It may be a bit premature to write off coal yet, The International Energy Authority stated in 2018 that coal usage world wide would increase by 30-40% by 2040, with the amount of coal fired power stations under construction, apparently some 600 odd, thermal coal is going nowhere it seems for some time. That is not to say there won't be alternative fuel sources developed in this time (not talking about solar /wind) however it will take some time for these to be commercially viable.
