List of energy topics
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The following outline is provided as an overview of and topical guide to energy:
Energy 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 ...
– in
physics Physics is the natural science that studies matter, its fundamental constituents, its motion and behavior through space and time, and the related entities of energy and force. "Physical science is that department of knowledge which ...
, this is an indirectly observed quantity often understood as the ability of a
physical system A physical system is a collection of physical objects. In physics, it is a portion of the physical universe chosen for analysis. Everything outside the system is known as the environment. The environment is ignored except for its effects on the ...
to do
work Work may refer to: * Work (human activity), intentional activity people perform to support themselves, others, or the community ** Manual labour, physical work done by humans ** House work, housework, or homemaking ** Working animal, an animal t ...
on other physical systems. Since work is defined as a
force In physics, a force is an influence that can change the motion of an object. A force can cause an object with mass to change its velocity (e.g. moving from a state of rest), i.e., to accelerate. Force can also be described intuitively as a ...
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

*
Chemical energy Chemical energy is the energy of chemical substances that is released when they undergo a chemical reaction and transform into other substances. Some examples of storage media of chemical energy include batteries, Schmidt-Rohr, K. (2018). "How ...
– energy contained in molecules *
Electrical energy Electrical energy is energy related to forces on electrically charged particles and the movement of electrically charged particles (often electrons in wires, but not always). This energy is supplied by the combination of electric current and elect ...
– energy from electric fields *Electro-centric energy – energy sustaining the continuous motion of free electron

*
Gravitational energy Gravitational energy or gravitational potential energy is the potential energy a massive object has in relation to another massive object due to gravity. It is the potential energy associated with the gravitational field, which is released (conver ...
– energy from gravitational fields *
Ionization energy Ionization, or Ionisation is the process by which an atom or a molecule acquires a negative or positive charge by gaining or losing electrons, often in conjunction with other chemical changes. The resulting electrically charged atom or molecule ...
energy that binds an electron to its atom or molecule *
Kinetic energy In physics, the kinetic energy of an object is the energy that it possesses due to its motion. It is defined as the work needed to accelerate a body of a given mass from rest to its stated velocity. Having gained this energy during its acce ...
– (), energy of the motion of a body * Magnetic energy – energy from magnetic fields *
Mechanical energy In physical sciences, mechanical energy is the sum of potential energy and kinetic energy. The principle of conservation of mechanical energy states that if an isolated system is subject only to conservative forces, then the mechanical energy is ...
– The sum of (usually
macroscopic The macroscopic scale is the length scale on which objects or phenomena are large enough to be visible with the naked eye, without magnifying optical instruments. It is the opposite of microscopic. Overview When applied to physical phenomena a ...
) kinetic and potential energies *
Mechanical wave In physics, a mechanical wave is a wave that is an oscillation of matter, and therefore transfers energy through a medium. While waves can move over long distances, the movement of the medium of transmission—the material—is limited. Therefor ...
– (), a form of mechanical energy propagated by a material's oscillations *
Nuclear binding energy Nuclear binding energy in experimental physics is the minimum energy that is required to disassemble the nucleus of an atom into its constituent protons and neutrons, known collectively as nucleons. The binding energy for stable nuclei is alway ...
energy that binds nucleons to form the
atomic nucleus The atomic nucleus is the small, dense region consisting of protons and neutrons at the center of an atom, discovered in 1911 by Ernest Rutherford based on the 1909 Geiger–Marsden gold foil experiment. After the discovery of the neutron ...
*
Potential energy In physics, potential energy is the energy held by an object because of its position relative to other objects, stresses within itself, its electric charge, or other factors. Common types of potential energy include the gravitational potenti ...
– energy possessed by a body by virtue of its position relative to others, stresses within itself, electric charge, and other factors. **
Elastic energy Elastic energy is the mechanical potential energy stored in the configuration of a material or physical system as it is subjected to elastic deformation by work performed upon it. Elastic energy occurs when objects are impermanently compressed, ...
– energy of deformation of a material (or its container) exhibiting a restorative force **
Gravitational energy Gravitational energy or gravitational potential energy is the potential energy a massive object has in relation to another massive object due to gravity. It is the potential energy associated with the gravitational field, which is released (conver ...
– potential energy associated with a gravitational field. ** Nuclear potential energy *
Radiant energy Radiant may refer to: Computers, software, and video games * Radiant (software), a content management system * GtkRadiant, a level editor created by id Software for their games * Radiant AI, a technology developed by Bethesda Softworks for ''Th ...
– (), energy of
electromagnetic radiation In physics, electromagnetic radiation (EMR) consists of waves of the electromagnetic (EM) field, which propagate through space and carry momentum and electromagnetic radiant energy. It includes radio waves, microwaves, infrared, (visib ...
including
light Light or visible light is electromagnetic radiation that can be perceived by the human eye. Visible light is usually defined as having wavelengths in the range of 400–700 nanometres (nm), corresponding to frequencies of 750–420 t ...
and of
gravitational radiation Gravitational waves are waves of the intensity of gravity generated by the accelerated masses of an orbital binary system that propagate as waves outward from their source at the speed of light. They were first proposed by Oliver Heaviside in 1 ...
*
Rest energy The invariant mass, rest mass, intrinsic mass, proper mass, or in the case of bound systems simply mass, is the portion of the total mass of an object or system of objects that is independent of the overall motion of the system. More precisely, ...
– () given by , where is an object's
rest mass The invariant mass, rest mass, intrinsic mass, proper mass, or in the case of bound systems simply mass, is the portion of the total mass of an object or system of objects that is independent of the overall motion of the system. More precisely, i ...
*
Surface energy In surface science, surface free energy (also interfacial free energy or surface energy) quantifies the disruption of intermolecular bonds that occurs when a surface is created. In solid-state physics, surfaces must be intrinsically less ener ...
*
Thermal energy The term "thermal energy" is used loosely in various contexts in physics and engineering. It can refer to several different well-defined physical concepts. These include the internal energy or enthalpy of a body of matter and radiation; heat, de ...
– a
microscopic The microscopic scale () is the scale of objects and events smaller than those that can easily be seen by the naked eye, requiring a lens or microscope to see them clearly. In physics, the microscopic scale is sometimes regarded as the scale be ...
, disordered equivalent of mechanical energy **
Heat In thermodynamics, heat is defined as the form of energy crossing the boundary of a thermodynamic system by virtue of a temperature difference across the boundary. A thermodynamic system does not ''contain'' heat. Nevertheless, the term is ...
– an amount of
thermal energy The term "thermal energy" is used loosely in various contexts in physics and engineering. It can refer to several different well-defined physical concepts. These include the internal energy or enthalpy of a body of matter and radiation; heat, de ...
being transferred (in a given process) in the direction of decreasing temperature *
Work (physics) In physics, work is the energy transferred to or from an object via the application of force along a displacement. In its simplest form, for a constant force aligned with the direction of motion, the work equals the product of the force stre ...
– an amount of energy being
energy transfer 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 ...
red in a given process due to displacement in the direction of an applied
force In physics, a force is an influence that can change the motion of an object. A force can cause an object with mass to change its velocity (e.g. moving from a state of rest), i.e., to accelerate. Force can also be described intuitively as a ...


