This is a cool idea, but it comes with a weird perverse incentive problem.
The authors estimate that a "CC CNF" power plant would produce $835 of electricity and over $225,000 of nanotubes from a single metric ton of methane. At this point, economically, this is no longer a power plant: it is a carbon nanotube factory that has the side-effect of producing power. And if nanotubes are so valuable, the power generation part starts to look like a distraction: why not just pull the electricity off the grid and convert methane/CO2/coal/oil straight into nanotubes for less cost and complexity?
So really, this doesn't seem to be about power plants, so much as a (maybe) cheap way to make nanotubes from carbon. If we can incentivize people to make useful products out of all that CO2 just floating in the atmosphere, then maybe, just _maybe_, we can start fixing the mess we made.
Right.. 1MT of methane leads to 0.75MT of carbon nanotubes valued at $225,000 -- an implicit price of $300,000/MT for CNTs.. EPA estimates that energy production releases about 8.1 million metric tons of methane annually, so if we convert 1% of the methane to CNTs, we'd have about 61,000 metric tons of carbon nanotubes to dispose of. What happens to the price if you dump 60,000 tons of a previously rare product on the market? What happens if you up the requirement to 10% and you have 600,000MT of nanotubes?
But where would the market go when carbon nanotubes and fibers move from exotic and expensive materials to "cheaper than aluminum". It could displace a lot of aluminum and steel.
Interesting possibilities, right? Imagine automobiles, bridges, buildings all built with carbon frames at a cost potentially far lower than current aluminum or steel, and also consuming a fraction of the energy to produce?
they would be used to reinforce concrete, plastics and whatever you could think of. as long as they're bound into the material in a way that's not easily released into the air or ground we should be fine.
The big problem, as I commented further down, is that the volumes of CO2 we need to capture absolutely dwarf the production volumes of essentially any product.
I just crunched the numbers, and if everything sold on Amazon was made from 100% captured CO2, it would still account for significantly less than 1% of what we need to capture, transport and store.
I don't think "sold on amazon" is a good benchmark when it comes to bulk mass. Construction materials might be a better choice. Concrete production is measured in Gt/a.
And of course we also need to reduce carbon emissions, capture is not a singular solution, but it may help during the transition to renewables where we still need gas plants.
Well concrete already uses lime, which is calcium carbonate (the original carbon sink). Maybe skip the carbon fiber use case all together and figure out a way to effectively produce artificial calcium carbonate.
And potentially creating a heap of new problems seems as there is a good deal of research which suggests that carbon nanotubes are genotoxic and carcinogenic.
Disposal of it could be just as costly as Asbestos with just as adverse side effects.
I fully understand that some people getting cancer is less of a problem than our planet becoming uninhabitable, but it most certainly can't be swept under the carpet and forgotten about.
> If we can incentivize people to make useful products out of all that CO2 just floating in the atmosphere, then maybe, just _maybe_, we can start fixing the mess we made.
Is this really a shorter path than just planting more trees, which is both cheap and extremely low maintenance?
We only have so much land to plant trees on. (Which is very quickly shrinking due to urban and agricultural pressure.)
The current amount of carbon sequestered in all of the world's forests is ~600 giga-tonnes.
If we stopped all of our carbon emissions today, and tried to roll back to pre-industrial CO2 levels, we'd need to sequester ~270 giga-tonnes of carbon. Losing that much agricultural land is unrealistic - expensive as they are, it would be much less painful to switch our entire energy economy to renewables.
> We only have so much land to plant trees on. (Which is very quickly shrinking due to urban and agricultural pressure.)
The obvious solution being to increase carbon/biomass per hectare in our urban and agricultural land.
>Losing that much agricultural land is unrealistic
Losing it, yes. But replacing it with agroforestry and soil building no-tillage agriculture would increase the food supply (mainly since bare dirt monoculture fields are so abysmal at utilizing sunlight compared to healthy engineered ecosystems). Similar story with replacing corn-fed CAFOs and compacted ranch land with sylvopasture and MIRG (managed intensive rotational grazing).
