- Hydrogen, ladies and gentlemen, is the new frontier. - Clean hydrogen is gonna help us meet this goal. - What's going on in the development of hydrogen aviation engines and why does it seem like a rift is opening up between the US and Europe? Well, to explain that, I will have to bring you into a really fascinating and complicated world where not everything is what it seems. Stay tuned. (calm music) The decarbonisation of the aviation industry remains a really hotly debated topic.
The industry aims to develop a path towards a net zero carbon footprint by the year of 2050, and while that might sound like it's a long way into the future, it really isn't. Obviously, for that to be possible, we need new technologies that will both mature and practical enough by 2050, but that's only one part of the problem. You see, an airliner that is entering service right now will very likely still be in service in 2050, because that's just how long the life cycle of a normal aircraft is. So this means that new aircraft technologies are not enough.
We also need to have a concrete game plan that will allow us to start decarbonising our current aircraft as well for this to work. And the only realistic plan we have for that involves the use of something known as sustainable aviation fuels or SAF. As I have explained in previous videos, the composition of these fuels is actually very close to the aviation fuels that we are already using today. That's really good news, because it means that current jet engines are already compatible with these fuels, but there is a catch here.
Whilst the engines themselves may be compatible, that doesn't mean that we could actually constantly burn 100% of SAF in our current engines. You see, the problem isn't really the engines themselves. Instead it's the whole fuel system. Now, I have made a video explaining this in detail, but the gist of it is that sustainable aviation fuels contains much fewer aromatic hydrocarbons, or soot, in other words, than normal jet fuel does.
Now in many ways, that reduction is a really good thing, because it means that under the right conditions, SAF fuels could generate 50% to 70% fewer contrails for example. Now contrails are obviously just water, but soot acts as kind of a catalyst that enables water to condensate onto the droplets that form these contrails. And since contrails can effectively trap heat in the atmosphere, reducing them potentially helps fighting climate change.
But these aromatic hydrocarbons also serves a very important role in our current aircraft. You see, it turns out that many parts in the fuel system, like the rubber seals in fuel tanks and pipes, actually need these aromatics in order to stay soft and maintain their sealing properties over time. And that means that while burning 100% SAF would probably work okay on an aircraft if we did it from time to time, in practice, regulators today will only allow commercial flights to run on fuel with a maximum of 50% SAF. The rest has to be regular old jet fuel. But obviously this is not an impossible problem to solve. Designing new kinds of rubber seals is doable, and both Boeing and Airbus have committed to both developing and certifying such upgrades for their existing aircraft to allow them to operate safely with 100% SAF by the year 2030.
Now, at this point, I know that some of you are looking at the title of this video and wondering, well, if sustainable aviation fuels are an option and making them fully compatible with the aircraft that we fly today is just a matter of changing a few seals, then why would we even bother with hydrogen? Well, the answer to that has to do with how we get SAF today and how we can scale it up in the future. Because frankly sourcing SAF today in any kind of volume is so difficult that in practice, we are nowhere near that 50% maximum limit that I mentioned before. Here, it is probably worth clarifying what makes sustainable aviation fuel sustainable; in other words, how these fuels differ from other kinds of biofuels. Well, basically the simple rule is that the creation of SAF should not compete with normal food production. This means that SAF manufacturers should not use prime agricultural land or food crops as SAF feedstock unless SAF is made by the use of waste products in food production. SAF production also shouldn't compete with food production when it comes to the availability of water and there are more restrictions to help with land conservation efforts as well.
This is one reason why scaling up SAF production is so challenging, especially to the enormous volumes that the aviation industry needs. Finding enough source material to make this stuff is just very hard. For example, it is possible to make SAF from used cooking oils from deep fat friers, but even if we all collectively would decide to live only of deep fried everything, we still wouldn't be able to generate enough SAF that way.
And if we tried, we would then have to work out how to gather all of that used cooking oil, transport it somewhere where it can be processed in volume and do so profitably. Now fuel companies are coming up with more and more ways of creating SAF, for example by processing landfill materials, algae and an increasing variety of other feedstocks, but they always run into the same problem. Coming up with a way to scale up these processes involves creating completely new supply chains and doing this persistently and sustainably isn't easy. And then we come to the cost of sustainable aviation fuels.
Now this currently varies wildly from place to place and depending on the method used to make the SAF, but as a rough guide, SAF is currently at least two to two and a half times more expensive than conventional jet fuel. Now that cost should eventually drop significantly if we manage to scale up SAF production enough, but that's a really big if. And I would like to give you some figures just to put this into context here. In 2022, the aviation industry in the United States consumed 59.8 million liters of SAF.
That's 15.8 million gallons. Now that sounds a lot until you compare it to the amount of conventional jet fuel that was used in the US during that same period, which was 44.9 billion liters or 11.8 billion gallons. This means that the SAF usage in the United States in 2022 was only around 0.1% of the total fuel usage in the industry.
