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Hopes For Sustainable Jet Fuel Not Realistic, Report Finds (theguardian.com) 170

An anonymous reader quotes a report from The Guardian: Hopes that replacement fuels for airplanes will slash carbon pollution are misguided and support for these alternatives could even worsen the climate crisis, a new report has warned. There is currently "no realistic or scalable alternative" to standard kerosene-based jet fuels, and touted "sustainable aviation fuels" are well off track to replace them in a timeframe needed to avert dangerous climate change, despite public subsidies, the report by the Institute for Policy Studies, a progressive thinktank, found. "While there are kernels of possibility, we should bring a high level of skepticism to the claims that alternative fuels will be a timely substitute for kerosene-based jet fuels," the report said. [...]

In the U.S., Joe Biden's administration has set a goal for 3 billion gallons of sustainable aviation fuel, which is made from non-petroleum sources such as food waste, woody biomass and other feedstocks, to be produced by 2030, which it said will cut aviation's planet-heating emissions by 20%. [...] Burning sustainable aviation fuels still emits some carbon dioxide, while the land use changes needed to produce the fuels can also lead to increased pollution. Ethanol biofuel, made from corn, is used in these fuels, and meeting the Biden administration's production goal, the report found, would require 114m acres of corn in the U.S., about a 20% increase in current land area given over to to the crop. In the UK, meanwhile, 50% of all agricultural land will have to be given up to sustain current flight passenger levels if jet fuel was entirely replaced. "Agricultural land use changes could threaten global food security as well as nature-based carbon sequestration solutions such as the preservation of forests and wetlands," the report states. "As such, SAF production may actively undermine the Paris agreement goal of achieving greatly reduced emissions by 2050."
Chuck Collins, co-author of the report, said: "To bring these fuels to the scale needed would require massive subsidies, the trade-offs would be unacceptable and would take resources aware from more urgent decarbonization priorities."

"It's a huge greenwashing exercise by the aviation industry. It's magical thinking that they will be able to do this."

Phil Ansell, director of the Center for Sustainable Aviation at the University of Illinois, added: "There's an underappreciation of how big the energy problem is for aviation. We are still many years away from zero pollution flights. But it's true that the industry has been slow to pick things up. We are now trying to find solutions, but we are working at this problem and realizing it's a lot harder than we thought. We are late to the game. We are in the dark ages in terms of sustainability, compared to other sectors."
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Hopes For Sustainable Jet Fuel Not Realistic, Report Finds

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  • by gavron ( 1300111 ) on Wednesday May 22, 2024 @11:42PM (#64492527)

    The push here is actually coming from environmental organizations who think if you simply yell loud enough a solution will appear.

    All of the engines currently in production on everything from an AIrbus A350, Boeing 787, Cessna, AIrbus Helicopters, military aircraft, they all run on some form of petroleum product fuel (Jet-A, JP-8, JP-9, AVGas) and the infratructure of all those underground tanks, piping, pumps, dispensing equipment, and aircraft engines will all need to be changed.

    We went through this in stages with the removal of leaded gasoline. During that time if your vehicle could use unleaded you were lucky to find one of several pumps in a gas station with unleaded fuel. The investment in a new (separate) underground tank and all the rest wasn't going to be recouped without government handouts.

    Changing all aircraft to be emission free or using SAF is beyond unrealistic... it is fiscally unsustainable.
    Today anyway.

    • Green Diesel is a remarkably good substitute for Petrodiesel in all of the ways that Biodiesel isn't, and a little (5%) biodiesel added to it makes it even better for automotive use. I don't see what prevents switching jet fuel up for an equivalent product (without the biodiesel) made from algae. Will it cost more, yes. Is that a show stopper, probably not. There's a bunch of low-lying desert in Texas that isn't doing much of anything now, put open raceway ponds there and fill them with heat pipe-transferre

      • by sfcat ( 872532 )
        You can't use diesel in a jet engine.
        • by MacMann ( 7518492 ) on Thursday May 23, 2024 @01:53AM (#64492651)

          You can't use diesel in a jet engine.

          Two problems with that statement.

