I wrote the comment below in response to another article, but it is applicable here. I should note that the technology to convert CO2 to say hydrocarbons is well known (and my current work is on making it economically interesting), my issue is with trying to extract CO2 from the atmosphere, which is very inefficient.
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This is actually a very bad idea and a complete waste of money which should have been used for other projects. It reminds me of another bad idea, which just will not die - extracting water from air by cooling it.
Right now, we have several technologies ready to go. Starting with the most cost-effective, and omitting the "use less" scenarios:
1. Replacement of fossil fuel power plants with carbon free electricity such as wind and solar power (also geothermal, where possible and nuclear, where palatable). Cost per tonne of CO2 saved: less than zero for about 30% of current generation, and "very low" for a good portion of the remainder.
2. Sequestration of concentrated CO2 streams, such as those produced in natural gas processing. Cost: $20-$40 per tonne.
3. Biosequestration, ie tree planting. Cost varies greatly, maybe $15-$50 per tonne.
The approaches above are the only ones that are actually used in the industry today, but there is plenty of room to do more. The approaches below are considered to be economically prohibitive, and AFAIK are not in use:
4. Post-combustion carbon capture: Scrubbing the CO2 from exhaust gases of power plants etc, where the CO2 concentration is 10-20%. Cost: $50-100/tonne, PLUS the cost of sequestration, as above.
5. Pre-combustion carbon capture: here, the carbon is removed from the fuel and sequestered, and only the hydrogen is burned. Cost: $80-150/tonne, but sequestration cost is low.
and then we have:
6. Removal of CO2 from the atmosphere. The article says the cost may be "under $100/tonne", but the serious estimates I have seen are circa $500/tonne. Consider that the CO2 concentration in air is around 0.04%, cf post combustion concentrations of 10-20%. Regardless of the advances in technology, this will never be as cheap as post-combustion carbon capture, which is essentially the same process but with 250 times less throughput.
You are missing the point; this is a fuel production system that effectively removes the need to capture carbon: i.e. the notion of turning air into something you put in the ground too offset the carbon we are removing from it to burn. I agree that is not a valid economical proposition other than making people feel slightly less guilty about burning fossil fuels. It's actually a rather dumb idea since you are taking something that is expensive and wasteful and spend yet more to offset somewhat just how wasteful it is.
Producing fuel from the captured carbon, sidesteps the whole problem of needing fossil fuels at all. So, you are not offsetting anything; you are simply producing the fuel that you need in a way that is clean.
You seem to be arguing that it can't be done because 'numbers'. 1) those numbers lack citations 2) they are not set in stone. The question you should be asking yourself is how badly wrong your numbers are and what it would take to make the numbers right.
Turns out that this whole game of producing fuels from thin air is mostly a function of clean energy cost per kwh. Simply put, this is not constant. It varies wildly geographically. And it's also not constant over time. It's been dropping for decades at a rather impressive pace and projected to continue to do so. So, the only question is when will it become completely uneconomical to mine fossil fuels as opposed to simply converting co2 into whatever carbohydrates we need.
I'm guessing the persons behind Prometheus might be a bit optimistic here (i.e. suggesting it could be economical right now) but I wouldn't see that as a fundamental issue. If the answer is that those cost lines cross anywhere in the next decades, this would be still be an extremely lucrative investment. The mere possibility that this could be economical right now or in the very near term, makes this quite exciting.
>You are missing the point; this is a fuel production system that effectively removes the need to capture carbon
No... the first step in the proposed process is to capture the CO2 from the air, what I describe in point 6 of my comment.
>You seem to be arguing that it can't be done because 'numbers'
No... It can be done. But it should not be done. Because 'numbers' tell you there are other things that should be done instead. Right now.
>those numbers lack citations... you should be asking yourself is how badly wrong your numbers are...
I work in this field. I have literally hundreds of possible citations. Pick a number you most disagree with, and I will provide you a citation. Alternatively, provide me a counter-citation and I will review and comment on it for you.
> The mere possibility that this could be economical right now or in the very near term...
Here is what I am trying to tell you: this cannot be economical until all the other, much more economical options which I have listed are pretty much fully used up. Considering that we have barely made a dent in the first of these, this will certainly not be economical in the near term, or in the medium term (and in my opinion, never, because biosequestration is so much cheaper).
