Rosemary Barnes: Welcome to engineering with
Rosie. In today's video I'm taking a tour of Green Hydrogen Systems. They are a Danish company who
make electrolyzers. their customers then use the electrolyzers to split water into hydrogen and
oxygen molecules. If you use green electricity to power the electrolyzer then we call it green
hydrogen, a topic that has generated a lot of excitement, but also a lot of skepticism recently,
so I wanted to know what you guys thought. And before this video, I asked you all to tell me what
questions you had about electrolyzers. In total, I got about 50 questions, so I was not able to cover
them on this video, I narrowed it down to about 20 questions that I asked Kasper Therkildsen, senior
development manager at Green Hydrogen Systems. And he also showed me one of their electrolyzers, so I
could get a good look at the equipment. And I will show that to you too. Unknown: What have we got here? Kasper: We've got a beaker, we've got a beaker
with some water and two metal plates, and then we put some wires on them. And then we turn on the
electricity. And now we see the bubbles forming. And that's hydrogen, hydrogen and oxygen. So
hydrogen comes out one side and oxygen out the other. Yes. So hydrogen was formed on the cathode and
oxygen on the anode. Okay, so positive and negative, Rosemary Barnes: I guess that makes it easy to
separate them Kasper: very well. And typically, we put in a
separator in between here. We can, you know, direc it in different channels. Rosemary Barnes: What kinds of metals Kasper: this here is just a nickel. So nickel is a
very good material for this Rosemary Barnes: and the membrane? Kasper: Yeah, so it's really a piece of plastic.
So actually, it's not a membrane, it's a diaphragm. So you don't see on this scale here.
But if you look in a microscope or electron microscope, you'll see that there's really tiny
pores in there around one micron or smaller. Rosemary Barnes: Okay, so the gas can't fit
through them. No, the bubbles can't go through. Kasper: Yeah, but but the liquid can we do alkaline water electrolysis, it means the
environment is very alkaline. We can actually see if we add more potassium hydroxide, you see, the
voltage now is around nine volts. And if we add a bit more, the voltage drops, because we're making
the water a much better conducter. And that's why we add it. Tthe downside is, of course, it's very
corrosive. So we cannot use any metal we want. And the water that's just, you know, Rosemary Barnes: the same water that we're
drinking. Yeah. Basically, you can run the reaction, just
with water. It was running just with water. Everybody can make hydrogen. Easy. You just need
two plates of metal and some electricity. And that's how simple it is. Kasper: The conductivity of water is bad. So that'
why we add something that makes the condu tivity better so the ions can move faster from
ne side to the other. That's why the voltage goe down. If you look at this, you can also see if
you look at the voltage if you move our electro es closer, and you see the voltage dropping, a
d it's simply because the resistance gets down b cause the path changes. So when you have bigger
distance, then the resistance goes up. and the vol age goes up. Rosemary Barnes: What does the voltage have to do
ith the amount of hydrogen that's produced? Kasper: It has... the voltage has nothing to do
with the amount of hydrogen it's the voltage times the current that gives you the power. So when you
want as little power as possible, when the voltage drops, you use less power, but the amount of
hydrogen stays the same, the current determines it, so for each electron
you put in there, you you form one, hydrogen, two electrons, you form one hydrogen molecule, it's a
matter of making it bigger and packing these electrodes very closely together in order to, you
know, get as much hydrogen produced in a small footprint as possible. For us, it's really about the material abundance.
So if you go to look at PEM electrolysis, so let's call it polymer electrolyte membrane, or proton
exchange membrane, uses a membrane, and then they have typically Iridium and platinum as their
catalysts, and especially Iridium. It's very scarce and platinum it's also quite expensive. So
if we're looking into the market sizes projected now it's just just not not enough iridium out
there. But but I mean absolutely certain that n the future you will have alkaline water elect
olysis and you will have PEM electrolysis, and y u will have SOEC so solid oxide elect
olysis. Rosemary Barnes: So what does one megawatt of
electrolyzer cost or? What? What can you tell me? Sure, Kasper: I mean, so we're talking very much about
levelized cost of hydrogen. So we are inspired by the wind power industries. So like for a kilo of hydrogen... yes, what do you pay? And that's, of course, very
dependent on where you get your electricity from. and how much you pay for that. But you have a, you
know, a capex path. So an investment part of your electrolyzer, but you also have, of course, your
maintenance and expenses in there as well. and f r us, that's the key number somehow, but you and y
u can have systems where you have a very low capex and then of course, people say "ah well we have
very low capex," but the price of hydrogen is no that low. Because if your efficiency is not high,
then it's, it's you don't gain anything by havin a low capex. Rosemary Barnes: Yeah. Okay. Kasper: So it's not an easy question to answer. Rosemary Barnes: So, the electrolysis splits the
water into hydrogen and oxygen and everyone is mad keen on the hydrogen part of it, what's happening
to the oxygen? Kasper: In most cases just goes to the air, you
have a few, very few use cases where people are in need of oxygen. and where it makes sense to
utilize it. But but it's very, very rare It's basically just a lot of electrodes with
diaphragms in between, packed very closely together. and then they call that a stack because
they're stacked on top of each other. And it looks like this somehow. For each two ridges, you
have one electrode, so one electrode, one diaphragm, one electrode, one diaphragm, one
electrode one diaphragm. So the water basically goes into these tanks we have up here and these
here are separators so you have the potassium hydroxide pumping around, it goes up here and then