Measurement


Units

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

*
Joule The joule ( , ; symbol: J) is the unit of energy in the International System of Units (SI). It is equal to the amount of work done when a force of 1 newton displaces a mass through a distance of 1 metre in the direction of the force appli ...
(J) – the SI-unit for energy. Also called newton meter, watt second, or coulomb volt.


Other metric units

*
Kilowatt-hour A kilowatt-hour ( unit symbol: kW⋅h or kW h; commonly written as kWh) is a unit of energy: one kilowatt of power for one hour. In terms of SI derived units with special names, it equals 3.6 megajoules (MJ). Kilowatt-hours are a common b ...
(kW·h) – corresponds to one
kilowatt The watt (symbol: W) is the unit of power or radiant flux in the International System of Units (SI), equal to 1 joule per second or 1 kg⋅m2⋅s−3. It is used to quantify the rate of energy transfer. The watt is named after James ...
of power being used over a period of one hour (). *
Calorie The calorie is a unit of energy. For historical reasons, two main definitions of "calorie" are in wide use. The large calorie, food calorie, or kilogram calorie was originally defined as the amount of heat needed to raise the temperature of o ...
(cal) – equal to the energy need to raise the temperature of one
gram The gram (originally gramme; SI unit symbol g) is a unit of mass in the International System of Units (SI) equal to one one thousandth of a kilogram. Originally defined as of 1795 as "the absolute weight of a volume of pure water equal to th ...
of water by one
degree Celsius Degree may refer to: As a unit of measurement * Degree (angle), a unit of angle measurement ** Degree of geographical latitude ** Degree of geographical longitude * Degree symbol (°), a notation used in science, engineering, and mathematics ...
(~4.184 J). *
Erg The erg is a unit of energy equal to 10−7joules (100 nJ). It originated in the Centimetre–gram–second system of units (CGS). It has the symbol ''erg''. The erg is not an SI unit. Its name is derived from (), a Greek word meaning 'work' o ...
(erg) – unit of energy and mechanical work in the centimetre-gram-second (CGS) system of units (10−7 J).


Imperial or US Customary units

*
British thermal unit The British thermal unit (BTU or Btu) is a unit of heat; it is defined as the amount of heat required to raise the temperature of one pound of water by one degree Fahrenheit. It is also part of the United States customary units. The modern SI ...
(BTU) – equal to the energy need to raise the temperature of one pound of water by one degree
Fahrenheit The Fahrenheit scale () is a temperature scale based on one proposed in 1724 by the physicist Daniel Gabriel Fahrenheit (1686–1736). It uses the degree Fahrenheit (symbol: °F) as the unit. Several accounts of how he originally defined hi ...
(~1055 J). *
Therm The therm (symbol, thm) is a non- SI unit of heat energy equal to 100,000 British thermal units (BTU), and approximately megajoules, kilowatt-hours, kilocalories and thermies. One therm is the energy content of approximately of natural gas a ...
(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 of natural gas (~105.5 MJ). *
Quad Quad as a word or prefix usually means 'four'. It may refer to: Government * Quadrilateral Security Dialogue, a strategic security dialogue between Australia, India, Japan, and the United States * Quadrilateral group, an informal group which inc ...
– unit of energy equal to 1015 (a
short-scale The long and short scales are two of several naming systems for integer powers of ten which use some of the same terms for different magnitudes. For whole numbers smaller than 1,000,000,000 (109), such as one thousand or one million, the ...
quadrillion) BTU. *
Foot-pound The foot-pound force (symbol: ft⋅lbf, ft⋅lbf, or ft⋅lb ) is a unit of work or energy in the engineering and gravitational systems in United States customary and imperial units of measure. It is the energy transferred upon applying a fo ...
(ft·lbf or ft·lbf) – unit of mechanical work, or energy, although in scientific fields one commonly uses joule (~1.356 J).


Other units

*
Electronvolt In physics, an electronvolt (symbol eV, also written electron-volt and electron volt) is the measure of an amount of kinetic energy gained by a single electron accelerating from rest through an electric potential difference of one volt in vacu ...
(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 () – natural unit of energy common in
particle physics Particle physics or high energy physics is the study of fundamental particles and forces that constitute matter and radiation. The fundamental particles in the universe are classified in the Standard Model as fermions (matter particles) an ...
(~). *
Barrel of oil equivalent The barrel of oil equivalent (BOE) is a unit of energy based on the approximate energy released by burning one barrel (, or ) of crude oil. The BOE is used by oil and gas companies in their financial statements as a way of combining oil and nat ...
(BOE) – energy unit equal to the energy released when burning one
barrel A barrel or cask is a hollow cylindrical container with a bulging center, longer than it is wide. They are traditionally made of wooden staves and bound by wooden or metal hoops. The word vat is often used for large containers for liquids, ...
() of oil (~6.12 GJ). *
Tonne of oil equivalent The tonne of oil equivalent (toe) is a unit of energy defined as the amount of energy released by burning one tonne of crude oil. It is approximately 42 gigajoules or 11.630 megawatt-hours, although as different crude oils have different calorifi ...
(toe) – energy unit equal to the energy released when burning one
tonne The tonne ( or ; symbol: t) is a unit of mass equal to 1000  kilograms. It is a non-SI unit accepted for use with SI. It is also referred to as a metric ton to distinguish it from the non-metric units of the short ton ( United State ...
of oil (~42 GJ).


