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Energy

In physics, energy is the quantitative property that must be transferred to an object in order to perform work on, or to heat, the object. 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 SI unit of energy is the joule, which is the energy transferred to an object by the work of moving it a distance of 1 metre against a force of 1 newton. Common forms of energy include the kinetic energy of a moving object, the potential energy stored by an objects position in a force field gravitational, electric or magnetic, the elastic energy stored by stretching solid objects, the chemical energy released when a fuel burns, the radiant energy carried by light, and the thermal energy due to an objects temperature. Mass and energy are closely related. 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 objects total mass just as it increases its total energy. For example, after heating an object, its increase in energy could be measured as a small increase in mass, with a sensitive enough scale. Living organisms require energy to stay alive, such as the energy humans get from food. Human civilization requires energy to function, which it gets from energy resources such as fossil fuels, nuclear fuel, or renewable energy. The processes of Earths climate and ecosystem are driven by the radiant energy Earth receives from the sun and the geothermal energy contained within the earth.

Index of energy articles

Activation energy - Alternative energy - Alternative energy indexes - American Museum of Science and Energy AMSE - Anisotropy energy - Atomic energy

Outline of energy

The following outline is provided as an overview of and topical guide to energy: Energy – in physics, this is an indirectly observed quantity often understood as the ability of a physical system to do work on other physical systems. Since work is defined as a force acting through a distance a length of space, energy is always equivalent to the ability to exert force a pull or a push against an object that is moving along a definite path of certain length.

Brown energy

Brown energy may refer to: The term "brown energy" has been coined as energy produced from polluting sources as a contrast to green energy from renewable, non-polluting sources. This term is controversial, as it can cause offense by associating polluting/bad resources with a color that people self-identify as. The term "grey energy" or "gray energy" has been used instead, including by the United Nations.

Drakoo wave energy converter

The Drakoo WEC does not fall under any of the usual wave energy converter classifications: its working principle, based on a twin-chamber oscillating water column system, is to transform waves into a continuous water flow which drives a hydro turbine generator.

Driving factors

In energy monitoring and targeting, a driving factor is something recurrent and measurable whose variation explains variation in energy consumption. The term independent variable is sometimes used as a synonym. One of the most common driving factors is the weather, expressed usually as heating or cooling degree days. In energy-intensive processes, production throughputs would usually be used. For electrical circuits feeding outdoor lighting, the number of hours of darkness can be employed. For a borehole pump, the quantity of water delivered would be used; and so on. What these examples all have in common is that on a weekly basis say numerical values can be recorded for each factor and one would expect particular streams of energy consumption to correlate with them either singly or in a multi-variate model. Correlation is arguably more important than causality. Variation in the driving factor merely has to explain variation in consumption; it does not necessarily have to cause it, although that will in most scenarios be the case. Driving factors differ from static factors, such as building floor areas, which determine energy consumption but change only rarely if at all.

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