Premiere: ‘Inflection Point’ podcast explores history of green hydrogen

The new podcast Inflection Point leans on C&EN’s 100-year archive to trace headline topics in science today back to their disparate and surprising roots. In each episode, we explore three lesser-known moments in science history that ultimately led us to current-day breakthroughs. With help from expert C&EN reporters, this new show examines how discoveries from our past have shaped our present and will change our future.

In our first episode, hosts David Anderson and Gina Vitale travel back in time to relive three events that ultimately led to the development of green hydrogen. They also bring in C&EN reporter Craig Bettenhausen to analyze how this emerging technology could shape our future.

Subscribe to Inflection Point now on Apple Podcasts, Spotify, or wherever you get your podcasts.

The following is a transcript of episode 1 of Inflection Point. Interviews have been edited for length and clarity.

David Anderson: In 1789, two Dutch scientists invent electrolysis using static electricity.

Then, more than 100 years later, across the Atlantic Ocean, researchers at Bell Labs develop the first practical solar cell.

And in 1975, two scientists in New Jersey researching supersonic jet exhaust create a climate model that accurately predicts the warming of our planet to this very day.

Independent of each other, these breakthroughs weave their way through history and meet up at one point in time: This moment. Right now.

Gina Vitale: [sort of a record-scratch interruption] David—um, sorry—what are you talking about right now? How are these three historical events related to each other?

David: They’re inflection points!

Gina: Inflection points of what?

David: These three discoveries—electrolysis, solar cells, and climate modeling—all needed to take place in order for us to be able to develop an important new technology that is the focus of many conversations today: green hydrogen.

Gina: David, how did these three very separate things lead us to green hydrogen?

David: I’m going to tell you.

[Music break]

Gina: This is Inflection Point.

David: Spanning a century of reporting from C&EN, this new podcast traces discoveries from our past—

Gina: —to how they shape our present—

David: —and will change our future.

Gina: I’m Gina Vitale.

David: And I’m David Anderson.

Gina: David, let’s make sure we’re on the same page here.

David: Sure.

Gina: We’re talking about green hydrogen, as in hydrogen that is produced by splitting water atoms using renewable electricity.

David: Bingo.

Gina: And green hydrogen is a big deal today because it is basically a fuel source that we can produce without emitting carbon. So it’s really green, as in ecofriendly. Climate friendly.

David: Yep.

Gina: And you’re telling me that these three random events in history are all related to green hydrogen in some way?

David: Exactly! All right, great. I’m so glad you get it.

Gina: I don’t get it.

David: OK . . .

Gina: Like you said one of these events took place in 1789—how could that possibly be related to green hydrogen?

David: Well, I’ll tell you. Let’s go back to 1789.

[Tape rewinding sound effect]

Gina: What was that noise? Did we just go back in time?

David: Kinda cool right? That’s the inflection point sound, not a big deal. I made it myself, but anyway, this one has to do with something called water electrolysis, which I’m sure you’re aware of.

Gina: Yeah, the process of separating out water into its component parts: hydrogen and oxygen. Then you can take those two elements and recombine them. Energy is released, and water is created. This way, hydrogen can be used as a fuel as long as it’s combined with oxygen.

David: So the story of electrolysis: if you want the real history, you got to dig deep. Because if you just Google “history of electrolysis,” you would come across two British guys, Anthony Carlisle and William Nicholson.

Gina: Old Carlisle and Nicholson, OK.

David: So the often-repeated story is that these two guys, in 1800, got wind of a wonderful new invention, the voltaic pile, which is basically the first modern battery. They found out about this new technology and immediately put it to work inventing electrolysis. They ran a current through water and created hydrogen and oxygen. And this incredible discovery set the foundation for all these amazing things to come. Except—

Gina: Except?

David: It’s lies!

Gina: It’s lies?

David: It’s all lies. It’s lies, Gina.

Gina: Were you reading the AI overview?

David: I mean, maybe lies is kind of a strong word, but it’s not really the whole truth.

