TechStuff Classic: How Hydrogen Fuel Works: Part One

each episode a different title. But yes, as the title reveals, this is the first half of a two parter about hydrogen fuel. Fascinating stuff. And you know, there were a lot of people who were predicting a hydrogen fuel based economy probably about two decades ago, and we're still not there yet. So we're gonna learn more about this fuel source and what it is and how it works and why we don't actually have hydrogen fuel fueling everything these days.

So let's take a listen. We're going to describe everything about hydrogen and how it's being used in multiple ways. Yeah, because hydrogen is a really simple element with a huge amount of potential. Simplest element in the universe one proton, one electron. That is it, get yourself a proton, get yourself electron and let them make friends. You've got a hydrogen. So it's also the most abundant element in the universe. It's it's everywhere. This is the stuff that the Sun

fuses into helium at a temperature of millions of degrees. Yeah, we have had to put that in there. Uh yeah, so so it's technically fueling well everything, I suppose once you've got it working in the sun. Yeah. Yeah, pretty much everything on Earth, life as we know it exists because of hydrogen being built into helium in the sun.

There are some exceptions, like you could look at some extreme of files in Earth where they're living off chemicals that are being produced by the gases and things being released in deep undersea fissures. But most of life, the vast majority of it, depends at least in some part on light. Yes, and hydrogen. Although we have only known about its existence as an element for a relatively short

period of time, has has been kind of theorized about. Yeah, there's been people who have worked with what they called like they had various words for it, inflammable air, being a popular one because they realized, hey, there's the stuff that when you do things to other things happens. And then if you put a fire near it, it blows up, right, inflammable meaning inflammable meaning inflammable, Yes, exactly able to be set fire to. Right, And in this case, it's not

just that it burns, it's exclusive. So the word hydrogen's actually combination of two words from Greek hydro and genus, which together mean water forming. And once you know about hydrogen and you know what water is, it's H two O. Makes perfect sense. You've gotta have hydrogen or you don't have water. Of course, if you don't have oxygen, you still don't have water. And while this hydrogen stuff is everywhere, I mean, it's the most abundant element in the universe,

it isn't often found on it's lonesome. That's because it makes friends really easily. Yeah, it's it's kind of like the opposite of me. It actually gets real buddy buddy really fast, and and and the buddies like it. See I got half that equation. But anyway, hydrogen forms compounds readily, right, you get compounds and all sorts of stuff. You get water being a big example at hydrogen bonds with oxygen. You have water, you have lots of hydrocarbons, you've got um.

You even have occlusion, which is molecular condensation inside igneous rocks. The point is is that it's bound up with other stuff. It's not just out there its own. So if we want to harvest hydrogen to use as fuel, you gotta think a little outside the box. You can't just go to the hydrogen store by it. Yeah, it doesn't grow on any hydrogen trees. Now you have to you have to do something to something else generally in order to get some of it exactly, which means you've got to

expend energy in order to get this fuel. And that's one of the things that's really important about any sort of fuel. It's not just hydrogen. We're talking about any kind of fuel where you're planning on getting energy out. If it requires you to put more energy into it to get the fuel, then you're getting as a benefit of the fuel. Is a losing proposition, right. Although there are lots of different ways to to produce hydrogen um.

You can use light to split water molecules, you can gasify biomass waste, you can even just kind of let a bunch of microbes do the work for you as part of their normal metabolism. Um. But one of the most popular ones right now anyway, what accounts for about of the hydrogen in the United States is something called performing, in which a carbon based fuels like natural gas typically methane,

are reacted with steam at high pressures and temperatures. That produces hydrogen, a little bit of carbon dioxide and carbon monoxide, that last of which is then reacted to produce more hydrogen and carbon dioxide. UM. You will note that that both of these do produce greenhouse gases, so it's a little bit less friendly than something like electrolysis, although you have to pump a whole lot of energy into electrolysis.