Now I don't know whether or not that was close to the maximum production capacity of SAF that year, but I'm sure you can start to see the problem here. Another way of thinking of it is that if we would suddenly increase SAF usage 100 times over, we would still only be at around 10% of the fuel that we need. With that, you can probably see that that 50% limit in SAF usage in current aircraft isn't very limiting at the moment. Now there is more to SAF including more ways to make it and it still has many advantages for sure, but the many problems with it is a big reason why there are many in the industry who believe that hydrogen will ultimately be the way to go at least for a big part of commercial aviation.
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Back in September of 2020 Airbus announced the launch of what it called the ZEROe project. At the time, this was basically a series of hydrogen-powered concepts and the reason they presented several of them was because Airbus didn't really know which kind of hydrogen propulsion it should go after. Broadly, speaking there are two ways of powering an aircraft with hydrogen.
The first option which theoretically is closest to the technology that we already use is to burn hydrogen in the same kind of jet engines that we have today. The other option is to use hydrogen fuel cells to generate electricity which will then be used to drive electric motors that will spin propellers or fans and both of these methods have both advantages and disadvantages. Hydrogen combustion in jet engines is the lighter of the two options but fuel cells are more efficient overall despite being heavier as an installation. Now obviously the weight penalty has efficiency implications but the additional efficiency of the fuel cells more than makes up for it.
Also modifying existing jet engines so that they work with hydrogen brings some less obvious challenges. You see hydrogen burns with a higher flame temperature compared to regular jet fuel or SAF. So in practice, this means that a converted jet engine would probably generate less power than the conventional version because of temperature-related limitations. That could be a problem particularly during takeoff and climb but there might actually be a really cool way around that. You see there is a company called Derwent which is working on a type of dual-fuel combustor that would enable current jet engines to run both on regular jet fuel and hydrogen. The idea there would be to use jet fuel during takeoff and climb when the aircraft needs higher power settings as well as during landing in case of a go-around and the aircraft would then switch over to hydrogen in cruise where lower power settings could do the job, kind of like how a hybrid car works today.
Derwent believes that it will even be possible to adapt an existing aircraft like an Airbus A320neo with cylindrical tanks under the wings to hold the liquid hydrogen. Such an aircraft would basically retain the vast majority of its existing systems with minimal changes so in theory, at least, it could be certified more easily. And by the way, we need cylindrical tanks for hydrogen because it isn't really possible to store hydrogen inside of the wings of our airliners like we do with conventional jet fuel.
Hydrogen needs to be kept at extremely low temperatures which means that the tanks needs to be insulated and cooled and hydrogen also has a nasty tendency to leak, being that it is the smallest atom in the periodic table. This also means that hydrogen is very light so for a given weight of fuel, hydrogen has about three times the energy of jet fuel. But it also needs a lot of volume and obviously, the insulation required for the tanks adds weight as well. So the size of these cylindrical tanks under the wings would have to be a compromise between weight, volume and range of the aircraft. The available hydrogen on board would only be enough for a relatively short flight but that's not necessarily a problem. Typical flights of single aisle jets like the A320neo are often just a fraction of the plane's maximum range so for flights between 800 and 1000 nautical miles in length, Derwent claims that this mixed fuel A320neo would burn 50% less CO2 than a conventional jet would.
And, of course, it could then still be used for longer flights using conventional jet fuel or SAF. Now, I think that this is definitely an interesting idea and perhaps even a way to retrofit existing airliners for these new fuels and if it can be introduced more quickly than other hydrogen projects this could be a good way to kickstart hydrogen supply at airports, which is another issue I'll get back to soon. But a modified Airbus A320neo that can also burn hydrogen is not really what Airbus promised with its ZEROe project. Instead that project is meant to introduce an all new aircraft and from the start, Airbus aimed to bring that first all-hydrogen airliner into service by around 2035.
At least that's what Airbus wanted in 2020. And as far as I can see on their website, 2035 still remains the target. But is that really realistic? Well that's where things get a bit more complicated because at some point, Airbus needs to commit to a method of hydrogen propulsion either hydrogen combustion or fuel cells. Back in March this year, Airbus stated that it aimed to make a decision on which method to go for by 2026 or 2027 at the latest which would give them around eight to nine years to develop that new jet and frankly, that's cutting it a bit tight in my view.
I have covered the pace of aircraft development in recent videos and despite all of our technological innovations in the industry, development time is actually going up not down. So I'm not sure an eight-year development cycle for an aircraft that uses an entirely new type of fuel is even possible but maybe I'm wrong. Let me know in the comments what you think about that and while you're down there, please like and subscribe. Anyway to commit to a specific propulsion method, hydrogen combustion or fuel cells and to finalize the rest of the configuration of their first hydrogen aircraft Airbus obviously needs all the help and input that they can possibly get from the engine manufacturers out there. And this is where Airbus are getting a little bit uneasy with the difference in attitude towards hydrogen between the two sides of the Atlantic, the attitudes of engine makers to be precise. You see it turns out that Airbus are looking for a little bit more development input on hydrogen from American jet engine manufacturers in particular from General Electric and Pratt & Whitney.
