In part 2 describing the Fuel Cell part of the System, I said part 3 would be about the battery backup system necessary to maintain the power from the panels to the electrolyser, the latter being the hydrogen generation component in the solar hydrogen power chain.
CIMC ENRIC supply professional and honest service.
But the battery backup unit is such a standalone self documented item, it doesn’t warrant a whole part to itself, and besides, it isn’t itself a hydrogen component. Readers would not be learning much about sourcing hydrogen equipment by reading about the battery backup. Further as explained in part 2, the battery backup is intended as a temporary measure. It is warranted whilst it remains competitive in price, whilst that still matters in the for-profit (Pre-Kardashev Scenario — See part 2 for clarification). Further, battery backup technology and how to apply it is already mature, literature on it is all around us. I only need to reference some of that in the next and final part of the detailed system design, covering the panels selection.
In contrast, the hydrogen storage part of the system, the stuff in this part, part 3, is probably the most controversial, in terms of how it has to work, relative to the other system elements. This is the part of hydrogen technology which seems to me to have suffered most due to misinformation, and subsequent lack of development, preventing it from becoming something directly comparable with fossil fuels in many ways, because actually if we know a little about hydrogen, it potentially trounces fossil fuels on every count.
As for batteries, well the writing has to be on the wall for all the plans to use those massively, when we realise the full potential of hydrogen (Sorry Elon)
So instead of covering the battery battery backup system, here we are going to cover the most controversial part of the hydrogen energy chain, hopefully removing much of the controversy.
The truth is we can’t even see the full potential beneficial value of widespread use of hydrogen. We won’t, and actually can’t, until we move to it.
But we do know some of the benefits, including creation of food (See “Solein”), filtration and circulation of both water and air, and the potential to create bio-friendly plastics. Further it works to directly fuel both internal combustion and electrically powered machines.
What I can see as someone deeply immersed in Engineering technology all my life to date, including in R&D roles, is that the pumping aspect of hydrogen appears to have been something severely underfunded and knee-capped at every turn, since most of the research done on it seems to have been funded and lead by fossil fuel based industries, which if they/we are honest, do not wish to cannibalise their existing business, by activating a fuel which potentially wipes the floor with all benefits that were thought to have been had by fossil fuels.
But in the end, the thing that matters most, as we are seeing, is our planet. Without that in good healthy working order, we are nothing, and money is nothing, because without real sustainable energy in money, there is no working economy. In fact there is not even any life, if we carry on as was. Of course it has to change for our survival, and the survival of all life, if nothing else.
I’ve explained elsewhere why profit directly relates exclusively to extracted energy and temperature rise, so won’t go into too much details again here.
Anyone wishing a quick primer on the fundamental economic argument driving the design should check part 2, it gives a quick rundown with links to futher information of how Kardashev Money, and the “Money-fuel tree” relates to the system under design.
In effect, we are building a money-fuel tree, but without the ability to generate cryptocurrency, though anyone can add that on for free, if banks and money issuers fail to “Step up”, to provide the financial side of the system solution, by failing to issue solar indexed stimulus ^^.
The point is that after construction of this system, all hydrogen generated which is not used by the microgrid is convertible to money, by being exchangeable for money, and the energy that goes into creating all of the hydrogen is for free per Joule / KWhr. The sun never asked anything in return for it, other than maybe we use it wisely (i.e. we should use it to create things, anything other than heat!).
OK now you’ve been given the reasons why, you are forewarned of what can only be called a development starved horror story, and a mess, of what we currently need to do, in the storage system, to put the most development handicapped part of the system to use, despite the handicapping. Remember this is the one part of the system that will, one day very soon in my own opinion, be rapidly developed to produce liquid hydrogen, bottle-able at moderate pressures and room temperature, using minimum non-recoverable energy, thus unlocking all the potential of hydrogen to be used to do far more than we ever did by fossil fuels, all at real benefit to the planet, the more put to use the better, none of it doing any damage.
For now the best trade-off that can be had between fossil fuels replaceability, and energy cost of pressurisation, resulting in still by far the most energy inefficient part of the system due to lack of development to date, is as follows:
At the input of the hydrogen storage system we need a pump, to pump the hydrogen from the electrolyser / drier combination to a form that is practically storable, and useable by outside parties who might use our excess fuel. This type of pump, approved for pumping hydrogen, as stands is only available in compressed air driven form. I believe this is most likely due to onerous safety standards which we can be sure will have been driven by utilities energy / fossil fueled interests to maximise the perceived safety hazards of hydrogen. I don’t see technical any reason a safety approved hermetically sealed brushless electrical motor driven pump, for example, could not be developed for this.
But we need to work with what is available, regardless of our instinct that here we are losing a lot of valuable energy to heat, unnecessarily. The resulting efficiency figures are horrendous, compared with established battery backup figures, for example.
The hydrogen pump specification selected is for this one, from Alibaba:
The pump at the heart of this rack assembly is described as a reciprocating pump.
More information on those is here:
We need the 700 bar version of the pump found, to fit with current pressure standards commonly in use (More on this when we get to the hydrogen tank specification)
The pump model we need is the highest pressure variant in the Technical paramaters section of that web page, model number GU-GTB-100.
A clip of the Pump Technical Parameters is shown below, GU-GTB-100 is the one in the bottom row.
We can see there the maximum flow rate that the pump can handle is given in NL (“Newton Litres”) per minute. NL is a pressure included flowrate, where the flowrate in Litres is modified by Newtons pressure. This is equivalent to Litres flow at atmospheric pressure, and becomes less volume at higher pressures.
The maximum production rate of the electrolyser is given as 500NL/hr, which is 500/60 = 8.33 NL/minute. So the pump can easily handle this.
When we consider the pump efficiency in more detail, as we have to for the System DMN model, the pump duty cycle, deduced by the relationship between the pump capacity, and the electrolyser output will be most useful.
Though it has to be admitted the need to drive the hydrogen pump by another pump looks like a horror story in terms of efficiency, what we must keep in mind is that every kg of hydrogen stored, is 33KWhrs less energy from the sun that will go to heating the planet, at least until the hydrogen is consumed. Imagine billions of people, all storing a few kg of hydrogen, and every vehicle including every aeroplane (thousands of kg per plane), storing lots more kgs of hydrogen — that is a lot of heat energy removed from the the environment.
This is very different from the heat energy discarded to the environment in all the processes of fossil fuel production, which are actually the opposite processes to above. In the “creation” of fossil fuels, we are actually reversing the process that nature did, over millions of years. This is not creation at all but actually the opposite. Nature converted all the energy captured from the sun, in fossil fuels, into something other than heat. The amount of energy taken from the sun by nature to do this is given by E=MC squared, where M is the mass of materials. We can say this about any materials in nature, they were all created, and continue to be created with the effect of reducing heat. By reversing that that action, inevitably we are releasing the vast majority of the energy used to create the materials back to heat.
The total heat energy returned to the environment by energy extraction is given by ((E=MC squared) minus what we put to use, minus the energy yielded as usable fuel, minus the energy in the pollution materials produced.
This was before we consumed the energy yielded. This has to be added to the unused energy of the heat of the sun, so its a double whammy. When we don’t use the energy of the sun, not only do we miss an opportunity to use energy that results in less heat, but we are forced also to do the work of extraction, which adds to the temperature impulse, because we have to get at least the energy we each need to metabolise, 150 or so Joules per second (150 Watts), 24/7, from somewhere.
Compare that with the case of our creation of hydrogen from solar energy, at any efficiency. We didn’t add any heat whatsoever per KWhr of energy put into hydrogen, which would not have been generated by the eneregy of the sun had it gone unused in any case.
Yes there is an energy cost in the kit we have to install here, but once this is installed, there is only the energy cost of maintenance remaining. Notice much of the resources in this kit are things that will become available from recycling, because if we are honest, this kit will replace a lot of utilities grid infrastructure. An awful lot of those pylons, overhead cables, substations, and of course power stations, will disappear, leaving an awful lot of materials to be recycled.
The mathematically positive energy rule of creation applies, however efficiently we did the conversion. Obviously if we can make improvements to efficiency, then we can accelerate rate of creation, and rate of temperature drop.
But low efficiences of creation are infinitely better than high efficiencies of destruction.
So it isn’t a fair comparison to compare the efficiency of solar energy with any other energy at all. Solar is the only mathematically positive energy, the only one added to Earth, the only one we can actually create with, so actually the only one that is sustainable. This is why we should have formally mathematically signed energy a long time ago, to make this clear, and to begin auditing one against the other.
Again fossil fueled / utilities energy profit driven interests and associated subsequent instruments like Occam’s razor, are most likely responsible for that omission.
But hey-ho, we have to work with what is on the table.