Gina: OK.

David: In fact, in 1789—more than a decade before Carlisle and Nicholson—there were two Dutch fellers who actually discovered electrolysis, and they did it without a battery.

Gina: Without a battery. OK.

David: Our two Dutch scientists, if you really want to call them that, were actually a merchant and a medical doctor. Their names were Adriaan Paets van Troostwijk and Johan Rudolph Deiman.

Gina: They must have used some kind of energy, right? You need some energy source to force the water molecules apart.

David: Yeah. And I will get into that in a second. First, I kind of want to give you a rundown of how exactly they did this, right, because we think of electrolysis in a totally different way now. But when they were inventing it, when they were doing it for the first time, they kind of had to improvise a little bit.

Gina: I guess if nobody had ever done electrolysis before, they probably had to do some wonky stuff to figure it out.

David: So in their lab, basically, they set up a giant glass tank, filled that with water. And then they took a glass cup. And then they stuck that in the water and submerged it and turned it upside down. So there's water trapped inside the cup.

Gina: OK. Upside-down cup full of water in a tank. I'm following you so far.

David: They ran some wires through that cup. Ran a current through those wires—

Gina: OK.

David: —and the wires started bubbling. The electrolysis process started. So two gases were being created, right? The hydrogen and the oxygen.

Gina: Got it.

David: And so, inside that cup, those gases are kind of bubbling and rising to the top of the cup. And they're getting trapped there. Eventually, so much gas is built up in there, one of the wires isn't touching water anymore. So it can't do electrolysis.

Gina: Ooh, I think I know where we’re going with this.

David: And it sparks. And you've got oxygen and hydrogen in this enclosed space with a spark, so it basically causes an explosion.

Gina: Love a good explosion.

David: And that explosion really rapidly recombines those two elements back into water, so they could just watch, from the outside, this process happen over and over and over again, where the electrolysis creates gas, the gas builds up, and spark—explosion—and then the glass is back to being full of water.

Gina: So it just keeps going in a cycle.

David: Yeah. They could just keep going. And their findings were published widely, all over the world, in French, German, and of course Dutch. And in English in Great Britain. In fact, in 1797, a British scientific journal called Philosophical Transactions, which still exists—

Gina: Hmm.

David: —wrote that the experiment, quote:

Nick Ishmael-Perkins: “must be admitted by the most rigorous reasoner, to be demonstrative that hydrogen and oxygen gas were produced by passing electric discharges through water.”

Gina: So basically, it happened. You’re saying there is some published record showing that the two Dutch scientists did do electrolysis before those other guys.

David: It’s definitely possible that Nicholson and Carlisle, the English guys from earlier, had heard about this process when they replicated it 11 years later with their newfangled battery tech, the voltaic pile.

Gina: So where did the Dutch scientists get the current to run their experiment?

David: Basically, they're using the same tech as, you know, Doctor Frankenstein. What they used was called an electrostatic generator, and it was a big glass disk that they spun around by hand that would create static electricity. So the first electrolysis experiment was actually just generated by hand.

Gina: Wow. OK, so we needed to invent electrolysis so that we could later split hydrogen and oxygen in water atoms. That’s the inflection point, right? Because in order to produce green hydrogen, we have to be able to produce hydrogen in the first place.

David: Totally, yeah.

Gina: And nothing has changed? We’re still doing it like we did it in 1789?

David: I hope not. I think that they've probably gotten rid of the electrostatic generators and things like that.

Gina: The hand crank?

David: I don't think they're hand-cranking the electricity for this nowadays, but to be honest, I actually don't really know. Fortunately, I don’t have to answer that question; we have a senior editor here at C&EN who knows all about green hydrogen.

Craig Bettenhausen: I’m Craig Bettenhausen. I have somehow become C&EN’s hydrogen guy because it's the overlap of my coverage of sustainability and decarbonization, and industrial gases happen to be another part of my beat. So it's a real nice lineup of those two interests.

David: So basically, if anyone knows what’s changed in the last 200 years of electrolysis tech, it’s him.

