TheInfoList

The heating value (or energy value or calorific value) of a
substance Substance may refer to: * Substance (Jainism), a term in Jain ontology to denote the base or owner of attributes * Chemical substance, a material with a definite chemical composition * Matter, anything that has mass and takes up space * Substance th ...
, usually a
fuel A fuel is any material that can be made to react with other substances so that it releases energy as thermal energy Thermal radiation in visible light can be seen on this hot metalwork. Thermal energy refers to several distinct physical con ...

or
food Food is any substance consumed to provide Nutrient, nutritional support for an organism. Food is usually of plant, animal or Fungus, fungal origin, and contains essential nutrients, such as carbohydrates, fats, protein (nutrient), proteins, vi ...

(see
food energy Food energy is chemical energy Chemical energy is the energy of chemical substance A chemical substance is a form of matter In classical physics and general chemistry, matter is any substance that has mass and takes up space by havin ...
), is the amount of
heat In thermodynamics Thermodynamics is a branch of physics that deals with heat, Work (thermodynamics), work, and temperature, and their relation to energy, entropy, and the physical properties of matter and radiation. The behavior of these ...

released during the combustion of a specified amount of it. The ''calorific value'' is the total
energy In physics Physics is the that studies , its , its and behavior through , and the related entities of and . "Physical science is that department of knowledge which relates to the order of nature, or, in other words, to the regula ...

released as
heat In thermodynamics Thermodynamics is a branch of physics that deals with heat, Work (thermodynamics), work, and temperature, and their relation to energy, entropy, and the physical properties of matter and radiation. The behavior of these ...

when a substance undergoes complete
combustion Combustion, or burning, is a high-temperature exothermic redox chemical reaction between a fuel (the reductant) and an oxidant, usually atmospheric oxygen, that produces oxidized, often gaseous products, in a mixture termed as smoke. Combustion ...
with
oxygen Oxygen is the chemical element Image:Simple Periodic Table Chart-blocks.svg, 400px, Periodic table, The periodic table of the chemical elements In chemistry, an element is a pure substance consisting only of atoms that all have the same ...

under
standard conditions Standard temperature and pressure (STP) are standard Standard may refer to: Flags * Colours, standards and guidons * Standard (flag), a type of flag used for personal identification Norm, convention or requirement * Standard (metrology), a ...
. The chemical reaction is typically a
hydrocarbon In organic chemistry Organic chemistry is a branch of chemistry Chemistry is the study of the properties and behavior of . It is a that covers the that make up matter to the composed of s, s and s: their composition, structure, prop ...
or other organic molecule reacting with oxygen to form
carbon dioxide Carbon dioxide (chemical formula A chemical formula is a way of presenting information about the chemical proportions of s that constitute a particular or molecule, using symbols, numbers, and sometimes also other symbols, such as pare ...

and
water Water (chemical formula H2O) is an Inorganic compound, inorganic, transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known li ...

and release heat. It may be expressed with the quantities: * energy/
mole Mole (or Molé) may refer to: Animals * Mole (animal) or "true mole", mammals in the family Talpidae, found in Eurasia and North America * Golden moles, southern African mammals in the family Chrysochloridae, similar to but unrelated to Talpidae ...
of fuel * energy/mass of fuel * energy/volume of the fuel There are two kinds of enthalpy of combustion, called higher and lower heating value, depending on how much the products are allowed to cool and whether compounds like are allowed to condense. The high heat values are conventionally measured with a
bomb calorimeter A calorimeter is an object used for calorimetry upSnellen direct calorimetry chamber, University of Ottawa. Calorimetry is the science or act of measuring changes in ''state variables'' of a body for the purpose of deriving the heat transf ...
. Low heat values are calculated from high heat value test data. They may also be calculated as the difference between the
heat of formationThe standard enthalpy of formation or standard heat of formation of a compound is the change of enthalpy Enthalpy is a property of a thermodynamic system A thermodynamic system is a body of matter and/or radiation, confined in space by walls, wi ...
Δ''H'' of the products and reactants (though this approach is somewhat artificial since most heats of formation are typically calculated from measured heats of combustion). For a fuel of composition C''c''H''h''O''o''N''n'', the (higher) heat of combustion is usually to a good approximation (±3%), though it can be significantly off if (for instance in the case of
nitroglycerine Nitroglycerin (NG), also known as trinitroglycerin (TNG), nitro, glyceryl trinitrate (GTN), or 1,2,3-trinitroxypropane, is a dense, colorless, oily, explosive An explosive (or explosive material) is a reactive substance that contains a great ...
, , this formula would predict a heat of combustion of 0). The value corresponds to an
exothermic In thermodynamics Thermodynamics is a branch of physics that deals with heat, Work (thermodynamics), work, and temperature, and their relation to energy, entropy, and the physical properties of matter and radiation. The behavior of these qu ...