Even if we only get 10% efficiency, every kg of hydrogen created, is still creation, vs the actual destruction done by all the heat energy lost in the physical extraction and processing of fossil fuels. LNG might look good relative to other fossil fuels on paper, due to it having much less processing en route to consumer, but only until we realise that it too is a material, every gram of which when converted to energy has to add to heat impulse. Use of it can never be something that subtracts from heat impulse, like use of solar energy absolutely is.
This matters much more than efficiency, and actually it is this process of creation which creates economic product which is far more valuable than fossil fuels can ever be. Money, when it comes to represent solar energy, as it has to, will have strength never seen before. Inflation will become a thing of the past, when we accept it was always about the effective energy per token money, that was always what mattered, and still matters most to money.
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UPDATE — The following section extension on Pump Selection was added on 23/11/. Choice of pump changed, but performance specification is similar. Above information still relevant, reasoning is augmented rather than superseded. Original information is left basically as published.
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On quizzing TEREK about the efficiency of pump GU-GTB-100, they clarified that they would not recommend use of their pump for H2 pressure in excess of 350 bar.
Technically it would work, but they are concerned that the materials used in their pump could not be guaranteed for sustained high pressure H2.
I am glad, and to their credit, they were honest about this.
Risks of hazards of this kind are obviously not worth taking, especially in a potentially domestic environment.
So I had to spend a little (Actually a lot) more time, to search further for a suitable pump with the above experience and lesson learned; about limitations likely with probably most pumps in Alibaba, appearing to be capable of use for H2 at all the pressures listed.
I had to search for a pump that explicitly states in writing, with a guaranteed period of operation, that it is capable of handling hydrogen at 700 bar. The one found is guaranteed for a year’s operation at bar H2 pressure.
This is the pump found:
It obviously looks a lot different than the effectively racked unit of Terek. This looks more like just the pump within the Terek racked assembly with none of the connecting and manual controls or guages.
The technical details of whether or not it would be best to have this pump incorporated in a rack assembly like the Terek pump are left for later considerations. All we are really interested in right now, for the purposes of System Modeling, is whether or not this pump will do what we need, racked or otherwise.
It does appears to have everything needed, pressure switch etc, for use directly connected between tank and electrolyser. It is again air driven like the Terek pump.
The materials are specifically mentioned in the description of this pump as being suitable for high pressure H2, and separate pressure specifications are given for oxygen, hydrogen, and inert gas (Such as N2).
The pump is described as being constructed from stainless steel, but has options on seals, optimised for hydrogen if the pump is specified by the customer to be used for hydrogen.
The specifications are given in a completely different way than the Terek pump, we see far less detail on performance.
To be sure this pump is capable as a higher quality replacement of the Terek pump, we have to do some comparisons between the very differently presented specifications for each pump, to confirm that the newly specified pump will do what we worked out should have been possible with the Terek pump.
On searching the internet for more information on how to relate throughput flowrates to displacement specifications, we find a Haskel pump catalogue, which appears to have all the specifications for both flowrate and displacement for a more or less identical pump model.
The photographs in the Haskel catalogue appear very similar to those of the Hydr-star pump. In fact we can identify a part number in the Haskell catalogue (higlighted in yellow), which has the same displacement and pressure ratings for all three gases specified. This has to be more than a coincidence.
Haskel part number AG-152 has the same displacement and pressure specification as Hydr-star AGB06–2S-150. Notably, both part numbers begin with AG despite being different manufacturers.
Further we find the technical drawing for the two pumps is almost identical (Compare drawing below with the drawing in the Hydr-Star specifications image above):
The biggest difference appears to be 13mm more in overall length of the Hydr-Star pump. All other dimensions look identical, though there seems (Strategically?) a lack of ability to directly compare, the only dimension taken from the same aspect is the overall length. All the others are impossible to relate directly. This could be because they are exactly the same (Revealing the Hydr-Pump to be a more or less exact copy of the Haskel design).
Who knows what kinds of commercial dealings or non-dealings might be going on, or have gone on between Haskel and Hydr-Star historically, for Hydr-star to be offering what looks like an almost identical pump independently. We can probably guess Haskel will have had pumps manufactured in China, just like nearly all manufacturers have done.
We can’t concern ourselves with the moral questions of copying! Personally I have no problem with it. Patenting and Copyrighting is something I’ve grown more and more skeptical of, since I dabbled in it, having a historical registered patent for an electrical energy handling device myself, but that is just a personal opinion. It gives me pleasure now to know that the device I created was adopted for supply by a major international components manufacturer — even though I’ve never seen a cent or penny of revenue from the sales of it.
Interestingly the device I patented is an electrical analogy of what this pump is. The whole purpose of the pump is to translate low air pressure, high flowrate in the primary (air) circuit, to high pressure, low flowrate in the secondary (H2) circuit.
The pump is the gas equivalent of an electrical transformer.
So I am completely “At home” with it.
What should matter most to us right now is that this pump is on the table, on sale via Alibaba. It is possible we could invest the time and effort to go through the process of trying to acquire the authentic Haskel version of the pump, at most likely much greater expense, but Haskel is not showing it available “Off the shelf”, whereas Alibaba is.
Anyhow, knowing these pumps are more or less physically identical, we can use the Haskel specifications which are far more comprehensive than the specs for the Hydr-Star pump.
We find a handy summary with flow rate at psi for the Haskel equivalent pump on page 15 of the catalogue. I’ve highlighted the line detailing our pump of interest in yellow:
To compare the flowrate specified above with the flowrates we had for the Terek pump, we need to convert above to metric:
3.02 SCFM = 3.02*28.316 NL/min = 85.5 NL/min
This looks like more than twice the Terek pump’s stated 40NL/min capacity.
So it should easily do the job.
Further, Hydr-star offers racked pumping systems which are described as containing “Haskell similar” pumps. This gives us some peace of mind that if we do later find we need to have the pump racked in an assembly, Hydr-Star is capable of doing that too:
A suitable compressed air pump, which looks like it will easily do the job of supplying the compressed air needed to drive the hydrogen compressor is this one, again from Alibaba:
We need the smallest version of this, 0.8MPa 1.5KW, model number RMC1.5–8B, detailed in the product parameters section on the above web page.
It has a specified flowrate of 180L per minute, and has an integrated 40L tank.
It requires 380V supply which is compatible with an output from our 10KW fuel cell generator detailed in part 2.
Again the duty cycle of this air compressor, driving the hydrogen pump, will be most useful in computing its effect on system throughput efficiency, as used in our application.
Looking at the various options available, it looks like one or more “type IV” hydrogen storage tanks is the best option for our purposes of a large domestic or small community installation.
These are designed primarily for use in vehicle applications, but because they appear to have had most development effort, warranting and conforming to “type approval” standards, and are in most ubiquitous supply, they most likely also already enjoy economy of scale. The environmental and safety standards applying to them easily cover also the requirements of a residential or fixed building application. So they look like the most obvious choice.
There are racks designed to accommodate multiples of type IV tanks/ bottles, and the way pressure works, it is relatively is easy to scale / expand storage capacity by just adding more bottles with connnecting pipework, if we find a need to do that later, after the economic switch to Kardashev 1.0+ happens.
The tank selected from Alibaba, two of which are shown bussed together with hydrogen piping, is below:
Although the tank on that web page is described as 35Mpa (350 bar), probably because those are in most immediate stock, the same company, Wuxi Daze, offers a 70 Mpa (700 bar) version of it, which probably sells a lot more than the 35 Mpa version advertised.
The specifications for the range of bottles offered by Wuxi Daze is below:
The only 700 bar model there is DAZE410–65–70T
It has a capacity of 65 litres, take it or leave it.
At first this sounds like not much, given Enapter, our electrolyser manufacturer talking in their example about a vehicle hydrogen fuel tank of 500L.
However, using a suitable online calculator we can quickly check how much energy the tank full represents
The Stargate Hydrogen gas density calculator looks reliable, because it cross-checks with the answers from the DMN model I created to do these calculations per the NIST “Revised Standardized Equation for Hydrogen Gas Densities for Fuel Consumption Applications”
Here I advise caution, because unless we have to hand a reliable means of making these calculations, it is more or less impossible to tell when we are getting the truth from an online calculator, and I can say from experience most of them claiming to give hydrogen mass for a given volume and pressure, give seriously wrong answers.
The correct answer for a 65L bottle holding hydrogen at 700 bar, at 25C, is 2.55 kg.
Any calculator that gives a seriously different answer from this is a serious liar, and there should be laws against lying about this, imho. It is actually existentially important we know the truth, in general, but on hydrogen it is uber important, due to it also being something safety critical to work with.
The first online calc I tried gave an answer of 0.04 Kg.
If I accepted that answer I would have stopped the design right there, because that amount of hydrogen is next to nothing. It implies we could not conceivably bottle enough hydrogen to back up the energy requirements of a single household, never mind powering a vehicle for many miles.
