Does carbon capture make sense?

[TheVat]

Reading in the paper about the opening of the world's biggest carbon capture plant, I had to wonder if this expensive tech-heavy approach was the most efficent way to reduce atmospheric CO2.

https://www.washingtonpost.com/climate-solutions/2024/05/09/climeworks-mammoth-carbon-capture/

Quote

The entire process runs on Iceland’s plentiful geothermal energy, so powering the machines doesn’t produce more carbon emissions. Outside scientists confirmed that the Climeworks Orca project and an earlier pilot plant really do remove carbon while producing very few emissions in a 2021 analysis published in Nature.

Climeworks then sells offsets based on that captured carbon. It doesn’t publicly say how much it charges its big corporate customers, including Microsoft, Shopify and Stripe, for the service — but it offers regular people carbon removal subscriptions at a price of $1,500 per metric ton of carbon removed. More than 20,000 people have signed up, according to the company’s website.

“The only people purchasing Climeworks removals at this point are very wealthy individuals or very wealthy companies that are … paying a lot of money to bring down the costs of what they see as a potential future industry,” said Rudy Kahsar, manager of carbon dioxide removal at the clean energy think tank RMI...

Wouldn't using Iceland's "plentiful goethermal" to power homes and vehicles etc be a more efficient way to keep carbon out of the air?  The most efficient carbon capture, it seems to me, is not putting carbon in the air in the first place, i.e. promote green energy and agriculture and industry.  Rather than letting big carbon polluters "greenwash" their industries, i.e. validate their continuing business as usual by purchasing carbon offsets.  And there's also forest restorations, which if done properly provide a longterm, eventually self-maintaining system of carbon capture and fixation.  I think people are blinded by technophilia so they forget the Earth has many natural carbon filters that can be restored and augmented.  (from an engineering perspective, forests also do double-duty, in both grabbing/fixing carbon and also rendering heat-stressed areas especially in the tropics more habitable, less prone to lethal wet-bulb temperature heat waves.)

[swansont]

You can do more than one thing. Preventing carbon emissions doesn’t remove carbon that’s already in the system.

Given the state of things, a multi-pronged approach seems prudent.

[MigL]

The Earth is a closed system.
All the carbon was already here before atmospheric CO₂ levels started to rise.
I didn't come from anywhere else, and it won't be going anywhere else.
Any reduction will come from 'locking it' in other forms, such as in solution or rocky compounds, or even plant and animal life that in a few million years become fossil fuels.

The problem we currently have is that the rate of release of carbon into the atmosphere is much greater than the natural processes that re-capture it; adding to, or speeding up, those processes, can help just as much as reducing the rate of release. 

[exchemist]

6 hours ago, TheVat said:

Reading in the paper about the opening of the world's biggest carbon capture plant, I had to wonder if this expensive tech-heavy approach was the most efficent way to reduce atmospheric CO2.

https://www.washingtonpost.com/climate-solutions/2024/05/09/climeworks-mammoth-carbon-capture/

Wouldn't using Iceland's "plentiful goethermal" to power homes and vehicles etc be a more efficient way to keep carbon out of the air?  The most efficient carbon capture, it seems to me, is not putting carbon in the air in the first place, i.e. promote green energy and agriculture and industry.  Rather than letting big carbon polluters "greenwash" their industries, i.e. validate their continuing business as usual by purchasing carbon offsets.  And there's also forest restorations, which if done properly provide a longterm, eventually self-maintaining system of carbon capture and fixation.  I think people are blinded by technophilia so they forget the Earth has many natural carbon filters that can be restored and augmented.  (from an engineering perspective, forests also do double-duty, in both grabbing/fixing carbon and also rendering heat-stressed areas especially in the tropics more habitable, less prone to lethal wet-bulb temperature heat waves.)

Icelanders already do use geothermal power, a lot, for electricity and space heating. 