Related units and concepts

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Volt The volt (symbol: V) is the unit of electric potential, electric potential difference (voltage), and electromotive force in the International System of Units (SI). It is named after the Italian physicist Alessandro Volta (1745–1827). Defin ...
*
Ampere The ampere (, ; symbol: A), often shortened to amp,SI supports only the use of symbols and deprecates the use of abbreviations for units. is the unit of electric current in the International System of Units (SI). One ampere is equal to elect ...
*
Coulomb The coulomb (symbol: C) is the unit of electric charge in the International System of Units (SI). In the present version of the SI it is equal to the electric charge delivered by a 1 ampere constant current in 1 second and to elementary char ...
*
Enthalpy Enthalpy , a property of a thermodynamic system, is the sum of the system's internal energy and the product of its pressure and volume. It is a state function used in many measurements in chemical, biological, and physical systems at a constant ...
*
EU energy label EU Directive 92/75/EC established an energy consumption labelling scheme. The directive was implemented by several other directives thus most white goods, light bulb packaging and cars must have an EU Energy Label clearly displayed when offered ...
* 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 ''Gigaton'' is the eleventh studio album by American rock band Pearl Jam, released March 27, 2020. It was preceded by the singles "Dance of the Clairvoyants", "Superblood Wolfmoon" and "Quick Escape". It is the band's first studio album in six ...
– 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) The gray (symbol: Gy) is the unit of ionizing radiation dose in the International System of Units (SI), defined as the absorption of one joule of radiation energy per kilogram of matter. It is used as a unit of the radiation quantity absorbed do ...
– (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 In thermodynamics, heat is defined as the form of energy crossing the boundary of a thermodynamic system by virtue of a temperature difference across the boundary. A thermodynamic system does not ''contain'' heat. Nevertheless, the term is ...
* Mass-energy equivalence – where mass has an energy equivalence, and energy has a mass equivalence *
Megawatt The watt (symbol: W) is the unit of power or radiant flux in the International System of Units (SI), equal to 1 joule per second or 1 kg⋅m2⋅s−3. It is used to quantify the rate of energy transfer. The watt is named after James ...
* Net energy gain *
Power factor In electrical engineering, the power factor of an AC power system is defined as the ratio of the ''real power'' absorbed by the load to the '' apparent power'' flowing in the circuit. Real power is the average of the instantaneous product of v ...
– of an AC electric power system is defined as the ratio of the real power to the apparent power.


Energy industry

Energy industry The energy industry is the totality of all of the industries involved in the production and sale of energy, including fuel extraction, manufacturing, refining and distribution. Modern society consumes large amounts of fuel, and the energy indus ...
*
Worldwide energy supply World energy supply and consumption is global production and preparation of fuel, generation of electricity, energy transport, and energy consumption. It is a basic part of economic activity. It includes heat, but not energy from food. This art ...
, outline by country/region *
World energy resources and consumption World energy supply and consumption is global production and preparation of fuel, generation of electricity, energy transport, and energy consumption. It is a basic part of economic activity. It includes heat, but not energy from food. This art ...
*
List of energy resources These are modes of energy production, energy storage, or energy conservation, listed alphabetically. Note that not all sources are accepted as legitimate or have been proven to be tappable. *Atomic energy *Banki turbine *Battery (electricity) * ...
, substances like fuels, petroleum products and electricity *
Energy crisis An energy crisis or energy shortage is any significant bottleneck in the supply of energy resources to an economy. In literature, it often refers to one of the energy sources used at a certain time and place, in particular, those that supply n ...
, the need to conserve energy resources *
Energy development Energy development is the field of activities focused on obtaining sources of energy from natural resources. These activities include production of renewable, nuclear, and fossil fuel derived sources of energy, and for the recovery and reuse ...
, development of energy resources — ongoing effort to provide abundant and accessible energy, through knowledge, skills and construction *
Embodied energy Embodied energy is the sum of all the energy required to produce any goods or services, considered as if that energy was incorporated or 'embodied' in the product itself. The concept can be useful in determining the effectiveness of energy-produ ...
, the sum total of energy expended to deliver a good or service as it travels through the economy *
Energy conservation Energy conservation is the effort to reduce wasteful energy consumption by using fewer energy services. This can be done by using energy more effectively (using less energy for continuous service) or changing one's behavior to use less service (f ...
, tips for conserving energy resources *
Energy economics Energy economics is a broad scientific subject area which includes topics related to supply and use of energy in societies. Considering the cost of energy services and associated value gives economic meaning to the efficiency at which energ ...
, as the foundation of other relationships *
Energy policy Energy policy is the manner in which a given entity (often governmental) has decided to address issues of energy development including energy conversion, distribution and use as well as reduction of greenhouse gas emissions in order to contr ...
, government policies and plans for energy supply *
Energy storage Energy storage is the capture of energy produced at one time for use at a later time to reduce imbalances between energy demand and energy production. A device that stores energy is generally called an accumulator or battery. Energy comes in ...
, methods commonly used to store energy resources for later use *
Energy system An energy system is a system primarily designed to supply energy-services to end-users. The intent behind energy systems is to minimise energy losses to a negligible level, as well as to ensure the efficient use of energy. The IPCC Fifth As ...
, an interpretation the energy sector in system terms *
Biosphere The biosphere (from Greek βίος ''bíos'' "life" and σφαῖρα ''sphaira'' "sphere"), also known as the ecosphere (from Greek οἶκος ''oîkos'' "environment" and σφαῖρα), is the worldwide sum of all ecosystems. It can also ...
*
Ecological energetics Energy flow is the flow of energy through living things within an ecosystem. All living organisms can be organized into producers and consumers, and those producers and consumers can further be organized into a food chain. Each of the levels wi ...
*
Ecology Ecology () is the study of the relationships between living organisms, including humans, and their physical environment. Ecology considers organisms at the individual, population, community, ecosystem, and biosphere level. Ecology overl ...
*
Energy balance Energy balance may refer to: * Earth's energy balance, the relationship between incoming solar radiation, outgoing radiation of all types, and global temperature change. * Energy accounting, a system used within industry, where measuring and anal ...
*
Earth Day Earth Day is an annual event on April 22 to demonstrate support for environmental protection. First held on April 22, 1970, it now includes a wide range of events coordinated globally by EarthDay.org (formerly Earth Day Network) including 1 b ...
* Energy speculation *
Free energy suppression Free energy suppression (or new energy suppression) is a conspiracy theory that technologically viable, pollution-free, no-cost energy sources are being suppressed by government, corporations, or advocacy groups. Devices allegedly suppressed inc ...
* Future energy development – Provides a general overview of future energy development. *
History of perpetual motion machines The history of perpetual motion machines dates at least back to the Middle Ages. For millennia, it was not clear whether perpetual motion devices were possible or not, but modern theories of thermodynamics have shown that they are impossible. ...
*
Hubbert peak theory The Hubbert peak theory says that for any given geographical area, from an individual oil-producing region to the planet as a whole, the rate of petroleum production tends to follow a bell-shaped curve. It is one of the primary theories on peak ...
, also known as
peak oil Peak oil is the hypothetical point in time when the maximum rate of global oil production is reached, after which it is argued that production will begin an irreversible decline. It is related to the distinct concept of oil depletion; whil ...
– the theory that world oil production will peak (or has peaked), and will then rapidly decline, with a corresponding rapid increase in prices. *
Primary production In ecology, primary production is the synthesis of organic compounds from atmospheric or aqueous carbon dioxide. It principally occurs through the process of photosynthesis, which uses light as its source of energy, but it also occurs through ...
* Power harvesting *
Renewable energy development Renewable energy commercialization involves the deployment of three generations of renewable energy technologies dating back more than 100 years. First-generation technologies, which are already mature and economically competitive, include ...


