Outline of energy

From Wikipedia, the free encyclopedia

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.[1][2] 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.

Forms of energy[edit]



List of common units for energy. Official or common symbol in brackets after name and exact or approximate value of unit in joule in brackets after description.

SI unit[edit]

  • Joule (J) – the SI-unit for energy. Also called newton meter, watt second, or coulomb volt.

Other metric units[edit]

  • Kilowatt-hour (kW·h) – corresponds to one kilowatt of power being used over a period of one hour (3.6 MJ).
  • Calorie (cal) – equal to the energy need to raise the temperature of one gram of water by one degree Celsius (~4.184 J).
  • Erg (erg) – unit of energy and mechanical work in the centimetre-gram-second (CGS) system of units (10−7 J).

Imperial or US Customary units[edit]

  • British thermal unit (BTU) – equal to the energy need to raise the temperature of one pound of water by one degree Fahrenheit (~1055 J).
  • Therm (thm) – unit of heat energy. In the US gas industry it is defined as exactly 100,000 BTU59 °F. It is approximately the heat equivalent of burning 100 cubic feet (2.8 m3) of natural gas (~105.5 MJ).
  • Quad – unit of energy equal to 1015 (a short-scale quadrillion) BTU.
  • Foot-pound (ft·lbf or ft·lbf) – unit of mechanical work, or energy, although in scientific fields one commonly uses joule (~1.356 J).

Other units[edit]

  • Electronvolt (eV) – the amount of energy gained by a single unbound electron when it falls through an electrostatic potential difference of one volt (~1.60 × 10−19 J).
  • Planck energy (EP) – natural unit of energy common in particle physics (~1.96×109 J).
  • Barrel of oil equivalent (BOE) – energy unit equal to the energy released when burning one barrel (159 litres) of oil (~6.12 GJ).
  • Tonne of oil equivalent (toe) – energy unit equal to the energy released when burning one tonne of oil (~42 GJ).

Related units and concepts[edit]

  • Volt
  • Ampere
  • Coulomb
  • Enthalpy
  • EU energy label
  • Fill factor – defined as the ratio of the maximum power (Vmp x Jmp) divided by the short-circuit current (Isc) and open-circuit voltage (Voc) in light current density – voltage (J-V) characteristics of solar cells.
  • Gigaton – Metric Unit of mass, equal to 1,000,000,000 (1 billion) metric tons, 1,000,000,000,000 (1 trillion) kilograms
    • Any of various units of energy, such as gigatons of TNT equivalent, gigatons of coal equivalent, gigatons petroleum equivalent.
  • Gray (unit) – (symbol: Gy), is the SI unit of energy for the absorbed dose of radiation. One gray is the absorption of one joule of radiation energy by one kilogram of matter. One gray equals 100 rad, an older unit.
  • Heat
  • Mass–energy equivalence – where mass has an energy equivalence, and energy has a mass equivalence
  • Megawatt
  • Net energy gain
  • Power factor – of an AC electric power system is defined as the ratio of the real power to the apparent power.

Energy industry[edit]

Energy industry

Energy infrastructure[edit]

See especially Category:Electric power and Category:Fuels for a large number of conventional energy related topics.

Energy applications[edit]

History of energy[edit]

History of energy

Physics of energy[edit]

Allegorical and esoteric[edit]

  • Energy (esotericism), invoked by spiritualists for alternative modes of healing the human body as well as a spirit that permeates all of reality.
  • Orgone, Wilhelm Reich discovered this energy and tried to use it to cure various physical ailments and control the weather.
  • Bioenergetic analysis, body-oriented Reichian psychotherapy
  • Qi, a concept from Oriental medicine that is sometimes translated as "energy" in the West.
  • Vitalism, often referred to as "energy"
  • Cold fusion, nuclear fusion at conditions close to room temperature.
  • Bubble fusion, also known as Sonofusion, energy from acoustic collapse of bubbles.
  • Water-fuelled car, powering a car using water as fuel.


Energy issues[edit]

Energy policies and use – national and international[edit]


Regional and national[edit]


Energy economics

Energy companies[edit]

Non-profit organizations[edit]

Industry associations[edit]

  • OPEC – Organization of Petroleum-exporting Countries
  • IEA – International Energy Agency
  • CAPP – Canadian Association of Petroleum Producers
  • World LP Gas Association – WLPGA



See also[edit]


  1. ^ "Retrieved on 2010-Dec-05". Faculty.clintoncc.suny.edu. Archived from the original on 2007-12-13. Retrieved 2010-12-12.
  2. ^ "Retrieved on 2010-Dec-05" (PDF). Archived (PDF) from the original on 2011-04-26. Retrieved 2010-12-12.
  3. ^ Jain, Mahesh C. (2009). "Fundamental forces and laws: a brief review". Textbook Of Engineering Physics, Part 1. PHI Learning Pvt. Ltd. p. 10. ISBN 9788120338623.
  4. ^ McCall, Robert P. (2010). "Energy, Work and Metabolism". Physics of the Human Body. JHU Press. p. 74. ISBN 978-0-8018-9455-8.

External links[edit]