3 ms·

One adult tree captures 25kg per year. One transatlantic flight releases 500kg per passenger. Twenty trees, per person, per flight. Get serious. IPCC projectio

by Mizza 4y ago

One adult tree captures 25kg per year. One transatlantic flight releases 500kg per passenger. Twenty trees, per person, per flight. Get serious. IPCC projections for a "good" scenario still depend on magical BECCS processes that don't yet exist., not flue scrubbing, which I think if anything will be away to keep coal plants online for _longer_. It's still valuable science, but don't get excited until there are major, major advancements in non-flue DAC/CCS.

PaulHoule 4y ago
There is nothing magical about BECCS. At the power plant it is a matter of putting together technology that already exists. All of the elements such as amine strippers, pyrolysis, oxy-fuel combustion, etc. have been around since the 1970s. The literature has a "stopped clock" appearance in that people have talked about these things in the context of "clean coal" and biofuels for a long time without anything being built. There are two problems with it. One of them is that any kind of carbon capture is expensive and competes directly with a power plant (maybe the same power plant) without the CCS equipment. To win that competition, the operator of the power plant either needs to be fined for emitting CO₂ or has to be paid for capturing it, to the tune of $50-$100 per tonne. Another is that the ecological accounting for biofuels is frequently not favorable. When you consider water consumption, effects of land use, and the effects of inputs, many biofuel schemes (such as Ethanol from corn in the US) seem to be a net negative. The cheapest BECCS scheme is to capture CO₂ from the alcohol fermentation process, this has been implemented with great success https://bioenergyinternational.com/adm-starts-commercial-scale-ccs-decatur-ethanol-plant/ https://bioenergyinternational.com/adm-starts-commercial-sca... Ethanol from sugarcane in Brazil is much better from an ecological and economic perspective and it would cost something like $30 a tonne to capture CO₂ and inject it into a saline aquifer but politically it seems impossible given that most international bodies think that the real problem in Brazil is deforestation and that somehow promoting agriculture in Brazil is going to cause deforestation despite the fact that the Ethanol industry is mostly around São Paulo and nowhere near the rainforest. In principle there might be some agreement that Brazil gets credits for BECCS and also gets credits for protecting the rainforest but the latter is somewhat nonsensical in that there is a mismatch in time between processes that emit CO₂ (say you spend 5 hours on a plane) and the need to protect a forest forever to sequester a finite amount of CO₂.
- Mizza 4y ago
  Why is sugarcane in Brazil any better than corn in the US? If they use petrochemical fertilizer, the problem is the same. You cannot sequester a ton of CO2 for $30/tn anywhere in the world right now. You can't even do it for five times that. If what you say were true, I'd be able to clean up after my own existence right now, which I can't do. I can only buy scammy "credits" and "offsets".
  - PaulHoule 4y ago
    See https://biowesleyan.wordpress.com/first-generation-biofuels/ethanol/case-study-brazil/sugarcane-vs-corn-based-ethanol/ https://biowesleyan.wordpress.com/first-generation-biofuels/... The advantage of corn over other crops is that it flourishes in the presence of nitrogen fertilizer. Sugarcane is not so hungry. The cost of capturing fermentation CO₂ is low because fermentation CO₂ is almost pure with very little nitrogen in it. Thus almost all of the cost is the cost of compressing the CO₂, pumping it, and injecting it underground which is about $30 a tonne. Even a few percent of nitrogen will cause the CO₂ to misbehave while pumping, so capturing CO₂ from a combustion stream requires some kind of separation which historically has been an aniline stripper or something like the rectisol process, but maybe it will be aluminum formate or something else in the future. The aniline stripper costs about $50 a tonne. The trouble with capturing fermentation CO₂ is that it is not scalable. There is a certain amount of it produced and it isn't enough to "save the Earth" but it is a low hanging fruit and it would help in the process in validating sequestration, as there are all kinds of questions about the permanence and safety of saline aquifer injection. (Don't get me started about the CarbFix water sequestration project...) As for why you can't buy any good carbon credits it is the proliferation of junk carbon credits at low prices that keeps good ones off the market. Another problem is that many schemes are using the CO₂ to produce more oil https://www.reuters.com/article/us-usa-energy-carbon-capture/problems-plagued-u-s-co2-capture-project-before-shutdown-document-idUSKCN2523K8 https://www.reuters.com/article/us-usa-energy-carbon-capture... which on one hand is a real market for the CO₂ (in Texas you can drill and get CO₂ in some places and since the 1980s they will pump it sideways and use it for enhanced oil recovery) but doing so seems to be more problem than solution and it ties the project economically to the up-and-down cycles of the oil industry.
flavius29663 4y ago
You're failing to put things in perspective. There are 500 trees on earth for each human being. That would mean they can absorb 12500 kg per year. Also, tree are NOT the largest natural CO2 sink, oceans absorb more. Overall, the biosphere absorbs about 50% of total human emissions (25% by land plants and 25% by oceans). I think that once we drop the CO2 emissions enough, the nature will quickly scrub it out of the air, we don't need to get negative ourselves, just drop close to zero and nature should balance itself pretty quick.
- Mizza 4y ago
  It's a carbon _cycle_. We've spent a hundreds of years adding new carbon to that cycle as fast as our technology will allow, which is now very fast. It will remain in the cycle unless we sequester it back into the ground. Plants (for the most part) aren't CO2 limited, they're nitrogen limited. The climate also isn't something that will just snap happily back into place. We're in a local minima. If we climb up this hill, we won't like what we find in the next valley.
- klyrs 4y ago
  Oceans absorbing CO2 results in acidification which is already harming the oceanic life cycle. We really want to tilt the balance away from the oceans, because the consequences of a dead ocean are dire.