We'll talk a little bit more about that later. Overall, reforming does have the potential to overall reduce our carbon footprint if it could provide the hydrogen for like a whole fleet of fuel cell vehicles. Right That's one of the big things about hydrogen. We'll talk about that in just a second, about how it does not give off greenhouse gases in ideal cases. Uh, keep in mind we're talking ideal cases because it all depends on how you're

using the hydrogen. So, uh yeah. I also read that there have been some studies of algae that give off hydrogen, which, you know, if we were ever able to make an algae farm that was efficient enough, that would be a great way. But there are a lot of people who question whether or that that's practical. It may not ever be something that generates enough hydrogen for it to be worth the amount of effort it would take. Again that sort of energy losing proposition night. So some other things

about hydrogen. It has a low ignition energy. That means you don't have to apply a lot of energy to it to get it to ignite. That makes sense, you know, it doesn't take much to set it on fire, essentially, is what we're talking about here. It actually requires an order of magnitude less energy to ignite hydrogen than it does to ignite gasoline. Yeah, so that means that gasoline is pretty pretty flammable, pretty or inflammable. Yeah. Kids, let's not play with the stuff at home, shall we, or

anywhere else for that matter. Let's treat it like serious business. But it's both a good and bad thing, right because the hydrogen stance it's easy to ignite, means that you can easily implement that in an engine. Uh does it very efficiently. You don't have to spend a lot of energy to make it do what you wanted to do.

On the other hand, because it has such a low ignition point, it's also a challenge engineering wise, because if your engine gets hot enough, the engine itself could cause the hydrogen to ignite prematurely before it gets into the operative fits right, and then it could make everything inoperative. You would get an operative right quick. So that's you know that there's a there's a good and bad side of this. If you can engineer your way around it,

it can eventually be a benefit. Oh sure, it technically has the highest energy output by weight of any fuel um though it is the lightest elements, so that's kind of yeah. You kind of have to get a lot of it together too. So it's because it's it's not dense,

you know, which is something else will chat about. So one of the reasons why we're even talking about hydrogen, one of the big ones, it's what we alluded to earlier, is the fact that the combustion is really clean, particularly if you're using hydrogen and pure oxygen as the mixture that goes into your engine, right, because then your output

is going to be just energy and water. Yep. You get energy in the form of the power that you generate and some heat because of course we don't have any perfect systems where we don't lose some energy in the form of heat. But yeah, the only other thing you get is water. You don't get anything else. And this is when I when I talk about mixtures. We'll talk about combustion engines a little later too. This is a typical thing where you mix together some fuel and

some air to go into a combustion engine. Same sort of thing with hydrogen. You're not putting just pure hydrogen and you're mixing it with some form of air, in this case oxygen. However, that being said, most hydrogen combustion engines are not using pure oxygen to mix together to make the combustible mixture. They're using air. So air has stuff in it besides oxygen. In fact, the primary component

of our atmosphere is not oxygen, it's nitrogen. So one of the byproducts you get with using a hydrogen combustion engine that uses air is that you get some nitrous oxides, nitrogen oxides, I should say, not nitrous oxides, which would be hilarious until you suffocated, but nitrogen oxides. Uh, that's a that's a pollutant. You don't want that. Um. And you can also get carbon monoxide and carbon dioxide if you get some oil seeping into the combustion chambers, because uh,

oxygen does. Our atmosphere doesn't have like tons of carbon in it, but oil does. So there are chances of having a hydrogen combustion engine this kind of pollutants. You can get around that if you wanted to go with fuel cells, and we'll talk about those two. We'll be back with more discussion about hydrogen fuel in just a second, but first let's take a quick break. So the amount of power that hydrogen engine can generate is dependent upon

a few different things. It depends upon the mix of air and fuel and how that fuel is injected into those combustion chambers in your engine. So, theoretically, the maximum output of a hydrogen based combustion engine using a pre mixed method. This is where you have like a carburetor type situation that is mixing air and fuel together and

then it goes into the combustion chamber. Uh. If you're using that method, theoretically your maximum output is about eight of the power generated in a comparable gasoline engine, So not as powerful, right, But if you were to take a direct injection approach, which mixes the fuel and air after the intake valve in the combustion chamber closes, then the hydrogen based engine can theoretically produce fift more power than a gasoline engine. So you kind of have a

less in one way or pent more the other way. Um, However, this is all based upon the idea that you're using exactly the amount of air you need to complete combustion, so you're using just the right mixture of air and just the right mixture of hydrogen. But the downside of that is that you also produce more pollutants that way. Right. Although okay, so, so this is a complicated issue and the numbers on it are always going to be rough.

