Coal, along with Oil and natural gas, are the traditional fossil fuels that have powered modern societies since the Industrial Revolution and remain the dominant world energy sources today. These fuels account for roughly 80 percent of world energy use, where the remainder comes from nuclear power and renewable fuels. Fossil fuels hold energy stored in plant tissues by photosynthesis millions of years ago. When these ancient plants and the animals that fed on them died, they were buried in sediments, where Earth's heat and compression from the weight of overlying rock eventually turned the deposits into coal, oil, and natural gas.
Coal, the first fossil fuel exploited by humans for energy on a large scale, is a carbonaceous rock formed from buried plants in ancient forests or swamps. These plant materials are initially converted to peat—a loose, brown, organically rich soil that itself is an important energy resource in some areas. As more rock layers press down on the buried deposits, geothermal energy heats the peat and reduces its oxygen and hydrogen content, converting it to coal. As materials go through this process, known as thermal maturation, their energy content by weight increases.
Renelux, in direct cooperation with large-scale mining companies, provides its clients with the following types of coal:
- Brown coal (lignite),
9 to 17 million British thermal units (Btu) per ton.
- Sub-bituminous coal
Energy value: 16 to 24 million Btu/ton
- Bituminous coal
Energy value: 19 to 30 million Btu/ton
Brown coal (lignite) is the first type of coal to form when plant matter is compacted. Sub-bituminous coal and bituminous coal are characteristically dark black and represent the most important coal grade for energy production (both direct heating and electricity generation) throughout the world.