So beware of those online liars, they are probably on the payroll of the fossil fuel mob, as always.
I won’t even supply links to them here, as that only helps them.
Gripe over, just pls beware of them.
2.55Kg is 2.55*33KWhrs of energy.
Recall 33KW is the output every 24 hrs from the Electrolyser, and this is the budget we have assigned to our example household.
So a single bottle is 2.5 days worth of energy storage for the household.
I would be inclined to add at least one more bottle to our rack, to ensure we really do have enough stored for any eventuality.
Then I’d add another two, to give us the capability to occasionally offer some hydrogen to others who might need it, or even to sell to passing hydrogen powered transport ^^.
If we had the financial budget to do this, as I am 100% certain we will have very soon, due to the required change of economy to Kardashev 1.0+, which nature will force, sooner or later, this would be a no-brainer, to max out the amount hydrogen we could store, because the more we could store, the more we could sell, and actually the more good we would be doing for the planet, because every kg stored is 33 kWhrs less energy that can go to heating the planet, at least until we sell the hydrogen, and then it is consumed.
As is, lets stick with two 65L bottles for now. We can always add more later.
Now we need a regulator to put on the bottles complement, to regulate the flow from the tank comprising bottles, to the feed of our fuel cell based generator, detailed in part 2. This is the last part we need to include in the end-to-end system DMN model, to ensure we include all the losses in the system efficiency calculation.
The regulator selected, again from Alibaba is the one below
https://www.alibaba.com/product-detail/70-Mpa-Hydrogen-Pressure-Regulator_.html
I am not sure why the above link does not activate to a followable link, whilst all the others in this article did. Hey-ho you will need to copy and paste to open it in a browser view.
Anyhow, this completes part 3, now we have all the parts needed, and the specifications from those, to plug into the DMN design model, except for the panels and battery backed power conditioner for those.
That will be covered in part 4, with part 5 concluding the series with the presentation of the updated DMN model, in all the detail needed for anyone to replicate.
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Further Information General References
Update History:
12/11/ — Air Compressor Product Parameters Added, reference to Hefei Sinopower manucturer changed to Wuxi Daze manufacturer.
My guest, Val Miftakhov of ZeroAvia, argues that hydrogen fuel cells paired with electric motors are the key to decarbonizing aviation. We discuss why he prefers his solution to sustainable aviation fuels or batteries, the challenges and misconceptions around supplying and refueling with hydrogen, and the tech roadmap from today's small retrofits to tomorrow's large jets.
(PDF transcript)
(Active transcript)
David Roberts
Okay, hello, everyone. This is Volts for April 23, , "What's up with hydrogen electric aviation?" I'm your host, David Roberts.
Aviation is one of the few remaining sectors that can fairly be characterized as "hard to decarbonize." At the very least, we're not entirely sure how we're going to do it yet, or if we can do it at all (which is one reason some people say the only solution is to fly less).
Lots of people, inside and outside the industry, are betting on sustainable aviation fuels (SAF) made with some mix of electrolyzed hydrogen and captured carbon, though such fuels remain extremely expensive and comparatively rare.
But some people — my people, the Volts tribe — are betting on electricity. For instance, in June of last year, I spoke with Kyle Clark of BETA Technologies about his battery-electric planes and electric vertical takeoff and landing aircraft (EVTOLs).
Today's guest, Val Miftakhov, has a slightly different approach. His company, ZeroAvia, makes engines rather than planes. Except, they're not engines exactly, because there's no combustion. Instead, the powertrain consists of hydrogen fuel cells that generate electricity and electric motors that use it for propulsion.
For now, ZeroAvia is swapping out engines in existing planes. Soon, it hopes to see new planes designed around electric aviation. And beyond that, it envisions redesigning the US flight system around more smaller airports, shorter hops, and ubiquitous hydrogen refueling. I am excited to talk with Miftakhov about all of that.
With no further ado, Val Miftakhov, welcome to Volts. Thank you so much for coming.
Val Miftakhov
Thank you for having me. Great to be here.
David Roberts
So, as I understand it, the "engine" — I'm using, for the purposes of this pod, all uses of the term engine should be heard in air quotes — so your engine consists of three parts, basically: you've got hydrogen storage of some kind, you've got hydrogen fuel cells that use the hydrogen to create electricity, and then you've got electric motors. So let's start with the fuel cell, because, you know, as I was thinking about this, I suspect most people, even a lot of energy-inclined people, don't really have a great sense of what fuel cells are.
So could you just explain quickly how a fuel cell creates electricity?
Val Miftakhov
Absolutely. And by the way, the confusion goes both from the general public, but also from the aviation folks sometimes as well, because in the standard aviation terminology, a fuel cell is where you put fuel in the aircraft. So we've got a lot of those as well. But overall, a fuel cell is an electrochemical device that takes some chemical, energetic chemical, like hydrogen, but there are other types of fuel cells out there, and oxygen typically from the air and converts that in an electrochemical device into electricity. Point of note, there is that there is no, as you said, combustion or there are no moving parts associated with it.
So, it's really looking more like a battery with a number of cells arranged in a stack, and then you get a fuel cell stack that produces a large amount of electricity at relatively high voltage. So, similar to a battery pack. But of course, you know, with the fuel cells and especially with hydrogen fuel cells at the system level, you get much, much higher energy density or specific energy in terms of the amount of energy per unit of weight of the system.
David Roberts
Well, I want to return to that in a second. So, just on a kind of first principles basis, why fuel cells instead of SAF? Why fuel cells instead of combusting synthetic fuels? What's the advantage?
Val Miftakhov
Yeah, very good question. And the advantage comes from two sides. One is on the impact of why we're doing this altogether. Why do we care about moving to sustainable fuels or moving to new aviation? We're talking about a couple of things there. One is pollution, of course, which has multiple elements, so carbon is one. But there is also non-carbon effects on climate and on health. There are a lot of studies that put, without any doubt, adverse health effects around the airports because of the particulate emissions, because of the high NOx output, nitrogen oxides from the combustion from those engines.
And, in order to get away from all of that, you really need to get away from combustion. So, as long as you're burning fuel, you're still having all of those negative effects. So, you can burn zero carbon fuel, you still have those effects.
David Roberts
You still have the particulates and the NOx and other kinds of air pollution.
Val Miftakhov
That's right. And you know, there are other negative self-combustion of course, because you have high temperatures and pressures, your materials are stressed and as a result, your maintenance costs are higher. But those are sort of softer effects. The hard reason, at least for us at ZeroAvia and similar pioneers out there and people who support us like Breakthrough Energy Ventures, you know, Amazon Climate Pledge funds, people who really try to force the transition of hard to abate sectors, these combustion effects are really, really important. So that's one aspect of things. The second aspect is that sustainable aviation fuels that are based on synthetic hydrogen production and carbon capture, as you mentioned in the beginning, those are fundamentally much more expensive than hydrogen fuel cell propulsion because you can use with hydrogen fuel cells, you can already use that green hydrogen that you produced without going through carbon capture without going through the chemical plants architecture that combines that hydrogen with carbon and produces liquid fuels.
You can use hydrogen directly in the fuel cell system, and you can use it more efficiently because the fuel cells, the current generation of fuel cells, already are 60% or so efficient. And the best combustion engine we have for aircraft, the largest engines that we have, are about 50% efficient. But the vast majority of the engines on the smaller aircraft, under 100 seats, are less than 30% efficient. So, you have double the efficiency. You don't need any of the carbon capture or any of the chemical process beyond it. So, economics becomes much, much better. So, these two factors, we think, undoubtedly, to us at least, point to hydrogen fuel cells as the eventual solution to this problem.
David Roberts
So, A) you're getting more energy out of the clean hydrogen you produce just because you're not sending it through elaborate chemical reactions and creating some new fuel out of it, you're just using it directly. And B) no pollution. And as far as we know, this is the only genuinely no pollution flight option that we have. Right. I mean, any combustion basically entails some of these particulates and NOx, etc., right?
Val Miftakhov
Yeah, that's right. And you know, hydrogen combustion is obviously cleaner than hydrocarbon combustion because you don't have carbon in the chain, so you might not have particulates. But hydrogen burns hotter. So anything that burns hotter produces more NOx. So there are disadvantages there. Electrification is really the only, what you call, true zero-emission option. Yeah. Now we've done the end-to-end sort of life cycle analysis as well. And there is, of course, you need to produce engines. So there is some emission in that potentially. So the total abatement is anywhere sort of around 95%.
David Roberts
Wow.
Val Miftakhov
Of the climate effects.
David Roberts
And all that remaining CO2 is in the embedded CO2 of the manufacturing process. There's no direct CO2 at all in the flight or the operation?
