Editing Natural gas

{{Short description|Gaseous fossil fuel}}
{{Distinguish|gasoline|biogas|liquefied petroleum gas}}
{{About||the Canadian band|Natural Gas (band)}}
{{Use dmy dates|date=September 2020}}
{{Use American English|date=February 2022}}

[[File:Gas-natural.jpg|alt=Close-up image of a natural gas burner on a stove showing the characteristic blue hue of a natural gas flame.|thumb|300x300px|Natural gas burning on a gas stove]]

[[File:Chuhuo.jpg|thumb|Burning of natural gas coming out of the ground]]

'''Natural gas''' (also '''fossil gas, methane gas''', and '''gas''') is a naturally occurring compound of gaseous [[hydrocarbon]]s, primarily [[methane]] (95%),<ref>{{cite web | url=https://group.met.com/en/media/energy-insight/composition-of-natural-gas | title=Composition of natural gas: Understanding its key elements}}</ref> small amounts of higher [[alkane]]s, and traces of [[carbon dioxide]] and [[nitrogen]], [[hydrogen sulfide]] and [[helium]].<ref>{{Cite web |title=Background |url=http://www.naturalgas.org/overview/background |archive-url=https://web.archive.org/web/20140709040340/http://www.naturalgas.org/overview/background |archive-date=2014-07-09 |access-date=2012-07-14 |publisher=Naturalgas.org}}</ref> Methane is a colorless and odorless gas, and, after carbon dioxide, is the second-greatest [[greenhouse gas]] that contributes to global [[climate change]].<ref>{{cite book |doi=10.1002/14356007.a17_073.pub2 |chapter=Natural Gas |title=Ullmann's Encyclopedia of Industrial Chemistry |date=2006 |last1=Hammer |first1=Georg |last2=Lübcke |first2=Torsten |last3=Kettner |first3=Roland |last4=Pillarella |first4=Mark R. |last5=Recknagel |first5=Herta |last6=Commichau |first6=Axel |last7=Neumann |first7=Hans-Joachim |last8=Paczynska-Lahme |first8=Barbara |isbn=978-3-527-30385-4 }}</ref><ref name="Kashtan-2023">{{Cite journal |last1=Kashtan |first1=Yannai S. |last2=Nicholson |first2=Metta |last3=Finnegan |first3=Colin |last4=Ouyang |first4=Zutao |last5=Lebel |first5=Eric D. |last6=Michanowicz |first6=Drew R. |last7=Shonkoff |first7=Seth B.C. |last8=Jackson |first8=Robert B. |date=June 15, 2023 |title=Gas and Propane Combustion from Stoves Emits Benzene and Increases Indoor Air Pollution |journal=Environmental Science & Technology |volume=57 |issue=26 |pages=9653–9663 |doi=10.1021/acs.est.2c09289 |pmid=37319002 |pmc=10324305 |bibcode=2023EnST...57.9653K }}</ref> Because natural gas is odorless, a commercial [[odorizer]], such as [[Methanethiol]] (mercaptan brand), that smells of [[hydrogen sulfide]] (rotten eggs) is added to the gas for the ready detection of gas leaks.<ref>{{Cite web |title=Why Does Natural Gas Smell Like Rotten Eggs? &#124; Metropolitan Utilities District |url=https://www.mudomaha.com/blog/why-does-natural-gas-smell-rotten-eggs}}</ref>

Natural gas is a [[fossil fuel]] that is formed when layers of [[organic matter]] (primarily marine microorganisms)<ref>{{Cite web |title=How Natural Gas Is Formed {{!}} Union of Concerned Scientists |url=https://www.ucsusa.org/resources/how-natural-gas-formed |access-date=2022-05-03 |website=www.ucsusa.org |language=en}}</ref> are thermally decomposed under oxygen-free conditions, subjected to intense heat and pressure underground over millions of years.<ref name="eiaex">{{Cite web |title=Natural gas explained |url=https://www.eia.gov/energyexplained/natural-gas/ |access-date=2020-09-30 |publisher=[[U.S. Energy Information Administration]]}}</ref> The energy that the decayed organisms originally obtained from the sun via [[photosynthesis]] is stored as chemical energy within the molecules of methane and other hydrocarbons.<ref name="epa_ng">{{Cite web |title=Electricity from Natural Gas |url=http://www.epa.gov/cleanenergy/energy-and-you/affect/natural-gas.html |archive-url=https://web.archive.org/web/20140606215324/http://www.epa.gov/cleanenergy/energy-and-you/affect/natural-gas.html |archive-date=2014-06-06 |access-date=2013-11-10}}</ref>

Natural gas can be burned for heating, cooking,<ref>{{Cite news |title=We need to talk about your gas stove, your health and climate change |language=en |work=NPR.org |url=https://www.npr.org/2021/10/07/1015460605/gas-stove-emissions-climate-change-health-effects |access-date=2022-05-03}}</ref> and [[Gas-fired power plant|electricity generation]]. Consisting mainly of methane, natural gas is rarely used as a chemical [[Raw material|feedstock]].

The extraction and consumption of natural gas is a major industry.  When burned for [[Furnace (central heating)|heat]] or [[Gas-fired power plant|electricity]], natural gas emits fewer toxic air pollutants, less carbon dioxide, and almost no particulate matter compared to other fossil fuels.<ref>{{Cite web |title=Natural gas and the environment |url=https://www.eia.gov/energyexplained/natural-gas/natural-gas-and-the-environment.php |access-date=2020-09-30 |publisher=[[U.S. Energy Information Administration]]}}</ref> However, [[gas venting]] and unintended [[fugitive emissions]] throughout the [[supply chain]] can result in natural gas having a similar [[carbon footprint]] to other fossil fuels overall.<ref>{{Cite web |date=2020-02-19 |title=Natural gas is a much 'dirtier' energy source, carbon-wise, than we thought |url=https://www.nationalgeographic.com/science/article/super-potent-methane-in-atmosphere-oil-gas-drilling-ice-cores |archive-url=https://web.archive.org/web/20210218011119/https://www.nationalgeographic.com/science/article/super-potent-methane-in-atmosphere-oil-gas-drilling-ice-cores |url-status=dead |archive-date=18 February 2021 |access-date=2022-04-03 |website=Science |language=en}}</ref>

Natural gas can be found in underground [[geological formation]]s, often alongside other fossil fuels like [[coal]] and [[Petroleum|oil]] (petroleum). Most natural gas has been created through either biogenic or thermogenic processes. Thermogenic gas takes a much longer period of time to form and is created when organic matter is heated and compressed deep underground.<ref>{{Cite web |title=Organic Origins of Petroleum |url=http://energy.er.usgs.gov/gg/research/petroleum_origins.html |archive-url=https://web.archive.org/web/20100527093933/http://energy.er.usgs.gov/gg/research/petroleum_origins.html |archive-date=2010-05-27 |publisher=US Geological Survey}}</ref><ref name="eiaex" />  Methanogenic organisms produce methane from a variety of sources, principally carbon dioxide.

{{Anchor|impurities}}
During petroleum production, natural gas is sometimes [[Gas flare|flared]] rather than being collected and used. Before natural gas can be burned as a fuel or used in manufacturing processes, it almost always has to be [[natural gas processing|processed]] to remove impurities such as water. The byproducts of this processing include [[ethane]], [[propane]], [[butane]]s, [[pentane]]s, and higher molecular weight hydrocarbons. Hydrogen sulfide (which may be converted into pure [[sulfur]]), [[carbon dioxide]], [[water vapor]], and sometimes [[helium]] and [[nitrogen]] must also be removed.

Natural gas is sometimes informally referred to simply as "gas", especially when it is being compared to other energy sources, such as oil,  coal or renewables. However, it is not to be confused with [[gasoline]], which is also shortened in colloquial usage to "gas", especially in North America.<ref>{{Cite web |title=Natural gas |url=https://courses.lumenlearning.com/geology/chapter/reading-natural-gas/ |access-date=2022-03-01 |website=Lumen}}</ref>

Natural gas is measured in [[standard cubic meter]]s or [[standard cubic feet]]. The density compared to air ranges from 0.58 (16.8&nbsp;g/mole, 0.71&nbsp;kg per standard cubic meter) to as high as 0.79 (22.9&nbsp;g/mole, 0.97&nbsp;kg per scm), but generally less than 0.64 (18.5&nbsp;g/mole, 0.78&nbsp;kg per scm).<ref>{{Cite book |title=Chemical Engineers' Handbook |date=1973 |editor-first1=Robert |editor-last1=Perry |editor-first2=Cecil |editor-last2=Chilton |pages=9–12}}</ref> For comparison, pure methane (16.0425&nbsp;g/mole) has a density 0.5539 times that of air (0.678&nbsp;kg per standard cubic meter).

==Name==
In the early 1800s, natural gas became known as "natural" to distinguish it from the dominant gas fuel at the time, [[coal gas]].<ref>{{Cite web |date=2022-03-21 |title=We need to talk about how we talk about natural gas |url=https://www.canarymedia.com/articles/fossil-fuels/we-need-to-talk-about-how-we-talk-about-natural-gas |access-date=2023-07-27 |website=Canary Media |language=en}}</ref> Unlike coal gas, which is manufactured by heating coal, natural gas can be extracted from the ground in its native gaseous form. When the use of natural gas overtook the use of coal gas in English speaking countries in the 20th century, it was increasingly referred to as simply "gas."<ref>{{Cite book |url=https://www.oed.com/dictionary/gas |title=Oxford English Dictionary}}</ref> In order to highlight its role in exacerbating the [[climate crisis]], however, many organizations have criticized the continued use of the word "natural" in referring to the gas. These advocates prefer the term "fossil gas" or "methane gas" as better conveying to the public its climate threat.<ref>{{Cite web |last=Leber |first=Rebecca |date=2022-02-10 |title=The end of natural gas has to start with its name |url=https://www.vox.com/22912760/natural-gas-methane-rename |access-date=2023-07-27 |website=Vox |language=en}}</ref><ref>{{Cite web |title="Natural" Gas is Not Clean Energy - It's Climate Endangering Methane Gas |url=https://www.sierraclub.org/minnesota/blog/2022/01/natural-gas-not-clean-energy-it-s-climate-endangering-methane-gas |access-date=2023-07-27 |website=www.sierraclub.org |language=en}}</ref><ref>{{Cite web |last=Geman |first=Ben |date=Sep 10, 2021 |title=The high stakes of the natural gas branding battle |url=https://www.axios.com/2021/09/10/natural-gas-branding-battle}}</ref> A 2020 study of Americans' perceptions of the fuel found that, across political identifications, the term "methane gas" led to better estimates of its harms and risks.<ref>{{Cite web |title=Should it be called "natural gas" or "methane"? |url=https://climatecommunication.yale.edu/publications/should-it-be-called-natural-gas-or-methane/ |access-date=2023-07-27 |website=Yale Program on Climate Change Communication |language=en-US}}</ref>

==History==
[[File:Residential natural gas bill USA 1834.jpg|thumb|A gas bill from [[Baltimore]], Maryland, 1834, for manufactured coal gas, before the introduction of ground-extracted methane gas.]]

Natural gas can come out of the ground and cause a long-burning fire. In [[ancient Greece]], the gas flames at [[Mount Chimaera]] contributed to the legend of the fire-breathing creature [[Chimera (mythology)|Chimera]]. In [[ancient China]], gas resulting from the drilling for [[Brine (solution)|brines]] was first used by about 400 BC.<ref>{{Cite web |last1=Eric Hadley-Ives |last2=Chun-Chih Hadley-Ives |title=First Oil Wells |url=http://www.historylines.net/history/chinese/oil_well.html |website=History Lines}}</ref> The Chinese transported gas seeping from the ground in crude pipelines of bamboo to where it was used to boil salt water to [[Salt in Chinese history|extract the salt]] in the [[Ziliujing District]] of [[Sichuan]].<ref>{{Cite web |title=History |url=http://naturalgas.org/overview/history/ |access-date=2016-12-01 |publisher=NaturalGas.org}}</ref><ref>{{Cite book |last=Abbott |first=Malcolm |title=The Economics of the Gas Supply Industry |date=2016 |publisher=Routledge |isbn=978-1-138-99879-7 |page=185}}</ref>

Natural gas was not widely used before the development of long distance pipelines in the early 20th century. Before that, most use was near to the source of the well, and the predominant gas for fuel and lighting during the industrial revolution was manufactured coal gas.<ref>{{Cite web |title=Britannica Academic |url=https://academic.eb.com/?target=%2Flevels%2Fcollegiate%2Farticle%2Fnatural-gas%2F110439 |access-date=2023-07-27 |website=academic.eb.com}}</ref>

The history of natural gas in the United States begins with localized use. In the seventeenth century, French missionaries witnessed the American Indians setting fire to natural gas seeps around [[Lake Erie]], and scattered observations of these seeps were made by European-descended settlers throughout the eastern seaboard through the 1700s.<ref name="encyclopedia.com">{{Cite web |title=Natural Gas Industry {{!}} Encyclopedia.com |url=https://www.encyclopedia.com/history/dictionaries-thesauruses-pictures-and-press-releases/natural-gas-industry |access-date=2023-07-27 |website=www.encyclopedia.com}}</ref> In 1821, William Hart dug the first commercial natural gas well in the United States at [[Fredonia, New York]], United States, which led in 1858 to the formation of the [[Fredonia Gas Light Company]].<ref>{{Cite web |title=A Brief History of Natural Gas - APGA |url=https://www.apga.org/apgamainsite/aboutus/facts/history-of-natural-gas |access-date=2019-02-18 |website=www.apga.org}}</ref> Further such ventures followed near wells in other states, until technological innovations allowed the growth of major long distance pipelines from the 1920s onwards.<ref name="encyclopedia.com" />

By 2009, {{convert|66,000|km3|mi3|abbr=on}} (or 8%) had been used out of the total {{convert|850,000|km3|mi3|abbr=on}} of estimated remaining recoverable reserves of natural gas.<ref name="worldenergyoutlook.org">{{Cite web |date=2009 |title=World Energy Outlook 2009 |url=http://www.worldenergyoutlook.org/media/weowebsite/2009/WEO2009.pdf |website=International Energy Agency}}</ref>

==Sources==
{{See also|List of natural gas fields|List of countries by natural gas proven reserves|List of countries by natural gas production}}

===Natural gas===
[[File:BarnettShaleDrilling-9323.jpg|thumb|upright|Natural gas [[drilling rig]] in Texas, US]]
In the 19th century, natural gas was primarily obtained as a by-product of [[Oil well|producing oil]]. The small, light gas carbon chains came out of solution as the extracted fluids underwent pressure reduction from the [[Petroleum reservoir|reservoir]] to the surface, similar to uncapping a soft drink bottle where the carbon dioxide [[effervesce]]s. The gas was often viewed as a by-product, a hazard, and a disposal problem in active oil fields. The large volumes produced could not be used until relatively expensive [[pipeline transport|pipeline]] and [[natural gas storage|storage]] facilities were constructed to deliver the gas to consumer markets.

