Energy density
{{Short description|Energy per volume}}
{{Infobox physical quantity
| name = Energy density
| otherunits = J/L, W⋅h/L, Pa
| basequantities = kg⋅m−1⋅s−2
| symbols =
| dimension = wikidata
}}
In physics, energy density is the quotient between the amount of energy stored in a given system or contained in a given region of space and the volume of the system or region considered. Often only the useful or extractable energy is measured. It is sometimes confused with stored energy per unit mass, which is called specific energy or {{em|gravimetric energy density}}.
There are different types of energy stored, corresponding to a particular type of reaction. In order of the typical magnitude of the energy stored, examples of reactions are: nuclear, chemical (including electrochemical), electrical, pressure, material deformation or in electromagnetic fields. Nuclear reactions take place in stars and nuclear power plants, both of which derive energy from the binding energy of nuclei. Chemical reactions are used by organisms to derive energy from food and by automobiles from the combustion of gasoline. Liquid hydrocarbons (fuels such as gasoline, diesel and kerosene) are today the densest way known to economically store and transport chemical energy at a large scale (1 kg of diesel fuel burns with the oxygen contained in ≈ 15 kg of air). Burning local biomass fuels supplies household energy needs (cooking fires, oil lamps, etc.) worldwide. Electrochemical reactions are used by devices such as laptop computers and mobile phones to release energy from batteries.
Energy per unit volume has the same physical units as pressure, and in many situations is synonymous. For example, the energy density of a magnetic field may be expressed as and behaves like a physical pressure. The energy required to compress a gas to a certain volume may be determined by multiplying the difference between the gas pressure and the external pressure by the change in volume. A pressure gradient describes the potential to perform work on the surroundings by converting internal energy to work until equilibrium is reached.
In cosmological and other contexts in general relativity, the energy densities considered relate to the elements of the stress–energy tensor and therefore do include the rest mass energy as well as energy densities associated with pressure.
Chemical energy
When discussing the chemical energy contained, there are different types which can be quantified depending on the intended purpose. One is the theoretical total amount of thermodynamic work that can be derived from a system, at a given temperature and pressure imposed by the surroundings, called exergy. Another is the theoretical amount of electrical energy that can be derived from reactants that are at room temperature and atmospheric pressure. This is given by the change in standard Gibbs free energy. But as a source of heat or for use in a heat engine, the relevant quantity is the change in standard enthalpy or the heat of combustion.
There are two kinds of heat of combustion:
- The higher value (HHV), or gross heat of combustion, includes all the heat released as the products cool to room temperature and whatever water vapor is present condenses.
- The lower value (LHV), or net heat of combustion, does not include the heat which could be released by condensing water vapor, and may not include the heat released on cooling all the way down to room temperature.
A convenient table of HHV and LHV of some fuels can be found in the references.{{cite web |url=https://www.engineeringtoolbox.com/fossil-fuels-energy-content-d_1298.html |title=Fossil and Alternative Fuels – Energy Content (2008). |publisher=Engineering ToolBox |access-date=2018-10-08 |archive-date=2018-10-09 |archive-url=https://web.archive.org/web/20181009013225/https://www.engineeringtoolbox.com/fossil-fuels-energy-content-d_1298.html |url-status=live }}
= In energy storage and fuels =
[[File:Energy density.svg|thumb|400px|Selected energy densities plot{{cite web
| url=https://hypertextbook.com/facts/2003/JuliyaFisher.shtml
| title=Energy density of coal
| first=Julia
| last=Fisher
| year=2003
| website=The Physics Factbook
| editor-last=Elert
| editor-first=Glenn
| accessdate=2019-07-28
| archive-date=2019-07-28
| archive-url=https://web.archive.org/web/20190728163904/https://hypertextbook.com/facts/2003/JuliyaFisher.shtml
| url-status=live
For energy storage, the energy density relates the stored energy to the volume of the storage equipment, e.g. the fuel tank. The higher the energy density of the fuel, the more energy may be stored or transported for the same amount of volume. The energy of a fuel per unit mass is called its specific energy.
The adjacent figure shows the gravimetric and volumetric energy density of some fuels and storage technologies (modified from the Gasoline article). Some values may not be precise because of isomers or other irregularities. The heating values of the fuel describe their specific energies more comprehensively.
The density values for chemical fuels do not include the weight of the oxygen required for combustion. The atomic weights of carbon and oxygen are similar, while hydrogen is much lighter. Figures are presented in this way for those fuels where in practice air would only be drawn in locally to the burner. This explains the apparently lower energy density of materials that contain their own oxidizer (such as gunpowder and TNT), where the mass of the oxidizer in effect adds weight, and absorbs some of the energy of combustion to dissociate and liberate oxygen to continue the reaction. This also explains some apparent anomalies, such as the energy density of a sandwich appearing to be higher than that of a stick of dynamite.