          First, jet engines can absolutely burn diesel fuel. https://en.wikipedia.org/wiki/... [wikipedia.org]

          The first axial compressor jet engine in widespread production and combat service, the Junkers Jumo 004 used on the Messerschmitt Me 262A fighter and the Arado Ar 234B jet recon-bomber, burned either a special synthetic "J2" fuel or diesel fuel. Gasoline was a third option but unattractive due to high fuel consumption.[4] Other fuels used were kerosene or kerosene and gasoline mixtures.

          Second, there's a blurry line between diesel fuel and kerosene to a point that the two terms are often interchangeable. https://en.wikipedia.org/wiki/... [wikipedia.org]

          Number 1 fuel oil is a volatile distillate oil intended for vaporizing pot-type burners and high-performance/clean diesel engines.[8] It is the kerosene refinery cut that boils off immediately after the heavy naphtha cut used for gasoline. This fuel is commonly known as diesel no. 1, kerosene, and jet fuel. Former names include: coal oil, stove oil, and range oil.

          Kerosene is #1 diesel fuel, and jet fuel is kerosene, therefore jet fuel is diesel fuel. The US military standardized their fuel requirements so they could use a single fuel in all their engines to ease logistics in a time of war. In peacetime they run their trucks and such on common diesel fuel, because common diesel fuel is cheap and the trucks have diesel engines. I wartime they put JP-8 or JP-5, kerosene type jet fuels, in their diesel trucks. So, again, jet fuel is diesel fuel.

          • by mjwx ( 966435 )

            Kerosene is #1 diesel fuel, and jet fuel is kerosene, therefore jet fuel is diesel fuel. The US military standardized their fuel requirements so they could use a single fuel in all their engines to ease logistics in a time of war. In peacetime they run their trucks and such on common diesel fuel, because common diesel fuel is cheap and the trucks have diesel engines. I wartime they put JP-8 or JP-5, kerosene type jet fuels, in their diesel trucks. So, again, jet fuel is diesel fuel.

            This. Jet engines are turbines so they largely burn any liquid that'll burn... Maybe not safely though (and yes, grossly oversimplified).

            Jet A has an octane rating of 15,
            Diesel fuel has an octane rating around of 15 to 25.
            Regular petrol (gasoline) has an octane rating of 91 (95 in Europe).
            Super (AKI 91) petrol has an octane rating of 98. Can go as high as 100 from some distributors.
            Avgas (aviation petrol) has an octane rating of 100.
            That's why your petrol car will refuse to run on diesel, but it

            • Jet fuel doesn't even need to be a liquid. they can and do run on gaseous fuels. There are even jet engines have even used powdered coal as a fuel.
              Turbines are a part of some jet engines (most common, of course), and ram compression jet engines don't even have a turbine.

              • by BranMan ( 29917 )

                You are, all, wrong. My house, oddly enough, has kerosene heaters. So you *could* say that my house runs on jet fuel. However, SpaceX also uses kerosene. So my house runs on ROCKET FUEL.

                [drops mic] That is all.

        • by dunkelfalke ( 91624 ) on Thursday May 23, 2024 @06:46AM (#64492893)

          Jet engines in general can use anything that burns, even coal dust. The only reason diesel fuel cannot be used in aircraft is because it becomes a gel at low temperatures and the cruise altitude of aircraft is very cold.

          • by v1 ( 525388 )

            #2 diesel gels up in cold weather because they start with #1 (kerosene) and dissolve in ("cut" it with) paraffin (wax) to reduce its cost without significantly affecting its power. Everyone uses #2 in the summer for the lower cost per gallon. If you live iin a cold climate, all the diesel pumps in your area switch their #2 to a mixed #2/#1 for the winter so the drivers don't gel up. Jets would obviously be using straight #1, which is basically kerosene, which is basically jet fuel.

            source: I live in Iowa

            • Yes, my Dad has told me of early diesel trucks having to have a blow torch put on the fuel lines and tank to warm up the fuel to start!

            • The all time record low in Iowa is close to the the typical summer temperature at flight level 350. In winter the temperatures are about the same as on the south pole.

        • Said someone who knows nothing of jet engines. In fact jet engines are remarkably fuel agnostic.

