[HN Gopher] UC reactor converts carbon dioxide to fuel
       ___________________________________________________________________
        
       UC reactor converts carbon dioxide to fuel
        
       Author : gmays
       Score  : 218 points
       Date   : 2021-09-24 16:31 UTC (6 hours ago)
        
 (HTM) web link (www.uc.edu)
 (TXT) w3m dump (www.uc.edu)
        
       | eganist wrote:
       | I'm less interested in this as a climate change remedy (it's not)
       | and more interested in this for its terraforming potential.
       | 
       | What are the benefits and risks from just bleeding spare methane
       | into the atmosphere after any refueling reservoirs are topped
       | off? I'd think it'd be useful in raising temperatures on the
       | planet, though that's only one terraforming component.
       | 
       | (I'm very dangerously not an expert on this)
        
         | rale00 wrote:
         | Methane is fairly short-lived in the atmosphere, at only 12
         | years, so it probably wouldn't be particularly effective at
         | terraforming mars. Perfluorocarbons or sulfur hexafluoride can
         | stick around for thousands of years, so they would probably be
         | a better place to start.
        
           | ncmncm wrote:
           | Current SF6 level (four orders of magnitude more heat-
           | trapping than CO2, by weight) accounts for 10% of heat
           | forcing. How the heck do we get that stuff out of the
           | atmosphere?
           | 
           | There is a replacement, now, for SF6, for use in power
           | stations and wind turbines. Now the SF6 in use needs to be
           | pumped out and disposed of safely, and SF6 actually banned.
           | And, we have to persuade China to replace theirs too.
        
       | bialpio wrote:
       | I wish they addressed the fact that methane that they will be
       | producing is said to be an even more potent greenhouse gas than
       | carbon dioxide. Are there any worries about the leakage for
       | example?
        
         | hannob wrote:
         | This is an important point. Not for the "we'll build a gas
         | station on mars"-scenario, but for the "we'll propose this as a
         | climate solution".
         | 
         | Every way of replacing natural gas with some other source of
         | methane - be it the sabatier process or biogas/biomethane - has
         | this problem. It can only be a climate solution if you can
         | bring leaks down close to zero, which is very challenging.
         | 
         | It also makes one wonder whether e-methane is really such a
         | good idea or whether you'd rather look at other chemicals like
         | ammonia or methanol.
        
           | throwawayboise wrote:
           | Methane is produced naturally in vast quantities by decaying
           | organic matter, cow farts, released from volcanoes, natural
           | reservoirs, etc. I doubt that some small leaks in an
           | industrial process would make a real difference. It would
           | probably be undetectable in comparison to the leaks in our
           | current natural gas infrastructure that we use for heating
           | homes, cooking, and electrical generation.
        
             | bialpio wrote:
             | This may very well be the case that it's a non-issue, but
             | an article that only mentions the good parts without even
             | acknowledging potential problems with the solution makes me
             | think "what else did they not mention that a lay-person
             | like me wouldn't know about?".
        
         | dylan604 wrote:
         | Sure. If you're using the methane as rocket fuel that is
         | leaking, then nobody likes a rocket leaking fuel. That tends to
         | not end well.
        
         | jandrese wrote:
         | Starting a greenhouse effect on Mars would help it become more
         | livable by humans.
        
           | Synaesthesia wrote:
           | Do you realize the amount of effort we would have to put in
           | to make it habitable? And the time scales involved?
        
           | bialpio wrote:
           | Part of the article speaks about the uses that are a bit
           | closer to home. I'm not that worried about Mars, that part is
           | still SciFi to me and I probably won't live long enough to
           | see it become reality. :-(
        
       | [deleted]
        
       | lizknope wrote:
       | The article claims they are already converting CO2 to fuel on the
       | ISS. This process has been TESTED but we aren't using it right
       | now.
       | 
       | Article claims:
       | 
       | > Known as the "Sabatier reaction" from the late French chemist
       | Paul Sabatier, it's a process the International Space Station
       | uses to scrub the carbon dioxide from air the astronauts breathe
       | and generate rocket fuel to keep the station in high orbit.
       | 
       | Reality:
       | 
       | We just shipped a new CO2 scrubber a few months ago
       | 
       | https://www.nasa.gov/centers/marshall/news/releases/2021/mar...
       | 
       | For LONG space missions or colonies
       | 
       | https://www.eni.com/en-IT/scientific-research/space-free-co2...
       | 
       | The ISS is constantly falling back to earth. It maintains its
       | orbit with thrusters on the Zvezda module or a visiting
       | spacecraft boosts it higher
        
         | 5faulker wrote:
         | Space junk piling up as we speak.
        
         | dotancohen wrote:
         | The Sabatier reaction is very energy intensive. It is pretty
         | much the basis of Musk's demonstrations of cities on Mars,
         | powered by lots of solar power. It has other advantages for
         | human colonization as well, such as producing oxygen as a
         | byproduct.
        
         | gpm wrote:
         | The ISS uses rechargeable zeolite beds for CO2 scrubbing, they
         | don't need a new one frequently, and the fact that we shipped a
         | new one is coincidence.
         | 
         | Zeolite is a mineral, you get a bunch of small pellets of it in
         | a bed, and run air over it while cooling it. The CO2 (and H2O)
         | stick to it while everything else goes over it. Once you're at
         | capacity you vent it to space and heat it, the CO2 (and H2O)
         | leave the bed (into space) and recharge it for the next cycle.
         | Repeat forever.
         | 
         | The consumables here are the small amount of gasses sent
         | overboard, and energy, nothing else.
         | 
         | (And you use multiple of these beds because capturing CO2 is
         | exothermic, and venting CO2 is endothermic, so you want to run
         | a heat exchanger between the two beds in opposite cycles to
         | minimize energy usage)
        
           | dexwiz wrote:
           | If both operations are exothermic, why the heat exchanger? I
           | would assume one process would need to be endothermic.
        