Given the high energy density of gasoline, the exploration of alternative media to store the energy of powering a car, such as hydrogen or battery, is strongly limited by the energy density of the alternative medium. The same mass of lithium-ion storage, for example, would result in a car with only 2% the range of its gasoline counterpart. If sacrificing the range is undesirable, much more storage volume is necessary. Alternative options are discussed for energy storage to increase energy density and decrease charging time, such as supercapacitors.{{cite journal|last1=Ionescu-Zanetti|first1=C.|last2=et.|first2=al.|s2cid=120910476|title=Nanogap capacitors: Sensitivity to sample permittivity changes|journal=Journal of Applied Physics|date=2005|volume=99|issue=2|pages=024305–024305–5|doi=10.1063/1.2161818|bibcode=2006JAP....99b4305I}}{{cite journal|last1=Naoi|first1=K.|last2=et.|first2=al.|title=New generation "nanohybrid supercapacitor".|journal=Accounts of Chemical Research|volume=46|issue=5|pages=1075–1083|date=2013|doi=10.1021/ar200308h|pmid=22433167}}{{cite journal|last1=Hubler|first1=A.|last2=Osuagwu|first2=O.|s2cid=6994736|title=Digital quantum batteries: Energy and information storage in nanovacuum tube arrays|journal=Complexity|date=2010|volume=15|issue=5|pages=NA|doi=10.1002/cplx.20306|doi-access=free}}{{cite journal|last1=Lyon|first1=D.|last2=et.|first2=al.|title=Gap size dependence of the dielectric strength in nano vacuum gaps|journal=IEEE Transactions on Dielectrics and Electrical Insulation|date=2013|volume=2|issue=4|pages=1467–1471|doi=10.1109/TDEI.2013.6571470|s2cid=709782}}
No single energy storage method boasts the best in specific power, specific energy, and energy density. Peukert's law describes how the amount of useful energy that can be obtained (for a lead-acid cell) depends on how quickly it is pulled out.
= Efficiency =
In general an engine will generate less kinetic energy due to inefficiencies and thermodynamic considerations—hence the specific fuel consumption of an engine will always be greater than its rate of production of the kinetic energy of motion.
Energy density differs from energy conversion efficiency (net output per input) or embodied energy (the energy output costs to provide, as harvesting, refining, distributing, and dealing with pollution all use energy). Large scale, intensive energy use impacts and is impacted by climate, waste storage, and environmental consequences.
Nuclear energy
The greatest energy source by far is matter itself, according to the mass–energy equivalence. This energy is described by {{nowrap|1=E = mc2}}, where c is the speed of light. In terms of density, {{nowrap|1=m = ρV}}, where ρ is the volumetric mass density, V is the volume occupied by the mass. This energy can be released by the processes of nuclear fission (~ 0.1%), nuclear fusion (~ 1%), or the annihilation of some or all of the matter in the volume V by matter–antimatter collisions (100%).{{citation needed|date=November 2018}}
The most effective ways of accessing this energy, aside from antimatter, are fusion and fission. Fusion is the process by which the sun produces energy which will be available for billions of years (in the form of sunlight and heat). However as of 2024, sustained fusion power production continues to be elusive. Power from fission in nuclear power plants (using uranium and thorium) will be available for at least many decades or even centuries because of the plentiful supply of the elements on earth,{{cite web |date=2014-10-08 |title=Supply of Uranium |url=http://www.world-nuclear.org/info/Nuclear-Fuel-Cycle/Uranium-Resources/Supply-of-Uranium/ |url-status=dead |archive-url=https://web.archive.org/web/20151017065906/http://www.world-nuclear.org/info/Nuclear-Fuel-Cycle/Uranium-Resources/Supply-of-Uranium/ |archive-date=2015-10-17 |access-date=2015-06-13 |publisher=world-nuclear.org}} though the full potential of this source can only be realized through breeder reactors, which are, apart from the BN-600 reactor, not yet used commercially.{{cite web |date=2007-01-26 |title=Facts from Cohen |url=http://www-formal.stanford.edu/jmc/progress/cohen.html |url-status=dead |archive-url=https://web.archive.org/web/20070410165316/http://www-formal.stanford.edu/jmc/progress/cohen.html |archive-date=2007-04-10 |access-date=2010-05-07 |publisher=Formal.stanford.edu}}
= Fission reactors =
Nuclear fuels typically have volumetric energy densities at least tens of thousands of times higher than chemical fuels. A 1 inch tall uranium fuel pellet is equivalent to about 1 ton of coal, 120 gallons of crude oil, or 17,000 cubic feet of natural gas.{{cite web |last1=Venditti |first1=Bruno |last2=Content |first2=Sponsored |date=2021-08-27 |title=The Power of a Uranium Pellet |url=https://elements.visualcapitalist.com/the-power-of-a-uranium-pellet/ |access-date=2024-08-11 |website=Elements by Visual Capitalist |archive-date=2024-08-11 |archive-url=https://web.archive.org/web/20240811181153/https://elements.visualcapitalist.com/the-power-of-a-uranium-pellet/ |url-status=live }} In light-water reactors, 1 kg of natural uranium – following a corresponding enrichment and used for power generation– is equivalent to the energy content of nearly 10,000 kg of mineral oil or 14,000 kg of coal.{{cite web |date=2019-05-22 |title=Fuel comparison |url=https://www.euronuclear.org/glossary/fuel-comparison/ |access-date=2024-08-11 |website=ENS |archive-date=2024-08-11 |archive-url=https://web.archive.org/web/20240811181154/https://www.euronuclear.org/glossary/fuel-comparison/ |url-status=live }} Comparatively, coal, gas, and petroleum are the current primary energy sources in the U.S.{{cite web |date=2009-06-26 |title=U.S. Energy Information Administration (EIA) - Annual Energy Review |url=http://www.eia.doe.gov/emeu/aer/pecss_diagram.html |archive-url=https://web.archive.org/web/20100506022627/http://www.eia.doe.gov/emeu/aer/pecss_diagram.html |archive-date=2010-05-06 |access-date=2010-05-07 |publisher=Eia.doe.gov}} but have a much lower energy density.
The density of thermal energy contained in the core of a light-water reactor (pressurized water reactor (PWR) or boiling water reactor (BWR)) of typically {{val|1|u=GW}} ({{val|1,000|u=MW}} electrical corresponding to ≈ {{val|3000|u=MW}} thermal) is in the range of 10 to 100 MW of thermal energy per cubic meter of cooling water depending on the location considered in the system (the core itself (≈ {{val|30|u=m3}}), the reactor pressure vessel (≈ {{val|50|u=m3}}), or the whole primary circuit (≈ {{val|300|u=m3}})). This represents a considerable density of energy that requires a continuous water flow at high velocity at all times in order to remove heat from the core, even after an emergency shutdown of the reactor.
