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'Fuel' is any combustible matter used to maintain fire, such as coal, wood, oil, or natural gas, in order to create heat or power. Fuel releases its energy either through chemical means, such as combustion, or nuclear means, such as nuclear fission or nuclear fusion. An important property of a useful fuel is that its energy can be stored to be released only when needed, and that the release is controlled in such a way that the energy can be harnessed to produce work.
All carbon-based life forms—from microorganisms to animals and humans—depend on and use fuels as their source of energy. Their cells engage in an enzyme-mediated chemical process called ''metabolism'' that converts energy from food or solar power into a form that can be used to sustain life. ^[1] Additionally, humans employ a variety of techniques to convert one form of energy into another, producing usable energy for purposes that go far beyond the energy needs of a human body. The application of energy released from fuels ranges from heat to cooking and from powering weapons to combustion and generation of electricity.

Contents

Energy sources

Chemical energy

Fossil fuels

Biofuels

Nuclear fuel

Fuel trade

Fuel use over time

See also

Footnotes

References

Further reading

Energy sources

All currently-known fuels ultimately derive their energy from a small number of sources. Much of the chemical energy produced by life forms, such as fossil fuels, is derived from the utilization of solar energy. This in turn is generated by the thermonuclear fusion process at the core of the Sun. Geothermal processes are driven by heat from the Earth's core, which is generated by the decay of radioactive compounds.^[2] These radioactive isotopes are produced through supernova explosions.
In the future, it is conceiveable that nuclear fusion facilities will be fueled by deuterium, an isotope of hydrogen. Most of the deuterium found in the universe was generated during the Big Bang.^[3] Fuel may also be produced by capturing the tidal energy of the orbiting Moon.
In stars that undergo nuclear fusion, the fuel consists of atomic nuclei that can release energy by the aborption of a proton or neutron. In most stars the fuel is provided by hydrogen, which can combine together to form helium through the proton-proton chain reaction or by the CNO cycle. When the hydrogen fuel is exhausted, nuclear fusion can continue with progressively heavier elements, although the net energy released is lower because of the smaller difference in nuclear binding energy. Once iron-56 or nickel-56 nuclei are produced, no further energy can be obtained by nuclear fusion as these have the highest nuclear binding energies.^[4]

Chemical energy

Chemical fuels are substances that generate energy by reacting with substances around them, most notably by the process of oxidization. These substances were the first fuels to be known and used by man and are still the primary type of fuel used today.

Fossil fuels

Main articles: Fossil fuel

Fossil fuels are hydrocarbons, primarily coal and petroleum (fuel oil or natural gas), formed from the fossilized remains of dead plants and animals^[5] by exposure to heat and pressure in the Earth's crust over hundreds of millions of years^[6]. In common parlance, the term fossil fuel also includes hydrocarbon-containing natural resources that are not derived entirely from biological sources, such as tar sands. These latter sources are properly known as ''mineral fuels''.
Modern large-scale industrial development is based on fossil fuel use, which has largely supplanted water-driven mills, as well as the combustion of wood or peat for heat. With global modernization in the 20th and 21st centuries, the growth in energy production from fossil fuels, especially gasoline derived from oil, is one of the causes of major regional and global conflicts and environmental issues. A global movement toward the generation of renewable energy is therefore under way to help meet the increased global energy needs.
The burning of fossil fuels by humans is the largest source of emissions of carbon dioxide, which is one of the greenhouse gases that enhances radiative forcing and contributes to global warming. The atmospheric concentration of CO₂, a greenhouse gas, is increasing, raising concerns that solar heat will be trapped and the average surface temperature of the Earth will rise in response.

Biofuels

Main articles: Biofuel

Biofuel can be broadly defined as solid, liquid, or gas fuel consisting of, or derived from biomass. Biomass can also be used directly for heating or power—known as ''biomass fuel''. The most common use for biofuels is in automotive transport (for example E10 fuel). Biofuel can be produced from any carbon source that can be replenished rapidly e.g. plants. Many different plants and plant-derived materials are used for biofuel manufacture.

Nuclear fuel

Main articles: Nuclear fuel

Nuclear fuel is any material that can be consumed to derive nuclear energy. By far the most common type of nuclear fuel is heavy fissile elements that can be made to undergo nuclear fission chain reactions in a nuclear fission reactor; ''nuclear fuel'' can refer to the material or to physical objects (for example fuel bundles composed of fuel rods) composed of the fuel material, perhaps mixed with structural, neutron moderating, or neutron reflecting materials. The most common fissile nuclear fuels are ²³⁵U and ²³⁹Pu, and the actions of mining, refining, purifying, using, and ultimately disposing of these elements together make up the nuclear fuel cycle, which is important for its relevance to nuclear power generation and nuclear weapons.

Fuel trade

World Bank reported that the USA was the top fuel importer in 2005 followed by the EU and Japan.

Fuel use over time

The first use of fuel was the combustion of wood or sticks by homo erectus near 2 million years ago.^[7] Throughout the majority of human history fuels derived from plants or animal fat were the only ones available for human use.

See also

★ List of energy topics

★ Alcohol fuel

★ Ammonia

★ Alternative fuels

★ Biomass

★ Biofuel

★ Combustion

★ Energy density

★ Fossil fuel

★ Fuel oil

★ Fuel poverty

★ Hydrocarbon

★ Liquid fuels

★ Oxidation

★ Propellant

★ Solid fuel

★ World energy resources and consumption

★ Fuel cell

Footnotes

1. "Metabolism," ''Encyclopaedia Britannica'', retrieved August 17, 2006.
2. Radioactive potassium may be major heat source in Earth's core
3. Tests of the Big Bang: The Light Elements
4. The atomic nuclide with the highest mean binding energy, , M. P., Fewell, American Journal of Physics, 1995
5. Canada's Fossil Fuel Dependency Dr. Irene Novaczek
6. Fossil fuel
7. The origin of human kind

References

★ Chemistry 1, Brian Ratcliff, Helen Eccles, David Johnson, John Nicholson, John Raffan. Cambridge University press 2000. ISBN 0 521 78778 5

Further reading

★ .

★ Council Directive 80/1268/EEC Fuel consumption of motor vehicles.