Uploaded May 2025 | Updated September 2026, 2 weeks ago
I met up with Chemical Engineer Paul Martin when he was in Sydney recently and asked him for his thoughts about direct air capture DAC. This is what he has to say:
Direct air capture is a way to use electricity that we need to electrify to decarbonise via electrification in a very inefficient way, to pull small amounts of CO₂ out of the atmosphere. And it's intellectually appealing because it's simple-minded, circular economy thinking. "Let's have a circular economy and CO₂. Let's capture CO₂ from the atmosphere, react it with hydrogen to make fuels, which will then burn, which will generate CO₂, put it back in the atmosphere, and we can just pull it back out again."
Why don't we just connect here and there with a wire and get rid of the carbon middleman? Wherever that energy is actually coming from to run the DAC, could we just use that to get rid of the power plant? And wouldn't that make more sense?
The other thing is, we need some carbon-negative technologies because there are some emissions that are going to be very difficult to get rid of. Cement making is one, and another is the disposal of hazardous materials that we make as chemicals, for instance, that are best disposed of by incineration because it's very difficult to detoxify them otherwise.
Those things will require either carbon capture at source—which energetically makes way more sense than pulling CO₂ out of the atmosphere—or, if we can't do it at source, then pulling CO₂ from the atmosphere and burying it. And we'll need to be able to capture carbon and remove it from the atmosphere in some way or another.
But what it seems to me that we're missing is that there's already the biosphere. We're doing a lot of this, and we could intervene in the biosphere to let nature do the hard part, which is the solar capture of CO₂ by means of biomass, and then help it along by, for instance, pyrolyzing biomass to produce biochar, which we then return to the soils or the forest from whence it came.
And by so doing, basically replace the role that fire used to have in the ecosystem, with us getting the energy rather than the energy just being dissipated as it would be in a wildfire.
So I think there are clever ways that we could go about doing the same thing—accomplishing the same thing—which is taking CO₂ and not returning it to the biosphere in a way that just becomes CO₂ again.
So I think that makes more sense than building big vacuum cleaners.
If you would like to help develop the Engineering with Rosie channel, you could consider joining the Patreon community, where there is a chat community (and Patreon-only Discord server) about topics covered in the videos and suggestions for future videos and production quality improvements. patreon.com/engineeringwithrosie
Or for a one-off contribution you can support by buying a coffee ☕️ here —
buymeacoffee.com/engwithrosie
The Engineering with Rosie team is:
Rosemary Barnes: presenter, producer, writer
Javi Diez: editor linkedin.com/in/javierdiezsuarez/?locale=en_US
I met up with Chemical Engineer Paul Martin when he was in Sydney recently and asked him for his thoughts about direct air capture DAC. This is what he has to say:
Direct air capture is a way to use electricity that we need to electrify to decarbonise via electrification in a very inefficient way, to pull small amounts of CO₂ out of the atmosphere. And it's intellectually appealing because it's simple-minded, circular economy thinking. "Let's have a circular economy and CO₂. Let's capture CO₂ from the atmosphere, react it with hydrogen to make fuels, which will then burn, which will generate CO₂, put it back in the atmosphere, and we can just pull it back out again."
Why don't we just connect here and there with a wire and get rid of the carbon middleman? Wherever that energy is actually coming from to run the DAC, could we just use that to get rid of the power plant? And wouldn't that make more sense?
The other thing is, we need some carbon-negative technologies because there are some emissions that are going to be very difficult to get rid of. Cement making is one, and another is the disposal of hazardous materials that we make as chemicals, for instance, that are best disposed of by incineration because it's very difficult to detoxify them otherwise.
Those things will require either carbon capture at source—which energetically makes way more sense than pulling CO₂ out of the atmosphere—or, if we can't do it at source, then pulling CO₂ from the atmosphere and burying it. And we'll need to be able to capture carbon and remove it from the atmosphere in some way or another.
But what it seems to me that we're missing is that there's already the biosphere. We're doing a lot of this, and we could intervene in the biosphere to let nature do the hard part, which is the solar capture of CO₂ by means of biomass, and then help it along by, for instance, pyrolyzing biomass to produce biochar, which we then return to the soils or the forest from whence it came.
And by so doing, basically replace the role that fire used to have in the ecosystem, with us getting the energy rather than the energy just being dissipated as it would be in a wildfire.
So I think there are clever ways that we could go about doing the same thing—accomplishing the same thing—which is taking CO₂ and not returning it to the biosphere in a way that just becomes CO₂ again.
So I think that makes more sense than building big vacuum cleaners.
If you would like to help develop the Engineering with Rosie channel, you could consider joining the Patreon community, where there is a chat community (and Patreon-only Discord server) about topics covered in the videos and suggestions for future videos and production quality improvements. patreon.com/engineeringwithrosie
Or for a one-off contribution you can support by buying a coffee ☕️ here —
buymeacoffee.com/engwithrosie
The Engineering with Rosie team is:
Rosemary Barnes: presenter, producer, writer
Javi Diez: editor linkedin.com/in/javierdiezsuarez/?locale=en_US
