> We could start pulling more CO2 out of the atmosphere than we put in, and at that point we'd be pretty confident things won't get worse for the climate.
How much of the atmospheric CO2 can you actually capture with stations at ground level? I assume this isn't critical since I haven't seen anyone propose a Tower of Babel of carbon capture machines, but I'm not sure why it isn't.
>We could start pulling more CO2 out of the atmosphere than we put in, and at that point we'd be pretty confident things won't get worse for the climate.
Not sure that would be terribly efficient to pull CO2 out of the atmosphere to pump through this setup.
Would be fine for many other reasons though.
I wonder how it behaves with "non clean" CO2 sources. Like say at the output of a coal fired PowerStation.
>Unless you have zero access to point sources, point source capture will always be more "Environmentally Friendly" than atmospheric carbon capture.
Ideally we'll get to a point where every CO2 point source either stops being a point source, already has a mechanism for capturing the emissions, or can't economically accommodate carbon capture for some other reason (airplanes, probably).
At that point we might still have too much CO2 in the atmosphere. We'd have to figure out some way to get it out, whether that's by manufacturing hydrocarbons, planting trees, something else, or all of the above.
> we could use plants to put CO2 into easily stored liquid fuel that's largely compatible with existing infrastructure
Are you suggesting we spend resources to get CO2 out of the air and then burn them, releasing it again? We could capture it again (which is easier when there is a high concentration, such as at the exhaust of any such plant), but that seems like double the effort. You probably have a reason why this is a good idea or you wouldn't be suggesting it, so I'm interested to hear your thoughts on it.
> The key really is the CO2 flux rate which wind provides.
Indeed. This brings us to the issue of volumes. A useful carbon capture plant needs to capture at least 100 000 tons of CO2 per year (then we need "just" ~ 10 000 such plants). This means each of these minimal plants has to process an air volume of 250 billion cubic meters of air per year. At an air speed of 1 m/s (you can't flow too fast or there is no time for reaction), and assuming a wildly optimistic 50% capture from the filtered air, you need a reaction area of over 15 000 square meters.
Mind you, that's the area of the membrane which processes air. Add the auxiliary stuff around it, you can add at least another factor of 100 to the area, so each of your 10 000 plants have to be 1.5x the maximum planned size of the Tesla Gigafactory. And we're being optimistic.
> carbon sequestration [will] likely require energy
Yes, but that doesn't mean we won't need it.
Take air planes. We can't just put batteries in there: too low energy density or something (I'm no physicist, but they won't fly very far is what I gather). But by capturing the CO2 (at exhaust, or atmospherically) that they put out, we can have both airplanes and a stable climate -- assuming it's all done right.
Who wants to have a wind turbine in their back yard? A nuclear power plant? Who lives near that hydro plant in the middle of nowhere? We could instead capture CO2 away from people if power is cheap, before sending the rest down a slightly lossy transmission path.
Driving regular passenger vehicles electrically is definitely less energy intensive than capturing the GHGs that a combustion engine produces, so it would obviously be counter-productive to use capture technology for those sorts of things. But we can use it for other things like chemical processes that produce a GHG as a byproduct where it's hard to capture (new buildings using concrete, for example) or when we don't have the technology to get rid of the emissions.
Right now, the quickest wins are from emission reduction. This capture technology is something we need to have ready for the next phase of keeping our natural habitat stable.
> Capturing carbon is a valuable step, but only as part of a process that net removes it from the atmosphere.
The IPCC, the IEA, and a boatload of scientists disagree. We cannot prevent catastrophic global warming without doing the type of CCS you describe as useless. Sure, we also want to be doing stuff that's net carbon negative, but that's a long way into the future.
And CCS from power generation is only one aspect. CCS from cement plants, steel furnaces etc. is another thing we need - those processes will inherently emit large amounts of CO2 even if electric power is 100% renewable.
Finally, when it comes to capture from air, I think stuff like "biomass -> syngas -> water shift -> separation of CO2 captured and stored, H2 produced for energy" is much more likely to be successful, because you can make it net CO2 negative and it produces something valuable as a byproduct. Capture from air is a whole 'nother matter, starting from a very low CO2 partial pressure and thus very inefficient.
