There is no doubt that saline injection on a large scale will hold CO2 for a short time. The 10,000 year time span that we'd like to hold it for is a long time.
A bit pessimistically, the actual injection into a saline aquifer costs something around $20 a ton, but capturing CO2 from a power plant with an amine stripper is around $80 a ton. Direct air capture is a lot more than that.
We aren't seeing many carbon capture projects, even the low hanging fruit like
which is profitable at $20 a ton is not being developed because "junk carbon credits" are available at lower prices.
(I know the corn-based Ethanol at the Decatur facility is environmentally negative in a lot of ways... But put that kind of system on a sugarcane Ethanol plant in Brazil, near Sao Paulo and nowhere near the rainforest, and it would be a different story.)
A bit pessimistically, the actual injection into a saline aquifer costs something around $20 a ton, but capturing CO2 from a power plant with an amine stripper is around $80 a ton. Direct air capture is a lot more than that.
We aren't seeing many carbon capture projects, even the low hanging fruit like
https://www.energy.gov/sites/prod/files/2017/10/f38/mcdonald...
which is profitable at $20 a ton is not being developed because "junk carbon credits" are available at lower prices.
(I know the corn-based Ethanol at the Decatur facility is environmentally negative in a lot of ways... But put that kind of system on a sugarcane Ethanol plant in Brazil, near Sao Paulo and nowhere near the rainforest, and it would be a different story.)