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Energy density is the amount of energy
Energy

In physics, energy is a scalar physical quantity that describes the amount of Work_ that can be performed by a force. Energy is an attribute of objects and systems that is subject to a conservation law....
 stored in a given system or region of space per unit volume
Volume

The volume of any solid, liquid, plasma, vacuum or theoretical object is how much three-dimensional space it occupies, often quantified numerically....
, or per unit mass
Mass

In physical science, mass refers to the degree of acceleration a body acquires when subject to a force: bodies with greater mass are accelerated less by the same force....
, depending on the context, although the latter is more formally specific energy
Specific energy

Specific energy is defined as the energy per unit mass: J/kg or, in basic SI units: m2/s2. It is an intensive property. Contrast this with energy, which is an extensive property....
 . In some cases it is obvious from context which quantity is most useful: for example, in rocketry, energy per unit mass is the most important parameter, but when studying pressurized gas or magnetohydrodynamics
Magnetohydrodynamics

Magnetohydrodynamics is the academic discipline which studies the dynamics of electrical conduction fluids. Examples of such fluids include Plasma , liquid metals, and Brine....
 the energy per unit volume is more appropriate.






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Energy density is the amount of energy
Energy

In physics, energy is a scalar physical quantity that describes the amount of Work_ that can be performed by a force. Energy is an attribute of objects and systems that is subject to a conservation law....
 stored in a given system or region of space per unit volume
Volume

The volume of any solid, liquid, plasma, vacuum or theoretical object is how much three-dimensional space it occupies, often quantified numerically....
, or per unit mass
Mass

In physical science, mass refers to the degree of acceleration a body acquires when subject to a force: bodies with greater mass are accelerated less by the same force....
, depending on the context, although the latter is more formally specific energy
Specific energy

Specific energy is defined as the energy per unit mass: J/kg or, in basic SI units: m2/s2. It is an intensive property. Contrast this with energy, which is an extensive property....
 . In some cases it is obvious from context which quantity is most useful: for example, in rocketry, energy per unit mass is the most important parameter, but when studying pressurized gas or magnetohydrodynamics
Magnetohydrodynamics

Magnetohydrodynamics is the academic discipline which studies the dynamics of electrical conduction fluids. Examples of such fluids include Plasma , liquid metals, and Brine....
 the energy per unit volume is more appropriate. In a few applications (comparing, for example, the effectiveness of hydrogen
Hydrogen

Hydrogen is the chemical element with atomic number 1. It is represented by the chemical symbol H. At standard temperature and pressure, hydrogen is a colorless, odorless, nonmetallic, tasteless, highly combustion and explosive Diatomic molecule gas with the molecular formula H2....
 fuel to gasoline
Gasoline

File:GasCan.jpgGasoline or petrol is a petroleum-derived liquid mixture, primarily used as fuel in internal combustion engines.It consists mostly of aliphatic hydrocarbons, enhanced with iso-octane or the aromatic hydrocarbons toluene and benzene to increase its octane rating....
) both figures are appropriate and should be called out explicitly. (Hydrogen has a higher energy density per unit mass than does gasoline, but a much lower energy density per unit volume)

Energy per unit volume has the same physical units as pressure
Pressure

Pressure is the force per unit area applied to an object in a direction surface normal to the surface. Gauge pressure is the pressure relative to the local atmospheric or ambient pressure....
, and in many circumstances is an exact synonym
Synonym

Synonyms are different words with identical or very similar meanings. Words that are synonyms are said to be synonymous, and the state of being a synonym is called synonymy....
: for example, the energy density of the magnetic field may be expressed as (and behaves as) a physical pressure, and the energy required to compress a gas may be determined by multiplying the pressure of the compressed gas times its change in volume.

Energy density in energy storage and in fuel


In energy storage
Energy storage

Energy storage mediums are matter that store of some form of energy that can be drawn upon at a later time to perform some useful operation. A device that stores energy is sometimes called an Accumulator ....
 application the energy density relates the mass
Mass

In physical science, mass refers to the degree of acceleration a body acquires when subject to a force: bodies with greater mass are accelerated less by the same force....
 of an energy store to its stored energy. The higher the energy density, the more energy may be stored or transported for the same amount of mass. In the context of fuel
Fuel

Fuel is any material that is burned or altered in order to obtain energy and to heat or to move an object. Fuel releases its energy either through a chemical reaction means, such as combustion, or nuclear means, such as nuclear fission or nuclear fusion....
 selection, that energy density of a fuel is also called the specific energy
Specific energy

Specific energy is defined as the energy per unit mass: J/kg or, in basic SI units: m2/s2. It is an intensive property. Contrast this with energy, which is an extensive property....
 of that fuel, though in general an engine
Engine

An engine is a mechanical device that produces some form of output from a given input.An engine whose purpose is to produce kinetic energy output from a fuel is called a Wiktionary:prime mover; alternatively, a motor is a device which produces kinetic energy from a preprocessed "fuel" ....
 using that fuel will yield less energy due to inefficiencies
Inefficiency

The Term inefficiency has several meanings depending on the context in which its used:*Algorithmic efficiency - refers to less than optimum computer programs that might exhibit one of more of the symptoms of:-...
 and thermodynamic
Thermodynamics

In physics, thermodynamics is the study of the conversion of heat energy into different forms of energy ; different energy conversions into heat energy; and its relation to macroscopic variables such as temperature, pressure, and volume....
 considerations—hence the specific fuel consumption
Specific fuel consumption

Specific fuel consumption, often shortened to SFC, or TSFC is an engineering term that is used to describe the fuel efficiency of an engine design with respect to thrust output....
 of an engine will be greater than the reciprocal
Reciprocal

Reciprocal may refer to:*Multiplicative inverse, in mathematics, the number 1/x, which multiplied by x'' gives the product 1, also known as a reciprocal...
 of the specific energy of the fuel.

The highest density sources of energy are fusion
Nuclear fusion

In nuclear physics and nuclear chemistry, nuclear fusion is the process by which multiple like-charged atomic nuclei join together to form a heavier nucleus....
 and fission
Fission

Fission is a splitting of something into two parts.Fission may refer to:*In physics, nuclear fission is a process where a large atomic nucleus is split into two smaller particles....
. Fusion includes energy from the sun which will be available for billions of years (in the form of sunlight
Sunlight

Sunlight, in the broad sense, is the total spectroscopy of the electromagnetic radiation given off by the Sun. On Earth, sunlight is Filter ed through the Earth's atmosphere, and the solar radiation is obvious as daylight when the Sun is above the horizon....
) but humans have not learned to make our own sustained fusion power sources. Fission of U-235 in nuclear power plants will be available for billions of years because of the vast supply of the element on earth . Coal
Coal

Coal is a readily combustion black or brownish-black sedimentary rock. The harder forms, such as anthracite, can be regarded as metamorphic rock because of later exposure to elevated temperature and pressure....
 and petroleum
Petroleum

Petroleum or crude oil is a naturally occurring, flammable liquid found in rock formations in the Earth consisting of a complex mixture of hydrocarbons of various molecular weights, plus other organic compounds....
 are the current primary energy sources in the U.S. but have a much lower energy density. Burning local biomass
Biomass

Biomass, as a renewable energy source, refers to living and recently dead biological material that can be used as fuel or for industrial production....
 fuels supplies household energy needs (cooking fires, oil lamp
Oil lamp

An oil lamp is a simple vessel used to produce light continuously for a period of time from a fuel source. The use of oil lamps extends from prehistory to the present day....
s, etc.) worldwide.