             | _Microft wrote:
             | There is a typo. The answer is in the second paragraph:
             | 
             | "Once you're at capacity you vent it to space _and heat it_
             | , [...]"
        
             | gpm wrote:
             | Fixed the typo
        
           | rtkwe wrote:
           | The new scrubber sounds like it's not using the old zeolite
           | bed system but one based on molecular sieves. But you're
           | otherwise right that they're not really turning that CO2 into
           | anything on the regular beyond the limited ISRU
           | experiment(s).
        
             | gpm wrote:
             | Zeolite is a molecular sieve. That's just a fancy word for
             | "material that selectively holds on to some types of
             | gasses" (CO2 and H2O in the case of zeolite).
             | 
             | I haven't followed the new bed system though, I'd be very
             | interested to know if it was using a different molecular
             | sieve (and somewhat surprised if they are).
        
               | rtkwe wrote:
               | Ah yeah reading a bit closer further down they mention
               | it's a 4 bed system and this is largely an iterative
               | improvement instead of a new system entirely.
        
           | rolleiflex wrote:
           | If they're not recycling CO2 into O2 and instead venting CO2
           | to space, does that mean ISS is constantly losing gas and it
           | needs an ongoing resupply of oxygen all the time?
           | 
           | I thought oxygen was used fast enough to make resupply
           | impractical, but perhaps there are in fact gigantic tanks of
           | O2 under immense pressure somewhere aboard the ISS.
        
             | mzs wrote:
             | https://en.wikipedia.org/wiki/ISS_ECLSS#Oxygen_generating_s
             | y...
        
             | gpm wrote:
             | Yes, and sort of.
             | 
             | The ISS is constantly losing gas, I believe that the
             | primary source of new O2 is actually electrolysis of water,
             | not pressurized tanks, but that they do also have
             | pressurized tanks as a backup.
             | 
             | A person breathes out roughly 1kg of CO2/day, and it
             | follows you breathe in about the same amount of O2, not an
             | impossible amount of mass to resupply.
        
               | azernik wrote:
               | And, to complete the equation: that carbon comes up in
               | the form of food.
        
               | Zababa wrote:
               | > A person breathes out roughly 1kg of CO2/day
               | 
               | I've heard that you mostly love weight by breath, and
               | wondered what was the actual limit. Thanks for that info.
        
               | nielsole wrote:
               | Just remember that only the C part makes you lighter as
               | the O2 comes from the air. So based on that number it's
               | 375g/day (edit: it's 273g)
        
               | gpm wrote:
               | I get 273g/day? C is lighter than O.
               | 
               | Also... this is a typical number for a typical lifestyle,
               | I believe it can vary substantially if you exercise a
               | lot.
               | 
               | Also... I know nothing about wait loss, but surely a lot
               | of the mass is in water?
        
               | nielsole wrote:
               | Thanks for pointing out that mistake. I think people also
               | breath out quite a bit of water. So total weight loss
               | from breathing will be bigger than the 273g
        
               | fho wrote:
               | > 1kg of CO2/day
               | 
               | which is crazy low if you put it in perspective and see
               | that (gas powered) cars release about 0.2 kg of CO2 ...
               | per kilometer.
        
               | makeitrain wrote:
               | That's insane, I didn't realize it was that much. If we
               | could see cars drop carbon turds on the road instead of
               | venting it invisibly in the air we'd all be freaking out
               | right now.
        
               | NickNameNick wrote:
               | Well, we used to have horses...
               | 
               | There's a reason all the old buildings in big cities are
               | elevated a few steps above street level...
        
               | fho wrote:
               | Yep ... that's about two chocolate bars every kilometer
               | ... and that has not really changed too much with newer
               | motor generations as it is mostly a function of how much
               | gas is used.
        
       | Animats wrote:
       | It's a clickbait title, like the "fuel from water" people and the
       | "hydrogen economy" people. Yes, with enough energy you can crack
       | hydrocarbons out of combustion products. This is only useful if
       | you have plenty of energy but it's not in a portable form
       | suitable for rockets. As a means of removing CO2 from Earth's
       | atmosphere, it's hugely inefficient. If you have that much
       | electricity around, use the electricity, don't make hydrocarbons
       | so you can burn them again.
        
       | mirekrusin wrote:
       | We just need long pipe from Earth to Mars to pump out CO2 there.
       | It has to be long in case it gets entangled with the Sun. The
       | best is to fund it from crypto tokens. Winning Elon's XPrize
       | should buy few km of McDonald's straws to kick it off.
        
         | selimthegrim wrote:
         | Hey, it could happen.
        
         | xondono wrote:
         | Don't give Musk more ridiculous ideas, he might just get them
         | funded!
        
         | jerf wrote:
         | For giggles: A 3 square-foot pipe from here to Mars at Mars'
         | closest point of approach would hold about 31.7 million metric
         | tons of CO2 at atmospheric pressure [1], which looks to be
         | about 2 day's worth of US emissions.
         | 
         | [1]:
         | https://www.google.com/search?q=38.6+million+miles+*+3+feet%...
        
       | canadaduane wrote:
       | I wish this article spent more time on the science.
        
       | mlindner wrote:
       | Converting CO2 into fuell isn't the hard part. The hard part is
       | getting the CO2 out of the atmosphere in the first place.
       | 
       | We've known how to convert CO2 into fuel since the end of the
       | 19th century.
       | 
       | https://en.wikipedia.org/wiki/Sabatier_reaction
        
         | CodeGlitch wrote:
         | This I do not understand... why do we not build a nuclear
         | reactor out in the middle of no-where - easily accessible via
         | shipping - that has the job of taking CO2 out of the
         | atmosphere, and converting into liquid methane?
         | 
         | It can run 24/7.
         | 
         | Little running costs?
         | 
         | No one complaining about NIMBYISM.
        