      • by Pinky's Brain ( 1158667 ) on Thursday May 23, 2024 @05:25AM (#64492809)

        Algae at sea have very low yield per area due to lack of nutrients. In open ponds evaporation requires fresh water replenishment (if you flush with seawater you can't add fertilizer, if you replenish with seawater it becomes concentrated brine) and other species which come in outcompete the optimized algae

        The only way to make algae work somewhat is with closed bioreactors and that's likely never going to be as cheap as fossil/biofuel. Can it compete with hydrogen/eFuel? Dunno.

        • Algae at sea have very low yield per area due to lack of nutrients.

          Good thing nobody was talking about using them.

          In open ponds evaporation requires fresh water replenishment

          That might be. But since you don't need a perfect result, you can get the water with direct solar thermal easily enough.

          and other species which come in outcompete the optimized algae

          You're completely wrong about that. The optimal algae colonizes your open ponds for free. [nrel.gov]

          • "The results of the ASP Program suggest that one choice would be to allow the production system to self-select the organisms. "

            They made do with shit strains. In a more natural environment without bubbling captured CO2 it would be worse.

            • They made do with shit strains. In a more natural environment without bubbling captured CO2 it would be worse.

              What they actually found, if you keep reading, was that if you try to breed a better algae then you are wasting time. Nature is better at selecting a strain that will be successful in your local conditions than you are. If you optimize for lipid production you get a strain that grows more slowly, and then you don't actually make more lipids per year than if you just use whatever shows up. This is why the closed bioreactor design is a big waste of time and money which would be better spent elsewhere. Open ra

              • What they found is shit strains was all they had to work with, yes.

                Better genetic engineering still leaves open technological jumps for closed bioreactors (oil exuding species for instance) but for open ponds it's not going to get better than what was possible in the 80s and that likely wasn't good enough.

                • Better genetic engineering still leaves open technological jumps for closed bioreactors (oil exuding species for instance) but for open ponds it's not going to get better than what was possible in the 80s and that likely wasn't good enough.

                  I guess you skipped the part about profitability, where they state that it should be profitable when oil is even cheaper by the barrel than it is now.

    • First you say that changing our jet fuel is similar to the removal of leaded gasoline, something which was difficult but which we did successfully, and then you say that changing our jet fuel is beyond unrealistic and fiscally unsustainable.

      I would argue that getting rid of leaded gasoline was probably much more difficult, since it involved an order of magnitude more vehicles and service stations. At least an order of magnitude more. But the point of the article is that changing our jet fuel is an ineffi
    • AIrbus A350, Boeing 787, Cessna, AIrbus Helicopters, military aircraft, they all run on some form of petroleum product fuel (Jet-A, JP-8, JP-9, AVGas) and the infratructure of all those underground tanks, piping, pumps, dispensing equipment, and aircraft engines will all need to be changed.

      Decades ago a company was marketing biodiesel. Sales guy drove around in a truck that smelled like popcorn when running. Zero mention of needing to change car fuel tanks out. Engine re-design? Sure. Understandable. Ripping up the underground tanks and piping? Not so much. Why again would ALL the infrastructure need to be changed? It’s a gas tank, not a replacement kidney.

    • The push here is actually coming from environmental organizations who think if you simply yell loud enough a solution will appear.

      Electricity comes out of the plug - why do you need all those ugly power plants?

      One of the things the greenies have been pushing for, is deriving aviation fuel from plants. That would work just fine, as long as you don't mind not growing food, given how much land would be required. On, and as long as you ignore the various costs, from plowing, to fertilizing, to transport, to processing. It's like the corn-ethanol scam, only bigger.

      • by q_e_t ( 5104099 )
        You are confusing some with all environmentalists. There are plenty against biodiesel because it doesn't scale and had negative impacts on the environment. Environmentalists aren't a hive mind and many points of view exist.
    • by Sique ( 173459 )
      The whole idea of Sustainable Jet Fuel is to have a drop-in replacement, which has the same physical properties than petrol based jet fuel. There is no need to change anything in the infrastructure or the jet engines. It's the same molecules, just not refined from crude oil, but synthetized from water, carbon dioxide and lots of electricity. And here is the problem: Getting enough waste electricity for instance from windmills or solar panels during overproduction of electricity, or have another, grid indepe
    • by AmiMoJo ( 196126 )

      You misunderstand what environmental orgs are saying.