Craig: A lot of the core principles are the same. So if you took those Dutch scientists, brought them forward into the future [to] today, they'd recognize a lot of what was going on. The differences are, one thing, the scale. They were working at a bench scale, and these things are now the size of school buses and things like that. And also just the scale of it as an economic force. It's no longer just a lab toy. These are being done at very large commercial scales, and bigger every year. Once you got into the nitty-gritty of the machines themselves, we're using a lot of different materials. The electrodes, the membranes to separate the gases and to control the reactions. Those are very different. Now, they are elaborations and improvements on some of these original experiments. So even with that, your Dutch scientists would still, I think, be able to follow what's going on.

Gina: Got it. So electrolysis has gotten better and bigger. And in the case of producing green hydrogen specifically, these big old electrolysis machines are powered by energy that comes from renewable sources. Right?

David: Kind of, yeah.

Gina: Kind of?

David: It doesn't always come, like, straight from the renewable resources. Not even most of the time.

Gina: Not—

David: Most of the time it probably doesn’t.

Gina: Not even—what do you mean? What do you mean, not even most of the time?

David: I am so excited about our next inflection point!

[Inflection Point sound effect]

Gina: Wait, wait, wait—so we’re not using green energy to power green hydrogen?

David: Uh, not technically, if you want to get into the specifics of it.

Gina: Let’s get into the specifics of it. I would like to know the specifics of it.

David: Well, I think first we can travel back to the interesting year of 1954. Marilyn Monroe married Joe DiMaggio—

Gina: OK.

David: The US was testing new hydrogen bombs in the Pacific.

Gina: Sure.

David: And somewhere inside a sprawling laboratory complex in New Jersey, photovoltaic technology—basically the world’s first solar panel—was born. Scientists at Bell Labs created a solar cell.

Gina: OK, so the inflection point is that we discover solar cell technology in the 1950s, which we now use to harness the green energy that powers green hydrogen. Right?!

David: You know, this technology is super fascinating.

Gina: Well, that’s not really what I was asking.

David: You see, the basic idea of converting solar energy into electricity had already been demonstrated—

Gina: OK, wait, David, I’m not asking about when exactly we came up with the concept of solar cell technology.

David: Such an interesting story.

Gina: I want to know how we power green hydrogen. Is it not through green energy?

David: No, I think usually when we talk about green hydrogen, it’s probably powered by [coughs] fossil fuels. Fossil fuels.

Gina: I know, I know that you didn’t just say “fossil fuels,” because that can’t possibly be right. Because we just told listeners at the beginning that it’s from renewable energy, which is not fossil fuels.

David: I am starting to feel a little under siege. I am just going to toss it over to Craig. Craig?

Craig: Yeah. It’s uncomfortable to think about if you’re really wanting that green product. But the fact is, most of these things are plugged in to the electrical grid. And the grid is a mix. It's a mix of fossil fuels, nuclear power, and renewables. And in the US, on average, 60% of the grid is powered by fossil fuels. It's a mixture of coal and natural gas. And only 21% of the available energy is from renewables, with the remaining 19% coming from nuclear.

And it also depends on where you are geographically. Not everybody has renewables near them or nuclear near them. So the way that it works then, if you're going to buy these renewable energy credits, like you might literally be plugged into a coal plant, but then the coal plant company has to pay and subsidize a solar farm, you know, way out in the hills. And so over the long term especially, but even in the short term, buying those renewable energy credits does result in the mix on the grid having more renewables.

So if you imagine that energy, the energy coming into your electrolyzer might be coming from a coal plant, but overall, more of the energy on the grid is coming from renewables by way of these credits.

Gina: OK, so just let me get this straight—it has to be kind of tied to renewable energy, but the power for the electrolysis does not have to come directly from renewable energy?

Craig: Yeah.

David: Inflection Point will be right back after this break.

[break]

David: All right Gina, where were we?