Energy density (how much energy you can carry) does not tell you about energy conversion efficiency
Energy conversion efficiency

File:Efficiency diagram by Zureks.svgEnergy conversion efficiency is the ratio between the useful output of an energy conversion machine and the input, in energy terms....
 (net output per input) or embodied energy
Embodied energy

Embodied energy refers to the quantity of energy required to manufacture, and supply to the point of use, a product, material or service. .Traditionally considered, embodied energy is an accounting methodology which aims to find the sum total of the energy necessary - from the raw material extraction, to transport, manufacturing, assembly,...
 (what the energy output costs to provide, as harvesting
Energy industry

The energy industry is a generic term for all of the industry involved the production and sale of energy, including fuel extraction, manufacturing, oil refinery and distribution....
, refining
Refinery

A refinery is composed of a group of chemical engineering Unit processing and unit operations used for refining certain materials or converting materials into products of value....
, distributing, and dealing with pollution
Pollution

Pollution is the introduction of contaminants into an environment that causes instability, disorder, harm or discomfort to the ecosystem i.e. physical systems or living organisms ....
 all use energy). Like any process occurring on a large scale, intensive energy use creates environmental impacts: for example, global warming
Global warming

Global warming is the increase in the Instrumental temperature record of the Earth's near-surface air and the oceans since the mid-twentieth century and its projected continuation....
, nuclear waste storage, and deforestation
Deforestation

Deforestation is the logging or burning of trees in forested areas. There are several reasons for doing so: trees or derived charcoal can be sold as a commodity and are used by humans while cleared land is used as pasture, plantations of commodities and human settlement....
 are a few of the consequences of supplying our growing energy demands from fossil fuels, nuclear fission, or biomass.

By dividing by 3.6 the figures for megajoules per kilogram can be converted to kilowatt-hours per kilogram. Unfortunately, the useful energy available by extraction from an energy store is always less than the energy put into the energy store, as explained by the laws of thermodynamics
Laws of thermodynamics

The laws of thermodynamics, in principle, describe the specifics for the transport of heat and Work in thermodynamic processes. Since their inception, however, these Physical laws have become some of the most important in all of physics and other branches of science connected to thermodynamics....
. No single energy storage method boasts the best in specific power
Specific power

In engineering, the term specific power can refer to power either per unit of mass, volume or area, although power per unit of volume is more formally known as power density, and power per unit area as surface power density....
, specific energy
Specific energy

Specific energy is defined as the energy per unit mass: J/kg or, in basic SI units: m2/s2. It is an intensive property. Contrast this with energy, which is an extensive property....
, and energy density. Peukert's Law
Peukert's law

Peukert's Law, presented by the German scientist W. Peukert in 1897, expresses the capacity of a lead-acid battery in terms of the rate at which it is discharged....
 describes how the amount of energy we get out depends how quickly we pull it out.

Gravimetric and volumetric energy density of some fuels and storage technologies (modified from the Gasoline
Gasoline

File:GasCan.jpgGasoline or petrol is a petroleum-derived liquid mixture, primarily used as fuel in internal combustion engines.It consists mostly of aliphatic hydrocarbons, enhanced with iso-octane or the aromatic hydrocarbons toluene and benzene to increase its octane rating....
 article):
Note: Some values may not be precise because of isomers or other irregularities. See Heating value for a comprehensive table of specific energies of important fuels.


True energy densities


This table gives the energy density of a complete system, including all needed oxidisers.

ANFO
ANFO

ANFO is a widely used explosive mixture. The oil used is most often Heating oil, or diesel fuel, but sometimes kerosene, coal dust, or even molasses....
>
Energy Densities Table
Storage typeEnergy density by mass (MJ/kg)Energy density by volume (MJ/L
Litér

Lit?r is a village in Veszpr?m , Hungary.External links ...
)		Peak recovery efficiency %Practical recovery efficiency %
Mass-energy equivalence
Mass-energy equivalence

In physics, mass?energy equivalence is the concept that any mass has an associated energy, and that any energy has an associated type of mass. In special relativity this relationship is expressed using the mass?energy equivalence formula...
89,876,000,000  
Nuclear fusion
Nuclear fusion

In nuclear physics and nuclear chemistry, nuclear fusion is the process by which multiple like-charged atomic nuclei join together to form a heavier nucleus....
 of hydrogen (energy from the sun
Sun

The Sun , a G V star, is the star at the center of the Solar System. The Earth and other matter orbit the Sun, which by itself accounts for about 98.6% of the Solar System's mass....
)		645,000,000  
Deuterium-Tritium fusion337,000,000  
Nuclear fission
Nuclear fission

In nuclear physics and nuclear chemistry, nuclear fission is a nuclear reaction in which the atomic nucleus of an atom splits into smaller parts, often producing free neutrons and lighter atomic nucleus, which may eventually produce photons ....
 (of 100% U-235
U-235

U235 or U-235 may be:* German submarine U-235, a German U-boat of World War II* Uranium-235, an isotope of uraniumbang bang there goes the ship...
) (Used in nuclear power plants)		88,250,0001,500,000,000  
Natural uranium
Uranium

Uranium is a silvery-gray metallic chemical element in the actinide series of the periodic table that has the chemical symbol U and atomic number 92....
 (99.3% U238, 0.7% U235) in fast breeder reactor
Fast breeder reactor

The fast breeder or fast breeder reactor is a fast neutron reactor designed to breed fuel by producing more fissile material than it consumes....
24,000,000  [https://netfiles.uiuc.edu/mragheb/www/NPRE%20402%20ME%20405%20Nuclear%20Power%20Engineering/High%20Temperature%20Gas%20Cooled%20Reactor%20HTGR.pdf 50%]
Enriched uranium
Uranium

Uranium is a silvery-gray metallic chemical element in the actinide series of the periodic table that has the chemical symbol U and atomic number 92....
 (3.5% U235) in light water reactor
Light water reactor

The light water reactor or LWR is a type of thermal reactor, a reactor that uses a neutron moderator to reduce the speed of neutrons to low velocity thermal neutrons....
3,456,000  30%
Heat engine

A heat engine is a physical or theoretical device that converts thermal energy to mechanical output. The mechanical output is called Mechanical work, and the thermal energy input is called heat....
Hf-178m2 isomer
Nuclear isomer

A nuclear isomer is a metastable state of an atomic nucleus caused by the excited state of one or more of its nucleons. A nuclear isomer occupies a higher energy state than the corresponding non-excited nucleus, called the ground state....
1,326,00017,649,060  
Natural uranium
Uranium

Uranium is a silvery-gray metallic chemical element in the actinide series of the periodic table that has the chemical symbol U and atomic number 92....
 (0.7% U235) in light water reactor
Light water reactor