But their limited input doesn't mean that these companies aren't working on hydrogen at all; far from it. General Electric is part of the CFM engine partnership and through that, they are working with Airbus on hydrogen research. Actually, the first jet engine that Airbus will run on hydrogen in flight will be a GE Passport engine.
For that test, Airbus will mount this modified engine on a special pylon fitted to the side of the fuselage of an Airbus A380 which looks really odd but also kind of cool. Pratt & Whitney is also doing some research on hydrogen propulsion, specifically to make hydrogen combustion much more efficient by recovering and reusing water that is produced as the engine runs. This has to do with clever ways managing the heat in these engines. Remember hydrogen is stored in cryogenic temperatures and then heated before it enters the engine so there is a lot of energy to be lost and gained in managing this process as well. Pratt & Whitney calls this project the Hydrogen Steam Injected, Inter-cooled Turbine Engine or HySIITE. And if you want to learn more about that, as always, I'll suggest that you check out Bjorn Fehrm over at Leeham News.
But if Pratt & Whitney and General Electric are doing this then why is Airbus kicking up a fuss? Well, the reality is that even with this work the two American companies are doing only a fraction of the work that European companies like Safran, Rolls-Royce, MTU and other entities are doing. And this doesn't seem to be a coincidence. As I'm sure many of you have guessed, the difference in hydrogen research between Europe and the United States has a lot to do with differences in investment and funding from governments and national institutions. Now I know that that can be a bit about touchy subject for some but to be clear, one way or another, public investments on new fuels for the industry will be absolutely necessary.
The reason I made such a long introduction talking about sustainable aviation fuels in this video is because many in the United States see SAF as a far more realistic way of decarbonizing aviation. But the reality is that this is kind of a false dilemma. Not only do we need more spending in both SAF and hydrogen since our 2050 net zero carbon goal is beginning to look very shaky. We also have to think about the cost of the fuel itself. Hydrogen made using renewable energy which is often called green hydrogen is not very cheap to produce today. But it is cheaper than sustainable aviation fuels and will be a lot easier to scale up.
After all, hydrogen is the most abundant element in our universe. So if in the long term we know that hydrogen is going to be considerably cheaper than SAF to produce in volume, does it actually make sense to spend more funding on SAF, the more expensive fuel? Well, there are three main reasons why Airbus wants American engine-makers to do more on hydrogen. Firstly, beyond the considerable work required to develop the actual aircraft, there are also challenges in adoption of hydrogen as a fuel which go far beyond that.
You see, aircraft can't use hydrogen unless the fuel is widely available at airports and Airbus has been pursuing agreements with a lot of airports around Europe, the United States, Canada and elsewhere for this very reason. But airports obviously can't sign on for this without government support. Secondly, Airbus wants General Electric and Pratt & Whitney to up their game because they basically want more options to choose from beyond Rolls-Royce, Safran and MTU. Rolls-Royce has done a lot of development work on hydrogen including engine testing on the ground, but it is always a good idea to have more talent at hand especially if one or more companies would change priorities. For example Rolls-Royce recently decided to shut down their electrical propulsion arm and concentrate on their core activities after having faced some hard financial times during the pandemic. And thirdly, Airbus also believed that there is geopolitical dimensions to all of this.
China has its own net-zero emission targets with 2060 as the goal instead of 2050. And hydrogen will inevitably be part of these plans. Now there's obviously a lot more to cover here. For example, some analysts argue that the cost of sustainable aviation fuels would be easier for the airlines to absorb in the long run than what other studies on the topic suggest, but it will take time.
Analysts like Price Waterhouse Cooper don't expect SAF to get significantly cheaper before the year 2040, for example. Now one of the more promising ways to scale up SAF production is by using carbon capture from the atmosphere which is something called synthetic SAF or eSAF. But one of the steps in creating this fuel is generating hydrogen which tells you a little bit about how the cost of this method compares with the cost of just making green hydrogen. Finally, I should add that Airbus believes that it's not just commercial aviation that will ultimately embrace hydrogen. Other vehicles could end up using it as fuel as well and generating green hydrogen could become a widespread way to take advantage of excess capacity in solar power installations for example.
But even though hydrogen is more difficult to use in aviation than sustainable aviation fuels, the broader challenge, the generation, transportation and storage of hydrogen could be even harder still. Ultimately, that I think is why Airbus is getting quite anxious right now. They want to see the creation of the hydrogen supply change process start preferably before they even launch their first real ZEROe aircraft which is something that I completely understand. So what do you think? How soon are we really going to see airliners running on hydrogen or do you think that it will even happen? Let me know in the comments here below or join my Discord Server and discuss it over there. And do you, by the way, know that me and one of my best friends, Ben, have created a virtual Boeing 737 type rating course? Well, we have and in it, over the course of more than 10 hours, we explain in detail exactly how we operate the Boeing 737 and it is perfect for anyone with a home simulator or someone who's just interested in aviation.
If you wanna check it out, then use this QR code up here or go to virtual737course.com. Now, check out these videos next and have an absolutely fantastic day. Bye bye!
2024-10-26