Coal comes in many forms, but sulfur content is the most important distinction these days.  Low sulfur coal comes mainly from Montana and Wyoming, on mile-long trains traversing the countryside.  Conesville uses high-sulfur Ohio coal, which necessitates more pollution control.  Regardless, this shiny, jewel-like carbonized plant matter is the precious source of at least one third of all electricity generated in the United States and nearly all of the power we use in central Ohio.