Gina: Let’s get back to your inflection point, the solar cells. I’m guessing you chose that because most renewable energy that we do have on our grid is solar based?

David: Don’t hate me.

Gina: What?

David: It’s actually wind.

Gina: It’s wind?

David: Most green energy is; it comes from wind. But we can’t have a windmill inflection point; that would have to start like 4,000 years ago.

Gina: Oh, god.

David: We’d need to start a whole new podcast. I’m game, if you want. A windmill history podcast.

Gina: The windmill history podcast?

David: Yeah.

Gina: Well, maybe let’s get Inflection Point out the door first. Which reminds me, how does supersonic jet exhaust in 1975 fit into all this?

David: That wasn’t just immediately obvious to you?

Gina: The jet exhaust?

David: All right, fine, twist my arm. I will tell you the story of Syukuro Manabe. He’s a physicist who in 1958 left Japan to join a US Weather Service project that aimed to create a computer model to study Earth's climate. So imagine the computers of the time, the ’50s, ’60s, and ’70s. Computers were these giant, really slow, not efficient machines.

Gina: Sure.

David: Manabe and another scientist, Joseph Smagorinsky, were charged with trying to figure out how to predict changes in weather and climate.

Gina: When do the supersonic jets come into play?

David: I promise, I promise this is not a bait and switch. We will talk about the supersonic jets. I promise.

Gina: You’re on thin ice, David.

David: I swear, the supersonic jets are coming. But I do want to acknowledge the genius of these two guys. They had to simplify virtually everything about a climate of an entire planet, and they had to do it with these old computers.

Gina: OK, how did they do that?

David: One thing they did that I thought was really cool is that instead of modeling every single detail of an atmosphere, or at least trying to, they broke it up into layers. Kind of like how if you take a slice of cake, you get to see representative layers of that cake through just one slice, instead of maybe analyzing every single crumb of that cake.

Gina: Hmm, OK, that’s interesting.

David: So in the ’70s, they realized that their model could accurately predict how human activities might change our climate. And, oddly enough, their first experiment wasn’t even about carbon dioxide. It was about—

Gina and David together: Supersonic jets!

David: It was about the supersonic jets.

Gina: Yes!

David: And they were measuring water vapor.

Gina: Why?

David: They were worried because in the course of flying supersonic jets, they fly really high in the atmosphere, not like regular passenger airlines.

Gina: Oh, interesting. I don’t think I knew that.

David: So part of their exhaust includes water vapor. And most water vapor in the lower atmosphere just condenses into clouds and rain and falls to the Earth.

Gina: Sure, that makes sense.

David: But in the stratosphere, it’s much drier and colder. Water vapor doesn’t really easily condense or leave. So any water vapor released that gets released up there could linger for a long time and potentially warm the planet. But of course, supersonic jets aren’t very common anymore—they were hardly even common back in the day—but they thought that in the future maybe supersonic jets would just be everywhere.

Gina: Huh. RIP [rest in peace] supersonic jets. So how does this all come back to green hydrogen?

David: So while they were exploring this jet exhaust, they wondered, Hey, maybe we could plug in a couple other variables here too. And they started looking into CO₂ [carbon dioxide]. In 1975, they published a paper that calculated what would happen if CO₂ levels doubled preindustrial levels. They predicted a temperature increase of 2.36 °C, which is very close to today’s estimate—which we calculate using supercomputers, by the way—of 3 °C.

Gina: Hmm.

David: 2.36 versus 3 °C.

Gina: So we were pretty close.

David: Very close.

Gina: So I’m guessing this is part of what started setting off alarm bells about carbon emissions.

David: Definitely think that got the wheels rolling a little bit. And to be clear, humans haven’t doubled the CO₂ in the atmosphere yet. But by current estimates, we’re on track to do that by the end of this century. So for his part in all this, one of the scientists that I mentioned earlier, Manabe, shared the Nobel Prize in Physics in 2021.

Gina: So with all the modeling showing how the Earth’s temperature would increase, people got inspired to find more ecofriendly fuel sources, like green hydrogen.