you separate the gas from the liquid and then it goes through a lot of processing afterwards to get
the hydrogen clean. so that's basically it you have some pumps down
the pumping the lye, the water with the potassium hydroxide around and a heat exhanger because this
process heats up. So we need to remove the heat. So this is a small module is put in a container as
you see so it comes complete. so basically you just need to plug into the power grid. and we have
power supplies next door here you have the water cleaning system in there as well. And all the
controls so you can just plug it in and then produce hydrogen. we have reverse osmosis but you can use seawater
if you want. and desalinate that. so you can actually use the excess heat from the system to go
into desalination. Rosemary Barnes: Alright, so inland though, in the
desert inland, you couldn't work there. Kasper: You need water or else you can't produce
hydrogen. I mean, this is water splitting, so if you if don't have any water, it's not gonna work. This is around 200 kilowatts. But if we extend the
stack, we can get it up to these 430. Rosemary Barnes: And so then that makes for like,
5 kilos an hour or something? Probably around four. Okay, one of the possibilities of hydrogen that
seems to have really captured people's imaginations is that we could be using
electrolysis to convert surplus renewable electricity into hydrogen. And then some people
even think that will then convert that back into electricity as a major component of future
electricity grids. Do Green Hydrogen Systems see this kind of application as a major opportunity
for them? And if not that, then what kinds of applications are they expecting? It's going to be used for transportation and
industrial purposes and maybe in some cases also for for heating process heating. Yeah. Okay. And only convert it back to electricity, if you
absolutely must somehow, because you pay a penalty as you're saying. Kasper: There's a natural hierarchy somehow, you
should use electricity as electricity for all the cases you can? Of course, that's obvious. But when
you cannot use electricity, you need to convert it to something else. And then hydrogen is a very
good candidate. Yeah. And then you can convert it even further if you want to liquid fuels or
ammonia or methanol. So it, of course, use electricity for what you can use electricity for.
Always make the simple solution. And but I mean, it's also worth noting that if you look to the
North Sea, for instance, the wind power potential out there is just enormous. And the electricity
grids in the countries around cannot support that amount of electricity. So you can put up maybe 250
gigawatts of wind turbines out there. But the electricity grid in Denmark or Germany,
Netherlands and, and Great Britain, can't support that amount of electricity. So in order to utilize
that resource, you have to convert it into something else. Could be hydrogen could be
ammonia. Or if you have a CO2 source, it could be methanol or anything else. It's from thermodynamics basically, and you
convert it to a cell voltage, okay. So you need 1.23 volts, to split water. But the reaction also
requires an amount of heat. So if we convert that to electric voltage too then we need to be around
1.48 volts, that's what we call the thermoneutral potential. So that means that you have supplied
the electrical energy needed and heat needed in order to drive this process. So and as you saw
earlier, that the voltages we had in a beaker like that was around five volts or even more, so
there's a quite a big gap a big gap from that. And all that's the waste, the inefficiency. Yes. And that just generates excess heat. Okay. Rosemary Barnes: So the efficiency, that Green
Hydrogen Systems state in their brochure for total system load is 76.5%. But how much room is there
to improve on this? Could you get like another 10%? Could we get at about 80% efficiency? Kasper: You can get to quite high. So 85, fairly
easy. I mean, we know where we can improve? Yes. And it
is very much on the stack level. But of course right now we have some conversion losses for AC DC
conversion as well, which can be improved quite dramatically. Yeah. And that's just easy, to do
that. But But over time, of course, you can play all these tricks to reduce the resistances and
increase the catalytic efficiency and you go up in temperature, then everything gets more efficient. And that will bring us very close to these 1.48
volts. Rosemary Barnes: In a number of years. Is that like five years, 20 years? Five to 10 years Kasper: 10 years back, and nobody believed that
the price of electricity would be where it is now from renewable sources. Nobody predicted that. And
we'll see the same with hydrogen. You know, once things get rolling, it's gonna be tremendous. Rosemary Barnes: Well, that was cool. I was really
excited to see a real life electrolyzer plus the tabletop demonstration of electrolysis and now
that I've seen how easy it is, I feel like I could start my own electrolyzer company. Now, obviously,
there's a lot more to electrolysis than the basic principle, which Kasper showed me on the table top
and it's been known and exploited, for well over a century already. The main challenges have to do
with scaling it all up very fast and bringing the cost down also very fast. Now, cost was the most
common viewer question that I had, and I was unfortunately not able to get a really satisfying
answer on this. Basically, because there are just so many variables involved beyond the electrolyzer
itself. I think I'm going to save that question for another video. So there were also a lot of
other questions that I couldn't get to today either, like transport and storage and E fuels.
I'm going to keep them on my list for future videos. But if there is a topic that you're
especially keen to hear about, then please let me know in the comments, I try to prioritize the
videos that people are most interested to see. So if you tell me then you're more likely to get the
video that you want sooner. Thanks for joining me on this tour today. I hope
you learned as much as I did, which was really a lot. Don't forget to check out my other videos on
hydrogen and other green energy technologies and subscribe and turn on notifications so you'll see
when the next This one is released. I'll see you in the next video.