The light water reactor or LWR is a type of thermal reactor, a reactor that uses a neutron moderator to reduce the speed of neutrons to low velocity thermal neutrons....
443,000  30%
Heat engine

A heat engine is a physical or theoretical device that converts thermal energy to mechanical output. The mechanical output is called Mechanical work, and the thermal energy input is called heat....
Ta-180m isomer
Nuclear isomer

A nuclear isomer is a metastable state of an atomic nucleus caused by the excited state of one or more of its nucleons. A nuclear isomer occupies a higher energy state than the corresponding non-excited nucleus, called the ground state....
41,340689,964  
Specific orbital energy
Specific orbital energy

In astrodynamics the specific orbital energy of an orbiting body traveling through space under standard assumptions in astrodynamics is the sum of its potential energy and kinetic energy per unit mass....
 of Low Earth orbit
Low Earth orbit

A Low Earth Orbit is generally defined as an orbit within the Locus extending from the Earth?s surface up to an altitude of 2,000 km. Given the rapid orbital decay of objects below approximately 200 km, the commonly accepted definition for LEO is between 160 - 2,000 km above the Earth surface....
 (approximate)		33  
Cl2O7
Dichlorine heptoxide

Dichlorine heptoxide is the chemical compound with the Chemical formula Cl2O7. This chlorine oxide is the acid anhydride of perchloric acid....
 + CH4 - computed		17.4  
Cl2O7
Dichlorine heptoxide

Dichlorine heptoxide is the chemical compound with the Chemical formula Cl2O7. This chlorine oxide is the acid anhydride of perchloric acid....
 decomposition - computed		12.2  
Nitromethane
Nitromethane

Nitromethane is an organic compound with the chemical formula CH3NO2. It is the simplest organic nitro compound. It is a slightly viscous, highly polar liquid commonly used as a solvent in a variety of industrial applications such as in extractions, as a reaction medium, and as a cleaning solvent....
11.312.9  
Octanitrocubane
Octanitrocubane

Octanitrocubane is a powerful high explosive that, like Trinitrotoluene, is shock-insensitive . The octanitrocubane molecule has the same chemical structure as cubane except that each of the eight hydrogen atoms are replaced by a nitro compound ....
 explosive - computed		8.517  
Tetranitrotetrahedrane explosive - computed8.3  
Heptanitrocubane
Heptanitrocubane

Heptanitrocubane is a new experimental Explosive based on the cubic eight-carbon cubane molecule and closely related to octanitrocubane. Seven of the eight hydrogen atoms at the corners of the cubane molecule are replaced by nitro groups, giving the final molecular formula ....
 explosive - computed		8.2  
Dinitroacetylene explosive - computed 7.9  
Sodium
Sodium

Sodium is an element which has the symbol Na , atomic number 11, atomic mass 23 amu , and a common oxidation number +1. Sodium is a soft, silvery white, highly reactive element and is a member of the alkali metals within "group 1" ....
 (reacted with chlorine)		7.0349  
Tetranitrocubane explosive - computed6.95  
Ammonal
Ammonal

Ammonal is an explosive made up of ammonium nitrate, trinitrotoluene, and aluminium powder mixed in a ratio of roughly 22:67:11.The ammonium nitrate functions as an oxidizer and aluminium as a power enhancer....
 (Al+NH4NO3
Ammonium nitrate

The chemical compound ammonium nitrate, the nitrate of ammonia with the chemical formula NitrogenHydrogen4NitrogenOxygen3, is a white powder at room temperature and standard pressure....
 oxidizer)		6.912.7  
Tetranitromethane
Tetranitromethane

Tetranitromethane or TNM is an organic chemical oxidizer with chemical formula C4. Its chemical structure consists of four nitro groups attached to one carbon atom....
 + hydrazine
Hydrazine

Hydrazine is a chemical compound with the chemical formula N2H4. It is a colourless liquid with an ammonia-like odor and is derived from the same industrial chemistry processes that manufacture ammonia....
 bipropellant - computed		6.6  
Hexanitrobenzene
Hexanitrobenzene

Hexanitrobenzene, also known as HNB, is a high-density explosive compound with chemical formula Carbon6Nitrogen6Oxygen12, obtained by oxidation the amine group of pentanitroaniline with hydrogen peroxide in sulfuric acid....
 explosive - computed		6.5  
Octogen explosive - computed6.3  
ANFO
ANFO

ANFO is a widely used explosive mixture. The oil used is most often Heating oil, or diesel fuel, but sometimes kerosene, coal dust, or even molasses....
-ANNM		6.26  
TNT
Trinitrotoluene

Trinitrotoluene , or more specifically, 2,4,6-trinitrotoluene, is a chemical compound with the formula C6H23CH3....
 []		4.6106.92  
Copper Thermite
Thermite

Thermite is a pyrotechnic composition of a metal powder and a metal oxide, which produces an aluminothermic reaction known as a thermite reaction....
  (Al + CuO
Copper(II) oxide

Copper oxide or cupric oxide is the higher oxide of copper. As a mineral, it is known as tenorite....
 as oxidizer)		4.1320.9  
Thermite
Thermite

Thermite is a pyrotechnic composition of a metal powder and a metal oxide, which produces an aluminothermic reaction known as a thermite reaction....
 (powder Al + Fe2O3
Iron(III) oxide

Iron oxide?also known as ferric oxide, Hematite, red iron oxide, synthetic maghemite, colcothar, or simply rust?is one of the several oxide Chemical compounds of iron, and has Paramagnetism properties....
 as oxidizer)		4.0018.4  
3.7  
Hydrogen peroxide
Hydrogen peroxide

Hydrogen peroxide is a very pale blue liquid which appears colorless in a dilute solution, slightly more viscous than water. It is a weak acid....
 decomposition (as monopropellant
Monopropellant

Monopropellants are propellants composed of chemicals or mixtures of chemicals which can be stored in a single container with some degree of safety....
)		2.73.8  
battery, Lithium ion nanowire
Nanowire battery

A nanowire battery is a lithium-ion battery invented by a team led by Dr. Yi Cui at Stanford University in 2007. The team's invention consists of a stainless steel anode covered in silicon nanowires, to replace the traditional graphite anode....
2.5429  DisplayLink("http://news-service.stanford.edu/news/2008/january9/nanowire-010908.html", "(*)")
battery, Lithium Thionyl Chloride (LiSOCl2) 2.5  
Water
Water

Water is a common chemical substance that is essential for the survival of all known forms of life. In typical usage, water refers only to its liquid form or States of matter, but the substance also has a solid state, ice, and a gaseous state, water vapor or steam....
 220.64 bar, 373.8°C 		1.9680.708  
Kinetic energy penetrator
Kinetic energy penetrator

A kinetic energy penetrator is a type of ammunition which, like a bullet, does not contain explosives and uses kinetic energy to penetrate the target....
 		1.930  
battery, Fluoride ion 1.72.8  
battery, Hydrogen closed cycle H fuel cell
Fuel cell

A fuel cell is an Electrochemistry conversion device. It produces electricity from fuel and an Oxidizing agent , which react in the presence of an electrolyte....
1.62  
Hydrazine
Hydrazine