Until the early part of the 20th century, most natural gas associated with oil was either simply released or [[Gas flare|burned off]] at oil fields. [[Gas venting]] and [[production flaring]] are still practised in modern times, but efforts are ongoing around the world to retire them, and to replace them with other commercially viable and useful alternatives.<ref>{{Cite web |title=Global Gas Flaring Reduction Partnership |url=https://sustainabledevelopment.un.org/partnership/?p=1532 |access-date=2019-12-29 |publisher=[[United Nations]]}}</ref><ref>{{Cite web |title=UN Climate Initiatives Platform - Zero Routine Flaring by 2030 |url=http://climateinitiativesplatform.org/index.php/Zero_Routine_Flaring_by_2030 |access-date=2019-12-29 |publisher=[[United Nations]]}}</ref>

In addition to transporting gas via pipelines for use in power generation, other end uses for natural gas include export as [[LNG|liquefied natural gas]] (LNG) or conversion of natural gas into other liquid products via [[gas to liquids]] (GTL) technologies. GTL technologies can convert natural gas into liquids products such as gasoline, diesel or jet fuel. A variety of GTL technologies have been developed, including [[Fischer–Tropsch]] (F–T), methanol to gasoline (MTG) and [[syngas to gasoline plus]] (STG+). F–T produces a synthetic crude that can be further refined into finished products, while MTG can produce synthetic gasoline from natural gas. STG+ can produce drop-in gasoline, diesel, jet fuel and aromatic chemicals directly from natural gas via a single-loop process.<ref name="STG+">{{Cite web |date=February 2013 |title=Introduction to STG+ Technology |url=http://www.primusge.com/press-room/white-papers/ |access-date=2013-03-05 |website=Primus Green Energy}}</ref> In 2011, [[Royal Dutch Shell|Royal Dutch Shell's]] {{convert|140000|oilbbl|m3|sp=us}} per day F–T plant went into operation in [[Qatar]].<ref>{{Cite web |date=2011-06-13 |title=First cargo of Pearl GTL products ship from Qatar |url=http://www.shell.com/media/news-and-media-releases/2011/first-cargo-pearl.html |access-date=2017-11-19 |website=Shell Global}}</ref>

Natural gas can be "associated" (found in [[oil field]]s), or "non-associated" (isolated in [[natural gas field]]s), and is also found in [[coal bed]]s (as [[coalbed methane]]).<ref>{{Cite web |title=Extraction |url=http://www.naturalgas.org/naturalgas/extraction.asp |archive-url=https://web.archive.org/web/20130708145258/http://www.naturalgas.org/naturalgas/extraction.asp |archive-date=2013-07-08 |publisher=NaturalGas.org}}</ref> It sometimes contains a significant amount of [[ethane]], [[propane]], [[butane]], and [[pentane]]—heavier hydrocarbons removed for commercial use prior to the [[methane]] being sold as a consumer fuel or chemical plant feedstock. Non-hydrocarbons such as [[carbon dioxide]], [[nitrogen]], [[helium]] (rarely), and [[hydrogen sulfide]] must also be removed before the natural gas can be transported.<ref>{{Cite web |title=Natural gas overview |url=http://www.naturalgas.org/overview/background.asp |url-status=dead |archive-url=https://web.archive.org/web/20110101063224/http://naturalgas.org/overview/background.asp |archive-date=2011-01-01 |access-date=2011-02-06 |publisher=Naturalgas.org}}</ref>

Natural gas extracted from oil wells is called casinghead gas (whether or not truly produced up the annulus and through a casinghead outlet) or associated gas. The [[natural gas industry]] is extracting an increasing quantity of gas from challenging, [[Unconventional (oil & gas) reservoir|unconventional]] [[History of the petroleum industry in Canada (natural gas)#Unconventional gas|resource types]]: [[sour gas]], [[tight gas]], [[shale gas]], and [[coalbed methane]].

There is some disagreement on which country has the largest proven gas reserves. Sources that consider that Russia has by far the largest proven reserves include the US [[Central Intelligence Agency]] (47,600&nbsp;km<sup>3</sup>)<ref>{{Cite encyclopedia |title=Natural Gas – Proved Reserves |encyclopedia=The World Factbook |publisher=Central Intelligence Agency |url=https://www.cia.gov/library/publications/the-world-factbook/rankorder/2253rank.html |access-date=2013-12-01 |archive-url=https://web.archive.org/web/20170307234405/https://www.cia.gov/library/publications/the-world-factbook/rankorder/2253rank.html |archive-date=2017-03-07 |url-status=dead}}</ref> and [[Energy Information Administration]] (47,800&nbsp;km<sup>3</sup>),<ref>US Energy Information Administration, International statistics, accessed 1 December 2013.</ref><ref>{{Cite web |title=U.S. Crude Oil, Natural Gas, and Natural Gas Proved Reserves, Year-end 2017 |url=https://www.eia.gov/naturalgas/crudeoilreserves/ |access-date=2019-08-26 |website=www.eia.gov}}</ref> as well as the [[Organization of Petroleum Exporting Countries]] (48,700&nbsp;km<sup>3</sup>).<ref>{{Cite web |title=Table 3.2 – World Proven Natural Gas Reserves by Country |url=http://www.opec.org/library/Annual%20Statistical%20Bulletin/interactive/current/FileZ/XL/T32.HTM |url-status=dead |archive-url=https://web.archive.org/web/20180227183441/http://www.opec.org/library/Annual%20Statistical%20Bulletin/interactive/current/FileZ/XL/T32.HTM |archive-date=2018-02-27 |access-date=2013-12-01 |publisher=OPEC}}</ref> Contrarily, [[BP]] credits Russia with only 32,900&nbsp;km<sup>3</sup>,<ref>{{Cite web |title=BP Statistical Review of World Energy June 2013 |url=http://www.bp.com/content/dam/bp/pdf/statistical-review/statistical_review_of_world_energy_2013.pdf |archive-url=https://web.archive.org/web/20131204120328/http://www.bp.com/content/dam/bp/pdf/statistical-review/statistical_review_of_world_energy_2013.pdf |archive-date=2013-12-04 |website=BP}}</ref> which would place it in second, slightly behind Iran (33,100 to 33,800&nbsp;km<sup>3</sup>, depending on the source).
[[File:Countries by Natural Gas Proven Reserves (2014).svg|thumb|upright=2|Countries by [[List of countries by natural gas proven reserves|natural gas proven reserves]] (2014), based on data from The World Factbook]]

It is estimated that there are about 900,000&nbsp;km<sup>3</sup> of "unconventional" gas such as shale gas, of which 180,000&nbsp;km<sup>3</sup> may be recoverable.<ref>{{Cite web |last=Helen Knight |date=2010-06-12 |title=Wonderfuel: Welcome to the age of unconventional gas |url=https://www.newscientist.com/article/mg20627641.100-wonderfuel-welcome-to-the-age-of-unconventional-gas.html?full=true |url-access=subscription |website=[[New Scientist]] |pages=44–47}}</ref> In turn, many studies from [[MIT]], [[Black & Veatch]] and the [[US Department of Energy]] predict that natural gas will account for a larger portion of electricity generation and heat in the future.<ref>{{Cite web |last=Michael Kanellos |date=2011-06-09 |title=In Natural Gas, U.S. Will Move From Abundance to Imports |url=http://www.greentechmedia.com/articles/read/with-natural-gas-will-we-swap-oil-imports-for-gas-imports/ |website=Greentech Media}}</ref>{{Better source needed|reason=The current source is too old|date=October 2022}}

The world's largest gas field is the offshore [[South Pars/North Dome Gas-Condensate field]], shared between Iran and Qatar. It is estimated to have {{convert|51000|km3|mi3|sp=us}} of natural gas and {{convert|50|e9oilbbl|e9m3|abbr=off|sp=us}} of [[Natural-gas condensate|natural gas condensates]].

Because natural gas is not a pure product, as the reservoir pressure drops when non-associated gas is extracted from a field under [[Supercritical fluid|supercritical]] (pressure/temperature) conditions, the higher molecular weight components may partially condense upon isothermic depressurizing—an effect called [[retrograde condensation]]. The liquid thus formed may get trapped as the pores of the gas reservoir get depleted. One method to deal with this problem is to re-inject dried gas free of condensate to maintain the underground pressure and to allow re-evaporation and extraction of condensates. More frequently, the liquid condenses at the surface, and one of the tasks of the [[Natural gas processing|gas plant]] is to collect this condensate. The resulting liquid is called natural gas liquid (NGL) and has commercial value.

===Shale gas===
[[File:GasDepositDiagram.jpg|thumb|upright=2.0|The location of [[shale gas]] compared to other types of gas deposits]]
{{main|Shale gas}}

Shale gas is natural gas produced from [[shale]]. Because shale's matrix permeability is too low to allow gas to flow in economical quantities, shale gas wells depend on fractures to allow the gas to flow. Early shale gas wells depended on natural fractures through which gas flowed; almost all shale gas wells today require fractures artificially created by [[hydraulic fracturing]]. Since 2000, shale gas has become a major source of natural gas in the United States and Canada.<ref>{{Cite web |last=Mouawad |first=Jad |date=2009-06-17 |title=Estimate places natural gas reserves 35% higher |url=https://www.nytimes.com/2009/06/18/business/energy-environment/18gas.html |access-date=2009-10-25 |website=The New York Times}}</ref> Because of increased shale gas production the United States was in 2014 the number one natural gas producer in the world.<ref>{{Cite web |last=Morris Beschloss |date=2014-09-02 |title=U.S. Now World's Leading Natural Gas Producer |url=http://www.desertsun.com/story/money/industries/morrisbeschlosseconomics/2014/09/02/u-s-now-worlds-leading-natural-gas-producer/14976767/ |access-date=2014-11-04 |website=Desert Sun}}</ref> The production of shale gas in the United States has been described as a "shale gas revolution" and as "one of the landmark events in the 21st century."<ref>{{Cite journal |last1=Wang |first1=Qiang |last2=Chen |first2=Xi |last3=Jha |first3=Awadhesh N. |last4=Rogers |first4=Howard |date=February 2014 |title=Natural gas from shale formation – The evolution, evidences and challenges of shale gas revolution in United States |journal=Renewable and Sustainable Energy Reviews |volume=30 |pages=1–28 |doi=10.1016/j.rser.2013.08.065|bibcode=2014RSERv..30....1W }}</ref>

Following the increased production in the United States, shale gas exploration is beginning in countries such as Poland, China, and South Africa.<ref>{{Cite news |year=2012 |title=Poland Seeks to Boost Shale Gas Industry |work=Financial Times |url=http://www.ft.com/intl/cms/s/0/76c6ec14-17ad-11e2-9530-00144feabdc0.html#axzz29foGuSzc |url-status=live |url-access=subscription |access-date=2012-10-18 |archive-url=https://ghostarchive.org/archive/VA3Os |archive-date=2022-12-10}}</ref><ref>{{Cite web |last=Catherine T. Yang |date=2012-08-09 |title=China Drills into Shale Gas, Targeting Huge Reserves Amid Challenges |url=http://news.nationalgeographic.com/news/energy/2012/08/120808-china-shale-gas/ |archive-url=https://web.archive.org/web/20120810174014/http://news.nationalgeographic.com/news/energy/2012/08/120808-china-shale-gas/ |url-status=dead |archive-date=10 August 2012 |access-date=2012-10-18 |website=National Geographic}}</ref><ref>{{Cite news |last1=Franz Wild |last2=Andres R. Martinez |date=2012-09-07 |title=South Africa Allows Exploration of Shale Gas Resources |work=Bloomberg.com |url=https://www.bloomberg.com/news/2012-09-07/south-africa-allows-exploration-of-shale-gas-resources.html |url-access=subscription |access-date=2012-10-18}}</ref> Chinese geologists have identified the [[Sichuan Basin]] as a promising target for shale gas drilling, because of the similarity of shales to those that have proven productive in the United States. Production from the Wei-201 well is between 10,000 and 20,000 m<sup>3</sup> per day.<ref>{{Cite journal |last1=Zou |first1=Caineng |last2=Dong |first2=Dazhong |last3=Wang |first3=Shejiao |last4=Li |first4=Jianzhong |last5=Li |first5=Xinjing |last6=Wang |first6=Yuman |last7=Li |first7=Denghua |last8=Cheng |first8=Keming |date=December 2010 |title=Geological characteristics and resource potential of shale gas in China |journal=Petroleum Exploration and Development |volume=37 |issue=6 |pages=641–653 |doi=10.1016/S1876-3804(11)60001-3 |bibcode=2010PEDO...37..641Z |doi-access=free}}</ref> In late 2020, China National Petroleum Corporation claimed daily production of 20 million cubic meters of gas from its Changning-Weiyuan demonstration zone.<ref>{{Cite news |date=2020-10-13 |title=Shale gas production soars in SW China base |publisher=China Daily Information Co |agency=ChinaDaily.com.cn |url=https://www.chinadaily.com.cn/a/202010/13/WS5f852220a31024ad0ba7e5bd.html |access-date=2020-12-02}}</ref>{{Unreliable source?|date=November 2021}}

===Town gas===
{{Main|History of manufactured fuel gases}}

[[Town gas]] is a flammable gaseous fuel made by the destructive distillation of [[coal]]. It contains a variety of calorific gases including [[hydrogen]], [[carbon monoxide]], [[methane]], and other volatile [[hydrocarbon]]s, together with small quantities of non-calorific gases such as [[carbon dioxide]] and [[nitrogen]], and was used in a similar way to natural gas. This is a historical technology and is not usually economically competitive with other sources of fuel gas today.