Energy infrastructure

See especially :Electric power and :Fuels for a large number of conventional energy related topics. *
Energy storage Energy storage is the capture of energy produced at one time for use at a later time to reduce imbalances between energy demand and energy production. A device that stores energy is generally called an accumulator or battery. Energy comes in ...
*
Electricity generation Electricity generation is the process of generating electric power from sources of primary energy. For utilities in the electric power industry, it is the stage prior to its delivery ( transmission, distribution, etc.) to end users or its s ...
*
Electricity retailing Electricity retailing is the final sale of electricity from generation to the end-use consumer. This is the fourth major step in the electricity delivery process, which also includes generation, transmission and distribution. Beginnings Electric ...
*
Grid energy storage Grid energy storage (also called large-scale energy storage) is a collection of methods used for energy storage on a large scale within an electrical power grid. Electrical energy is stored during times when electricity is plentiful and inex ...
*
Liquified natural gas Liquefied natural gas (LNG) is natural gas (predominantly methane, CH4, with some mixture of ethane, C2H6) that has been cooled down to liquid form for ease and safety of non-pressurized storage or transport. It takes up about 1/600th the volu ...
*
Microwave power transmission Wireless power transfer (WPT), wireless power transmission, wireless energy transmission (WET), or electromagnetic power transfer is the transmission of electrical energy without wires as a physical link. In a wireless power transmission system ...
*
Power station A power station, also referred to as a power plant and sometimes generating station or generating plant, is an industrial facility for the generation of electric power. Power stations are generally connected to an electrical grid. Many ...
*
Power supply A power supply is an electrical device that supplies electric power to an electrical load. The main purpose of a power supply is to convert electric current from a source to the correct voltage, current, and frequency to power the load. As ...
*
Power transmission Power transmission is the movement of energy from its place of generation to a location where it is applied to perform useful work. Power is defined formally as units of energy per unit time. In SI units: :\text = \frac = \frac Since the develo ...
*
Underground power station An underground power station is a type of hydroelectric power station constructed by excavating the major components (e.g. machine hall, penstocks, and tailrace) from rock, rather than the more common surface-based construction methods. One or mor ...


Energy applications

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Biofuel Biofuel is a fuel that is produced over a short time span from biomass, rather than by the very slow natural processes involved in the formation of fossil fuels, such as oil. According to the United States Energy Information Administration ...
*
Distributed generation Distributed generation, also distributed energy, on-site generation (OSG), or district/decentralized energy, is electrical generation and storage performed by a variety of small, grid-connected or distribution system-connected devices referred to ...
*
Electric vehicle An electric vehicle (EV) is a vehicle that uses one or more electric motors for propulsion. It can be powered by a collector system, with electricity from extravehicular sources, or it can be powered autonomously by a battery (sometimes ch ...
*
Hybrid vehicle A hybrid vehicle is one that uses two or more distinct types of power, such as submarines that use diesel when surfaced and batteries when submerged. Other means to store energy include pressurized fluid in hydraulic hybrids. The basic princi ...
*
Hydrogen vehicle A hydrogen vehicle is a vehicle that uses hydrogen fuel for motive power. Hydrogen vehicles include hydrogen-fueled space rockets, as well as ships and aircraft. Power is generated by converting the chemical energy of hydrogen to mechanical en ...
*
Passive solar building design In passive solar building design, windows, walls, and floors are made to collect, store, reflect, and distribute solar energy, in the form of heat in the winter and reject solar heat in the summer. This is called passive solar design because, unli ...
*
Steam engine A steam engine is a heat engine that performs mechanical work using steam as its working fluid. The steam engine uses the force produced by steam pressure to push a piston back and forth inside a cylinder. This pushing force can be ...


History of energy

History of energy * History of the energy industry ** History of coal ***
History of coal mining The history of coal mining goes back thousands of years, with early mines documented in ancient China, the Roman Empire and other early historical economies. It became important in the Industrial Revolution of the 19th and 20th centuries, when it wa ...
** ***
History of electromagnetic theory The history of electromagnetic theory begins with ancient measures to understand atmospheric electricity, in particular lightning. People then had little understanding of electricity, and were unable to explain the phenomena. Scientific understan ...
*** History of electrical engineering ***
History of electronic engineering This article details the history of electronic engineering. ''Chambers Twentieth Century Dictionary'' (1972) defines electronics as "The science and technology of the conduction of electricity in a vacuum, a gas, or a semiconductor, and devices ba ...
*** History of the electric generator *** History of the electric motor ****
Timeline of the electric motor Electric motors have a long history going back to the early nineteenth century. Nineteenth century Twentieth century References {{electric motor Electric motors ...
*** History of electric power transmission ** History of nuclear power **
History of petroleum While the local use of oil goes back many centuries, the modern petroleum industry along with its outputs and modern applications are of a recent origin. Petroleum's status as a key component of politics, society, and technology has its roots in t ...
***
History of the petroleum industry While the local use of oil goes back many centuries, the modern petroleum industry along with its outputs and modern applications are of a recent origin. Petroleum's status as a key component of politics, society, and technology has its roots in t ...
** History of renewable energy *** History of alternative energy *** History of hydropower *** History of solar cells ****
Growth of photovoltaics Worldwide growth of photovoltaics has been close to exponential between 1992 and 2018. During this period of time, photovoltaics (PV), also known as solar PV, evolved from a niche market of small-scale applications to a mainstream electricit ...
*** History of sustainability ***
History of wind power Wind power has been used as long as humans have put sails into the wind. For more than two millennia wind-powered machines have ground grain and pumped water. Wind power was widely available and not confined to the banks of fast-flowing streams ...
***
Timeline of sustainable energy research 2020–present Timeline of notable events in the research and development of sustainable energy including renewable energy, solar energy and nuclear fusion energy, particularly for ways that are sustainable within the Earth system. Events currently no ...
** History of the steam engine ***
Steam power during the Industrial Revolution Improvements to the steam engine were some of the most important technologies of the Industrial Revolution, although steam did not replace water power in importance in Britain until after the Industrial Revolution. From Englishman Thomas Newcome ...