But when you're talking about fuel efficiency, you you need to use more gasoline in order to make an engine do the same amount of work than you would hydrogen. Yeah, exactly, Like you have this note about gasoline vehicles operating at around efficiency. What that means is that of all the energy that's being generated is actually going to doing the thing you needed to do. The other is being lost in some way or another. Sure, you usually due to

heat loss. That's the big one, especially with engines. I mean, engines generate lots and lots of heat. The the ideal of a fuel cell vehicle using hydrogen, it's closer to six efficiency. For for the record, electric cars may manage somewhere between twenty five and sixty fuel efficiency depending on where you get the electricity to recharge that battery. Right, and and if you want to be really technical, a fuel cell vehicle is kind of a subset of electric vehicles.

It's just that it's an electric vehicle that you are refueling with hydrogen rather than a closed battery system exactly. So, yeah, it's a great point. And that's another thing that we have to take into consideration. Now. Typically, if if we're talking about you know, I just mentioned about having just enough air and fuel to complete combustion, and you get that that crazy hundred and fifteen percent of a gasoline power engine, but you produce more more pollutants as well.

Usually we're not using exactly the amount of air because we want to cut back on those pollutants. One of the big reasons we want to use hydrogen is to cut back on pollutants. So if we're producing more pollutants by making it really efficient, then we're like, well, we just kind of traded off. That was a lot of money to not do any better exactly. So what we tend to see our engines that use about twice as

much air as is actually required to complete combustion. Now, this reduces pollution, but it also reduces the output of the engine. Yeah, sad trombone. Okay, so these are just tradeoffs. This is the way the real world works. We have to sit there and say, Okay, there's not a magic solution that is going to solve all the problems equally, we have to start making tradeoffs. This is a pretty good one because you can you can enlarge the engine

size and make up for a lot of it. Right, So if you make the hydrogen based engine larger than a gasoline based engine, you can kind of make up this this loss. Now that does, of course, mean you have to redesign vehicles around a larger engine. So I mean it's you know, it's those domino effects, right. You could also include what's called a turbo charger or supercharger, and you might wonder, hey, how did those work. We'll do another episode because it's already going to be a

long one for this one. So we can't. We can't sit there and uh and jump into that and hope to make it out alive, because no will kill us. The protective barrier is only so strong. Okay. So, like we said, hydrogen not very dense. When you've got one proton and one electron, you don't expect it to be Nope,

So it's uh room temperature is a gas. Getting enough hydrogen together in one place to be useful as a fuel takes a lot of work, and some of the easiest ways of storing it, like in extremely cold liquid form, aren't really practical for toting around in a consumer motor vehicle that might not want to incorporate a complex cooling system due to you know, cost and weight and space issues. So usually we end up having to figure out a way of pressure rizing it under intense amounts of pressure. Now,

that of course creates another safety issue. Anytime you have a compressed gas, it's under a lot of pressure. If

you rupture that containment unit in some way. Yeah. You that's and then at on top of that that the gas itself is inflammable, and you've got the potential for really, really a bad day, Which is why a lot of companies that have looked into using hydrogen as a fuel in one way or another, whether as a bustin engine fuel or whether as a fuel sell fuel, have put in a lot of research and development in safety for

these hydrogen canisters or you know else. They will never be able to market it because it would just be too dangerous. Although some people argue that, I mean, gasoline tanks being driven around are also that's a it's a good point. It's a fair point. I mean, we're we've been relying on a technology that has a an inflammable fuel for more than a century. And you know, although it's not quite as dangerous as movies make it out

to be. I mean, it's not that. Yeah where where you you your car your car sways a bed and then explodes. Y. Yeah, so if Michael Bay made cars, no one would ever get in them. But fortunately, as far as I know, he has not made one. Uh so, uh yeah, We've we've been making use of this hydrogen for a long time, and in fact, we, like Lauren said, we were kind of playing with this stuff before we even had any idea of what it was. We didn't

