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Welcome to Wikipedia's Energy portal, your gateway to energy. This portal is aimed at giving you access to all energy related topics in all of its forms.
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A plasma lamp, using electrical energy to create plasma, light, heat, movement and a faint sound

In physics, energy (from Ancient Greek ἐνέργεια (enérgeia) 'activity') is the quantitative property that is transferred to a body or to a physical system, recognizable in the performance of work and in the form of heat and light. Energy is a conserved quantity—the law of conservation of energy states that energy can be converted in form, but not created or destroyed. The unit of measurement for energy in the International System of Units (SI) is the joule (J).

Common forms of energy include the kinetic energy of a moving object, the potential energy stored by an object (for instance due to its position in a field), the elastic energy stored in a solid object, chemical energy associated with chemical reactions, the radiant energy carried by electromagnetic radiation, and the internal energy contained within a thermodynamic system. All living organisms constantly take in and release energy.

Due to mass–energy equivalence, any object that has mass when stationary (called rest mass) also has an equivalent amount of energy whose form is called rest energy, and any additional energy (of any form) acquired by the object above that rest energy will increase the object's total mass just as it increases its total energy.

Human civilization requires energy to function, which it gets from energy resources such as fossil fuels, nuclear fuel, or renewable energy. The Earth's climate and ecosystems processes are driven by the energy the planet receives from the Sun (although a small amount is also contributed by geothermal energy). (Full article...)

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A flexible-fuel vehicle (FFV) (or flex-fuel vehicle) is an alternative fuel vehicle with an internal combustion engine designed to run on more than one fuel, usually gasoline blended with either ethanol or methanol fuel, and both fuels are stored in the same common tank. The most common commercially available FFV in the world market is the ethanol flexible-fuel vehicle, with around 21 million automobiles, motorcycles and light duty trucks sold worldwide by mid 2010, and concentrated in four markets, Brazil (10.6 million), the United States (9.3 million), Canada (more than 600,000), and Europe, led by Sweden (199,000). Also a total of 183,375 flexible-fuel motorcycles were sold in Brazil in 2009. In addition to flex-fuel vehicles running with ethanol, in Europe and the US, mainly in California, there have been successful test programs with methanol flex-fuel vehicles, known as M85 flex-fuel vehicles.

Though technology exists to allow ethanol FFVs to run on any mixture of gasoline and ethanol, from pure gasoline up to 100% ethanol (E100), North American and European flex-fuel vehicles are optimized to run on a maximum blend of 15% gasoline with 85% anhydrous ethanol (called E85 fuel). This limit in the ethanol content is set to reduce ethanol emissions at low temperatures and to avoid cold starting problems during cold weather, at temperatures lower than 11 °C (52 °F). The alcohol content is reduced during the winter in regions where temperatures fall below 0 °C (32 °F) to a winter blend of E70 in the U.S. or to E75 in Sweden from November until March. Brazilian flex fuel vehicles are optimized to run on any mix of E20-E25 gasoline and up to 100% hydrous ethanol fuel (E100).

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The Geysers
The Geysers

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Michael Faraday (17911867), an English chemist and physicist, is credited with the discovery of electromagnetic induction, which formed the basis for exploiting electricity as a practical form of energy. His discovery paved the way for the development of generators, induction motors, transformers, and most other electrical machines.

In 1831, Faraday began his great series of experiments in which he discovered electromagnetic induction. He established that a changing magnetic field produces an electric field, a relation mathematically modelled by Faraday's law. Faraday later used the principle to construct the electric dynamo, the ancestor of modern power generators. He went on to investigate the fundamental nature of electricity, concluding in 1839 that, contrary to opinions at the time, only a single "electricity" exists, and the changing values of quantity and intensity (voltage and charge) would produce different groups of phenomena.

Some historians refer to Faraday as the best experimentalist in the history of science. Despite this his mathematical ability did not extend so far as trigonometry or any but the simplest algebra. He nevertheless possessed the ability to present his ideas in clear and simple language. During his lifetime, Faraday rejected a knighthood and twice refused to become President of the Royal Society.

In the news

9 September 2023 – Russian invasion of Ukraine
The International Atomic Energy Agency warns of a nuclear threat at the Zaporizhzhia Nuclear Power Plant after explosions were heard near the plant amidst the Ukrainian counteroffensive. (PBS News)

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