Carbon dioxide a tiny fraction of the atmosphere, even in concentrations which are immediately harmful to human life.
At the moment it's 400 parts per million. So in order to extract 1kg of Carbon Dioxide from the atmosphere you have to pump 2500kg of air through the system. This alone makes it unlikely we can do this profitability.
You then need to extract the carbon dioxide using some technique which will probably involve cooling or pressuring that volume of air. Before finally transforming carbon dioxide, a very stable chemical compound, into a reagent which is actually useful (probably carbon monoxide).
Terraform Industries (and others, like Synhelion) has a plausible if slightly optimistic target to be price competitive with fossil fuels for methane in the early 2030s.
Some places with very cheap to extract hydrocarbons like Saudi Arabia may be able to compete for a very long time, but there are many futures where most of humanity's hydrocarbon consumption (including the ones used for the chemical industry, plastics, etc) derives from atmospheric carbon.
And this can happen fast, the world (mostly China) has developed a truly massive manufacturing capacity for PV.
If such a technology was possible then it would be far better to start with carbon capture from existing emitters. The concentration of CO2 being easily 3 orders of magnitude higher.
Higher CO2 concentration is better but certainly not needed, it doesn't make or break the economics.
I don't see a future where technologies which are massively inefficient reach their break even cost before other energy intensive activities or more efficient grid scale storage soak up the excess.
And yes “energy” in general won’t be free. We still need to build the generation and distribution systems. But we reached a point where just dumping solar on all _new_ roofs rounds to essentially free (the costs are the labor and the access to qualified personnel). The exact same is currently happening to batteries. Any transformer project will be able to just integrate 4-12 hours of batteries without getting meaningfully more expensive. The same for every domestic or industry service upgrade
We are not there yet. But give it another 5 years and we will. And then we are only talking about financing what little distribution system we will need (basically you only need average-sized cables not peak-sized ones) and a capacity market for backup power systems (also only for average residual demand). And those we simply cannot (efficiently) finance by a per-kWh-used charge
Will it be that cheap? I think so, given that trees and grass etc. exist and get their carbon from the air.
Thats what makes this even less attractive-- those plants are expensive to build and operate and you can't even really use the product in the most obvious ways.
> If electricity is sufficiently cheap