           | MauranKilom wrote:
           | I am not exactly knowledgeable on the topic, but I believe
           | you might be underestimating the running costs. It's not like
           | you can just leave a nuclear reactor unattended and hope for
           | the best...
        
           | Manuel_D wrote:
           | It'd be much, much, more effective to hook up a nuclear
           | reactor to the grid to take fossil fuel plants offline, and
           | avoid releasing CO2 in the first place.
           | 
           | Though in the long term, it might be useful to do what you
           | propose to produce carbon neutral hydrocarbon fuel for things
           | that need exceptional energy density. Like air travel or
           | space launch vehicles.
        
             | CodeGlitch wrote:
             | > Though in the long term, it might be useful to do what
             | you propose to produce carbon neutral hydrocarbon fuel for
             | things that need exceptional energy density. Like air
             | travel or space launch vehicles.
             | 
             | Yes that's what I had in mind - thanks.
             | 
             | I do remain sceptical that electric cars will save us. If
             | everyone buys an electric car, and then plugs them in the
             | evening to charge - I'm not sure the grid will cope very
             | well. IMHO there is still a valid case for running cars,
             | trucks and trains on hydrocarbons.
        
         | kf6nux wrote:
         | One could say we've know how to convert CO2 into fuel from the
         | time we first learned agriculture.
        
         | amelius wrote:
         | > The hard part is getting the CO2 out of the atmosphere in the
         | first place.
         | 
         | From the article: The Martian atmosphere is composed almost
         | entirely of carbon dioxide.
        
       | robbrown451 wrote:
       | Title on HN should probably read "University of Cincinnati"
       | rather than UC. Even I, a graduate of University of Cincinnati
       | now first thought "University of California." (Admittedly I live
       | in California now)
        
         | [deleted]
        
         | FirstLvR wrote:
         | Can you imagine us non Americans trying to remember this
         | things...
        
           | myself248 wrote:
           | I just refer to everything by its domain name minus the
           | suffix. There is no "U of M", there is "UMich" and "Memphis"
           | and "UMT".
        
         | fnord77 wrote:
         | I'm impressed that University of Cincinnati snagged uc.edu
        
           | makeitrain wrote:
           | When you invent the internet but forget to register your own
           | domain... oops.
        
             | anamax wrote:
             | The University of California schools think of themselves as
             | independent entities, independent entities that just
             | happened to all pick the same school colors.
             | 
             | berkeley.edu (where "University of CA" is a subtitle),
             | ucla.edu, ucdavis.edu, etc.
        
               | fnord77 wrote:
               | sometime later:
               | 
               | https://www.universityofcalifornia.edu/
        
       | generalizations wrote:
       | The problem, in general, is obtaining the CO2. Ironically, in
       | industries where massive amounts of CO2 is needed (including
       | biodiesel production from algae), one of the cheapest ways to get
       | it is to just make it. Pulling it out of the air isn't feasible.
        
         | ehsankia wrote:
         | Pulling it out of the air isn't feasible.
         | 
         | What about pulling it right where it's mostly produced (heavy
         | polluting factories or electricity generators).
        
           | Manuel_D wrote:
           | Capturing it is difficult. It's coming out the end of a
           | turbine or smelter at very high temperatures. You need to
           | cool it and compress it down.
           | 
           | Then you need to secure a source of hydrogen. Over 90% of
           | industrial hydrogen comes from steam reforming which emits
           | CO2. So you'd need to build out massive electrolysis plants,
           | and power these plants with carbon-free energy.
           | 
           | Finally you'd need to run the Sabatier process, which also
           | needs energy.
           | 
           | It's much, much easier to drive down emissions by just
           | reducing the CO2 released in the first place.
        
         | burnte wrote:
         | https://singularityhub.com/2021/09/09/the-worlds-largest-dir...
         | 
         | The more we do it the cheaper it'll get.
        
       | yholio wrote:
       | No, enough with this nonsense. Capturing, liquefying and
       | transforming CO2 into fuel requires energy - due to thermodynamic
       | limits, much more energy than what the fuel can give back. You
       | then take that fuel, and... burn it into 25% efficient engines
       | that spew the very same CO2 back into the air, along with some
       | new carcinogenic fumes and acid-rain inducing nitrogen oxides?
       | 
       | No, just no, full stop. They way forward is electrification of
       | everything, using only carbon-neutral energy, renewables
       | &nuclear. No hydrogen, no methane, no electric to fuel, let's not
       | do these physical stupidities to keep dying industries alive.
        
         | eightysixfour wrote:
         | I was with you until no hydrogen. While it is inefficient in
         | compared to batteries, as long as it is being produced with
         | carbon-neutral energy then there are areas where its kWh/kg
         | ratio and comparatively rapid refilling are extremely
         | beneficial.
        
           | yholio wrote:
           | You should take that kWh/kg figure with a kg of salt. You
           | need a heavy COPV tank to store hydrogen under pressure, a
           | 100 kg tank might store only a few kg of fuel, take 400 liter
           | to do so, and be comparable with a 30l conventional fuel
           | tank: https://www.fsec.ucf.edu/en/consumer/hydrogen/basics/do
           | cumen...
        
             | eightysixfour wrote:
             | Sure, and using it for small vehicles seems like the worst
             | place to use them. I'm thinking more about vehicles that
             | need significantly more fuel - diesel electric trains,
             | container ships, airplanes, etc.
             | 
             | It won't work in all of those situations since hydrogen is
             | so hard to manage, but there are a number of applications
             | where batteries are not the right answer yet. Battery
             | weight is going to scale close to linearly with capacity,
             | hydrogen tank weight should not.
        
               | ncmncm wrote:
               | LH2 tanks on aircraft, insulated with aerogel, can be
               | very light. But the extra volume will mean a need for new
               | airframes.
               | 
               | Trains and ships, and maybe trucks, will do better with
               | ammonia. The tanks are bigger, but those have room, and
               | existing engines can burn ammonia with just changes to
               | plumbing.
        
