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Could Carbon Dioxide Be Turned into Jet Fuel?
- mcherm 6y agoThe article says that by adding heat to raw materials such as carbon dioxide and some catalyst they can produce jet fuel. Which can be burned to produce carbon dioxide and more heat. I'm glad to know that according to this article's author they have invented a perpetual motion machine that generates free energy. I would however, prefer to read an article by someone who understands basic thermodynamics and feels like explaining this to an audience who is assumed to also understand basic thermodynamics. Presumably there is an input of energy (other than heat) which is the most significant part of generating jet fuel -- but unless I overlooked something, the article doesn't mention it.
- philipwhiuk2 6y agoWhy does there need to be energy other than heat if the heat is enough and it's endothermic?
- aaronblohowiak 6y agoIt is using the fuel as a battery. Will still take more energy in than you get by burning, but it is better to do that from solar than digging it out of the ground
- hertzrat 6y agoSimple question: will it take less energy to do the conversion than you get out the other end? Will the process itself generate less carbon than the existing process? All these “net zero” claims never mention how the rest of the system is affected. Eg, zero emission electric cars: where I live, our electricity comes from coal power plants.
- danielheath 6y agoObviously not (laws of thermodynamics), but if we ever get eg a profitable fusion reactor going, it'll be a huge deal to be able to do this - because existing petroleum-fuel stock will still need to run.
- jeffbee 6y agoWe already enjoy the services of a massive optically-coupled fusion energy source. All we need to do it plug it in.
- nradov 6y agoIf fusion power ever works it could be a useful base load source to replace coal and fission. But fusion is unlikely to ever be cost competitive with solar and wind, so I expect those sources to be used for synthesizing liquid fuel.
- tempestn 6y agoAgreed; this kind of thing seems like a more attractive target for unused peak capacity of renewables. But it only makes sense if the capital costs are low enough that the economics still work even if it's only run part time. Which is a pretty high bar.
- carbonguy 6y agoTaking your questions in turn: 1) The conversion will always be energy-negative due to the laws of thermodynamics, as a sibling comment mentioned. This is true even of existing fossil fuels, though we tend not to think of it that way. 2) The process of converting CO2 to hydrocarbon fuels leads to a decrease in atmospheric carbon. Burning these fuels or fossil fuels (what I assume you mean by "the existing process") produces an increase in atmospheric carbon. This means it's possible to create a net-positive, net-neutral, or net-negative outcome with respect to atmospheric CO2 concentration depending on how you balance these two processes. As you point out, "zero emission" doesn't mean the same thing as "no net CO2 release"; rather, it more often means "zero emissions of CO2 at the point of energy usage," with CO2 emissions usually occurring elsewhere. That said, with a system of hydrocarbon fuel production from air-captured CO2 it is genuinely possible to have "zero emission" mean "zero net emission of CO2 over the entire energy transport process." EDIT: The key enabling technology is, of course, carbon-free renewable energy, of which solar is likely to represent the lions' share as time passes.
- seltzered_ 6y agoActual nature article linked within wired post: https://www.nature.com/articles/s41467-020-20214-z https://www.nature.com/articles/s41467-020-20214-z Last one in the e-fuel space I was staring at was: https://doi.org/10.1016/j.joule.2020.01.002 https://doi.org/10.1016/j.joule.2020.01.002 from Rob McGinnis of a startup called Prometheus. airminers.org lists other startups in this space. I'm still skeptical of it but curious to see what's out there.
- wrycoder 6y agoOf course it can. If we have a large supply of very cheap energy, say from fusion or feeding a black hole, then a CO2 to jet fuel to CO2 cycle can be considered the same kind of thing as charging and discharging a battery. And it would be similarly "net zero" for CO2.
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- acidburnNSA 6y agoExactly. It's not "making fuel" in the sense that would be energy positive. It's using CO₂ as feedstock into an energy conversion process that transforms energy otherwise obtained into a form usable in jet engines. I hope these misleading "turned into" style of headlines go away when energy input is required. Carbon + Hydrogen + Oxygen + energy + information can be "turned into" pretty much any organic substance.
- Hypx 6y agoWe already have that in the form of fission. The problem is our societal lack of interest in fission.
- worldsayshi 6y agoEven if we had access to free electricity, wouldn't it still be cheaper to utilize existing petroleum infrastructure? I mean, until the reserves are depleted the energy is basically free, we just need to pump it up and refine it. (Then again, solar power is basically "free", we just need to catch it and store it... so my 2nd paragraph is maybe kind of dumb.)
- wffurr 6y agoI think Carbon Engineering already has a pilot plant making gasoline: https://carbonengineering.com/our-technology/ https://carbonengineering.com/our-technology/ The example in the article of colocating with a coal plant is bonkers. Seems like coal gasification would be more efficient than turning coal into electricity and carbon and then trying to turn the carbon into liquid fuels. This is a valuable technique but only if we have a lot of spare clean electrical power to do it with.