Eh no. You are talking about carbon capture as a way to offset fossil fuel consumption. I'm talking about reducing fossil fuel consumption by instead producing non fossil fuels. Apples and oranges. The point of that is not to capture the carbon but to utilize it as fuel. With this technology, that is neither impossible nor prohibitively expensive/unecomincal. Unlike the six schemes you outline that are about not producing any fuel whatsoever so we can continue to produce it the old way while hopefully removing some of the CO2 that we are thus putting there (hence the need to capture it).
You're using numbers to categorically dismiss what seems to be a pretty well reasoned case for doing this as "impossible" because 'numbers' for various carbon capturing schemes.
If you are capturing carbon, you might as well do it in a form where you can actually utilize it for fuel. That's a pretty nice proposition. Prometheus seems to be one of several startups with some plans for making this happen.
You're saying they are wasting time. I'm saying that layering the cost that you outline on top of the existing fossil fuel production cost only makes their value proposition even more attractive than it already is without doing that. Bottom line is anything that reduces the amount of oil we pump up and burn is a good thing. Carbon capture schemes seem more like an excuse to drag our heels doing that than something that is actually likely to produce results on a timescale that isn't measured in centuries.
>The point of that is not to capture the carbon but to utilize it as fuel.
>If you are capturing carbon, you might as well do it in a form where you can actually utilize it for fuel.
Do you understand that the Prometheus proposes to first capture the carbon and then convert it to fuel?
I have no objection to the "convert it to fuel" part. Just to the capture from atmosphere, which is the most inefficient way.
I understand you perfectly. I just don't agree with a single sentence of it. The semantics of carbon capture for you seem to mean to capture some (tiny) percentage of the absolutely epic levels of fossil carbon we put into it today.
The point of Prometeus is to take no fossil carbon whatsoever (0%) and create the fuel directly from the CO2 already in the air and indeed put it back there when it is burned. It's not capturing so much as reusing what is already there. It's by definition the most efficient way. It's 100% efficient.
None of the things you listed actually produce fuel. So they are 0% efficient. At best they offset some meaningless percentage of fossil fuels. Actually raising the cost of those fossil fuels to pay for more meaningful percentages (like more than 1 digit?), just strengthens the business case for Prometheus. The more costly fossil fuel gets, the more attractive Prometheus gets. As it is, they seem to be claiming to be cost effective as is.
>I just don't agree with a single sentence of it.... The more costly fossil fuel gets, the more attractive Prometheus gets. As it is, they seem to be claiming to be cost effective as is.
Okay. Invest in Prometheus. I think the net result will be an increase in CO2 emissions, because all the activity will fail to deliver any viable atmospheric CO2 capture plants, ever. Let's check on this say 20 years from now. If I'm right, buy me a beer.
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This is actually a very bad idea and a complete waste of money which should have been used for other projects. It reminds me of another bad idea, which just will not die - extracting water from air by cooling it. Right now, we have several technologies ready to go. Starting with the most cost-effective, and omitting the "use less" scenarios:
1. Replacement of fossil fuel power plants with carbon free electricity such as wind and solar power (also geothermal, where possible and nuclear, where palatable). Cost per tonne of CO2 saved: less than zero for about 30% of current generation, and "very low" for a good portion of the remainder.
2. Sequestration of concentrated CO2 streams, such as those produced in natural gas processing. Cost: $20-$40 per tonne.
3. Biosequestration, ie tree planting. Cost varies greatly, maybe $15-$50 per tonne.
The approaches above are the only ones that are actually used in the industry today, but there is plenty of room to do more. The approaches below are considered to be economically prohibitive, and AFAIK are not in use:
4. Post-combustion carbon capture: Scrubbing the CO2 from exhaust gases of power plants etc, where the CO2 concentration is 10-20%. Cost: $50-100/tonne, PLUS the cost of sequestration, as above.
5. Pre-combustion carbon capture: here, the carbon is removed from the fuel and sequestered, and only the hydrogen is burned. Cost: $80-150/tonne, but sequestration cost is low.
and then we have:
6. Removal of CO2 from the atmosphere. The article says the cost may be "under $100/tonne", but the serious estimates I have seen are circa $500/tonne. Consider that the CO2 concentration in air is around 0.04%, cf post combustion concentrations of 10-20%. Regardless of the advances in technology, this will never be as cheap as post-combustion carbon capture, which is essentially the same process but with 250 times less throughput.