reaction (a negative change in
enthalpy Enthalpy , a property of a thermodynamic system, is the sum of the system's internal energy and the product of its pressure and volume. It is a state function used in many measurements in chemical, biological, and physical systems at a constant p ...

) because the double
bond Bond or bonds may refer to: Common meanings * Bond (finance) In finance Finance is the study of financial institutions, financial markets and how they operate within the financial system. It is concerned with the creation and management of ...
in molecular oxygen is much weaker than other double bonds or pairs of single bonds, particularly those in the combustion products carbon dioxide and water; conversion of the weak bonds in
oxygen Oxygen is the chemical element Image:Simple Periodic Table Chart-blocks.svg, 400px, Periodic table, The periodic table of the chemical elements In chemistry, an element is a pure substance consisting only of atoms that all have the same ...

to the stronger bonds in
carbon dioxide Carbon dioxide (chemical formula A chemical formula is a way of presenting information about the chemical proportions of s that constitute a particular or molecule, using symbols, numbers, and sometimes also other symbols, such as pare ...

and
water Water (chemical formula H2O) is an Inorganic compound, inorganic, transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known li ...

releases energy as heat. By convention, the (higher) heat of combustion is defined to be the heat released for the complete combustion of a compound in its standard state to form stable products in their standard states: hydrogen is converted to water (in its liquid state), carbon is converted to carbon dioxide gas, and nitrogen is converted to nitrogen gas. That is, the heat of combustion, Δ''H''°comb, is the heat of reaction of the following process: : (std.) + (g, xs.) → ''c'' (g) + (l) + (g) Chlorine and sulfur are not quite standardized; they are usually assumed to convert to hydrogen chloride gas and or gas, respectively, or to dilute aqueous hydrochloric and sulfuric acids, respectively, when the combustion is conducted in a bomb containing some quantity of water.

# Ways of determination

## Gross and net

Zwolinski and Wilhoit defined, in 1972, "gross" and "net" values for heats of combustion. In the gross definition the products are the most stable compounds e.g. (l), (l), (s) and (l). In the net definition the products are those produced when the compound is burned in an open flame e.g. (g) (g) (g) and (g). In both definitions the products for C, F, Cl and N are (g) (g) (g) and (g) respectively. Dulong's Formula The heating value of a fuel can be calculated with the results of ultimate analysis of fuel. From analysis, percentages of the combustibles in the fuel (
Carbon Carbon (from la, carbo "coal") is a with the C and 6. It is lic and —making four s available to form s. It belongs to group 14 of the periodic table. Carbon makes up only about 0.025 percent of Earth's crust. Three occur naturally, ...

,
Hydrogen Hydrogen is the chemical element with the Symbol (chemistry), symbol H and atomic number 1. Hydrogen is the lightest element. At standard temperature and pressure, standard conditions hydrogen is a gas of diatomic molecules having the che ...

,
Sulphur Sulfur (in nontechnical British English: sulphur) is a chemical element Image:Simple Periodic Table Chart-blocks.svg, 400px, Periodic table, The periodic table of the chemical elements In chemistry, an element is a pure substance consis ...

) are known. Since the heat of combustion of these elements is known, the heating value can be calculated using Dulong's Formula. LHV J/g 33.87mC + 122.3(mH - mO ÷ 8) + 9.4mS mC, mH, mO, mN, and mS: contents of carbon, hydrogen, oxygen, nitrogen, and sulfur on any (wet, dry or ash free) basis, respectively.

