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Robotic 'trees' can turn CO2 into concrete

engadget.com

21–30 of 125 posts

Re: Robotic 'trees' can turn CO2 into concrete

#21
post #6

Earlier quoted context omitted.

If the purpose is carbon sequestration, you'll have to include the cost of storing that wood. Indefinitely. Won't be cheap.

You'll also need to store it in a way that does not release the wood's CO2 back to the atmosphere by biodegradation.

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

Re: Robotic 'trees' can turn CO2 into concrete

#22
post #8

Earlier quoted context omitted.

You'll also need to store it in a way that does not release the wood's CO2 back to the atmosphere by biodegradation.

If you turn it into charcoal you keep most of the carbon locked up in a non-biodegradable form.

And you can add it to soil where it works wonderfully at increasing biomass, reducing water runoff and increasing the number and variety of microorganisms in the soil, sequestering more carbon.

http://en.wikipedia.org/wiki/Terra_preta

Re: Robotic 'trees' can turn CO2 into concrete

#23
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 think all these comments about wood eventually releasing the carbon back into the atmosphere are missing the point. We don't need to capture it forever, we just need to get the ratio between carbon output and input under control in the next couple of decades. That should give us enough time to come up with longer term and sustainable ways of our planet... until we encounter the next problem, and so on.

"Solutions" don't have to be perfect forever. They just need to work long enough till better solutions are discovered.

Re: Robotic 'trees' can turn CO2 into concrete

#24
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?

Well, according to Energy and Civilization forest stores an average of 1 watt per square meter in burnable wood. Wood burning is pretty carbon intensive as energy goes so I imagine that each square meter of forest, if the fallen trees are buried deep underground, could offset several watts of internal combustion engine use.

Re: Robotic 'trees' can turn CO2 into concrete

#25
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 think all these comments about wood eventually releasing the carbon back into the atmosphere are missing the point. We don't need to capture it forever, we just need to get the ratio between carbon output and input under control in the next couple of decades. That should give us enough time to come up with longer term and sustainable ways of our planet... until we encounter the next problem, and so on. "Solutions"…

You could also just bury it. That’s effectively putting coal back into the ground.

Re: Robotic 'trees' can turn CO2 into concrete

#26
post #6

Earlier quoted context omitted.

If the purpose is carbon sequestration, you'll have to include the cost of storing that wood. Indefinitely. Won't be cheap.

Doesn’t a forest tie up the carbon in live trees? A mature forest will be more or less carbon neural but a certain amount of carbon won’t be available to the atmosphere.

The trees will die eventually. The problem is that we've released a lot of CO2 from trees that died millions of years ago.[0]

If you want to get that out of the atmosphere, it's not good enough to grow trees today because in 50-100 years (or whenever a tree dies) you're right back where we are today.

[0] https://www.nationalgeographic.com/science/phenomena/2016/01...

Re: Robotic 'trees' can turn CO2 into concrete

#28

Earlier quoted context omitted.

I think all these comments about wood eventually releasing the carbon back into the atmosphere are missing the point. We don't need to capture it forever, we just need to get the ratio between carbon output and input under control in the next couple of decades. That should give us enough time to come up with longer term and sustainable ways of our planet... until we encounter the next problem, and so on. "Solutions"…

You could also just bury it. That’s effectively putting coal back into the ground.

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

Re: Robotic 'trees' can turn CO2 into concrete

#29
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?

There's got to be something that grows faster, and is easier to sequestrate, than trees. Bamboo, maybe? Seaweed? Algae? Dry it off in salt pans and dump it in the deep, cold ocean? That's just dumping more carbon into one of our natural sinks, I think, rather than trying to create a new artificial sink. Even just using it as fertilizer has got to be an improvement over using inorganic fertilizers.

Iron fertilization

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

Re: Robotic 'trees' can turn CO2 into concrete

#30
post #12
post #8

Earlier quoted context omitted.

If you turn it into charcoal you keep most of the carbon locked up in a non-biodegradable form.

If you use it to build homes you provide shelter for more people.

We need to unburn roughly as much coal as we've burned. We're talking about hundreds of billions of tons. You could probably plaster the whole surface of the planet with homes and not have used enough wood.
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