Most town "gashouses" located in the eastern US in the late 19th and early 20th centuries were simple by-product [[coke (fuel)|coke]] ovens that heated bituminous coal in air-tight chambers. The gas driven off from the coal was collected and distributed through networks of pipes to residences and other buildings where it was used for cooking and lighting. (Gas heating did not come into widespread use until the last half of the 20th century.) The [[coal tar]] (or [[Bitumen|asphalt]]) that collected in the bottoms of the gashouse ovens was often used for roofing and other waterproofing purposes, and when mixed with sand and gravel was used for paving streets.

===Crystallized natural gas – clathrates===
Huge quantities of natural gas (primarily methane) exist in the form of [[methane clathrate|clathrates]] under sediment on offshore continental shelves and on land in arctic regions that experience [[permafrost]], such as those in [[Siberia]]. Hydrates require a combination of high pressure and low temperature to form.

In 2013, Japan Oil, Gas and Metals National Corporation (JOGMEC) announced that they had recovered commercially relevant quantities of natural gas from methane hydrate.<ref>{{Cite web |last=Tabuchi |first=Hiroko |author-link=Hiroko Tabuchi |date=2013-03-12 |title=An Energy Coup for Japan: 'Flammable Ice' |url=https://www.nytimes.com/2013/03/13/business/global/japan-says-it-is-first-to-tap-methane-hydrate-deposit.html |website=The New York Times}}</ref>

==Processing==
{{Main|Natural gas processing}}

[[File:Aderklaa - Gasstation.JPG|thumb|Natural gas processing plant in [[Aderklaa]], Lower Austria]]

The image below is a schematic [[Process flow diagram|block flow diagram]] of a typical natural gas processing plant. It shows the various unit processes used to convert raw natural gas into sales gas pipelined to the end user markets.

The block flow diagram also shows how processing of the raw natural gas yields byproduct sulfur, byproduct ethane, and [[natural gas liquids]] (NGL) propane, butanes and natural gasoline (denoted as [[pentanes]] +).<ref>{{Cite web |date=January 2006 |title=Natural Gas Processing: The Crucial Link Between Natural Gas Production and Its Transportation to Market |url=http://www.dnr.louisiana.gov/assets/docs/oilgas/naturalgas/ngprocess_20060131.pdf |access-date=2017-11-24 |publisher=Energy Information Administration, Office of Oil and Gas |via=The Louisiana Department of Natural Resources}}</ref><ref>{{Cite web |title=Natural Gas Processing |url=https://www.axens.net/our-offer/by-market/gases/natural-gas-processing.html |access-date=2017-11-24 |website=Axens}}</ref><ref>{{Cite book |last1=Arg |first1=S.R. |url=https://www.onepetro.org/conference-paper/SPE-157375-MS |title=Reliable & Efficient Feed Gas Preparation – A Key Enabler to Pearl GTL |last2=Engel |first2=D.C. |date=2012-01-01 |series=OnePetro |publisher=Society of Petroleum Engineers |isbn=9781613992012 |doi=10.2118/157375-MS |access-date=2015-06-11}}</ref><ref>{{Cite conference |last=Elliot |first=Doug |display-authors=etal |date=2005 |title=Benefits of Integrating NGL Extraction and LNG Liquefaction |url=http://lnglicensing.conocophillips.com/EN/publications/documents/AICHELNGNGLIntegrationPaper.pdf |conference=Prepared for Presentation at AIChE 2005 Spring National Meeting 5th Topical Conference on Natural Gas Utilization (TI) Session 16c – Gas |archive-url=https://web.archive.org/web/20130626080757/http://lnglicensing.conocophillips.com/EN/publications/documents/AICHELNGNGLIntegrationPaper.pdf |archive-date=2013-06-26}}</ref>

[[File:NatGasProcessing.svg|class=skin-invert-image|frame|center|Schematic flow diagram of a typical natural gas processing plant]]

==Demand==
{{See also|Gas depletion}}
[[File:World - Natural Gas Production of Countries.png|thumb|upright=2|[[List of countries by natural gas production|Natural gas extraction by countries]] in cubic meters per year around 2013]]{{Globalize section|date=October 2022|US}}
As of mid-2020, natural gas production in the US had peaked three times, with current levels exceeding both previous peaks. It reached 24.1&nbsp;trillion cubic feet per year in 1973, followed by a decline, and reached 24.5&nbsp;trillion cubic feet in 2001. After a brief drop, withdrawals increased nearly every year since 2006 (owing to the [[Shale gas in the United States#Barnett and beyond|shale gas boom]]), with 2017 production at 33.4&nbsp;trillion cubic feet and 2019 production at 40.7&nbsp;trillion cubic feet. After the third peak in December 2019, extraction continued to fall from March onward due to decreased demand caused by the [[COVID-19 pandemic in the United States|COVID-19 pandemic in the US]].<ref name="EIAThirdPeak">{{Cite web |title=U.S. Natural Gas Gross Withdrawals |url=http://www.eia.gov/dnav/ng/hist/n9010us2m.htm |access-date=2020-09-28 |website=U.S. Energy Information Administration (EIA)}}</ref>

The [[2021 global energy crisis]] was driven by a global surge in demand as the world quit the economic recession caused by COVID-19, particularly due to strong energy demand in Asia.<ref>{{Cite news |date=2021-10-08 |title=Covid is at the center of world's energy crunch, but a cascade of problems is fueling it |work=NBC News |url=https://www.nbcnews.com/news/world/covid-center-world-energy-crunch-cascade-problems-fuel-rcna2688}}</ref>

==Storage and transport==
{{see also|List of natural gas pipelines}}
[[File:Polyethylene gas main.jpg|thumb|upright|[[Polyethylene]] plastic [[Gas main|main]] being placed in a [[trench]]]]
[[File:Gas underpipe warning notice.jpg|thumb| Construction close to high pressure gas transmission pipelines is discouraged, often with standing warning signs.<ref>{{Cite web |last=[[Ervia#Gas Networks Ireland|Gas Networks Ireland]] |date=2016-06-01 |title=Advice for Working in the Vicinity of Gas Pipelines |url=https://www.gasnetworks.ie/home/gas-meter/meter-services/Safety-Advice-for-Working-in-the-Vicinity-of-Natural-Gas-Pipeline.pdf |access-date=2020-06-20}}</ref>]]{{Update section|date=May 2022|reason=change in transport from Russia}}
Because of its low density, it is not easy to store natural gas or to transport it by vehicle. Natural gas [[pipeline transport|pipelines]] are impractical across oceans, since the gas needs to be cooled down and compressed, as the friction in the pipeline causes the gas to heat up. Many [[List of natural gas pipelines#North America|existing pipelines in the US]] are close to reaching their capacity, prompting some politicians representing northern states to speak of potential shortages. The large trade cost implies that natural gas markets are globally much less integrated, causing significant price differences across countries. In [[Western Europe]], the gas pipeline network is already dense.<ref>{{Cite web |title=Gas Infrastructure Europe |url=http://www.gie.eu.com/ |url-status=dead |archive-url=https://web.archive.org/web/20090830051945/http://www.gie.eu.com/ |archive-date=2009-08-30 |access-date=2009-06-18 |website=Energia Mexicana |language=es}}</ref>{{better source needed|date=November 2017}}{{full citation needed|date=November 2017}} New pipelines are planned or under construction between Western Europe and the [[Near East]] or [[Northern Africa]].<ref>{{Cite web |date=2022-06-23 |title=African gas pipeline projects revived due to European gas crisis |url=https://intellinews.com/african-gas-pipeline-projects-revived-due-to-european-gas-crisis-248456/ |access-date=2023-04-22 |website=intellinews.com |language=en}}</ref>

Whenever gas is bought or sold at custody transfer points, rules and agreements are made regarding the gas quality. These may include the maximum allowable concentration of [[Carbon dioxide|{{chem|C|O|2}}]], [[Hydrogen sulfide|{{chem|H|2|S}}]] and [[Water vapor|{{chem|H|2|O}}]]. Usually sales quality gas that has been [[Natural-gas processing|treated to remove contamination]] is traded on a "dry gas" basis and is required to be commercially free from objectionable odours, materials, and dust or other solid or liquid matter, waxes, gums and gum forming constituents, which might damage or adversely affect operation of equipment downstream of the custody transfer point.

Based on their geographic origin, H-gas (high-calorific gas) and L-gas (low-calorific gas) are to be distinguished.<ref>{{Cite web |last=PowerUP |first=Team |date=2023-10-24 |title=Natural gas – everything you need to know - PowerUp – Parts for Gas-engines |url=https://www.powerup.at/knowledge/natural-gas/natural-gas/ |access-date=2024-12-05 |language=en-US}}</ref> Both types require separate transport, leading to two separate pipeline networks, e.g. in parts of Germany (with a strengthened focus and transition towards H-gas, as the L-gas reservoirs in Germany and the Netherlands are declining).<ref>{{Cite web |date=2024-11-28 |title=Von L-Gas auf H-Gas: Darum wird das Erdgas umgestellt {{!}} Verbraucherzentrale.de |url=https://www.verbraucherzentrale.de/wissen/energie/heizen-und-warmwasser/von-lgas-auf-hgas-darum-wird-das-erdgas-umgestellt-13264 |access-date=2024-12-05 |website=www.verbraucherzentrale.de |language=de}}</ref>

[[LNG carrier]] ships transport [[liquefied natural gas]] (LNG) across oceans, while [[tank truck]]s can carry LNG or compressed natural gas (CNG) over shorter distances.<ref>{{Cite journal |last1=Ulvestad |first1=Marte |last2=Overland |first2=Indra |date=2012 |title=Natural gas and CO2 price variation: Impact on the relative cost-efficiency of LNG and pipelines |journal=International Journal of Environmental Studies |volume=69 |issue=3 |pages=407–426 |doi=10.1080/00207233.2012.677581 |pmc=3962073 |pmid=24683269|bibcode=2012IJEnS..69..407U }}</ref> Sea transport using [[CNG carrier]] ships that are now under development may be competitive with LNG transport in specific conditions.<ref>{{Cite journal |last=Bortnowska |first=Monika |title=Development of new technologies for shipping natural gas by sea |date=2009 |journal=Polish Maritime Research |volume=16 |issue=3/2009 |pages=70–78|doi=10.2478/v10012-008-0036-2 |bibcode=2009PMRes..16c..70B |doi-access=free }}</ref>

Gas is turned into liquid at a [[liquefaction of gases|liquefaction]] plant, and is returned to gas form at [[gasification|regasification]] plant at the [[Liquefied natural gas terminal|terminal]]. Shipborne regasification equipment is also used. LNG is the preferred form for long distance, high volume transportation of natural gas, whereas pipeline is preferred for transport for distances up to {{convert|4000|km|abbr=on}} over land and approximately half that distance offshore.

[[CNG]] is transported at high pressure, typically above {{convert|200|bar|kPa psi|lk=in}}. Compressors and decompression equipment are less capital intensive and may be economical in smaller unit sizes than liquefaction/regasification plants. Natural gas trucks and carriers may transport natural gas directly to end-users, or to distribution points such as pipelines.

[[File:Manlove gas storage facility crop.jpg|thumb|[[Peoples Gas]] Manlove Field [[natural gas storage]] area in [[Newcomb Township, Champaign County, Illinois]]. In the foreground (left) is one of the numerous wells for the underground storage area, with an LNG plant, and above-ground storage tanks are in the background (right).]]

In the past, the natural gas which was recovered in the course of recovering [[petroleum]] could not be profitably sold, and was simply burned at the oil field in a process known as [[gas flare|flaring]]. Flaring is now illegal in many countries.<ref>{{Cite book |last=Hyne |first=Norman J. |url=https://books.google.com/books?id=6CQKozxTKG4C |title=Dictionary of Petroleum Exploration, Drilling & Production |publisher=PennWell Books |year=1991 |isbn=978-0-87814-352-8 |page=190}}</ref> Additionally, higher demand in the last 20–30 years has made production of gas associated with oil economically viable. As a further option, the gas is now sometimes re-[[wikt:inject|injected]] into the formation for [[enhanced oil recovery]] by pressure maintenance as well as miscible or immiscible flooding. Conservation, re-injection, or flaring of natural gas associated with oil is primarily dependent on proximity to markets (pipelines), and regulatory restrictions.

Natural gas can be indirectly exported through the absorption in other physical output. The expansion of shale gas production in the US has caused prices to drop relative to other countries. This has caused a boom in energy intensive manufacturing sector exports, whereby the average dollar unit of US manufacturing exports has almost tripled its energy content between 1996 and 2012.<ref>{{Cite journal |last1=Arezki |first1=Rabah |last2=Fetzer |first2=Thiemo |date=January 2016 |title=On the Comparative Advantage of U.S. Manufacturing: Evidence from the Shale Gas Revolution |url=http://cep.lse.ac.uk/pubs/download/dp1399.pdf |journal=Journal of International Economics |publisher=Centre for Economic Performance |issn=2042-2695 |archive-url=https://web.archive.org/web/20160701075547/http://cep.lse.ac.uk/pubs/download/dp1399.pdf |archive-date=2016-07-01}}</ref>

A "master gas system" was invented in [[Saudi Arabia]] in the late 1970s, ending any necessity for flaring. Satellite and nearby infra-red camera observations, however, shows that flaring<ref>{{Cite web |date=2007-08-29 |title=Bank-Led Satellite Imagery Sheds More Light on Gas Flaring Pollution |url=http://go.worldbank.org/W33BPE31S0 |access-date=2017-11-24 |website=The World Bank – News & Broadcast}}</ref><ref>{{Cite web |last=Ethan |date=2007-11-09 |title=Will eyes in the sky end natural gas flaring? |url=http://www.ethanzuckerman.com/blog/2007/11/09/will-eyes-in-the-sky-end-natural-gas-flaring/ |access-date=2017-11-24 |website=Ethan Zuckerman's online home}}</ref><ref>{{Cite web |date=2007-11-09 |title=Composite image of gas flares in 1992, 2000 and 2006 by NGDC |url=http://www.ethanzuckerman.com/blog/wp-content/2007/11/flares.jpg |access-date=2011-02-06 |website=Ethan Zuckerman's online home}} [https://www.ngdc.noaa.gov/ National Geophysical Data Center (NGDC)]</ref><ref>{{Cite web |title=Composite image of the earth at night |url=https://nssdc.gsfc.nasa.gov/planetary/image/earth_night.jpg |access-date=2017-11-24 |via=Ethan Zuckerman's online home}}</ref> and venting<ref>{{Cite news |last1=Abnett |first1=Kate |last2=Nasralla |first2=Shadia |date=2021-06-24 |title=Gas infrastructure across Europe leaking planet-warming methane |language=en |work=Reuters |url=https://www.reuters.com/business/environment/exclusive-gas-infrastructure-across-europe-leaking-planet-warming-methane-video-2021-06-24/ |access-date=2021-12-18}}</ref> are still happening in some countries.