## Higher heating value

The higher heating value (HHV; ''gross energy'', ''upper heating value'', ''gross calorific value'' ''GCV'', or ''higher calorific value''; ''HCV'') indicates the upper limit of the available thermal energy produced by a complete combustion of fuel. It is measured as a unit of energy per unit mass or volume of substance. The HHV is determined by bringing all the products of combustion back to the original pre-combustion temperature, and in particular condensing any vapor produced. Such measurements often use a standard temperature of . This is the same as the thermodynamic heat of combustion since the
enthalpy Enthalpy , a property of a thermodynamic system, is the sum of the system's internal energy and the product of its pressure and volume. It is a state function used in many measurements in chemical, biological, and physical systems at a constant p ...

change for the reaction assumes a common temperature of the compounds before and after combustion, in which case the water produced by combustion is condensed to a liquid. The higher heating value takes into account the
latent heat of vaporization The enthalpy of vaporization (symbol ), also known as the (latent) heat of vaporization or heat of evaporation, is the amount of energy (enthalpy Enthalpy is a property of a thermodynamic system A thermodynamic system is a body of matter a ...
of
water Water (chemical formula H2O) is an Inorganic compound, inorganic, transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known li ...

in the combustion products, and is useful in calculating heating values for fuels where
condensation Condensation is the change of the state of matter In physics, a state of matter is one of the distinct forms in which matter can exist. Four states of matter are observable in everyday life: solid, liquid, gas, and Plasma (physics), plasma. ...

of the reaction products is practical (e.g., in a gas-fired
boiler Poland Poland ( pl, Polska ), officially the Republic of Poland ( pl, Rzeczpospolita Polska, links=no ), is a country located in Central Europe. It is divided into 16 Voivodeships of Poland, administrative provinces, covering an area of , ...

used for space heat). In other words, HHV assumes all the water component is in liquid state at the end of combustion (in product of combustion) and that heat delivered at temperatures below can be put to use.

## Lower heating value

The lower heating value (LHV; ''net calorific value''; ''NCV'', or ''lower calorific value''; ''LCV'') is another measure of available thermal energy produced by a combustion of fuel, measured as a unit of energy per unit mass or volume of substance. In contrast to the HHV, the LHV considers energy losses such as the energy used to vaporize water - although its exact definition is not uniformly agreed upon. One definition is simply to subtract the
heat of vaporization The enthalpy of vaporization (symbol ), also known as the (latent) heat of vaporization or heat of evaporation, is the amount of energy (enthalpy Enthalpy , a property of a thermodynamic system, is the sum of the system's internal energy and ...
of the water from the higher heating value. This treats any H2O formed as a vapor. The energy required to vaporize the water therefore is not released as heat. LHV calculations assume that the water component of a combustion process is in vapor state at the end of combustion, as opposed to the
higher heating value The heating value (or energy value or calorific value) of a substance Substance may refer to: * Substance (Jainism), a term in Jain ontology to denote the base or owner of attributes * Chemical substance, a material with a definite chemical composi ...
(HHV) (a.k.a. ''gross calorific value'' or ''gross CV'') which assumes that all of the water in a combustion process is in a liquid state after a combustion process. Another definition of the LHV is the amount of heat released when the products are cooled to . This means that the
latent heat of vaporization The enthalpy of vaporization (symbol ), also known as the (latent) heat of vaporization or heat of evaporation, is the amount of energy (enthalpy Enthalpy is a property of a thermodynamic system A thermodynamic system is a body of matter a ...
of
water Water (chemical formula H2O) is an Inorganic compound, inorganic, transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known li ...

and other reaction products is not recovered. It is useful in comparing fuels where condensation of the combustion products is impractical, or heat at a temperature below cannot be put to use. One definition of lower heating value, adopted by the
American Petroleum Institute The American Petroleum Institute (API) is the largest U.S. trade association A trade association, also known as an industry trade group, business association, sector association or industry body, is an organization founded and funded by business ...
(API), uses a reference temperature of . Another definition, used by Gas Processors Suppliers Association (GPSA) and originally used by API (data collected for API research project 44), is the
enthalpy Enthalpy , a property of a thermodynamic system, is the sum of the system's internal energy and the product of its pressure and volume. It is a state function used in many measurements in chemical, biological, and physical systems at a constant p ...

of all combustion products minus the enthalpy of the fuel at the reference temperature (API research project 44 used 25 °C. GPSA currently uses 60 °F), minus the enthalpy of the
stoichiometric Stoichiometry is the calculation of reactants and products in chemical reaction A chemical reaction is a process that leads to the chemical transformation of one set of chemical substances to another. Classically, chemical A chemical s ...
oxygen Oxygen is the chemical element Image:Simple Periodic Table Chart-blocks.svg, 400px, Periodic table, The periodic table of the chemical elements In chemistry, an element is a pure substance consisting only of atoms that all have the same ...

