11 ms·

Jet fuel from thin air: Aviation's hope or hype?

97 points by theklub 7y ago

rpmisms 7y ago
Why not just process biomass?
- SketchySeaBeast 7y ago
  The article says those are costly, and the cost would have to be passed onto the consumer. Honestly this feels like it's a feel-good piece "look, we're doing our part!" when the technology is still a long ways away. Better than saying that the airlines are working on teleportation, but I don't know by how much.
- dredmorbius 7y ago
  There isn't enough. Even for aviation alone, which is about 6% of US fossil fuel consumption, using a process Boeing had lauded as a "breakthrough" a few years ago, essentially using a salt-water pickleweed (halophytes), you'd need the entire states of Kansas and Oklahoma, plus considerable chunks of Nebraska and surrounding states, to meet present US demand. We use a lot of fossil fuels. Mind-boggling amounts. And those accumulated slowly over immensely long periods of time, though that's due to inefficiencies both in what ancient biomass was kerogenised in the first place, and the losses in keroginisation (essentially: petroleum formation). Jeffrey S. Dukes, "Burning Buried Sunshine" (2003), lays this out for coal, oil, and gas. For petroleum, we're presently burning about 5 million years of accumulated fossil biomass every year. Or, alternatively, we burn through a full ancient year's biomass accumulation every 6.3 seconds. All biomass, roughly, equates all human and livestock feed, plus some construction materials waste-streams (mostly wood and forestry products). When you say "use biomass", you're really saying "go through the leftovers of humans and livestock". And quite simply, there's not all that much there. Maybe 5-10% of current total energy use if you could efficiently capture the entire wastestream (and keep in mind that it is very widely distributed. In practice, you could probably power waste water treatment plants off of captured biomass, with some surplus left over. But not much more than that.
tedmcory77 7y ago
Sounds very similar to Prometheus Fuels. The AMA thread on here from the founder was amazing.
- detritus 7y ago
  To save anyone else curious the hardship of searching... https://news.ycombinator.com/item?id=19842240 https://news.ycombinator.com/item?id=19842240
tengbretson 7y ago
Sounds like some kind of Fischer–Tropsch process. Starting with CO2 sounds like it would require an obscene amount of electricity though.
- Analemma_ 7y ago
  > Starting with CO2 sounds like it would require an obscene amount of electricity though. It could still be worth it, depending on how/when it was made and how it interacted with the grid. There's an increasing problem right now of too much solar supply during the day and not enough power storage; projects like this could be used to soak up excess power and it would still come out carbon-neutral.
  - MrBuddyCasino 7y ago
    Germany is paying other countries to absorb spikes. Anything that creates value instead looks like a win to me.
comnetxr 7y ago
The question should not be whether this is too costly as compared to jet fuel, but at what carbon price is it cheaper than jet fuel? Once the cost of carbon is at the long term limit, which is equal to the cost of extracting carbon from the atmosphere, then these technologies could be much more cost effective. (But if they aren't, there would be no reason to ban flying, as the carbon price would pay for the extraction of carbon that flying produces.) By not account for how much jet fuel costs with increasing carbon pricing, and by framing the alternative to allowing climate change as banning flying, it seems like the author has completely missed the story..
ajross 7y ago
This always strikes me as missing the point. The end result is fuel to burn. It doesn't matter where it comes from, only what the net carbon budget is. Continuing to burn petroleum in jet engines is fine, as long as it's appropriately offset. There's absolutely no technical reason to need to bend over to implement this kind of setup. Spend those dollars on renewables and sequestering solutions instead, clean up the last 10% of fossil fuel extraction at the end of the process.
- quickthrower2 7y ago
  Lots of people working on different ideas to help reduce CO2 is probably what we need though. We don't know what will be the 'winner' yet, but the more things we try the more likely we are to find the best solution(s).
- dredmorbius 7y ago