My attitude to this is that the human race seems to be currently in a "brainstorming" phase, in which many rival approaches are being tried simultaneously, without much judgement as to which are best. I think that is the right approach, as so many of these technologies are new that we can't yet be sure which will be the ones we take forward and which will prove to be dead ends. I have in mind it is not just a matter of apparent technical superiority. There are human factors, such as social acceptance and geopolitics, to take into account as well. Betamax was technically superior to VHS. 

Regarding "greenwashing", this is an easy accusation to make but the fact is we will need fossil fuel for quite a few years yet as we make the transition. It seems to me carbon offset trading has a role to play while we do this. I don't buy the notion that they are all about continuing business as usual.  

[swansont]

59 minutes ago, exchemist said:

My attitude to this is that the human race seems to be currently in a "brainstorming" phase, in which many rival approaches are being tried simultaneously, without much judgement as to which are best. I think that is the right approach, as so many of these technologies are new that we can't yet be sure which will be the ones we take forward and which will prove to be dead ends. I have in mind it is not just a matter of apparent technical superiority. There are human factors, such as social acceptance and geopolitics, to take into account as well. Betamax was technically superior to VHS.

Are they rivals, though? VHS and beta were rivals because you would only use one, but if two approaches can be used in different situations they are complementary, at least to some extent. If approaches have strengths and weaknesses you can tailor your system to what works best in your location or situation.

[exchemist]

7 hours ago, swansont said:

Are they rivals, though? VHS and beta were rivals because you would only use one, but if two approaches can be used in different situations they are complementary, at least to some extent. If approaches have strengths and weaknesses you can tailor your system to what works best in your location or situation.

Sure, I just meant it as an example of where factors other than technical superiority have determined the technology chosen.

Thinking about it more, I suppose @TheVat's point may not actually be a technical one really, but more an economic one, viz. why spend limited resources on a "sticking plaster" technology, rather than on those that address the problem at source?  But again my view would be the amount of resources is not really fixed. Some governments, corporations/societies may be willing to devote funds and effort to a "sticking plaster"  technology that they would not be willing to expend on, say hydrogen, or nuclear energy, in which case I would say let them do that then, at least to see how far it can be made to work, while others pursue the more fundamental solutions. 

[TheVat]

6 hours ago, exchemist said:

Thinking about it more, I suppose @TheVat's point may not actually be a technical one really, but more an economic one, viz. why spend limited resources on a "sticking plaster" technology, rather than on those that address the problem at source?  But again my view would be the amount of resources is not really fixed. Some governments, corporations/societies may be willing to devote funds and effort to a "sticking plaster"  technology that they would not be willing to expend on, say hydrogen, or nuclear energy, in which case I would say let them do that then, at least to see how far it can be made to work, while others pursue the more fundamental solutions. 

That was where I was poking at the idea.  You make a fair point - as they say, "politics is the art of the possible."

And I was also looking at the technical side.  I.e. if my country has 20 gigawatts accessible from geothermal, is it more efficient to use that all for power (plus export, say, as hydrogen or filled superbatteries), or to use some for air capture?  If the former keeps 50 million tons out of the air, and the latter only keeps out 30 million tons, then the scrubber would have to remove >20 million tons just to break even on the process.  So one should look at break even points on these expensive scrubbing systems.  Also compare them, in longterm cost, to forest plantings (or seagrass meadow plantings, say) which remove and fix equal amounts of carbon.  

 

17 hours ago, swansont said:

You can do more than one thing. Preventing carbon emissions doesn’t remove carbon that’s already in the system.

Hence my question as to planting forests, seagrass, boosting phyto in the sea, etc and how they compare in overall carbon removal.  The C capture approach strikes me as the fancy boutique approach - looks cool, captures lots of publicity and hype - but I wonder how it really makes much dent.  

[MigL]

7 hours ago, exchemist said:

rather than on those that address the problem at source?

I think you are ignoring part of the 'problem', or the source.

The burning of fossil fuels is not the problem, as it was done since the 'invention' of fire, with no adverse consequences ( other than cigarette smoking 😄 ). Even forest fires, while releasing carbon into the atmosphere, make way for new arboreal growth that recaptures that carbon, and maintains equilibrium.
It was only during the last couple of hundred years ( industrialization ) that the rate of man-made release of atmospheric CO₂, surpassed nature's ability to re-capture and sequester that carbon into living organisms, creating increasing CO₂ atmospheric levels, and a shifting equilibrium.

