Thermal coal for electrical power is the most straightforward to substitute, as there are other ways to make electricity: nuclear, gas, hydro, geothermal, solar, wind. (Taking into account economics, grid reliability/security, already large installed base of “young” coal-fired power plants). You haven’t mentioned steelmaking, a process for which substitutes for the use of metallurgical coal have a long way to go before they’d replace met coal.