The incapacity to cool the cores of three BWRs at Fukushima after the 2011 tsunami and the resulting loss of external electrical power and cold source caused the meltdown of the three cores in only a few hours, even though the three reactors were correctly shut down just after the Tōhoku earthquake. This extremely high power density distinguishes nuclear power plants (NPP's) from any thermal power plants (burning coal, fuel or gas) or any chemical plants and explains the large redundancy required to permanently control the neutron reactivity and to remove the residual heat from the core of NPP's.
= Antimatter–matter annihilation =
Because antimatter–matter interactions result in complete conversion of the rest mass to radiant energy, the energy density of this reaction depends on the density of the matter and antimatter used. A neutron star would approximate the most dense system capable of matter-antimatter annihilation. A black hole, although denser than a neutron star, does not have an equivalent anti-particle form, but would offer the same 100% conversion rate of mass to energy in the form of Hawking radiation. Even in the case of relatively small black holes (smaller than astronomical objects) the power output would be tremendous.
Electric and magnetic fields
{{main|Radiant energy density}}
Electric and magnetic fields can store energy and its density relates to the strength of the fields within a given volume. This (volumetric) energy density is given by
where {{math|E}} is the electric field, {{math|B}} is the magnetic field, and {{mvar|ε}} and {{mvar|µ}} are the permittivity and permeability of the surroundings respectively. The SI unit is the joule per cubic metre.
In ideal (linear and nondispersive) substances, the energy density is
where {{math|D}} is the electric displacement field and {{math|H}} is the magnetizing field. In the case of absence of magnetic fields, by exploiting Fröhlich's relationships it is also possible to extend these equations to anisotropic and nonlinear dielectrics, as well as to calculate the correlated Helmholtz free energy and entropy densities.{{Cite journal |last1=Parravicini |first1=J. |year=2018 |title=Thermodynamic potentials in anisotropic and nonlinear dielectrics |journal=Physica B |volume=541 |pages=54–60 |bibcode=2018PhyB..541...54P |doi=10.1016/j.physb.2018.04.029 |s2cid=125817506}}
In the context of magnetohydrodynamics, the physics of conductive fluids, the magnetic energy density behaves like an additional pressure that adds to the gas pressure of a plasma.
= Pulsed sources =
When a pulsed laser impacts a surface, the radiant exposure, i.e. the energy deposited per unit of surface, may also be called energy density or fluence.{{cite web |title=Terminology |url=https://www.rltvet.com/terminology.html |archive-url=https://web.archive.org/web/20150321233600/http://www.rltvet.com/terminology.html |url-status=usurped |archive-date=March 21, 2015 |website=Regenerative Laser Therapy |language=en}}
Table of material energy densities
{{See also|Energy density Extended Reference Table}}
{{self-contradictory|Too many disparate sources yield apples-to-oranges values. We should explain why TNT is below household waste and metallic zinc|date=April 2019}}
{{unreliable sources|section|date=February 2020}}
The following unit conversions may be helpful when considering the data in the tables: 3.6 MJ = 1 kW⋅h ≈ 1.34 hp⋅h. Since 1 J = 10−6 MJ and 1 m3 = 103 L, divide joule/m3 by 109 to get MJ/L = GJ/m3. Divide MJ/L by 3.6 to get kW⋅h/L.
= Chemical reactions (oxidation) =
{{See also|Energy content of biofuel|Food energy}}
Unless otherwise stated, the values in the following table are lower heating values for perfect combustion, not counting oxidizer mass or volume. When used to produce electricity in a fuel cell or to do work, it is the Gibbs free energy of reaction (ΔG) that sets the theoretical upper limit. If the produced {{H2O}} is vapor, this is generally greater than the lower heat of combustion, whereas if the produced {{chem|H|2|O}} is liquid, it is generally less than the higher heat of combustion. But in the most relevant case of hydrogen, ΔG is 113 MJ/kg if water vapor is produced, and 118 MJ/kg if liquid water is produced, both being less than the lower heat of combustion (120 MJ/kg).CRC Handbook of Chemistry and Physics, 49th Edition, page D-42.