Hydrazine is a chemical compound with the chemical formula N2H4. It is a colourless liquid with an ammonia-like odor and is derived from the same industrial chemistry processes that manufacture ammonia....
(toxic) decomposition (as monopropellant
Monopropellant

Monopropellants are propellants composed of chemicals or mixtures of chemicals which can be stored in a single container with some degree of safety....
)		1.61.6  
Ammonium nitrate
Ammonium nitrate

The chemical compound ammonium nitrate, the nitrate of ammonia with the chemical formula NitrogenHydrogen4NitrogenOxygen3, is a white powder at room temperature and standard pressure....
 decomposition (as monopropellant
Monopropellant

Monopropellants are propellants composed of chemicals or mixtures of chemicals which can be stored in a single container with some degree of safety....
)		1.42.5  
Capacitor
Capacitor

A capacitor or condenser is a Passive component electronic component consisting of a pair of electrical conductor separated by a dielectric....
 by EEStor
EEStor

EEStor is a company based in Cedar Park, Texas, Texas, United States that claims to have developed a revolutionary new type of capacitor for electricity storage, which EEStor calls 'Electrical Energy Storage Units' , ....
 (claimed prototype capacity) 		1.02.18  
Thermal energy storage
Thermal energy storage

Thermal energy storage can refer to a number of technologies that Energy storage in a thermal reservoir for later reuse. They can be employed to balance energy demand between day time and night time....
(Molten Salt) approximate 		1  
Molecular spring
Molecular spring

A Molecular spring is a device or part of a biological system based on molecular mechanics and is associated with molecular vibration.Any molecule can be deformed in several ways - A-A bond length, A-A-A angle, A-A-A-A torsion angle....
 approximate		1  
battery, Sodium Sulfur
Sodium-sulfur battery

A sodium-sulfur battery is a type of battery constructed from sodium and sulfur . This type of battery has a high energy density, high efficiency of charge/discharge and long cycle life, and is fabricated from inexpensive materials....
 0 1.23 85%
Liquid nitrogen
Liquid nitrogen economy

A liquid nitrogen economy is a hypothetical proposal for a future economy in which the primary form of energy storage and transport is liquid nitrogen....
0.770.62  
battery, Lithium ion
Lithium ion battery

Lithium-ion batteries are a type of rechargeable battery in which a lithium ion moves between the anode and cathode. The lithium ion moves from the anode to the cathode during discharge and in reverse, from the cathode to the anode, when charging....
0.540.9 95%
battery, Lithium Sulphur0.54  
compressed air
Compressed air energy storage

Compressed Air Energy Storage refers to the air compressorto be used later as energy source.At utility scale, it can be stored during periods of low energy demand , for use in meeting periods of higher demand ....
 at 300 bar (at 12°C), without container		0.5120.16  
Flywheel
Flywheel energy storage

Flywheel energy storage works by accelerating a rotor to a very high speed and maintaining the energy in the system as rotational energy. The energy is converted back by slowing down the flywheel....
0.5 1-0.15%/10s
5.56 × 45 mm NATO bullet 0.4 3.2  
Ice(Ice)0.3350.335  
battery, Zinc Bromine flow (ZnBr)
Zinc-bromine flow battery

The zinc-bromine flow battery is a type of hybrid flow battery. A solution of zinc bromide is stored in two tanks. When the battery is charged or discharged the solutions are pumped through a reactor and back into the tanks....
0.27  
Compressed air
Compressed air energy storage

Compressed Air Energy Storage refers to the air compressorto be used later as energy source.At utility scale, it can be stored during periods of low energy demand , for use in meeting periods of higher demand ....
 at 20 bar (at 12°C), without container		0.270.01 64%
battery, NiMH
Nickel metal hydride battery

A nickel-metal hydride cell, abbreviated NiMH, is a type of rechargeable battery similar to Nickel Hydrogen cell. The NiMH battery uses a hydrogen-absorbing alloy for the negative electrode instead of cadmium....
0.2500.493 
battery, NiCd0.14 80%
battery, Lead acid0.09  
Compressed air
Compressed air energy storage

Compressed Air Energy Storage refers to the air compressorto be used later as energy source.At utility scale, it can be stored during periods of low energy demand , for use in meeting periods of higher demand ....
 in fiber-wound bottle at 200 bar (at 24°C)		0.140.06  
battery, Vandium redox
Vanadium redox battery

The vanadium redox battery in its present form was patented by the University of New South Wales in Australia in 1986 . It is a type of rechargeable flow battery that employs vanadium redox couples in both half-cells, thereby eliminating the problem of cross contamination by diffusion of ions across the membrane....
0.09 0.1188 7070-75%
battery, Vandium Bromide redox0.18 0.252 81%
compressed air
Compressed air energy storage

Compressed Air Energy Storage refers to the air compressorto be used later as energy source.At utility scale, it can be stored during periods of low energy demand , for use in meeting periods of higher demand ....
 in steel bottle at 200 bar (at 24°C)		0.040.1  
Capacitor
Capacitor

A capacitor or condenser is a Passive component electronic component consisting of a pair of electrical conductor separated by a dielectric....
 Ultracapacitor		0.0206 0.050  
Capacitor
Capacitor

A capacitor or condenser is a Passive component electronic component consisting of a pair of electrical conductor separated by a dielectric....
 Supercapacitor
Supercapacitor

Electric double-layer capacitors, also known as supercapacitors, electrical double layer capacitors or ultracapacitors are electrochemical capacitors that have an unusually high energy density when compared to common capacitors, typically on the order of thousands of times greater than a high-capacity electrolytic capacito...
0.01 98.5%90%
Capacitor
Capacitor

A capacitor or condenser is a Passive component electronic component consisting of a pair of electrical conductor separated by a dielectric....
0.002  
Water at 100 m dam height
Hydroelectricity

Hydroelectricity is electricity generated by hydropower, i.e., the production of power through use of the gravitational force of falling or flowing water....
0.0010.001 8585-90%
Spring power (clock spring), torsion spring
Torsion spring

A torsion spring is a spring that works by Torsion or twisting; that is, a flexible Elasticity object that stores mechanical energy when it is twisted....
0.0003 0.0006  
Storage typeEnergy density by mass (MJ/kg)Energy density by volume (MJ/L
Litér

Lit?r is a village in Veszpr?m , Hungary.External links ...
)		Peak recovery efficiency %Practical recovery efficiency %


Energy densities excluding oxidisers


This table lists energy densities of fuels that require external oxidisers, such as oxygen. These figures do not take into account the mass and volume of the oxygen required for the chemical reactions, as it is assumed to be freely available and present in the atmosphere. Such systems give a higher energy density than an equivalent system that must hold its own oxidiser.

