Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Efficient method to capture carbon dioxide from the atmosphere

helsinki.fi

Post reply on HN
Print view View original

331–340 of 349 posts

Re: Efficient method to capture carbon dioxide from the atmosphere

#331

Post by BurningFrog »

gsf_emergency_6 wrote: post #305
BurningFrog wrote: post #300

Earlier quoted context omitted.

Should every car owner personally optimize the CO₂ emissions of their car? I have definitely not argued against the laws of thermodynamics. I'm sorry, I don't even know what you're arguing for.

> With good capture tech, you can keep keep doing some important CO₂ producing activities. We're not asking people to stop breathing while there's no good DAC on the horizon, but I wonder what were the other important CO₂ producing activities you intend to do less of. The following isn't breaking the law of thermodynamics; just wilfully ignoring it.. Gemini: > To offset a single typical gasoline car's emissions (arou…

There are 3 or 4 laws of thermodynamics, and I can't figure out which one you might possibly be referring to.

I agree that current carbon capture tech is very inadequate, because very little effort has been put into it. How many orders of magnitude better it can get, we don't know until we try, but I don't see any fundamental reason it can't get good enough.

Once you have a solar powered capture machine park pumping CO₂ underground, it can keep working indefinitely at little cost.

> I wonder what were the other important CO₂ producing activities you intend to do less of.

All of them. This is well under way. I don't know how many decades it will take. But that's a separate problem.

The crucial thing to understand is that even if/when all CO₂ production has ended, the produced CO₂ won't disappear by itself for thousands of years!!

So you really need to actively remove it to get back to natural levels. Which is why I think carbon capture tech must be developed.

Re: Efficient method to capture carbon dioxide from the atmosphere

#332

Post by _yb2s »

ekianjo wrote: post #78
_yb2s wrote: post #67

Earlier 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…

> high CO2 levels cause cognitive impairment Sounds seriously unlikely. How would this work in practice, at the level of bodily functions?

Why would this be unlikely as a prior? High CO2 changes your blood chemistry and breathing rates. Different breathing rates have a well understood effects on lots of systems including sympathetic/parasympathetic activation. There is no reason to expect humans to be evolutionary adapted to CO2 levels that we couldn't have experienced historically.

Several other posters in here have posted peer reviewed studies replicating these effects, but personally I find individual direct experience with my own body to be massively more generally useful when making health decisions than studies in other people, or some known mechanism.

Re: Efficient method to capture carbon dioxide from the atmosphere

#333

Post by _yb2s »

ekianjo wrote: post #309
MathMonkeyMan wrote: post #83

Earlier quoted context omitted.

I don't know the mechanism, but: https://www.google.com/search?q=co2+cognitive+impairment

This has the hallmark of confounding factors. There is no way you can design a study to control for CO2 alone vs other trace contaminants in the air.

In that case it wouldn't matter much to an individual making personal decisions about their environment. Either way, an environment with enough outdoor air exchange to keep CO2 low would avoid these effects.

But hypothetically, what other trace contaminants would you expect to be so universally correlated with CO2 in different environments that they could account for repeatedly observing these effects in different studies? That seems implausible.

Re: Efficient method to capture carbon dioxide from the atmosphere

#334

Post by philipkglass »

Manuel_D wrote: post #293
8bitsrule wrote: post #290

Earlier quoted context omitted.

'Very small'?? Depends on your perspective. "The amount of CO2 removed from the atmosphere via photosynthesis from land plants is known as Terrestrial Gross Primary Production, or GPP. It represents the largest carbon exchange between land and atmosphere on the planet. GPP is typically cited in petagrams of carbon per year. One petagram equals 1 billion metric tons, which is roughly the amount of CO2 emitted each yea…

Man-made carbon emissions amount to over 40 billion metric tons annually, according to a quick Google search. Worldwide terrestrial plant carbon exchange amounts to less than 2.5% of the CO2 humans release, if plants take in 1 billion tons per year. From the perspective of averting climate change it is indeed very small.

The article linked by 8bitsrule says:

A team of scientists led by Cornell University, with support from the Department of Energy’s Oak Ridge National Laboratory, used new models and measurements to assess GPP from the land at 157 petagrams of carbon per year, up from an estimate of 120 petagrams established 40 years ago and currently used in most estimates of Earth’s carbon cycle.

Whether 157 billion tons or 120 billion tons, these numbers are large compared to anthropogenic releases. Of course most of this carbon is quickly cycled back out from land plants due to animals/bacteria/fungi consuming the biomass produced by land plants.

Re: Efficient method to capture carbon dioxide from the atmosphere

#335

Post by sfn42 »

cjbenedikt wrote: post #329
sfn42 wrote: post #30

Earlier quoted context omitted.

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%.

You're still ignoring the fact that there is an absolutely unfathomably insane amount of water on the planet.

The world's largest pump (according to a quick search) can pump 60,000 liters per second. The oceans contain over 1.3 billion cubic kilometers of water. One cubic kilometer is a trillion liters. It would take this pump - the largest pump in the world - 192 days to move one cubic kilometer of water.

Let's be charitable and say we can make a noticeable dent in ocean CO2 if we could only process 1% of the ocean's water per year. That's about 13 million cubic kilometers. Let's be generous and say one of these pumps can do 2 cubic kilometers a year even though it's a bit less. So we'd need 7.5 million of these pumps - and of course we'd also need each of them to be connected to a facility that's capable of processing all the water as quickly as the pump can supply it.

This is the problem with carbon capture. We can't build many/large enough capture facilities to make a difference.