Natural gas is used to generate electricity and heat for [[desalination]]. Similarly, some landfills that also discharge methane gases have been set up to capture the methane and generate electricity.

Natural gas is often stored underground [references about geological storage needed]inside depleted gas reservoirs from previous gas wells, [[salt domes]], or in tanks as liquefied natural gas. The gas is injected in a time of low demand and extracted when demand picks up. Storage nearby end users helps to meet volatile demands, but such storage may not always be practicable.

With 15 countries accounting for 84% of the worldwide extraction, access to natural gas has become an important issue in international politics, and countries vie for control of pipelines.<ref>{{Cite web |last=Jürgen Wagner |date=2007-06-19 |title=The Contours of the New Cold War |url=http://www.imi-online.de/2007/06/19/thecontoursofthe/ |access-date=2011-02-06 |publisher=IMI}}</ref> In the first decade of the 21st century, [[Gazprom]], the state-owned energy company in Russia, engaged in disputes with [[Ukraine]] and [[Belarus]] over the price of natural gas, which have created concerns that gas deliveries to parts of Europe could be cut off for political reasons.<ref>{{Cite web |title=Gazprom and Russian Foreign Policy |url=<!--http://www.npr.org/templates/story/story.php?storyId=99026745-->https://www.npr.org/series/99026745/gazprom-and-russia-s-foreign-policy |access-date=<!--2011-02-06-->2017-11-24 |website=NPR}}</ref> The United States is preparing to export natural gas.<ref>{{Cite web |last=Sumit Roy |date=2014-06-23 |title=U.S. Natural Gas Export Era Begins In 2015, Fueling Upside In Prices |url=http://seekingalpha.com/article/2282733-u-s-natural-gas-export-era-begins-in-2015-fueling-upside-in-prices |access-date=2015-06-11 |website=Seeking Alpha}}</ref>

===Floating liquefied natural gas===
[[Floating liquefied natural gas]] (FLNG) is an innovative technology designed to enable the development of offshore gas resources that would otherwise remain untapped due to environmental or economic factors which currently make them impractical to develop via a land-based LNG operation. FLNG technology also provides a number of environmental and economic advantages:
* Environmental&nbsp;– Because all processing is done at the gas field, there is no requirement for long pipelines to shore, compression units to pump the gas to shore, dredging and jetty construction, and onshore construction of an LNG processing plant, which significantly reduces the environmental footprint.<ref>{{Cite web |title=SEAAOC – NT Resources Week – Informa – NT Government |url=http://www.seaaoc.com/news-old/shell-receives-green-light-for-prelude-flng |url-status=dead |archive-url=https://web.archive.org/web/20120325160619/http://www.seaaoc.com/news-old/shell-receives-green-light-for-prelude-flng |archive-date=2012-03-25 |access-date=2015-06-11 |website=NTRW}}</ref> Avoiding construction also helps preserve marine and coastal environments. In addition, environmental disturbance will be minimised during decommissioning because the facility can easily be disconnected and removed before being refurbished and re-deployed elsewhere.
* Economic&nbsp;– Where pumping gas to shore can be prohibitively expensive, FLNG makes development economically viable. As a result, it will open up new business opportunities for countries to develop offshore gas fields that would otherwise remain stranded, such as those offshore East Africa.<ref>{{Cite web |date=2011-01-28 |title=The Floating Liquefied Natural Gas (FLNG) Market 2011-2021 |url=http://www.visiongain.com/Report/568/The-Floating-Liquefied-Natural-Gas-(FLNG)-Market-2011-2021 |url-access=subscription |url-status=dead |archive-url=https://web.archive.org/web/20150319155339/https://www.visiongain.com/Report/568/The-Floating-Liquefied-Natural-Gas-(FLNG)-Market-2011-2021 |archive-date=2015-03-19 |access-date=2015-06-11 |website=visiongain |id=ENE8974}}</ref>

Many gas and oil companies are considering the economic and environmental benefits of floating liquefied natural gas (FLNG). There are currently projects underway to construct five FLNG facilities. [[Petronas]] is close to completion on their FLNG-1<ref>{{Cite web |date=2015-04-22 |title=Petronas' FLNG Facility to Deliver First Cargo in Q1 2016 |url=http://worldmaritimenews.com/archives/158677/petronas-flng-facility-to-deliver-first-cargo-in-q1-2016/ |access-date=2017-11-23 |website=World Maritime News Staff}}</ref> at [[Daewoo Shipbuilding and Marine Engineering]] and are underway on their FLNG-2 project<ref>{{Cite web |last=Raj |first=Audrey |date=2015-06-16 |title=Steel cut for PETRONAS FLNG 2 |url=http://www.aogdigital.com/component/k2/item/4971-steel-cut-for-petronas-flng-2 |access-date=2017-11-23 |website=Asian Oil & Gas}}</ref> at [[Samsung Heavy Industries]]. [[Shell Prelude]] is due to start production 2017.<ref>{{Cite web |title=prelude starts production |url=https://www.shell.com/media/news-and-media-releases/2017/prelude-arrives-in-australia.html}}</ref> The [[Browse LNG]] project will commence [[Front-end loading|FEED]] in 2019.<ref>{{Cite web |title=Browse Development – We remain committed to the earliest commercial development of the world-class Browse resources |url=http://www.woodside.com.au/Our-Business/Developing/Browse/Pages/Browse.aspx#.WhjzruNFyUl |website=www.woodside.com.au |quote=Woodside continues to target the selection of a Browse development concept in H2 2017 and commencement of front-end engineering and design (FEED) in 2019.}}</ref>

==Uses==

Natural gas is primarily used in the northern hemisphere. North America and Europe are major consumers.

Often well head gases require removal of various hydrocarbon molecules contained within the gas. Some of these gases include [[heptane]], [[pentane]], [[propane]] and other hydrocarbons with molecular weights above [[methane]] ({{chem|C|H|4}}). The natural gas transmission lines extend to the natural gas processing plant or unit which removes the higher-molecular weight hydrocarbons to produce natural gas with energy content between {{convert|950|-|1050|BTU/cuft|MJ/m3|order=flip|abbr=off}}. The processed natural gas may then be used for residential, commercial and industrial uses.

===Mid-stream natural gas===
Natural gas flowing in the distribution lines is called mid-stream natural gas and is often used to power engines which rotate compressors. These compressors are required in the transmission line to pressurize and repressurize the mid-stream natural gas as the gas travels. Typically, natural gas powered engines require {{convert|950|-|1050|BTU/cuft|MJ/m3|abbr=on|order=flip}} natural gas to operate at the rotational name plate specifications.<ref name="american-environmental">{{Cite web |title=Natural Gas Fuel Conditioning System – BTU Reduction |url=http://rto.american-environmental.us/BTU_Reduction_and_Gas_Conditioning_System.html |url-status=dead |archive-url=https://web.archive.org/web/20171207152113/http://rto.american-environmental.us/BTU_Reduction_and_Gas_Conditioning_System.html |archive-date=2017-12-07 |access-date=2017-11-23 |website=American Environmental Fabrication & Supply, LLC}}</ref> Several methods are used to remove these higher molecular weighted gases for use by the natural gas engine. A few technologies are as follows:
* [[Joule–Thomson effect|Joule–Thomson skid]]
* [[Cryogenic]] or [[chiller]] system
* [[Chemical]] [[enzymology]] system<ref name="american-environmental" />

===Power generation===
{{Excerpt|Gas-fired power plant}}

===Domestic use===
[[File:GAS GAS manhole cover London.jpg|thumb|right|Manhole for domestic gas supply, London, UK]]
In the US, over one-third of households (>40 million homes) cook with gas.<ref name="Kashtan-2023" /> Natural gas dispensed in a residential setting can generate temperatures in excess of {{convert|1100|°C|°F|-2}} making it a powerful domestic cooking and heating fuel.<ref>{{Cite book |last1=Zimmerman |first1=Barry E. |url=https://archive.org/details/naturescuriosity00zimm/page/28 |title=Nature's Curiosity Shop |last2=Zimmerman |first2=David J. |publisher=Contemporary books |year=1995 |isbn=978-0-8092-3656-5 |location=Lincolnwood (Chicago), IL |page=[https://archive.org/details/naturescuriosity00zimm/page/28 28] |url-access=registration}}</ref> Stanford scientists estimated that gas stoves emit 0.8–1.3% of the gas they use as unburned methane and that total U.S. stove emissions are 28.1 gigagrams of methane.<ref name="Kashtan-2023" /> In much of the developed world it is supplied through pipes to homes, where it is used for many purposes including ranges and ovens, [[HVAC|heating]]/[[air conditioning|cooling]], outdoor and portable [[Grilling|grills]], and [[central heating]].<ref name="AtoZ">{{Cite book |last=Mulvaney |first=Dustin |url=https://books.google.com/books?id=Z_eji4ZzEiQC&pg=PA301 |title=Green Energy: An A-to-Z Guide |date=2011 |publisher=SAGE |isbn=978-1-4129-9677-8 |page=301}}</ref> Heaters in homes and other buildings may include boilers, [[Furnace (house heating)|furnace]]s, and [[water heating|water heaters]]. Both North America and Europe are major consumers of natural gas.

Domestic appliances, furnaces, and boilers use low pressure, usually with a standard pressure around {{convert|0.25|psi|kPa|order=flip}} over atmospheric pressure. The pressures in the supply lines vary, either the standard utilization pressure (UP) mentioned above or elevated pressure (EP), which may be anywhere from {{convert|1|to|120|psi|kPa|order=flip|sigfig=1}} over atmospheric pressure. Systems using EP have a [[pressure regulator|regulator]] at the service entrance to step down to UP.<ref>{{Cite web |date=2017-04-03 |title=Using 2PSI Elevated Pressure Natural Gas Technology to Help Reduce Costs in Next- Generation Multi-Family New Construction |url=https://abcgreenhome.com/2017/04/03/using-2psi-elevated-pressure-natural-gas-technology-help-reduce-costs-next-generation-multi-family-new-construction/ |access-date=2023-04-22 |website=The ABC Green Home Project |language=en-US}}</ref>

Natural gas piping systems inside buildings are often designed with pressures of {{convert|2|to|5|psi|kPa|order=flip}}, and have downstream pressure regulators to reduce pressure as needed. In the United States the maximum allowable operating pressure for natural gas piping systems within a building is based on NFPA 54: National Fuel Gas Code,<ref>{{Cite web |title=NFPA 54: National Fuel Gas Code |url=https://www.nfpa.org/codes-and-standards/all-codes-and-standards/list-of-codes-and-standards/detail?code=54 |access-date=2023-04-22 |website=www.nfpa.org}}</ref> except when approved by the Public Safety Authority or when insurance companies have more stringent requirements.

Generally, natural gas system pressures are not allowed to exceed {{convert|5|psi|kPa|abbr=on}} unless all of the following conditions are met:
* The AHJ will allow a higher pressure.
* The distribution pipe is welded. (Note: 2. Some jurisdictions may also require that welded joints be radiographed to verify continuity).
* The pipes are closed for protection and placed in a ventilated area that does not allow gas accumulation.
* The pipe is installed in the areas used for industrial processes, research, storage or mechanical equipment rooms.

Generally, a maximum liquefied petroleum gas pressure of {{convert|20|psi|kPa|abbr=on}} is allowed, provided the building is constructed in accordance with NFPA 58: Liquefied Petroleum Gas Code, Chapter 7.<ref>[https://www.mepengineerings.com/wp-content/uploads/2020/10/plumbing-engineering-design-handbook-vol-2-2010.pdf] Plumbing Engineering Design Handbook | A Plumbing Engineer's Guide to System Design and Specifications | American Society of Plumbing Engineers | Plumbing Systems | Volume 2 Chapter 7 — Fuel Gas Piping Systems Page 115</ref>

A seismic earthquake valve operating at a pressure of 55 psig (3.7 bar) can stop the flow of natural gas into the site wide natural gas distribution piping network (that runs (outdoors underground, above building roofs, and or within the upper supports of a canopy roof). Seismic earthquake valves are designed for use at a maximum of 60 psig.<ref>[https://repositorio-aberto.up.pt/bitstream/10216/95430/2/142685.pdf] Risk-based maintenance: an holistic application to the gas distribution industry | Xavier António Reis Andrade | 2016 | Page 15 | Figure 3.2: Technical drawing of the pressure regulator and measurement station.</ref><ref>[https://www.dgs.ca.gov/DSA/Services/Page-Content/Division-of-the-State-Architect-Services-List/Apply-for-Gas-Shutoff-Valve-Certification-for-Residential-Structures]  State of California | Apply for Gas Shutoff Valve Certification for Residential Structures | The Division of the State Architect (DSA) oversees the certification of two types of gas shutoff valves as required by the Health and Safety Code.</ref>

In Australia, natural gas is transported from gas processing facilities to regulator stations via transmission pipelines. Gas is then regulated down to distributed pressures and the gas is distributed around a gas network via gas mains. Small branches from the network, called services, connect individual domestic dwellings, or multi-dwelling buildings to the network. The networks typically range in pressures from 7 kPa (low pressure) to 515 kPa (high pressure). Gas is then regulated down to 1.1 kPa or 2.75 kPa, before being metered and passed to the consumer for domestic use.<ref>{{Cite web |title=Gas Distribution System Code {{!}} Essential Services Commission |url=https://www.esc.vic.gov.au/electricity-and-gas/codes-guidelines-and-policies/gas-distribution-system-code |access-date=2020-09-22 |website=www.esc.vic.gov.au}}</ref> Natural gas mains are made from a variety of materials: historically cast iron, though more modern mains are made from steel or polyethylene.