David: Exactly. So now you see, all of these inflection points—electrolysis, solar cells, climate modeling—lead us to green hydrogen! Which of course is a bastion of perfect, carbon-free fuel.

Gina: Well, I don’t know about perfect. There’s the whole fossil fuel credits thing.

David: Yeah, alright fair enough, that’s a little weird.

Gina: And we’re not even really using green hydrogen that much.

David: What? That can’t be right.

Gina: Here’s Craig.

Craig: Not a lot of green hydrogen is actually used today. And that's for a couple of reasons. For one thing, it's just, it's still an expensive way to make hydrogen. They're working on that really hard, scientists and researchers and engineers, but it's expensive, and there's usually cheaper ways to get hydrogen if you need it. There also is a limited amount of renewables on the grid. And so a lot of times, the renewables are prioritized for more existing baseload needs—you know, heat and light and data centers and things like that.

David: Let me just try to get this straight. All these inflection points come together to make this really cool technology that we barely use? Do I have that right?

Gina: Well, we may not use it a lot yet, but it’s constantly growing! And it’s helped inspire all kinds of other ecofriendly hydrogen production strategies.

Craig: So we talk about green hydrogen most. It's the fastest growing, but you have all these other colors of hydrogen that are competing and developing. Blue hydrogen is at a larger scale. And that means that you're making hydrogen from methane, from fossil fuels. But you're capturing the carbon dioxide that comes out of that process and sequestering it or using it for something. So that's blue hydrogen.

But there's all these other colors too. My favorite is turquoise hydrogen, where you're still, they’re starting from methane, but instead you change the reaction to get your hydrogen. So instead of getting carbon dioxide as your by-product, you get solid carbon. You get graphite or carbon nanotubes, depending on the technology, which is great because then you don't have carbon dioxide gas to deal with at all. You just have, like, a bucket of black powder, which is much easier to handle.

If you are making electrolytic hydrogen with nuclear power, that gets to be called pink hydrogen. And then there’s also the idea that you can inject microbes into spent oil fields, who will then eat the fossil fuels remaining in there and spit out hydrogen that you can then collect. And depending on who you ask, one of those is white and one of those is gold, and they can never agree. The rainbow is helpful when you’re trying to quickly describe what kind of technology you’re developing.

Gina: So without those three inflection points you found, we wouldn’t have the hydrogen rainbow.

David: Fair enough. OK, that makes up for it. We've got pink hydrogen; I'm happy.

Gina: I think I like turquoise hydrogen. I like that you can get solid carbon out of it.

David: Well, I tell you what, Gina, you are really going to like the next set of inflection points.

Gina: Oh yeah? What are they?

David: Don’t laugh, these ones are kind of obvious, I think you’ll basically understand the subject of the next podcast immediately, but—

Gina: OK.

David: They are atomic bombs, aquarium filters, and Gore-Tex. So I’m sure you know exactly what I’m talking about.

Gina: I don’t think it’s as obvious as you think it is.

David: Well, you’ll have to tune into the next episode to find out.

Gina: Would I tune in?

David: OK, you got me there. I’ll just say that everything will be revealed in the next episode.

Gina: Well, I’m looking forward to it.

Gina: Inflection Point is a podcast project from Chemical & Engineering News.

David: Chemical & Engineering News is the official news outlet of the American Chemical Society.

Gina: Music by Kirk Ohnstad and Shutterstock.

David: Research help from Alex Tullo.

Gina: Additional voice acting from Nick Ishmael-Perkins.

David: Written, produced, and hosted by Gina Vitale and David Anderson.

Gina: Thanks for listening!

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Premiere: ‘Inflection Point’ podcast explores history of green hydrogen

This new technology hinges on 3 historical breakthroughs

by David Anderson , Gina Vitale

March 25, 2025

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Premiere: ‘Inflection Point’ podcast explores history of green hydrogen

This new technology hinges on 3 historical breakthroughs

by David Anderson , Gina Vitale

March 25, 2025

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