{{Table alignment}}
{{sticky header}}
| class="wikitable sortable sticky-header defaultright col1left col6left"
|+ Energy released by chemical reactions (oxidation) ! Material ! data-sort-type="number" | Specific energy ! data-sort-type="number" | Energy density ! data-sort-type="number" | Specific energy ! data-sort-type="number" | Energy density ! Comment |
| Hydrogen, liquid
| data-sort-value="119.93" | 141.86 (HHV) | data-sort-value="8.491" | 10.044 (HHV) | data-sort-value="33,313.9" | {{val|39,405.6}} (HHV) | data-sort-value="2,358.6" | {{val|2,790.0}} (HHV) |Energy figures apply after reheating to 25 °C.College of the Desert, “Module 1, Hydrogen Properties”, Revision 0, December 2001 [http://energy.gov/sites/prod/files/2014/03/f12/fcm01r0.pdf Hydrogen Properties] {{Webarchive|url=https://web.archive.org/web/20170701144015/https://www.energy.gov/sites/prod/files/2014/03/f12/fcm01r0.pdf |date=2017-07-01 }}. Retrieved 2014-06-08. See note above about use in fuel cells. |
| Hydrogen, gas (681 atm, 69 MPa, 25 °C)
| data-sort-value="119.93" | 141.86 (HHV) | data-sort-value="4.500" | 5.323 (HHV) | data-sort-value="33,313.9" | {{val|39,405.6}} (HHV) | data-sort-value="1,250.0" | {{val|1,478.6}} (HHV) | Data from same reference as for liquid hydrogen. High-pressure tanks weigh much more than the hydrogen they can hold. The hydrogen may be around 5.7% of the total mass,{{cite web|url=http://www.greencarcongress.com/2014/11/20141118-mirai.html|title=Toyota FCV Mirai launches in LA; initial TFCS specs; $57,500 or $499 lease; leaning on Prius analogy|author=Mike Millikin|publisher=Green Car Congress|date=2014-11-18|access-date=2014-11-23|archive-date=2014-11-21|archive-url=https://web.archive.org/web/20141121125909/http://www.greencarcongress.com/2014/11/20141118-mirai.html|url-status=live}} giving just 6.8 MJ per kg total mass for the LHV. See note above about use in fuel cells. |
| Hydrogen, gas ({{cvt|1|atm|kPa|1|lk=in|disp=or}}, 25 °C)
| data-sort-value="119.93" | 141.86 (HHV) | data-sort-value="0.01005" | {{val|0.01188}} (HHV) | data-sort-value="33,313.9" |{{val|39,405.6}} (HHV) | data-sort-value="2.8" | 3.3 (HHV) | |
| Diborane
| 78.2 | 88.4 | {{val|21,722.2}} | data-sort-value="24600" | {{val|24,600.0}} |Greenwood, Norman N.; Earnshaw, Alan (1997), Chemistry of the Elements (2nd ed) (page 164) |
| Beryllium
| 67.6 | 125.1 | {{val|18,777.8}} | {{val|34,750.0}} | |
| Lithium borohydride
| 65.2 | 43.4 | {{val|18,111.1}} | {{val|12,055.6}} | |
| Boron
| 58.9 | 137.8 | {{val|16,361.1}} | {{val|38,277.8}} |{{cite web|title=Boron: A Better Energy Carrier than Hydrogen? (28 February 2009)|url=http://www.eagle.ca/~gcowan/boron_blast.html#TOC|access-date=2010-05-07|publisher=Eagle.ca|archive-date=2007-07-05|archive-url=https://web.archive.org/web/20070705214652/http://www.eagle.ca/~gcowan/boron_blast.html#TOC|url-status=dead}}{{Better source needed|date=August 2023}} |
| Methane (101.3 kPa, 15 °C)
| 55.6 | data-sort-value="0.0378" | {{val|0.0378}} | {{val|15,444.5}} | 10.5 | |
| LNG (NG at −160 °C)
| data-sort-value="53.6" | 53.6 | data-sort-value="22.2" | 22.2 | {{val|14,888.9}} | {{val|6,166.7}} | |
| CNG (NG compressed to 247 atm, 25 MPa ≈ {{val|3600|fmt=commas|u=psi}})
| data-sort-value="53.6" | 53.6 | data-sort-value="9" | 9 | {{val|14,888.9}} | {{val|2,500.0}} | |
| Natural gas
| data-sort-value="53.6" | 53.6Envestra Limited. [http://www.natural-gas.com.au/about/references.html Natural Gas] {{webarchive|url=https://web.archive.org/web/20081010202138/http://www.natural-gas.com.au/about/references.html |date=2008-10-10 }}. Retrieved 2008-10-05. | data-sort-value="0.0364" | {{val|0.0364}} | {{val|14,888.9}} | 10.1 | |
| LPG propane
| 49.6 | data-sort-value="25.3" | 25.3 | {{val|13,777.8}} | {{val|7,027.8}} |
| LPG butane
| 49.1 | data-sort-value="27.7" | 27.7 | {{val|13,638.9}} | {{val|7,694.5}} |
| Petrol (Gasoline)
| 46.4 | data-sort-value="34.2" | 34.2 | {{val|12,888.9}} | {{val|9,500.0}} |
| Polypropylene plastic
| data-sort-value="46.4" | 46.4 | 41.7 | {{val|12,888.9}} | {{val|11,583.3}} | |
| Polyethylene plastic
| 42.6 | {{val|12,861.1}} | {{val|11,833.3}} | |
| Residential heating oil
| 46.2 | data-sort-value="37.3" | 37.3 | {{val|12,833.3}} | {{val|10,361.1}} |
| Diesel fuel
| 45.6 | data-sort-value="38.6" | 38.6 | {{val|12,666.7}} | {{val|10,722.2}} |
| 100LL Avgas
| 31.59 | {{val|12,222.2}} | {{val|8,775.0}} | |
| Jet fuel (e.g. kerosene)