      Aviation accounts for a bit over 2% of global CO2 emissions, but it's actually a little worse because the emissions are at altitude. Either way, it's an issue that needs addressing.

      It's going to cost money to address it. New technology needs to be developed.

      In the interests of fairness, the people profiting from it should probably be the ones to pay those costs.

    • Changing all aircraft to be emission free or using SAF is beyond unrealistic...

      The point of SAF is that you *don't* change the aircraft. In order to market something as "SAF" it needs to meet ASTM D7566. The primary purpose of ASTM D7566 is to produce a fuel that is re-designated under ASTM D1655. I.e. if you make SAF to the SAF standard you can pump it straight into any engine designed to take Jet-A1.

      And there have already been demonstrations that you can fly a 100% SAF fuel on an intercontinental flight without any changes to the airplane.

    • by Kisai ( 213879 )

      This is why it's better to push consumers to switch to EV's, because they CAN. EV aircraft are more likely to switch back to zeppelin-style aircraft when we run out of aviation jet fuels.

      I do not see an "EV" jet at any point in the future.

    • by tlhIngan ( 30335 )

      Changing all aircraft to be emission free or using SAF is beyond unrealistic... it is fiscally unsustainable.
      Today anyway.

      Well, the problem is there is also no supply for SAF - the feedstock used is basically at capacity - and it's being used for both SAF and biodiesel.

      Anyhow, the push for SAF is because aviation has a very big emissions target on its back. It's not from the airlines - because the fuel per passenger mile is way more efficient in a plane than if everyone drove, or if everyone headed out in a

    • The push here is actually coming from environmental organizations who think if you simply yell loud enough a solution will appear.

      There is also a push from the military. Its a contingency being explored. It does not necessarily need to be an efficient process in this context.

      That said, there is no reason not to engage in a little greenwashing PR while they are at it.
      "'GREEN HORNET' The Navy celebrates Earth Day by showcasing a supersonic flight test of the "Green Hornet," an F/A-18 Super Hornet strike fighter jet powered by a 50-50 biofuel blend over the Patuxent River, Md., April 22, 2010. The test, conducted at Naval Air Station

  • by u19925 ( 613350 ) on Thursday May 23, 2024 @12:17AM (#64492557)

    This was already posted on 05/17. https://science.slashdot.org/s... [slashdot.org]

  • I saw no mention of electrofuels, in some cases also known as Power-to-X technology, which uses electricity (from renewable sources) to turn water into hydrogen. If the hydrogen is not used as-is as a fuel, it can be converted to ethanol, by using captured CO2 (bonus), and thus jet fuel.

    • Railguns if can survive the gâ(TM)s can reduce fuel consumption for launches.
    • Because aviation doesn't want fuel to get 4x more expensive. Hydrogen will get cheap enough, high purity CO2 will be the limiting factor, especially at net zero.

      PS. private pilots are worse, reformulating their leaded kerosene makes you worse than Hitler. Add the costs and Armageddon has come and you are Satan himself.

    • It's a massively inefficient process. Unless there's some sea change in the technology it just doesn't make sense, it would make more sense to use all that electricity to power the grid rather than inefficiently generate electrofuels.

      Or if electricity is in temporary massive oversupply it might make sense, but only if there's no other form or energy storage available.

  • by ishmaelflood ( 643277 ) on Thursday May 23, 2024 @01:44AM (#64492643)

    It's not a great look is it? Taking half of the UK's farmland to grow avfuel.

    • by shmlco ( 594907 )

      Is it even dumber than using 26% of the US grain-producing land to grow corn for ethanol???

    • It's not a great look is it? Taking half of the UK's farmland to grow avfuel.

      No, that would be very stupid and self-defeating. This is on brand for the UK, or at least England, but it wouldn't make any sense (though that is also on brand.) The place it makes sense to grow the feedstock is Africa (the further south the better) and the feedstock that makes sense is algae. In this way you avoid competing with food production even slightly.

  • Hopes For Sustainable Jet Fuel Not Realistic, Report Finds

    No sh*t Sherlock...

