ⓘ 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, electr ...

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 al ...

Earth's energy budget

Earths energy budget accounts for the balance between the energy that Earth receives from the Sun, and the energy the Earth radiates back into outer space after having been distributed throughout the five components of Earths climate system and having thus powered Earth’s so-called heat engine. This system is made up of Earths water, ice, atmosphere, rocky crust, and all living things. Quantifying changes in these amounts is required to accurately model the Earths climate. Received radiation is unevenly distributed over the planet, because the Sun heats equatorial regions more than polar r ...


Emergy is the amount of energy that was consumed in direct and indirect transformations to make a product or service. Emergy is a measure of quality differences between different forms of energy. Emergy is an expression of all the energy used in the work processes that generate a product or service in units of one type of energy. Emergy is measured in units of emjoule s, a unit referring to the available energy consumed in transformations. Emergy accounts for different forms of energy and resources Each form is generated by transformation processes in nature and each has a different abilit ...

Energy accidents

Energy resources bring with them great social and economic promise, providing financial growth for communities and energy services for local economies. However, the infrastructure which delivers energy services can break down in an energy accident, sometimes causing much damage, and energy fatalities can occur, and with many systems often deaths will happen even when the systems are working as intended. Historically, coal mining has been the most dangerous energy activity and the list of historical coal mining disasters is a long one. Underground mining hazards include suffocation, gas poi ...

Energy broker

Energy brokers assist clients in procuring electric or natural gas from energy wholesalers/suppliers. Since electricity and natural gas are commodities, prices change daily with the market. It is challenging for most businesses without energy managers to obtain price comparisons from a variety of suppliers since prices must be compared on exactly the same day. In addition, the terms of the particular contract offered by the supplier influences the price that is quoted. An energy broker can provide a valuable service if they work with a large number of suppliers and can actually compile the ...

Energy customer switching

Energy customer switching is a concept stemming from the global energy markets. The concept refers to the action of one energy customer switching energy supplier, a switch is essentially seen as the free movement of a customer. In addition to that a switch can include: A re-switch: When a customer switches for the second or subsequent time. A switch-back: When a customer switches back to his/her former or previous supplier. If a customer moves, there is often a switch, however this will only be counted if the customer is not dealing with the incumbent in the new area of residence. The abov ...

Energy density

Energy density is the amount of energy stored in a given system or region of space per unit volume. Colloquially it may also be used for energy per unit mass, though the accurate term for this is specific energy. Often only the useful or extractable energy is measured, which is to say that inaccessible energy is ignored. In cosmological and other general relativistic contexts, however, the energy densities considered are those that correspond to the elements of the stress–energy tensor and therefore do include mass energy as well as energy densities associated with the pressures described ...

Energy flow (ecology)

In ecology, energy flow, also called the calorific flow, refers to the flow of energy through a food chain, and is the focus of study in ecological energetics. In an ecosystem, ecologists seek to quantify the relative importance of different component species and feeding relationships. A general energy flow scenario follows: Secondary consumers, carnivores, then consume the primary consumers, although omnivores also consume primary producers. Energy that had been used by the primary consumers for growth and storage is thus absorbed into the secondary consumers through the process of digest ...

Energy informatics

Energy informatics is a research field covering the use of information and communication technology to address energy utilization and management challenges. Methods used for "smart" implementations often combine IoT sensors with artificial intelligence and machine learning. Energy Informatics is founded on flow networks that are the major suppliers and consumers of energy. Their efficiency can be improved by collecting and analyzing information.

Energy management

Energy management includes planning and operation of energy production and energy consumption units. Objectives are resource conservation, climate protection and cost savings, while the users have permanent access to the energy they need. It is connected closely to environmental management, production management, logistics and other established business functions. The VDI-Guideline 4602 released a definition which includes the economic dimension:" Energy management is the proactive, organized and systematic coordination of procurement, conversion, distribution and use of energy to meet the ...

Energy management software

Energy Management Software is a general term and category referring to a variety of energy-related software applications which may provide utility bill tracking, real-time metering, building HVAC and lighting control systems, building simulation and modeling, carbon and sustainability reporting, IT equipment management, demand response, and/or energy audits. Managing energy can require a system of systems approach. Energy management software often provides tools for reducing energy costs and consumption for buildings or communities. EMS collects energy data and uses it for three main purpo ...