  Good fuels are hard to find. The problems with petroleum (and natural gas) are twofold. One is the carbon emissions, but the other is the fact that supplies will eventually run out, and have to be substituted by something. And as we try to pursue every last fraction of petroleum, the environmental costs will rise -- increasingly hard-to-access, high-risk, or heavy-treatment options. Think deep water, Deepwater Horizons, and tar sands and fracking. Hydrocarbons are great fuels, and for some applications, especially powered flight, there's virtually no other viable alternative. Keep in mind that the aeroplane and automobile both appeared at virtually the same moment -- the principle requirements for each were high power-to-weight engines and energy-dense fuels. Sorting out the mechanical and aeronautical problems were relatively straightforward. (Lightweight sturctural aluminium also helped markedly, and also became available largely through the same related set of technological processes providing Otto-cycle engines and petrol-based fuels.)
nickcw 7y ago
Let me get out my back of the envelope for some quick and inaccurate calculations ;-) There are 10.3 kWh of energy in a litre of Jet A1 fuel. Let's assume (generously I think) that the process is about 50% efficient, so it takes ~20 kWh of electricity to make a litre of Jet fuel. Assuming (amortized) solar power is the same cost as grid power ~$0.1/kWh then to make your litre of fuel costs 20 *0.2 = ~$2/litre According to my research Jet A1 costs about ~$0.50/litre. So this is a way off at the moment, however if there was tax on fossil fuels for aviation then this could be competitive.
- markvdb 7y ago
  Depending on how capital intensive the plant is, this might still be cost competitive with intermittent low, zero or negatively priced green electricity.
  - jblow 7y ago
    Also ... renewables are always going through cycles of high and low availability. Prices vary across these cycles. If you make your fuel only at the time during the day when there is the highest delta between supply and demand, then you pay the minimum electricity cost, and the utilities are glad to have you there to balance the load.
    - ThrustVectoring 7y ago
      Note that this economic strategy is already in place in other industries where electricity price is a large component of the final cost of goods sold. Aluminum smelting is a huge example of this.
  - happosai 7y ago
    Large-scale Negative, zero or below-cost renewables only happen if someone else foots the bill. And that usually means tax-payer funded subsidies. I mean sure, there will be some hours during exceptionally sunny/windy days when price is less than the production cost, but don't bet your business on it. What does work is building the plant in a wind/solar abudant location and co-siting with large, behind-the-meter wind/solar plant. Not only do you get electricity at cost, but you cut the grid costs and taxes away too.
vilhelm_s 7y ago
I guess a more low-tech approach would be to fuel jets with ethanol. Googling a bit now, the U.S. uses about 18 billion gallons/year of jet fuel[1], and produces 17 billion gallons/year of fuel ethanol [2]. The price per gallon is about $1.5 versus $1.94 [3,4]; because jet fuel has 46% higher energy density that means that the cost per Joule would increase by a factor of 1.9. Obviously this is only a back-of-the-envelope thing, but it seems that even if we switched to renewable fuels using the technology that are available today, ticket prices should about double. Historically, that corresponds to going back to circa-1980 prices[6], which I guess is bad, but not exactly apocalyptic. [1] https://www.eia.gov/todayinenergy/detail.php?id=31512 https://www.eia.gov/todayinenergy/detail.php?id=31512 [2] https://www.eia.gov/todayinenergy/detail.php?id=32152 https://www.eia.gov/todayinenergy/detail.php?id=32152 [3] https://markets.businessinsider.com/commodities/ethanol-price https://markets.businessinsider.com/commodities/ethanol-pric... [4] https://www.indexmundi.com/commodities/?commodity=jet-fuel https://www.indexmundi.com/commodities/?commodity=jet-fuel [5] https://en.wikipedia.org/wiki/Energy_density https://en.wikipedia.org/wiki/Energy_density [6] https://www.theatlantic.com/business/archive/2013/02/how-airline-ticket-prices-fell-50-in-30-years-and-why-nobody-noticed/273506/ https://www.theatlantic.com/business/archive/2013/02/how-air...
- ulfw 7y ago
  You answered your own question. " jet fuel has 46% higher energy density" That's why. Few things matter more when lifting things into the air than weight.
  - vilhelm_s 7y ago
    I guess the current long routes would not work, but apparently airliner fuel efficiency improved by almost exactly this much since 1980 (https://www.greenaironline.com/news.php?viewStory=684 https://www.greenaironline.com/news.php?viewStory=684), so it still seems that's the era we'd go back to...
- throw_into_air 7y ago
