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Chemists create methane fuel from sun, carbon dioxide and water (2022)
- forgetfreeman 4y agoGiven methane is a significantly more aggressive greenhouse gas than CO2 one questions the wisdom of this approach. Ah well, pure research I guess.
- malfist 4y agoIt is a stronger greenhouse gas than CO2, but it doesn't last as long in the atmosphere. Probably not good short term solution.
- andsoitis 4y ago… than other artificial systems, not that in nature.
- armada651 4y ago> “The biggest challenge many people don’t realize is that even nature has no solution for the amount of energy we use,” said University of Chicago chemist Wenbin Lin. Not even photosynthesis is that good, he said: “We will have to do better than nature, and that’s scary.” Aren't solar panels already more efficient at creating energy than photosynthesis? It's true we haven't found an artificial method of photosynthesis that creates a fuel we can burn that is more efficient than nature, but do we want to?
- koverda 4y agoWe can just store the fuel for carbon capture in that case, right?
- armada651 4y agoSure, but if carbon capture is the goal there are easier methods than artificial photosynthesis. The point of artificial photosynthesis is to create a fuel you can eventually burn again. Re-using the CO2 in the atmosphere certainly beats simply adding to it, I'm guessing that's the point here.
- tinco 4y agoFor it to be truly sustainable the carbon needs to be stored in a way that humans wouldn't get at out of greed ever again. So it would need to be in some useless form like maybe diamonds or something. A ton of CO2 is produced by about $150 worth of fuel (oil). So if you can do carbon capture for less than $150/tCO2 it would make more sense to sell the fuel and capture more carbon.
- nomel 4y ago> So if you can do carbon capture for less than $150/tCO2 it would make more sense to sell the fuel and capture more carbon. How does this math work? If it's $149 to recapture, who's paying for this $149? Is the person buying $150 worth of fuel now paying for it also, at ($150 + recapture cost)/gallon?
- blackoil 4y agoI believe the idea is to sell captured carbon to be used as fuel. So we are net 0.
- aziaziazi 4y agoThat would be valid once we stop extracting carbons from other sources (oil, gaz, coil…). Since that won’t happen at a global scale soon, burning the captured carbon won’t stop the carbonification of the air/water.
- tinco 4y agoThe $1 profit goes towards paying for capturing carbon. Every 150 barrels of captured fuel you sell, you make $75 profit you could spend on either not selling a barrel, or some more efficient way of reducing our climate impact like maybe buying a solar panel or sponsoring a windmill. Or what the sibling suggests, you keep the money as profit / funds for growing the business so you displace traditional oil and you prevent the increase of CO2 in the atmosphere that way.
- nephanth 4y agoIn terms of energy, you'll always need more to recapture than burning that fuel will give you (cuz entropy) So if money = energy (which is a wrong assumption), buying that barrel would always be a loss
- taneq 4y agoExactly. Our best ornithopters still aren't as good as birds and probably will never be. I guess air travel is doomed.
- csours 4y ago> Aren't solar panels already more efficient at creating energy than photosynthesis? Solar panels convert light to electricity. Photosynthesis uses light to rebuild molecules into sugars. Plants are about 1-2% efficient - https://en.wikipedia.org/wiki/Photosynthetic_efficiency https://en.wikipedia.org/wiki/Photosynthetic_efficiency Modern solar cells easily hit 20% efficiency under decent conditions. > It's true we haven't found an artificial method of photosynthesis that creates a fuel we can burn that is more efficient than nature, but do we want to? If we want to use airplanes to quickly travel long distances, yes. Or if we want to haul loads to many arbitrary locations.
- senttoschool 4y agoPhotosynthesis covers the vast majority of land and ocean available on Earth while solar panels cover far less. So in a way, photosynthesis is more efficient - in a scalable way.
- XorNot 4y agoYeah but that's a function of self-replication. If you could engineer a tuber or vine which did nothing but try to build up a huge H+ ion gradient between it's roots and it's tip, then we could just let that grow indefinitely and use it as a battery directly. Similarly most models of "grey goo" would functionally be this: machines autonomously covering the biosphere in more efficient light harvesters.
