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Robotic 'trees' can turn CO2 into concrete

engadget.com

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Re: Robotic 'trees' can turn CO2 into concrete

#111

Post by thinkcontext »

milcron wrote: post #88
thinkcontext wrote: post #28

Earlier quoted context omitted.

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

If a woodpile isn't dense enough, then surely building homes and furniture out of wood isn't dense enough either. Can you think of a better way to store carbon!

Not very dense compared to the cost of digging a big hole in the ground with Caterpillars and the number of truck loads of pellets you would need to bring in. This is all assuming that just covering the wood over with dirt is enough to keep it sequestered, a big pile of biomass could start emitting methane.

> Can you think of a better way to store carbon!

BECCS like they referred to in the article.

Re: Robotic 'trees' can turn CO2 into concrete

#112

Post by discreteevent »

Cthulhu_ wrote: post #41
rbanffy wrote: post #21

Earlier quoted context omitted.

Wood used in construction seems to degrade very slowly. I've lived in houses whose the floor alone was a couple hundred years old.

That's in dry conditions though, it'd probably be gone by now if there wasn't a roof.

Scorched timber can last a hundred years. I have seen a cabin from 1740 made of timber from trees that were scorched in a forest fire but remained alive.

Re: Robotic 'trees' can turn CO2 into concrete

#113

Post by dexen »

OscarCunningham wrote: post #76
throwaway5752 wrote: post #64

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.

Living trees are only about 15...18% carbon by weight. [1] Other greenery is probably even less, given that significant proportion of trees' mass is in the trunk as cellulose (some 50% of it)[2], which is about 44% carbon.

On the other hand, CO2 is only about 27% carbon (also by weight). [3]

[1] https://web.extension.illinois.edu/askextension/thisQuestion...

[2] https://www.britannica.com/science/cellulose, https://en.wikipedia.org/wiki/Cellulose

[3] mostly O16, mostly C12, 12 / (12+16+16)

Re: Robotic 'trees' can turn CO2 into concrete

#114

Post by mirimir »

roryisok wrote: post #101
mirimir wrote: post #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.

I read some encouraging recent reports that a Sahara PV project would not only generate about 5 times the energy requirements of civilization, it would also increase rainfall in the Sahara and probably lead to greening. Meanwhile offshore wind in the North Atlantic could also supply multiples of the energy we need. These combined would be sufficient to free us from fossil fuels, future proof us against the increase r…

Yes, thanks :) That's what I was thinking of, and ought to have mentioned it. It was on HN within the past week or so.

And yes, that could be a great outcome. But sadly enough, I suspect that the situation will get a lot worse before the US, at least, does anything substantial.

Re: Robotic 'trees' can turn CO2 into concrete

#115

Post by xupybd »

TangoTrotFox wrote: post #63
stronglikedan wrote: post #58

Earlier quoted context omitted.

I guess you're being downvoted for pedantry, because your statements are accurate.

More like sensationalism. I don't downvote, but the comment is absolutely ridiculous. Even the absolute worst case scenarios for climate change are not species ending events with current technology. And we have many decades ahead of us yet where can solve the problem with future technology yielding a negligible overall impact. That said even the mild effects are undesirable and seeing how close we'll come to the wors…

I don’t actually think climate change will kill off humanity.

I’m very optimistic about our ability to solve this and also think the sensationalism is out of control.

But even in that worse case the planet is far from dead.

Re: Robotic 'trees' can turn CO2 into concrete

#116

Post by xupybd »

stronglikedan wrote: post #69
TangoTrotFox wrote: post #63

Earlier quoted context omitted.

More like sensationalism. I don't downvote, but the comment is absolutely ridiculous. Even the absolute worst case scenarios for climate change are not species ending events with current technology. And we have many decades ahead of us yet where can solve the problem with future technology yielding a negligible overall impact. That said even the mild effects are undesirable and seeing how close we'll come to the wors…

You seem to have read a lot more into the parent comment than I did. I read it as a simple rebuttal to the articles opening statement saying climate change is killing the planet. While it's impossible for climate change to kill the planet, it is possible to render it too hazardous for humans if left unchecked.

That is all I was trying to say

Re: Robotic 'trees' can turn CO2 into concrete

#117

Post by [deleted] »

08-15 wrote: post #108
throwaway5752 wrote: post #91

Earlier quoted context omitted.

I'm sarcastically saying that we had proposals for a cap and trade system that would have mitigated it but it was destroyed for political reasons.

Obviously. I'm non-sarcastically saying that cap-and-trade won't work, because any meaningful cap is unrealistic to achieve. The political reason is: We want cheap energy. The politically acceptable choices boil down to burning coal or gas, no matter how bureaucracy is layered on top.

[deleted]

Re: Robotic 'trees' can turn CO2 into concrete

#118

Post by taejo »

abbe_k wrote: post #45
taejo wrote: post #13

Earlier quoted context omitted.

Building houses is great, but if you're growing the trees in order to sequestrate carbon , you'd better be reasonably sure a decent proportion of the wood doesn't release it's carbon within the next fifty years. I don't live in a country where wood is a major building material, but I'm imagining that most wood that goes into building gets discarded within a few decades and ends up decomposing or being burnt.

If treated and maintained right it can last hundreds of years. So this is not really an issue and if you replace it with new wood it will still store carbon.

> if you replace it with new wood it will still store carbon.

Good point, although you need to be sure you aren't counting the wood you replace it with as more carbon storage. Every wooden house essentially provides a fixed amount of carbon storage, no matter how much of it is replaced, and only as long as it stands.

Re: Robotic 'trees' can turn CO2 into concrete

#119

Post by sambeau »

6nf wrote: post #2

Every time one of these articles come up I wonder about the price per tonne of CO2 removed by simply growing wood and not burning it. I'm not really sure what that price is, but it seems to be around $20-$40 per tonne? Does anyone have a more accurate number?

I've often wondered (half jokingly) if a solution to CO2 in the atmosphere is to grow trees, chop them down and bury them in disused coal mines.

Re: Robotic 'trees' can turn CO2 into concrete

#120

Post by erikpukinskis »

dwighttk wrote: post #4
6nf wrote: post #2

Every time one of these articles come up I wonder about the price per tonne of CO2 removed by simply growing wood and not burning it. I'm not really sure what that price is, but it seems to be around $20-$40 per tonne? Does anyone have a more accurate number?

Rotting wood releases carbon dioxide too.

You don’t let it rot. You mill it, and scorch it. That will give you a couple hundred years of protection. Then you start stacking the timbers in a pyramid. As you add more and more layers to the pyramid, the bottom layers compress, eventually becoming totally uninhabitable by bugs and bacteria. Over time you end up with a giant pyramid made of coal, and possibly diamond. (haven’t done the math on how tall you have to stack coal to get diamond)
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