  The problem with ethanol is it absorbs water, which at greater altitudes (lower temperature and pressure) freezes and blocks fuel lines. For that reason aviation fuels have limits on ethanol content.
leoedin 7y ago
The jet fuel part of this is a distraction from the important (and hard) part - turning electricity into usable liquid fuel. Electrolysis is easy enough, and there's plenty of places with enough water. Then you have hydrogen. Hydrogen is not nice to work with, store or use, so you want to turn it into something else a bit nicer. The problem is, almost all practically usable liquid or gaseous fuels contain carbon. Where do you get that from? The obvious answer is the atmosphere. That's also the premise of carbon sequestration. The problem is that CO2 isn't actually particularly abundant. It's currently hovering around 400 parts per million - that's about 0.04% of air. To make a kg of hydrocarbon you need to process an awful lot of air to get enough CO2. That all takes energy. A lot of energy. Suddenly your round trip efficiency is practically zero. If these guys have cracked that problem, it would be fantastic. I hope they have, but I suspect they haven't.
- thereisnospork 7y ago
  There are lots of point sources of CO2 that don't require as much energy to extract, but your point stands: the conversion takes a lot of energy (thermodynamics is a harsh mistress). The tech works quite well though, CRI in Iceland makes methanol (a viable liquid fuel) from CO2 and electrolyzed H2 semi-commercially, taking advantage of cheap and abundant geomthermal electricity.
- thisisbrians 7y ago
  I came here to say essentially this. To your point about how low (in percentage terms) the concentration of CO2 is, direct carbon capture from the atmosphere still seems a fool's errand to me. The only way I see carbon capture being at all viable for this purpose in the short term is to scrub the waste gasses from industrial processes where carbon-containing compounds are extremely concentrated.
  - tim333 7y ago
    The green beaches thing seemed quite promising https://news.ycombinator.com/item?id=20403570 https://news.ycombinator.com/item?id=20403570
nradov 7y ago
The US Navy is already experimenting with producing synthetic jet fuel on aircraft carriers using power from the nuclear reactor. Their concern is with reducing the logistics chain rather than environmentalism. But if the research results are made public they could be applied to commercial aviation.
- DuskStar 7y ago
  It would be really interesting to see that getting applied to a fleet oiler design. A nuclear powered tanker that constantly refills itself for the DDs and CGs to use...
bassman9000 7y ago
"It sure does sound amazing. It sounds like a solution to all of our problems - except that it's not," said Jorien de Lege from Friends of the Earth. "If you think about it, this demonstration plant can produce a thousand litres a day based on renewable energy. That's about five minutes of flying in a Boeing 747. This is the same people that have faith in that technology in renewables can improve to one day surpass nuclear.
eternalny1 7y ago
I envision a future (not too far away) where we can literally turn anything into anything else reasonably efficiently. CO2 in the atmosphere with hydrogen and oxygen from water, waste into each of its base component atoms, whatever into whatever else. Something like global recycling of everything, if that makes any sense.
tito 7y ago
On Saturday, Elon Musk said that SpaceX will use direct air capture to make fuel from air on Earth: https://youtu.be/sOpMrVnjYeY?t=3852 https://youtu.be/sOpMrVnjYeY?t=3852 In partnership with Climeworks, one of the leading DAC companies, I just launched a campaign on Kickstarter using carbon materials to make a bracelet made of captured atmospheric carbon dioxide. Check out the video! https://www.kickstarter.com/projects/go-negative/negative-bracelet-captured-carbon-dioxide https://www.kickstarter.com/projects/go-negative/negative-br...
jbaumg 7y ago
I am involved in this project. The aim is to built a demonstration plant to show the feasibility of the process and to develop a blueprint for larger plants that can produce sustainable jet fuel economically. Producing sustainable fuels is always more expensive than fossil fuels. However, upcoming legislation and taxation (at least in the EU) will change this equation. Someone mentioned an efficiency of around 50% in a post here and resulting pricing, that's a fairly good estimate of the overall process and what is discussed as achievable cost for renewable synthetic fuels in general. The process is in this demonstration plant is Fischer-Tropsch. Using CO2 from an industrial point source is more efficient; however, it has potential legislative issues when it comes to certification of sustainable fuels, emission certificate trading... it's a fairly complicated topic. In addition, worldwide potential for lowest renewable energy costs does not correlate necessarily with existing CO2 point sources. That's why direct air capture makes a lot of sense. Whether CCS is a better solution depends on renewable electricity pricing vs. the CCS costs, public acceptance and feasibility at the location of a plant. These vary strongly depending on where you are in the world. In many parts of Europe there is strong opposition to it as it may prolong the exploitation of fossil sources.