Val Miftakhov
Yeah, and theoretically, this is, you know, calculated using the current sort of energy intensity and energy composition of the manufacturing processes. If we eventually move to 100% renewable energy-based manufacturing and extraction of some of the minerals that are required for building the fuel cells, maybe we could get to 100% abatement. And that's the beauty of these technologies. Kind of similar to the electric cars. Our grid is not obviously 100% renewable right now, but it's getting more and more so. So, you put an installed base of these engines, of these motors out there, those cars, and it gets cleaner and cleaner and cleaner over time.
David Roberts
The second, fundamental engineering question is, then, why fuel cells instead of batteries? You sort of mentioned it just has a higher specific energy. But in specific energy, as I understand it, is just the amount of power you can get per weight. Is that right?
Val Miftakhov
Yeah, energy per weight. And maybe some history for myself. Before I started Zero, I was running a company called eMotorWerks, before ZeroAvia, for about seven years. And what we built there is the world's largest network of smart EV charging stations. So, I was involved with the electric car industry quite a bit. I had, in addition to the large network of charging stations, relationships with 10+ automakers controlling charging of the vehicle's energy flows, directly controlling the batteries and battery management systems in the cars. The point I'm making is that, you know, through that work, I got pretty exposed or our team got pretty exposed to all the challenges of the battery technologies and how quickly it can evolve.
And when I started at ZeroAvia, I think there were 60 projects out there of various novel aircraft ideas that are all based on batteries. And people were telling me that, "Hey, well you know, this hydrogen thing doesn't make sense because in five years we're all going to be flying on batteries hundreds of miles because they're going to become five times, ten times better."
David Roberts
Right? Everybody's betting on batteries continuing to go down this curve, right? Cheaper, cheaper, cheaper, more and more energy density.
Val Miftakhov
Yeah, and cheaper, cheaper, cheaper, I agree with. Right, because that's an easier thing to get, right? You go higher volume, you increase extraction, you optimize processes, you put robots everywhere. The cost can decrease quite dramatically. But the energy density, or specific energy to be precise in the terminology per unit of weight, is very hard to move. This is an electrochemical problem and there are a lot of trade-offs. There are theoretical limits. So in the beginning, when I started Zero, we did some modeling of what would an absolutely ideal battery do if there was such a thing?
Right? And the way you do it, or the way we did it, is we said, "Okay, what is a battery?" The battery is something that has an anode, a cathode, and there are charged ions moving between them. At least that's how we understand the battery for the last, you know, 100+ years. Okay, and what can be the lightest carrier of that charge? You need a metallic ion. The lightest metal is lithium. So that's the absolute lightest possible ion carrier. If you just take the mass of the lithium atom and calculate the energy, maximum specific energy, just based on that, you end up somewhere around just over 10,000 watt-hours per kilogram.
So, no battery can theoretically ever be close to that number. Okay. And that's before you think about anodes, cathodes, all the electrolyte, all the material around it.
David Roberts
It's just the weight of the lithium itself.
Val Miftakhov
Exactly, exactly. And you have to divide it at least by a factor of three to five, because you have an anode that has to, you know, accept all those ions. And a cathode, the same thing. Right. Because these things do move around and they need to be mechanically stored somewhere. So all those things. And then you look at hydrogen, for example, it starts. Chemical energy of hydrogen per kilogram basis is 33,000 watt-hours per kilo. Okay. So you already start at 3x relative to the maximum possible theoretical, which is actually not achievable. And then you say, "Okay, well, clearly these things will never meet, because they can't."
So, hydrogen going into fuel cells will always be better. And then you look at the current state. Even back in the day, I was looking at the hydrogen versus the then state of the battery. You look at the current state, and we're still — depending which generation of battery you use — you're anywhere between 30 and 50x delta on the specific energy output. And yes, batteries improve single digits per year in the specific energy. But 30 to 50x is a big gap to close, and we know that it cannot be closed fully because of the theoretical limitations.
David Roberts
Okay, so this is why hydrogen instead of batteries. A quick question just about form factor. So you're swapping, you're taking sort of existing small planes, as I understand it, you're starting small and just taking out the old engine and putting one of these in. So I'm a little curious about the form factor. Like, do you cram these parts together into something that is roughly the shape of an engine? Like, does it look like — if I was looking at it, would it look like an engine to me?
Val Miftakhov
Yes and no. Some parts would, especially the ones that connect to the propulsors. Propellers, for example, in small planes. So, we need to rotate those propellers. They're located in a certain place, either in the cells or the front of the aircraft. So, you know, the motors. The motors will look similar and they will be in a similar place. The rest of the system, we have the flexibility to place it elsewhere. And we do.
David Roberts
The fuel cells and the hydrogen storage are somewhere else in the plane?
Val Miftakhov
That's right. They could be. Typically, in the existing aircraft, it's hard to find a place for the fuel cells in the same place where there is an engine today, partially because, you know, fuel cells still take a little bit more space, but also for some of the vehicle weight optimizations, we're still heavier than the turbine engines. So, center of gravity issues, you know, weight and balance on the aircraft need to be taken into account. So, for the existing aircraft, we tend to have to separate the fuel cell system from the propulsion system.
David Roberts
So what is the current plane like, what do you have that can run a current plane and then sort of like, what's next? When we're talking about sizes and classes of planes, just talk about, like, what you can do now, what's next? And like, what's the target?
Val Miftakhov
Of course. So, the exciting part — I start from the end of your question — the exciting part of this technology and this approach is that it can, over time, be applied to any size of the aircraft that we have today.
David Roberts
I read the white paper, and I want to talk about some of those innovations that would be necessary here in a minute. But let's just talk about what we can do now.
Val Miftakhov
Yeah, so that's the exciting bit and that's what excites me, our team, our investors. Right. Because we don't want to be working on something that can only affect these small aircraft because that's a relatively small portion of the market. That said, we are very pragmatic. We start with the first application in the smallest aircraft that is commercially meaningful from the market perspective, market size perspective. And that tends to be aircraft 10 to 20 seats in size that's powered, generally speaking, by engines at around horsepower. Okay. And 10-seat aircraft tend to have one of those engines.
20-seat aircraft would have two of those engines on the wings. And that's our first product. So the first product is around 1,000 horsepower. We have flown a number of variants of it. It is now in final design, submitted for certification about 15 months ago. And we're in the middle of our certification work right now.
David Roberts
So, I can't quite yet bring my plane to you and have you swap it out. That's waiting on some final stamps of approval.
Val Miftakhov
Right. Well, you can, but you won't be able to fly it commercially. So, we of course have flown a number of these engines in different aircraft. They work. We know how they work. We have done the integration in several airframes, but in order to operate them commercially with passengers inside and paying cargo, we need to have the stamp. Yeah. So, we are working on getting that.
David Roberts
And so, for listeners' benefit, like a 10 to 20 seater plane, A) how big of a chunk of aviation is that? And B) what do those planes do? What are they used for?
Val Miftakhov
Yeah, so in terms of the size of the market, by dollar amount, this is probably less than 1%. By total number of aircraft in commercial service, this is between 5 and 7% of the total. Because there are fewer seats, you have more planes, but the revenue is lower on a per plane basis. So today, these do, for example, cargo, package delivery in less dense locations, or passenger transport at smaller airports. So, for example, some of the vibrant use cases for that include island networks. Like, one of the largest fleets of 20 seat aircraft, for example, is deployed in the Maldives.
David Roberts
Oh, interesting.
Val Miftakhov
Yeah, over 100 aircraft are flying there and nothing else can really fly there, at least to the smaller islands because there are no runways to take jets.
David Roberts
Yeah, I think we have some, if I'm not crazy. I'm pretty sure we have some of those in Seattle just doing short flights like up to Victoria B.C. and things like that.
Val Miftakhov
That's right. Absolutely right. And you know, in general, especially in B.C., the coastline beyond Vancouver is pretty rough to go around. So, there is a lot of aircraft, small aircraft activity going on. And you can go even more extreme, and if you've been to Alaska, for example. Right. Everybody's flying because the roads are not as easy to traverse. Hawaii is a big area as well for these types of planes, again for the same reason.
David Roberts
Yeah, so there's a market, in other words, for you to get running. Get running on. So then, what's the next class up?
Val Miftakhov
So, the next class is larger propeller planes. These are some examples. Two manufacturers really, mostly ATR, which is a 50% joint venture between Airbus, who everybody knows, and Leonardo, an Italian manufacturer, probably not as many people know, but ATR is the largest manufacturer of these large propeller planes. They have a 40 seat variety and 70.
David Roberts
40 to 70.
Val Miftakhov
Yeah, 40, 70. And then there is a De Havilland Canada Aircraft Corporation that makes today up to 80, I think up to 80 seat aircraft called Dash 8. And those aircraft are our next target. And that's the engine that generally produces about 3,000 to 5,000 horsepower. And we have demonstrated already ground operations of components of that engine on the systems that we took from one of these 80 seat planes. And that is a project together with De Havilland Canada and Alaska Airlines, who's one of our investors and partners as well. So, for the small engine, 10 to 20 seat, we finalized the design.