| data-sort-value="42.8" | 43{{cite web | url=https://hypertextbook.com/facts/2003/EvelynGofman.shtml | title=Energy density of aviation fuel | first=Evelyn | last=Gofman | year=2003 | website=The Physics Factbook | editor-last=Elert | editor-first=Glenn | access-date=2019-07-28 |title=Handbook of Products |publisher=Air BP |url=http://www.bp.com/liveassets/bp_internet/aviation/air_bp/STAGING/local_assets/downloads_pdfs/a/air_bp_products_handbook_04004_1.pdf |url-status=dead |archive-url=https://web.archive.org/web/20110608075828/http://www.bp.com/liveassets/bp_internet/aviation/air_bp/STAGING/local_assets/downloads_pdfs/a/air_bp_products_handbook_04004_1.pdf |archive-date=2011-06-08 |pages=11–13 }} | 35 | {{val|11,944.4}} | {{val|9,722.2}} | aircraft engine |
| Gasohol E10 (10% ethanol 90% gasoline by volume)
| 43.54 | data-sort-value="33.18" | 33.18 | {{val|12,094.5}} | {{val|9,216.7}} | |
| Lithium
| 43.1 | 23.0 | {{val|11,972.2}} | {{val|6,388.9}} | |
| Biodiesel oil (vegetable oil)
| 42.20 | data-sort-value="33" | 33 | 11,722.2 | 9,166.7 | |
| DMF (2,5-dimethylfuran)
| data-sort-value="42" | 42{{cite journal|last1=Román-Leshkov|first1=Yuriy|last2=Barrett|first2=Christopher J.|last3=Liu|first3=Zhen Y.|last4=Dumesic|first4=James A.|title=Production of dimethylfuran for liquid fuels from biomass-derived carbohydrates|journal=Nature|date=21 June 2007|volume=447|issue=7147|pages=982–985|doi=10.1038/nature05923|pmid=17581580|bibcode=2007Natur.447..982R|s2cid=4366510}} | 37.8 | 11,666.7 | 10,500.0 |{{Clarify|date=February 2009|need a quote from the cite containing "42" and "37.8" or equivalent in W⋅h/kg and W⋅h/L}} |
| Paraffin wax
| data-sort-value="37.8" | 37.8 | data-sort-value="11700" | {{val|11,700}} | data-sort-value="10500" | {{val|10,500}} | |
| Crude oil (tonne of oil equivalent)
| 41.868 | {{val|11,630}} | {{val|10,278}} | |
| Polystyrene plastic
| data-sort-value="41.4" | 41.4 | 43.5 | {{val|11,500.0}} | {{val|12,083.3}} | |
| Body fat
| 38 | data-sort-value="35" | 35 | {{val|10,555.6}} | {{val|9,722.2}} |metabolism in human body (22% efficiency{{cite web|url=http://www.ebikes.ca/documents/Ebike_Energy.pdf|title=The Energy Cost of Electric and Human-Powered Bicycles|author=Justin Lemire-Elmore|date=2004-04-13|page=5|access-date=2009-02-26|quote=properly trained athlete will have efficiencies of 22 to 26%|archive-date=2014-06-28|archive-url=https://web.archive.org/web/20140628130535/http://www.ebikes.ca/documents/Ebike_Energy.pdf|url-status=live}}) |
| Butanol
| 36.6 | 29.2 | {{val|10,166.7}} | {{val|8,111.1}} | |
| Gasohol E85 (85% ethanol 15% gasoline by volume)
| 33.1 | data-sort-value="25.65" | 25.65{{Citation needed|date=October 2014}} | {{val|9,194.5}} | {{val|7,125.0}} | |
| Graphite
| 32.7 | 72.9 | {{val|9,083.3}} | {{val|20,250.0}} | |
| Coal, anthracite
| data-sort-value="26" | 26–33 | data-sort-value="34" | 34–43 | data-sort-value="7222.2" | {{val|7,222.2}}–{{val|9,166.7}} | data-sort-value="9444.5" | {{val|9,444.5}}–{{val|11,944.5}} |Figures represent perfect combustion not counting oxidizer, but efficiency of conversion to electricity is ≈36% |
| Silicon
| 32.6 | 75.9 | data-sort-value="9056" | 9,056 | data-sort-value="21080" | 21,080 |
| Aluminium
| 31.0 | 83.8 | {{val|8,611.1}} | {{val|23,277.8}} | |
| Ethanol
| 30 | 24 | {{val|8,333.3}} | {{val|6,666.7}} | |
| DME
| data-sort-value="28.4" | 31.7 (HHV) | data-sort-value="19.03" | 21.24 (HHV) | data-sort-value="7,888.9" | {{val|8,805.6}} (HHV) | data-sort-value="5,286.1" | {{val|5,900.0}} (HHV) |{{cite web|last=Bossel|first=Ulf|date=July 2003|title=The Physics of the Hydrogen Economy|url=https://www.efcf.com/reports/E05.pdf|url-status=dead|archive-url=https://web.archive.org/web/20060319173951/https://www.efcf.com/reports/E05.pdf|archive-date=2006-03-19|access-date=2019-04-06|publisher=European Fuel Cell News|quote=The Higher Heating Values are 22.7, 29.7 or 31.7 MJ/kg for methanol, ethanol and DME, respectively, while gasoline contains about 45 MJ per kg.}}{{cite web|date=2013-11-18|title=Dimethyl Ether (DME)|url=http://www.etipbioenergy.eu/images/dme-fact-sheet.pdf|access-date=2019-04-06|website=European Biofuels Technology Platform|archive-date=2019-07-13|archive-url=https://web.archive.org/web/20190713132837/http://www.etipbioenergy.eu/images/dme-fact-sheet.pdf|url-status=dead}} DME density and lower heating value were obtained from the table on the first page. |
| Polyester plastic
| data-sort-value="26.0" | 26.0 | 35.6 | {{val|7,222.2}} | {{val|9,888.9}} | |
| Magnesium
| 24.7 | 43.0 | {{val|6,861.1}} | 11,944.5 | |
| Phosphorus (white)
| data-sort-value="24.30" | 24.30 | data-sort-value="44.30" | 44.30 | data-sort-value="6750" | {{val|6,750}} | data-sort-value="12310" | {{val|12,310}} |
| Coal, bituminous
| data-sort-value="24" | 24–35 | data-sort-value="26" | 26–49 | data-sort-value="6666.7" | {{val|6,666.7}}–{{val|9,722.2}} | data-sort-value="7222.2" | {{val|7,222.2}}–{{val|13,611.1}} |
| PET plastic (impure)
