I really enjoyed this article and the common sense presentation of concepts. It is always best to revert to 101 concepts, they will always serve.
I am an industrial chemist, and sometimes one gets a "non-scientific feel" or "intuition" about a process in terms of energy flow and entropy (Gibb's Free Energy).
In terms of so-called "renewables", there is no such thing as renewable as spelled out by the Law's of Physics and Thermodynamics. Having said that, I have yet to see a "green energy" solution that adds up or makes any sense, except for nuclear and fossil. The energy density due to E=mc^2 can't be beat, and fossil is close behind because of it's energy density and transportability. I wish it was different, but magical thinking won't help. A build out of stable baseline nuclear is a critical imperative. Wind and solar have no chance due to low "energy density" and intermittantcy.
CO2 capture is a disaster energy wise in particular, it won't make any real dent in the CO2 levels. Le Chatelier's principle tells us so. The ocean's cover 70 % of the earth and are the largest CO2 sink. CO2 will just come back out of the oceans if there is a lack of CO2 and equilibrium will be reached again and again. The sun and albedo have orders of magnitude greater effect on warming than CO2 anyway. These are all Chem 101 and Physics 101 principles.
“A typical coal power plant emits a tonne of CO₂ for every 1,000 kWh of electricity it generates. Meanwhile, we learned that the energy needed to recapture 1 tonne of CO₂ from the air is at least 1,400 kWh. This means that recapturing the emissions of a coal power plant takes more energy than the coal plant produces!”
As you state in the following section, the emissions from the power plant flue gas has concentrated CO2. So, how can you say that recapturing the emissions of a coal plant takes more energy than it produces?
You are comparing the energy to capture CO2 from air with the energy produced by a power plant. What is the energy needed to capture CO2 from flue gas? Instead of the 1400kWh to capture CO2 from air, your number should be closer to 300kWh to capture CO2 from flue gas, leaving a 700net kWh energy from a coal plant.
Thanks for writing this. Having a physics background this was always my skeptical take on carbon capture. I mean you can always do it, just realize it will take more energy (greater cost) than avoiding the release. Still, if you hypothesize an clean-energy abundant future, it may very well be worth considering. At the moment it does not make sense; if you can put a dollar towards clean energy put it there and not direct air capture.
Capturing concentrated CO2 from flue gas is a lot more efficient than capturing from air. This article compares the energy required for CO2 capture from air with the energy produced from a power plant. It's not comparing apples to apples.
This article needs to be understood in the context of the most recent IPCC (6th) assessment, which argues that, essentially for all scenarios they've looked at, it will be necessary to have a period of 'negative' CO2 emissions - which refers not to CO2 extraction from flue gases but rather from the atmosphere, i.e., direct air capture of CO2 (DAC). And this article points out that extracting CO2 from the atmosphere is indeed going to be very expensive, even at the optimistic cost of $100/ton of CO2 removed. You are of course right about the far lower costs of extracting CO2 at the point of emission (which this article also points out) - but the sad state of affairs is that this does not address the problem pointed out by the IPCC ...
There is so much misunderstanding in this discussion. Yes, we MAY face a situation where it's necessary to capture and sequester CO2 that's already been emitted, but it makes no sense to devote resources to that until we've ramped down nearly ALL of fossil fuel emissions. It makes no sense to devote any renewable energy to DAC operations when that energy could instead be used to displace fossil energy that's still being generated. And when the time comes to spend money on negative emissions, it makes far more sense to do it via biomass energy with CO2 capture (BECCS), which we already know how to do. It will take robust oversight, of course, to prevent ecosystem damage, but at least it doesn't require magic.
I really enjoyed this article and the common sense presentation of concepts. It is always best to revert to 101 concepts, they will always serve.
I am an industrial chemist, and sometimes one gets a "non-scientific feel" or "intuition" about a process in terms of energy flow and entropy (Gibb's Free Energy).
In terms of so-called "renewables", there is no such thing as renewable as spelled out by the Law's of Physics and Thermodynamics. Having said that, I have yet to see a "green energy" solution that adds up or makes any sense, except for nuclear and fossil. The energy density due to E=mc^2 can't be beat, and fossil is close behind because of it's energy density and transportability. I wish it was different, but magical thinking won't help. A build out of stable baseline nuclear is a critical imperative. Wind and solar have no chance due to low "energy density" and intermittantcy.
CO2 capture is a disaster energy wise in particular, it won't make any real dent in the CO2 levels. Le Chatelier's principle tells us so. The ocean's cover 70 % of the earth and are the largest CO2 sink. CO2 will just come back out of the oceans if there is a lack of CO2 and equilibrium will be reached again and again. The sun and albedo have orders of magnitude greater effect on warming than CO2 anyway. These are all Chem 101 and Physics 101 principles.
Energy doesn't for capture doesn't have to come from the electric grid. How about the sun and photosynthesis or geological processes.
I’m particularly confused by this statement:
“A typical coal power plant emits a tonne of CO₂ for every 1,000 kWh of electricity it generates. Meanwhile, we learned that the energy needed to recapture 1 tonne of CO₂ from the air is at least 1,400 kWh. This means that recapturing the emissions of a coal power plant takes more energy than the coal plant produces!”
As you state in the following section, the emissions from the power plant flue gas has concentrated CO2. So, how can you say that recapturing the emissions of a coal plant takes more energy than it produces?
You are comparing the energy to capture CO2 from air with the energy produced by a power plant. What is the energy needed to capture CO2 from flue gas? Instead of the 1400kWh to capture CO2 from air, your number should be closer to 300kWh to capture CO2 from flue gas, leaving a 700net kWh energy from a coal plant.
Thanks for writing this. Having a physics background this was always my skeptical take on carbon capture. I mean you can always do it, just realize it will take more energy (greater cost) than avoiding the release. Still, if you hypothesize an clean-energy abundant future, it may very well be worth considering. At the moment it does not make sense; if you can put a dollar towards clean energy put it there and not direct air capture.
Capturing concentrated CO2 from flue gas is a lot more efficient than capturing from air. This article compares the energy required for CO2 capture from air with the energy produced from a power plant. It's not comparing apples to apples.
This article needs to be understood in the context of the most recent IPCC (6th) assessment, which argues that, essentially for all scenarios they've looked at, it will be necessary to have a period of 'negative' CO2 emissions - which refers not to CO2 extraction from flue gases but rather from the atmosphere, i.e., direct air capture of CO2 (DAC). And this article points out that extracting CO2 from the atmosphere is indeed going to be very expensive, even at the optimistic cost of $100/ton of CO2 removed. You are of course right about the far lower costs of extracting CO2 at the point of emission (which this article also points out) - but the sad state of affairs is that this does not address the problem pointed out by the IPCC ...
There is so much misunderstanding in this discussion. Yes, we MAY face a situation where it's necessary to capture and sequester CO2 that's already been emitted, but it makes no sense to devote resources to that until we've ramped down nearly ALL of fossil fuel emissions. It makes no sense to devote any renewable energy to DAC operations when that energy could instead be used to displace fossil energy that's still being generated. And when the time comes to spend money on negative emissions, it makes far more sense to do it via biomass energy with CO2 capture (BECCS), which we already know how to do. It will take robust oversight, of course, to prevent ecosystem damage, but at least it doesn't require magic.