It's now in certification. We're hoping to put it in service in commercial service next year, . The larger engine is now in development, prototyping. We go through iterations and if everything goes right, we'll submit it for certification in the next two years.
David Roberts
And that'll be the 40 to 80 seaters. And what are those used for? Are those passenger planes mostly or the larger cargo?
Val Miftakhov
A little bit of both. We have some exciting discussions actually with some of the cargo carriers to help them expand their cargo networks with these smaller planes. For them, it's smaller planes because they fly jets today, but they want to improve the fast delivery of goods and packages to smaller locations, smaller metro areas. And this is how you do it, again, because you know a lot of those locations cannot accept large jets. And similar on passenger. A lot of these aircraft are used today. So in terms of the markets, this next size propeller planes, in terms of the dollar amount, this is probably 3-5x the market of the small planes.
David Roberts
But still, both combined are relatively modest, compared to what I'm guessing is the next class up, which is the big ones. Right. Is there a middle class I'm missing?
Val Miftakhov
There is a middle class today, regional jets. So, those are the two manufacturers. There are Mitsubishi Heavy Industries regional jet, formerly Bombardier. So, this is the class or brand of the aircraft called the CRJ regional jets. There are about of those in operation worldwide. And then, Embraer is probably more familiar and they have well over a thousand as well. So, these are regional jets. These are generally under 100 seats in size. They fly faster than propeller planes and that's why operators like them. And that's the next segment. So, we started some work with some of those manufacturers already, but no hardware yet, but that will be the next segment.
And the segment after that is the segment that has the majority of the dollars right now in the market, and that's called single-aisle aircraft or narrow-body aircraft. The examples, classic examples, are Boeing 737 and Airbus A320 or A321.
David Roberts
Right. These are the ones people will be familiar with having flown on.
Val Miftakhov
Yeah, yeah. Well, you know, I think most people who are flying will have flown as well on a regional jet on one of the Embraers from time to time. But most of the time today, if you're boarding a plane, you're probably boarding a single-aisle aircraft.
David Roberts
Right. And so, those two upper classes, some pretty big engineering advances are going to be necessary to get there, which I want to discuss in just a minute. But I got a couple of questions first. A couple of things about these existing engines. One is, you know, I know from the EV space that electric motors require much, much less maintenance than combustion motors. Just because you're not trying to control a bunch of explosions and toxic gases. There are fewer parts, fewer moving parts, fewer rotating parts, etc. Does that extend to hydrogen fuel cells as well? Like, is this package much lower maintenance than an equivalent combustion engine?
Val Miftakhov
Absolutely. It's exactly transferable, that logic. So, we use electric motors. So there, it's directly transferable. And the fuel cells also have no moving parts. There are some moving parts, most notably a compressor, an air compressor, because the fuel cell is an air-breathing machine. So, it needs to have high-pressure air delivered to it. So, you have to have a compressor, which is rotating, but the compressor itself is an electric motor connected to a turbine. So, it is also quite reliable. As a result, you have maybe a couple of moving parts in the system like a motor and a compressor, and then everything else is non-moving parts.
David Roberts
And also, not hot.
Val Miftakhov
True. Yeah, great point. Which has some strong additional advantages. For example, because you don't have combustion, you generally don't have noise as well.
David Roberts
Right.
Val Miftakhov
Combustion is very noisy.
David Roberts
Same for EVs. And transferable from EVs.
Val Miftakhov
Absolutely right. You have the same advantages as you would have from the battery electric drivetrains, but you have more energy that you can carry with you. And by the way, I think the right tool for the right job and I think electric propulsion is perfect for cars for ground transportation, electric being battery-electric, for ground transportation, especially for smaller vehicles.
David Roberts
Right. So, you're not pushing hydrogen vehicles. A lot of people, a lot of people in my audience, love to hate hydrogen cars. It's purely an aviation thing for you, right? You think batteries can handle most of the other stuff.
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Val Miftakhov
Exactly. In fact, it was quite annoying to have to, you know, unpack or undo that damage that the car industry, some of the car industry, did to hydrogen in general. Because they, as I called, they started from the absolutely wrong side of the hydrogen story. They went into light consumer vehicles, which is the worst place to apply this to. Right. Like, why would you do hydrogen? Because it is more complex than battery electric, okay.
David Roberts
We'll also, and we're going to get to this later, but like green, genuinely green hydrogen is still pretty expensive. What is the analogy someone said about when they talk about using hydrogen to heat homes? He's like, "That's like pouring champagne into your municipal water supply," you know what I mean?
Val Miftakhov
I like it.
David Roberts
Green hydrogen is rare and expensive still, so you want to use it wisely.
Val Miftakhov
Exactly, exactly. So, if you ask yourself, "Okay, I have a battery as an energy source and I have hydrogen fuel cells as an energy source, how do I think about the relative application of the two?" The way you would do it is you would say, "Okay, which types of, in this case transportation, require higher specific energy, like more energy on board the vehicle?"
David Roberts
Right.
Val Miftakhov
And you look at, you know, let's say cars, for example, personal cars, and you can approximate this variable by, in the standard fuel vehicles, what percent of the vehicle mass or weight you have in fuel, like fully loaded, fully fueled, you know, what is that percentage? If you look at personal vehicles, small cars, that's 2 to 3% of the vehicle mass goes into gasoline. Okay. If you look at a 737 Max, up to 40% of the vehicle can go into fuel. So this is a 20x difference already on that dimension. And then you say, "Okay, what else?"
Right. One other dimension you can use is, you say, "Okay, what percent of overall, let's say 24 hours in a day, that vehicle is moving or using that fuel." And again, personal car, 95% of the time it sits somewhere and it's not moving. A typical commercial aircraft, especially regional aircraft, they're used more than 50% of that 24-hour period. Then you say, "Okay, well the higher the energy utilization and the higher the vehicle utilization, the more hydrogen is applicable versus battery." Because you know, you need a lot more energy.
David Roberts
You just need more energy on board.
Val Miftakhov
That's right. You need more energy on board and you cycle through that energy quicker. Which means, you may need even more energy on board per unit of time per day, for example, and you need to recharge or refuel much faster. And you look at different types of transportation and you will clearly see that the consumer vehicle is absolutely the worst for hydrogen versus battery and the commercial aircraft is absolutely the best. Yeah, so that's why we were like, "Hey, the whole market started from the wrong place. And as a result, it got all this bad rep, because it's just not something that you should start with."
Eventually, maybe we'll get to that point when we have all the airports with hydrogen, all the heavy-duty long-distance trucks, maybe fueling in the same locations and the, you know, hydrogen network gets developed, everything is done and then maybe you can plug in also these types of uses like small cars, but not from the beginning.
David Roberts
Right. So, on the maintenance thing, give us a comparison. For example, if I have a combustion engine in my 20 to 40 seat plane, how long is that engine going to last versus how long one of these systems would last?
Val Miftakhov
Yeah, so I'll give you a comparison for the first segment, which we have studied quite a bit. And we already, you know, we are now in certification, so we haven't deployed any of these in commercial service, but we sold about 3,000 engines already to the operators pre-sold.
David Roberts
Oh, so people are ready to go with these once it gets the final approval.
Val Miftakhov
That's right. That's right. Because. And the biggest reason for this pipeline, if you will, of orders is because we can drive better economics. And most of the economical advantage comes from maintenance. Maintenance is a big, big source of operating costs for these operators. Part of this cost is direct, right? So you need to maintain, you need to replace parts and all that. But the big part of the cost is downtime, service downtime that you have to take — if there's anything wrong with the engine, you need to repair the engine. But also the airplane sits on the ground not doing revenue work and the operator loses money.
So, maintenance is a large part of the operating cost implication there. And we're able to reduce that maintenance cost and downtime by 2-3x for the operator. And that's a huge advantage. And that's one of the primary reasons why operators are putting these orders in. Because we're able to communicate and show, frankly, you know, based on already our engine operating records and the fuel cell and the electric motors operating records that will be much, much better. To give you some examples, on the 10 to 20 seat aircraft, the engines that are operating today, small turbine engines, have major maintenance intervals at around hours and complete engine overhaul, which means that, you know, you basically have to rebuild the engine or replace the engine at hours of operation.
David Roberts
Oh, that doesn't seem like that much.
Val Miftakhov
It's not a lot. It's not a lot for a regional aircraft that is in reasonably frequent operation. That's about a replacement of the engine every three years.
David Roberts
Oh, my gosh.