- andreareina 4y agoThat's not how you measure efficiency
- senttoschool 4y agoHow do you measure efficiency?
- dymk 4y agoPer unit area or volume or mass
- maxerickson 4y agoI'm not sure what they mean anyway. The amount of solar energy hitting earth is a lot larger than human energy utilization. Like by a factor of 10000 (tens of terawatts vs ~100 petawatts).
- lm28469 4y agoWell first of you'd have to reduce that by the efficiency of our panels, so we're down to 20 petawatts And then you'd have to factor in the fact that basically none of the planet can be covered in solar panels And then the fact that you wouldn't be able to efficiently transport the energy to where we need it So yes in theory you put a couple hundred sqkm of solar panels in the Sahara and you're golden, in practice it's much more complex
- sacred_numbers 4y agoWe have, but it's not a single process. We can convert light to electricity quite cheaply and efficiently with solar PV panels and then use that electricity to electrolyze hydrogen from water and capture CO2 from air(or seawater). Then there are a variety of processes, such as the Sabatier reaction, to convert the hydrogen and carbon into a hydrocarbon. I believe Prometheus Fuels is combining the hydrogen electrolysis and CO2 capture into a single step. Terraform Industries is also working on this problem, but is focused on driving down capital costs of electrolysis so that carbon neutral fuel producers can afford to have electrolyzers sitting around unused 75% of the year and only working when solar electricity is so abundant that it's practically free. Electrolysis and carbon capture takes a lot of energy, but assuming that all electricity comes from solar panels, it is far more space efficient than biofuels. An acre of corn or sugarcane can produce about 400-700 gallons of ethanol per year, or about 36-64 gigajoules of fuel. An acre of solar panels (laid nearly flat to maximize space efficiency) that is converted to methane at 30% efficiency (efficiencies around 50-60% are very normal and state of the art is around 75%, but 30% is much easier and cheaper) can produce about 350 gigajoules of fuel per year. There's also some research on converting hydrogen and CO2 to edible carbohydrates, either chemically or through hydrogenotrophic or methanotrophic bacteria. That will be a huge revolution for either increasing the carrying capacity of the planet or decreasing humanity's impact on the planet. It will also be a huge boon for countries without much arable land to be able to feed their people without relying on imports. Electricity to food is not quite ready for scaling up yet, but synthetic fuels are absolutely ready to go as soon as solar electricity prices drop just a bit more or fossil fuel prices rise a bit more.
- G3rn0ti 4y ago> We have, but it's not a > single process. Technically, biological photosynthesis consists of two different major processes. You’ve got a membrane complex called „photosystem“ (of which they are two types) and an enzyme called Rubisco. The former drives the light reactions oxidizing water into hydrogen and oxygen (and thereby creating reducing agents and a proton gradient). The latter drives the dark reactions reducing CO2 into various forms of sugar. In some plants CO2 fixation runs at night and, hence, at a different time than the light reactions. In others, it happens in different cells and, hence, physically separated from the light reactions. CAM and C4 plants, respectively, are more efficient in hot or dry biotopes.
- Guthur 4y agoIts a ridiculous statement. Nature, if that's what you want to call it has to all intents and purposes infinite energy. Our ability to release energy from matter is what we have built upon.
- elromulous 4y agoDirect link[0] to the (paywalled) nature paper, for those who have access. [0]https://www.nature.com/articles/s41929-022-00865-5 https://www.nature.com/articles/s41929-022-00865-5 (Don't you just love walled academia?)
- nephanth 4y agoSci-hub is your friend
- AlexCoventry 4y agoTo the best of my knowledge, sci-hub has not been taking up new articles for quite a while.
- nephanth 4y agoOw you're right I wasn't aware of that
- throwaway742 4y agoI usually have had good luck emailing the authors. Often they include related resources and I get the distinct feeling I made their day.