ANFO
ANFO

ANFO is a widely used explosive mixture. The oil used is most often Heating oil, or diesel fuel, but sometimes kerosene, coal dust, or even molasses....
>
Energy Densities Table
Storage typeEnergy density by mass (MJ/kg)Energy density by volume (MJ/L
Litér

Lit?r is a village in Veszpr?m , Hungary.External links ...
)		Peak recovery efficiency %Practical recovery efficiency %
Hydrogen, liquid
Liquid hydrogen

Liquid hydrogen is the liquid state of the element hydrogen. Hydrogen is found naturally in the molecule H2 form.To exist as a liquid, H2 must be pressurized and cooled to a very low temperature, 20.28 K ....
 (burned in air)		14310.1  
Hydrogen, compressed at 700 bar (burned in air) 1435.6  
Hydrogen, gas (burned in air)1430.01079  
Beryllium
Beryllium

Beryllium is a chemical element with the symbol Be and atomic number 4.A Bivalent element, beryllium is found naturally only combined with other elements in minerals....
 (toxic) (burned in air)		67.6125.1  
Lithium borohydride
Lithium borohydride

Lithium borohydride is known in organic synthesis as a reducing agent for esters.It is also renowned for one of the highest energy density chemical energy carriers....
 (burned in air)		65.243.4  
Boron
Boron

Boron is a chemical element with atomic number 5 and the chemical symbol B. Boron is a trivalent metalloid element which occurs abundantly in the evaporite ores borax and ulexite....
  (burned in air)		58.9137.8  
Methane
Methane

Methane is a chemical compound with the molecular formula . It is the simplest alkane, and the principal component of natural gas. Methane's bond angles are 109.5 degrees....
 (1.013bar, 15°C) (burned in air)		55.60.0378  
Natural gas
Natural gas

Natural gas is a gas consisting primarily of methane. It is found associated with fossil fuels, in coal beds, as methane clathrates, and is created by methanogenic organisms in marshes, bogs, and landfills....
 (burned in air)		53.610  
LPG propane
Propane

Propane is a three-carbon alkane, normally a gas, but compressible to a transportable liquid. It is derived from other petroleum products during oil or natural gas processing....
 (burned in air)		49.625.3  
LPG butane
Butane

Butane, also called n-butane, is the unbranched alkane with four carbon atoms, CH3CH2CH2CH3....
 (burned in air)		49.127.7  
Gasoline
Gasoline

File:GasCan.jpgGasoline or petrol is a petroleum-derived liquid mixture, primarily used as fuel in internal combustion engines.It consists mostly of aliphatic hydrocarbons, enhanced with iso-octane or the aromatic hydrocarbons toluene and benzene to increase its octane rating....
46.434.2  
Diesel fuel/residential heating oil
Heating oil

Heating oil, or oil heat is a low viscosity, flammable liquid petroleum product used to fuel building furnaces or boilers.Heating oil is commonly delivered by tank truck to residential, commercial and municipal buildings and stored in above-ground storage tanks located in the basements, garages, or outside adjacent to the building....
 (burned in air)		46.237.3  
Polyethylene
Polyethylene

Polyethylene or polythene is a thermoplastic commodity heavily used in consumer products . Over 60 million tons of the material are produced worldwide every year....
 plastic		46.342.6  
Polypropylene
Polypropylene

Polypropylene or polypropene is a thermoplastic polymer, made by the chemical industry and used in a wide variety of applications, including packaging, textiles , stationery, plastic parts and reusable containers of various types, laboratory equipment, loudspeakers, automotive components, and polymer banknotes....
 plastic		46.441.7  
Gasohol E10 (10% ethanol 90% gasoline by volume)43.5433.72  
Gasohol E85
E85

E85 is an alcohol fuel mixture that typically contains a mixture of up to 85% Methylated spirit fuel Ethanol fuel and gasoline or other hydrocarbon by volume....
 (85% ethanol 10% gasoline by volume)		33.125.65  
Lithium
Lithium

Lithium is a chemical element with the symbol Li and atomic number 3. It is a soft alkali metal with a silver-white color. Under standard conditions for temperature and pressure, it is the lightest metal and the least dense solid element....
 (burned in air)		43.123.0  
Jet A
Jet fuel

Jet fuel is a type of aviation fuel designed for use in aircraft powered by Aircraft engine#Gas turbine engine configurations. It is clear to straw colored....
 aviation fuel
Aviation fuel

Aviation fuel is a specialized type of petroleum-based fuel used to power aircraft. It is generally of a higher quality than fuels used in less critical applications such as heating or road transport, and often contains additives to reduce the risk of icing or explosion due to high temperatures, amongst other properties....
  / kerosene
Kerosene

Kerosene, sometimes spelled kerosine in scientific and industrial usage, also known as paraffin, is a combustible hydrocarbon liquid....
42.833  
Biodiesel
Biodiesel

Biodiesel refers to a non-petroleum-based diesel fuel consisting of long chain alkyl esters, made by transesterification of vegetable oil or animal fat , which can be used in unmodified diesel-engine vehicles....
 oil (vegetable oil)		42.2033  
DMF
2,5-Dimethylfuran

A derivative of furan, 2,5-Dimethylfuran is a heterocyclic compound of the formula C6H8O. While it may be abbreviated DMF it should not be confused with dimethylformamide....
 (2,5-dimethylfuran) 		42 37.8  
Crude oil (according to the definition of ton of oil equivalent
Ton of oil equivalent

The tonne of oil equivalent is a units of energy: the amount of energy released by burning one tonne of crude oil, approximately 42 joule .The toe is sometimes used for large amounts of energy, as it can be more intuitive to visualise, say, the energy released by burning 1000 tonnes of oil than 42,000 1000000000 joules ....
)		46.337  
Polystyrene
Polystyrene

Polystyrene , sometimes abbreviated PS, is an Aromaticity polymer made from the aromatic monomer styrene, a liquid hydrocarbon that is commercially manufactured from petroleum by the chemical industry....
 plastic		41.443.5  
Body fat metabolism
Fatty acid metabolism

Fatty acids are an important source of energy for many organisms. Excess glucose can be stored efficiently as fat. Triglycerides yield more than twice as much energy for the same mass as do carbohydrates or proteins....
383522 
Butanol
Butanol fuel

Butanol may be used as a fuel in an internal combustion engine. Because its longer hydrocarbon chain causes it to be fairly Chemical polarity, it is more similar to gasoline than it is to ethanol....
36.629.2  
Graphite
Graphite

The mineral graphite is one of the allotropes of carbon. It was named by Abraham Gottlob Werner in 1789 from the Greek language ??afe?? : "to draw/write", for its use in pencils, where it is commonly called lead, as distinguished from the actual metallic element lead....
 (burned in air)		32.772.9  
coal
Coal

Coal is a readily combustion black or brownish-black sedimentary rock. The harder forms, such as anthracite, can be regarded as metamorphic rock because of later exposure to elevated temperature and pressure....
, Anthracite		32.572.4 36
Silicon
Silicon

Silicon is the most common metalloid. It is a chemical element, which has the symbol Si and atomic number 14. The atomic mass is 28.0855....
 (burned in air)		32.275.1  
Aluminum (burned in air)31.083.8  
Ethanol
Ethanol

Ethanol, also called ethyl alcohol, pure alcohol, grain alcohol, or drinking alcohol, is a volatility , flammable, colorless liquid....
3024  
Polyester
Polyester

