Fossil Fuels
Fossil fuels are an important part of our energy consuming culture and at present are the main fuel source we have for running engines (such as in cars) and for electricity generation. Fossil fuels come from long-dead plant and animal matter that has been encased in the Earth's crust and has converted into products like oil, coal and methane after being left prone to intense heat and geological pressure for millions upon millions of years. Because fossil fuels take so long to form and require such specific conditions to germinate, they are an energy source which is deemed non-renewable - once we have run out we have no means of recreating the products artificially.
Effects Of Use
A further issue regarding the intensive use of fossil fuels is that they release huge quantities of carbon dioxide (as well as sulphuric and nitric acids, and even thorium and uranium) into the atmosphere when they are burned. Carbon dioxide is a major greenhouse gas and has been identified as the main cause of the current global warming crisis. As fossil fuels are still much cheaper and more readily available than alternative sources (like biogas and hydrogen for cars and hydro, solar and wind power for electricity) many people have no choice but to use these fuels for their everyday energy needs.
Extraction And Uses
There are three main categories of fossil fuel: oil, gas and coal. Petroleum, the fuel that runs the majority of our cars and trucks as well as being the main product used in many of our plastics and detergents, is derived from crude oil. Oil is also used to create diesel and kerosene (jet engine fuel), as well as fertilizers, pesticides and solvents.
In its most easily extractable form oil comes from reservoirs under the ground (or under the ocean bed), however it can also be found in sand reserves and in shale. Previously these latter forms of oil reserves have not been economically viable for tapping but recent price rises and increased demand have forced companies to investigate the possibility of more intensive oil mining.
The second type of fossil fuel, coal, is found in seams under the ground and is mined in much the same way as precious metals and stones are. Coal has been used for thousands of years as a source of heat, but has more recently been relied upon to generate steam that can be used to power turbines for electricity. Coal can also be converted into diesel and gasoline through liquefaction processes, or into gas through gasification.
The final type of fossil fuel, natural gas, is a product that is typically found alongside oil and coal or in isolated gas fields. Like coal and oil, natural gas can be burned in large furnaces to create heat for conversion (through steam) into electricity. Natural gas is also suitable for use in gas-fuelled cars, and is a major source of heating and cooking power in countries like the United Kingdom. Although natural gas cannot be replicated, improvements in biogas harvesting and purification have lead to many governments approving the use of biogas in the mains gas grid.