         | missedthecue wrote:
         | You are correct that they can't break the laws of
         | thermodynamics, but they don't need to in order to have a
         | workable business model. The reason is because you don't need
         | it to result in more energy than you put in. You just need it
         | to result in more revenue than input costs. This is practically
         | possible because different energy forms have different costs
         | and they're not all substitutable for each other. For instance,
         | electricity may become a lot cheaper than liquid fuel, but you
         | can't electrify a long range airliner, or most military
         | equipment. So in a world where a watt of electricity can be
         | bought for 1/3 the price of a watt of kerosene, using 2 units
         | of electricity energy to make 1 unit of liquid fuel energy
         | would be economical. (made up numbers, you get the point)
        
         | [deleted]
        
         | realusername wrote:
         | Thermodynamics is about energy not CO2, you can design negative
         | CO2 devices and we even have proof in nature of that since
         | that's what trees are doing.
        
           | wyager wrote:
           | There are several conceptual issues here, but one of them is
           | that trees require energy from sunlight to turn CO2 into
           | other things.
        
             | realusername wrote:
             | Yes but we don't have an energy problem, we have a CO2
             | problem and there's no law of physics preventing to absorb
             | more CO2 than you emit.
        
               | diarrhea wrote:
               | That's true but assumes the captured CO2 remains that,
               | captured. The article revolves around the idea of turning
               | CO2 into _fuel_. Fuel which is burned, releasing that
               | same CO2 again while having wasted a lot of intermediate
               | energy. At best, that energy was renewable and would 've
               | been curtailed otherwise (hence wasted). Then you didn't
               | "use energy" but it was still an utterly useless
               | exercise.
               | 
               | Now, if the carbon remains captured and the energy for
               | capturing is renewable, we are in business. I'm not aware
               | that is done on a meaningful scale yet though.
        
           | peteradio wrote:
           | But thats not what this is. Fuel is intended to be consumed,
           | seems like this is at best carbon neutral assuming totally
           | neutral power source. Are our current power sources on
           | average neutral or are they much more carbon positive?
        
             | realusername wrote:
             | > But thats not what this is. Fuel is intended to be
             | consumed, seems like this is at best carbon neutral
             | assuming totally neutral power source
             | 
             | Indeed, that's their goal, the issue is that currently we
             | emit a lot so even making the fuel close to neutral (minus
             | production inefficiencies) is already a huge progress.
             | Going negative isn't for tomorrow unfortunately.
        
           | marginalia_nu wrote:
           | The problem is that this requires reversing entropy. Turning
           | CO2 into something that can burn into CO2 requires more
           | energy than you get back while burning it, even in an optimal
           | engine. This is true if humans reverse entropy or if trees do
           | it.
        
             | realusername wrote:
             | Economics are a different story yeah, there's no way to
             | make carbone absorption economically possible without some
             | carbon scheme designed by the country. They won't happen on
             | their own that's for sure, that's where legislation should
             | come in place.
        
             | DennisP wrote:
             | It's not an energy source, it's a battery.
        
         | colordrops wrote:
         | Agreed that the future is electrification, but it will take
         | trillions of dollars and a lot of time to replace all internal
         | combustion engines. What should we do in the meantime? It seems
         | that using renewable energy to make carbon neutral fuels for
         | these vehicles makes a lot of sense. What is "nonsense" about
         | this?
        
           | mrguyorama wrote:
           | It would take more time, energy, money, and resources to
           | build out enough solar and wind (etc) to turn enough CO2 into
           | enough fuel for all our cars than it takes to just replace
           | the cars with electric ones and use that massive solar and
           | wind grid to just power them straight
        
             | colordrops wrote:
             | It's not all or nothing, and further more the electricity
             | from solar and wind is fungible and can be used for either
             | fuel generation or direct usage by electric cars, so it
             | would serve us either way, no matter how long it took.
             | 
             | These things are not contradictory. We can build out more
             | renewable electricity supply, replace with electric cars,
             | and generate carbon neutral fuel all at the same time. You
             | are underestimating how long and difficult the ICE
             | replacement is going to take. It's not like a single
             | organization can just wave a wand and all gas cars would be
             | replaced over night.
        
               | yholio wrote:
               | In Europe, fosil fuel engines are already 2-4 times more
               | expensive to run than electrics. In 11 years, which is
               | the average age of a car in Europe, the majority of
               | private vehicles will switch naturally for purely
               | economic reasons. In 20 years, the same will be true for
               | busses, trucks & tractors.
               | 
               | And it will be driven solely by better economics.
        
               | diarrhea wrote:
               | And what do you get by replacing one ICE vehicle in
               | Europe with an electric one?
               | 
               | You get _two_ cars. A shiny new electric one running in
               | (Central) Europe, and that same old stinky ICE one
               | running in Eastern Europe, Asia or Africa.
               | 
               | The poorer countries will enjoy an influx and thus price
               | decrease of valuable cars and happily drive them for
               | decades to come.
               | 
               | The problem of course is that the planet doesn't care.
               | Europe got cleaner but the planet got worse. Whereas
               | Europe can outsource its dirty issues (waste, emissions,
               | ...), the planet cannot. It stops there and we all lose.
               | 
               | I think the vast introduction of and blind focus on
               | e-mobility is a mistake. Other areas are much more
               | significant sources for GHG (industry, heating, A/C).
        
         | it_citizen wrote:
         | I get that blue hydrogen might be a controversial topic but
         | isn't there at least a case to make for green hydrogen in some
         | sectors that might be hard to electrify such as aviation? Or
         | even as an alternative storage solution since the effort to
         | scale up nuclear seems pretty much dead in the water.
         | 
         | I know it is a long shot: it is not yet competitive, there are
         | still very few electrolyzers but some part of the world such as
         | Europe seems pretty committed to try to make it work.
        
