Subsurface storage vaults for biogenic carbon is likely the most energy and cost efficient way to sequester carbon at this time. Wet vaults for biochar and dry vaults for carbon casting blocks are promising. These methods can help mitigate embodied emissions related to low carbon energy sources such as renewables and batteries. Also, it can buy time for concrete and steel to decarbonization while clean infrastructure scales. These carbon capture methods are modular, deployable across wide geographies, biomass agnostic, and have low energy inputs in comparison to DAC and point source capture. The trick will be avoiding land use diversion while maximizing photosynthesis across all not agricultural lands. This method can also be useful for carbon currency creation which I believe is a precursor for atmospheric GHG stabilization.
Efficient method to capture carbon dioxide from the atmosphere
321–330 of 349 posts
Re: Efficient method to capture carbon dioxide from the atmosphere
#322Earlier quoted context omitted.
Plants capture CO2 from photo synthesis at huge scale. That seems like a great way to capture it at a higher concentration. We’d need to handle the organic matter before natural decomposition, but quite doable.
It’s even less energy efficient gathering up plant matter at this scale and permanently sequestering it, than getting it from the atmosphere. At least with the current technology required to harvest, move and process it. It’s why biomass is still a relatively niche ‘carbon offset’ technique. It is also highly space inefficient and time consuming to grow and store (sequester). Even if we converted all US cropland (and…
Extraction of the resource is not free. But with advances in solar panels and battery technology, the economic arguments for much fossil fuel use is fast disappearing. We were never going to make difficult decisions for the sakes of our grandchildren - we're much too selfish for that - but as renewables put more money in our pockets, we might just make the right decisions. Even if it is for the wrong reasons.
Re: Efficient method to capture carbon dioxide from the atmosphere
#323Earlier quoted context omitted.
It’s even less energy efficient gathering up plant matter at this scale and permanently sequestering it, than getting it from the atmosphere. At least with the current technology required to harvest, move and process it. It’s why biomass is still a relatively niche ‘carbon offset’ technique. It is also highly space inefficient and time consuming to grow and store (sequester). Even if we converted all US cropland (and…
Extraction of the resource is not free. But with advances in solar panels and battery technology, the economic arguments for much fossil fuel use is fast disappearing. We were never going to make difficult decisions for the sakes of our grandchildren - we're much too selfish for that - but as renewables put more money in our pockets, we might just make the right decisions. Even if it is for the wrong reasons.
The issue is more than just being carbon neutral now, it’s paying back the energy released from the initial burning of the fossil fuel.
So it’s more like 2-3x non-fossil kWh for every 1x current fossil fuel kWh energy usage.
It’s a huge problem.
Re: Efficient method to capture carbon dioxide from the atmosphere
#324Well, instead of repeating myself manually, I'll paste in a comment of mine here from a past discussion on carbon capture: It's easy to forget why there is a bit of a challenge to getting C02 out of the air: there's so little of it, comparatively. In order, air is, broadly, made up of the following: Nitrogen: %78.084 Oxygen: %20.946 Argon: %00.934 CO2: %00.042 The stuff is essentially beyond a rounding error - it rea…
I get what you're saying, but couldn't this be used in a place with high concentrations of CO2, like factory chimneys?
Yes, but these scrubbers need vast amounts of energy. Most of which emit carbon. We simply need to curb emissions. With the possible exception of basaltic rock weathering, DAC is not practical. Large DAC projects fail to reach forecasts, even when these forecasts for plants costing tens of millions of dollars only aim to extract global emissions of two or three seconds.
Re: Efficient method to capture carbon dioxide from the atmosphere
#325Earlier quoted context omitted.
I get what you're saying, but couldn't this be used in a place with high concentrations of CO2, like factory chimneys?
Yes, but these scrubbers need vast amounts of energy. Most of which emit carbon. We simply need to curb emissions. With the possible exception of basaltic rock weathering, DAC is not practical. Large DAC projects fail to reach forecasts, even when these forecasts for plants costing tens of millions of dollars only aim to extract global emissions of two or three seconds.
That same money could replace a lot more emissions with other sources of energy. How much solar and batteries does it buy? It’s always struck me as a moonshot project for people who don’t understand thermodynamics.
You could probably unstir the cream from the coffee with an elaborate chemical processing system costing more than what thousands of coffee makers and dairy cows cost.
The only CO2 removal project I’ve seen that seems like it might be viable is ocean fertilization. That’s not a thermodynamic free lunch. You’re letting solar powered microorganisms do it. But it needs to be studied and monitored to make sure it doesn’t ruin ocean ecosystems and that enough of the carbon actually does get sequestered to make it actually worthwhile.