Energy monitoring and targeting

Energy monitoring and targeting is an energy efficiency technique based on the standard management axiom stating that" you cannot manage what you cannot measure”. M&T techniques provide energy managers with feedback on operating practices, results of energy management projects, and guidance on the level of energy use that is expected in a certain period. Importantly, they also give early warning of unexpected excess consumption caused by equipment malfunctions, operator error, unwanted user behaviours, lack of effective maintenance and the like. The foundation of M&T lies in determ ...

Energy operator

In quantum mechanics, energy is defined in terms of the energy operator, acting on the wave function of the system as a consequence of time translation symmetry.

Energy rate density

Energy rate density is the amount of free energy per unit time per unit mass. It is terminologically equivalent to power density when measured in SI units of W/kg. Regardless of the units used, energy rate density describes the flow of energy through any system of given mass, and has been proposed as a measure of system complexity. The more complex the system, the more energy flows per second through each gram. Energy rate density is actually a general term that is equivalent to more specialized terms used by many different disciplinary scientists. For example, in astronomy it is called th ...

Energy system

An energy system is a system primarily designed to supply energy-services to end-users. Taking a structural viewpoint, the IPCC Fifth Assessment Report defines an energy system as "all components related to the production, conversion, delivery, and use of energy". The field of energy economics includes energy markets and treats an energy system as the technical and economic systems that satisfy consumer demand for energy in the forms of heat, fuels, and electricity. The first two definitions allow for demand-side measures, including daylighting, retrofitted building insulation, and passive ...


Exertion is the physical or perceived use of energy. Exertion traditionally connotes a strenuous or costly effort, resulting in generation of force, initiation of motion, or in the performance of work. It often relates to muscular activity and can be quantified, empirically and by measurable metabolic response.

Fowkes hypothesis

The Fowkes hypothesis is a first order approximation for surface energy. It states the surface energy is the sum of each components forces: γ=γ d +γ p +γ i +. where γ d is the dispersion component, γ p is the polar, γ i is the dipole and so on. The Fowkes hypothesis goes further making the approximation that the interface between an apolar liquid and apolar solid where there are only dispersive interactions acting across the interface can be estimated using the geometric mean of the contributions from each surface i.e. γ SL =γ S +γ L -2γ S p x γ L p 1/2

Fusion energy gain factor

The fusion energy gain factor, usually expressed with the symbol Q, is the ratio of fusion power produced in a nuclear fusion reactor to the power required to maintain the plasma in steady state. The condition of Q = 1, when the power being released by the fusion reactions is equal to the required heating power, is referred to as breakeven, or in some sources, scientific breakeven. The energy given off by the fusion reactions may be captured within the fuel, leading to self-heating. Most fusion reactions release at least some of their energy in a form that cannot be captured within the pla ...

Greisen–Zatsepin–Kuzmin limit

The Greisen–Zatsepin–Kuzmin limit is a theoretical upper limit on the energy of cosmic ray protons traveling from other galaxies through the intergalactic medium to our galaxy. The limit is 5 × 10 19 eV, or about 8 joules. The limit is set by slowing interactions of the protons with the microwave background radiation over long distances. The limit is at the same order of magnitude as the upper limit for energy at which cosmic rays have experimentally been detected. For example, one extreme-energy cosmic ray, the Oh-My-God Particle, which has been found to possess a record-breaking 3.12 × 1 ...

Intelligent Energy

Intelligent Energy is a fuel cell engineering company focused on the development and commercialisation of its PEM fuel cell technologies for a range of markets including automotive, stationary power and UAVs. It is headquartered in the UK, with offices and representation in the US, Japan, Korea, and China.


Margham is an oil and gas field in Dubai, United Arab Emirates and the largest onshore gas field in the emirate. The field is managed by Dusup - the Dubai Supply Authority. Condensate production ran at some 25.000 barrels per day in 2010. Margham also has an oil production capability. Production at Margham commenced in 1984, with three major gas-bearing formations located up to 10.000 feet below sea level. The field is connected by pipeline to Jebel Ali, where the gas condensate is loaded onto tankers for export. Dry gas is now also sent by pipeline to supply the Dubai grid, with consumpti ...