         | btilly wrote:
         | The title needs to be changed. Because this isn't about climate
         | change, and the research, contents of the article, and current
         | article title are clear on that.
         | 
         | This is about space exploration. Literally it is about how to
         | make fuel on Mars so that we can make the round trip without
         | having to deliver fuel so we can make it back.
         | 
         | And, sorry, but there is no way with current technology to
         | launch significant payloads into space using electric.
        
         | _Microft wrote:
         | It can make sort of sense for applications for which the energy
         | density of the fuel (like for airplanes or rockets) matters a
         | lot. The energy density of current generation lithium ion
         | batteries is insufficient to allow for long-range flights.
         | Synthetic fuels could allow planes to still travel around the
         | world while being effectively net zero emitters because the
         | CO_2 was harvested from the atmosphere (or another, unavoidable
         | CO_2 source). The production of the fuel might be inefficient
         | but at least it would work.
        
           | ncmncm wrote:
           | Liquid hydrogen LH2 electrically synthesized on-site at
           | airports from excess peak production will be important in
           | aviation after maybe 2035 (provided civilization doesn't
           | collapse first). Aside from LH2's usefully extreme energy
           | density, pumping less CO2 directly into the stratosphere
           | would be good.
           | 
           | We may reasonably expect production of the needed aerogel-
           | insulated LH2 tankage to be mature by then.
        
             | MauranKilom wrote:
             | Asking as someone only remotely familiar with hydrogen as a
             | fuel: Don't you have the problem of tanks and pipes
             | becoming brittle from hydrogen diffusing into the material?
             | Are there existing/upcoming solutions for this? I was under
             | the impression that this is a pretty fundamental problem
             | with hydrogen being just a proton essentially..
        
             | _Microft wrote:
             | You need to consider the volumetric energy density, not the
             | specific energy (which is energy per mass). LH2 has a high
             | specific energy but pretty low volumetric energy density
             | which means that much larger tanks are needed to store the
             | same amount of energy than for other fuels.
             | 
             | The conditions for storage of LH2 and demands on materials
             | in contact with LH2 are much harder than for e.g. methane.
        
           | yholio wrote:
           | There is already a good solution for planes: ammonia,
           | manufactured efficiently from green hydrogen. You will never
           | be able to use gaseous or liquid hydrogen on planes due to
           | the high volume, weight and risk associated with known
           | storage methods.
           | 
           | Ammonia seems to strike the right balance:
           | https://www.ammoniaenergy.org/articles/zero-emission-
           | aircraf...
        
             | _Microft wrote:
             | How are they planning to work around ammonia's toxicity
             | problem? It's fatal if breathed in at concentrations like
             | we currently have CO_2 in the atmosphere (> ~400ppm). If a
             | tank with conventional jetfuel or methane springs a leak or
             | has to be dumped, you've got a huge problem. If that
             | happens with an ammonia tank, you are most likely toast
             | either way.
        
         | blacksmith_tb wrote:
         | We'll just use that fuel to make plastic, and scatter it all
         | over the surface of the planet. So it's really just a
         | continuation of the ad hoc sequestration program already under
         | way.
        
         | qw3rty01 wrote:
         | In the article, the idea was to store excess green electricity
         | (from solar/wind farms for example) by capturing CO2 that is
         | generated from fossil fuels. I do agree that claiming it will
         | address climate change is a bit of a stretch, since that CO2 is
         | still going back into the environment when the methane is used,
         | but it does mean getting more energy per unit of CO2.
        
         | dang wrote:
         | Please don't fulminate. That's in the site guidelines
         | (https://news.ycombinator.com/newsguidelines.html), because it
         | tends to produce low-quality discussion which we're hoping to
         | avoid here. I'm sure you can make your substantive points
         | thoughtfully, so please do that instead.
        
       | ridaj wrote:
       | For Mars? What would carbon-based fuel on Mars be burned with?
       | There's not much O2 there!
        
       | adamtheclayman wrote:
       | There's a company in Israel that's recently patented and is
       | commercializing this process described of using transiently cheap
       | or free renewable energy surplus to methylate captured/scrubbed
       | CO2 with the Sabatier reaction, then burning it at the time and
       | place of their choosing as "renewable" natural gas.
       | 
       | Standard Carbon: https://www.standardcarbon.com/
       | 
       | Standard Carbon Patent:
       | https://patents.google.com/patent/US11091408B2/en?oq=11%2c09...
        
       | asasidh wrote:
       | convert Co2 to methane which is a more potent agent for global
       | warming. what could go wrong
        
         | rtkwe wrote:
         | For Mars that's not so much of an issue. Even if we did release
         | a lot of methane warming up Mars isn't a bad thing in fact it's
         | something we may try eventually intentionally to make it less
         | inhospitable.
        
       | invisible wrote:
       | It's been seemingly impossible to motivate the world to switch to
       | alternatives to fuel. We're between a rock and a hard place with
       | society and the environment.
       | 
       | It seems like there isn't even a conspiracy, it's just a
       | combination of poor choices, greed, and new technology. Solar is
       | great, but often it's more expensive than just consuming grid
       | power or has unpredictable payoffs. Wind has a lot of upfront
       | costs. Massive batteries are just starting to roll out. Energy
       | companies are trying to keep prices low in the short-term and
       | keep things reliable, so they mostly use cheap and plentiful
       | fuel. Consumers without a lot of money can't put the capital down
       | for a new car, so they buy used or cheap. It happens that most
       | used/cheap cars use petrol-based fuel. Additionally, car
       | companies have a product that sells, why risk that or their
       | reputation?
       | 
       | Finally, you have the government deciding policy based on much
       | more than just the environment.
       | 
       | Perhaps this will create a better storage mechanism, but
       | addressing getting to carbon neutrality feels very dreary.
        
