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
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)
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.
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.
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.
You could probably get a similar reaction if fossil fuel sales were given in the equivalent of trees or fuel crops. Someone might question running to the store just for donuts if they imagined burning half of a tree or 40 pounds of grain or something in the process, rather than just a bit of gasoline.
Honestly I was not even aware of that ... A quick search shows that a 100 yo birch tree stores only about 15 kg CO² ... So your half a tree seems to be in the right ball park.
Also ... CO² is bad ... but at least is non-toxic compared to some of the other side products.
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.
Yep, engines definitely have improved over time. Still the Corolla is producing about 80 grams of CO² per km (which in Germany is the benchmark to get a E-plate).
You can easily walk tens of kilometers in a day. 10 km us basically nothing, 20 km would be somewhat taxing if you are unprepared ... But some (crazy) people are doing 100 km walks for "fun".
> Also... I know nothing about wait loss, but surely a lot of the mass is in water?
Not really. Yes, you loose water (and its weight) when you e.g. sweat a lot when exercising, but it gets replaced when you drink. More generally your body keeps the amount of water more or less at the same level through intake (drinking, but also water in food), urinating and sweating. There are short-term variations, but besides exceptional circumstances on a day-to-day basis the amount of water in your body should be pretty constant.
Real weight loss is through loss of muscles (not preferable) or loss of fat.
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
As a sanity check: fat is around 9 kcal per gram. In a day you use around 2000 kcal of energy or 222 grams of fat. Protein and carbohydrates are around 4 kcal per gram.
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).
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).
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.
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.
It does convert CO2 into "fuel" but the ISS just vents it into space. The utility for the ISS is getting the O2 back and being able to ship up water and use it for atmospheric regulation as well.
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.
> 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.
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...
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.
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.
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.
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.
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.
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.
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).
Depends on the cause of emissions. A few are not for purely energy but involved in some kind of chemical reaction. Concrete and Metal extraction are 2 examples. Having a way to offset is important in a cheap manner. Metal extraction esp is a prob as carbon reacts with several metal oxides and reduces it releasing heat. Since it generates heat and creates the final product, it prob more efficient then the alternative electrolysis route.
But yes offsetting CO2 produced due to energy is a waste.
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.
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.
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.
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?
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.
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.
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?".
You have to put that in perspective bit. Methane is a powerful greenhouse gas but it breaks down in a few years as well. And then there is the notion that there is quite a lot of it leaking in the atmosphere already through natural processes, melting of the permafrost, and indeed as a side effect of oil/gas production. You'd have to produce stupendous amounts of fuel to have leakage to an extent that it actually matters.
So, if we'd actually capture and burned the gas, there would be little to worry about. Especially considering we'd be getting less of it out of the ground in fossil form.
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. :-(
Essentially it would be almost infinitely easier to reverse all climate change on earth than to make another planet livable but it is in theory possible.
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.
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.
I had trouble believing that (astronomic scales always seem so much more vast), but it checks out (SI units):
p = 1e5
l = 38.6e9 * 1.61
A = 0.27871
R_m = 8.3141
M_CO2 = 12 + 16 * 2
R = R_m / (M_CO2 / 1000)
T = 273.15
V = l * A
m = p * V / (R * T)
f"{m:_}"
'33_558_455_134.769554'
The article is trying to "sell" the technology for two use cases, Mars and climate change mitigation on Earth.
For Mars, the process being inefficient, expensive, slow etc. isn't necessarily a big hurdle as it competes with shipping fuel all the way from Earth, while on Earth, it has to compete with a lot of easily available alternatives.
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?
Removing CO2 from the atmosphere ("direct air capture") is currently extremely expensive and inefficient, compared to e.g. getting it from some other industrial process or the exhaust from a fossil fueled plant. And you still end up having to ship the fuel which isn't trivial.
Nuclear power is currently more expensive per kWh than renewables. This could potentially change if we were to build many identical plants, which would be viable with this strategy. By building it somewhere far from civilization, lower safety standards could also become acceptable, lowering cost further.
But in order for this to pay off, you'd need an absolutely massive investment, and I suspect nobody wants to take that risk. Building 100 nuclear power plants will be cheaper than building one per plant but still more expensive in absolute numbers, and each plant is already a many-billion project. So for this to work, you'd likely need someone to commit hundreds of billions, and most likely all upfront/at the same time to actually reap the cost benefits for the nuclear plants. And the technology to actually make use of the power isn't there yet.
OTOH, with solar and wind, you can build a plant at basically any scale. A lot of small projects is much easier to make happen than one absolutely gargantuan one.
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.
> 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.