- mogadsheu 7y ago
  Finally, an expert! I’m not, although I’ve been involved in energy for a while now. I believe the Germans made synfuels towards the end of WWII using Fischer Tropsch when they were running low on conventional fuels. What tech is new about this project, besides the energy source?
  - jsilence 7y ago
    Two decades and some ago a german company named Choren also produced SunDiesel in a similar process. They shut down this line of work quite some time ago. Not feasible.
  - dredmorbius 7y ago
    Germany, during WWII, and South Africa's SASOL since the 1970s: https://www.netl.doe.gov/research/Coal/energy-systems/gasification/gasifipedia/sasol https://www.netl.doe.gov/research/Coal/energy-systems/gasifi...
credit_guy 7y ago
So, here's how to kill a few birds with one rock. Make jet fuel using nuclear energy. But nuclear energy is horribly expensive, right? No, civilian nuclear energy is horribly expensive. The US Navy churns out nuclear reactors at a steady pace, and operate them perfectly safely. They've never had any incident. If the Congress mandates the US Navy to become net zero carbon emitter, they can do it. And they also gain additional logistical simplification. They say that every gallon of fuel sent to the front line in Iraq costs the DoD $100. Yes, in the oil-soaked Iraq. If you shorten the supply line, maybe this price goes down to a more reasonable level. Can you imagine that, instead of getting a war for the exorbitant price of $10 trillion, you can get one for a paltry $1 trillion? We could get 10 wars for the price of one.
- cameronbrown 7y ago
  > They've never had any incident. I'm not being conspiratorial here, but if there was an incident, which would make the navy look vulnerable and weak to both the population and potential enemies, would we ever know about it?
  - maxerickson 7y ago
    A big chunk of incidents would be known to adversaries just by their nature.
mastazi 7y ago
> "It'd be a mistake to think that we can keep flying the way that we do because we can fly on air. That's never going to happen. It's always going to be a niche". Why did BBC include such a strong statement in the article, given that it's just someone's gratuitous personal opinion? I know that it's good journalistic practice to include sceptical opinions, but couldn't they find someone who is sceptical while at the same time being able to back their opinion with some sort of evidence or arguments? Edit: it's also possible that this person's contribution was a longer text, and that it was cut short due to the article length limits. Maybe the original text included better arguments? It would be unfortunate if that was the case.
perfunctory 7y ago
Whatever happened to Prometheus? I haven't heard anything since their launch [0]. The website doesn't have any updates [1]. Complete radio silence. [0] https://news.ycombinator.com/item?id=19842240 https://news.ycombinator.com/item?id=19842240 [1] https://www.prometheusfuels.com/ https://www.prometheusfuels.com/
perfunctory 7y ago
In the synthetic fuel world, how much renewable energy capacity would we need globally? We need to replace all current electricity generation with renewables, then we need to add more to power electric cars, and then some more to produce synfuel. That sounds like a lot of capacity.
teekert 7y ago
"It sure does sound amazing. It sounds like a solution to all of our problems - except that it's not," said Jorien de Lege from Friends of the Earth. "If you think about it, this demonstration plant can produce a thousand litres a day based on renewable energy. That's about five minutes of flying in a Boeing 747. "It'd be a mistake to think that we can keep flying the way that we do because we can fly on air. That's never going to happen. It's always going to be a niche." Wow, the Naysayers really know how to build a constructive argument.
Swivekth18 7y ago
"This demonstration plant can produce a thousand litres a day based on renewable energy. That's about five minutes of flying in a Boeing 747"