In some states in the USA, natural gas can be supplied by independent natural gas wholesalers/suppliers using existing pipeline owners' infrastructure through [[Natural Gas Choice]] programs.

LPG ([[liquefied petroleum gas]]) typically fuels outdoor and portable [[Grill (cooking)|grills]]. Although, [[compressed natural gas]] (CNG) is sparsely available for similar applications in the US in [[rural]] areas underserved by the existing pipeline system and distribution network of the less expensive and more abundant LPG ([[liquefied petroleum gas]]).
[[File:Bus natural gas in Salamanca.JPG|thumb|Natural gas bus in [[Salamanca]], Spain]]

===Transportation===
[[File:2009 Honda Civic NGV--DC.jpg|thumb|[[Honda Civic GX]], a natural gas-powered automobile sold in North America from 1998 to 2015]]
CNG is a cleaner and also cheaper alternative to other [[automobile]] fuels such as [[gasoline]] (petrol).<ref>{{Cite web |title=Alternative Fuels Data Center: Natural Gas Vehicle Emissions |url=https://afdc.energy.gov/vehicles/natural_gas_emissions.html |access-date=2019-09-01 |website=afdc.energy.gov}}</ref> By the end of 2014, there were over 20&nbsp;million [[natural gas vehicles]] worldwide, led by [[Iran]] (3.5&nbsp;million), [[China]] (3.3&nbsp;million), [[Pakistan]] (2.8&nbsp;million), [[Argentina]] (2.5&nbsp;million), [[India]] (1.8&nbsp;million), and [[Brazil]] (1.8&nbsp;million).<ref>{{Cite web |title=Worldwide NGV statistics |url=http://www.ngvjournal.com/worldwide-ngv-statistics/ |archive-url=https://web.archive.org/web/20150206153839/http://www.ngvjournal.com/worldwide-ngv-statistics/ |archive-date=2015-02-06 |access-date=2017-11-19 |website=NGV journal}}</ref> The [[Efficient energy use|energy efficiency]] is generally equal to that of gasoline engines, but lower compared with modern diesel engines. Gasoline/petrol vehicles converted to run on natural gas suffer because of the low [[compression ratio]] of their engines, resulting in a cropping of delivered power while running on natural gas (10–15%). CNG-specific engines, however, use a higher compression ratio due to this fuel's higher [[octane number]] of 120–130.<ref>{{Cite web |date=2010-10-22 |title=Clean Engine Vehicle |url=http://www.idsc.ethz.ch/Research_Guzzella/Automotive_Applications/CNG_Engines/Archives/Clean_Engine_Vehicle |archive-url=https://web.archive.org/web/20150124010702/http://www.idsc.ethz.ch/Research_Guzzella/Automotive_Applications/CNG_Engines/Archives/Clean_Engine_Vehicle |archive-date=2015-01-24 |access-date=2015-01-23 |website=ETH Zurich}}</ref>

Besides use in road vehicles, CNG can also be used in aircraft.<ref>{{Cite news |date=2014-11-06 |title=Take a look at some natural gas-powered airplanes |work=Well Said |url=http://wellsaidcabot.com/cng-vehicles-airplanes/}}</ref> Compressed natural gas has been used in some aircraft like the [[Aviat Aircraft]] Husky 200 CNG<ref>{{Cite magazine |last=Jason Paur |date=2013-07-31 |title=American Firm Debuts First Airplane to Run on Natural Gas |url=https://www.wired.com/2013/07/cng-airplane/ |magazine=Wired}}</ref> and the Chromarat VX-1 KittyHawk<ref>{{Cite web |last=Le Cheylard France |date=2014-02-19 |title=Chomarat Present C-Ply KittyHawk with CNG Potential |url=http://www.ngvglobal.com/blog/chomarat-present-c-ply-kittyhawk-with-cng-potential-0219 |archive-url=https://web.archive.org/web/20171201035743/http://www.ngvglobal.com/blog/chomarat-present-c-ply-kittyhawk-with-cng-potential-0219 |url-status=usurped |archive-date=1 December 2017 |website=NGV Global News}}</ref>

LNG is also being used in aircraft. [[Russia]]n aircraft manufacturer [[Tupolev]] for instance is running a development program to produce LNG- and [[hydrogen]]-powered aircraft.<ref>{{Cite web |title=Development of Cryogenic Fuel Aircraft |url=http://www.tupolev.ru/English/Show.asp?SectionID=82&Page=1 |url-status=dead |archive-url=https://web.archive.org/web/20101209165256/http://www.tupolev.ru/English/Show.asp?SectionID=82&Page=1 |archive-date=2010-12-09 |access-date=2011-02-06 |publisher=Tupolev}}</ref> The program has been running since the mid-1970s, and seeks to develop LNG and hydrogen variants of the [[Tupolev Tu-204|Tu-204]] and [[Tupolev Tu-334|Tu-334]] passenger aircraft, and also the [[Tupolev Tu-330|Tu-330]] cargo aircraft. Depending on the current market price for jet fuel and LNG, the consumption cost advantage for LNG-powered aircraft is approximately 18.96%, along with a 53.72% reduction to [[carbon monoxide]], [[hydrocarbon]] and [[nitrogen oxide]] emissions.<ref>Sogut, M.Z. (2023). Examining Thermo-Economic and Environmental Performance of Piston Engine Considering LNG Fuel Transition of Aircraft. In: Karakoc, T.H., Atipan, S., Dalkiran, A., Ercan, A.H., Kongsamutr, N., Sripawadkul, V. (eds) Research Developments in Sustainable Aviation. Springer, Cham. https://doi.org/10.1007/978-3-031-37943-7_30</ref>


The advantages of liquid methane as a jet engine fuel are that it has more [[specific energy]] than the standard [[kerosene]] mixes do and that its low temperature can help cool the air which the engine compresses for greater volumetric efficiency, in effect replacing an [[intercooler]]. Alternatively, it can be used to lower the temperature of the exhaust.{{Citation needed|date=October 2022}}

===Fertilizers===
{{See also|2007–2008 world food price crisis}}
Natural gas is a major feedstock for the production of [[ammonia]], via the [[Haber process]], for use in [[fertilizer]] production.<ref name=AtoZ/><ref>{{Cite news |date=2022-05-06 |title=Soaring fertilizer prices put global food security at risk |work=Axios |url=https://www.axios.com/2022/05/06/fertilizer-prices-food-securtiy}}</ref> The development of synthetic nitrogen fertilizer has significantly supported global [[population growth]]&nbsp;— it has been estimated that almost half the people on the Earth are currently fed as a result of synthetic nitrogen fertilizer use.<ref>{{Cite journal |last1=Erisman |first1=Jan Willem |first2=MA |last2=Sutton |first3=J |last3=Galloway |first4=Z |last4=Klimont |first5=W |last5=Winiwarter |date=October 2008 |title=How a century of ammonia synthesis changed the world |url=http://www.physics.ohio-state.edu/~wilkins/energy/Resources/Essays/ngeo325.pdf.xpdf |url-status=dead |journal=[[Nature Geoscience]] |volume=1 |issue=10 |pages=636–639 |bibcode=2008NatGe...1..636E |doi=10.1038/ngeo325 |archive-url=https://web.archive.org/web/20100723223052/http://www.physics.ohio-state.edu/~wilkins/energy/Resources/Essays/ngeo325.pdf.xpdf |archive-date=2010-07-23 |s2cid=94880859}}</ref><ref>{{Cite news |date=2021-10-20 |title=Fears global energy crisis could lead to famine in vulnerable countries |work=The Guardian |url=https://www.theguardian.com/business/2021/oct/20/global-energy-crisis-famine-production}}</ref>

===Hydrogen===
{{See also|Industrial gas}}

Natural gas can be used to produce [[hydrogen]], with one common method being the [[hydrogen reformer]]. Hydrogen has many applications: it is a primary feedstock for the [[chemical industry]], a hydrogenating agent, an important commodity for oil refineries, and the fuel source in [[hydrogen vehicle]]s.

===Animal and fish feed===
Protein rich animal and fish feed is produced by feeding natural gas to [[Methylococcus capsulatus]] bacteria on commercial scale.<ref>{{Cite web |title=BioProtein Production |url=https://www.ntva.no/wp-content/uploads/2014/01/04-huslid.pdf |url-status=dead |archive-url=https://web.archive.org/web/20170510151825/http://www.ntva.no/wp-content/uploads/2014/01/04-huslid.pdf |archive-date=2017-05-10 |access-date=2018-01-31}}</ref><ref>{{Cite web |title=Food made from natural gas will soon feed farm animals – and us |url=https://www.newscientist.com/article/2112298-food-made-from-natural-gas-will-soon-feed-farm-animals-and-us/ |access-date=2018-01-31}}</ref><ref>{{Cite web |title=New venture selects Cargill's Tennessee site to produce Calysta FeedKind® Protein |url=https://www.cargill.com/2016/new-venture-selects-cargill-tennessee-to-produce-feedkind |access-date=2018-01-31}}</ref>

=== Olefins(alkenes) ===
Natural gas components(alkanes) can be converted into [[Olefins|olefins(alkenes)]] or other [[chemical synthesis]]. Ethane by oxidative dehydrogenation converts to ethylene, which can be further converted to [[ethylene oxide]], [[ethylene glycol]], [[acetaldehyde]] or other olefins. Propane by oxidative hydrogenation converts to propylene or can be oxidized to acrylic acid and [[acrylonitrile]].

===Other===
Natural gas is also used in the manufacture of [[textile|fabrics]], [[glass]], [[steel]], [[plastic]]s, [[paint]], [[synthetic oil]], and other products.<ref>{{Cite news |last=Le Page |first=Michael |date=2016-11-10 |title=Food made from natural gas will soon feed farm animals – and us |work=New Scientist |url=https://www.newscientist.com/article/2112298-food-made-from-natural-gas-will-soon-feed-farm-animals-and-us/ |access-date=2016-12-13}}</ref>

Fuel for industrial heating and [[desiccation]] processes.

Raw material for large-scale fuel production using [[gas-to-liquid]] (GTL) process (e.g. to produce sulphur-and aromatic-free diesel with low-emission combustion).

== Health effects ==
Cooking with natural gas contributes to poor [[indoor air quality]] and can lead to severe respiratory diseases such as [[asthma]].<ref name="CLASP-2023">{{Cite web |date=8 November 2023 |title=Clearing the Air: Gas Cooking and Pollution in European Homes |url=https://www.clasp.ngo/research/all/cooking-with-gas-findings-from-a-pan-european-indoor-air-quality-field-study/ |access-date=2024-05-05 |website=CLASP |language=en}}</ref><ref name="Seals">{{Cite web |last1=Seals |first1=Brady |last2=Krasner |first2=Andee |title=Gas Stoves: Health and Air Quality Impacts and Solutions |url=https://rmi.org/insight/gas-stoves-pollution-health/ |access-date=2024-05-05 |website=RMI |language=en-US}}</ref>

==Environmental effects==
[[File:2021 Death rates, by energy source.svg |thumb|upright=1.35 |Deaths caused by use of fossil fuels such as natural gas (areas of rectangles in chart) greatly exceed those resulting from production of [[wind energy]], [[Nuclear power|nuclear energy]] or [[solar energy]] (rectangles barely visible in chart).<ref name=OWID_SafestEnergy_2021>{{cite journal |last1=Ritchie |first1=Hannah |last2=Roser |first2=Max |title=What are the safest and cleanest sources of energy? |url=https://ourworldindata.org/safest-sources-of-energy |journal=Our World in Data |archive-url=https://web.archive.org/web/20240115112316/https://ourworldindata.org/safest-sources-of-energy |archive-date=15 January 2024 |date=2021 |url-status=live }} Data sources: Markandya & Wilkinson (2007); UNSCEAR (2008; 2018); Sovacool et al. (2016); IPCC AR5 (2014); Pehl et al. (2017); Ember Energy (2021).</ref>]]