Val Miftakhov
Okay, so a typical aircraft, commercial aircraft, airframe itself lasts for 30 years. You know, that's kind of the average. So imagine you go through 10 sets of engines. You can go through 10 sets of engines on that aircraft. So, maintaining the engines is a big, big deal for the operators. With the fuel cell system, fuel cell electric, we can go up to 10,000 hours between the major overhauls, and major overhauls are not as dramatic because the electric motors will last for the duration of the airframe for 30,000 hours. And I'm sure Kyle told you all that already.
So, then we're back to sort of the automotive analogy where you don't expect to change the engine on your car, right?
David Roberts
So is it the, like when they do need maintenance or when they do break down, is it the fuel cells that are usually the source?
Val Miftakhov
Yeah, and it's not a breakdown, it's more of the degradation of the fuel cell. And we'll see what happens with batteries really in aircraft as well, because in cars, I think by now, especially Tesla has shown that the batteries can last the duration of the lifetime of a car as well. But in aircraft, they're utilized much more thoroughly, if you will. So we'll see how that goes. But you know, for fuel cells, this is degradation, gradual degradation of the fuel cells. And then at some point, you cannot produce maximum power anymore and there is a certain margin that you certify with and you eat into that margin.
And at 10,000 hours, you say, "Okay, well now you need to replace the stack."
David Roberts
I'm curious how sort of modular all this is. Like, can you pull an individual fuel cell out and replace it or what? How chunky is this?
Val Miftakhov
Yeah, very good question. So, it is modular. Giving you an example, for our 600 kilowatt engine or this horsepower engine for 10 to 20 seat aircraft, it has eight stacks in it arranged into four pairs. So, a pair is a module. So, we can replace on a module by module basis. And those are even the design of the integration of those modules into aircraft is done with maintenance in mind so that you don't have to, you know, take apart the whole thing in order to pull this out. Right. You can just unbolt a few things, undo a couple of connections, and you can swap it in the field, you know, so you don't need to have a huge downtime on the aircraft.
The strong benefits, additional benefit is that because you can make this system so modular, it's much more reliable because you have automatic redundancy. Right. Versus a typical single-engine aircraft, if something goes wrong with the engine, well, you now have a glider.
David Roberts
So, failure modes. Better failure modes than combustion engines. Interesting. I want to talk about, I mean, one of the most interesting aspects of all this. So, you know, as we've said, you've got the 10 to 20 seater engine almost ready to go. Almost in commercial use, probably later this year, maybe?
Val Miftakhov
No, next year, '26.
David Roberts
Next year. And then you get the 40 to 80 seater next. But then, as you say in this white paper that your company has put out, going to that next class, up to the regional jets and higher, is going to require some big engineering advances. And so there are three basic components here. There's the hydrogen storage, there's the hydrogen fuel cell, and there's the electric motor. All of whom are going to need to advance in fundamental ways. And there's a line of sight to pushing them forward. Very, very interesting. So let's start with the hydrogen. So right now, hydrogen has good, what they call gravimetric density. It's very light for the amount of power you get out of it. That's a real advantage in flight. But it has very poor volumetric density, which means it's very diffuse. So it's like it takes up a lot of space if it's a gas.
And that's what you're using now, gaseous hydrogen. So it says in the paper, if we want to get enough hydrogen on board and have a manageable space for it to occupy a manageable amount of space, you have to go to compressed liquid hydrogen. Is that accurate? Like, what is the leap there from gaseous to liquid? What's involved in that?
Val Miftakhov
Yes, you have to go to liquid hydrogen. You're exactly right. And the challenges with that — well, it is kind of rocket science. I was going to say it's not rocket science, but it is kind of rocket science. Because the largest use case right now for liquid hydrogen is in rocketry, rocket engines. But there is also significant use in the industry. In fact, even in ground-based vehicles. Most of the deliveries today from the production sites to the fueling stations on the ground are with liquid hydrogen because of the volume on the roads.
David Roberts
Just a quick question. If you get liquid hydrogen, do you then have volumetric density in the neighborhood of jet fuel? How close can you get to matching the volumetric density of jet fuel?
Val Miftakhov
Yeah, very good question. Not quite. You're still on the chemical energy basis, you're still about three, three and a half times more volume for liquid hydrogen.
David Roberts
Got it.
Val Miftakhov
Now, when you sort of account for the difference in the efficiency of the engines. Yeah. Because back to the beginning of our conversation, combustion efficiency is much lower than the fuel cells. So when you account for efficiency difference, you're about 2x more volume.
David Roberts
Ah, so that gets you a little of your volume back.
Val Miftakhov
That's right. But you're still twice as much. So, the other way to say it is, you can get half the range with the same volume.
David Roberts
Got it.
Val Miftakhov
Okay. And in order to kind of move away from that restriction, that's when you start talking about new types of aircraft design that have more volume for hydrogen. Good examples of that are, you know, I don't know if you're familiar with a company called JetZero down in Los Angeles, for example. They are designing and building a blended wing or wing body aircraft, large size, 200 seaters or similar cargo capacity that has those blended wing designs. They have a lot more volume just by the nature of it.
David Roberts
And even if you make it liquid, is it still pretty light? Like, is it still mostly a volume question and not a weight question?
Val Miftakhov
Yes, absolutely.
David Roberts
And one other question about liquid hydrogen. If you have a canister of highly compressed liquid hydrogen, don't you effectively have a bomb? I think what comes to a lot of people's minds when they think about this. Aren't you effectively flying on top of a couple of extremely potent bombs?
Val Miftakhov
So, definitely a frequently asked question on hydrogen. Actually, in fact, for the first year of ZeroAvia, my second slide in my presentations was Hindenburg. Because everybody would ask that question anyway. So, like, I better get it out of the way right in the beginning.
David Roberts
Well, gaseous, not so much, but liquid hydrogen, then you really are. That is a lot of energy crammed into a small space.
Val Miftakhov
Well, the amount of energy, the absolute amount of energy, is about the same, or half of the amount of energy that you have in the jet fuel in the same volume. Right. So, about the same if you want the same range, but about half if you put it in the same volume.
David Roberts
Right.
Val Miftakhov
So, from the total amount of energy, it's not that different. It's a matter of, you know, how you manage this chemical energy, how do you ensure safety?
David Roberts
You could just reply: "Existing planes, big fuel tanks, are bombs."
Val Miftakhov
Those are flying bombs.
David Roberts
Those are bombs, too.
Val Miftakhov
Exactly. So they carry the same amount of energy or more. And in the right conditions, that energy can be very quickly released, as you've, I'm sure, seen in some accidents. And for hydrogen, actually, there are a lot of safety factors that favor hydrogen, and NASA has done some work on it and some other people have done some work on it. To give a couple of examples, for instance, you know, a lot of accidents in a traditional aircraft, the sequence looks like this: pilots are able to get the aircraft on the ground, it's a hard landing or it overruns the runway, fuel tanks get ruptured, you have a fuel leak, it ignites, and, you know, there are tragic consequences.
With hydrogen, you cannot have a leak that pools on the ground. If you have a leak, if you have a tank compromise, let's say a crack in the tank, for instance, you have a leak that immediately dissipates up in the air.
David Roberts
Right. But we should say, spewing hydrogen directly into the air is a pollutant that is bad.
Val Miftakhov
That's right. Obviously, an emergency situation. You don't want to do it. But it doesn't kill everybody. So, you know, obviously nobody wants that to happen. And it will not happen with any kind of frequency. But if it happens, then the properties of the release of fuel are such that it's much less dangerous. And it has actually been shown, there are some interesting videos from, I think, the Department of Energy actually, tests of hydrogen car fires versus gasoline car fires and with temperature sensors in the cabin and all those things, and, you know, how things are affected.
And it's a pretty dramatic difference, in favor of hydrogen, in that case.
David Roberts
It is kind of funny how paranoid people are about it, given the fact that we're all always riding around with giant tanks of flammable fuels in close proximity.
Val Miftakhov
But this is how people are, right? So, remember when Tesla was putting its first cars out there? Every Tesla fire was like worldwide news.
David Roberts
I mean, still, really still, it is kind of a little bit like that.
Val Miftakhov
But it is super rare. It is super rare, relatively speaking. And on hydrogen, last thing, we have right now maybe around 100,000 hydrogen vehicles, ground vehicles, between cars, trucks, buses, forklifts, all that. And you don't hear about hydrogen vehicle fires, and you would hear about hydrogen vehicles if they were happening. Okay. And you don't, because they don't happen.
David Roberts
All right, so let's talk about then, innovation in fuel cells. So, fuel cells, the category fuel cells, is very broad. It can do a lot of different fuels, can go in a lot of different designs. I'm assuming for this very specific application, you're designing your own fuel cells and innovating on your own fuel cells. So, what is the sort of path for innovation on the fuel cell side? How do you get more out of that?
