Fuels

A fuel is a substance that is used for producing heat energy, either through the release of its chemical energy during burning or its nuclear energy by nuclear fission. The burning or combustion of fuels is used in many ways in homes and industry and in the generation of electricity. Fossil fuels (which are mostly hydrocarbons: compounds of hydrogen and carbon) such as coal, oil and gas are some of the most important and widely used fuels. As they burn, the hydrogen and carbon react with oxygen to produce water, carbon dioxide and heat. Fossil fuels are so called because they are just that, fossils. Millions of years ago, the Earth was a vastly different place, covered as it was with huge forests and oceans full of organisms. These plants and animals gradually died off and decayed. They were subsequently covered over by both the sea and sediment or by rocks. This caused the decaying matter to be compressed and, over millions of years, oil was formed from the sea creatures and coal from the plant life. Heat from fossil fuels can be utilized in very many ways. One of the main uses is for the generation of electricity.