Coal | National Geographic Society
· Peat is an important source of energy in many countries, including Ireland, Scotland, and Finland, where it is dehydrated and burned for heat. Lignite Lignite coal is the lowest rank of coal. It has carbonized past the point of being peat, but contains low amounts of energy—its carbon content is about 2535%. It comes from relatively young coal deposits, about 250 million years old. Lignite ...