of it and some way to release the energy when you're not able to produce it. And that's really one of the key elements for going with a renewable green energy source. Bringing the cost down on that

energy storage makes renewable energy solutions much more viable. It's a it's a key component of doing that. And as I mentioned earl here, if you have a renewable method to generate electricity and you have one that relies on, say, fossil fuels, and you've got a pretty high price tag for your renewable energy, it's hard to get a lot of people to switch, or maybe hard to get large power companies to switch. After all, the economically viable option is to go with the lower cost so you get

higher return. You don't want to spend more money and make less money, at least not from the perspective of business. If we take that from a perspective of environmental impact, there's a different argument to be made. But we have to remember we live in the real world where all of these factors are playing a part making the whole enterprise economically advantageous. By enterprise, I mean renewable energy. That's a huge move and we're starting to see it already.

I mean, we've already seen the price of energy production through renewable technologies to come down significantly to the point where it's actually very competitive with fossil fuels, in some cases more advantageous. And having this component, the energy storage component, be part of that is critical. But that's pretty much

all I have to say about REDOS flow batteries. To get into more detail would really just involve talking about the specific ion exchanges with each pairing of electrolyte materials, which would become a chemistry lesson, or talking about how much energy those individual electro LTEs hold per unit of volume and how expensive they are, which would becomes sort of a cost benefit analysis of the different types of electrolytes. And really I'm not keen to do either of those things.

But the important things we've covered the basic technology of it. So you're not likely to encounter a flow battery for home use, but some large buildings might take advantage of one as part of a load balancing UH strategy or backup generator strategy. More likely, power plants and renewable energy facilities will use them, as I've said, but you never know.

But I do think it's a pretty interesting technology, one that relates very closely to those others that I mentioned before, but is different enough where I thought it was cool to really tackle it. If you guys have any suggestions for me to cover in future episodes of tech Stuff, whether it's a specific technology, maybe it's a company or a person in tech, Maybe it's just a trend in tech that you want to know more about, let me know. You can reach out to me on Twitter or Facebook.

The handle for both of those is text stuff H s W and I'll talk to you again really soon. Text Stuff is an I Heart Radio production. For more podcasts from I Heart Radio, visit the I Heart Radio app, Apple Podcasts, or wherever you listen to your favorite shows.