(O2) at the reference temperature, minus the heat of vaporization of the vapor content of the combustion products. The definition in which the combustion products are all returned to the reference temperature is more easily calculated from the higher heating value than when using other definitions and will in fact give a slightly different answer.

## Gross heating value

Gross heating value accounts for water in the exhaust leaving as vapor, as does LHV, but gross heating value also includes liquid water in the fuel prior to combustion. This value is important for fuels like
wood Wood is a porous and fibrous structural tissue found in the stems and roots of tree In botany, a tree is a perennial plant with an elongated Plant stem, stem, or trunk (botany), trunk, supporting branches and leaves in most species. ...

or
coal Coal is a combustible , Germany ) , image_map = , map_caption = , map_width = 250px , capital = Berlin , coordinates = , largest_city = capital , languages_type = Official language , languages = German language, German , ...

, which will usually contain some amount of water prior to burning.

# Measuring heating values

The higher heating value is experimentally determined in a
bomb calorimeter A calorimeter is an object used for calorimetry upSnellen direct calorimetry chamber, University of Ottawa. Calorimetry is the science or act of measuring changes in ''state variables'' of a body for the purpose of deriving the heat transf ...

. The combustion of a
stoichiometric Stoichiometry is the calculation of reactants and products in chemical reaction A chemical reaction is a process that leads to the chemical transformation of one set of chemical substances to another. Classically, chemical A chemical s ...
mixture of fuel and oxidizer (e.g. two moles of hydrogen and one mole of oxygen) in a steel container at is initiated by an ignition device and the reactions allowed to complete. When hydrogen and oxygen react during combustion, water vapor is produced. The vessel and its contents are then cooled to the original 25 °C and the higher heating value is determined as the heat released between identical initial and final temperatures. When the
lower heating value The heating value (or energy value or calorific value) of a Chemical substance, substance, usually a fuel or food (see food energy), is the amount of heat released during the combustion of a specified amount of it. The ''calorific value'' is the t ...
(LHV) is determined, cooling is stopped at 150 °C and the reaction heat is only partially recovered. The limit of 150 °C is based on
acid gasAcid gas is a particular typology of natural gas Natural gas (also called fossil gas; sometimes just gas) is a naturally occurring hydrocarbon gas mixture consisting primarily of methane, but commonly including varying amounts of other higher a ...
dew-point. Note: Higher heating value (HHV) is calculated with the product of water being in liquid form while lower heating value (LHV) is calculated with the product of water being in vapor form.

# Relation between heating values

The difference between the two heating values depends on the chemical composition of the fuel. In the case of pure carbon or carbon monoxide, the two heating values are almost identical, the difference being the sensible heat content of carbon dioxide between 150 °C and 25 °C. (
Sensible heatSensible heat is heat In thermodynamics, heat is energy in transfer to or from a thermodynamic system, by mechanisms other than Work (thermodynamics), thermodynamic work or Mass transfer, transfer of matter. The various mechanisms of energy tr ...
exchange causes a change of temperature, while
latent heat Latent heat (also known as latent energy or heat of transformation) is energy released or absorbed, by a body or a thermodynamic system A thermodynamic system is a body of matter In classical physics and general chemistry, matter is any su ...
phase transition In chemistry Chemistry is the scientific Science () is a systematic enterprise that builds and organizes knowledge Knowledge is a familiarity or awareness, of someone or something, such as facts A fact is an occurrence in ...
s at constant temperature. Examples:
heat of vaporization The enthalpy of vaporization (symbol ), also known as the (latent) heat of vaporization or heat of evaporation, is the amount of energy (enthalpy Enthalpy , a property of a thermodynamic system, is the sum of the system's internal energy and ...
or
heat of fusion The enthalpy of fusion of a substance, also known as (latent) heat of fusion is the change in its enthalpy Enthalpy is a property of a thermodynamic system A thermodynamic system is a body of matter and/or radiation, confined in space by walls ...
.) For
hydrogen Hydrogen is the chemical element with the Symbol (chemistry), symbol H and atomic number 1. Hydrogen is the lightest element. At standard temperature and pressure, standard conditions hydrogen is a gas of diatomic molecules having the che ...