         | SV_BubbleTime wrote:
         | > It's been seemingly impossible to motivate the world to
         | switch to alternatives to fuel.
         | 
         | The impossible part is we have yet to discover a density/cost
         | comparison to hydrocarbons.
         | 
         | No one is going to "switch" to something that isn't as good as
         | the existing option. Couple this with "but electric cars!" that
         | often are still just coal powered.
         | 
         | Plastics, military, actual logistics, China, we're going to
         | burn every drop of oil. We all better hope someone is working
         | on sequestering options!
        
           | invisible wrote:
           | If you're taking what I said to mean "of course individuals
           | should just do better," I definitely didn't mean to imply
           | that. Exactly the opposite, actually.
           | 
           | It's a bunch of smaller decisions that are hampered by new
           | technology and lack of economies of scale, among many other
           | compounding factors that result in poor
           | consumer/business/utility/government choices (for the
           | environment). I think sequestering may be an important part
           | of that, but it's still new technology.
        
         | s1artibartfast wrote:
         | >Finally, you have the government deciding policy based on much
         | more than just the environment.
         | 
         | I feel like this is the crux of your problem. People and
         | governments have multiple priorities to balance
        
         | president wrote:
         | If it was really an issue, wouldn't free market forces have
         | paved the way to widespread fuel alternative consumption a long
         | time ago? Sure you can force everyone to stop using gasoline
         | and buy an electric car but there are costs to that. I think
         | most people believe there are more dire issues that need fixing
         | and funding.
        
           | mattnewton wrote:
           | I think the issue is that the costs of using fossil fuels are
           | "external" to the purchaser, so a market solution doesn't
           | work until the negative externality of pumping co2 into our
           | shared atmosphere can be accounted for.
           | 
           | It would be like expecting people who dump their industrial
           | waste upstream in a river to be corrected by market forces -
           | the market will probably choose that people don't care about
           | the down river people as long as they get their goods
           | slightly cheaper.
           | 
           | Also a wrinkle in a pure market based solution is that the US
           | substantially subsidizes fossil fuels because I think the
           | 70's taught politicians that fuel price shocks will get them
           | voted out immediately. https://www.eesi.org/papers/view/fact-
           | sheet-fossil-fuel-subs...
        
           | invisible wrote:
           | I'm not sure I understand your point. The free market is
           | slowly moving toward alternative fuels, albeit slowly. That's
           | part of why your local energy utility is likely using a
           | combination of sources. It's why you can see solar panels
           | when you drive around any non-shaded resident affluent
           | communities. Many governments around the world see the issue
           | and have made agreements to address it, insofar as they can
           | and on a timeline of a century.
        
           | orthecreedence wrote:
           | The capitalist solution to climate change is building condos
           | in Antarctica. Capitalist markets are probably the most
           | short-term problem solving mechanism you could ever find for
           | an economy.
           | 
           | > I think most people believe there are more dire issues that
           | need fixing and funding.
           | 
           | No, they're stuck in a shitty system that doesn't allow them
           | to price resources according to their externalities. People
           | aren't going to opt to pay more for fossil fuels than they
           | have to because it would require a critical mass of buy-in.
           | The only solution is taxation, but that doesn't work either
           | because the system offers no safety nets and gasoline
           | suddenly jumping to $20/gallon (which is what it should cost
           | now) would be financially devastating to citizens.
           | 
           | Markets work great at lower populations, and now we're
           | beginning to see their failure modes when population has
           | skyrocketed and rampant resource consumption causes
           | existential damage. Everyone _knows_ it 's a problem, but
           | there's no systemic way of solving it.
           | 
           | We're now at a point in humanity where _supply and demand_
           | alone are insufficient mechanisms to organize an economy.
        
           | [deleted]
        
       | btilly wrote:
       | This isn't the only team trying this. See
       | https://www.universityofcalifornia.edu/news/making-methane-m...
       | for another team working on the same thing for the same purpose.
       | 
       | It is worthy of note that the process that is described is
       | exactly the one that Elon Musk was already planning to use on
       | Mars. This is exactly why finding water on Mars is critical to
       | his plans, and is also why Starship is designed to run on
       | methane-oxygen. (Starship will be the second methane rocket ever.
       | And the first, Starhopper, used the same raptor engine.)
       | 
       | It is also worth pointing out that producing methane here on
       | Earth for use around Earth is not particularly helpful. Methane
       | is hard to store and is a better greenhouse gas than carbon
       | dioxide. Then if you use it for a rocket, you put that carbon
       | dioxide back in the atmosphere. We benefit a bit from the shade
       | provided by the water vapor so it isn't quite net neutral, but it
       | is pretty close.
        
         | [deleted]
        
         | trevcanhuman wrote:
         | Ironically, both are UC. I even though at the beginning that
         | OP's article was from the University of California. Pretty big
         | coincidence.
         | 
         | > It is also worth pointing out that producing methane here on
         | Earth for use around Earth is not particularly helpful. Methane
         | is hard to store and is a better greenhouse gas than carbon
         | dioxide.
         | 
         | Couldn't we run the methane through one of those electric
         | generators used in farming for cows' feces ? I honestly don't
         | know how efficient these processes are, not an expert by any
         | means.
        
           | spiorf wrote:
           | > Couldn't we run the methane through one of those electric
           | generators used in farming for cows' feces ?
           | 
           | You get back the co2 and the energy you expended to make
           | methane in the first place.
        
       | tito wrote:
       | For anyone starting a carbon removal startup, check out AirMiners
       | http://airminers.org
       | 
       | For anyone who has been scouring the web to learn about carbon
       | removal and wants all the best stuff in one place, check out the
       | 5-week AirMiners Boot Up http://bootup.airminers.org
        
         | thinkling wrote:
         | Super interesting, thanks! Any idea what the timeline will be
         | on your fund?
        