If it sounds unrealistic to replace our whole food system with something else, remember that there is no alternative. The modern industrial food system isn't a viable replacement for itself. That's all the word "unsustainable" means: it's not an ethical judgement, but a logistic certainty.
Spreading a few million tons of powdered iron ore over the southern ocean will capture vast quantities of carbon in the resulting plankton boom, will feed enormous schools of fish and precipitate to the ocean bottom where it will lay captured for millennia.
You don't need vast forests to capture carbon. You need one soon to be retired 30 year old panamax ship. A cargo hold full of ore (~50$/ton + 20$ powdering), and a on-board pump/aerator.
...and a willingness to accept any unintended or unforeseen consequences.
The burden of proof that "iron fertilization" (or any other geo-engineering technique) will even result in a net reduction in anthropogenic climate change — leaving entirely aside, you know, not actually being harmful — is on the people who want to do it. As much as CO₂, &c, is a problem that begs for something to be done, I don't think that's been adequately demonstrated yet.
What does that mean ? What would be "adequately demonstrated" for rosser would be wildly risky for fooman, and overly risk averse for ageofwant.
ageofwant is satisfied that given the limited trials so far and the Russ George "experiment", which by all indications were wildly successful, large scale ocean seeding trials is called for.
Given the risks associated with doing nothing, and the relative low cost of a large trial, it would be silly, nay morally indefensible not to.
I really want you to be right on this. Way more than I want me to be right.
But the consequences of being wrong on some of the things being suggested to combat climate change could be tremendous, and in some cases even worse than the problem they're being used to solve.
I don't know where the balance that needs to be struck lies, but I'm pretty sure it's somewhere on the far side of:
"Welp, sounds good to me!" — some dude on the internets
This is certainly true, but we are talking about absolutely staggering amounts of land. As it stands now, ~30% of our planet's landmasses are covered in forest. Also, some kinds of forest are much better at sequestering carbon - specifically, the tropical rainforests that are being cut and burnt in the tropics.
Re-forestation is part of the solution, but it's no panacea.
urban pressure is negligible on a global scale--this is actually freeing up vast areas of land for use as people migrate to denser living.
Agriculture is a harder angle to attack; however, trees are excellent use of space: they store carbon for a period of time, they require low maintenance, they oxygenate the atmosphere, they can be planted cheaply and densely; harvesting them allows use of stored carbon (build with wood! Paper. Etc); they can be planted in areas that are typically not friendly to agriculture (eg mountains, places with extreme cold, etc). For the space we do have, there isn't much reason NOT to plant trees.
I would be interested in a comparison between different types of dense vegetation; eg trees vs grass vs moss vs algae, etc etc.
Well if you imagine planting trees in vast numbers where there are none today, that will have a rather dramatic environmental impact on any species currently living there. Possibly leading to endangerment or extinctions. A price worth paying, perhaps, but others won't agree.
Lots of land used to be forested and only was deforested due to human activities in the first place. Take the mediterranean coast[0] or iceland[1] for example.
Dense planting means the canopy can prevent rain getting to the ground and the trees take a lot of the water that does get to the ground which means aquifers are not replenished.
The dry ground and dry trees pose an increased fire risk. Burning the tree releases any captured carbon, and a bunch of smoke.
New forests crowd out and change existing eco systems, meaning many animals are lost to the area.
I highly doubt temperate or even tropical forest canopies will prevent water from reaching ground level. Gravity does not work that way.
Trees shade soil reducing evaporation levels. Trees also significantly reduce surface winds further reducing evaporation. Yes trees do potentially use more water which is exactly what you want, what is the purpose of full aquifers flowing into the sea ?
In Australia removal of trees has lead to increased salinity levels affecting 2 Million hectares (In WA alone) of arable land degrading vast swathes of it rendering it unusable for both modern agriculture and pre-agricultural "natural" use. This is precisely because the trees kept the high-salinity water table below surface root levels.