the difference is much more significant as it includes the sensible heat of water vapor between 150 °C and 100 °C, the latent heat of condensation at 100 °C, and the sensible heat of the condensed water between 100 °C and 25 °C. All in all, the higher heating value of hydrogen is 18.2% above its lower heating value (142MJ/kg vs. 120MJ/kg). For
hydrocarbons In organic chemistry Organic chemistry is a branch of chemistry that studies the structure, properties and reactions of organic compounds, which contain carbon in covalent bonding.Clayden, J.; Greeves, N. and Warren, S. (2012) ''Organic Chemistry ...
the difference depends on the hydrogen content of the fuel. For
gasoline Gasoline () or petrol () (see the #Etymology, etymology for naming differences and the use of the term ''gas'') is a transparent, petroleum-derived flammable liquid that is used primarily as a fuel in most spark-ignition engine, spark-ignite ...

and
diesel Diesel may refer to: * Diesel engine, an internal combustion engine where ignition is caused by compression * Diesel fuel, a liquid fuel used in diesel engines * Diesel locomotive, a railway locomotive in which the prime mover is a diesel engine ...
the higher heating value exceeds the lower heating value by about 10% and 7%, respectively, and for natural gas about 11%. A common method of relating HHV to LHV is: : $\mathrm = \mathrm + H_\mathrm\left\left(\frac\right\right)$ where ''H''v is the heat of vaporization of water, ''n'',out is the number of moles of water vaporized and ''n''fuel,in is the number of moles of fuel combusted. * Most applications that burn fuel produce water vapor, which is unused and thus wastes its heat content. In such applications, the lower heating value must be used to give a 'benchmark' for the process. * However, for true energy calculations in some specific cases, the higher heating value is correct. This is particularly relevant for
natural gas Natural gas (also called fossil gas; sometimes just gas) is a naturally occurring hydrocarbon gas mixture consisting of methane and commonly including varying amounts of other higher alkanes, and sometimes a small percentage of carbon dioxid ...

, whose high
hydrogen Hydrogen is the chemical element with the Symbol (chemistry), symbol H and atomic number 1. Hydrogen is the lightest element. At standard temperature and pressure, standard conditions hydrogen is a gas of diatomic molecules having the che ...

content produces much water, when it is burned in
condensing boiler Condensing boilers are water heaters fueled by gas or oil. They achieve high efficiency (typically greater than 90% on the higher heating value) by condensing water vapour in the exhaust gases and so recovering its latent heat of vaporisation, w ...
s and
power plantsPower Station or The Power Station may refer to: * Power station, a facility for the generation of electricity Music * The Power Station (band), a 1980s supergroup ** The Power Station (album), ''The Power Station'' (album), a 1985 album by The Pow ...
with
flue-gas condensation Flue gas condensation is a process, where flue gas Flue gas is the gas exiting to the atmosphere via a flue, which is a pipe or channel for conveying exhaust gases from a fireplace, oven, furnace, boiler Poland Poland ( pl, Polska ), o ...
that condense the water vapor produced by combustion, recovering heat which would otherwise be wasted.

# Usage of terms

Engine manufacturers typically rate their engines fuel consumption by the lower heating values since the exhaust is never condensed in the engine, and doing this allows them to publish more attractive numbers than are used in conventional power plant terms. The conventional power industry had used HHV (high heat value) exclusively for decades, even though virtually all of these plants did not condense exhaust either. American consumers should be aware that the corresponding fuel-consumption figure based on the higher heating value will be somewhat higher. The difference between HHV and LHV definitions causes endless confusion when quoters do not bother to state the convention being used. since there is typically a 10% difference between the two methods for a power plant burning natural gas. For simply benchmarking part of a reaction the LHV may be appropriate, but HHV should be used for overall energy efficiency calculations if only to avoid confusion, and in any case, the value or convention should be clearly stated.

