If we had enormous amounts of spare energy, then we could generate "green" hydrogen (by electrolysis of water).
You could then run the Bosch reaction to combine that hydrogen with the carbon dioxide from DAC to get graphite and water. Graphite, being a solid, is much easier and safer to store than carbon dioxide - unlike gaseous carbon dioxide, it won't leak.
Alternatively, you could use the Sabatier reaction to combine hydrogen with carbon dioxide to make methane and water. Methane is natural gas, and has enormous applications, both as a fuel and as a chemical feedstock. Having a supply of zero-carbon (if burned) or negative carbon (as a feedstock) methane would make a lot of other processes zero-carbon or carbon-negative without having to change their processing.
In either case, the water produced can be fed back into the electrolysis. Theoretically, there would be no need for water in the Bosch process (the Sabatier only returns half the water you started with). In practice, the process is not fully circular, so you would need to top up for water that leaked or evaporated away. But if there is plenty of cheap energy, then you can use that for the reverse osmosis of seawater, so there is not reason for there to be a water shortage if there is plenty of cheap energy.
All of these processes are energy-intensive; they are perfect uses for excess energy produced by solar and wind. Indeed, by storing the hydrogen, you can use the hydrogen storage as energy storage to compensate for renewable intermittency, and then only use the surplus hydrogen produced beyond your storage capacity for the Bosch or Sabatier processes to convert DAC carbon dioxide into something storable or useful.
Thanks—like you, I think our planet’s future depends on science, but I didn’t know much about how it’s going. So this was very informative.
And I’ve concluded that we should make the carbon into diamonds for engagement rings and other jewelry. If there’s a surplus after that, we can bring back bedazzling. Everyone wins except the blood diamond industry.
Just read Termination Shock by Neal Stephenson, who tosses out the idea of Stratospheric Aerosol Injection (basically to mimic what volcanoes do) which is interesting but also seems like how every non-zombie post apocalyptic story starts out - humans playing whack-a-mole with ideas that just make shit downstream worse.
FYI, Dry Ice is more widely used in our society than we realize. As an example, when vaccine production started to ramp up, almost every dry-ice facility in the US was being requisitioned to manufacture the cold stuff to ship and store the vaccine. One of the side effects was disrupting part of the cheesemaking industry who also uses dry ice. (See https://www.wischeesemakersassn.org/news/essential-infrastructure-necessity-of-dry-ice-for-the-global-dairy-processing-industry).
Turns out Dry Ice is Infrastructure. Probably not a big enough piece of infrastructure to make DAC cost effective, but it's infrastructure nonetheless
If we had enormous amounts of spare energy, then we could generate "green" hydrogen (by electrolysis of water).
You could then run the Bosch reaction to combine that hydrogen with the carbon dioxide from DAC to get graphite and water. Graphite, being a solid, is much easier and safer to store than carbon dioxide - unlike gaseous carbon dioxide, it won't leak.
Alternatively, you could use the Sabatier reaction to combine hydrogen with carbon dioxide to make methane and water. Methane is natural gas, and has enormous applications, both as a fuel and as a chemical feedstock. Having a supply of zero-carbon (if burned) or negative carbon (as a feedstock) methane would make a lot of other processes zero-carbon or carbon-negative without having to change their processing.
In either case, the water produced can be fed back into the electrolysis. Theoretically, there would be no need for water in the Bosch process (the Sabatier only returns half the water you started with). In practice, the process is not fully circular, so you would need to top up for water that leaked or evaporated away. But if there is plenty of cheap energy, then you can use that for the reverse osmosis of seawater, so there is not reason for there to be a water shortage if there is plenty of cheap energy.
All of these processes are energy-intensive; they are perfect uses for excess energy produced by solar and wind. Indeed, by storing the hydrogen, you can use the hydrogen storage as energy storage to compensate for renewable intermittency, and then only use the surplus hydrogen produced beyond your storage capacity for the Bosch or Sabatier processes to convert DAC carbon dioxide into something storable or useful.
Thanks—like you, I think our planet’s future depends on science, but I didn’t know much about how it’s going. So this was very informative.
And I’ve concluded that we should make the carbon into diamonds for engagement rings and other jewelry. If there’s a surplus after that, we can bring back bedazzling. Everyone wins except the blood diamond industry.
Just read Termination Shock by Neal Stephenson, who tosses out the idea of Stratospheric Aerosol Injection (basically to mimic what volcanoes do) which is interesting but also seems like how every non-zombie post apocalyptic story starts out - humans playing whack-a-mole with ideas that just make shit downstream worse.
https://en.wikipedia.org/wiki/Stratospheric_aerosol_injection
Can't we turn carbon dioxide into some helium-like element that would cause it to disappear into space like those birthday balloons?