         | ruffrey wrote:
         | Thank you so much for sharing this! Exactly what I've been
         | looking for.
        
           | tito wrote:
           | Sure thing! For a bit of customer interview, can you describe
           | your process so far to this point? Where have you been
           | looking, what got you interested, etc. And when you say
           | "exactly what you were looking for", what are you seeing?
        
         | Voloskaya wrote:
         | Or if you would rather do it on your own time I can recommand
         | the CDR Primer: https://cdrprimer.org/read
        
       | throwaway894345 wrote:
       | The actual title is "UC reactor makes Martian fuel" and the
       | subtitle is "A gas station on Mars? Engineers envision the
       | possibilities." But the submission title is "UC reactor converts
       | carbon dioxide to fuel to address climate change"?
       | 
       | While it does talk about applications with respect to carbon
       | capture, if we consume the fuel byproduct, presumably we just end
       | up with co2 in the atmosphere?
       | 
       | > "In the future we'll develop other catalysts that can produce
       | more products," said Zhang, a doctoral student in chemical
       | engineering.
       | 
       | So I guess if we produce products which sequester carbon then
       | maybe that would be useful, but this is purely speculative.
        
         | jl6 wrote:
         | > if we consume the fuel byproduct, presumably we just end up
         | with co2 in the atmosphere?
         | 
         | The process would still be great news if true, as it could be a
         | carbon-neutral source of hydrocarbon fuel for applications that
         | are hard to electrify, like aviation.
        
           | wrycoder wrote:
           | This is mainstream energy science.
           | 
           | Anthropogenic Chemical Carbon Cycle for a Sustainable Future
           | [0]
           | 
           | How to Make Carbon-Neutral Gasoline Out of Thin Air [1]
           | 
           | [0] https://pubs.acs.org/doi/abs/10.1021/ja202642y#
           | 
           | [1] https://nymag.com/intelligencer/2021/05/how-to-make-
           | carbon-n...
        
           | wibagusto wrote:
           | I just imagine the scramble to get carbon neutral allowing
           | huge carbon-processing factories and then we enter some kind
           | of carbon deficit, back in the same situation we are in--a
           | teetering balance between overconsumption and moderation.
        
             | chrisBob wrote:
             | If, some day in the future the oil companies all start
             | pushing hard for carbon capture, then we will know this is
             | a real possibility.
        
             | jl6 wrote:
             | To be clear, the solution to climate change is first to
             | stop burning fossil fuels, and then to start removing
             | carbon from the atmosphere. This technology won't help long
             | term removal of carbon if we just burn the resulting fuel,
             | but it might help displace fossils as a source for some
             | applications that would otherwise be at the very end of the
             | fossil ramp-down.
        
               | markkanof wrote:
               | With this technology, assuming it can capture large
               | amounts of carbon, couldn't some of it be converted to
               | fuel for current use and some of it sequestered. It would
               | certainly take longer to significantly reduce the amount
               | of CO2 in the atmosphere, but should still do the job.
               | Instead of introducing new CO2 into the atmosphere by
               | burning newly extracted oil, we would be sequestering
               | some and "recycling" some.
        
               | dotancohen wrote:
               | There still must be some input of energy. From what I
               | understand, the Sabatier reaction is really only viable
               | from an environmental perspective if it is powered by
               | some other non-carbon energy, such as solar or wind.
        
               | dTal wrote:
               | And if you have that surplus clean energy, you should
               | spend it powering things that would otherwise be powered
               | with fossil fuels - _not_ trying to offset someone else
               | 's emissions. Carbon removal only makes sense in a world
               | where nobody is burning _any_ fossil fuels, and we 're
               | trying to lower atmospheric carbon. Lower, not offset.
        
               | throwaway894345 wrote:
               | I accept the argument that offset schemes have difficult
               | practical problems, but at least theoretically "offset"
               | means "lower". It just means that your application isn't
               | necessarily reducing carbon. And it kind of makes sense--
               | for an airline to get carbon neutral it would require
               | immense investment in electric flight and decades of
               | research and then more decades of incremental rollout.
               | Instead that money and effort could be spent helping
               | reduce a _lot_ more carbon elsewhere _now_ (e.g.,
               | replacing coal power plants with equivalent solar power).
        
               | wrycoder wrote:
               | Which would only make sense if you were trying to
               | initiate the currently deferred glacial epoch.
        
               | throwawayboise wrote:
               | Yes, to convert CO2 to CH4 you need to break the C-O
               | bonds. This takes energy.
        
           | orthecreedence wrote:
           | From what I know, it's electricity intensive to make the
           | fuels. Now, if only we had a very scalable way to make
           | immense amounts of electricity that didn't depend on weather
           | in a world where the climate is now in disarray. Hmm...
        
             | admax88qqq wrote:
             | You're being unnecessarily negative IMO.
             | 
             | The biggest challenge with renewables always cited is
             | storage. Cabrin neutral feul like this could potentially be
             | a good storage medium.
             | 
             | There's more than enough solar energy hitting the Earth's
             | surface to supply all our power needs, the challenge is
             | capturing, storing, and distributing this power.
             | 
             | After all, fossil fuels are just captured solar energy.
        
               | orthecreedence wrote:
               | Right, the operative keyword in my comment being
               | _scalable_. How many solar panels does it take to
               | generate the same amount of power _in a full day_ that
               | nuclear does _in a full day_? Now, are you assuming a
               | sunny day? What about cloudy days? What about weeks of
               | wildfire smoke blotting out the sun? Are you including
               | the energy it takes to create your fuel battery? How much
               | fossil fuels do we burn in manufacturing to cover the
               | Earth 's surface in enough solar panels to meet our
               | collective needs?
               | 
               | Storage isn't the only problem, and I mentioned this in
               | my comment: weather patterns are changing in unpredicable
               | ways. Building more weather-dependent power sources is
               | _stupid_ when we already have a great solution.
        