Why would they plug them in the evening though? If you're using the car, you're likely to be parking it at a place with a high car density (e.g. a large parking garage or an employer's parking lot), where chargers can be deployed cheaply.
If you have a short commute, you might also not care how fully charged your car is as long as it is enough. So you may specify that you want a state of charge of 50-80% at the end of the day, and the grid can decide when to charge your car. It won't be enough to smooth out all the fluctuations in renewable generation, but it surely will help.
10 million cars (~20% of the cars existing in Germany) attempting to charge is at least 10 GW of load that can be shed when necessary, and significantly more than that in load that you can sink when there is excess power (I'm assuming each car needs to charge e.g. 10 kWh over 10 hours). Wikipedia says the total Regelleistung (operating reserve?) in Germany is 12.5 GW (7 GW in one direction, 5.5 in the other) and that this is responsible for 40% of the cost of the grid fees.
Hourly priced electricity will be the future. Solar is creating this huge abundance of power during the day and electric cars are basically a huge grid of batteries. Since you are not using your car for the majority of the day and usually not during the middle of the day where peak solar kicks in, you can just plug your car in every time you leave it parked and then a charge controller sits and does nothing until power prices drop to the expected lowest price before charging. With some kind of fail safe where they charge anyway if no expected low occurred.
But another problem is that road construction itself is a huge cause of greenhouse gas emissions and isn't solved at all by electric cars. Only fewer and lighter cars would make things better. Personally I think electric scooters could replace a fair bit of car travel. The little sit down ones are sufficient to get you around for most trips and carry a bags worth of stuff.
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...
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Wow. I didn't realize that this is such a huge space. I thought Climeworks was basically the only company that actually has a working product already.
Is there a way to invest into the space through some form of managed fund? I have no way of evaluating the economics of any of the companies, but would like to park some of my money by investing in this sector (both hoping for an at-least-comparable-to-market return and wanting to support the development of the technology, while being OK with accepting extra risk - basically, I'm willing to donate to carbon capture and sequestration in the form of accepting a worse point than other investments on the risk/reward curve).
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?
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.
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.
Thank you, whenever these articles come out, people forget CO2 IS the lower energy state and while these catalysts can help, you still need energy to supply the H2...which requires you to burn coal/gas which makes CO2. It's not like there's a "CO2 always increases with every reaction" law like the 2nd law of thermo, but it isn't easy otherwise we'd all be doing that as it would be a hell lot easier to do that than the other things we need to do to combat climate change.
Burning organic anything makes water and CO2, amongst the most stable (read lower energy) chemicals in the world. If you want to break one of those up, you need to increase entropy some other way, and unless we're talking solar, wind, or nuclear energy, you're going to have to make more water and CO2 (burn more coal) to do it.
While that's a pretty expensive way of carbon capture, it does seem to work.
The question is of course how much energy it costs. It's probably quite a lot. Meaning that turning CO2 into methane is probably not a very efficient process. I.e. not a great use of clean energy.
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.
There are applications, particularly in certain modes of transporation, in which electrification is difficult. Batteries are heavy and large. Extension cords can only be made so long.
Even in a world in which heavier-than-air flight is sharply curtailed, there's still an exeptionally strong case to be made for marine transport as the most efficient mode huamns have ever developed, in moving mass a given distance with a given energy input (ton-miles/gallon or tonne-km/litre as you prefer).
Large, long-distance, high-capacity aircraft will require some sort of liquid fuel. Hydrocarbons have high density by both volume and mass, are well-understood, are remarkably non-toxic and non-volatile (for fuels), and have excellent handling and storage characteristics.
Marine shipping has similar constraints. Wind might re-emerge as a partial contributor. Solar might aid in auxiliary electrical systems. But a big slow marine deisel or turbine remains a hugely efficient prime mover. Solid fuels (e.g., pelletised wood waste) is an option, but is still strongly inferior to liquid fuels.
Even for rail, electrification of heavy freight is a challenge, all the more so with elevation gain and loss, and when travelling far from infrastructure. Yes, much European freight rail is electrified, but it operates at a much smaller scale and through far more developed regions than US and Canadian railways. The need to electrify an entire route also poses challenges (though rail does somewhat lend itself to incremental enhancement).
Electric rocketry is a whole 'nother challenge. Very long extension cords, maybe? Is Musk working on those?
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.
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.
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.
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.
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:
I'm using it to mean somebody who studies the technologies in the field. It would include both analysts and those who are actively performing research in industry and academia.
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.
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.
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.
In my naive mind, Methane seems like the it could be a good candidate for removal from atmosphere: If you could just get it to react with oxygen, it turns into water and the much less harmful CO2, so you don't have to sequester anything, and the reaction is exothermic i.e. it already "wants to happen"... we would "only" need an effective yet cheap catalyst to make it happen at low temperatures.