by Mizza 4y ago

PaulHoule 4y ago

There is nothing magical about BECCS. At the power plant it is a matter of putting together technology that already exists. All of the elements such as amine strippers, pyrolysis, oxy-fuel combustion, etc. have been around since the 1970s. The literature has a "stopped clock" appearance in that people have talked about these things in the context of "clean coal" and biofuels for a long time without anything being built. There are two problems with it. One of them is that any kind of carbon capture is expensive and competes directly with a power plant (maybe the same power plant) without the CCS equipment. To win that competition, the operator of the power plant either needs to be fined for emitting CO₂ or has to be paid for capturing it, to the tune of $50-$100 per tonne. Another is that the ecological accounting for biofuels is frequently not favorable. When you consider water consumption, effects of land use, and the effects of inputs, many biofuel schemes (such as Ethanol from corn in the US) seem to be a net negative. The cheapest BECCS scheme is to capture CO₂ from the alcohol fermentation process, this has been implemented with great success https://bioenergyinternational.com/adm-starts-commercial-scale-ccs-decatur-ethanol-plant/ https://bioenergyinternational.com/adm-starts-commercial-sca... Ethanol from sugarcane in Brazil is much better from an ecological and economic perspective and it would cost something like $30 a tonne to capture CO₂ and inject it into a saline aquifer but politically it seems impossible given that most international bodies think that the real problem in Brazil is deforestation and that somehow promoting agriculture in Brazil is going to cause deforestation despite the fact that the Ethanol industry is mostly around São Paulo and nowhere near the rainforest. In principle there might be some agreement that Brazil gets credits for BECCS and also gets credits for protecting the rainforest but the latter is somewhat nonsensical in that there is a mismatch in time between processes that emit CO₂ (say you spend 5 hours on a plane) and the need to protect a forest forever to sequester a finite amount of CO₂.

Mizza 4y ago
Why is sugarcane in Brazil any better than corn in the US? If they use petrochemical fertilizer, the problem is the same. You cannot sequester a ton of CO2 for $30/tn anywhere in the world right now. You can't even do it for five times that. If what you say were true, I'd be able to clean up after my own existence right now, which I can't do. I can only buy scammy "credits" and "offsets".
- PaulHoule 4y ago
  See https://biowesleyan.wordpress.com/first-generation-biofuels/ethanol/case-study-brazil/sugarcane-vs-corn-based-ethanol/ https://biowesleyan.wordpress.com/first-generation-biofuels/... The advantage of corn over other crops is that it flourishes in the presence of nitrogen fertilizer. Sugarcane is not so hungry. The cost of capturing fermentation CO₂ is low because fermentation CO₂ is almost pure with very little nitrogen in it. Thus almost all of the cost is the cost of compressing the CO₂, pumping it, and injecting it underground which is about $30 a tonne. Even a few percent of nitrogen will cause the CO₂ to misbehave while pumping, so capturing CO₂ from a combustion stream requires some kind of separation which historically has been an aniline stripper or something like the rectisol process, but maybe it will be aluminum formate or something else in the future. The aniline stripper costs about $50 a tonne. The trouble with capturing fermentation CO₂ is that it is not scalable. There is a certain amount of it produced and it isn't enough to "save the Earth" but it is a low hanging fruit and it would help in the process in validating sequestration, as there are all kinds of questions about the permanence and safety of saline aquifer injection. (Don't get me started about the CarbFix water sequestration project...) As for why you can't buy any good carbon credits it is the proliferation of junk carbon credits at low prices that keeps good ones off the market. Another problem is that many schemes are using the CO₂ to produce more oil https://www.reuters.com/article/us-usa-energy-carbon-capture/problems-plagued-u-s-co2-capture-project-before-shutdown-document-idUSKCN2523K8 https://www.reuters.com/article/us-usa-energy-carbon-capture... which on one hand is a real market for the CO₂ (in Texas you can drill and get CO₂ in some places and since the 1980s they will pump it sideways and use it for enhanced oil recovery) but doing so seems to be more problem than solution and it ties the project economically to the up-and-down cycles of the oil industry.

flavius29663 4y ago

You're failing to put things in perspective. There are 500 trees on earth for each human being. That would mean they can absorb 12500 kg per year. Also, tree are NOT the largest natural CO2 sink, oceans absorb more. Overall, the biosphere absorbs about 50% of total human emissions (25% by land plants and 25% by oceans). I think that once we drop the CO2 emissions enough, the nature will quickly scrub it out of the air, we don't need to get negative ourselves, just drop close to zero and nature should balance itself pretty quick.

Mizza 4y ago
It's a carbon _cycle_. We've spent a hundreds of years adding new carbon to that cycle as fast as our technology will allow, which is now very fast. It will remain in the cycle unless we sequester it back into the ground. Plants (for the most part) aren't CO2 limited, they're nitrogen limited. The climate also isn't something that will just snap happily back into place. We're in a local minima. If we climb up this hill, we won't like what we find in the next valley.
klyrs 4y ago
Oceans absorbing CO2 results in acidification which is already harming the oceanic life cycle. We really want to tilt the balance away from the oceans, because the consequences of a dead ocean are dire.