Lignite, often referred to as brown coal, is a type of coal that is considered the lowest rank in the coal classification system. It is formed from compressed peat and has a high moisture content, which makes it less efficient as a fuel compared to higher-grade coals like bituminous coal or anthracite. Lignite is primarily used for electricity generation in power plants. This type of coal is typically found in large deposits and is mined in various regions around the world, including parts of Germany, the United States, and Australia. Due to its lower carbon content, lignite produces more carbon dioxide per unit of energy when burned, raising environmental concerns regarding its use as a fuel source.