"the collective contribution of [SF6] and similar man-made halogenated gases has reached about 10 percent as of year 2020". But reading more closely, it seems the SF6 by itself is much less. The rest, I guess, must be CFCs and HFCs.
Those 10% are almost all CFC, then the next largest component is HCFCs and then HFCs, where SF6 is included. On the graph subtitle it's explained that SF6 is about 13% of the HFCs component.
Anyway, that's a large change from the last data I've found.
Do you suggest releasing a catalyst into atmosphere? It may be dangerous, people tend to release methane, kids sometimes injure themselves by "catalysing" reaction of methane with oxygen by a flame source just for fun of watching flame farts. It would be unfortunate if these flame farts happened spontaneously as a sort of an embarassing social accident.
I was thinking more of pumping air across a surface coated with a catalyst. Although a releasable catalyst would also be an interesting option. Not sure if flame farts would be a hindrance or a feature.
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.
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.
I’m looking forward to seeing the new chemical solar cells that take the carbon from carbon dioxide and place it into polymer chains of molecules that can be used as a fuel source or maybe material for 3D printing.
I'd much rather have it as a building material... baby steps I guess. The reason is, it's unlikely to be burned about put back into the atmosphere if someone is living in it.
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.
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)
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.
No, this isn't the case at all. I attended UCSC (ucsc.edu), and then UCSF (ucsf.edu) and was a postdoc at UCB (berkeley.edu). They are fairly integrated in a lot of ways. The term itself "Berkeley" can be used in context so that people can tell you mean the University, not the city. That's rarer for the other schools.
Also, Berkeley was the first real UC campus.
I think Berkeley has its own bare domain because their name was registered before the UC naming conventions were established. I'm pretty sure it was the first or second name registered. https://bind9.readthedocs.io/en/v9_16_5/history.html
Not sure of that, though- in the old HOSTS.TXT predating DNS, UC Berkeley was called UCB, and the server ucbvax became ucbvax.berkeley.edu.
I think it's funny now they teach classes at Berkeley about stuff (DNS, nuclear energy) and the research was done just 30-70 years ago right on the same spot!
They are more separate than University of Cincinnati is. If someone in California asks what college you go to, you don't say "UC"....you say "UC Berkeley" (or "Cal") or "UCLA" or the like. But you simply say "UC" if you are in Ohio and go to Univ of Cincinnati.
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.
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.
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.
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.
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.
Millions of tons of ammonia are produced every year. It is the favored refrigerant in industrial sites, such as warehouse-sized freezers. We have most of a century's experience handling ammonia in such quantities.
But ammonia is probably a better choice for fueling trains and ships than for aircraft.
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.
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.
Low mass density means you can't keep the LH2 in wing tanks. Inboard tankage might be unwise. Slinging tanks under the wings, alongside the engines, minimizes plumbing. It might seem like that would add a lot of drag, but aerodynamics is a very unintuitive science.
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..
Aluminum is supposed to be pretty tolerant of extra protons in its matrix. You might passivate the surface to be electropositive, to repel the ends of the H2 molecules as they try to weasel into the gaps. Liquified hydrogen is anyway much less mobile than gaseous hydrogen, and when used at atmospheric pressure, nothing is trying to force the molecules in.
Gaseous H2 at the extreme pressure people try to use is a much greater nuisance.
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?
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
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.
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 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).
When you switch a 11 year ICE car with an electric, yes, you would generate a 11 year-old ICE car. If priced low enough, somebody will pick it up and use it for a few years, since the purchase price, compared to a new electric car, is lower than the (worse fuel economy + higher maintenance costs) figure.
But, unless gasoline and diesel drastically drop in price, you are running towards an economic wall, since it's exactly people from Africa and former soviet territories that are the most sensitive to fuel economy and high maintenance costs. Meanwhile, electrics drastically drop in price, since they simpler and cheaper to produce.
The extra few years European cars will see in Africa is just the long tail of the ICE car in Europe, not some fundamental shift. If those would not be available, Africans would purchase cheap new Chinese ICE or other low cost brands. A visit to Eastern Europe will convince you that some 50% of cars are newly purchased cheap brands like Dacia-Renault, Mitsubishi Colt, Chevrolet Spark, often stripped down versions made specifically for these markets and priced at something like 10.000€.
These will have an even lower life expectancy than the typical 20-40.000€ western car, and will be in need for replacing.
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)
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.
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/documen...
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.
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.
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.
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.
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.
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.
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.
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.
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.
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?
> 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.
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.
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.
> 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!
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.
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.
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...
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.
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.
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