# Accounting for moisture

Both HHV and LHV can be expressed in terms of AR (all moisture counted), MF and MAF (only water from combustion of hydrogen). AR, MF, and MAF are commonly used for indicating the heating values of coal: * AR (as received) indicates that the fuel heating value has been measured with all moisture- and ash-forming minerals present. * MF (moisture-free) or dry indicates that the fuel heating value has been measured after the fuel has been dried of all inherent moisture but still retaining its ash-forming minerals. * MAF (moisture- and ash-free) or DAF (dry and ash-free) indicates that the fuel heating value has been measured in the absence of inherent moisture- and ash-forming minerals.

# Heat of combustion tables

; Note * There is no difference between the lower and higher heating values for the combustion of carbon, carbon monoxide and sulfur since no water is formed during the combustion of those substances. * BTU/lb values are calculated from MJ/kg (1 MJ/kg = 430 BTU/lb).

# Higher heating values of natural gases from various sources

The
International Energy Agency The International Energy Agency (IEA; french: Agence internationale de l'énergie) is a Paris Paris () is the Capital city, capital and List of communes in France with over 20,000 inhabitants, most populous city of France, with an estima ...
reports the following typical higher heating values per Standard cubic metre of gas: *
Algeria ) , image_map = Algeria (centered orthographic projection).svg , map_caption = , image_map2 = , capital = Algiers , coordinates = , largest_city = capital , religion = , official_languages = , languages_type = Oth ...

: 39.57MJ/Sm3 *
Bangladesh Bangladesh (, bn, বাংলাদেশ, ), officially the People's Republic of Bangladesh, is a country in South Asia South Asia is the southern region of Asia, which is defined in both geography, geographical and culture, ethno-c ...

: 36.00MJ/Sm3 *
Canada Canada is a country in the northern part of North America North America is a continent A continent is any of several large landmasses. Generally identified by convention (norm), convention rather than any strict criteria, ...

: 39.00MJ/Sm3 *
China China (), officially the People's Republic of China (PRC; ), is a country in East Asia East Asia is the eastern region of Asia Asia () is Earth's largest and most populous continent, located primarily in the Eastern Hemisphere ...

: 38.93MJ/Sm3 *
Indonesia Indonesia ( ), officially the Republic of Indonesia ( id, Republik Indonesia, links=yes ), is a country in Southeast Asia Southeast Asia, also spelled South East Asia and South-East Asia, and also known as Southeastern Asia or SEA, is t ...

: 40.60MJ/Sm3 *
Iran Iran ( fa, ایران ), also called Persia, and officially the Islamic Republic of Iran, is a country in Western Asia Western Asia, West Asia, or Southwest Asia, is the westernmost subregion A subregion is a part of a larger regio ...

: 39.36MJ/Sm3 *
Netherlands ) , national_anthem = ( en, "William of Nassau") , image_map = EU-Netherlands.svg , map_caption = , image_map2 = BES islands location map.svg , map_caption2 = , image_map3 ...

: 33.32MJ/Sm3 *
Norway Norway, officially the Kingdom of Norway,Names in the official and recognised languages: Bokmål Bokmål (, ; literally "book tongue") is an official written standard for the Norwegian language Norwegian (Norwegian: ''norsk'') is a Nort ...

: 39.24MJ/Sm3 *
Pakistan Pakistan, . Pronounced variably in English as , , , and . officially the Islamic Republic of Pakistan, is a country in South Asia. It is the world's List of countries and dependencies by population, fifth-most populous country, with a popul ...

: 34.90MJ/Sm3 *
Qatar Qatar (, , or ; ar, قطر, Qaṭar ; local vernacular pronunciation: ), officially the State of Qatar,) is a country in Western Asia. It occupies the small Qatar Peninsula on the northeastern coast of the Arabian Peninsula, and shares it ...

: 41.40MJ/Sm3 *
Russia Russia ( rus, link=no, Россия, Rossiya, ), or the Russian Federation, is a country spanning Eastern Europe Eastern Europe is the eastern region of . There is no consistent definition of the precise area it covers, partly because th ...

