Coal, oil, and natural gas are known as fossil fuels. These all contain hydrogen and carbon, which is why they are also known as hydrocarbons. These fuels are referred to as “fossils” because they are found in the ground and formed in the Earth’s crust millions of years ago. Fossil fuels are non-renewable and burning them for energy creates air pollution. Petrol, diesel, and kerosene are products made from fossil fuels.
How Coal was Formed
Coal has three major states: lignite, bituminous, and anthracite. Millions of years ago, huge amounts of plants scattered the earth on swamp grounds. When the plants die, they fall into these swamps. There was a lack of oxygen which caused them to not rot, and the dead plants piled up. With more and more soil and plants, thick layers were buried and compressed underground, forming peat, and with more compression, they formed lignite, a brown coal. Bituminous, soft coal is then formed as compression increases from above. Hard black coal, anthracite, is formed further underground with more compression over millions of years.
How Oil and Natural Gas are Formed
Oil was formed in much the same way as coal was: by compression from above for millions of years. Although oil was generally formed in the sea, billions of microscopic plants and animals died and sank to the seabed. They were buried and compressed for millions of years, forming oil, a thick black liquid. The decaying organisms give off gasses. Some of this gas also becomes trapped underground. Therefore, oil and natural gas are often found together. Natural gas is mainly a mixture of methane and ethane.
Mining and Drilling for Fossil Fuels
Open-cut (open-cast) or surface mining techniques are usually used to extract coal that is found close to the surface of the earth. Underground or deep mining methods are used for deeper coal deposits. Coal and rock are cut from the mines, separated, and then the coal is crushed and washed.
Pipes are drilled deep into the earth’s crust to extract oil and natural gas. Oil is trapped underground at high pressure and therefore when the drill hits the oil, it usually flows to the surface within the pipes. Water or gas may be forced into the wells if there is not enough natural pressure for the oil to flow through the pipes. Offshore production platforms or oil rigs are used to drill oil and gas from below the sea. Approximately 30% of oil production takes place in this manner. Oil which comes from the ground is called “crude oil”, and transformed at refineries into petroleum gases, petrol (gasoline), diesel oil, kerosene, lubricating oils and waxes.
Fossil Fuels as an Energy Source
Fossil fuels are popular and widely used because when they burn in the air, energy is released. This energy is used for cars, aircraft, and to supply electricity. Natural gas is used for cooking and heating. Some power stations burn huge amounts of coal to produce enough energy for the electricity supply to towns and cities. According to recent studies, based on current known deposits of oil and natural gas combined with current consumption, the world will run out of this fossil fuel within 100 years. Coal is expected to last 200 years at the current rate of mining and usage.
With the world’s diminishing supply of fossil fuels available, the world needs to be looking for renewable and alternative energy sources. New fuels are already being tested and used, as are new green ways to supply electricity. The reduction in the burning and use of coal, oil, and natural gas will also have a positive effect on the environment as they are believed to cause pollution.