97 points by theklub 7y ago

rpmisms 7y ago

Why not just process biomass?

SketchySeaBeast 7y ago
The article says those are costly, and the cost would have to be passed onto the consumer. Honestly this feels like it's a feel-good piece "look, we're doing our part!" when the technology is still a long ways away. Better than saying that the airlines are working on teleportation, but I don't know by how much.
dredmorbius 7y ago
There isn't enough. Even for aviation alone, which is about 6% of US fossil fuel consumption, using a process Boeing had lauded as a "breakthrough" a few years ago, essentially using a salt-water pickleweed (halophytes), you'd need the entire states of Kansas and Oklahoma, plus considerable chunks of Nebraska and surrounding states, to meet present US demand. We use a lot of fossil fuels. Mind-boggling amounts. And those accumulated slowly over immensely long periods of time, though that's due to inefficiencies both in what ancient biomass was kerogenised in the first place, and the losses in keroginisation (essentially: petroleum formation). Jeffrey S. Dukes, "Burning Buried Sunshine" (2003), lays this out for coal, oil, and gas. For petroleum, we're presently burning about 5 million years of accumulated fossil biomass every year. Or, alternatively, we burn through a full ancient year's biomass accumulation every 6.3 seconds. All biomass, roughly, equates all human and livestock feed, plus some construction materials waste-streams (mostly wood and forestry products). When you say "use biomass", you're really saying "go through the leftovers of humans and livestock". And quite simply, there's not all that much there. Maybe 5-10% of current total energy use if you could efficiently capture the entire wastestream (and keep in mind that it is very widely distributed. In practice, you could probably power waste water treatment plants off of captured biomass, with some surplus left over. But not much more than that.

tedmcory77 7y ago

Sounds very similar to Prometheus Fuels. The AMA thread on here from the founder was amazing.

detritus 7y ago
To save anyone else curious the hardship of searching... https://news.ycombinator.com/item?id=19842240 https://news.ycombinator.com/item?id=19842240

tengbretson 7y ago

Sounds like some kind of Fischer–Tropsch process. Starting with CO2 sounds like it would require an obscene amount of electricity though.

Analemma_ 7y ago
> Starting with CO2 sounds like it would require an obscene amount of electricity though. It could still be worth it, depending on how/when it was made and how it interacted with the grid. There's an increasing problem right now of too much solar supply during the day and not enough power storage; projects like this could be used to soak up excess power and it would still come out carbon-neutral.
- MrBuddyCasino 7y ago
  Germany is paying other countries to absorb spikes. Anything that creates value instead looks like a win to me.

comnetxr 7y ago

The question should not be whether this is too costly as compared to jet fuel, but at what carbon price is it cheaper than jet fuel? Once the cost of carbon is at the long term limit, which is equal to the cost of extracting carbon from the atmosphere, then these technologies could be much more cost effective. (But if they aren't, there would be no reason to ban flying, as the carbon price would pay for the extraction of carbon that flying produces.) By not account for how much jet fuel costs with increasing carbon pricing, and by framing the alternative to allowing climate change as banning flying, it seems like the author has completely missed the story..

ajross 7y ago

This always strikes me as missing the point. The end result is fuel to burn. It doesn't matter where it comes from, only what the net carbon budget is. Continuing to burn petroleum in jet engines is fine, as long as it's appropriately offset. There's absolutely no technical reason to need to bend over to implement this kind of setup. Spend those dollars on renewables and sequestering solutions instead, clean up the last 10% of fossil fuel extraction at the end of the process.