    You just need a basic understanding of physics and orders of magnitude to understand why this always was unrealistic. Same as with how some people still think a full solar/wind grid is realistic at scale (not talking about countries with the ability to do enough hydro).

    Believing in Santa Claus will only get you so far. Physics has a habit of eventually knocking on the door to catch up.

  • by devslash0 ( 4203435 ) on Thursday May 23, 2024 @02:38AM (#64492697)

    Posted before a few days ago. Mods, do your job!

  • They don't work cheap, but they work fine. Air freight and passenger flight becoming a little more expensive isn't going to break the economy.

    • by Viol8 ( 599362 )

      Yup, just wave money at the laws of physics and they'll bend to your will. Whatever.

      I suggest you look at the energy requirements of just a single long haul flight and how much agricultural land and/or renewable power it would take to create enough fuel to fill the aircraft tanks.

      • Fossil fuels come pre-loaded with energy, while synthetics have to have it added in. Seems like a no-brainer that fossil fuels are the only way to go for flight...

        When you consider 'external costs', they're even. If you care about not adding carbon to the atmosphere, fossil fuels come with a carbon capture and sequestration requirement that makes them just as expensive as synthetic fuel. Synthetic fuels are closed-loop, extracting as much carbon from the air in their creation as is released in their use.

        • Evidently you believe fossil fuels are too expensive for EVERY use. Was that true in the past? Scour the skies of airplanes now. Then in the past no trains no steamships no cars no electricity no piped hot water. I've pointed this out before. Anti-fossil fuel agendistas want to return civilization to the dark ages ... unable to be productive now, they demand all express their disability. To the regimes of Charlemagne and Longshanks. I guess such super-Luddites expect to be the earls and ba
      • Lets say they burn through 10 TJ a day. It would take ~2500 acres of PV with 50% conversion loss (in prime locations, MENA/Australia/etc) and very approximately double the cost of the plane.

  • Hydrogen as aviation fuel is a joke. People who suggest it as a fuel just aren't considering how difficult and unsafe if would be.
    It's dangerously flammable, it burns from 5% to 90% mixture, petrol only burns at a small range of air/fuel mixtures.
    It needs cryogenic storage, what happens to the fuel left in the tank when it's parked?
    It needs to be stored in the plane body, currently aircraft store fuel in the wings for safety.

    Just think of the logistics, shipping cryogenic around the country, getting it to r

    • Gaseous hydrogen is used in forklifts commercially without subsidy, every major forklift brand offers them. Mostly delivered on site as a liquid, guess forklift scientists > rocket scientists.

      A long term parked plane can be connected to the grid and deliver power back as the hydrogen evaporates if it's impossible to pump it back for some reason. Under normal circumstances the hydrogen will be subcooled (at the pressure in the tank) and will take a while before boiling off even without putting the evapora

      • Gaseous hydrogen is used in forklifts commercially without subsidy, every major forklift brand offers them.

        And because it works in small vehicles designed to be heavy and where it's convenient to refuel often, naturally it's a perfect match for... aviation!

        • No, aviation would use liquid like the tankers supplying the warehouses.

          At net zero all options are shit, that hydrogen is shit doesn't necessarily disqualify it.

      • Gaseous hydrogen is used in forklifts commercially without subsidy, every major forklift brand offers them.

        The problem with hydrogen as a mobile fuel is storage. Forklifts are vehicles with the unique operational feature that they never get more than a hundred meters from their refueling station.

        You don't need to carry much fuel . And it's not really a big deal even if your forklift drops to zero: you just walk back to the fuel station and grab another cylinder.

      • Gaseous hydrogen is used in forklifts commercially without subsidy, every major forklift brand offers them.

        Last I checked the fuel load of a forklift was significantly smaller than the fuel load of an aircraft. Risk and logistic change wildly with volume. Speaking of which...

        Mostly delivered on site as a liquid

        Indeed, liquid. The H2 industry has already considered this option doesn't scale beyond forklifts which is precisely why they are looking towards ammonia carriers, pipelines, and local production.

        guess forklift scientists > rocket scientists

        Yeah, in other news a builder can build a small shed, but you do actually need a structural engineer to build a sky rise tower.