{{See also|Environmental impact of the energy industry}}

===Greenhouse effect and natural gas release===
{{See also|Greenhouse effect|Atmospheric methane|Gas venting|Fugitive gas emissions}}
[[File:1979- Radiative forcing - climate change - global warming - EPA NOAA.svg|thumb|upright=1.35 | The warming influence (called [[radiative forcing]]) of long-lived greenhouse gases has increased substantially in the last 40 years, with carbon dioxide and methane being the dominant drivers of global warming.<ref name=NOAA_AGGI_2023>{{cite web |title=The NOAA Annual Greenhouse Gas Index (AGGI) |url=https://gml.noaa.gov/aggi/aggi.html |website=NOAA.gov |publisher=National Oceanic and Atmospheric Administration (NOAA) |archive-url=https://web.archive.org/web/20241005195609/https://gml.noaa.gov/aggi/aggi.html |archive-date=5 October 2024 |date=2024 |url-status=live }}</ref>]]
Natural gas is a growing contributor to [[climate change]].<ref>{{Cite news |last1=Valerie Volcovici |last2=Kate Abnett |last3=Matthew Green |date=2020-08-18 |title=Cleaner but not clean - Why scientists say natural gas won't avert climate disaster |work=Reuters |url=https://www.reuters.com/article/us-usa-gas-climatebox-explainer-idUSKCN25E1DR}}</ref><ref name="ieaco2">{{Cite web |title=Data and Statistics: CO2 emissions by energy source, World 1990-2017 |url=https://www.iea.org/data-and-statistics?country=WORLD&fuel=CO2%20emissions&indicator=CO2%20emissions%20by%20energy%20source |access-date=2020-04-24 |publisher=International Energy Agency (Paris)}}</ref><ref name="owidebf">{{Cite journal |author=Hannah Ritchie |author-link=Hannah Ritchie | author2=Max Roser |author2-link=Max Roser |year=2020 |title=CO₂ and Greenhouse Gas Emissions: CO₂ Emissions by Fuel |url=https://ourworldindata.org/co2-and-other-greenhouse-gas-emissions#co2-emissions-by-fuel |journal=Our World in Data |publisher=Published online at OurWorldInData.org. |access-date=2020-04-24}}</ref>  Both the NG itself (specifically [[Methane emissions|methane]]) and [[Carbon dioxide in Earth's atmosphere|carbon dioxide]], which is released when natural gas is burned, are [[greenhouse gas]]es.<ref>{{Cite web |date=2020-07-27 |title=Why carbon dioxide isn't the only greenhouse gas we must reduce – Dr Richard Dixon |url=https://www.scotsman.com/news/opinion/columnists/climate-change-carbon-dioxide-main-greenhouse-gas-cutting-methane-emissions-crucial-too-dr-richard-dixon-2925261 |access-date=2020-08-17 |website=www.scotsman.com |language=en}}</ref><ref name="AGI">{{Cite web |date=2018-05-16 |title=Methane Emissions in the Oil and Gas Industry |url=https://www.americangeosciences.org/critical-issues/factsheet/pe/methane-emissions-oil-gas-industry |access-date=2019-05-01 |publisher=American Geosciences Institute}}</ref>
Human activity is responsible for about 60% of all [[methane emissions]] and for most of the resulting increase in atmospheric methane.<ref name="nationalgeo">{{Cite web |date=2019-01-23 |title=Methane, explained |url=https://www.nationalgeographic.com/environment/global-warming/methane/ |archive-url=https://web.archive.org/web/20190417010815/https://www.nationalgeographic.com/environment/global-warming/methane/ |url-status=dead |archive-date=17 April 2019 |access-date=2020-04-24 |website=National Geographic |publisher=nationalgeographic.com}}</ref><ref>{{Cite web |title=Global Carbon Project (GCP) |url=https://www.globalcarbonproject.org/methanebudget/index.htm |access-date=2020-04-24 |website=www.globalcarbonproject.org |language=en}}</ref><ref name="IPCC_AR5">Myhre, G., D. Shindell, F.-M. Bréon, W. Collins, J. Fuglestvedt, J. Huang, D. Koch, J.-F. Lamarque, D. Lee, B. Mendoza, T. Nakajima, A. Robock, G. Stephens, T. Takemura and H. Zhang (2013) [http://www.climatechange2013.org/images/report/WG1AR5_Chapter08_FINAL.pdf "Anthropogenic and Natural Radiative Forcing"]. Table 8.7 on page 714. In: ''Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change''. Stocker, T.F., D. Qin, G.-K. Plattner, M. Tignor, S.K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex and P.M. Midgley (eds.). Cambridge University Press, Cambridge, United Kingdom and New York, New York, US. [http://www.climatechange2013.org/images/report/WG1AR5_Chapter08_FINAL.pdf Anthropogenic and Natural Radiative Forcing]</ref> Natural gas is intentionally released or is otherwise known to leak during the extraction, storage, transportation, and distribution of [[fossil fuels]]. Globally, methane accounts for an estimated 33% of anthropogenic [[Greenhouse effect|greenhouse gas warming]].<ref name="Initiative">{{Cite web |title=Global Methane Emissions and Mitigation Opportunities |url=https://www.globalmethane.org/documents/gmi-mitigation-factsheet.pdf |access-date=2020-04-24 |publisher=[[Global Methane Initiative]]}}</ref> The decomposition of municipal solid waste (a source of [[landfill gas]]) and wastewater account for an additional 18% of such emissions.   These estimates include substantial uncertainties<ref>{{Cite web |last=Caroline Gramling |date=2020-02-19 |title=Fossil fuel use may emit 40 percent more methane than we thought |url=https://www.sciencenews.org/article/fossil-fuel-use-may-emit-more-methane-than-thought |access-date=2020-04-24 |publisher=Science News}}</ref> which should be reduced in the near future with improved [[Earth observation satellite|satellite]] measurements, such as those planned for [[MethaneSAT]].<ref name=AGI/>

After release to the atmosphere, methane is removed by gradual oxidation to carbon dioxide and water by hydroxyl radicals ({{chem|O|H|-}}) formed in the troposphere or stratosphere, giving the overall chemical reaction {{chem|C|H|4}} + 2{{chem|O|2}} → {{chem|C|O|2}} + 2{{chem|H|2|O}}.<ref name="Manahan">{{Cite book |last=Stanley Manahan |title=Environmental Chemistry |publisher=CRC press |year=2010 |isbn=978-1420059205 |edition=9th}}</ref><ref name="NASA GISS">{{Cite web |last=Gavin Schmidt |date=September 2004 |title=Methane: A Scientific Journey from Obscurity to Climate Super-Stardom |url=http://www.giss.nasa.gov/research/features/200409_methane/ |access-date=2013-06-11 |website=National Aeronautics and Space Administration. Goddard Institute for Space Studies}}</ref> While the lifetime of atmospheric methane is relatively short when compared to carbon dioxide,<ref name="Ny times">{{Cite news |date=2009-10-14 |title=Curbing Emissions by Sealing Gas Leaks |work=The New York Times |url=https://www.nytimes.com/2009/10/15/business/energy-environment/15degrees.html?_r=3&hpw& |access-date=2013-06-11}}</ref> with a [[half-life]] of about 7 years, it is more efficient at trapping heat in the atmosphere, so that a given quantity of methane has 84 times the [[global-warming potential]] of carbon dioxide over a 20-year period and 28 times over a 100-year period. Natural gas is thus a potent greenhouse gas due to the strong [[radiative forcing]] of methane in the short term, and the continuing effects of carbon dioxide in the longer term.<ref name="IPCC_AR5" />

Targeted efforts to reduce warming quickly by reducing anthropogenic methane emissions is a [[climate change mitigation]] strategy supported by the [[Global Methane Initiative]].<ref name="Initiative" />

===Greenhouse gas emissions===
When refined and burned, natural gas can produce 25–30% less carbon dioxide per [[joule]] delivered than oil, and 40–45% less than coal.<ref name="NGandE">{{Cite web |title=Natural Gas and the Environment |url=http://www.naturalgas.org/environment/naturalgas.asp |url-status=dead |archive-url=https://web.archive.org/web/20090503132200/http://www.naturalgas.org/environment/naturalgas.asp |archive-date=2009-05-03 |access-date=2013-06-11 |publisher=NaturalGas.org}}</ref> It can also produce potentially fewer toxic [[pollutant]]s than other hydrocarbon fuels.<ref name=NGandE/><ref name="NGinASIA">{{Cite web |last=Mikkal Herberg |others=(written for 2011 Pacific Energy Summit) |title=Natural Gas in Asia: History and Prospects |url=http://www.nbr.org/downloads/pdfs/eta/PES_2011_Herberg.pdf |website=The National Bureau of Asian Research}}</ref> However, compared to other major fossil fuels, natural gas causes more emissions in relative terms during the production and transportation of the fuel, meaning that the life cycle greenhouse gas emissions are about 50% higher than the direct emissions from the site of consumption.<ref>Cooney et al. (2014): [https://www.energy.gov/fe/downloads/life-cycle-greenhouse-gas-perspective-exporting-liquefied-natural-gas-united-states Life Cycle Greenhouse Gas Perspective on Exporting Liquefied Natural Gas from the United States]. National Energy Technology Laboratory, US Department of Energy.</ref><ref>{{Cite journal |last1=Rosselot |first1=Kirsten S. |last2=Allen |first2=David T. |last3=Ku |first3=Anthony Y. |date=2021-07-05 |title=Comparing Greenhouse Gas Impacts from Domestic Coal and Imported Natural Gas Electricity Generation in China |journal=ACS Sustainable Chemistry & Engineering |language=en |volume=9 |issue=26 |pages=8759–8769 |doi=10.1021/acssuschemeng.1c01517 |issn=2168-0485 |s2cid=237875562|doi-access=free }}</ref>

In terms of the warming effect over 100 years, natural gas production and use comprises about one fifth of human [[greenhouse gas emissions]], and this contribution is growing rapidly. Globally, natural gas use emitted about 7.8&nbsp;billion tons of {{chem|C|O|2}} in 2020 (including flaring), while coal and oil use emitted 14.4 and 12&nbsp;billion tons, respectively.<ref>{{Cite journal |last1=Ritchie |first1=Hannah |last2=Roser |first2=Max |date=2020-05-11 |title=CO2 emissions by fuel |url=https://ourworldindata.org/emissions-by-fuel |journal=Our World in Data |access-date=2021-01-22}}</ref> The IEA estimates the energy sector (oil, natural gas, coal and bioenergy) to be responsible for about 40% of human methane emissions.<ref>{{Cite web |title=Global Methane Tracker 2022 – Analysis |url=https://www.iea.org/reports/global-methane-tracker-2022 |access-date=2022-04-03 |website=IEA |date=23 February 2022 |language=en-GB}}</ref>  According to the [[IPCC Sixth Assessment Report]], natural gas consumption grew by 15% between 2015 and 2019, compared to a 5% increase in oil and oil product consumption.<ref>{{Cite book |last1=Canadell |first1=Josep G. |title={{Harvnb|IPCC AR6 WG1|2021}} |last2=Scheel Monteiro |first2=Pedro |last3=Costa |first3=Marcos H. |last4=Cotrim da Cunha |first4=Leticia |last5=Cox |first5=Peter M. |last6=Eliseev |first6=Alexey V. |last7=Henson |first7=Stephanie |last8=Ishii |first8=Masao |last9=Jaccard |first9=Samuel |year=2021 |chapter=Chapter 5: Global carbon and other biogeochemical cycles and feedbacks |ref={{harvid|IPCC AR6 WG1 Ch5|2021}} |display-authors=4 |chapter-url=https://www.ipcc.ch/report/ar6/wg1/downloads/report/IPCC_AR6_WGI_Chapter_05.pdf |last10=Koven |first10=Charles |last11=Lohila |first11=Annalea |last12=Patra |first12=Prabir K. |last13=Piao |first13=Shilong}}</ref>

The continued financing and construction of new gas [[pipeline transport|pipelines]] indicates that huge emissions of fossil greenhouse gases could be locked-in for 40 to 50 years into the future.<ref name="GEM2019">{{Cite news |date=2019-04-25 |title=North American drilling boom threatens big blow to climate efforts, study finds |work=[[The Guardian]] |url=https://www.theguardian.com/environment/2019/apr/25/us-oil-gas-boom-climate-change-report}}</ref> In the U.S. state of [[Texas]] alone, five new long-distance gas pipelines have been under construction, with the first entering service in 2019,<ref>{{Cite web |date=2019-09-24 |title=Gulf Coast Express Pipeline placed in service ahead of schedule |url=https://www.businesswire.com/news/home/20190924006044/en/Gulf-Coast-Express-Pipeline-Service-Schedule |access-date=2019-12-31 |publisher=Business Wire}}</ref> and the others scheduled to come online during 2020–2022.<ref name="DOE-GFV-2019">{{Cite web |date=2019-06-01 |title=Natural Gas Flaring and Venting: State and Federal Regulatory Overview, Trends, and Impacts |url=https://www.energy.gov/sites/prod/files/2019/08/f65/Natural%20Gas%20Flaring%20and%20Venting%20Report.pdf |access-date=2019-12-29 |publisher=U.S. Department of Energy}}</ref>{{rp|23}}

====Installation bans====
To reduce its greenhouse emissions, the [[Netherlands]] is subsidizing a transition away from natural gas for all homes in the country by 2050. In [[Amsterdam]], no new residential gas accounts have been allowed since 2018, and all homes in the city are expected to be converted by 2040 to use the excess heat from adjacent industrial buildings and operations.<ref>{{Cite web |date=2018-10-01 |title=Van der Pekbuurt gaat als eerste Amsterdamse wijk van het aardgas af |url=https://www.at5.nl/artikelen/186860/maandag-1000-uur-van-der-pekbuurt-gaat-als-eerste-wijk-van-het-aardgas-af-2 |language=nl}}</ref>
Some cities in the United States have started prohibiting gas hookups for new houses, with state laws passed and under consideration to either require electrification or prohibit local requirements.<ref>{{Cite web |date=2021-03-09 |title=Dozens Of US Cities Are Banning Natural Gas Hookups In New Buildings — #CancelGas #ElectrifyEverything |url=https://cleantechnica.com/2021/03/09/dozens-of-us-cities-are-banning-natural-gas-hookups-in-new-buildings-cancelgas-electrifyeverything/}}</ref> New gas appliance hookups are banned in [[New York State]]<ref>{{cite news |url=https://www.washingtonpost.com/politics/2023/05/02/environment-gas-ban-stoves/239e436e-e92c-11ed-869e-986dd5713bc8_story.html |agency=[[Associated Press]] |title=Bye-bye blue flame? NY to require gas-free new buildings |author=Michael Hill |date=2 May 2023}}</ref> and the [[Australian Capital Territory]].<ref>{{Cite web |title=Canberra Natural Gas Bans To Hit Appliance Retailers |url=https://www.channelnews.com.au/canberra-natural-gas-bans-to-hit-appliance-retailers/ |access-date=2023-01-13 |language=en-US}}</ref> Additionally, the state of [[Victoria (state)|Victoria]] in Australia has implemented a ban on new natural gas hookups starting from January 1, 2024, as part of its gas substitution roadmap.<ref>{{Cite web |url=https://www.energy.vic.gov.au/renewable-energy/victorias-gas-substitution-roadmap |title=Victoria's Gas Substitution Roadmap |publisher=Victorian Government |access-date=2023-10-07}}</ref>  This followed campaigning which resulted in a prohibition on onshore gas exploration and production in Victoria in 2014. This was partially lifted in 2021 but a constitutional ban remains on fracking.<ref>{{Cite web |last=Rooney |first=Millie |date=2022-06-01 |title='Always look up': Connecting Community for a Win against Gas |url=https://commonslibrary.org/always-look-up-connecting-community-for-a-win-against-gas/ |access-date=2024-08-12 |website=The Commons Social Change Library |language=en-AU}}</ref>