         | [deleted]
        
         | fozzyfozfoz wrote:
         | Yea that CO2 is not as easy to pump as sticking a drill in some
         | oil plump wet dirt and pumping away.
        
         | 300bps wrote:
         | _if we consume the fuel byproduct, presumably we just end up
         | with co2 in the atmosphere?_
         | 
         | It's necessary to compare the two things:
         | 
         | 1 - we drill out more fossil fuels and burn it
         | 
         | 2 - we convert atmospheric CO2 to fuels and burn it
         | 
         | #2 is theoretically infinite and CO2 levels never increase. #1
         | is very finite and the longer we do it the higher CO2 levels
         | increase.
        
         | riboflavin123 wrote:
         | The URL matches the submission title, at least. Perhaps the
         | content changed?
        
           | DiabloD3 wrote:
           | I concur, looks like the title changed, slug remained the
           | same.
        
             | throwaway894345 wrote:
             | That's amusing. The change must've occurred in the ~8
             | minute window between the submission and my comment, which
             | seems odd considering the article is 2 days old. Not
             | casting doubt, but remarking on coincidence.
        
               | temp0826 wrote:
               | A/B test caught in action possibly?
        
               | btilly wrote:
               | Most likely the fact that it appeared here caused someone
               | to look at it, realize that the title didn't match the
               | contents, and hurry to change it.
               | 
               | The old title really was egregiously bad. @dang, can we
               | get it fixed?
        
         | dang wrote:
         | There's more than one actual title. The submitter used the HTML
         | doc title, which is a legit choice, and they probably picked it
         | on the grounds that it was more substantive/less baity.
         | 
         | Since the climate change mention has turned out to be baity in
         | its own right, I took that bit out above.
        
           | throwaway894345 wrote:
           | Huh, makes sense. I didn't realize there could be more than
           | one title. Thanks for the clarification.
        
         | sfink wrote:
         | > if we consume the fuel byproduct, presumably we just end up
         | with co2 in the atmosphere?
         | 
         | If it replaces some amount of fossil fuel, it could still be
         | useful. I'm guessing the efficiency isn't great, though.
        
       | perfunctory wrote:
       | On the side note, anybody knows what happened to the prometheus
       | startup [0]? Are they still alive?
       | 
       | [0] https://news.ycombinator.com/item?id=19842240
        
         | twostorytower wrote:
         | Looks like they're still alive and well:
         | https://prometheusfuels.com/technology
        
       | whatever1 wrote:
       | I like how in the media publications for carbon capturing they
       | always forget to mention that these things need a ton of energy
       | to run.
        
         | qw3rty01 wrote:
         | They do mention it, just not directly:
         | 
         | > Right now we have excess green energy that we just throw
         | away. We can store this excess renewable energy in chemicals.
         | 
         | The idea is that it can be used to store excess energy from
         | green sources
        
           | brokensegue wrote:
           | unless we price carbon high enough this excess energy is just
           | going to get burnt into bitcoin
        
             | epistasis wrote:
             | Depends on the relative value of mining and fuel
             | manufacturing.
        
         | whatshisface wrote:
         | If people were willing to work through the issues with nuclear
         | power, running a bunch of nuclear plants to power the scrubbers
         | would be semi-reasonable.
        
           | epistasis wrote:
           | It's far more reasonable to use solar than nuclear for this,
           | solar has leapfrogged nuclear now.
           | 
           | The carbon capture startup founder of Carbon Engineering
           | talks about how he got this wrong, and how they switched
           | their plans from using nuclear to solar. Here's a talk from
           | two years ago on this:
           | 
           | https://www.youtube.com/watch?v=sYopOt9siLg
           | 
           | Note that many disagree with his optimism on the carbon
           | capture side of things, but the solar is generally accepted
           | by technologists.
        
         | korantu wrote:
         | This ton of energy on top what we already consume can be indeed
         | obtained from nuclear [0], without spending a lot of additional
         | material.
         | 
         | [0] https://medium.com/climate-conscious/nuclear-powered-
         | carbon-...
        
       | lmilcin wrote:
       | Don't get your hopes too high if you think this can be used to
       | scrub significant amount of CO2 from atmosphere.
       | 
       | Don't get me wrong, producing fuel from atmospheric CO2 is still
       | wonderful news.
       | 
       | But you know what they produce? Methane. And methane is what? It
       | is _A FUEL_. And what we do with fuel? We _BURN_ it. Once you
       | burn methane you get the CO2 back, for net ZERO effect on the
       | atmosphere.
       | 
       | The only way this works to help the climate is if you can use
       | thus produced methane to remove need for mining actual gas.
       | Unfortunately (or fortunately), we are already on the way to
       | reduce a lot of mining for energy by replacing it with
       | electricity. So according to Amdahal's law, the benefit is also
       | going to be small.
       | 
       | Producing and burying methane clathrate is still impractical and
       | would be very risky, because they can get resurfaced and then
       | methane is hundreds of times more potent as warming agent than
       | CO2.
        
         | diarrhea wrote:
         | It's even worse than zero net effect, it's negative, owed to
         | all the auxiliary inefficiencies. Add to that methane slip and
         | it's infeasible by a long shot.
         | 
         | The solution can never be to remedy surface-level GHG. The
         | sources need to remain buried and replaced by true renewables.
         | Anything else is just an afterthought, patching what's already
         | too little too late. Almost all fossil-based material that made
         | it to the surface will end up contributing to GHG.
        
           | CodeGlitch wrote:
           | Do not forget market forces: there would be a strong
           | incentive to improve upon the CO2 scrubbing technology, which
           | can then be used in the tech to permanently remove CO2 from
           | the atmosphere.
        
         | ncmncm wrote:
         | 24 times more.
         | 
         | You are better off just pumping the CO2 down there, instead,
         | and arranging for it to turn into rock.
        
           | [deleted]
        
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