: 38.23MJ/Sm3 *
Saudi Arabia (''Shahada'') , national_anthem = "National Anthem of Saudi Arabia, " "National Anthem of Saudi Arabia" , image_map = Saudi Arabia (orthographic projection).svg , capital = Riyadh , coordinates ...

: 38.00MJ/Sm3 *
Turkmenistan Turkmenistan ( or ; tk, Türkmenistan, ), also known as Turkmenia, is a landlocked A landlocked country is a country that does not have territory connected to an ocean or whose coastlines lie on endorheic basin, endorheic basins. There ar ...

: 37.89MJ/Sm3 *
United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain,Usage is mixed. The Guardian' and Telegraph' use Britain as a synonym for the United Kingdom. Some prefer to use Britain as shorth ...

: 39.71MJ/Sm3 *
United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country Continental United States, primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., ...

: 38.42MJ/Sm3 *
Uzbekistan Uzbekistan (, ; uz, Ozbekiston, ), officially the Republic of Uzbekistan ( uz, Ozbekiston Respublikasi), is a landlocked country A country is a distinct territory, territorial body or political entity. It is often referred to as the land ...

: 37.89MJ/Sm3 The lower heating value of natural gas is normally about 90% of its higher heating value. This table is in Standard cubic metres (1
atm ATM or atm often refers to: * Atmosphere (unit) or atm, a unit of atmospheric pressure * Automated teller machine, a cash dispenser or cash machine ATM or atm may also refer to: Computing * ATM (computer), a ZX Spectrum clone developed in Mos ...
, 15°C), to convert to values per Normal cubic metre (1atm, 0°C), multiply above table by 1.0549.

Energy density In physics Physics is the natural science that studies matter, its Elementary particle, fundamental constituents, its Motion (physics), motion and behavior through Spacetime, space and time, and the related entities of energy and force. "P ...

*
Energy value of coal The energy value of coal Coal is a combustible black or brownish-black sedimentary rock, formed as rock strata (Argentina Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country located most ...
*
Exothermic reaction In thermochemistry, an exothermic reaction is a "reaction for which the overall Standard enthalpy of reaction, standard enthalpy change Δ''H''⚬ is negative." Exothermic reactions usually release heat and entail the replacement of weak bonds wi ...
*
Fire BBQ. Fire is the rapid oxidation of a material in the exothermic chemical process of combustion, releasing heat, light, and various reaction Product (chemistry), products. Fire is hot because the conversion of the weak double bond in molecula ...

* Fuel efficiency#Energy content of fuel *
Food energy Food energy is chemical energy Chemical energy is the energy of chemical substance A chemical substance is a form of matter In classical physics and general chemistry, matter is any substance that has mass and takes up space by havin ...
*
Internal energy The internal energy of a thermodynamic system A thermodynamic system is a body of matter In classical physics and general chemistry, matter is any substance that has mass and takes up space by having volume. All everyday objects that ca ...
*
Thermal efficiency In thermodynamics Thermodynamics is a branch of physics that deals with heat, Work (thermodynamics), work, and temperature, and their relation to energy, entropy, and the physical properties of matter and radiation. The behavior of these quan ...
* Wobbe index: heat density *
ISO 15971 {{short description, Standard energy measurement of natural gas ISO 15971 is an ISO The International Organization for Standardization (ISO ) is an international standard An international standard is a technical standard A technical standard is ...
*
Electrical efficiency The efficiency of a system in electronics Electronics comprises the physics, engineering, technology and applications that deal with the emission, flow and control of electrons in vacuum and matter. It uses active devices to control electron fl ...
*
Mechanical efficiency Mechanical efficiency is a dimensionless number that measures the effectiveness of a machine A machine is a man-made device that uses power to apply forces and control movement to perform an action. Machines can be driven by animals and peo ...
*
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. Examples *Clock rate In computing Computing is any goal-oriented activity requiring, benefiting from, or creat ...
*
Cost of electricity by source Different methods of electricity generation Electricity generation is the process of generating electric power Electric power is the rate, per unit time, at which electrical energy is transferred by an electric circuit. The SI unit of p ...

*
Energy conversion efficiency Energy conversion efficiency (''η'') is the ratio In mathematics, a ratio indicates how many times one number contains another. For example, if there are eight oranges and six lemons in a bowl of fruit, then the ratio of oranges to lemons i ...