| data-sort-value="32.4" | < ~32.4 | {{val|6,527.8}} | data-sort-value="9000" | < ~{{val|9000}} | |
| Methanol
| 19.7 | 15.6 | {{val|5,472.2}} | {{val|4,333.3}} | |
| Titanium
| data-sort-value="19.74" | 19.74 | data-sort-value="88.93" | 88.93 | data-sort-value="5480" | {{val|5,480}} | data-sort-value="24700" | {{val|24,700}} | burned to titanium dioxide |
| Hydrazine
| 19.5 | 19.3 | {{val|5,416.7}} | {{val|5,361.1}} |
| Liquid ammonia
| 18.6 | 11.5 | {{val|5,166.7}} | {{val|3,194.5}} | burned to nitrogen and water |
| Potassium
| 18.6 | 16.5 | {{val|5,160}} | {{val|4,600}} | burned to dry potassium oxide |
| PVC plastic (improper combustion toxic)
| data-sort-value="18.0" | 18.0 | 25.2 | {{val|5,000.0}} | {{val|7,000.0}} | {{Clarify|date=October 2008}} |
| Wood
| 18.0 | | {{val|5,000.0}} | |
| Peat briquette
| 17.7 | | {{val|4,916.7}} | |
| Sugars, carbohydrates, and protein
| 17 | data-sort-value="26.2" | 26.2 (dextrose) | {{val|4,722.2}} | {{val|7,277.8}} |metabolism in human body (22% efficiency{{cite web|url=http://www.ebikes.ca/documents/Ebike_Energy.pdf|title=The Energy Cost of Electric and Human-Powered Bicycle|author=Justin Lemire-elmore|date=April 13, 2004|access-date=2012-01-25|archive-date=2014-06-28|archive-url=https://web.archive.org/web/20140628130535/http://www.ebikes.ca/documents/Ebike_Energy.pdf|url-status=live}}){{Citation needed|date=February 2009|reason=Justin Lemire-Elmore PDF does not specify type of food nor fatty acids nor dextrose, so specific cite needed with page number and precise quotes}} |
| Calcium
| 15.9 | 24.6 | {{val|4,416.7}} | {{val|6,833.3}} |{{Citation needed|date=November 2008}} |
| Glucose
| 15.55 | 23.9 | {{val|4,319.5}} | {{val|6,638.9}} | |
| Dry cow dung and camel dung
| data-sort-value="15.5" | 15.5{{cite web|url=http://www.davdata.nl/math/energy.html |title=energy buffers |publisher=Home.hccnet.nl |access-date=2010-05-07}} | | {{val|4,305.6}} | | |
| Coal, lignite
| data-sort-value="10" | 10–20 | | {{val|2,777.8}}–{{val|5,555.6}} | |{{Citation needed|date=November 2008}} |
| Sodium
| 13.3 | 12.8 | {{val|3,694.5}} | {{val|3,555.6}} |burned to wet sodium hydroxide |
| Peat
| 12.8 | | 3,555.6 | | |
| Nitromethane
| 11.3 | 12.85 | {{val|3,138.9}} | {{val|3,570}} | |
| Manganese
| 9.46 | 68.2 | {{val|2,630}} | {{val|18,900}} | burned to manganese dioxide |
| Sulfur
| 9.23 | 19.11 | {{val|2,563.9}} | {{val|5,308.3}} | burned to sulfur dioxideAnne Wignall and Terry Wales. [http://www.wignallandwales.co.nz/Chem-12-WB/Sample-chapter.pdf Chemistry 12 Workbook, page 138] {{webarchive|url=https://web.archive.org/web/20110913164216/http://www.wignallandwales.co.nz/Chem-12-WB/Sample-chapter.pdf|date=2011-09-13}}. Pearson Education NZ {{ISBN|978-0-582-54974-6}} |
| Sodium
| 9.1 | 8.8 | {{val|2,527.8}} | {{val|2,444.5}} | burned to dry sodium oxide |
| Household waste
| data-sort-value="8.0" | 8.0David E. Dirkse. [http://www.davdata.nl/math/energy.html energy buffers]. "household waste 8..11 MJ/kg" | | {{val|2,222.2}} | | |
| Iron
| 7.4 | 57.7 | {{val|2,052.9}} | {{val|16,004.1}} | burned to iron(III) oxideThomas C. Allison. (2013). NIST-JANAF Thermochemical Tables - SRD 13 (1.0.2) [dataset]. National Institute of Standards and Technology. |
| Iron
| 6.7 | 52.2 | {{val|1,858.3}} | {{val|14,487.2}} | burned to Iron(II,III) oxide |
| Zinc
| 5.3 | 38.0 | {{val|1,472.2}} | {{val|10,555.6}} | |
| Teflon plastic
| 5.1 | 11.2 | {{val|1,416.7}} | {{val|3,111.1}} |combustion toxic, but flame retardant |
| Iron
| 4.9 | 38.2 | {{val|1,361.1}} | {{val|10,611.1}} | burned to iron(II) oxide |
| Gunpowder
| data-sort-value="8" | 4.7–11.3{{cite book|last1=Lu|first1=Gui-e|last2=Chang|first2=Wen-ping|last3=Jiang|first3=Jin-yong|last4=Du|first4=Shi-guo|title=2011 International Conference on Materials for Renewable Energy & Environment |chapter=Study on the energy density of gunpowder heat source |pages=1185–1187|date=May 2011|doi=10.1109/ICMREE.2011.5930549|publisher=IEEE|isbn=978-1-61284-749-8|s2cid=36130191}} | data-sort-value="9.4" | 5.9–12.9 | | data-sort-value="2600" | {{val|1,600}}–{{val|3,580}} | |
| TNT
| 4.184 | 6.92 | data-sort-value="1162" | {{val|1,162}} | data-sort-value="1920" | {{val|1,920}} | |
| Barium
| 3.99 | 14.0 | data-sort-value="1110" | {{val|1,110}} | data-sort-value="3890" | {{val|3,890}} | burned to barium dioxide |
| ANFO
| 3.7 | | {{val|1,027.8}} | | |
= Electrochemical reactions (batteries) =
{{Table alignment}}
== Common battery formats ==
| class="wikitable sortable sticky-header" style="text-align: center;"
|+ Battery energy capacities |
| Storage device
! data-sort-type="number" | Energy content ! Energy content ! data-sort-type="number" | Typical ! Typical dimensions ! data-sort-type="number" | Typical volume (mL) ! data-sort-type="number" | Specific energy (MJ/kg) ! data-sort-type="number" | Energy density (MJ/L) |
