Sometimes dismissed as the dirty fuel whose day is nearly over because of environmental concerns and ballooning output of cleaner-burning gas, coal is on a roll in Asia, with governments across the region ordering new coal-fired power stations.

Economic realities are outweighing worries about pollution, and coal's lower cost means its share of the energy mix in most Asian countries will rise for years, or even decades ahead. While investments in more expensive and cleaner power production are continuing, a greater emphasis...