really know about elements or even gas is. So we're gonna take you on a historical journey, and along this journey will be explaining how some of this stuff works, because we figured we'd kind of incorporate both the history and the technical stuff altogether. It's an experiment. Now before we jump into the way back machine, because I know all you guys have been missing it, Laurence looking at me terrified. Yeah, Lauren, that's what that big thing is

in the corner that we haven't been using. It's all dusty and stuff. Turns out it wasn't in Mongolia. It was just in a supply closet. Alright. Well, our our fuel gauge is not on empty yet. We still got a bit more to go, but first let's take another quick break. Okay, So we're back and we're ready to get into the way Back Machine, which I know is going to sound absolutely amazing. I can't believe all the bells and whistles that indicate to you that we've actually

traveled back in time. Because in truth, it's silent. But we have to give you some you know, way of knowing that that's what's happened. Otherwise it's not it's not fun radio trauma exactly. So let's let's just go ahead and get in now. Over here, we've got the dial which I'm going to set back to uh early seventeenth century. You know, I don't know how it knows where I wanted to go. It just does. But when is really tricky. All right, let's just hit the button. Here here we are.

It's a glorious and smelly So I want to introduce you to Johann Baptista van Helmont, who is the first person to describe hydrogen as a gas, and not only that, he's the first person to come up with the word gas to describe substances that have the qualities of a gas. He was thinking of stuff that is heavier than air, or misty, or he was just trying to come up with like a collective noun to call this stuff. He

proposed gas, and it's stuck. So he goes on to make some more observation which in a few decades get picked up by another person of philosopher, A natural philosopher, and we'll chat about him. His name is Robert Boyle. So between Robert Boyle and Johan we have in sixteen fifty Serteodor Turk with the men May yearn which I know I've absolutely butchered based Swiss, so so I'm sure he's fine with it. Yeah, They the Swiss have a beautiful way with words that escapes the physical contortions my

mouth can go through. So, but he produced hydrogen and he called it inflammable air by combining iron with sulfuric acid. Now, hydrogen is found in a lot of different compounds, including all the acids, So if you are able to combine it with other stuff, usually that that reaction you get by introducing an element into acid will release the hydrogen exactly. Now, sixteen seventy one we get to that Irish philosopher I

had mentioned, Robert Boyle. Now he experimented with producing hydrogen as well, and he was of the New philosophy movement. This was a really interesting movement. It combined observations and experimentation with logical thinking to understand the world around him. So this is sort of a proto scientist movement. It's before we really had the formal sciences. We this is

when alchemy was starting to transform into chemistry. Right. We had people who had made observations and calculations on things like physics, but it's now starting to actually take form into the sciences as we know them today. So he produced hydrogen by combining iron and various assets, and that's how he started to take a look at this hydrogen gas. And he was he was pretty pretty intelligent. He noticed that a gas volume varies inversely with pressure, hence Boil's law. Yeah,

we named it after after him. He also believed in alchemy and transmutation, so he didn't get everything right. You know, lots of people today still believe in alchemy and transmutation, so well, will leave that for now. But yes, Boil, he did a lot of work, and a lot of his work inspired other people. So over the next several decades, lots of different philosophers and then later chemists and scientists

began to experiment with hydrogen gas. They didn't really give it a name yet, but they knew that the stuff would blow up if you exposed it to flame, so they began to really study it further until we get to seventeen sixty six, and now we get to go to England, because that's where Henry Cavendish was and he was the first to recognize hydrogen as a distinct substance. And he was also the first to describe the composition of water. You know, before that, everyone just said it's wet,

and if it gets cold, it gets hard. That's that was pretty much it. If it gets really hot, it gets cloudy, that's you know, just that's where we were with science until Cavendish came along. I might be exaggerating a little, but he absolutely loved learning for learning, saying he wasn't actually a scientist per se though as he no, not really, I mean he was. He was more like just obsessed. He was one of the wealthiest men in all of Europe. He had inherited a crazy sum of money,