You can bury trees as a stable carbon sink. The real is storing CO2 is not economical and any other cheap form of carbon could be burned. So really the best option is to leave it in the ground in the first place.
Scale, 10 Giga Tons of carbon per year. 36 Gigatons of CO2.
7 billion people. Wood is not 100% carbon and a wood house is ~30 tons of wood. But, there is not a house per person and people don't build new houses every few years.
Don't worry. This whole "making stuff from CO2" business is completely stupid anyway.
I say this because the volumes of CO2 capture necessary for the two degree scenario (that we all just committed to in Paris) are so beyond the scale of almost anything we manufacture that it's not even funny.
We're talking thousands of Hoover dams full of liquid CO2 that has to be captured, transported and stored every year.
> why not just pull the electricity off the grid and convert methane/CO2/coal/oil straight into nanotubes for less cost and complexity?
The power plant also produces waste heat which presumably is useful for the reaction. So a combined plant that produces electricity and CNTs with zero carbon emissions is likely more efficient than using electricity to a) heat the whole thing b) pull CO2 out of the air c) run electrolysis.
The price for nanotubes will quickly drop:
> Using the new method, the researchers estimate that it would cost just $2,000/ton to produce
.. so at .75tons, it would still generate double the revenue from CNTs than from electricity. But still revenue is 1/3 energy and 2/3 CNT so it's still significantly a power plant.
>If we can incentivize people to make useful products out of all that CO2 just floating in the atmosphere, then maybe, just _maybe_, we can start fixing the mess we made.
I'm sure most people are picturing factories here, but using low/appropriate tech as well is essential. Building soil and woody biomass can absorb enormous amounts of carbon.
The question essentially becomes, how much biomass per hectare are we talking about? Absorbing the 350 teratonnes of human emitted carbon [1] over the 11.7 billion hectares of Earth's non-tundra land surface [2] works out to 30 tonnes of carbon per hectare. If you exclude deserts it's 42 tonnes per hectare, but the technology already exists to successfully "green" deserts.
That's 30 trees per hectare, at 1 tonne per tree.[3] Or 3 kg per square meter of soil carbon, the equivalent of 25 cm of topsoil Soil carbon is stored up to 40 meters down by deep rooted plants, so in practice this isn't a problem. [4]
Most of our land management is via agricultural, so agricultural reform is the only lever long enough to make a dent. Practically this means switching from soil destroying tillage to soil building cover crops, long-distance imported fertilizer to in-situ fertility produced by soil organisms[5], and ecologically unstable monocultures to resiliant polyculture and agroforestry systems.
If you run the numbers trying to use factories alone the cost is astronomical. It's larger* than the world's global energy infrastructure, because thermodynamics is working against you.
An overhaul of agriculture using modern environmental biology is the only thing with a lever long enough to make the numbers close. Plus it simultaneously solves the existential risks posed by our laughably unsustainable food production system and the collapse of ecosystem services by habitat destruction.[6]
> Absorbing the 350 teratonnes of human emitted carbon ...
And that was the first time I ever saw anyone throwing a number for how many tonnes we are really talking about in any debate I have seen either here or on AT.
Congrats! More numbers, less politics!
(Not saying it is correct, I haven't verified, -but unlike "celebrity X says we should do something now" this is something that can be measured and discussed rationally.)
The authors estimate that a "CC CNF" power plant would produce $835 of electricity and over $225,000 of nanotubes from a single metric ton of methane. At this point, economically, this is no longer a power plant: it is a carbon nanotube factory that has the side-effect of producing power. And if nanotubes are so valuable, the power generation part starts to look like a distraction: why not just pull the electricity off the grid and convert methane/CO2/coal/oil straight into nanotubes for less cost and complexity?
So really, this doesn't seem to be about power plants, so much as a (maybe) cheap way to make nanotubes from carbon. If we can incentivize people to make useful products out of all that CO2 just floating in the atmosphere, then maybe, just _maybe_, we can start fixing the mess we made.