Polyester is a category of polymers which contain the ester functional group in their main chain. Although there are many polyesters, the term "polyester" as a specific material most commonly refers to polyethylene terephthalate ....
 plastic		26.0 35.6  
Magnesium
Magnesium

Magnesium is a chemical element with the symbol Mg, atomic number 12, atomic weight 24.3050 and common oxidation number +2.Magnesium, an alkaline earth metal, is the ninth most abundance of the chemical elements in the universe by mass....
 (burned in air)		24.743.0  
coal
Coal

Coal is a readily combustion black or brownish-black sedimentary rock. The harder forms, such as anthracite, can be regarded as metamorphic rock because of later exposure to elevated temperature and pressure....
, Bituminous
Bitumen

Bitumen is a mixture of organic compounds liquids that are highly viscous, black, sticky, entirely soluble in carbon disulfide, and composed primarily of highly condensed polycyclic aromatic hydrocarbons....
  		2420  
PET
Polyethylene terephthalate

Polyethylene tephthalate , commonly abbreviated PET, PETE, or the obsolete PETP or PET-P), is a thermoplastic polymer resin of the polyester family and is used in synthetic fibers; beverage, food and other liquid Packaging; thermoforming applications; and engineering resins often in combination with glass fiber....
 plastic		23.5 (impure)  
Methanol
Methanol

Methanol, also known as methyl alcohol, carbinol, wood alcohol, wood naphtha or wood spirits, is a chemical compound with chemical formula carbonhydrogen3oxygenhydrogen ....
19.715.6  
Hydrazine
Hydrazine

Hydrazine is a chemical compound with the chemical formula N2H4. It is a colourless liquid with an ammonia-like odor and is derived from the same industrial chemistry processes that manufacture ammonia....
 (toxic) combusted to N2+H2O		19.519.3  
Liquid ammonia
Ammonia

Ammonia is a chemical compound with the chemical formula nitrogenhydrogen. It is normally encountered as a gas with a characteristic pungent odor....
 (combusted to N2+H2O)		18.611.5  
PVC
PVC

Polyvinyl chloride is a plastic.PVC may also refer to:*Param Vir Chakra, India's highest military honor*Peripheral venous catheter*Permanent virtual circuit, a term used in telecommunications and computer networks...
 plastic (improper combustion toxic
Polyvinyl chloride

Polyvinyl chloride, commonly abbreviated PVC, is the third most widely used thermoplastic polymer after polyethylene and polypropylene....
)		18.025.2  
Sugars, carbohydrates & protein metabolism
Fatty acid metabolism

Fatty acids are an important source of energy for many organisms. Excess glucose can be stored efficiently as fat. Triglycerides yield more than twice as much energy for the same mass as do carbohydrates or proteins....
1726.2(dextrose)2222  
coal
Coal

Coal is a readily combustion black or brownish-black sedimentary rock. The harder forms, such as anthracite, can be regarded as metamorphic rock because of later exposure to elevated temperature and pressure....
, Lignite
Lignite

Lignite, often referred to as brown coal, or Rosebud coal by Northern Pacific Railroad,is a soft brown fuel with characteristics that put it somewhere between coal and peat....
14.0  
Calcium
Calcium

Calcium is the chemical element with the symbol Ca and atomic number 20. It has an atomic mass of 40.078 amu. Calcium is a soft grey alkaline earth metal, and is the fifth most abundant element by mass in the earth's Crust ....
 (burned in air)		15.924.6  
Glucose
Glucose

Glucose , a monosaccharide also known as grape sugar, blood sugar, or corn sugar, is a very important carbohydrate in biology....
15.5523.9  
Dry cowdung and cameldung
Manure

Manure is organic matter used as organic fertilizer in agriculture. Manures contribute to the fertility of the soil by adding organic matter and Nutrient#Nutrients and the environment, such as nitrogen that is trapped by bacterium in the soil....
15.5  
Wood
Wood

Wood is an organic material; in the strict sense wood is produced as secondary xylem in the stems of woody plants, notably trees but also shrubs, etc....
6.0  
Sodium
Sodium

Sodium is an element which has the symbol Na , atomic number 11, atomic mass 23 amu , and a common oxidation number +1. Sodium is a soft, silvery white, highly reactive element and is a member of the alkali metals within "group 1" ....
 (burned to wet sodium hydroxide
Sodium hydroxide

Sodium hydroxide , also known as lye, caustic soda and sodium hydrate, is a caustic metallic Base . Sodium hydroxide forms a strong alkaline solution when dissolved in a solvent such as water, however, only the hydroxide ion is basic....
)		13.312.8  
Household waste8.0  
Sodium
Sodium

Sodium is an element which has the symbol Na , atomic number 11, atomic mass 23 amu , and a common oxidation number +1. Sodium is a soft, silvery white, highly reactive element and is a member of the alkali metals within "group 1" ....
 (burned to dry sodium oxide
Sodium oxide

Sodium oxide is a chemical compound with the formula Sodium2Oxygen. It is used in ceramics and glasses. Treatment with water affords sodium hydroxide....
)		9.18.8  
Zinc
Zinc

Zinc is a metallic chemical element with the symbol Zn and atomic number 30. It is a first-row transition metal of the group 12 element of the periodic table....
 (burned in air)		5.338.0  
Teflon plastic (combustion toxic, but flame retardant)5.111.2  
iron
Iron

Iron is a chemical element with the symbol Fe and atomic number 26. Iron is a Group 8 element and period 4 element. Iron is lustrous and silvery in color....
 (burned to iron(III) oxide
Iron(III) oxide

Iron oxide?also known as ferric oxide, Hematite, red iron oxide, synthetic maghemite, colcothar, or simply rust?is one of the several oxide Chemical compounds of iron, and has Paramagnetism properties....
)		5.240.68  
iron
Iron

Iron is a chemical element with the symbol Fe and atomic number 26. Iron is a Group 8 element and period 4 element. Iron is lustrous and silvery in color....
 (burned to iron(II) oxide
Iron(II) oxide

Iron oxide, also known as ferrous oxide, iron oxide/oxidized iron or more commonly rusted iron, is one of the iron oxides. It is a black-colored powder with the chemical formula ....
)		4.938.2  
3.7  
battery, Zinc air
Zinc-air battery

Zinc-air batteries , and zinc-air fuel cells, are Battery powered by the oxidation of zinc with oxygen from the air. These batteries have high energy density and are relatively inexpensive to produce....
 (wiki 1)		1.33   
battery, Zinc air (wiki 2)0.40.405.95.9  
Storage typeEnergy density by mass (MJ/kg)Energy density by volume (MJ/L
Litér

Lit?r is a village in Veszpr?m , Hungary.External links ...
)		Peak recovery efficiency %Practical recovery efficiency %


Energy density of electric and magnetic fields


Electric
Electric field

In physics, the space surrounding an electric charge or in the presence of a time-varying magnetic field has a property called an electric field ....
 and magnetic field
Magnetic field

A magnetism field is a vector field which can exert a magnetic force on moving electric charges and on magnetic dipoles . When placed in a magnetic field, magnetic dipoles tend to align their axes parallel to the magnetic field....
s store energy. In a vacuum, the (volumetric) energy density (in SI units) is given by