Val Miftakhov
Yeah, correct. So, specific designs, especially for larger aircraft, and larger is already, you know, these large propeller planes already require significant modifications and new designs. And then when you get to jets, it gets even harder. So, the direction of research there, research and design, is moving to higher temperature fuel cells, which require material change. So, it's not just, "Hey, let's crank up the temperature." You have to move from some of the materials that we are using today in fuel cells to new materials. And we have that design and development in house.
David Roberts
Is it just that the chemical reaction is more efficient in higher heats?
Val Miftakhov
Yeah, it is a little bit more efficient. Yes, you increase the temperature, generally, you know, chemistry likes temperature increase. Things happen faster, more efficiently in smaller volumes. And importantly, here is it's much easier to cool higher temperature systems than lower temperature systems. So let's say you have, you know, 50% or 60% efficient fuel cell. This means that 40% of the chemical energy that you feed from hydrogen transfers to heat. It is much better, much lower level of heat than in a combustion engine, but you still have a lot of heat, and you have to remove it. Now, if you are operating like traditional fuel cells in the cars, for example, and the type that we have in the first engines, if you're operating at about 90 degrees Celsius and you're sitting on the tarmac at Phoenix airport, for example, or even worse, Abu Dhabi, for instance, in the summer, your difference between the 90C temperature of the fuel cell and let's say 50C ambient temperature is quite small.
So, it's just a 40-degree difference that you have to move the heat out of your fuel cell. Now, if you increase the temperature of the fuel cell to about 200C, and this is our high-temperature fuel cells that we're developing in-house, then your Delta T or the difference in temperature goes from 40 degrees between 90 and 50 to 200 minus 40, minus 50 or 150 degrees, which is almost four times larger difference in temperature, your cooling becomes four times easier.
David Roberts
Okay, why is cooling easier when you get hotter waste heat?
Val Miftakhov
Yeah, because it's like when you boil water, right? If you have boiling water and you look at how quickly it cools from 100 degrees down, you will see that the first 10 degrees are much faster than the last 10 degrees. Because when it gets closer to ambient temperature, the heat flow rate slows down dramatically. And well, mathematically or physically, you never get to the ambient temperature because it's asymptotically slower and slower. So that hurts the lower temperature fuel cells. So, you need to increase the temperature.
David Roberts
And can you also increase efficiency and thereby just get less waste heat?
Val Miftakhov
Yeah, you get a little bit of increase in efficiency. And you get an increase in efficiency also from the system side. It's a little more esoteric, I guess, a nerdy discussion. But because you have now hotter exhaust, you can use that heat also. You can recover some of the energy from the exhaust heat as well through a turbine. So your compressor becomes sort of this compressor-turbine combination that it's almost like a turbocharger on your car.
David Roberts
You're using the waste heat to compress the air.
Val Miftakhov
That's right. That's right. You use part of that energy to add to your compressor. So, you need a smaller compressor drive and you save some energy there, and your system becomes more efficient as a result.
David Roberts
Do we have any sort of target efficiency, or would you say current ones are in the 60% efficient range? Is there a theoretical limit here, or is there a target efficiency?
Val Miftakhov
Yeah, the theoretical limit for a fuel cell is, I believe, around 94%. That's the theoretical limit. So it's quite high up there. Yeah. Now there are, you know, obviously several reasons why, you know, we're not at a theoretical level or nobody's at a theoretical level, but there are fuel cells out there that already operate in the 70s at relatively low power levels. So we are obviously cranking them up at quite high power levels. So there is some work to do. But it is a material challenge mostly in the conductivity of various coatings and membrane materials.
David Roberts
So, for the fuel cells, it's a materials science challenge mostly. Interesting. And you guys are doing all that in-house. Are you able to draft it all on a broader scientific push in fuel cells? Like, are a lot of other people working on fuel cells?
Val Miftakhov
Yeah, definitely there are. On the high-temperature side, there are probably three companies, including ourselves, on the top of the field. And then there are some sort of tier one partners that we're working with. Like BASF for example, is a big German chemical company and they're working on some membrane materials that we are utilizing. We have a joint venture or joint work development with them.
David Roberts
And do you lose any of the safety benefit when you introduce high heat back into the mix?
Val Miftakhov
Not really. Because high temperature is still, you know, very low temperature compared to combustion. Right. We're talking about 200 degrees versus almost 2,000 degrees of combustion temperature. So as a result, you know, we can use simpler materials still, like aluminum, for example, which is cheap, it's very formable, it's very heat conductive and electricity conductive versus, you know, turbine engines have to grow single crystal turbine discs out of Inconel.
David Roberts
So, the last piece here, so we got innovation in hydrogen, mainly compressing it into liquid is going to be necessary for the bigger planes. We got innovation on the fuel cell side, trying to increase the temperature of the fuel cell process, increase efficiency output there. And then the other piece is the electric motors and rotors. Now, this is the question I always have about electric motors. Like at this point in things, there just have to be like gazillions of people working on making electric motors better. I mean, these are everywhere. They're getting more and more ubiquitous.
They're doing more and more things. So, there just has to be like a ton of work happening here. Like, what is your piece of that? Are you personally trying to make electric motors better? Are you focusing on sort of the plane-specific parts of it like the rotor or the propeller, or what's the innovation on that side of things?
Val Miftakhov
Yeah, your intuition is absolutely right. This is, I would say, the least complicated part of the equation for us. We do have to design and build our own motors or aviation-specific motors. But that mostly is because the design process for aviation certification is different. And you kind of have to start from scratch to do it, but the principles are the same. If anything, at some point in the future, maybe when we get to the largest engines out there, let's say similar to what drives a 787, we're even beyond the single aisle. That's when people start talking about maybe cryogenically cooled electric motors with superconducting, you know, windings and things like that.
But really, it's not even required. If you think about the kind of challenges between the current state of technology and where you would need to go for these large aircraft, the biggest challenge is in the fuel cell. The second biggest challenge is in the fuel tanks, fuel storage, and fuel system. And the last, sort of the smallest challenge, is in the motors.
David Roberts
Interesting. Very interesting. All right, well, we're running out of time, but I have two big questions left. This is all just super fascinating to me. So let's talk a little bit about, right now, when I started reading about you, the company, when I found out that you're just swapping engines in existing planes, I thought, "That seems kind of crazy" because in, like the EV space, the reason EVs are working is that they're designing lighter bodies and stuff around these engines so you can just go farther. Like trying to take a big old heavy metal, you know, existing combustion car and lifting out the engine and putting in an electric engine is you're just setting a very high bar for the difficulty there.
So, it seems like you're doing difficult things trying to lift these heavy planes. And I just wonder, are people — I mean, I know people are out there designing new kinds of planes around electric propulsion systems, this is probably like a whole podcast in itself, I'm sure. But, like, what could you say briefly about just sort of like, what does that look like? And are you working with specific designers making specific planes around your specific propulsion system?
Val Miftakhov
Yeah, it's a very good question. And yes, we have some clean sheet projects as well. I think three or four at this point. A couple of them are public.
David Roberts
And these are like different, fundamentally different design ideas about it?
Val Miftakhov
Yeah, it's different, different materials, sometimes different materials. Mostly, you know, a lot of composite materials.
David Roberts
Carbon nanotubes or whatever.
Val Miftakhov
Yeah, mostly. There is a bit about structural integration of components. So, you can use, for example, the hydrogen, compressed hydrogen fuel tanks are likely the strongest components of any airframe you would integrate them into. Because these are basically, you know, almost 1cm thick carbon fiber shells to contain the high pressure.
David Roberts
So, you can make them like load-bearing. Oh, that's interesting.
Val Miftakhov
You should, you should. Right. Because again, this is the strongest part of your airplane. So, you can, for example, there are some concepts that say, "Well, why don't we build wing spars out of those things?" These are basically a structural element that keeps the wing in shape.
David Roberts
Yeah, right. So, you'd be kind of putting hydrogen into the wing then, rather than into a discrete tank.
Val Miftakhov
Yeah, yeah. So, there are a few projects like this, but those take a longer time, because you have to design the aircraft, you have to design the propulsion system, you have to integrate, then you have to certify the whole thing.
David Roberts
Yeah, I assume the FAA is — I assume there are lots of hoops to jump through when you're coming up with a brand new plane.
Val Miftakhov
Exactly. So, my big vision here is to transition the entirety of aviation to this new type of propulsion. But the first transition, however small the aircraft is commercially viable, commercially relevant aircraft, is going to be a huge step.
David Roberts
Yeah.
Val Miftakhov
So, what I wanted to focus the company on is to say, "All right, what's the smallest relevant scope that we need to take?" And it will already be a huge amount of work, but what's that scope that we need to take in order to jumpstart that transition? And it turns out to be engines, initially for existing aircraft, because then I don't have to prove to the regulator that the aircraft is good. That's already done. I just need to replace the engine. And by the way, replacement of the engines happens all the time in the industry because new engines become available and manufacturers say, "Okay, we're going to re-engine the aircraft. We're going to certify what's called the supplemental type certificate for the aircraft with a new engine."
