icyliquid

The byproduct is in liquid or gas form. The source was in solid form and unable to affect the atmosphere. Putting liquid or gas back into the ground is risky (leaks, tectonics, etc). It has also been shown to leach into the soil and pollute it in some cases.

EDIT: as /u/MrBlaaaaah mentioned, usually these areas are geologically stable, but leaks can happen.

Don't worry, its not creepy

don't wet yourself or your clothes

I really hope piss doesn't count

If you hired a cleaner for your house and when you came home everything looked nice, but later you found that instead of vacuuming they had just swept all the dirt under your couches and rugs, would you feel like your house was "clean"?

If, when confronted about this process, the cleaner said that they had "sequestered" the dirt, would you be pleased with that answer?

EDIT: Since its apparently not clear, I'm simply objecting to the concept of coal being called "clean". It is dirty, there's no way around that. If you want to mitigate the contamination of the environment with CCS, then fine, but that's not somehow making coal "clean". You've just moved the damage elsewhere, either in space or in time.

Thanks, I definitely did that before posting. My comment stands.

CCS does delay the release of CO2 emissions for some number of years, from hundreds to potentially thousands. That's nice for those of us around right now.

CCS does not somehow eliminate the damaging effects of that CO2 altogether. CCS does not make burning coal "clean". There is still a destructive byproduct, it is simply moved to a temporary (in terms of geological timescales) storage area until some future generation either deals with it, or not.

If CO2 emissions were sequestered by George Washington, it could very well be something the current generation has to deal with. Since we're starting now, it will be something that humanity has to deal with in the relatively near future, but this time they won't have the easy options available to them.