Fossil fuels are found deposited in rock formations. They were formed between 350 million and 50 million years ago, and so, although are technically renewable, it would take this long to remake them, which does not really help us today, it is due to the fact we need this long to make them that they are considered nonrenewable, and therefore will at some point run out. The processes by which they formed are not totally understood, other than that sediments buried decayed remains of ancient plants and/or animals. This is then effectively baked over millions of years under conditions of very high temperature and pressure, creating coal, oil, and natural gas, which consist of roughly 90% carbon
Fossil fuels are used widely in all forms of industry, in fact, coal, petroleum and gas provides over 90% of the energy used in most industrialized countries, compared with just 9% which hydroelectricity and nuclear power provide together.
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When looking at the properties of a good fuel, it is easy to see why fossil fuels are used:
* A fuel should react with an oxidiser to release large amounts of energy - carbon based fuels release over 30000 kJ per kilogram
* A fuel must be oxidised fairly easily, ignite quickly and sustain burning without further intervention - gaseous or easily vaporized fuels (such as oil) usually perform well here as the mix easily and continuously with oxygen which speeds up the reaction. Coal is often crushed to form small powders to make it ignite easier, however it is evident from steam the reliability of steam trains that carbon is easily burnt.
* A fuel should be readily available, in large quantities and at a reasonable price - initially this could be said to be true about fossil fuels, but now, as people become more aware of their cons, and of other fuels' pros, they are becoming more expensive and less available. Still, the price of oil is so heavily depended upon by the economy, that even the slight fluctuation in price can cause a country to go to war or a government to fall.
* A fuel should not burn to give products that are difficult to dispose of, unpleasant or harmful - fossil fuels definitely do not fall under this category, but the only fuel that does fall under this category is hydrogen.
* A fuel should be convenient to store and transport safely and with out loss - fossil fuels are the only type of fuel that people are currently comfortable with storing, hydrogen and methane are so flammable that people get nervous about using them for cars, and until a safe way of storing them is developed, fossil fuels will have to continue to be used
You may then wonder what the problem with fossil fuels is as they are obviously good at their job. What we must consider is the fact that they are non-renewable, and that we are consuming them at an incredible rate. It is predicted that most of the Earth's oil sources will be depleted over the century. Also, fossil fuels are used in many important chemical industries, such as making plastics, medicines, and solvents, and by burning them, we are decreasing our the feedstock for these vital products.
Fossil fuels such as oil are made into these products through a series of different processes. First the oil is fractionally distilled then the different sections join together to make polymers. These synthetic plastics and solvents are used largely in everyday life, such as polystyrene cups and PVC plastic.
Secondly, the burning of carbon based fuels produces large amounts of carbon dioxide that is one of the main contributors to the "greenhouse effect". There are such drastically high levels of carbon dioxide in the air that the only real solution would be to ban all use of fossil fuels, but countries have become so dependant upon them that is not feasible.
Thirdly, spillages of fossil fuels cause serious damages to local environments. When an oil tanker crashes, immense amounts of sea life and birds die, and the effects are disastrous.
Fourthly, inefficient burning of fossil fuels results in the production of carbon monoxide, which is a very harmful and poisonous gas. Inhalation of this gas is likely to cause death as it interferes with the transport of oxygen in the blood stream.
Fifthly, combustion of fossil fuels also produces gases such as nitrogen oxides, which cause acid rain.
In particular we can look at oil. Numerous countries' entire economies now rely on the price of oil, as their entire wealth is in the drilling, extracting, and trading in it. This is cause for great concern as oil is non-renewable, and we are consuming it so quickly, it will inevitably run out, and counties will no longer be able to rely on it.
We have seen in the past that countries' entire economies' have collapsed due to minor fluctuations in the oil market, therefore total collapse of the market would be devastating for many of the world's major and influential countries. Also, there would be immense amounts of job losses that would inevitably affect the society; this can be seen by looking at the destruction caused when the coalmines closed.
There are few ways which can be seen to overcome this imminent problem, however, one, most likely solution would be to investigate alternatives to fossil fuels, but all of the possible alternatives have their advantages and disadvantages which must be taken into account before making any changes.
* Biofuels (plants can be grown specifically for fuel or the production of fuel, such as wood or sugar cane. Biogas and biomass created by the growing and decaying of plants already produce usable fuel so this could easily be exploited to create a fuel source.) Advantages - renewable, reduces waste, simple technology. Disadvantages - not a large enough supply to totally replace fossil fuels
* Methanol CH3OH (this is a simple alcohol which can be made from methane.) Advantages - burns cleanly and completely Disadvantages - more toxic than ethanol, provides less energy per litre than petrol, can cause corrosion of car engines.
* Nuclear fission (energy is released when the nuclei of atoms of isotopes of uranium U-35 are split. The energy created can be used to heat water to turn steam turbines.) Advantages - no carbon, sulphur, or nitrogen oxides produces. Disadvantages - radioactive waste, safety systems needed are very expensive.
* Nuclear fusion (energy is released when deuterium and tritium "fuse" to create helium) Advantages - potentially almost limitless as an energy supply as the reactants come from water. Disadvantages - very costly, cannot currently be produced at economic rates.
* Moving air (wind turns windmills and wind turbines. Lots of research is already being carried out and soon may provide 10% of the UK's energy) Advantages - renewable, pollution and waste free, can be used in locality to where the energy is needed. Disadvantages - high initial expense, not reliable in calm weather, noise and visual environmental impact
* Moving water (Hydroelectricity - water stored behind dams can be released through turbines to generate electricity. Waves - The motion of waves is used to create oscillating motion. Tides - incoming tides in river estuaries fill up large water stores behind barrages, which is then released through turbines.) Advantages - renewable, predictable, pollution and waste free, large scale. Disadvantages - costly to install, environmental impact.
* Sunlight (Solar panels - collect solar heat and are used to heat water. Photovoltaic cells - convert light into electricity). Advantages - renewable, pollution and waste free. Disadvantages - Not good for places of low sunlight levels, high initial costs, not very practical for large-scale use.
* Geothermal energy (heat from rocks under the Earth's surface can be used to heat water which can, in turn, be used to heat houses). Advantages - practically unlimited. Disadvantages - not widely available, large initial costs
* Hydrogen (extracted from water by electrolysis, many things are capable of running on hydrogen). Advantages - no pollution. Disadvantages - people are nervous about using such a dangerously explosive gas, difficult to store and transport.
If some of these possibilities were researched further, they could replace fossil fuels and help many of the previously discussed issues.