That's being done in the industry. So, I'm riding the existing processes in the industry to do it. You know, you mentioned automotive as a comparison. As we talked, I think in the middle, a typical airframe outlasts several sets of engines. So, as a result, these markets are different, these very structured markets, very different.
David Roberts
The engine market and the plane body market?
Val Miftakhov
That's right. In automotive, there is no distinction because everything is monolithic. Here, you have, even if you look at the companies in the aviation space, aircraft manufacturers and they don't make engines. Okay. And you have engine manufacturers; they don't make aircraft. Okay. Because these two are different. And even if you go to operators like airlines like United, American, and all those people, they buy their aircraft from Airbus, for example, they buy their engines separately from Rolls Royce and the others. And yes, they come together at the factory, at the Airbus factory, but these are different contracts.
David Roberts
Interesting. So, you are not, you have no plans to become a plane body maker. You're just going to put these engines in. But you assume like, I guess the plan here is like you put these, a bunch of these in small planes, a bunch of small planes fly around with them, everything's fine, it shows people it can work and then sort of like that flywheel accelerates a little bit. And you expect other plane body makers to start sort of designing to this.
Val Miftakhov
Yes, absolutely. And we already have some projects like that, and we hope to become the largest manufacturer, designer, and manufacturer of this new generation of propulsion for aviation.
David Roberts
So then, in this bright future, you know, you're hitting, you talk about sort of like hitting kind of the limits once you get up to like a single aisle plane. But if you could design even larger jets, like if you could design the full size jets top to bottom around electric propulsion, just so they're lighter, maybe different shape, maybe wing body, whatever it is, theoretically you could get the biggest planes on hydrogen like in the future if you combine innovation in the engines and innovation in the bodies.
Val Miftakhov
Correct.
David Roberts
So, there's no remainder in your mind? There's no remainder. There's no part of aviation that's out of reach of this.
Val Miftakhov
That's right.
David Roberts
That's happy-making. We're sort of out of time. But I did want to ask you, this is again another huge topic. But just like we say just a few words on it, there is, you know, people who talk about electric aviation generally, these engines, "engines", today at least have less range. And so kind of the parallel conversation that goes along with electrifying aviation is restructuring how and where people fly. Because right now, like, there's a lot of — this is sort of one of the things I learned from Kyle.
It's a lot of like packages, go on a big jet and you take a very circuitous route to where you're going because you're flying to big airports, basically. So, if you had just smaller planes, you could have a lot more airports. They wouldn't have to be as big and they could be spread out more and you do a lot more short hops. But then, for your vision to work, you also have to throw in refueling, which is when it comes to highly compressed liquid hydrogen, not necessarily a small thing. So, maybe just say a few words about how you envision the air system, the airport system, the flying system evolving around this.
Val Miftakhov
Yeah, we definitely see a lot of this. Like Kyle mentioned, and I know Kyle — a very good company. Probably one of the most practical new aircraft companies out there.
David Roberts
Love that guy. One of my favorite pods I've ever done. I love talking to him.
Val Miftakhov
Exactly. So, I think I agree with him that we are going to move more to point-to-point. A lot of smaller locations. A lot of the connectivity improvements in the smaller communities through this, partially because of the much, much better economics of the small aircraft on electrified propulsion versus on fossil fuel propulsion.
David Roberts
Is that just like less wear and tear, less maintenance?
Val Miftakhov
Yeah. Right now, we're super early on the hydrogen journey. And if you look at the economics, fundamental economics of green hydrogen and renewable hydrogen, your marginal cost of the molecule wants to go to zero. Meaning that we already have this with renewable power. You put a solar farm in, and the incremental cost of any — after you put a solar farm in — incremental cost of a kilowatt hour coming out of those solar panels is pretty much zero. You need to clean them periodically. You don't use any fuel. For electrolytic hydrogen production, it's the same because again, it's almost like a fuel cell. You don't have any moving parts.
You put capital expense in, and then it just works for tens of thousands of hours.
David Roberts
And you're talking about electrolyzers. So, you envision these smaller regional airports having hydrogen electrolysis on site?
Val Miftakhov
It doesn't have to be on-site at every airport. So, we have this concept of airport clusters. And as I mentioned, right, we sold already thousands of these engines. Every time we go to the operator and make those deals, we actually study their networks and we build the fueling network as well or plan for the fueling network. So, we have this concept of clusters of the airports that tend to be sort of within, let's say, a couple of hundred miles radius. And there is an anchor production site within that cluster that we start with and then you produce there and you can deliver to the other airports and as the traffic grows, then you can put one more production site in that cluster and then you go from there.
Right. But you don't have to have production at every single one. So, you move to the network that is much more local, much more point to point, and generally smaller aircraft. And in fact, actually, we've seen that already in the current aviation market over the last 10, 20 years. We've seen that movement already.
David Roberts
Yeah, just for operational reasons, operational savings?
Val Miftakhov
Well, people like to not connect. It's shorter. It's less time. And as you grow the traffic density, you have more and more opportunity to go direct. And you see, you know, 20 years ago, A380, the biggest aircraft out there, was a big deal. 747, a large aircraft, was a big deal. And now those aircraft don't really fly. Well, we don't produce them anymore. And they're being phased out in favor of aircraft like 787, 737, which go direct to point to point. So we're already seeing that. And electrification will accelerate that move.
David Roberts
And I'm assuming, like, electrolyzing hydrogen is electrolyzing hydrogen, hydrogen, hydrogen. So, there's a lot of people out there who are thinking about electrolysis and working on electrolysis of hydrogen. Are you messing with that at all? I did see one press release where you are working on some kind of AI to improve electrolysis. Like, are you getting involved — that's a whole industry to itself — are you getting involved in that at all?
Val Miftakhov
Yeah, we're not getting involved in the electrolysis technology itself, but the way it gets integrated into these on-airport production assets, because it's connected to the aircraft and to the airport environment, we know a lot about it. We have actually already built three locations at airports, our own fuel production.
David Roberts
Oh, interesting. You are electrolyzing hydrogen for yourself now, already.
Val Miftakhov
That's right. Now, we, of course, buy electrolysis equipment and all that. We don't make any of that, but what we do is that we put it together at the airport with a little bit of battery capacity so that we buffer energy with a little bit of renewable capacity and connect it to the grid, and then we can manage the production of hydrogen so that hydrogen comes out at a lower cost. In that segment, we see ourselves as kind of building the blueprint of how this should be done and then offloading that blueprint to the energy folks, the utilities, the energy providers out there so that they can build more of these.
David Roberts
Are you banking at all, in terms of your business plans, et cetera, on substantial reduction in the cost of electrolysis, or is that just kind of a fixed quantity for you?
Val Miftakhov
We expect electrolysis cost to go down quite a bit, but already today, we have, I think, definitely more than 10 contracts. I think it's around 15 or so and growing worldwide on supply of green hydrogen from various producers at costs — that we can deliver to the or they deliver or we can deliver to the airports. It's not uneconomical. But the point is that the costs that we're able to contract are already getting to break even with jet fuel.
David Roberts
Oh, interesting.
Val Miftakhov
Yeah, and partially we are able to do this for aviation, especially for small aircraft, much sooner than for cars and definitely sooner than for heating because of much higher efficiency difference. Yeah, and aircraft fuel is not cheap. It's a relatively highly refined fuel and it goes through all kinds of controls and everything. So, it tends to be relatively expensive. So, it's easier to break even against that. Much, much easier than for example for a diesel truck that has a very efficient Cummins diesel engine. And diesel cost is relatively low. So, break-even situation is much harder for hydrogen over there compared to aviation small aircraft.
David Roberts
Goodness. This is a lot to chew on. Super fascinating. I hope maybe next year I can take a zero-carbon flight. When you envision the timeline of making it all the way up to Boeing 747, say the single-aisle jets, like when ideally in your plans, when is that? Is that in my lifetime? Am I going to be able to fly a zero-carbon passenger flight between two major cities before I die?
Val Miftakhov
Yes. So, I think from the technological perspective, we will have the technology to power a 737 size aircraft, which is a 200-250 seat aircraft, in around 10 years.
David Roberts
What a time to be alive. Okay, well, we could go on forever, but this has been super fascinating, tons to chew on. So, Val, thank you so much for coming on and walking us through it.
Val Miftakhov
Thank you, Dave. Appreciate it.
David Roberts
Thank you for listening to Volts. It takes a village to make this podcast work. Shout out, especially, to my super producer, Kyle McDonald, who makes me and my guests sound smart every week. And it is all supported entirely by listeners like you. So, if you value conversations like this, please consider joining our community of paid subscribers at volts.wtf. Or, leaving a nice review, or telling a friend about Volts. Or all three. Thanks so much, and I'll see you next time.
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