Physics of energy

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Energy 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 ...
*
Activation energy In chemistry and physics, activation energy is the minimum amount of energy that must be provided for compounds to result in a chemical reaction. The activation energy (''E''a) of a reaction is measured in joules per mole (J/mol), kilojoules p ...
, explains the differences in the speeds of various chemical reactions *
Bioenergetics Bioenergetics is a field in biochemistry and cell biology that concerns energy flow through living systems. This is an active area of biological research that includes the study of the transformation of energy in living organisms and the study of ...
* Chemical energetics * Energy in physical cosmology * Energy in Earth science that is responsible for the macroscopic transformations on the planet Earth *
Electricity Electricity is the set of physical phenomena associated with the presence and motion of matter that has a property of electric charge. Electricity is related to magnetism, both being part of the phenomenon of electromagnetism, as describe ...
*
Exergy In thermodynamics, the exergy of a system is the maximum useful work possible during a process that brings the system into equilibrium with a heat reservoir, reaching maximum entropy. When the surroundings are the reservoir, exergy is the pot ...
*
Green energy Energy is sustainable if it "meets the needs of the present without compromising the ability of future generations to meet their own needs". Most definitions of sustainable energy include considerations of environmental aspects such as greenh ...
*
Orders of magnitude (energy) This list compares various energies in joules (J), organized by order of magnitude. Below 1 J 1 to 105 J 106 to 1011 J 1012 to 1017 J 1018 to 1023 J Over 1023 J } , - , 1050 , , ≳1050 J , Upper limit of 'apparent'/isotropic energy ...
, list describing various energy levels between 10−31
joule The joule ( , ; symbol: J) is the unit of energy in the International System of Units (SI). It is equal to the amount of work done when a force of 1 newton displaces a mass through a distance of 1 metre in the direction of the force appli ...
s and 1070 joules *
Thermodynamics Thermodynamics is a branch of physics that deals with heat, work, and temperature, and their relation to energy, entropy, and the physical properties of matter and radiation. The behavior of these quantities is governed by the four laws ...
*
Perpetual motion Perpetual motion is the motion of bodies that continues forever in an unperturbed system. A perpetual motion machine is a hypothetical machine that can do work infinitely without an external energy source. This kind of machine is impossible, a ...
*
Heat In thermodynamics, heat is defined as the form of energy crossing the boundary of a thermodynamic system by virtue of a temperature difference across the boundary. A thermodynamic system does not ''contain'' heat. Nevertheless, the term is ...
* History of energy *
Forms of energy 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 ...
, the forms in which energy can be defined *
Energy transformation Energy transformation, also known as energy conversion, is the process of changing energy from one form to another. In physics, energy is a quantity that provides the capacity to perform work or moving, (e.g. Lifting an object) or provides he ...
, relating to energy's changes from one form to another. * Energy (signal processing), the inner product of a signal in the time domain * Energy density spectrum, relating to the distribution of signal energy over frequencies. *
Potential energy In physics, potential energy is the energy held by an object because of its position relative to other objects, stresses within itself, its electric charge, or other factors. Common types of potential energy include the gravitational potenti ...
, the form of energy that is due to position of an object *
Kinetic energy In physics, the kinetic energy of an object is the energy that it possesses due to its motion. It is defined as the work needed to accelerate a body of a given mass from rest to its stated velocity. Having gained this energy during its acce ...
, the form of energy as a consequence of the motion of an object or its constituents *
Mechanical energy In physical sciences, mechanical energy is the sum of potential energy and kinetic energy. The principle of conservation of mechanical energy states that if an isolated system is subject only to conservative forces, then the mechanical energy is ...
, the potential energy and kinetic energy present in the components of a mechanical system *
Binding energy In physics and chemistry, binding energy is the smallest amount of energy required to remove a particle from a system of particles or to disassemble a system of particles into individual parts. In the former meaning the term is predominantly use ...
, a concept explaining how the constituents of atoms or molecules are bound together *
Bond energy In chemistry, bond energy (''BE''), also called the mean bond enthalpy or average bond enthalpy is the measure of bond strength in a chemical bond. IUPAC defines bond energy as the average value of the gas-phase bond-dissociation energy (usually ...
, a measure of the strength of a chemical bond * Nuclear energy, energy that is the consequence of decomposition or combination of atomic nuclei *
Osmotic power Osmotic power, salinity gradient power or blue energy is the energy available from the difference in the salt concentration between seawater and river water. Two practical methods for this are reverse electrodialysis (RED) and pressure retarde ...
, also salinity gradient power or blue energy, the energy available from the difference in the salt concentration between seawater and river water *
Gibbs free energy In thermodynamics, the Gibbs free energy (or Gibbs energy; symbol G) is a thermodynamic potential that can be used to calculate the maximum amount of work that may be performed by a thermodynamically closed system at constant temperature an ...
, a related concept in chemical thermodynamics that incorporates entropy considerations *
Helmholtz free energy In thermodynamics, the Helmholtz free energy (or Helmholtz energy) is a thermodynamic potential that measures the useful work obtainable from a closed thermodynamic system at a constant temperature (isothermal). The change in the Helmholtz en ...
, a thermodynamic potential that measures the "useful" work obtainable from a closed thermodynamic system at a constant temperature, useful for studying explosive chemical reactions *
Elastic energy Elastic energy is the mechanical potential energy stored in the configuration of a material or physical system as it is subjected to elastic deformation by work performed upon it. Elastic energy occurs when objects are impermanently compressed, ...
, which causes or is released by the elastic distortion of a solid or a fluid *
Ionization energy Ionization, or Ionisation is the process by which an atom or a molecule acquires a negative or positive charge by gaining or losing electrons, often in conjunction with other chemical changes. The resulting electrically charged atom or molecule ...
(IE), the energy required to strip an atom of an electron *
Interaction energy In physics, interaction energy is the contribution to the total energy that is caused by an interaction between the objects being considered. The interaction energy usually depends on the relative position of the objects. For example, Q_1 Q_2 / ( ...
