I decided to take an exploratory journey down that pathway, in effect following coal's carbon trail from cradle to grave. That's what took me to the Freedom Mine near Beulah, North Dakota. The mine serves as the fuel source for a sprawling complex that includes two large coal-based energy plants: the Dakota Gasification Company's Great Plains Synfuels Plant, which gasifies coal to produce a form of natural gas, and the Antelope Valley Station, a 900-MW traditional coal-fired plant.