quickthrower2 7y ago
Lots of people working on different ideas to help reduce CO2 is probably what we need though. We don't know what will be the 'winner' yet, but the more things we try the more likely we are to find the best solution(s).
dredmorbius 7y ago
Good fuels are hard to find. The problems with petroleum (and natural gas) are twofold. One is the carbon emissions, but the other is the fact that supplies will eventually run out, and have to be substituted by something. And as we try to pursue every last fraction of petroleum, the environmental costs will rise -- increasingly hard-to-access, high-risk, or heavy-treatment options. Think deep water, Deepwater Horizons, and tar sands and fracking. Hydrocarbons are great fuels, and for some applications, especially powered flight, there's virtually no other viable alternative. Keep in mind that the aeroplane and automobile both appeared at virtually the same moment -- the principle requirements for each were high power-to-weight engines and energy-dense fuels. Sorting out the mechanical and aeronautical problems were relatively straightforward. (Lightweight sturctural aluminium also helped markedly, and also became available largely through the same related set of technological processes providing Otto-cycle engines and petrol-based fuels.)

nickcw 7y ago

Let me get out my back of the envelope for some quick and inaccurate calculations ;-) There are 10.3 kWh of energy in a litre of Jet A1 fuel. Let's assume (generously I think) that the process is about 50% efficient, so it takes ~20 kWh of electricity to make a litre of Jet fuel. Assuming (amortized) solar power is the same cost as grid power ~$0.1/kWh then to make your litre of fuel costs 20 *0.2 = ~$2/litre According to my research Jet A1 costs about ~$0.50/litre. So this is a way off at the moment, however if there was tax on fossil fuels for aviation then this could be competitive.

markvdb 7y ago
Depending on how capital intensive the plant is, this might still be cost competitive with intermittent low, zero or negatively priced green electricity.
- jblow 7y ago
  Also ... renewables are always going through cycles of high and low availability. Prices vary across these cycles. If you make your fuel only at the time during the day when there is the highest delta between supply and demand, then you pay the minimum electricity cost, and the utilities are glad to have you there to balance the load.
  - ThrustVectoring 7y ago
    Note that this economic strategy is already in place in other industries where electricity price is a large component of the final cost of goods sold. Aluminum smelting is a huge example of this.
- happosai 7y ago
  Large-scale Negative, zero or below-cost renewables only happen if someone else foots the bill. And that usually means tax-payer funded subsidies. I mean sure, there will be some hours during exceptionally sunny/windy days when price is less than the production cost, but don't bet your business on it. What does work is building the plant in a wind/solar abudant location and co-siting with large, behind-the-meter wind/solar plant. Not only do you get electricity at cost, but you cut the grid costs and taxes away too.

vilhelm_s 7y ago

I guess a more low-tech approach would be to fuel jets with ethanol. Googling a bit now, the U.S. uses about 18 billion gallons/year of jet fuel[1], and produces 17 billion gallons/year of fuel ethanol [2]. The price per gallon is about $1.5 versus $1.94 [3,4]; because jet fuel has 46% higher energy density that means that the cost per Joule would increase by a factor of 1.9. Obviously this is only a back-of-the-envelope thing, but it seems that even if we switched to renewable fuels using the technology that are available today, ticket prices should about double. Historically, that corresponds to going back to circa-1980 prices[6], which I guess is bad, but not exactly apocalyptic. [1] https://www.eia.gov/todayinenergy/detail.php?id=31512 https://www.eia.gov/todayinenergy/detail.php?id=31512 [2] https://www.eia.gov/todayinenergy/detail.php?id=32152 https://www.eia.gov/todayinenergy/detail.php?id=32152 [3] https://markets.businessinsider.com/commodities/ethanol-price https://markets.businessinsider.com/commodities/ethanol-pric... [4] https://www.indexmundi.com/commodities/?commodity=jet-fuel https://www.indexmundi.com/commodities/?commodity=jet-fuel [5] https://en.wikipedia.org/wiki/Energy_density https://en.wikipedia.org/wiki/Energy_density [6] https://www.theatlantic.com/business/archive/2013/02/how-airline-ticket-prices-fell-50-in-30-years-and-why-nobody-noticed/273506/ https://www.theatlantic.com/business/archive/2013/02/how-air...

ulfw 7y ago
You answered your own question. " jet fuel has 46% higher energy density" That's why. Few things matter more when lifting things into the air than weight.
- vilhelm_s 7y ago
  I guess the current long routes would not work, but apparently airliner fuel efficiency improved by almost exactly this much since 1980 (https://www.greenaironline.com/news.php?viewStory=684 https://www.greenaironline.com/news.php?viewStory=684), so it still seems that's the era we'd go back to...
throw_into_air 7y ago
The problem with ethanol is it absorbs water, which at greater altitudes (lower temperature and pressure) freezes and blocks fuel lines. For that reason aviation fuels have limits on ethanol content.