Maximum power principle

The maximum power principle or Lotkas principle has been proposed as the fourth principle of energetics in open system thermodynamics, where an example of an open system is a biological cell. According to Howard T. Odum, "The maximum power principle can be stated: During self-organization, system designs develop and prevail that maximize power intake, energy transformation, and those uses that reinforce production and efficiency."

National Hydrogen and Fuel Cell Day

National Hydrogen and Fuel Cell Day was created by the Fuel Cell and Hydrogen Energy Association to help raise awareness of fuel cell and hydrogen technologies and to celebrate how far the industry has come as well as the vast potential the technologies have today and in future. October 8th 10.08 was chosen in reference to the atomic weight of hydrogen 1.008. National Hydrogen and Fuel Cell Day was officially launched on October 8, 2015.

NET Power Demonstration Facility

The NET Power Demonstration Facility, located in La Porte, Tx, is an oxy-combustion, zero-emissions 50 MWth natural gas power plant operated by NET Power and owned by Exelon, McDermott, Oxy Low Carbon Ventures, and 8 Rivers Capital. The plant is a first of its kind Allam Power Cycle demonstration facility which achieved first-fire in May of 2018. The Allam Power Cycle has the potential to deliver lower cost power while eliminating atmospheric emissions. The plant was featured in The Global CCS Institutes 2018 Status of CCS report. With the success of its demonstration plant, NET Power is l ...

Open energy system databases

Open energy system database projects employ open data methods to collect, clean, and republish energy-related datasets for open use. The resulting information is then available, given a suitable open license, for statistical analysis and for building numerical energy system models, including open energy system models. Permissive licenses like Creative Commons CC0 and CC BY are preferred, but some projects will house data made public under market transparency regulations and carrying unqualified copyright. The databases themselves may furnish information on national power plant fleets, rene ...

Orders of magnitude (energy)

The joule is named after James Prescott Joule. As with every SI unit named for a person, its symbol starts with an upper case letter J, but when written in full it follows the rules for capitalisation of a common noun; i.e., joule becomes capitalised at the beginning of a sentence and in titles, but is otherwise in lower case.

Phakalane power station

Phakalane Power Station is a photovoltaic pilot power plant located in Phakalane, Botswana. The power station was funded through a Japanese grant which was part of Prime Minister Hatoyamas initiative strategy called Cool Earth Partnership aimed at supporting developing countries in their efforts to combat global warming. The Cool Earth Partnership is part of the initiatives which saw Hatoyama win the Sustainable Development Leadership Award in 2010.

Primary energy

Primary energy 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 received as input to a system. Primary energy can be non-renewable or renewable. Where primary energy is used to describe fossil fuels, the embodied energy of the fuel is available as thermal energy and around 70% is typically lost in conversion to electrical or mechanical energy. There is a similar 60-80% conversion loss when solar and wind energy is converted to electricity, but todays UN conventions on ene ...

Statistical study of energy data

Energy statistics refers to collecting, compiling, analyzing and disseminating data on commodities such as coal, crude oil, natural gas, electricity, or renewable energy sources, when they are used for the energy they contain. Energy is the capability of some substances, resulting from their physico-chemical properties, to do work or produce heat. Some energy commodities, called fuels, release their energy content as heat when they burn. This heat could be used to run an internal or external combustion engine. The need to have statistics on energy commodities became obvious during the 1973 ...

United States Energy Association

The United States Energy Association is the U.S. Member Committee of the World Energy Council. Headquartered in Washington, D.C., USEA is an association of public and private energy-related organizations, corporations, and government agencies. The association hosts annual events such as the Carbon Sequestration Leadership Forum, Energy Supply Forum, and State of the Energy Industry Forum.

Water-energy nexus

There is no formal definition for the water-energy nexus – the concept refers to the relationship between the water used for energy production, including both electricity and sources of fuel such as oil and natural gas, and the energy consumed to extract, purify, deliver, heat/cool, treat and dispose of water sometimes referred to as the energy intensity. The relationship is not truly a closed loop as the water used for energy production need not be the same water that is processed using that energy, but all forms of energy production require some input of water making the relationship ine ...

Free and no ads
no need to download or install

Pino - logical board game which is based on tactics and strategy. In general this is a remix of chess, checkers and corners. The game develops imagination, concentration, teaches how to solve tasks, plan their own actions and of course to think logically. It does not matter how much pieces you have, the main thing is how they are placement!

online intellectual game →