View source for SGU Episode 878

=== Sustainable Jet Fuel <small>(17:41)</small> ===
* [https://theness.com/neurologicablog/index.php/sustainable-jet-fuels/ Sustainable Jet Fuels]<ref>[https://theness.com/neurologicablog/index.php/sustainable-jet-fuels/ Neurologica: Sustainable Jet Fuels]</ref>

'''S:''' All right guys let's talk about sustainable jet fuel. Jet fuel is one of those things where that's going to be very difficult to replace the fossil fuel component of it, because all electric jets won't have the range that we really need because all the electronic components are extremely heavy and you know the battery, batteries would have to be extremely, extremely massive and so, like we're nowhere near having the you know electronic and battery technology we would need for long-distance electronic jets, electrical, you know, all-electric jets to be viable. 

'''E:''' We don't have an extension cord that long.

'''S:''' Yeah so you have to burn some high energy fuel, right? The other thing you might think is, well why not just burn hydrogen, right? You can burn hydrogen with oxygen, make water, no fossil fuel. That may also be like a short to medium range kind of option. But the thing is, even the most energy dense form of hydrogen, like liquid hydrogen, is nowhere near as energy dense as fuel, as like jet fuel or gasoline. So, it also just doesn't work, the numbers don't add up. So the best we may be able to do is biofuel for jet fuel. And I'm not a big fan of biofuel because I think─

'''B:''' Takes up too much land right?

'''S:''' ─takes up a lot of land, it's not very efficient, all the reasons you know of why agriculture uses up a lot of resources. The net energy you get out of it, I mean there was a while, you know, back when we first started doing this podcast, the question was is it even a net energy producer? Or do you put in more energy than the biofuel you get out of it, right? But at some point we did cross the line in terms of just efficiency and making bio feel like a gallon of biofuel uses less than that in energy to make, so there is, it is a net producer of energy but still not by a whole hell of a lot. So the bottom line is we're not going to run our civilization on biofuel, right? And I don't think it's really a tremendously good option in terms of like if you can if you compare it to hydrogen fuel cells or just electric like battery electric vehicles. So I just don't think it's going to be like the solution to reducing the carbon output of the transportation industry. But jet fuel is the one niche where I think we need the high energy density of actual fuel and that you could burn and biofuel probably is the best that we can do. Although even there we may not be able to get to a 100% biofuel. But anything we could do to reduce the fossil fuel component would be tremendous. And, I learned something else recently. Again, this is one of those situations where you know how like there's a problem you didn't know exist and you learn about it when the solution to the problem is being proposed.

'''B:''' Yeah I love that.

'''S:''' Yeah it's like, you know that problem you didn't know was there? Well here's a solution to it. But the thing is actually that people don't talk about the problems until they have a solution. Like oftentimes we talk about this, when we, when we're reporting technology news, it's so common to just gloss over the deal killers and not even mention them, you know?

'''B:''' Yeah.

'''S:''' They want, anyway, so we always have to go searching for that so with, with jet fuel, jet fuel requires something called aromatics as an additive to the jet fuel.

'''E:''' So it smells nice.

'''S:''' Yeah well the aromatics exist for a very specific reason. And that is to swell the o-rings which seal the different metal on metal components of the combustion chamber for example, that were for the, for the jet engine. Again not, not, again unless you're a jet engineer why would you know about this thing? But you know just something you don't hear about.

'''B:''' Yeah I never heard about that.

'''E:''' I haven't heard of the o-rings since the Challenger.

'''S:''' Yeah it's the same thing, it's the same thing it's with their o-rings, right?

'''J:''' But think about the engineering behind that, without just that you know I don't know, I wouldn't say discovery but they had to come up with a way to make those seals function. And you know the the gases that are in those tanks actually transforms those seals to to expand to make them function, you know that that's a feat of engineering that had to be created in order for this system to work.

'''S:''' But, there's a downside to the aromatics that they add to the jet fuel and that is that they produce a lot of the carbon and pollution. In fact they're a major component of the contrails, a major component. And, did you know that you know by some estimates the contrails that are produced by jets contribute more to global warming than the CO<sub>2</sub> released by burning the jet fuel.

'''E:''' We may, we're not going to call them chemtrails because of that, okay, good good okay.

'''S:''' Contrails, they're not chemtrails. All right so now here's the solution to this problem you didn't know existed, right? So lignin-based jet fuel LJF lignin-based jet fuel, you guys remember what lignin is l-i-g-n-i-n?

'''B:''' Is that like this part of a tree?

'''S:''' Yeah it's part of wood.

'''B:''' Yeah baby. ''(Evan laughs)''

'''S:''' And so they harvest the lignin from agricultural matter you know and again this is like one of the the only time where I  think biofuel is really plausible, is if you're getting it like, if you're growing corn to make biofuel, you know that's a waste of land. But if you're just using the parts that you would otherwise throw away or the waste, like wastage, agricultural waste then that becomes more plausible. And or if you're like growing it in vats somewhere, where you're not using arable land, you know, that's okay. So this is using agricultural waste you know they, they harvest the lignin and they make an additive to the jet fuel. And it does a couple of nice things. One is that it has the same effect as the aromatics so it can completely replace them. Which would reduce the pollution and the global warming effects of the the the jets. And two it increases the energy density of the jet fuel.

