Is Capturing Carbon from the Air Practical?

http://www.technologyreview.com/news/531346/can-sucking-co2-out-of-the-atmosphere-really-work/

by mrfusion • 12 years ago

30 60 12 years ago

oe• 12 years ago

It surprising how little plans for fixing global warming are discussed. Most of the discussion deals with preventing global warming by reducing carbon dioxide emissions, which is of course something we need to do.

But if we agree that there's already too much CO2 in the air, why not figure out ways to remove it or otherwise prevent further damage?

Klapaucius4• 12 years ago

The CO2 content of the exhaust from a coal-fired power plant is (fortunately) many orders of magnitude higher than what's found in the atmosphere. It would be much cheaper to capture it at the source. But even that is still considered too expensive, which is part of the reason we don't see many large-scale carbon capture and storage operations popping up.

But there are some encouraging news from Canada these days: http://blogs.scientificamerican.com/observations/2014/10/07/...

mrfusion8• 12 years ago

I wonder why he can't just sell carbon credits to fund it? Is that not a large market?

mrfusion8• 12 years ago

I'm curious why this was down voted? I meant it as a legitimate question. I don't know much about carbon credits but I'd imagine anyone taking CO2 out of the atmosphere would be able to sell them?

mrfusion8• 12 years ago

How about the idea of building a giant "freezer" in the coldest part of Antarctica and sublimating the CO2 out of the air? Some places already hit that temperature naturally [1]

[1] http://news.nationalgeographic.com/news/2013/12/131210-colde...

maxerickson2• 12 years ago

It isn't a high enough proportion of the atmosphere to be an effective strategy (also, you mean precipitate out of the air; sublimation is the process where a solid becomes a gas).

We talked about it before:

https://news.ycombinator.com/item?id=7174246

I linked this article, which discusses somebody actually testing the partial pressure explanation in a lab freezer capable of maintaining those low temperatures:

http://wattsupwiththat.com/2009/06/13/results-lab-experiment...

mrfusion8• 12 years ago

Wow, you're right. We already had this conversation :-)

Ok, so let's assume you're right about this. According to that chart, at a partial pressure of 0.0004 atmospheres the precipitation temperature would be around -140C. And nature is still doing a lot of the work of getting us to that point at -93C.

So the question becomes is cooling air from -93C to -140C an efficient means to capture CO2?

tokenadult• 12 years ago

This statement from the article cautions us that the economic incentives (which are also reasonably well described in the article) so far aren't promoting technical fixes like the one proposed by the inventors: "None of the world’s thousands of coal plants have been outfitted for full-scale capture of their carbon pollution. And if it isn’t economical for use in power plants, with their concentrated source of carbon dioxide, the prospects of capturing it out of the air seem dim to many experts. 'There’s really little chance that you could capture CO2 from ambient air more cheaply than from a coal plant, where the flue gas is 300 times more concentrated,' says Robert Socolow, director of the Princeton Environment Institute and co-director of the university’s carbon mitigation initiative."

When I hear about plans to capture CO2, I wonder immediately about whether those plans will help enough if other gases (for example, methane) play a significant role in greenhouse effects. We may have to sequester more than one gas, in more than one way, to role back the accumulation of greenhouse gases already in the atmosphere, if that is considered a desirable worldwide goal.

mrfusion8• 12 years ago

That's true, I've heard that methane is much worse than CO2. I wonder if methane can be pull out of the air?

chriswarbo• 12 years ago

Since methane is worse than CO2, it's actually better WRT the greenhouse effect to burn it and produce CO2 + water. Water's also a potent greenhouse effect contributor, but the atmosphere's already saturated with it, so the excess will just rain back down.

Here's an interesting site found through Google:

http://www.bbc.co.uk/climate/evidence/methane.shtml

ThisIBereave• 12 years ago

As the poster above mentioned, Methane has a greater immediate impact, but it only stays in the atmosphere "for 11-12 years"[1], making it a relatively short term problem. CO2 stays in the atmosphere for "approximately 100 years"[2].

1: http://www.bbc.co.uk/climate/evidence/methane.shtml 2: http://www.bbc.co.uk/climate/evidence/carbon_dioxide.shtml

startupfounder• 12 years ago

“Once capturing carbon from the air is profitable, people acting in their own self-interest will make it happen,” says Chichilnisky.

This is the key to the entire article.

The conversation shouldn't be around the practicality of capturing carbon from the air, the conversation should be what is the most profitable way to reduce carbon in our air either through not putting it in the air in the first place or removing it cheaply after the fact.