- philipwhiuk2 6y agoAlternatively, methane is easier to create from Carbon Dioxide. Burning methane in an engine is practical. https://climate.miami.edu/renewable-energy/methane-as-a-fuel-source/ https://climate.miami.edu/renewable-energy/methane-as-a-fuel...
- s0rce 6y agoMethane doesn't seem very practical for an airplane, storing the pressurized gas in tanks seems heavy. Would you store liquid methane? Liquid methane and liquid oxygen are used as rocket propellants, not sure if that makes sense for an airplane compared to conventional liquid (at ambient temperature/pressure) fuels.
- carbonguy 6y agoYou're correct: methane would not work well as a replacement for conventional aviation fuel both for the reason you mention (weight of storage system) as well as the lower energy density per unit volume: 35 MJ/L for jet fuel vs. 9 MJ/L for compressed natural gas at 3600 PSI. (https://en.wikipedia.org/wiki/Energy_density https://en.wikipedia.org/wiki/Energy_density)
- aaronblohowiak 6y agoI think LNG would be more likely candidate , and doesn’t kg matter more than L here?
- sokoloff 6y agokg matters a lot, of course, but most airplanes are out of space for additional tankage as currently designed. (They are designed for a given mount of fuel capacity volume, in relation to the mass of that fuel volume. None would have a 4x multiple.) Scaling volumetric storage by a factor of four produces about 2.5x the wetted frontal area (4 ^ (2/3))
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- exabrial 6y agoI'd rather CO2 be turned into a building material... like wood or bricks. That way it's fixated. Sorta defeats the purpose to put it back out into the atmosphere, and why I don't really see today's "carbon capture" stuff going anywhere unless we find a source of "free" energy.
- sokoloff 6y agoIt depends on your comparison point. If the comparison point is "we're going to fly all these airplanes; with what shall we fuel them?" it makes a lot more sense than if you start with "we have a lot of excess energy and want to remove carbon dioxide from the atmosphere; where shall we put it?"
- exabrial 6y agoAh so what you're saying is it's like flying an airplane with a nuclear plant, but the nuclear plant is on the ground and hooked up to a hydrocarbon plant as an intermediary.
- Animats 6y agoIt's called "wood". Trees are 90-95% air. Carbon, hydrogen, oxygen, nitrogen. Here's Feynman explaining this.[1] [1] https://youtu.be/ITpDrdtGAmo https://youtu.be/ITpDrdtGAmo
- exabrial 6y agoThis new fangled technology is incredible. I visited one of these "tree stores" and I do admit the smell of the tree section was quite pleasing.
- imtringued 6y agoHow do you capture CO2 from a jet? Do you store it onboard? Direct air capture seems incredibly inefficient.
- sokoloff 6y agoYou don't. You take yesterday's CO2 from the atmosphere, turn it into today's fuel, and emit it as tomorrow's CO2 into the atmosphere. Then repeat the cycle continuously. If you were successful in capturing the CO2 from the jet and taking it to the point of landing, the airplane would get (much!) heavier as it flew rather than lighter.
- carbonguy 6y agoThe advance described in the paper in question could turn out to have a fairly significant impact on the economics of an air-to-fuels process that includes it. For context: the paper describes an air-to-fuels system requires carbon dioxide as a carbon source as well as some source of hydrogen gas. Given these two feedstocks there are then two main routes to fuel production: reduction of carbon dioxide to methanol or ethanol, which can then be "upgraded" to heavier fuels, or reduction of carbon dioxide to carbon monoxide, which is used along with the hydrogen to feed a Fischer-Tropsch reaction producing a variety of fuels directly. My understanding is that in either case production costs are dominated by the cost of acquiring the feedstocks, which are in turn mainly driven by the cost of energy. What the article describes is a technique that modifies the Fischer-Tropsch step of the process that uses it, which would perhaps bring costs down somewhat for that step. Additionally, and more importantly, carbon monoxide is not needed as a separate feedstock as CO2 is apparently directly reduced by this new catalyst - this is where significant cost savings could potentially realized. I'm no expert in any of this but for what it's worth I did go through a process of estimating what "air-to-fuels" fuel might cost to produce and came up with a cost of about $1300 per metric ton. If the technique described in the paper were applied to the process I investigated, the $1300/mt price could potentially decrease to around $1000/mt. For comparison, Brent crude oil is currently about $380/mt and aviation fuel is about $430/mt. [EDIT] Forgot to include a link to my analysis: https://bit.ly/34JTCFm https://bit.ly/34JTCFm
- idlewords 6y agoWhere does wired think regular jet fuel came from in the first place?
- tito 6y agoIf you want to work on how to do this rather than "could", come join AirMiners...kind of like HN for carbon removal. http://airminers.org http://airminers.org
- adrianN 6y agoYou need to fix your certificates.
- rich_sasha 6y agoNow if we replaced proof of work in Blockchains with “proof of CO2 conversion”...