leoedin 7y ago

The jet fuel part of this is a distraction from the important (and hard) part - turning electricity into usable liquid fuel. Electrolysis is easy enough, and there's plenty of places with enough water. Then you have hydrogen. Hydrogen is not nice to work with, store or use, so you want to turn it into something else a bit nicer. The problem is, almost all practically usable liquid or gaseous fuels contain carbon. Where do you get that from? The obvious answer is the atmosphere. That's also the premise of carbon sequestration. The problem is that CO2 isn't actually particularly abundant. It's currently hovering around 400 parts per million - that's about 0.04% of air. To make a kg of hydrocarbon you need to process an awful lot of air to get enough CO2. That all takes energy. A lot of energy. Suddenly your round trip efficiency is practically zero. If these guys have cracked that problem, it would be fantastic. I hope they have, but I suspect they haven't.

thereisnospork 7y ago
There are lots of point sources of CO2 that don't require as much energy to extract, but your point stands: the conversion takes a lot of energy (thermodynamics is a harsh mistress). The tech works quite well though, CRI in Iceland makes methanol (a viable liquid fuel) from CO2 and electrolyzed H2 semi-commercially, taking advantage of cheap and abundant geomthermal electricity.
thisisbrians 7y ago
I came here to say essentially this. To your point about how low (in percentage terms) the concentration of CO2 is, direct carbon capture from the atmosphere still seems a fool's errand to me. The only way I see carbon capture being at all viable for this purpose in the short term is to scrub the waste gasses from industrial processes where carbon-containing compounds are extremely concentrated.
- tim333 7y ago
  The green beaches thing seemed quite promising https://news.ycombinator.com/item?id=20403570 https://news.ycombinator.com/item?id=20403570

nradov 7y ago

The US Navy is already experimenting with producing synthetic jet fuel on aircraft carriers using power from the nuclear reactor. Their concern is with reducing the logistics chain rather than environmentalism. But if the research results are made public they could be applied to commercial aviation.

DuskStar 7y ago
It would be really interesting to see that getting applied to a fleet oiler design. A nuclear powered tanker that constantly refills itself for the DDs and CGs to use...

bassman9000 7y ago

"It sure does sound amazing. It sounds like a solution to all of our problems - except that it's not," said Jorien de Lege from Friends of the Earth. "If you think about it, this demonstration plant can produce a thousand litres a day based on renewable energy. That's about five minutes of flying in a Boeing 747. This is the same people that have faith in that technology in renewables can improve to one day surpass nuclear.

eternalny1 7y ago

I envision a future (not too far away) where we can literally turn anything into anything else reasonably efficiently. CO2 in the atmosphere with hydrogen and oxygen from water, waste into each of its base component atoms, whatever into whatever else. Something like global recycling of everything, if that makes any sense.

tito 7y ago

On Saturday, Elon Musk said that SpaceX will use direct air capture to make fuel from air on Earth: https://youtu.be/sOpMrVnjYeY?t=3852 https://youtu.be/sOpMrVnjYeY?t=3852 In partnership with Climeworks, one of the leading DAC companies, I just launched a campaign on Kickstarter using carbon materials to make a bracelet made of captured atmospheric carbon dioxide. Check out the video! https://www.kickstarter.com/projects/go-negative/negative-bracelet-captured-carbon-dioxide https://www.kickstarter.com/projects/go-negative/negative-br...

