I believe Charm industrial is using the biochar process, but producing oil and pumping it into the ground. Even in fields, it’s a solid idea. And like you said

I believe Charm industrial is using the biochar process, but producing oil and pumping it into the ground. Even in fields, it’s a solid idea. And like you said, it’s recognized as being a very stable store of carbon for a very long time. The trick is getting feedstock nearby so you aren’t pumping tons of CO2 into the air to acquire, move and process it.