|---|
| style="text-align:left;" |Alkaline AA battery{{cite web|url=http://www.allaboutbatteries.com/Energy-tables.html|title=Battery Energy Tables|archive-url=https://web.archive.org/web/20111204090808/http://www.allaboutbatteries.com/Energy-tables.html|archive-date=2011-12-04|url-status=dead}}
| data-sort-value="9360" | {{val|9,360}} |2.6 | 24 | 14.2 × 50 | 7.92 | 0.39 | 1.18 |
| style="text-align:left;" |Alkaline C battery
| data-sort-value="34416" | {{val|34,416}} |9.5 | 65 | 26 × 46 | 24.42 | 0.53 | 1.41 |
| style="text-align:left;" |NiMH AA battery
| data-sort-value="9072" | {{val|9,072}} | 2.5 | 26 | 14.2 × 50 | 7.92 | 0.35 | 1.15 |
| style="text-align:left;" |NiMH C battery
| data-sort-value="19440" | {{val|19,440}} | 5.4 | 82 | 26 × 46 | 24.42 | 0.24 | 0.80 |
| style="text-align:left;" |Lithium-ion 18650 battery
| data-sort-value="28800" | {{val|28,800}}–{{val|46,800}} | 8–13 | data-sort-value="44" | 44–49{{cite web|url=http://www.best18650battery.com/|title=18650 Battery capacities|access-date=2017-01-26|archive-date=2016-11-27|archive-url=https://web.archive.org/web/20161127234556/http://best18650battery.com/|url-status=live}} | 18 × 65 | 16.54 | 0.59–1.06 | 1.74–2.83 |
= Nuclear reactions =
{{Table alignment}}
| class="wikitable sortable sticky-header defaultright col1left col6left"
|+ Energy released by nuclear reactions ! Material ! data-sort-type="number" | Specific energy ! data-sort-type="number" | Energy density ! data-sort-type="number" | Specific energy ! data-sort-type="number" | Energy density ! Comment |
| Antimatter
| {{val|89,875,517,874}} ≈ {{val|90|u=PJ/kg}} | Depends on the density of the antimatter's form | {{val|24,965,421,631,578}} ≈ 25 TW⋅h/kg | Depends on the density of the antimatter's form | Annihilation, counting both the consumed antimatter mass and ordinary matter mass |
| Hydrogen (fusion)
| data-sort-value="639,780,320" | {{val|639,780,320}}Calculated from fractional mass loss times c squared. but at least 2% of this is lost to neutrinos. | Depends on conditions | data-sort-value="177,716,755,600" | {{val|177,716,755,600}} | Depends on conditions | Reaction 4H→4He |
| Deuterium (fusion) | data-sort-value="571,182,758" | 571,182,758Calculated from fractional mass loss times c squared. {{cite journal|title=Maximizing specific energy by breeding deuterium|first=Justin |last=Ball|journal=Nuclear Fusion|year=2019|volume=59|issue=10 |pages=106043|doi=10.1088/1741-4326/ab394c|arxiv=1908.00834 |bibcode=2019NucFu..59j6043B |s2cid=199405246 }} | Depends on conditions | data-sort-value="158,661,876,600" | {{val|158,661,876,600}} | Depends on conditions |Proposed fusion scheme for D+D→4He, by combining D+D→T+H, T+D→4He+n, n+H→D and D+D→3He+n, 3He+D→4He+H, n+H→D |
| Deuterium+tritium (fusion)
| data-sort-value="337,387,388"| {{val|337,387,388}} | Depends on conditions | data-sort-value="93,718,718,800"| {{val|93,718,718,800}} | Depends on conditions | D + T → 4He + n |
| Lithium-6 deuteride (fusion)
| data-sort-value="268,848,415" | {{val|268,848,415}} | Depends on conditions | data-sort-value="74,680,115,100" | {{val|74,680,115,100}} | Depends on conditions | {{sup|6}}LiD → 24He |
| Plutonium-239
| {{val|83,610,000}} | data-sort-value="1660494600" | {{val|1,300,000,000}}–{{va|1,700,000,000}} (depends on crystallographic phase) | {{val|23,222,915,000}} | data-sort-value="461248500000" | {{val|370,000,000,000}}–{{val|460,000,000,000}} (depends on crystallographic phase) |Heat produced in Fission reactor |
| Plutonium-239
| 31,000,000 | data-sort-value="615660000" | {{val|490,000,000}}–{{val|620,000,000}} (Depends on crystallographic phase) | {{val|8,700,000,000}} | data-sort-value="171016670000" | {{val|140,000,000,000}}–{{val|170,000,000,000}} (depends on crystallographic phase) | Electricity produced in Fission reactor |
| Uranium
| data-sort-value="80,620,000" | {{val|80,620,000}} | data-sort-value="1,539,842,000" | {{val|1,539,842,000}} | {{val|22,394,000,000}} | | Heat produced in breeder reactor |
| Thorium
| data-sort-value="79,420,000" | {{val|79,420,000}}{{cite web |url=http://www.whatisnuclear.com/physics/energy_density_of_nuclear.html |title=Computing the energy density of nuclear fuel |publisher=whatisnuclear.com |access-date=2014-04-17 |archive-date=2017-01-04 |archive-url=https://web.archive.org/web/20170104235210/http://www.whatisnuclear.com/physics/energy_density_of_nuclear.html |url-status=live }} | data-sort-value="929,214,000" | {{val|929,214,000}} | {{val|22,061,000,000}} | | Heat produced in breeder reactor (experimental) |
| Plutonium-238