, the contribution to the total energy that is a result of interaction between the objects being considered *
Internal energy The internal energy of a thermodynamic system is the total energy contained within it. It is the energy necessary to create or prepare the system in its given internal state, and includes the contributions of potential energy and internal kinet ...
(abbreviated E or U), the total kinetic energy due to the motion of molecules (translational, rotational, vibrational) and the total potential energy associated with the vibrational and electric energy of atoms within molecules. * Negative energy *
Energy conversion Energy transformation, also known as energy conversion, is the process of changing energy from one form to another. In physics, energy is a quantity that provides the capacity to perform work or moving, (e.g. Lifting an object) or provides heat ...
, process of converting energy from one form to another *
Dark energy In physical cosmology and astronomy, dark energy is an unknown form of energy that affects the universe on the largest scales. The first observational evidence for its existence came from measurements of supernovas, which showed that the univ ...
, used to explain some cosmological phenomena *
Energy quality Energy quality is a measure of the ease with which a form of energy can be converted to useful work or to another form of energy: i.e. its content of thermodynamic free energy. A high quality form of energy has a high content of thermodynamic f ...
, empirical experience of the characteristics of different energy forms as they flow and transform *
Energy density In physics, energy density is the amount of energy stored in a given system or region of space per unit volume. It is sometimes confused with energy per unit mass which is properly called specific energy or . Often only the ''useful'' or extrac ...
, amount of energy stored in a given system or region of space per unit volume, or per unit mass * Energy flow, flow of energy in an ecosystem through food chains * Energetics (disambiguation), the scientific study of energy in general *
Stress–energy tensor The stress–energy tensor, sometimes called the stress–energy–momentum tensor or the energy–momentum tensor, is a tensor physical quantity that describes the density and flux of energy and momentum in spacetime, generalizing the str ...
, the density and flux of energy and momentum in space-time; the source of the gravitational field in general relativity *
Food energy Food energy is chemical energy that animals (including humans) derive from their food to sustain their metabolism, including their muscular activity. Most animals derive most of their energy from aerobic respiration, namely combining the carbohy ...
, energy in food that is available *
Primary energy Primary energy (PE) is an energy form found in nature that has not been subjected to any human engineered conversion process. It is energy contained in raw fuels, and other forms of energy, including waste, received as input to a system. Prim ...
, energy contained in raw fuels and any other forms of energy received by a system as input to the system. *
Radiant energy Radiant may refer to: Computers, software, and video games * Radiant (software), a content management system * GtkRadiant, a level editor created by id Software for their games * Radiant AI, a technology developed by Bethesda Softworks for ''Th ...
, energy that is transported by waves *
Rotational energy Rotational energy or angular kinetic energy is kinetic energy due to the rotation of an object and is part of its total kinetic energy. Looking at rotational energy separately around an object's axis of rotation, the following dependence on the ob ...
, part of an object's total kinetic energy due to its rotation *
Solar radiation Solar irradiance is the power per unit area ( surface power density) received from the Sun in the form of electromagnetic radiation in the wavelength range of the measuring instrument. Solar irradiance is measured in watts per square metre ...
, radiant energy emitted by the sun, particularly electromagnetic energy *
Tidal power Tidal power or tidal energy is harnessed by converting energy from tides into useful forms of power, mainly electricity using various methods. Although not yet widely used, tidal energy has the potential for future electricity generation. ...
, also called tidal energy, is a form of hydropower that converts the energy of tides into useful forms of power - mainly electricity,
dynamic tidal power Dynamic tidal power or DTP is an untried but promising technology for tidal power generation. It would involve creating a long dam-like structure perpendicular to the coast, with the option for a coast-parallel barrier at the far end, forming a ...
,
tidal lagoon Tidal power or tidal energy is harnessed by converting energy from tides into useful forms of power, mainly electricity using various methods. Although not yet widely used, tidal energy has the potential for future electricity generation. T ...
s,
tidal barrage A tidal barrage is a dam-like structure used to capture the energy from masses of water moving in and out of a bay or river due to tidal forces. Instead of damming water on one side like a conventional dam, a tidal barrage allows water to flow ...
s *
Wave power Wave power is the capture of energy of wind waves to do useful work – for example, electricity generation, water desalination, or pumping water. A machine that exploits wave power is a wave energy converter (WEC). Waves are generated by win ...
is the transport of
energy 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 ...
by ocean surface waves, and the capture of that energy to do useful work — for example,
electricity generation Electricity generation is the process of generating electric power from sources of primary energy. For utilities in the electric power industry, it is the stage prior to its delivery ( transmission, distribution, etc.) to end users or its s ...
,
water desalination Desalination is a process that takes away mineral components from saline water. More generally, desalination refers to the removal of salts and minerals from a target substance, as in soil desalination, which is an issue for agriculture. Salt ...
, or the pumping of water (into
reservoirs A reservoir (; from French ''réservoir'' ) is an enlarged lake behind a dam. Such a dam may be either artificial, built to store fresh water or it may be a natural formation. Reservoirs can be created in a number of ways, including control ...
). Machinery able to exploit wave power is generally known as a wave energy converter (WEC). *
Wind energy Wind power or wind energy is mostly the use of wind turbines to generate electricity. Wind power is a popular, sustainable, renewable energy source that has a much smaller impact on the environment than burning fossil fuels. Historically, w ...
is the kinetic energy of air in motion;
Wind power Wind power or wind energy is mostly the use of wind turbines to generate electricity. Wind power is a popular, sustainable, renewable energy source that has a much smaller impact on the environment than burning fossil fuels. Historically ...
is the conversion of wind energy into a useful form of energy, such as using wind turbines to make electricity, windmills for mechanical power, windpumps for water pumping or drainage, or sails to propel ships