> Until now, technologies being developed to capture CO2 from the air have been constrained by the cost of capture and the ability to harvest the gas at scale. The technology being deployed by SKH addresses both issues, bringing the cost of capture comfortably below $100 per metric ton at scale — the lowest in the industry — making it both commercial and impactful toward reducing global warming.
So, What would it take to commercialize this technology?
> Using CO2 from an industrial point source is more efficient; however, it has potential legislative issues when it comes to certification of sustainable fuels, emission certificate trading... it's a fairly complicated topic.
I can imagine! Considering lots of the co2 in air has fossil fuel origin, not putting the co2 capturing at a high volume co2 source seems rather dim. Regulators gonna regulate!
Maybe site the direct air capture in the middle of a german industrial city with coal plants all around...
>Wow its been 3 years, where did all these great tech go?
The fundamental problem with carbon capture is that 1) carbon comprises a tiny fraction of Air, and 2) requires energy input in some form. This means whatever methodology you use, will require you to expand energy to move huge volumes of air to remove a small number of particles (i.e. ~400 particles of Carbon, for 1 million Air particles).
> From what I know, carbon capture over a field is not exactly a solved problem.
Doesn't appear to be capture-capture over a field. Instead:
> Navigator’s project would have laid pipelines across five US states—South Dakota, Nebraska, Minnesota, Iowa, and Illinois—to collect CO2 from ethanol and fertilizer plants and pipe the gas to an underground storage site in Illinois.
Sounds like they were planning on point-source capture, which is generally a good bit more efficient than open-air capture.
If it were carbon-capture over a field, then it'd probably be under the category of "open-air capture" -- which is technically easy to do (as capture in general is; we've had CO2-capture technology since the 1930's), just more costly (since it's less thermodynamically efficient to capture from a low-concentration source like the atmosphere, relative to capture from a high-concentration source like the flue-gas from a plant).
Capturing CO2 from point-sources (like the flue-gas from plants) tends to be relatively efficient, which seems to work out better both economically and environmentally.
> David Friedberg argued on the all in podcast that a 25 square-mile areal of these would be enough to capture all CO2 currently in the atmosphere.
I felt like napkin mathing it, and even a cursory check completely obliterates that claim. Adding 1 ppm (volumetrically) of CO2 to the atmosphere is about 2 Gt of CO2, and we're at about 400 ppm. Carbon is 27% by mass. Monocrystalline diamond is 3.5 g/cm3. This makes a prism with the specified base 1km high. Talk about a ring.
The linked article seems to indicate that the researchers are also much more conservative with their claims than Freidberg, and state their technology is about 8x more efficient at capture than corn. Very cool, but nowhere near that sort of magnitude, as 8x that area would be only a fraction of the farmland in the continental US alone (by a factor of 1000).
> its sustainable, because the fuel is being created from CO2 captured from the air by photosynthesis
An essential detail: the CO2 would have been back in the atmosphere soon, regardless of its use. We need less CO2 in the atmosphere, regardless of who, what, when, or how it got there or how it's removed.
The method of capture doesn't matter. Atmospheric carbon capture devices would be just as good, if they worked efficiently.
If you capture CO2 in a way that would keep it from the atmosphere long-term, then releasing it again is obviously not a good idea.
If you grow corn, you capture CO2. But the corn will soon die and (if I understand correctly) release the CO2 again, so you might as well use the corn for your fuel and release the CO2 that way.
However: If you plant a field with corn for fuel instead of with longer term carbon capture options (e.g., certain types of trees), it seems like a loss. It's better than digging up CO2 that's already stored long term (fossil fuels) and adding it to the atmosphere, but that's not good enough. We need to get CO2 out of the atmosphere.
How much of the atmospheric CO2 can you actually capture with stations at ground level? I assume this isn't critical since I haven't seen anyone propose a Tower of Babel of carbon capture machines, but I'm not sure why it isn't.
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