Re: Efficient method to capture carbon dioxide from the atmosphere
#326Earlier quoted context omitted.
Then you’ve built poorly. That’s not the wood’s fault
No? Buildings don't last forever.
No, but when built right, log cabins have lasted 100+ years easily. Furniture has lasted that long as well. If you keep it dry, it will last longer than you, your children, and your grandkids. Easily. At that point it is more forever than you
Re: Efficient method to capture carbon dioxide from the atmosphere
#327Earlier quoted context omitted.
Also more fundamentally it's always going to be more efficient to not produce CO2 than to unproduce it. Ok maybe in a small number of circumstances there's no other option (e.g. planes), but mostly you're far better off spending your energy making solar, wind, batteries, heat pumps, insulation etc.
It's hard to put my finger on why, but that's a really weird way to frame the situation. For one thing, most of us don't control any CO₂ production we can turn off. Also, even if/when we finally produced our last CO₂ molecule, the excess CO₂ will last for many centuries, and we really should get it back to lower levels. With good capture tech, you can keep keep doing some important CO₂ producing activities. Sure, it…
> Sure, it seems very unfeasible with current technology, but that is bound to improve as you work on it.
That not a good logical argument as there's no guarantee that every technology can be improved enough to be better than the alternatives. e.g. Steam engine tech is bound to improve as you work on it, but it's not going to be as efficient/useful as an internal combustion engine.
History is littered with examples of tech that has been surpassed by better ideas, so the lesson to learn is to optimise the best current solution. In this instance, the best (most efficient, practical) solution is to stop emitting so much CO2 rather than a long bet that capture tech will ever be feasible - with atmospheric concentrations being so low, the scale required makes it a non-starter.
Re: Efficient method to capture carbon dioxide from the atmosphere
#328Earlier quoted context omitted.
So then, is it really the CO2 that produces the cognitive impairment, or is the CO2 here just the proxy value that we are measuring, and the real reason for the cognitive impairment is low oxygen?
Nitrogen also causes cognitive impairment. It is essentially a very weak anesthetic. If you can replace all of the nitrogen in your breathing gas with helium then you'll probably gain the equivalent of a couple IQ points (although obviously that isn't generally practical).
Nitrogen narcosis is especially relevant to divers. Recreational SCUBA diving is usually limited to around 30m depth and some divers will start noticing effects (basically like getting drunk) near that depth when using air in the tanks. This is why different mixtures (e.g. trimix) are used at increased depths, though there are other important effects of breathing air at pressure such as oxygen toxicity.
Re: Efficient method to capture carbon dioxide from the atmosphere
#329Earlier quoted context omitted.
You can actually capture CO2 from sea water thereby reducing ocean acidification and improving its capability to continue as our planets biggest CO2 sink.
Well here's the thing - there's quite a lot of water out there too. How long and how many terawatts of power do you think it'll take to suck a significant fraction of the earth's seawater through a capture facility?
It is actually amazingly energy efficient as the electrolysis produces H2 at one electrode and consumes it at the other. Hence, very little additional energy is needed. As offshore wind produces a lot of surplus energy at night - this could be used. So far it was possible to capture approx. 92% of the CO2 in the amount of seawater handled. Could likely be increased to 94% - 96%.
Re: Efficient method to capture carbon dioxide from the atmosphere
#330Earlier quoted context omitted.
I think it’s little appreciated that high CO2 levels cause cognitive impairment, and with the same amount of (often very poor) air exchange, higher outdoor concentrations can push indoor spaces to levels that cause impaired cognition and poor sleep. I’ve already been seeing this in my home, and will often open windows even when cold just to keep co2 levels reasonable. One solution that can help is an external air hea…
Ok this sounds like BS, what kind of sensor is being used to get such readings? What do you use?
I'm using a desktop CO2 meter, they're cheap and accurate, and can be tested by just putting them outdoors and confirming that they read known outdoor levels correctly. What you are saying is not unlike doubting that it's possible to measure temperature with a thermometer- CO2 measurement is extremely reliable, cheap, and mature technology.
This is the meter I am using, costs $39, and is a calibrated instrument with +/- 3% accuracy. I have an academic colleague that uses these same devices for scientific research on plant metabolism, and they are highly accurate and are optionally self calibrating just by opening a window or putting them outdoors.
https://www.co2meter.com/collections/indoor-air-quality/prod...