| {{val|2,239,000}} | {{val|43,277,631}} | {{val|621,900,000}} | | Radioisotope thermoelectric generator. The heat is only produced at a rate of 0.57 W/g. |
= In material deformation =
The mechanical energy storage capacity, or resilience, of a Hookean material when it is deformed to the point of failure can be computed by calculating tensile strength times the maximum elongation dividing by two. The maximum elongation of a Hookean material can be computed by dividing stiffness of that material by its ultimate tensile strength. The following table lists these values computed using the Young's modulus as measure of stiffness:
| class="wikitable sortable sticky-header"
|+ Mechanical energy capacities ! Material ! Energy density by mass (J/kg) ! Resilience: Energy density by volume (J/L) ! Density (kg/L) (GPa) ! Tensile yield strength (MPa) |
| Rubber band
| | |
| Steel, ASTM A228 (yield, 1 mm diameter)
| {{val|1,440}}–{{val|1,770}} | {{val|11,200}}–{{val|13,800}} |
| Acetals
| 908 | 754 |access-date=2019-12-12}} |
| Nylon-6
| 233–1,870 | 253–2,030 | 1.084 |
| Copper Beryllium 25-1/2 HT (yield)
| 684 |
| Polycarbonates
| 433–615 | 520–740 |
| ABS plastics
| 241–534 | 258–571 | 1.07 |
| Acrylic
| | {{val|1,530}} | |
| Aluminium 7077-T8 (yield)
| 399 |
| Steel, stainless, 301-H (yield)
| 301 | 8.0{{cite web | url=https://hypertextbook.com/facts/2004/KarenSutherland.shtml | title=Density of steel | first1=Karen | last1=Sutherland | year=2004 | first2=Monica | last2=Martin | website=The Physics Factbook | editor-last=Elert | editor-first=Glenn | access-date=2020-06-18 | archive-date=2019-11-02 | archive-url=https://web.archive.org/web/20191102195434/https://hypertextbook.com/facts/2004/KarenSutherland.shtml | url-status=live }} |
| Aluminium 6061-T6 (yield @ 24 °C)
| 205 | 553 |
| Epoxy resins
| | 113–{{val|1,810}} | |
| Douglas fir Wood
| 158–200 | 96 |
| Steel, Mild AISI 1018
| 42.4 | 334 |
| Aluminium (not alloyed)
| 32.5 | 87.7 |
| Pine (American Eastern White, flexural)
| 31.8–32.8 | 11.1–11.5 |
| Brass
| 28.6–36.5 | 250–306 |
| Copper
| 23.1 | 207 |
| Glass
| 5.56–10.0 | 13.9–25.0 |
= Other release mechanisms =
{{Table alignment}}
See also
{{Portal|Energy}}
{{div col|colwidth=22em}}
- Energy content of biofuel
- Energy density Extended Reference Table
- Figure of merit
- Food energy
- Heat of combustion
- High-energy-density matter
- Power density and specifically Power-to-weight ratio
- Rechargeable battery
- Solid-state battery
- Specific energy
- Specific impulse
- Orders of magnitude (energy)
{{div col end}}
References
{{reflist|30em|refs=
- {{Cite journal |doi = 10.1039/C5EE01659B|title = Nanotechnology enabled rechargeable Li–SO2 batteries: Another approach towards post-lithium-ion battery systems|year = 2015|last1 = Jeong|first1 = Goojin|last2 = Kim|first2 = Hansu|last3 = Park|first3 = Jong Hwan|last4 = Jeon|first4 = Jaehwan|last5 = Jin|first5 = Xing|last6 = Song|first6 = Juhye|last7 = Kim|first7 = Bo-Ram|last8 = Park|first8 = Min-Sik|last9 = Kim|first9 = Ji Man|last10 = Kim|first10 = Young-Jun|journal = Energy & Environmental Science|volume = 8|issue = 11|pages = 3173–3180}}
- "Panasonic Develops New Higher-Capacity 18650 Li-Ion Cells". Green Car Congress. N.p., 25 Dec. 2009. Web.
- {{Cite journal |doi = 10.1016/j.aca.2005.11.025|pmid = 17761246|title = New nanomaterials for light weight lithium batteries|year = 2006|last1 = Stura|first1 = Enrico|last2 = Nicolini|first2 = Claudio|journal = Analytica Chimica Acta|volume = 568|issue = 1–2|pages = 57–64| bibcode=2006AcAC..568...57S }}
- "Heat Values of Various Fuels – World Nuclear Association". World Nuclear Association. N.p., Sept. 2016. Web.
- "Overview of Storage Development DOE Hydrogen Program". Office of Energy Efficiency & Renewable Energy. N.p., May 2000. Web.
- {{Cite journal | doi=10.1115/1.4034860| title=Nanotechnology in Batteries| year=2017| last1=Wong| first1=Kaufui| last2=Dia| first2=Sarah| journal=Journal of Energy Resources Technology| volume=139}}}}
Further reading
- 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
- {{note|att}} "Aircraft Fuels". Energy, Technology and the Environment Ed. Attilio Bisio. Vol. 1. New York: John Wiley and Sons, Inc., 1995. 257–259
- "[http://www1.eere.energy.gov/vehiclesandfuels/pdfs/deer_2002/session1/2002_deer_eberhardt.pdf Fuels of the Future for Cars and Trucks]" – 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
- {{cite web|url=http://www.world-nuclear.org/information-library/facts-and-figures/heat-values-of-various-fuels.aspx|title=Heat values of various fuels – World Nuclear Association|work=www.world-nuclear.org|access-date=4 November 2018}}
{{Authority control}}
{{DEFAULTSORT:Energy Density}}
Category:Volume-specific quantities