jbaumg 7y ago

I am involved in this project. The aim is to built a demonstration plant to show the feasibility of the process and to develop a blueprint for larger plants that can produce sustainable jet fuel economically. Producing sustainable fuels is always more expensive than fossil fuels. However, upcoming legislation and taxation (at least in the EU) will change this equation. Someone mentioned an efficiency of around 50% in a post here and resulting pricing, that's a fairly good estimate of the overall process and what is discussed as achievable cost for renewable synthetic fuels in general. The process is in this demonstration plant is Fischer-Tropsch. Using CO2 from an industrial point source is more efficient; however, it has potential legislative issues when it comes to certification of sustainable fuels, emission certificate trading... it's a fairly complicated topic. In addition, worldwide potential for lowest renewable energy costs does not correlate necessarily with existing CO2 point sources. That's why direct air capture makes a lot of sense. Whether CCS is a better solution depends on renewable electricity pricing vs. the CCS costs, public acceptance and feasibility at the location of a plant. These vary strongly depending on where you are in the world. In many parts of Europe there is strong opposition to it as it may prolong the exploitation of fossil sources.

mogadsheu 7y ago
Finally, an expert! I’m not, although I’ve been involved in energy for a while now. I believe the Germans made synfuels towards the end of WWII using Fischer Tropsch when they were running low on conventional fuels. What tech is new about this project, besides the energy source?
- jsilence 7y ago
  Two decades and some ago a german company named Choren also produced SunDiesel in a similar process. They shut down this line of work quite some time ago. Not feasible.
- dredmorbius 7y ago
  Germany, during WWII, and South Africa's SASOL since the 1970s: https://www.netl.doe.gov/research/Coal/energy-systems/gasification/gasifipedia/sasol https://www.netl.doe.gov/research/Coal/energy-systems/gasifi...

credit_guy 7y ago

So, here's how to kill a few birds with one rock. Make jet fuel using nuclear energy. But nuclear energy is horribly expensive, right? No, civilian nuclear energy is horribly expensive. The US Navy churns out nuclear reactors at a steady pace, and operate them perfectly safely. They've never had any incident. If the Congress mandates the US Navy to become net zero carbon emitter, they can do it. And they also gain additional logistical simplification. They say that every gallon of fuel sent to the front line in Iraq costs the DoD $100. Yes, in the oil-soaked Iraq. If you shorten the supply line, maybe this price goes down to a more reasonable level. Can you imagine that, instead of getting a war for the exorbitant price of $10 trillion, you can get one for a paltry $1 trillion? We could get 10 wars for the price of one.

cameronbrown 7y ago
> They've never had any incident. I'm not being conspiratorial here, but if there was an incident, which would make the navy look vulnerable and weak to both the population and potential enemies, would we ever know about it?
- maxerickson 7y ago
  A big chunk of incidents would be known to adversaries just by their nature.

mastazi 7y ago

> "It'd be a mistake to think that we can keep flying the way that we do because we can fly on air. That's never going to happen. It's always going to be a niche". Why did BBC include such a strong statement in the article, given that it's just someone's gratuitous personal opinion? I know that it's good journalistic practice to include sceptical opinions, but couldn't they find someone who is sceptical while at the same time being able to back their opinion with some sort of evidence or arguments? Edit: it's also possible that this person's contribution was a longer text, and that it was cut short due to the article length limits. Maybe the original text included better arguments? It would be unfortunate if that was the case.

perfunctory 7y ago

Whatever happened to Prometheus? I haven't heard anything since their launch [0]. The website doesn't have any updates [1]. Complete radio silence. [0] https://news.ycombinator.com/item?id=19842240 https://news.ycombinator.com/item?id=19842240 [1] https://www.prometheusfuels.com/ https://www.prometheusfuels.com/

perfunctory 7y ago

In the synthetic fuel world, how much renewable energy capacity would we need globally? We need to replace all current electricity generation with renewables, then we need to add more to power electric cars, and then some more to produce synfuel. That sounds like a lot of capacity.

teekert 7y ago

"It sure does sound amazing. It sounds like a solution to all of our problems - except that it's not," said Jorien de Lege from Friends of the Earth. "If you think about it, this demonstration plant can produce a thousand litres a day based on renewable energy. That's about five minutes of flying in a Boeing 747. "It'd be a mistake to think that we can keep flying the way that we do because we can fly on air. That's never going to happen. It's always going to be a niche." Wow, the Naysayers really know how to build a constructive argument.

Swivekth18 7y ago

"This demonstration plant can produce a thousand litres a day based on renewable energy. That's about five minutes of flying in a Boeing 747"