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Robotic 'trees' can turn CO2 into concrete

engadget.com

71–80 of 125 posts

Re: Robotic 'trees' can turn CO2 into concrete

#71
post #67

Earlier quoted context omitted.

Wood is not dense enough for this to be cost effective.

You could burn it – the ash from burning a tree takes up only a fraction of the original volume.

Don’t know if this is sarcasm, but burning the wood releases most of the carbon dioxide back into the air. The ash is just the unburnt carbon residue and other leftovers.

Re: Robotic 'trees' can turn CO2 into concrete

#72
post #71
post #67

Earlier quoted context omitted.

You could burn it – the ash from burning a tree takes up only a fraction of the original volume.

Don’t know if this is sarcasm, but burning the wood releases most of the carbon dioxide back into the air. The ash is just the unburnt carbon residue and other leftovers.

Yes, it was a joke. Sorry for that.

Re: Robotic 'trees' can turn CO2 into concrete

#74
post #68

I have a hard time taking an article seriously who uses an image of water vapor coming off nuclear cooling towers as an example of carbon emissions from energy production.

Those sort of cooling towers aren't just for nuclear power. They're the most efficient way of cooling anything, unless you're next to a river. Judging from the railway and storage around it, I think that's a coal plant.

Yes. But whatever, they're still cooling towers. No CO2 comes from there, just water vapor. But many, I suspect, think that they're squat smokestacks.

Re: Robotic 'trees' can turn CO2 into concrete

#75
In order for non-biological CO2 capture to be workable, we'll need to ramp up energy production maybe 5-10 fold. Without releasing substantially more CO2. Covering the Sahara and US Southwest with PV (and wind farms, where appropriate) might make the nut. But if we manage to dig too huge a climate change hole, we'll likely need more like 20-100 fold more energy. Maybe fusion, or massive orbital solar arrays.

Re: Robotic 'trees' can turn CO2 into concrete

#76

Seriously, everyone suggestions a crackpot idea for sequestering carbon should do the basic arithmetic for how much annual human emissions are (40 billion metric tons). I like https://blogs.scientificamerican.com/life-unbounded/the-craz... for the perspective it offers: current human CO2 emissions are equivalent to the entire continent of Africa being covered in coniferous forest and burning to the ground in forest f…

How is that possible? Surely the volume of fossil fuels being burnt isn't remotely comprable to the volume of that forest.

Re: Robotic 'trees' can turn CO2 into concrete

#77

Seriously, everyone suggestions a crackpot idea for sequestering carbon should do the basic arithmetic for how much annual human emissions are (40 billion metric tons). I like https://blogs.scientificamerican.com/life-unbounded/the-craz... for the perspective it offers: current human CO2 emissions are equivalent to the entire continent of Africa being covered in coniferous forest and burning to the ground in forest f…

> should do the basic arithmetic

North America is sitting at around 6.5Gt p/a, three [experimental] plants sequester 0.55Mt p/a. You'd need 35000 plants in just North America. 216000 plants world-wide.

Re: Robotic 'trees' can turn CO2 into concrete

#79

Earlier quoted context omitted.

I read it again, twice. That is exactly what they’re doing. Their starting material is CO2-source cement, not some natural “rock”. Counterexamples are substantially more helpful than downvotes.

It seems they're not replacing the quicklime, but the gravel. The left column is confusing, the right column is better. > A rock particle is coated with our synthetic limestone, forming a carbon-sequestering coating that is 44% by mass CO2. That's where the CO2 goes, not in curing the CaO

But where does the Ca come from? Obviously not from limestone...

Re: Robotic 'trees' can turn CO2 into concrete

#80

Seriously, everyone suggestions a crackpot idea for sequestering carbon should do the basic arithmetic for how much annual human emissions are (40 billion metric tons). I like https://blogs.scientificamerican.com/life-unbounded/the-craz... for the perspective it offers: current human CO2 emissions are equivalent to the entire continent of Africa being covered in coniferous forest and burning to the ground in forest f…

How is that possible? Surely the volume of fossil fuels being burnt isn't remotely comprable to the volume of that forest.

I don't know if the math is correct, but oil and coal are far more energy dense than wood which may account for the discrepancy.
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