,

where E is the electric field
Electric field

In physics, the space surrounding an electric charge or in the presence of a time-varying magnetic field has a property called an electric field ....
 and B is the magnetic field
Magnetic field

A magnetism field is a vector field which can exert a magnetic force on moving electric charges and on magnetic dipoles . When placed in a magnetic field, magnetic dipoles tend to align their axes parallel to the magnetic field....
. In the context of magnetohydrodynamics
Magnetohydrodynamics

Magnetohydrodynamics is the academic discipline which studies the dynamics of electrical conduction fluids. Examples of such fluids include Plasma , liquid metals, and Brine....
, the physics of conductive fluids, the magnetic energy density behaves like an additional pressure
Pressure

Pressure is the force per unit area applied to an object in a direction surface normal to the surface. Gauge pressure is the pressure relative to the local atmospheric or ambient pressure....
 that adds to the gas pressure of a plasma
Plasma (physics)

In physics and chemistry, plasma is a partially ionized gas, in which a certain proportion of electrons are free rather than being bound to an atom or molecule....
.

In normal (linear) substances, the energy density (in SI units) is

,

where D is the electric displacement field
Electric displacement field

In physics, the electric displacement field is a vector field that appears in Maxwell's equations. It accounts for the effects of bound state electric charge within materials....
 and H is the magnetizing field
Magnetic field

A magnetism field is a vector field which can exert a magnetic force on moving electric charges and on magnetic dipoles . When placed in a magnetic field, magnetic dipoles tend to align their axes parallel to the magnetic field....
.

Energy density of empty space


In physics
Physics

Physics is the natural science which examines basic concepts such as energy, force, and spacetime and all that derives from these, such as mass, charge, matter and its Motion ....
, "vacuum energy
Vacuum energy

Vacuum energy is an underlying background energy that exists in space even when devoid of matter . The vacuum energy is deduced from the concept of Virtual particle#Virtual particles in the vacuum, which are themselves derived from the Uncertainty principle#Energy-time uncertainty principle....
" or "zero-point energy
Zero-point energy

In physics, the zero-point energy is the lowest possible energy that a quantum mechanical physical system may have and is the energy of the ground state....
" is the volumetric energy density of empty space. More recent developments have expounded on the concept of energy in empty space.

Modern physics
Modern physics

The term modern physics refers to the post-classical physics of physics. The term implies that classical physics of phenomena are lacking, and that an accurate, "modern", description of reality requires theories to incorporate elements of quantum mechanics or theory of relativity, or both....
 is commonly classified into two fundamental theories: quantum field theory
Quantum field theory

Quantum field theory or QFT provides a theoretical framework for constructing quantum mechanics models of systems classically described by field or of Many-body problem....
 and general relativity
General relativity

General relativity or the general theory of relativity is the Geometry Theoretical physics of gravitation published by Albert Einstein in 1916....
. Quantum field theory takes quantum mechanics
Quantum mechanics

Quantum mechanics is a set of principles underlying the most fundamental known description of all physical systems at the microscopic scale . Notable amongst these principles are both a dual wave-like and particle-like behavior of matter and radiation, and prediction of probabilities in situations where classical physics predicts certaintie...
 and special relativity
Special relativity

Special relativity is the physical theory of measurement in inertial frames of reference proposed in 1905 by Albert Einstein in the paper "Annus Mirabilis Papers#Special relativity"....
 into account, and it's a theory of all the forces and particles except gravity. General relativity is a theory of gravity, but it is incompatible with quantum mechanics. Currently these two theories have not yet been reconciled into one unified description, though research into "quantum gravity
Quantum gravity

Quantum gravity is the field of theoretical physics attempting to unify quantum mechanics, which describes three of the Fundamental interaction , with general relativity, the theory of the fourth fundamental force: Gravitation....
" seeks to bridge this divide.

In general relativity
General relativity

General relativity or the general theory of relativity is the Geometry Theoretical physics of gravitation published by Albert Einstein in 1916....
, the cosmological constant
Cosmological constant

In physical cosmology, the cosmological constant was proposed by Albert Einstein as a modification of his original theory of general relativity to achieve a Einstein's universe....
 is proportional to the energy density of empty space, and can be measured by the curvature of space. It is subsequently related to the age of the universe, and as energy expands outwards with time its density changes.

Quantum field theory considers the vacuum ground state not to be completely empty, but to consist of a seething mass of virtual particle
Virtual particle

In physics, a virtual particle is a particle that exists for a limited time and space, introducing uncertainty in their energy and momentum due to the Heisenberg Uncertainty Principle....
s and fields
Field (physics)

In physics, a field is a physical quantity associated to each point of spacetime. A field can be classified as a scalar field, a vector field, or a tensor field, according to whether the value of the field at each point is a scalar , a vector , or, more generally, a tensor, respectively....
. These fields are quantified as probabilities—that is, the likelihood of manifestation based on conditions. Since these fields do not have a permanent existence, they are called vacuum fluctuations. In the Casimir effect
Casimir effect

In physics, the Casimir effect and the Casimir-Polder force are physical force arising from a quantum field theory. The typical example is of two electric charge metallic plates in a vacuum, placed a few micrometers apart, without any external electromagnetic field....
, two metal plates can cause a change in the vacuum energy density between them which generates a measurable force.

Some believe that vacuum energy might be the "dark energy
Dark energy

In physical cosmology & astronomy dark energy is a hypothetical form of energy that permeates all of space and tends to increase the Hubble's law....
" (also called Quintessence
Quintessence (physics)

In physics, quintessence is a hypothesis form of dark energy postulated as an explanation of observations of an accelerating universe....
) associated with the cosmological constant in general relativity, thought to be similar to a negative force of gravity (or antigravity). Observations that the expanding universe appears to be accelerating seem to support the cosmic inflation
Cosmic inflation

In physical cosmology, cosmic inflation is the hypothesis that the wiktionary:nascent universe passed through a phase of exponential growth metric expansion of space was driven by a negative pressure vacuum energy density....
 theory—first proposed by Alan Guth
Alan Guth

Alan Harvey Guth is a theoretical physicist and cosmologist. Guth has researched elementary particle theory .He graduated from the Massachusetts Institute of Technology in 1968 in physics and stayed to receive a master's and a doctorate, also in physics....
 in 1981—in which the nascent universe passed through a phase of exponential expansion driven by a negative vacuum energy density (positive vacuum pressure).

Energy density of food

Energy density is the amount of energy (kilojoules or calorie
Calorie

The calorie is a pre-SI metric system unit of energy. The unit was first defined by Professor Nicolas Cl?ment in 1824 as a unit of heat. This definition entered French and English dictionaries between 1841 and 1867....
s) per amount of food, with food amount being measured in grams or milliliters of food. Energy density is thus expressed in cal/g, kcal/g, J/g, kJ/g, cal/mL, kcal/mL, J/mL, or kJ/mL. What is popularly referred to as the number of "Calories" in a portion of food (invariably spelled with a capital C to show that it is the food Calorie) is therefore the number of kilocalories (thousands of calories with the small c) in the portion.