This demands a more robust marketplace beyond CO2 for soda and oil wells.

"The idea is to first sell carbon dioxide to niche markets, such as oil-well recovery, to eventually create bigger ones, like using catalysts to make fuels in processes that are driven by solar energy."

danielweber5• 12 years ago

I'm a bit worried that, because of weird locally-smart but globally-dumb incentives, we might see people consuming 1 KWh to capture a unit of CO2, but the generation of 1 KWh puts more than 1 unit of CO2 into the atmosphere.

I'd like to see the numbers.

EDIT:

The worst coal emits 2.18 pounds of CO2 per KWh.[1] As little as 917Kwh of energy puts a ton of CO2 into the air.

They say that can do it for "$15 to $50 a ton". How much of that is energy costs? $50 buys 500KWh, so even if you used coal to operate it, it would net remove carbon from the air.

I'd still like to see a plant using nuclear energy to change CO2 into fossil fuel, though.

[1] http://www.eia.gov/tools/faqs/faq.cfm?id=74&t=11

ChuckMcM• 12 years ago

That would be an effective way to arbitrage the cost of carbon which isn't externalized on the power plant. However I don't think it would come to that. I'm surprised the SRI effort isn't recovering the CO2 (they claim to be venting it). After all if they really do think they can get $100 a ton for it and make it at $50 a ton, that would at least offset some of their research costs.

danbruc• 12 years ago

The conversation shouldn't be around the practicality of capturing carbon from the air, the conversation should be what is the most profitable way [...]

No, money should play no role. It is obviously easier to reduce CO2 emissions if it is profitable but there is - at least in theory - nothing that prevents governments from just demanding the reduction even if it will increase the price of products or services. In practice you will of course have to deal with businesses just moving to where nobody cares and the like but that does still not mean that money should be an important factor.

hackuser• 12 years ago

Reducing carbon emissions does not affect profitability because emitters don't pay for them; they are 'externalities', if I remember my economics correctly. Put the cost on their balance sheets and reducing carbon emissions will become profitable.

If you dump a ton of solid toxic sludge in my back yard, ruining my back yard, and you will pay to clean it up. Dump a ton of gaseous toxic sludge in the atmosphere, contributing to a global catastrophe, and you don't pay a dime.

Ignoring the morality of it, it seems like simple responsibility: Why is everyone else suffering from and paying to clean up their mess? Sea walls, forest fires, water shortages, etc. etc. Taxpayers are paying to clean up the mess made by the emitters.

danielweber5• 12 years ago

Because neither party wants to write off the coal states.

There is still a Coasean way out: offer those states money to not burn their coal.

Klapaucius4• 12 years ago

"This demands a more robust marketplace beyond CO2 for soda and oil wells."

The only permanent solution is sequestering the carbon deep underground (depleted oil/gas fields or saline aquifers). Most CO2 "utilization" cases (including production of biofuels) merely delay the inevitable release of the gas into the atmosphere.

Sequestering CO2 for the sake of sequestering it does not pay though. In order for this to make sense, a carbon tax would likely have to be imposed (it worked in Norway, where Statoil has stored excess CO2 geologically for almost two decades now at the Sleipner field).

prestonbriggs• 12 years ago

Plant more trees?

erikpukinskis• 12 years ago

Trees convert co2 into cellulose, until they die and rot, releasing the co2.

ph0rque2• 12 years ago

Is Capturing Carbon from the Air Practical?

You mean like... trees?

mattmaroon• 12 years ago

They're not really practical. Land is expensive.

kefka• 12 years ago

Really? You just said that?

Undeveloped land is a treasure trove for biology. We use it for food, medicine, natural resources among other things.

And money means nothing if we cannot breathe.

rosser2• 12 years ago

Unfortunately, the only way trees make money is when they're cut down. Apparently, the only way we're going to embark on any sort of program to stave off environmental catastrophe is if someone can make a buck off it — and until then, we'll just keep doing what we're doing, consequences be damned.

Priorities, huh?

ankitml2• 12 years ago

Unfortunate is not the fact that trees make money only when they are cut down. Unfortunate is the way we measure money value. Trees , forests and entire natural biodiversity ecosystem gives us so much value which is not counted in money. This (http://www.cbd.int/incentives/teeb/) is the scientific project which aims to build a database for measuring economic value of biodiversity.

ph0rque2• 12 years ago

Most (maybe all?) deciduous trees can be cut down to the stump without dying: they'll just grow back. This art is ancient, called coppicing.