Re: Efficient method to capture carbon dioxide from the atmosphere

#336

Post by Xss3 »

jmward01 wrote: post #278
rayiner wrote: post #230

Earlier quoted context omitted.

> The only solution we have is put less in the air in the first place That’s not a solution either, because the developing world is not going to stop increasing their CO2 output until they fully industrialize. They’re just not. Feel free to seek reductions where you can, but don’t think of it as a solution because it’s not. The technical problems with CO2 capture are far more solvable than the sociological problems w…

Actually, solar and other renewables are making it easy to skip legacy hydrocarbon based infrastructure and the 'developing world' (not the west) is snapping it up [1]. Additionally, the big problem countries aren't really the developing world. China is rapidly hitting its targets and other than a brief moment where they threw up a lot of coal fired generation to meet immediate demand it looks like they will very rap…

I wonder if we will see more DC grids. You can get a decent 5 - 20% efficiency improvement out of it as most end user devices are DC now.

Re: Efficient method to capture carbon dioxide from the atmosphere

#337

Post by crucialfelix »

rayiner wrote: post #256
crucialfelix wrote: post #250

Earlier quoted context omitted.

Developing world generally has a lot more sunlight, and now very cheap solar energy.

It's not cheaper when you factor in the batteries, the need for sophisticated electric grids, etc. China and India continue to build huge amounts of coal power. It's not because they're too stupid to buy the cheaper option.

> Solar panel imports will reduce fuel imports. The savings from avoiding diesel can repay the cost of a solar panel within six months in Nigeria, and even less in other countries. > The solar panels imported into Sierra Leone in the last 12 months, would generate electricity equivalent to 61% of the total reported 2023 electricity generation.

https://ember-energy.org/latest-insights/the-first-evidence-...

A lot of people simply dont have electricity. They don't have grids. Night comes, it's dark. People are buying solar panels to get electricity directly. Now they can recharge lights during the day.

> China and India continue to build huge amounts of coal power.

One factor here is finance: companies make more money building coal plants. Banks loan the money so they can make money. Solar isn't as lucrative. It's the cheapest source of energy.

Re: Efficient method to capture carbon dioxide from the atmosphere

#338

Post by michaelhoney »

jmward01 wrote: post #114

I am not against doing research in this area, please do, it is interesting and likely has many applications but global CO2 removal isn't one of them. Nothing proposed, including this, is within any orders of magnitude of a viable solution. The only solution we have is put less in the air in the first place. This tech looks interesting for transporting CO2 but that doesn't mean it sequesters it and even if sequestrati…

You are 100% right that we _should_ be focusing on reducing emissions, but the reason we would prefer to capture-and-sequester is... money. We make money by emitting C02, and it looks like we will also pay to have it captured again. Is this madness? Also yes.

Someone will make a trillion dollars out of this.

Re: Efficient method to capture carbon dioxide from the atmosphere

#339

Post by 8bitsrule »

adrianN wrote: post #297
8bitsrule wrote: post #290

Earlier quoted context omitted.

'Very small'?? Depends on your perspective. "The amount of CO2 removed from the atmosphere via photosynthesis from land plants is known as Terrestrial Gross Primary Production, or GPP. It represents the largest carbon exchange between land and atmosphere on the planet. GPP is typically cited in petagrams of carbon per year. One petagram equals 1 billion metric tons, which is roughly the amount of CO2 emitted each yea…

You still need to turn incredible amounts of biomass into charcoal or other stable forms of carbon to make a dent in atmospheric co2. It would take decades of hard work on gigantic scales to unburn and bury the fossil fuels we used.

That's the pay-off of our 150-year rush to monetize as much of the Earth's natural resources as possible -- while making stringent efforts to keep quiet knowledge - or suppress any efforts - to utilize the benefits of free solar energy.

Having polluted and despoiled much of the biosphere, of course we'll be donating our supposed wisdom and that hard work to the future generations that will enjoy the fruits of our labors and entreasurement.

Re: Efficient method to capture carbon dioxide from the atmosphere

#340

Post by gsf_emergency_6 »

BurningFrog wrote: post #331
gsf_emergency_6 wrote: post #305

Earlier quoted context omitted.

> With good capture tech, you can keep keep doing some important CO₂ producing activities. We're not asking people to stop breathing while there's no good DAC on the horizon, but I wonder what were the other important CO₂ producing activities you intend to do less of. The following isn't breaking the law of thermodynamics; just wilfully ignoring it.. Gemini: > To offset a single typical gasoline car's emissions (arou…

There are 3 or 4 laws of thermodynamics, and I can't figure out which one you might possibly be referring to. I agree that current carbon capture tech is very inadequate, because very little effort has been put into it. How many orders of magnitude better it can get, we don't know until we try, but I don't see any fundamental reason it can't get good enough. Once you have a solar powered capture machine park pumping…

If you think about it, 2nd law* is the most relevant one because, after all, CO2, being so stable, is one of homo sapiens "favourite" waste materials (partition function yada-yada)

How did plants evolve to use it as nutrients. Solar power. since humans don't need to make fuel from air these days, maybe all of that solar power should go into compute?

.. I'm not saying any laws are broken, just that there are much better (=more efficient, more promising) ways to reduce global warming, like

https://en.wikipedia.org/wiki/Passive_daytime_radiative_cool...

It already works now (no airquotes), except for DAC entrepreneurs who try to hoard attention without having paid their "attention dues" first.

*And the one humans like to ignore because there seems to be so much wiggle room

Post reply on HN