The UK government is also experimenting with alternative home heating technologies to meet its climate goals.<ref>{{Cite web |title=Heat in Buildings |url=https://www.gov.uk/government/groups/heat-in-buildings |access-date=2021-08-09}}</ref> To preserve their businesses, natural gas utilities in the United States have been lobbying for laws preventing local electrification ordinances, and are promoting [[renewable natural gas]] and [[hydrogen fuel]].<ref>{{Cite news |last1=Jeff Brady |last2=Dan Charles |date=2021-02-22 |title=As Cities Grapple With Climate Change, Gas Utilities Fight To Stay In Business |publisher=[[NPR]] |url=https://www.npr.org/2021/02/22/967439914/as-cities-grapple-with-climate-change-gas-utilities-fight-to-stay-in-business}}</ref>

===Other pollutants===
Although natural gas produces far lower amounts of [[sulfur dioxide]] and [[NOx|nitrogen oxides]] (NOx) than other fossil fuels,<ref name=NGinASIA/> {{NOx}} from burning natural gas in homes can be a health hazard.<ref>{{Cite journal |last1=Lebel |first1=Eric D. |last2=Finnegan |first2=Colin J. |last3=Ouyang |first3=Zutao |last4=Jackson |first4=Robert B. |date=2022-02-15 |title=Methane and NO x Emissions from Natural Gas Stoves, Cooktops, and Ovens in Residential Homes |journal=Environmental Science & Technology |language=en |volume=56 |issue=4 |pages=2529–2539 |bibcode=2022EnST...56.2529L |doi=10.1021/acs.est.1c04707 |issn=0013-936X |pmid=35081712 |s2cid=246296077|doi-access=free }}</ref>

===Radionuclides===
Natural gas extraction also produces radioactive isotopes of [[polonium]] (Po-210), [[lead]] (Pb-210) and [[radon]] (Rn-220). Radon is a gas with initial activity from 5 to 200,000 [[becquerels]] per cubic meter of gas. It decays rapidly to Pb-210 which can build up as a thin film in gas extraction equipment.<ref>{{Cite web |date=29 April 2024 |title=Naturally Occurring Radioactive Materials (NORM) |url=http://www.world-nuclear.org/information-library/safety-and-security/radiation-and-health/naturally-occurring-radioactive-materials-norm.aspx |access-date=2017-11-22 |website=World Nuclear Association}}</ref>

==Safety concerns==
[[File:Gas pipeline odourant injection facility.JPG|thumb|A pipeline odorant injection station]]The natural gas extraction workforce face unique health and safety challenges.<ref>{{Cite web |date=2019-02-12 |title=CDC - NIOSH - NORA Oil and Gas Extraction Council |url=https://www.cdc.gov/nora/councils/oilgas/default.html |access-date=2019-03-14 |website=www.cdc.gov}}</ref><ref>{{Cite web |date=2019-02-12 |title=NORA Oil and Gas Extraction Council - Research Agenda |url=https://www.cdc.gov/nora/councils/oilgas/agenda.html |access-date=2019-03-14 |website=www.cdc.gov}}</ref>

===Production===
Some gas fields yield [[sour gas]] containing [[hydrogen sulfide]] ({{chem|H|2|S}}), a [[toxic]] compound when inhaled. [[Amine gas treating]], an industrial scale process which removes [[acidic]] [[gas]]eous components, is often used to remove hydrogen sulfide from natural gas.<ref name="Processing Natural Gas">{{Cite web |title=Processing Natural Gas |url=http://www.naturalgas.org/naturalgas/processing_ng.asp |url-status=dead |archive-url=https://web.archive.org/web/20110101053431/http://naturalgas.org/naturalgas/processing_ng.asp |archive-date=2011-01-01 |access-date=2011-02-06 |publisher=NaturalGas.org}}</ref>

Extraction of natural gas (or oil) leads to decrease in pressure in the [[oil reservoir|reservoir]]. Such decrease in pressure in turn may result in [[subsidence]] — sinking of the ground above. Subsidence may affect ecosystems, waterways, sewer and water supply systems, foundations, and so on.<ref>{{Cite book |last=Chiras |first=Daniel |url=https://books.google.com/books?id=ALKCupwW_RoC&q=subsidence |title=Environmental Science |publisher=Jones & Bartlett Learning |year=2012 |isbn=978-1-4496-1486-7 |page=283 |quote=However, natural gas extraction can cause subsidence in the vicinity of the well. One notable example is in the Los Angeles–Long Beach harbor area, where extensive oil and gas extraction began in 1928 and has caused the ground to drop {{convert|9|m|ft|abbr=off|sp=us}} in some areas. |via=Google Books}}</ref>

===Fracking===
{{Main|Environmental impact of hydraulic fracturing}}
Releasing natural gas from subsurface porous rock formations may be accomplished by a process called [[hydraulic fracturing]] or "fracking". Since the first commercial hydraulic fracturing operation in 1949, approximately one million wells have been hydraulically fractured in the United States.<ref>{{Cite news |last1=Brantley |first1=Susan L. |last2=Meyendorff |first2=Anna |date=2013-03-13 |title=The Facts on Fracking |work=The New York Times |url=https://www.nytimes.com/2013/03/14/opinion/global/the-facts-on-fracking.html}}</ref> The production of natural gas from hydraulically fractured wells has used the technological developments of directional and horizontal drilling, which improved access to natural gas in tight rock formations.<ref>Fitzgerald, Timothy. "Frackonomics: Some Economics of Hydraulic Fracturing." Case Western Reserve Law Review 63.4 (2013). Web. 1 Sept. 2015.</ref> Strong growth in the production of unconventional gas from hydraulically fractured wells occurred between 2000 and 2012.<ref>Chojna, J., Losoncz, M., & Suni, P. (November 2013). Shale Energy Shapes Global Energy Markets. National Institute Economic Review.</ref>

In hydraulic fracturing, well operators force water mixed with a variety of chemicals through the wellbore casing into the rock. The high pressure water breaks up or "fracks" the rock, which releases gas from the rock formation. Sand and other particles are added to the water as a [[proppant]] to keep the fractures in the rock open, thus enabling the gas to flow into the casing and then to the surface. Chemicals are added to the fluid to perform such functions as reducing friction and inhibiting corrosion. After the "frack", oil or gas is extracted and 30–70% of the frack fluid, i.e. the mixture of water, chemicals, sand, etc., flows back to the surface. Many gas-bearing formations also contain water, which will flow up the wellbore to the surface along with the gas, in both hydraulically fractured and non-hydraulically fractured wells. This [[produced water]] often has a high content of salt and other dissolved minerals that occur in the formation.<ref>{{Cite journal |last1=Yeboah |first1=N.N.N. |last2=Burns |first2=S.E. |year=2011 |title=Geological Disposal of Energy-Related Waste |journal=KSCE Journal of Civil Engineering |volume=15 |issue=4 |pages=701–702 |doi=10.1007/s12205-011-0010-x |bibcode=2011KSJCE..15..697Y |s2cid=109840417|doi-access=free }}</ref>

The volume of water used to hydraulically fracture wells varies according to the hydraulic fracturing technique. In the United States, the average volume of water used per hydraulic fracture has been reported as nearly 7,375 gallons for vertical oil and gas wells prior to 1953, nearly 197,000 gallons for vertical oil and gas wells between 2000 and 2010, and nearly 3&nbsp;million gallons for horizontal gas wells between 2000 and 2010.<ref>{{Cite report |url=http://pubs.usgs.gov/sir/2014/5131/pdf/sir2014-5131.pdf# |title=Trends in Hydraulic Fracturing Distributions and Treatment Fluids, Additives, Proppants, and Water Volumes Applied to Wells Drilled in the United States through 1947 through 2010—Data Analysis and Comparison to the Literature |last1=Gallegos |first1=Tanya J. |last2=Varela |first2=Brian A. |date=2015 |publisher=U.S. Geological Survey |issue=Web. 2 |volume=11 |docket=Scientific Investigations Report 2014.5131}}</ref>

Determining which fracking technique is appropriate for well productivity depends largely on the properties of the reservoir rock from which to extract oil or gas. If the rock is characterized by low-permeability – which refers to its ability to let substances, i.e. gas, pass through it, then the rock may be considered a source of [[tight gas]].<ref>{{Cite web |title=Our responsibility: Limit the impact of our industrial operations |url=http://www.total.com/en/energies-expertise/oil-gas/exploration-production/strategic-sectors/unconventional-gas/presentation/three-main-sources-unconventional-gas |website=Total.com |publisher=Total}}</ref> Fracking for shale gas, which is currently also known as a source of [[unconventional gas]], involves drilling a borehole vertically until it reaches a lateral shale rock formation, at which point the drill turns to follow the rock for hundreds or thousands of feet horizontally.<ref>{{Cite web |title=Shale Gas and Other Unconventional Sources of Natural Gas |url=http://www.ucsusa.org/clean_energy/our-energy-choices/coal-and-other-fossil-fuels/shale-gas-unconventional-sources-natural-gas.html |website=Union of Concerned Scientists}}</ref> In contrast, conventional oil and gas sources are characterized by higher rock permeability, which naturally enables the flow of oil or gas into the wellbore with less intensive hydraulic fracturing techniques than the production of tight gas has required.<ref>{{Cite web |title=How is Shale Gas Produced? |url=http://energy.gov/sites/prod/files/2013/04/f0/how_is_shale_gas_produced.pdf |website=Energy.gov}}</ref><ref>{{Cite web |title=U.S. Average Depth of Natural Gas Developmental Wells Drilled |url=http://www.eia.gov/dnav/pet/hist/LeafHandler.ashx?n=PET&s=E_ERTWG_XWDD_NUS_FW&f=A |website=U.S. Energy Information Administration (eia)}}</ref> The decades in development of drilling technology for conventional and [[unconventional oil]] and gas production have not only improved access to natural gas in low-permeability reservoir rocks, but also posed significant adverse impacts on environmental and public health.<ref>{{Cite web |date=2012-10-30 |title=The Environmental and Occupational Health Impacts of High-Volume Hydraulic Fracturing of Unconventional Gas Reserves |url=http://www.apha.org/policies-and-advocacy/public-health-policy-statements/policy-database/2014/10/02/15/37/hydraulic-fracturing |website=APHA}}</ref><ref>{{Cite web |date=2014-10-06 |title=Documents Reveal Billions of Gallons of Oil Industry Wastewater Illegally Injected into Central California Aquifers |url=http://www.biologicaldiversity.org/news/press_releases/2014/fracking-10-06-2014.html |publisher=Center for Biological Diversity}}</ref><ref>{{Cite journal |last1=Keranen |first1=K.M. |last2=Weingarten |first2=M. |last3=Abers |first3=G.A. |last4=Bekins |first4=B.A. |last5=Ge |first5=S. |date=2014-07-25 |title=Sharp increase in central Oklahoma seismicity since 2008 induced by massive wastewater injection |journal=Science |volume=345 |issue=6195 |pages=448–451 |bibcode=2014Sci...345..448K |doi=10.1126/science.1255802 |pmid=24993347 |s2cid=206558853|doi-access=free }}</ref><ref>{{Cite journal |last1=Osborn |first1=Stephen G. |last2=Vengosh |first2=Avner |last3=Warner |first3=Nathaniel R. |last4=Jackson |first4=Robert B. |date=2011-05-17 |title=Methane contamination of drinking water accompanying gas-well drilling and hydraulic fracturing |journal=Proceedings of the National Academy of Sciences |volume=108 |issue=20 |pages=8172–8176 |bibcode=2011PNAS..108.8172O |doi=10.1073/pnas.1100682108 |pmc=3100993 |pmid=21555547 |doi-access=free}}</ref>

The US EPA has acknowledged that toxic, carcinogenic chemicals, i.e. benzene and ethylbenzene, have been used as gelling agents in water and chemical mixtures for high volume horizontal fracturing (HVHF).<ref>{{Cite web |date=2012-10-18 |title=Quality Assurance Project Plan for the Chemical Characterization of Select Constituents Relevant to Hydraulic Fracturing |url=https://www.epa.gov/sites/production/files/documents/chemistry-qapp.pdf |access-date=2017-11-22 |publisher=U.S. Environmental Protection Agency}}</ref> Following the hydraulic fracture in HVHF, the water, chemicals, and frack fluid that return to the well's surface, called flowback or produced water, may contain radioactive materials, heavy metals, natural salts, and hydrocarbons which exist naturally in shale rock formations.<ref>{{Cite journal |last=Howarth |first=Robert W. |date=2011-09-15 |title=Should Fracking Stop? |journal=Nature |volume=477 |issue=7364 |pages=271–275 |doi=10.1038/477271a |pmid=21921896 |doi-access=free |s2cid=205067220}}</ref> Fracking chemicals, radioactive materials, heavy metals, and salts that are removed from the HVHF well by well operators are so difficult to remove from the water they are mixed with, and would so heavily [[water pollution|pollute]] the [[water cycle]], that most of the flowback is either recycled into other fracking operations or injected into deep underground wells, eliminating the water that HVHF required from the hydrologic cycle.<ref>{{Cite web |last=Josh Harkinson |date=2011-09-01 |title=As Texas Withers, Gas Industry Guzzles |url=https://www.motherjones.com/environment/2011/09/texas-drought-fracking-water |access-date=2017-11-22 |website=Mother Jones}}</ref>

Historically low gas prices have delayed the [[nuclear renaissance]], as well as the development of [[solar thermal energy]].<ref>{{Cite news |last=Mufson |first=Steven |date=2012-02-01 |title=Cheap natural gas jumbles energy markets, stirs fears it could inhibit renewables |language=en-US |newspaper=Washington Post |url=https://www.washingtonpost.com/business/economy/cheap-natural-gas-jumbles-energy-markets-stirs-fears-it-could-inhibit-renewables/2012/01/08/gIQApLr5hQ_story.html |access-date=2022-06-24 |issn=0190-8286}}</ref>

