Kohle, or coal, is a black or brownish-black sedimentary rock primarily composed of carbon. It forms from the remains of ancient plants that have been subjected to heat and pressure over millions of years. Coal is a significant source of energy and is used mainly for electricity generation and industrial processes. There are different types of coal, including anthracite, bituminous, sub-bituminous, and lignite, each varying in carbon content and energy output. While coal has been a crucial energy source, its combustion releases greenhouse gases, contributing to climate change, leading to a shift towards cleaner energy alternatives.