:You seem to be a bit confused about the concept of "sustainable" energy.  Coal is a fossil fuel taking thousands of years to be produced.  It can not be replenished at the same rate as we use it.  That is the very definition of an unsustainable resource.  Just because the mining industry thinks that calling a new method of coal clean makes true does not mean that is actually the case.  This article is as balanced as you can get concerning such a flawed concept. It presents the ideas behind the concept while still presenting the very real and accurate criticisms of the concept.