===Added odor===
In its native state, natural gas is colorless and almost [[odor]]less. In the US, the [[New London School explosion]] that occurred in 1937 in Texas caused a push for legislation requiring the addition of an odorant to assist consumers in detecting [[leak]]s. An [[odorizer]] with an unpleasant smell, such as [[thiophane]] or [[tert-Butylthiol]] (t-butyl mercaptan) may be added. Situations have occurred in which an odorant cannot be properly detected by an observer with a normal sense of smell despite being detectable by analytical instruments. This is caused by odor masking, when one odor overpowers the sensation of another. As of 2011, the industry is conducting research on the causes of odor masking.<ref>{{Cite journal |last1=Rawson |first1=Nancy |last2=Quraishi |first2=Ali |last3=Bruno |first3=Thomas J. |year=2011 |title=Findings and Recommendations From the Joint NIST—AGA Workshop on Odor Masking |journal=Journal of Research of the National Institute of Standards and Technology |volume=116 |issue=6 |pages=839–848 |doi=10.6028/jres.116.026 |pmc=4551224 |pmid=26989604}}</ref>{{Update inline|date=October 2022}}

===Risk of explosion===
[[File:Fire engines in Kiev, Ukraine.JPG|thumb|Gas network emergency vehicle responding to a major fire in [[Kyiv]], [[Ukraine]]]]

Explosions caused by natural [[gas leak]]s occur a few times each year. Individual homes, small businesses and other structures are most frequently affected when an internal leak builds up gas inside the structure. Leaks often result from excavation work, such as when contractors dig and strike pipelines, sometimes without knowing any damage resulted. Frequently, the blast is powerful enough to significantly damage a building but leave it standing. In these cases, the people inside tend to have minor to moderate injuries. Occasionally, the gas can collect in high enough quantities to cause a deadly explosion, destroying one or more buildings in the process. Many building codes now forbid the installation of gas pipes inside cavity walls or below floor boards to mitigate against this risk. Gas usually dissipates readily outdoors, but can sometimes collect in dangerous quantities if [[high pressure jet|flow rates are high enough]].<ref>{{Cite web |title=Data and Statistics Overview |url=https://www.phmsa.dot.gov/data-and-statistics/pipeline/data-and-statistics-overview |access-date=2021-07-22 |website=United States Department of Transport Pipeline and Hazardous Materials Safety Administration}}</ref> However, considering the tens of millions of structures that use the fuel, the individual risk from using natural gas is low.

===Risk of carbon monoxide inhalation===
Natural gas heating systems may cause [[carbon monoxide poisoning]] if unvented or poorly vented. Improvements in natural gas furnace designs have greatly reduced CO poisoning concerns. [[Carbon monoxide detector|Detectors]] are also available that warn of carbon monoxide or explosive gases such as methane and propane.<ref>US Consumer Product Safety Commission, [http://www.cpsc.gov/Global/Research-and-Statistics/Injury-Statistics/Carbon-Monoxide-Posioning/NonFireCarbonMonoxideDeathsAssociatedwiththeUseofConsumerProducts2011AnnualEstimatesSept2014.pdf Non-Fire Carbon Monoxide Deaths, 2011 Annual Estimate], September 2014.</ref>

==Energy content, statistics, and pricing==
{{Main|Natural gas prices}}
{{See also|Billion cubic metres of natural gas}}
{{Update section|date=October 2022}}
[[File:1980- Natural gas production, by country.svg |thumb|The U.S. and Russia have been the predominant producers of natural gas.<ref name=EIA_naturalGas_thru2022>{{cite web |title=International / DATA / Natural Gas / Download options / Export CSV (table) |url=https://www.eia.gov/international/data/world/natural-gas/dry-natural-gas-production?pd=3002&p=00g&u=0&f=A&v=mapbubble&a=-&i=none&vo=value&&t=C&g=00000000000000000000000000000000000000000000000001&l=249-ruvvvvvfvtvnvv1vrvvvvfvvvvvvfvvvou20evvvvvvvvvvnvvvs0008&s=315532800000&e=1640995200000 |publisher=U.S. Energy Information Administration |access-date=16 October 2024 |archive-url=https://archive.today/20241016165403/https://www.eia.gov/international/data/world/natural-gas/dry-natural-gas-production?pd=3002&p=00g&u=0&f=A&v=mapbubble&a=-&i=none&vo=value&vb=10&t=C&g=00000000000000000000000000000000000000000000000001&l=249-ruvvvvvfvtvnvv1vrvvvvfvvvvvvfvvvou20evvvvvvvvvvnvvvs0008&s=315532800000&e=1640995200000&ev=false |archive-date=16 October 2024 |url-status=live}}</ref>]]

Quantities of natural gas are measured in [[standard cubic meter]]s (cubic meter of gas at temperature {{convert|15|°C|°F|abbr=on}} and pressure {{convert|101.325|kPa|psi|abbr=on}}) or [[Standard cubic foot|standard cubic feet]] (cubic foot of gas at temperature 60.0&nbsp;°F and pressure {{convert|14.73|psi|kPa|abbr=on}}), 1 standard cubic meter&nbsp;=&nbsp;35.301&nbsp;standard cubic feet. The [[higher heating value|gross heat of combustion]] of commercial quality natural gas is around {{convert|39|MJ/m3|kWh/cuft|abbr=on}}, but this can vary by several percent. This is about 50 to 54&nbsp;MJ/kg depending on the density.<ref>{{Cite web |title=Gas Density, Molecular Weight and Density |url=http://www.teknopoli.com/PDF/Gas_Density_Table.pdf |website=teknopoli}}</ref><ref>Range calculated from {{Cite book |title=Chemical Engineers' Handbook |date=1973 |editor-last=Robert Perry and Cecil Chilton |pages=9–12}}</ref> For comparison, the [[heat of combustion]] of pure methane is 37.7&nbsp;MJ per standard cubic metre, or 55.5&nbsp;MJ/kg.

Except in the European Union, the U.S., and Canada, natural gas is sold in gigajoule retail units. LNG (liquefied natural gas) and LPG ([[liquefied petroleum gas]]) are traded in metric tonnes (1,000&nbsp;kg) or million BTU as spot deliveries. Long term natural gas distribution contracts are signed in cubic meters, and LNG contracts are in metric tonnes. The LNG and LPG is transported by specialized [[LNG carrier|transport ships]], as the gas is liquified at [[cryogenic]] temperatures. The specification of each LNG/LPG cargo will usually contain the energy content, but this information is in general not available to the public. The European Union aimed to cut its [[Russia in the European energy sector|gas dependency on Russia]] by two-thirds in 2022.<ref>{{Cite web |date=2022-02-08 |title=EU unveils plan to reduce Russia energy dependency |url=https://www.dw.com/en/eu-unveils-plan-to-reduce-russia-energy-dependency/a-61047997 |access-date=2022-03-08 |website=DW.COM |language=en-GB}}</ref>

In August 2015, possibly the largest natural gas discovery in history was made and notified by an Italian gas company ENI. The energy company indicated that it has unearthed a [[Giant oil and gas fields|"supergiant" gas field]] in the Mediterranean Sea covering about {{convert|40|sqmi}}. This was named the [[Zohr Field|Zohr]] gas field and could hold a potential {{convert|30|e12cuft|abbr=off|sp=us}} of natural gas. ENI said that the energy is about {{convert|5.5|e9BOE|abbr=~}}. The [[Zohr Field|Zohr]] field was found in the deep waters off the northern coast of Egypt and ENI claims that it will be the largest ever in the Mediterranean and even the world.<ref>{{Cite web |last=Goldman |first=David |date=2015-08-30 |title=Natural gas discovery could be largest ever |url=https://money.cnn.com/2015/08/30/news/companies/eni-gas-field/ |website=CNN Money}}</ref>

===European Union===
Gas prices for end users vary greatly across the [[European Union|EU]].<ref>{{Cite web |title=Energy Prices Report |url=http://www.energy.eu/#Domestic |access-date=2015-06-11 |website=Europe's Energy Portal}}</ref> A single European energy market, one of the key objectives of the EU, should level the prices of gas in all EU member states. Moreover, it would help to resolve supply and [[global warming]] issues,<ref>{{Cite web |title=Market analysis |url=http://ec.europa.eu/energy/observatory/gas/gas_en.htm |access-date=2015-06-11 |website=European Commission}}</ref> as well as strengthen relations with other Mediterranean countries and foster investments in the region.<ref>{{Cite journal |last=Farah |first=Paolo Davide |date=2015 |title=Offshore Natural Gas Resources in the Eastern Mediterranean in the Relations to the European Union: A Legal Perspective through the Lenses of MedReg |journal=Journal of World Energy Law and Business |volume=8 |issue=8 |ssrn=2695964}}</ref> During the [[prelude to the 2022 Russian invasion of Ukraine]], [[Qatar]] was asked by the US to supply emergency gas to the EU in case of supply disruptions.<ref>{{cite web|url=https://www.jpost.com/international/article-695077|title=Qatar seeks EU guarantee not to resell emergency gas|date=2022-02-01|access-date=2022-02-01|agency=Reuters}}</ref>

===United States===
In [[United States customary units|US units]], {{convert|1|cuft|L|adj=pre|standard |spell=in}} of natural gas produces around {{convert|1028|btu |kJ|lk=in}}. The actual heating value when the water formed does not condense is the [[lower heating value|net heat of combustion]] and can be as much as 10% less.<ref>[https://web.archive.org/web/20100531191519/http://www.energy.wsu.edu/documents/distributed/03_025_CHP_glossary_fct.pdf Heat value definitions]. WSU website. Retrieved 2008-05-19.</ref>

In the United States, retail sales are often in units of [[therm]]s (th); 1 therm = 100,000&nbsp;BTU. Gas sales to domestic consumers are often in units of 100 [[standard cubic feet]] (scf). [[Gas meter]]s measure the volume of gas used, and this is converted to therms by multiplying the volume by the energy content of the gas used during that period, which varies slightly over time. The typical annual consumption of a single family residence is 1,000 therms or one [[Residential Customer Equivalent]] (RCE). Wholesale transactions are generally done in [[decatherm]]s (Dth), thousand decatherms (MDth), or million decatherms (MMDth). A million decatherms is a trillion BTU, roughly a billion cubic feet of natural gas.

The price of natural gas varies greatly depending on location and type of consumer. The typical caloric value of natural gas is roughly 1,000&nbsp;BTU per cubic foot, depending on gas composition. Natural gas in the United States is traded as a [[futures contract]] on the [[New York Mercantile Exchange]]. Each contract is for 10,000&nbsp;million BTU or {{convert|10|e9BTU|GJ|0|abbr=unit}}. Thus, if the price of gas is $10/million BTU on the NYMEX, the contract is worth $100,000.

===Canada===
{{Unreferenced section|date=October 2022}}
Canada uses [[metric units|metric]] measure for internal trade of [[Petrochemical|petrochemical products]]. Consequently, natural gas is sold by the gigajoule (GJ), cubic meter (m<sup>3</sup>) or thousand cubic meters (E3m3). Distribution infrastructure and meters almost always meter volume (cubic foot or cubic meter). Some jurisdictions, such as Saskatchewan, sell gas by volume only. Other jurisdictions, such as Alberta, sell gas by energy content (GJ). In these areas, almost all meters for residential and small commercial customers measure volume (m<sup>3</sup> or ft<sup>3</sup>), and billing statements include a multiplier to convert the volume to the energy content of the local gas supply.

A [[gigajoule]] (GJ) is a measure approximately equal to {{convert|0.5|oilbbl|L|order=flip|sigfig=1|abbr=off}} of oil, or {{convert|1000|ft3|m3|disp=or|abbr=on|order=flip}} or 1&nbsp;million BTUs of gas. The energy content of gas supply in Canada can vary from {{convert|37|to|43|MJ/m3|abbr=on}} depending on gas supply and processing between the wellhead and the customer.

==Adsorbed natural gas (ANG)==
Natural gas may be stored by adsorbing it to the porous solids called sorbents. The optimal condition for methane storage is at room temperature and atmospheric pressure. Pressures up to 4 MPa (about 40 times atmospheric pressure) will yield greater storage capacity. The most common sorbent used for ANG is activated carbon (AC), primarily in three forms: Activated Carbon Fiber (ACF), Powdered Activated Carbon (PAC), and activated carbon monolith.<ref>{{Cite web |title=Adsorbed Natural Gas |url=http://scopewe.com/category/chemical-engineering/ang |url-status=usurped |archive-url=https://web.archive.org/web/20131109181802/http://scopewe.com/category/chemical-engineering/ang/ |archive-date=2013-11-09 |access-date=2015-06-11 |website=scopeWe – a Virtual Engineer}}</ref>

==See also==
{{Portal|Energy|Renewable energy}}
* [[Associated petroleum gas]]
* [[Energy transition]]
* [[Gas/oil ratio]]
* [[Liquefied natural gas]]
* [[Natural gas by country]]
* [[Peak gas]]
* [[Power-to-gas]]
* [[Renewable natural gas]]
* [[Strategic natural gas reserve]]
* [[World energy supply and consumption]]

==References==
{{Reflist}}

==Further reading==
* {{cite book |last1=Blanchard |first1=Charles |title=The Extraction State: A History of Natural Gas in America |date=2021 |publisher=[[University of Pittsburgh Press]] |location=Pittsburgh |isbn=9780822966760}}

==External links==
* [https://ggon.org/fossil-tracker/ Global Fossil Infrastructure Tracker]
* [https://gogel.org/ Global Oil & Gas Exit List (GOGEL)] by Urgewald
* [https://carbonmapper.org/data/ Carbon Mapper Data Portal featuring methane point source data]

{{Fuel gas}}

{{Authority control}}

{{DEFAULTSORT:Natural Gas}}
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[[Category:Fuel gas]]
[[Category:Natural gas| ]]