Coal is a unique deposit. It is not being "renewed" by natural processes.

In the Carboniferous Era there were no organisms to break down wood, so it accumulated and became coal. Today we have fungi and bacteria that digest wood, causing it t decay and be recycled in the Carbon Cycle. The upshot is that there is no more coal production going on today. We have enough for abut 1,000 years in the ground, and we could burn it all if we chose. Provided we could handle all the CO2. 

So the Koch Brothers are onto something. Not sure what, but they are onto something.