Originally Posted by
JDNSW
While it may have applications, elementary chemistry tells us that the endothermic process of breaking the carbon - oxygen bond to convert the carbon dioxide to carbon (not really coal) will take at least as much energy as was released by the exothermic reaction of making the bond by burning coal. This means that, assuming best practice power generation from burning the coal at 40% efficiency, to convert the carbon dioxide back to carbon will require 2.5 times the electricity that burning the coal produced. Assuming this new process is 100% efficient; which it won't be! Nothing ever is, in practice.
So I'm not sure what you would use it for.