What Are the 3 Main Fossil Fuels?

Fossil fuels are formed from dead plant and animal tissue buried underground for millions of years, and is considered to be a nonrenewable source of energy. In 2007, the Energy Information Administration estimated that fossil fuels comprised 86.4 percent of the world's consumed energy. This amount was made up of three main fossil fuel sources: natural gas, coal, and crude oil.

Natural Gas

• In its raw state, natural gas consists of several gases, the main gas being methane. Natural gas accounts for around 24 percent of energy currently used in the world, and the U.S. produces around 25 percent of the world's natural gas supply. Although difficult to locate, natural gas deposits are identified by methods including the calculation of the gravitational pull of large sedimentary rocks buried in the earth's surface, and is often found alongside oil and coal deposits. Natural gas is considered nonrenewable, however methane recovered from landfills is classed as renewable as it originates from decaying refuse. Apart from an energy source, natural gas is an ingredient in a range of household products including laundry detergent, paint, ink and glue. Natural gas reserves in the U.S. are estimated to last for another 30 to 50 years.

Coal

• Coal is primarily used to generate electricity. Up to 93 percent of U.S.-mined coal is used for electricity. Coal is also utilized in iron and steel production. Coal is recovered either through surface or underground mining, with the former more popular in the U.S., as it is less expensive. There are four main types of coal: Lignite, Subbituminus, Bituminous, and Anthracite. The higher the carbon content of coal, the more energy it is capable of producing. Bituminous and Anthracite has the highest amounts of carbon, containing up to 86 and 97 percent respectively, however bituminous is more widely mined. It is estimated that the US has 262 billion tons of coal reserves, proposed to last for another 250 years.

Oil

• Oil is the most abundant fossil fuel. The majority of oil is refined and converted to gasoline, diesel and jet fuel. One gallon barrel of extracted crude oil can produce up to 44 gallons of petroleum products. Petroleum can be found in a wide range of everyday products, from CDs to bubble gum. As with all fossil fuels, its consumption has a negative impact on the environment, mainly due to air pollution when burned. Offshore oil drilling is particularly hazardous, as spills can be devastating to marine and human lives.