- enslavedrobot 4y agoThis stuff is not competitive with electrochemical methods. A big problem with these methods, besides abysmal efficiency is that the light that drives the photochemical processes has some probability of generating side reactions that destroy the artificial enzyme. Nature overcomes this with unbelievably complex protein repair structures that literally swap out defective proteins for new ones. We have zero chance of replicating this type of thing anytime soon. Bio oil from algae is much closer to practical utility than this tech. And electrochemical CO2 reduction will be an even more scalable and practical solution in the near term in my opinion.
- hammock 4y ago>This stuff is not competitive with electrochemical methods. Which is why we need tax credits for this
- alwayslikethis 4y agoWhat? If we have money to spend on subsidizing stuff, we should subsidize the most efficient methods, which as parent implies, are the electrochemical methods.
- hammock 4y agoThe most efficient way to create methane is actually to drill a well, isnt it? I’m being downvoted for suggesting we incentivize something that will help us get off fossil fuels
- GeertB 4y agoIt seems that the proposed system is an improvement over plants, but not necessarily over the Sabatier reaction driven by energy captured by solar cells. Is that right? How would these compare?
- jijji 4y agoIt's good that a "university" is doing this, and not some individual... look what happened to Stan Meyer [0] [0] https://www.youtube.com/watch?v=gIAZFU2rAQE https://www.youtube.com/watch?v=gIAZFU2rAQE
- olivermarks 4y agoBiofuels are already being manufactured, are being used in motor racing with sophisticated octane blends and in road cars. Short explainer video https://coryton.com/lab/videos/how-can-we-decrease-carbon-emissions-from-transport/ https://coryton.com/lab/videos/how-can-we-decrease-carbon-em... Longer discussion Sustainable fuels; what are they & when will I be able to buy some? https://youtu.be/TyUiHafCdvM https://youtu.be/TyUiHafCdvM
- Maursault 4y agoIs there a deficit of methane? Methane is 80x more potent a greenhouse gas than CO2, and is responsible for 30% of Global Warming. Methane production is higher now than it has ever been. Hopefully this breakthrough leads to something useful, because we already have all the methane we could ever need.
- idlewords 4y agoMethane can be exchanged for goods and services
- frankreyes 4y agoNo, it's not the same. Producing methane from CO2 and sun is exactly the way to go green. Because we're not adding more, but just recycling methane from CO2. The issue for global warming is adding more CO2 and more methane to the atmosphere by taking it from underground, while this approach does not.
- Maursault 4y agoGot it. ><
- leoedin 4y agoThe important distinction is where the carbon comes from. If the methane comes from the ground, it's adding carbon to the carbon cycle. This is why we're in such a pickle. If the carbon comes from the air, or trees, or anything that pulled it from the air recently, then the methane is just another form of the carbon already in our atmosphere. Yes, it's a potent greenhouse gas - but it isn't a permanent one. Methane is oxidised in the atmosphere into CO2 eventually.
- Maursault 4y agoThank you. ><
- photochemsyn 4y agoThis looks interesting enough, but it really won't scale, as it relies on complex molecular assemblages with an iridium center, and iridium is quite rare as far as elements go. The paper is paywalled but the linked supplemental information shows the structures (pdf), Fig 8 is probably the most informative: https://static-content.springer.com/esm/art%3A10.1038%2Fs41929-022-00865-5/MediaObjects/41929_2022_865_MOESM1_ESM.pdf https://static-content.springer.com/esm/art%3A10.1038%2Fs419... Practically, separating the hydrogen production from water step from the carbon dioxide reduction step is the more plausible route to industrially significant production. Fundamentally I'm pretty sure making what's called 'synthesis gas' (H2 + CO) and feeding that into the well-known Fischer-Tropsch process is the route to long hydrocarbons (i.e. jet fuel) starting with atmospheric CO2 and water, the challenge there is making the CO from the CO2 efficiently. Alternatively, hydrogen and CO2 can be directly reacted over a cobalt catalyst, producing smaller hydrocarbons like methane and perhaps up to five-carbon molecules at present: "Cobalt Catalysts Enable Selective Hydrogenation of CO2 toward Diverse Products: Recent Progress and Perspective (2021)" https://pubs.acs.org/doi/10.1021/acs.jpclett.1c03043 https://pubs.acs.org/doi/10.1021/acs.jpclett.1c03043 Trying to do it all in one go is scientifically interesting, but not very practical. Even plants break it down into the light reactions (splitting water while generating ATP and NADPH, energy-carrying coupler molecules) and dark reactions (capturing the CO2 and incorporating it into a bisphosphorylated sugar prior to feeding it into the reductive reactions that utilize the products of the light reactions). It's also not too surprising that plants are not super-efficient at this process, they're under broad evolutionary pressure for a wide variety of processes, such as taking up water and nutrients, reproducing, etc. that don't necessarily revolve around fixing as much carbon as fast as they possibly can. It similar to industrial nitrogen fixation in that manner (of course, atmospheric N2 is 80% of the atmosphere while CO2 is only, what is it now, 420 parts per million).