Energy density measures the energy released when the food is metabolised by a healthy organism when it ingests the food (see food energy
Food energy

Food energy is the amount of energy in food that is available through digestion.Like other forms of energy, food energy is expressed in calories or joules....
 for calculation) and the food is metabolized with oxygen, into waste products such as carbon dioxide
Carbon dioxide

Carbon dioxide is a chemical compound composed of two oxygen atoms covalent bond to a single carbon atom. It is a gas at standard temperature and pressure and exists in Earth's atmosphere in this state....
 and water. Carbohydrate
Carbohydrate

Carbohydrates or saccharides are the most abundant of the four major classes of biomolecules. They fill numerous roles in living things, such as the storage and transport of energy and structural components ....
s, fat
Fat

Fats consist of a wide group of compounds that are generally soluble in organic solvents and largely insoluble in water. Chemistry, fats are generally ester of glycerol and fatty acids....
s, and protein
Protein

Proteins are organic compounds made of amino acids arranged in a linear chain and joined together by peptide bonds between the carboxyl and amino groups of adjacent amino acid Residue ....
s are the only sources of energy for an individual abstaining from alcohol
Ethanol

Ethanol, also called ethyl alcohol, pure alcohol, grain alcohol, or drinking alcohol, is a volatility , flammable, colorless liquid....
, and they make up ninety percent of the dry weight of food. Therefore, water
Water

Water is a common chemical substance that is essential for the survival of all known forms of life. In typical usage, water refers only to its liquid form or States of matter, but the substance also has a solid state, ice, and a gaseous state, water vapor or steam....
 content is the most important factor in energy density. Carbohydrates and proteins provide four calories per gram, whereas fat provides nine calories per gram, 2.25 times as much energy. Foods that derive most of their energy from fat have a much higher energy density than those that derive most of their energy from carbohydrates or proteins, even if the water content is the same. Nutrients with a lower absorption, such as fiber
Fiber

Fiber or fibre is a class of materials that are continuous filaments or are in discrete elongated pieces, similar to lengths of yarn. They are very important in the biology of both plants and animals, for holding tissue s together....
 or sugar alcohol
Sugar alcohol

A sugar alcohol is a hydrogenation form of carbohydrate, whose carbonyl group has been reduced to a primary or secondary hydroxyl group . Sugar alcohols have the general formula Hn+1H, whereas sugars have HnHCO....
s, lower the energy density of foods as well. A moderate energy density would be 1.6 to 3 calories per gram; salmon, lean meat, and bread would fall in this category. High-energy foods would have more than three calories per gram and include crackers, cheese, dark chocolate, and peanuts. The energy density of a food can be determined from the label by dividing the calories or joules by the weight in grams.

Miscellaneous

  • Kinetic energy
    Kinetic energy

    The kinetic energy of an object is the extra energy which it possesses due to its motion. It is defined as the mechanical work needed to accelerate a body of a given mass from rest to its current velocity....
     per unit mass: J/kg, where v is the speed
    Speed

    Speed is the rate of Motion , or equivalently the rate of change of distance.Speed is a Scalar quantity with dimensions length/time; the equivalent Vector quantity to speed is velocity....
     in m/s. See also kinetic energy per unit mass of projectiles
    Projectile

    A projectile is any object propelled through space by the exertion of a force, which ceases after launch. In a general sense, even a Football or baseball may be considered a projectile....
    .
  • Potential energy
    Potential energy

    Potential energy can be thought of as energy stored within a physical system. It is called potential energy because it has the potential to be converted into other forms of energy, such as kinetic energy, and to do Mechanical work in the process....
     with respect to gravity, close to earth, per unit mass: ca. 9.8 h J/kg, with h the height in m.
  • Heat
    Heat

    In physics and thermodynamics, heat is any transfer of energy from one body or thermodynamic system to another due to a difference in temperature....
    : energies per unit mass are specific heat capacity
    Specific heat capacity

    Specific heat capacity, also known simply as specific heat, is the measure of the energy required to increase the temperature of a of a substance by a certain Celsius#Temperatures_and_intervals....
     times temperature
    Temperature

    In physics, temperature is a physical property of a Physical system that underlies the common notions of hot and cold; something that feels hotter generally has the greater temperature....
     difference, and specific melting heat
    Latent heat

    In thermochemistry, latent heat is the amount of energy in the form of heat released or absorbed by a chemical substance during a change of state of matter , or a phase transition....
    , and specific heat of vaporization
    Standard enthalpy change of vaporization

    The enthalpy of vaporization, , also known as the heat of vaporization or heat of evaporation, is the energy required to transform a given quantity of a substance into a gas....


See also

  • Figure of merit
    Figure of merit

    A figure of merit is a quantity used to characterize the performance of a device, system or method, relative to its alternatives. In engineering, figures of merit are often defined for particular materials or devices in order to determine their relative utility for an application....
  • Energy content of biofuel
    Energy content of biofuel

    A Table of Energy Content and CO2 Output of Common Fuels Energy is the ability to do work. Per kilogram of mass, different substances can do different amounts of work....
  • Heat of combustion
    Heat of combustion

    The heat of combustion is the energy released as heat when one mol of a compound undergoes complete combustion with oxygen. The chemical reaction is typically a hydrocarbon reacting with oxygen to form carbon dioxide, water and heat....
  • Heating value
  • Rechargeable battery
    Rechargeable battery

    File:Energizer reghargeble batteryIMG 0006.JPGA rechargeable battery, also known as a storage battery, is a group of two or more electrochemical cell....
  • Specific impulse
    Specific impulse

    Specific impulse is a way to describe the efficiency of rocket engine and jet engine engines. It represents the impulse per unit of propellant....
  • Vacuum energy
    Vacuum energy

    Vacuum energy is an underlying background energy that exists in space even when devoid of matter . The vacuum energy is deduced from the concept of Virtual particle#Virtual particles in the vacuum, which are themselves derived from the Uncertainty principle#Energy-time uncertainty principle....


External references


Zero point energy

  1. Eric Weisstein's world of physics: energy density
  2. Baez physics: Is there a nonzero cosmological constant? ; .
  3. Introductory review of cosmic inflation
  4. An exposition to inflationary cosmology


Density data

  • "Aircraft Fuels." Energy, Technology and the Environment Ed. Attilio Bisio. Vol. 1. New York: John Wiley and Sons, Inc., 1995. 257-259


  • “” - Dr. James J. Eberhardt - Energy Efficiency and Renewable Energy, U.S. Department of Energy - 2002 Diesel Engine Emissions Reduction (DEER) Workshop San Diego, California - August 25 - 29, 2002


Energy storage



Books

  • The Inflationary Universe: The Quest for a New Theory of Cosmic Origins by Alan H. Guth (1998) ISBN 0-201-32840-2
  • Cosmological Inflation and Large-Scale Structure by Andrew R. Liddle, David H. Lyth (2000) ISBN 0-521-57598-2
  • Richard Becker, "Electromagnetic Fields and Interactions", Dover Publications Inc., 1964


Footnotes