Allegorical and esoteric

*
Energy (esotericism) Proponents and practitioners of various esoteric forms of spirituality and alternative medicine refer to a variety of claimed experiences and phenomena as being due to "energy" or "force" that defy measurement and thus are distinguished from t ...
, invoked by spiritualists for alternative modes of healing the human body as well as a spirit that permeates all of reality. *
Orgone Orgone () is a pseudoscientific concept variously described as an esoteric energy or hypothetical universal life force. Originally proposed in the 1930s by Wilhelm Reich, and developed by Reich's student Charles Kelley after Reich's death in ...
,
Wilhelm Reich Wilhelm Reich ( , ; 24 March 1897 – 3 November 1957) was an Austrian doctor of medicine and a psychoanalyst, along with being a member of the second generation of analysts after Sigmund Freud. The author of several influential books, most ...
discovered this energy and tried to use it to cure various physical ailments and control the weather. *
Bioenergetic analysis Body psychotherapy, also called body-oriented psychotherapy, is an approach to psychotherapy which applies basic principles of somatic psychology. It originated in the work of Pierre Janet, Sigmund Freud and particularly Wilhelm Reich who develo ...
, body-oriented Reichian psychotherapy * Qi, a concept from
Oriental medicine Traditional Asian medicine is a collective term for several types of traditional medicine practiced in Asia. These include the medical traditions of: * East Asia ** China *** Tibet ** Japan (Kampo) ** Korea ** Mongolia * Southeast Asia ** Cambodi ...
that is sometimes translated as "energy" in the West. *
Vitalism Vitalism is a belief that starts from the premise that "living organisms are fundamentally different from non-living entities because they contain some non-physical element or are governed by different principles than are inanimate things." Wher ...
, often referred to as "energy" *
Cold fusion Cold fusion is a hypothesized type of nuclear reaction that would occur at, or near, room temperature. It would contrast starkly with the "hot" fusion that is known to take place naturally within stars and artificially in hydrogen bombs and p ...
, nuclear fusion at conditions close to room temperature. *
Bubble fusion Bubble fusion is the non-technical name for a nuclear fusion reaction hypothesized to occur inside extraordinarily large collapsing gas bubbles created in a liquid during acoustic cavitation. The more technical name is sonofusion. The term was c ...
, also known as Sonofusion, energy from acoustic collapse of bubbles. *
Water-fuelled car A water-fuelled car is an automobile that hypothetically derives its energy directly from water. Water-fuelled cars have been the subject of numerous international patents, newspaper and popular science magazine articles, local television news ...
, powering a car using water as fuel.


Politics


Energy issues

* 2000 Watt society *
Environmental concerns with electricity generation Electric power systems consist of generation plants of different energy sources, transmission networks, and distribution lines. Each of these components can have environmental impacts at multiple stages of their development and use including in ...
* Fuel poverty * Greasestock, American showcase of vehicles and technologies powered by alternative energy *
Low-carbon economy A low-carbon economy (LCE) or decarbonised economy is an economy based on energy sources that produce low levels of greenhouse gas (GHG) emissions. GHG emissions due to human activity are the dominant cause of observed climate change since the ...
* Decarbonisation plans that get to zero CO2 emissions *
Peak Oil Peak oil is the hypothetical point in time when the maximum rate of global oil production is reached, after which it is argued that production will begin an irreversible decline. It is related to the distinct concept of oil depletion; whil ...
*
Soft energy path In 1976, energy policy analyst Amory Lovins coined the term soft energy path to describe an alternative future where energy efficiency and appropriate renewable energy sources steadily replace a centralized energy system based on fossil and nucle ...
– an energy use and development strategy delineated and promoted by some energy experts and activists * Strategic Petroleum Reserve (disambiguation)


Energy policies and use – national and international


International

*
Energy policy Energy policy is the manner in which a given entity (often governmental) has decided to address issues of energy development including energy conversion, distribution and use as well as reduction of greenhouse gas emissions in order to contr ...
– an introductory article *
Energy and Environmental Security Initiative Established in 2003, the Energy and Environmental Security Initiative (EESI) is an interdisciplinary Research & Policy Institute located at the University of Colorado Law School. The fundamental mission of EESI is to serve as an interdisciplinary ...


Regional and national

*
Energy law Energy laws govern the use and taxation of energy, both renewable and non-renewable. These laws are the primary authorities (such as caselaw, statutes, rules, regulations and edicts) related to energy. In contrast, energy policy refers to th ...
– overview of many energy laws from various countries and states **
New York energy law New York energy law is the statutory, regulatory, and common law of the state of New York concerning the policy, conservation, taxation, and utilities involved in energy. Secondary sources have also influenced the law of energy in the Empire S ...
* ''
Energy Tax Act The Energy Tax Act (, , enacted November 9, 1978) is a law passed by the U.S. Congress as part of the National Energy Act. The objective of this law was to shift from oil and gas supply toward energy conservation; thus, to promote fuel efficiency a ...
'' –
United States energy The energy policy of the United States is determined by federal, state, and local entities. It addresses issues of energy production, distribution, consumption, and modes of use, such as building codes, mileage standards, and commuting polic ...
-related legislation. See also : :United States federal energy legislation * United Kingdom: **
Energy policy of the United Kingdom The energy policy of the United Kingdom refers to the United Kingdom's efforts towards reducing energy intensity, reducing energy poverty, and maintaining energy supply reliability. The United Kingdom has had success in this, though energy in ...
**
Energy use and conservation in the United Kingdom Energy in the United Kingdom came mostly from fossil fuels in 2021. Total energy consumption in the United Kingdom was 142.0million tonnes of oil equivalent (1,651 TWh) in 2019. In 2014, the UK had an energy consumption ''per capita'' of 2.78t ...


Economics

Energy economics Energy economics is a broad scientific subject area which includes topics related to supply and use of energy in societies. Considering the cost of energy services and associated value gives economic meaning to the efficiency at which energ ...


Energy companies

*
Exxon Mobil ExxonMobil Corporation (commonly shortened to Exxon) is an American multinational oil and gas corporation headquartered in Irving, Texas. It is the largest direct descendant of John D. Rockefeller's Standard Oil, and was formed on November 3 ...
* Enercon GmbH – Company based in Germany that operates in the wind turbine industry. One of the biggest producers in the world. *
Saudi Aramco Saudi Aramco ( ar, أرامكو السعودية '), officially the Saudi Arabian Oil Company (formerly Arabian-American Oil Company) or simply Aramco, is a Saudi Arabian public petroleum and natural gas company based in Dhahran. , it is one of ...
*
Sasol Sasol Limited is an integrated energy and chemical company based in Sandton, South Africa. The company was formed in 1950 in Sasolburg, South Africa and built on processes that were first developed by German chemists and engineers in the early ...
* United States Enrichment Corporation – contracts with the United States Department of Energy to produce enriched uranium.


Non-profit organizations

*
Musicians United for Safe Energy Musicians United for Safe Energy, or MUSE, is an activist group founded in 1979 by Jackson Browne, Graham Nash, Bonnie Raitt, Harvey Wasserman and John Hall. The group advocates against the use of nuclear energy, forming shortly after the Th ...