and he chose to live very frugally in London. He wasn't interested in the trappings of wealth. He wasn't interested in ostentation. He was actually, according to one thing I read, the only reason we even have a sketch of him is because an artist surreptitiously drew one while at a gathering, a small private gathering at his house because he didn't. He didn't you know, want he didn't. He didn't sit for a portrait. He was introvert, super introvert, and he

didn't really publish most of his work. He published some of it, but not all of it, because he wasn't really interested in that. He know, he just wanted to know how the world works. He was just fascinated with learning. He wasn't not necessarily as fascinated with teaching, but he was definitely fascinated with learning. I want someone to make a awkward action here a movie about this guy. Yeah. I have a feeling that we have to invent a lot of of facts about his life, which makes it

even better. Yeah, that's what movies generally do. Anyway, I'd be less offended if I knew less about the history of the actual guy. So yeah, I think Henry Cavendish Supervillain would be an awesome movie. So I'll get to work on that. Yes, all right, then we moved to seventeen eighty three, when Jacques Charles makes his first light in his balloon La Charliere, which used hydrogen as it's

a lifting agent because hydrogen is lighter than atmosphere. So if you get enough of it together, the buoyancy will counteract gravity and then you'll float right off the ground. Go up. Yeah. Meanwhile, in eighteen hundred, William Nicholson and Anthony Carlyle described the process of electrolysis, in which electricity is applied to water to break its molecules down into their constituents, being oxygen and hydrogen. This will become important later, yeah,

but just understanding that. Hey, this process where hydrogen and oxygen gets together to make water is reversible if you just pour energy into it. That's pretty cool. Eighteen or six we have Francois Isaac de Rivaz, a Swiss inventor. He built the de Revaz engine. And again I apologize if I'm absolutely butchering that, but this was the first internal combustion engine to use hydrogen and oxygen as a fuel. It would be nearly sixty five years before you get

the first gas lean powered internal combustion engine. So actually, hydrogen combustible engines predate gas, yeah by quite a bit. So you know, we've talked a lot about how electric cars are older than you think, so are hydrogen combustion engine cars. So that's kind of cool. Then in eighteen twenty we have the Reverend W. Cecil who writes a

paper and I love this title. Here we go on the application of hydrogen gas to produce a moving power and machinery with a description of an engine which is moved by pressure of the atmosphere upon a vacuum caused by explosions of hydrogen gas and atmospheric air. I think it's a sinct pretty much. You've read the whole article just by the title. But yeah, he proposed an engine and using hydrogen as the combustible material. But it's a different style of combustion engine than what we see today.

So his design involved having a chamber that you would fill with hydrogen plus regular old air, and it would be connected to a valve so that you could insert this stuff but it wouldn't escape back out. Uh. And then the you would put a flame in there, and then you have the valve switched so it would allow it to escape again. Right, you put the flame in.

This causes the gas to expand rapidly. Uh. And normally in our combustion engines we used as a pushing force, but at this case, the the piston in this chamber is all the way out already, so it can't be pushed further out, so he's not using as a pushing force. Instead, once that guest starts to cool and is released, it starts to shrink down. It's not and he's not letting more air in there to replace it, and the valve is closed, so it's pulling the piston back in in

that vacuum that's created in the chamber exactly. It's a partial vacuum and imperfect vacuum, and that creates an area of low pressure. That low pressure pulls on the piston, which then moves to the other end of the combustion chamber. So you're using this vacuum engine. Now. It worked, but uh, it's not really practical, So this particular design wasn't widely implemented, but it does in fact work. The principles are all sound.

So then you had a lot more experimentation following with hydrogen, which included everything from inventors to chemists to physicists and regular old crazy people and all of this is leading up to some pretty cool stuff, including the first fuel cell, and that wraps up part one of how hydrogen fuel works. Next week we will have um let me chip my

nose oh part two? Hey how about that? So, if you have any suggestions for topics I should cover on future episodes of tech Stuff, or maybe there's a topic that we have covered that is in sore need of an update, let me know. The best way to do that is to pop on over to Twitter. Our handle is text stuff H s W and I'll talk to you again really soon. Text Stuff is an I Heart

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