[Dylan16807]

One of the options is just injecting CO2 into very deep caves/water. And it will then react with many rocks all by itself!

The company that Microsoft is buying capture from is using lots of energy to remove CO2 from rocks, but that's because they're working to pull more CO2 from normal air. When you have an exhaust pipe it's already concentrated and you can separate it out much more easily.

[alexey-salmin]

Injection of CO2 into water happens naturally in the ocean. Unfortunately ocean didn't respond to any of the VC calls.

Injecting CO2 into rocks "all by itself" is extremely slow because it's exothermic and because surface of rocks is too small. You need to crush the rocks (energy) and heat them up (energy).

[Dylan16807]

> happens naturally in the ocean

That's not fast enough and also risks making the ocean too acidic.

> Injecting CO2 into rocks "all by itself" is extremely slow

By injection I meant injection. Drilling a deep hole and pushing the CO2 out the other end.

Only the reaction happens by itself.

With the right structure underground the CO2 can spread over an enormous surface area at a high concentration that promotes reactions. But even if it that takes too long, each well doesn't need to operate forever.