- TheDudeMan 4y ago> The biggest challenge many people don’t realize is that even nature has no solution for the amount of energy we use. Good thing we split the atom.
- jdmtheNth 4y agoEven that will have its limit. We need to reduce our reliance on electricity.
- ck2 4y agoNot the same fuel but as far as "energy shortage", just a reminder we allow the fracking industry to burn-off $100 Million of natural gas into the atmosphere every day in the USA Simply so they can get to the more profitable oil. Absolutely ridiculous waste and damage.
- ETH_start 4y agoAre battery electric cars still viable in a world where renewable electricity can be converted into hydrocarbon feedstock to produce gasoline?
- MrStonedOne 4y ago[dead]
- Tade0 4y agoCombustion vehicles have other externalities, like contributing to the city heat island effect. All in all even a compact car going through the city is equivalent to a 5-10kW heater. Also gasoline combustion doesn't just produce CO2. Emissions include NOx, CO, unburnt hydrocarbons - even in this day and age it's a significant amount.
- jabl 4y agoThe electricity-to-wheel efficiency is vastly better for EV's than by creating synthetic hydrocarbons and burning those in an ICE.
- jillesvangurp 4y agoOnly once that can be done cheaply. Which so far is not the case. Basically electric cars are cheaper to drive than cars burning fossil fuels which in turn are cheaper to drive than cars burning synthetic fuels. As prices of things like batteries and renewables come down. Synthetic fuels might become cheaper than fossil fuels since you typically need lots of energy for producing synthetic fuels. If the amount of energy gets low enough it might get close enough to simply charging a battery with the energy and using it. But we're a very long way from that.
- moremetadata 4y agoI've been biologically creating methane fuel for as long as I can remember, so does this mean we need to destroy the sun in order to prevent global warming?
- 5ersi 4y ago"The trouble is that photosynthesis is built to create carbohydrates, which are great for fueling us, but not our cars..." Who the f* writes this articles?
- frankreyes 4y agoIt's funny because when you cook your food using methane created from such methods, it means that you're cooking food with solar power.
- j_maffe 4y agoFeynman was a bit ahead of you there: https://www.youtube.com/watch?v=N1pIYI5JQLE https://www.youtube.com/watch?v=N1pIYI5JQLE
- beeforpork 4y agoCody has an example of how to generate oil out of algae and sun light: https://www.youtube.com/watch?v=64cEmjtwRgw https://www.youtube.com/watch?v=64cEmjtwRgw Very interesting stuff! As others already noted, this is probably a more efficient and more robust technology.
- jabl 4y agoAFAIU algae fuel has been researched since the 70'ies, with little to show for it. Recently Exxon quietly cancelled their algae fuel project. One wonders if it was ever supposed to achieve something or was it just greenwashing.
- megaman821 4y agoAlgae fuel makes little sense. To grow enough algae for fuel usage, you would have to use a lot of fertilizer. The fertilizer would be made from natural gas. So it would just be a giant scheme of hiding natural gas usage behind green fuel, but worse since it would take more natural gas than just using it directly.
- Robotbeat 4y agoNo numbers in this article?