Industry associations

*
OPEC The Organization of the Petroleum Exporting Countries (OPEC, ) is a cartel of countries. Founded on 14 September 1960 in Baghdad by the first five members (Iran, Iraq, Kuwait, Saudi Arabia, and Venezuela), it has, since 1965, been headqua ...
– Organization of Petroleum-exporting Countries * IEA – International Energy Agency * CAPP – Canadian Association of Petroleum Producers * World LP Gas Association – WLPGA


Innovators

*
Alessandro Volta Alessandro Giuseppe Antonio Anastasio Volta (, ; 18 February 1745 – 5 March 1827) was an Italian physicist, chemist and lay Catholic who was a pioneer of electricity and power who is credited as the inventor of the electric battery and th ...
*
Charles Kettering Charles Franklin Kettering (August 29, 1876 – November 25, 1958) sometimes known as Charles Fredrick Kettering was an American inventor, engineer, businessman, and the holder of 186 patents. For the list of patents issued to Kettering, see, Le ...
* Farrington Daniels
solar energy Solar energy is radiant light and heat from the Sun that is harnessed using a range of technologies such as solar power to generate electricity, solar thermal energy (including solar water heating), and solar architecture. It is an essen ...
* Georges Leclanché
battery Battery most often refers to: * Electric battery, a device that provides electrical power * Battery (crime), a crime involving unlawful physical contact Battery may also refer to: Energy source *Automotive battery, a device to provide power t ...
*
John Frederic Daniell John Frederic Daniell FRS (12 March 1790 – 13 March 1845) was an English chemist and physicist. Biography Daniell was born in London. In 1831 he became the first professor of chemistry at the newly founded King's College London; and in 18 ...
Daniell cell The Daniell cell is a type of electrochemical cell invented in 1836 by John Frederic Daniell, a British chemist and meteorologist, and consists of a copper pot filled with a copper (II) sulfate solution, in which is immersed an unglazed earthenw ...
*
Rudolf Diesel Rudolf Christian Karl Diesel (, ; 18 March 1858 – 29 September 1913) was a German inventor and mechanical engineer who is famous for having invented the diesel engine, which burns diesel fuel; both are named after him. Early life and educat ...
– compression ignition
internal combustion engine An internal combustion engine (ICE or IC engine) is a heat engine in which the combustion of a fuel occurs with an oxidizer (usually air) in a combustion chamber that is an integral part of the working fluid flow circuit. In an internal co ...
*
Georges Imbert Georges Christian Peter Imbert (26 March 1884 – 6 February 1950) was a French chemical engineer and inventor. He became famous for the invention of the wood gas generator.''The Biofuels Handbook.'' Author: James G Speight. Royal Society of ...
wood gas Wood gas is a fuel gas that can be used for furnaces, stoves, and vehicles. During the production process, biomass or related carbon-containing materials are gasified within the oxygen-limited environment of a wood gas generator to produce a c ...
*
Leonardo da Vinci Leonardo di ser Piero da Vinci (15 April 14522 May 1519) was an Italian polymath of the High Renaissance who was active as a painter, draughtsman, engineer, scientist, theorist, sculptor, and architect. While his fame initially rested on ...
*
Moritz von Jacobi Moritz Hermann or Boris Semyonovich (von) Jacobi (russian: Борис Семёнович Якоби; 21 September 1801, Potsdam – 10 March 1874, Saint Petersburg) was a Prussian and Russian Imperial engineer and physicist of Jewish descent. Ja ...
*
Nicolaus Otto Nicolaus August Otto (10 June 1832, Holzhausen an der Haide, Nassau – 26 January 1891, Cologne) was a German engineer who successfully developed the compressed charge internal combustion engine which ran on petroleum gas and led to the mo ...
– internal combustion engine *
Robert Stirling Robert Stirling (25 October 1790 – 6 June 1878) was a Scottish clergyman and engineer. He invented the Stirling engine and was inducted into the Scottish Engineering Hall of Fame in 2014. Early life Robert Stirling was born at Fatal Fiel ...
Stirling engine A Stirling engine is a heat engine that is operated by the cyclic compression and expansion of air or other gas (the ''working fluid'') between different temperatures, resulting in a net conversion of heat energy to mechanical work. More specif ...
(external combustion) *
Nikola Tesla Nikola Tesla ( ; ,"Tesla"
''Random House Webster's Unabridged Dictionary''.
; 1856 – 7 January 1943 ...
*
James Watt James Watt (; 30 January 1736 (19 January 1736 OS) – 25 August 1819) was a Scottish inventor, mechanical engineer, and chemist who improved on Thomas Newcomen's 1712 Newcomen steam engine with his Watt steam engine in 1776, which was ...
steam engine A steam engine is a heat engine that performs mechanical work using steam as its working fluid. The steam engine uses the force produced by steam pressure to push a piston back and forth inside a cylinder. This pushing force can be ...
with separate condensor


Lists

*
List of books about energy issues This is a list of books about the energy industry: See also * Benjamin K. Sovacool's bibliography *'' Energy Matters'' * List of books about coal mining *List of books about nuclear issues * List of books about renewable energy * List of books ...
*
List of energy abbreviations This is a list of acronyms found in the context of energy issues. A *AAQS— Ambient Air Quality Standards (environment) (US) *AAU— Assigned amount units (measurement) *ABT— Availability based tariff (electricity) *ABF—Aquatic Base Flow ...
*
List of energy storage projects This is a list of energy storage power plants worldwide, other than pumped hydro storage. Many individual energy storage plants augment electrical grids by capturing excess electrical energy during periods of low demand and storing it in o ...
*
List of large wind farms This is a list of the largest onshore wind farms that are currently operational, rated by generating capacity. Also listed are onshore wind farms with notability other than size, and largest proposed projects. Largest operational onshore wind ...
* List of notable renewable energy organizations * List of photovoltaics companies *
List of renewable energy topics by country This is a list of renewable energy topics by country and territory. These links can be used to compare developments in renewable energy in different countries and territories and to help and encourage new writers to participate in writing about ...
*
List of solar thermal power stations This is a list of the largest facilities generating electricity through the use of solar thermal power, specifically concentrated solar power. Operational Under construction Announced Cancelled Decommissioned * Eurelios ...
* Index of wave articles *
List of wind turbine manufacturers This is a list of notable wind turbine manufacturers and businesses that manufacture major wind turbine components. Small wind turbine manufacturers * Bornay (Spain) * Enessere (Italy) * Hi-VAWT (Taiwan) * quietrevolution (United Kingdo ...


See also

* Energy (disambiguation) *
List of environment topics The natural environment, commonly referred to simply as the environment, includes all living and non-living things occurring naturally on Earth. The natural environment includes complete ecological units that function as natural systems without m ...


References


External links

{{Outline footer
Energy 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 ...
Energy 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 ...
*