The problem is then twofold; the rate of release has increased, and the rate of re-capture hasn't kept pace.
The solutions ( simplistically ) are, reduce the former, or increase the latter.

[swansont]

1 hour ago, TheVat said:

And I was also looking at the technical side.  I.e. if my country has 20 gigawatts accessible from geothermal, is it more efficient to use that all for power (plus export, say, as hydrogen or filled superbatteries), or to use some for air capture? 

I don’t think this is a zero-sum situation. 

[TheVat]

2 hours ago, MigL said:

The problem is then twofold; the rate of release has increased, and the rate of re-capture hasn't kept pace.
The solutions ( simplistically ) are, reduce the former, or increase the latter.

So let me drill down into this question (haha).  I am Thorvald Vatsson, and I have one billion dollars* to reduce CO2, without leaving Iceland to do this.  What will give me the highest overall CO2 reduction per gigawatt - build a fancy air scrubber, build geothermal generation capacity for my country (or export), or some optimal combination of the two?  (planting a fast-growing forest is off the table, this being Iceland)  I know there are some "depends" issues here.  But I would hope there could be some way to determine a break even point, in a very rough way.  

 

*US dollars, not those nearly worthless Canadian ones

[MigL]

If looking at it in terms of economics, of course it is cheaper to just stop doing what is causing the increase in CO₂ levels.
What about when you take into account the economic losses from such an approach ?

That's the beauty of trees; it doesn't matter where you plant them.
If you use the geothermal energy generated in Iceland to provide irrigation to arid African savannah, you could grow a forest that captures CO₂ from the whole atmosphere.
The trees don't need to be in Iceland.

[swansont]

3 hours ago, MigL said:

I think you are ignoring part of the 'problem', or the source.

The burning of fossil fuels is not the problem, as it was done since the 'invention' of fire, with no adverse consequences ( other than cigarette smoking 😄 ). Even forest fires, while releasing carbon into the atmosphere, make way for new arboreal growth that recaptures that carbon, and maintains equilibrium.
It was only during the last couple of hundred years ( industrialization ) that the rate of man-made release of atmospheric CO₂, surpassed nature's ability to re-capture and sequester that carbon into living organisms, creating increasing CO₂ atmospheric levels, and a shifting equilibrium.

The problem is then twofold; the rate of release has increased, and the rate of re-capture hasn't kept pace.
The solutions ( simplistically ) are, reduce the former, or increase the latter.

Forest fires are not burning fossil fuels. Forests will grow again, so any CO2 released is offset by growth somewhere. 

Fossil fuels represent sequestered carbon, stored over many millions of years but released over a much shorter time, and much faster than natural processes could store it again. It is because we were burning fossil fuels that these rates aren’t the same. It didn’t start with the invention of fire - it started with the large-scale burning of sequestered carbon. Most of the time before the industrial era back for hundreds of thousands of years, the CO2 levels were lower than at the outset of the industrial era

 

[MigL]

Burning fossil fuels releases carbon stored for millions of years.
Burning a tree releases carbon that was sequestered for tens or hundreds of years.
Wood was once a tree, a living organism; it may not be 'fossilized', but it is no longer living.

You're making essentially the same point.
It is the rates of release compared to re-capture that have changed dramatically and are throwing the equilibrium off-balance,
Increasing the rate of re-capture, or sequestration, can, in theory, be just as effective as reducing the rate of release, in controlling amounts of atmospheric CO₂.
Possibly not as easily achievable, but if Iceland has a workable method, I see no reason to dismiss it.

[zapatos]

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Edited May 11 by zapatos

[TheVat]

11 hours ago, zapatos said:

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[zapatos]

I was pointing out that Iceland already gets near 100% of their electricity from green sources and still has geothermal capacity to spare. Thus they may as well use that capacity to scrub the air. Then I noticed others said similar things and I didn't want to be redundant.