Here is a good background article on coal as a dirty fuel and its longevity at present rate of consumption and additions to reserves through discoveries.
Peak Coal, 14 April 2014 http://tceconomist.blogspot.gr/2014/04/peak-coal.html
The Cultural Economist
In terms of Peak Coal, we actually will have two peaks: one measured by heat content, and one measured by maximum tons produced. Considering the decline of our anthracite resources, and the increasing production of sub-bituminous and lignite coals, there are those who believe we have already passed Peak Coal based on heat (energy) content...
[S]ome Western nations may temporarily reduce their consumption of coal, international demand will increase – most notably in the Western Pacific region...
China now consumes more coal (50.6 percent of world consumption) than all other nations put together. That means, of course, China also pollutes the air with more combustion products from the consumption of coal than any other nation. Large coal fired plants are under construction or in proposal stages for many nations including China, India, Germany, Russia, Vietnam, Pakistan, Sri Lanka and on and on.