Fuzzwah• 12 years ago

Some people will pay you to keep your trees.

https://news.google.com/news?q=Norway+to+Pay+Liberia+to+Stop...

rogerbinns• 12 years ago

Capturing carbon from the air is extremely practical - plants do it using solar power. What is this technological approach trying to achieve, versus just using plants?

rqebmm• 12 years ago

They're trying to then store and commecercialize the captured C02. This approach will, ideally, create a marketable product out of reducing emissions, while those greedy plants just steal it to feed themselves

danielweber5• 12 years ago

It takes plants a long time to do that, and so far they aren't keeping up with mankind's increased CO2 output. (Although parts of Canada are greening, so there are negative feedback cycles in the carbon loop. Dunno how long that would take.)

baq• 12 years ago

the problem with they way plants do it is efficiency. the whole process is like 1% efficient.

DennisP2• 12 years ago

Much larger amount of carbon absorbed for a given land area, and no worries that it'll go back into the air later when plants rot or burn.

avn2109• 12 years ago

> "Is Capturing Carbon from the Air Practical?"

There are already widely-available solar-powered redundant distributed systems that do this while producing valuable outputs. Around here we call it the forest (tm).

rthomas66• 12 years ago

Apparently trees are carbon neutral or even net emitters of carbon once they're mature, so this is only true for young forests.

Edit: I am wrong in the case of old growth forests. After a bit of googling, they are still net carbon capturers. For an individual tree, I'm more right. And in both cases, young trees/forests absorb more carbon in a given span of time than old trees/forests.

blhack• 12 years ago

I think you're missing the point. The forest is literally stored carbon. All of those trees, plants, animals, etc. are all made out of carbon that has been sucked out of the air and converted into biomatter.

(Unless I'm really, really misunderstanding something)

ankitml2• 12 years ago

Not sure what you mean, Forests are net emitters when they burn, or they are cut, or their top soil which stores carbon is removed. Forests by just being forests do not emit carbon just like that.

bkeroack• 12 years ago

We have machines for doing this. They're called trees. Let's stop cutting them down.

rthomas66• 12 years ago

Trees are carbon neutral or even net emitters of carbon once they're mature, so a better solution would be to frequently cut them down and then replant them.

Edit: I am wrong in the case of old growth forests. After a bit of googling, they are still net carbon capturers. But not as much as young forests.

maxerickson2• 12 years ago

It's vaguely interesting that, in the U.S., the entities best equipped to do this are the federal and state governments. Private landowners tend to manage their forests for profit and don't have any cantankerous recreational users to mollify before they arrange a sale (well, other than themselves).

readerrrr• 12 years ago

They are? How?

My perspective is: most of the mass of the three comes from the air, and trees are weighed in tonnes. When they die the carbon goes in the ground( as long as they aren't burned ).

jdmichal• 12 years ago

We don't really have to stop cutting them down. In fact, not having lumber would have a far, far bigger effect on the economy than creating an entirely new technology to scrub CO2. We do, however, need to plant more trees when we do cut them down.

gregorkas• 12 years ago

But if we build awesome factories that will gradually reduce the global CO2 levels, they will be useless when they do their job too good. :)

jgh• 12 years ago

That's ok, we can always burn more coal.

Animats• 12 years ago

If this can be made reasonably small, it could supply CO2 for carbonated drinks in fast food outlets. Many fast food outlets have a CO2 fill port out back, where the tank truck connects to refill the tanks. That's not going to make a big dent in CO2 emissions, but it might be a viable product.

Klapaucius4• 12 years ago

Even if done at an industrial scale, it would serve no purpose from a climate perspective. Adding CO2 to a drink does nothing to get rid of it. Once the drink is consumed, the CO2 is right back out there. You only delay the release into the atmosphere a tiny bit.

danielweber5• 12 years ago

Depends. What was the source of CO2 that you displaced? If they were also capturing it as the exhaust from another industrial process, then you're right. On the margin, though, there might be people producing CO2 just to have the CO2.

mrfusion8• 12 years ago

For another CO2 capture idea, how much CO2 could be captured if a billionaire bought up all of the lumber on the market and buried it?

bduerst• 12 years ago

That's not very sustainable.

What if we engineer nano machines that pulled CO2 out of the air, and used sunlight to convert it to chemical energy?

These molecular machines could even use that chemical energy to self-reproduce, or produce human-consumable foods and fibers.

danielweber5• 12 years ago

More straightforward: buy up exclusive coal rights, and then leave it in the ground.

Is Capturing Carbon from the Air Practical?

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