    • Don't forget the weight of H2 tanks. Aviation really needs something lightweight and dense at atmospheric pressure and temperatures encountered at altitude all the way to the ground. And cryogenic liquids aren't it.

    • Hydrogen has a long history of use as an aviation fuel. Here's the most famous example. https://en.wikipedia.org/wiki/... [wikipedia.org]
  • The nomenklatura will still be able to jet off to their climate conferences, fear not!
  • Nuclear powered ocean liners
  • The next question would then seem to be "How do we mostly stop flying?" Musk's hyperloop was looking good until it was pointed out that even small deviations from "absolutely straight" would range between sick passengers from the random motions to splattered passengers if, say, an earthquake displaced the tube.

    Between this and the general inconvenience of flying for a large number of reasons starting with "TSA" and going on down, we might want to look at killing 2 birds with 1 stone by providing a way for

    • I think it'd be more practical to accept that effective air travel (currently) requires burning fossil fuels, and so we should include the cost of carbon capture into the price of the flight.

      That NY to LA flight will burn on the order of a metric ton of carbon per passenger. The cost of durably capturing a ton of carbon varies enormously by method, but the latest figures seem to put it on the order of $100. It'd be a significant increase on a fare that typically costs in the hundreds of dollars, but a t

    • Hyperloop was a stupid idea. There's just too much that can go wrong, drilling tunnels is insanely expensive and despite the elongated muskrat's claims, that company does not have any actual innovation in tunnel drilling.

      Given that 300+ MPH is achievable in ordinary high speed rail, that's what needs to be the NY > LA solution. Air is unavoidable for intercontinental travel, but putting high speed rail in place could reasonably easily replace air for domestic travel, it just needs to be built. And it

    • by skam240 ( 789197 )

      Build it above the current interstate highways so you don't need to solve the land acquisition problem,

      That's an instant fail right there as this would be just as expensive as land acquisition not to mention increased maintenance costs from maintaining so many bridges that will have to be paid out for as long as such systems exist. Rail just isnt a viable solution to global warming emissions in the US due to cost regardless of whether that's driven by land acquisition in already built up cities or an absolutely insane number of bridges. Our limited resources are best spent elsewhere where they would be far m

  • Southeast Asia and China. That is the problem. You can stop all planes and all cars and all electricity in all of North America and that is still the problem.
  • by bill_mcgonigle ( 4333 ) * on Thursday May 23, 2024 @09:07AM (#64493157) Homepage Journal

    Taylor Swift will fly her jet to the nearest microphone to denounce this study.

    Maybe she should instead invest some of her billions into methanol catalysts. There's good work going on there.

    Short-haul might be completely doable with a combo of battery, methanol, and glide-heavy flightpaths.

    That needs new engineering but Madonna is still being a skank at 85 so there's time.

    • Wait, we're hating on Taylor Swift this season? Didn't we used to be hating on Elon Musk for his private jet use?

      Turns out that the number one celebrity for most emissions last year from private jets is Pitbull: 4,549 metric tonnes of CO2 in 396 flights last year. I never heard of him because I'm old, but google tells me he's a famous rapper.

      Travis Scott and Kim Kardashian come in [thrillist.com] at numbers 2 and 3.

  • I hate every time we think about ethanol we decide to use corn. Corn costs the American tax payers way too much and there are better approaches.

    • The corn lobby.
      • you say this in jest perhaps? 97 million acres of farm land in the usa are for corn alone. Enough corn grown to feed 14 people with a 3000 calorie diet per acre. Most of it however is used in biofuel. Second most is for animal feed, again a terrible use of corn since most animals waste the majority of the energy stored in it in the form of poop, burps, and farts, which adds even more to the global greenhouse problem. And of the tiny fraction of corn that is grown for food, the great majority of that is used
  • Ethanol biofuel, made from corn, is used in these fuels

    Nuff said. The corn lobby owns the American Congress. You can rest assured that this will pass and it will be another fiasco like gasahol. Historically speaking, King Cotton was replaced by King Corn, and the amount of money wasted on subsidies meant to "support family farms," but mostly just ending up as corporate welfare is staggering.

    Watch John Oliver's latest report [youtube.com].

    • I really appreciate trying to shine a light on the horrible corn industry but you're not going to win anyone over with john oliver

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