'''B:''' Whoa.

'''E:''' Oh you get more bang for your buck.

'''S:''' Get more bang for your buck.

'''B:''' How the hell does it do that?

'''S:''' It's just high energy, high energy chemicals, you know? 

'''E:''' What's the downside?

'''B:''' Causes cancer if you look at it?

'''S:''' You have to carry less fuel which again, when you're flying it's all about weight, right? So if you're carrying less weight in fuel then you have to, you burn less fuel because you're not carrying as much weight.

'''E:''' Jay we don't have to pay a hundred dollars for that second bag of gear anymore.

'''S:''' Yeah anything, yeah, I mean not only is it good for the environment, anything that makes the commercial jet industry more efficient is good for ticket prices of course.

'''E:''' Definitely.

'''S:''' They recently did a test at 10% lignin based jet fuel.

'''B:''' Damn, 10%. 

'''S:''' 10% blend. But they are, they think think they can get up to 50%.

'''B:''' What.

'''E:''' Whoa, half? Half? That's exciting.

'''S:''' So they're going to continue, they're going to continue testing and do higher and higher blends and again they're planning on testing up to 50%.

'''E:''' How abundance is is lignin?

'''S:''' It's very abundant, it's just in plants. 

'''E:''' Okay so, we're not gonna have a shortage someday of that.

'''S:''' It's a high amount in wood but it's in lots of plants, it basically gives it like its structure.

'''B:''' How could it be, how could they even entertain the thought of 50%? Wouldn't that just eviscerate the power, I mean the energy, the energy density. I mean I would, I mean why not make it 100% then? I mean if if the lignin is so energy dense, can we use that as a fuel for maybe other things? I mean...

'''E:''' What kind of corrosion and stuff is this doing to the engine?

'''S:''' I don't think that's, I don't think that's a problem but again from my reading Bob, the, they're looking for a jet fuel that could be used in existing jet engines. You probably could redesign the engine to fly entirely off of lignin-based jet fuel. But if you want to use it in existing─

'''B:''' Gotcha.

'''S:''' ─you gotta do a blend. And of course that would be massive, you can't just say okay we're gonna replace all the engines on all the you know all the jets that are out there in order to use this new thing.

'''B:''' Maybe they will some day.

'''S:''' Right it's like if you're using a like a corn, an ethanol blend in your car you want it, it wants to be usable in regular cars. Like if you have to have a car, can only use ethanol, I mean they exist, right? There are there, you can make engines that burn pure, pure ethanol.

'''E:''' Or propane like a propane engine that you can make.

'''S:''' But they're but not your regular car but if you wanted to be to fit cleanly into the existing infrastructure yeah you don't you want to be able to function that way. So I think that's why they want to go with a blend. And they're just seeing well how high can we push this and have it still efficiently. So yeah, so it's this, it's a nice little incremental advance you know and it kind of solves. It has these two effects in one where it's replacing the aromatics which is good and it and also increasing the energy density of jet fuel which is good. And it's replacing up to 50% of the fossil fuel you know in the jet fuel, which is good. So that's more sustainable you know, because you're, yes, it's releasing CO<sub>2</sub> and you burn this but that CO<sub>2</sub> was captured recently, you know, in the plant that you're making the fuel out of rather than being previously sequestered fossil fuels that were digging up out of the ground and then releasing into the atmosphere.

'''C:''' Are there, are they concerned about anything unintended?

'''S:''' I didn't see anything you know.

'''C:''' Okay.

'''S:''' Again as we said.

'''E:''' High arsenic levels getting dropped everywhere.

'''S:''' For biofuels I think the the big variable is your feedstock. What do you what's the raw material that you are turning into biofuel? Again like if you are using a─

'''B:''' Truffles.

'''S:''' ─agriculturally intensive crop on arable land and using fossil fuel as your fertilizer base, then that eats away all the advantages of it. But if you're using agricultural waste or if you're farming more sustainably or if you're using a very you know a very efficient crop in terms of land and water use and all that stuff. So it's, I think it really, the big variable is the feed stock.

'''C:''' Yes you really have to look at the entire cycle, you can't just look at the sliver and say this is better.

'''S:''' Exactly, you have to do a total, total life cycle evaluation. So the other thing with biofuels of course is how you're getting from the feedstock to the fuel. That could be an energy intensive process also. If you have to use very high temperatures or whatever and yes if you're like burning coal to make your biofuel, again, it doesn't really help you. But that's why they're focusing a lot on enzymes and you know and bacteria and things that can do it efficiently and at lower temperatures and without having to to burn a lot of energy. And so that's what they're working on here as well. So yeah you have to look at the total life cycle because again very very quickly your right could turn into a net loser if you're not looking at the whole life cycle carbon efficiency, energy efficiency. So but this looks very promising and again something hopefully we'll hear about this again. You know, I'd like to see how this develops. And it would if it all works out and they do it well it'd be great for just hey let's whack back the fossil fuel footprint of the commercial jet industry by 50%. And get rid of another source of pollution, the aromatics that you didn't even know about.

'''C:''' Right.

'''S:''' But we'll see how it goes.