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Numbers are in billion cubic meters per year.<a href="#cite_note-1">[1]</a></div> </div> </div> <div class="thumb tright"> <div class="thumbinner" style="width:372px;"><a href="/web/20160627225612/https://en.wikipedia.org/wiki/File:World_-_Natural_Gas_Production_of_Countries.png" class="image"><img alt="" src="//web.archive.org/web/20160627225612im_/https://upload.wikimedia.org/wikipedia/commons/thumb/2/23/World_-_Natural_Gas_Production_of_Countries.png/370px-World_-_Natural_Gas_Production_of_Countries.png" width="370" height="162" class="thumbimage" srcset="//web.archive.org/web/20160627225612im_/https://upload.wikimedia.org/wikipedia/commons/thumb/2/23/World_-_Natural_Gas_Production_of_Countries.png/555px-World_-_Natural_Gas_Production_of_Countries.png 1.5x, //web.archive.org/web/20160627225612im_/https://upload.wikimedia.org/wikipedia/commons/thumb/2/23/World_-_Natural_Gas_Production_of_Countries.png/740px-World_-_Natural_Gas_Production_of_Countries.png 2x" data-file-width="1425" data-file-height="625"/></a> <div class="thumbcaption"> <div class="magnify"><a href="/web/20160627225612/https://en.wikipedia.org/wiki/File:World_-_Natural_Gas_Production_of_Countries.png" class="internal" title="Enlarge"></a></div> <a href="/web/20160627225612/https://en.wikipedia.org/wiki/List_of_countries_by_natural_gas_production" title="List of countries by natural gas production">Natural gas extraction by countries</a> in cubic meters per year</div> </div> </div> Natural gas is a naturally occurring <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Hydrocarbon" title="Hydrocarbon">hydrocarbon</a> <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Gas" title="Gas">gas</a> mixture consisting primarily of <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Methane" title="Methane">methane</a>, but commonly including varying amounts of other higher <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Alkanes" class="mw-redirect" title="Alkanes">alkanes</a>, and sometimes a small percentage of <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Carbon_dioxide" title="Carbon dioxide">carbon dioxide</a>, <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Nitrogen" title="Nitrogen">nitrogen</a>, <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Hydrogen_sulfide" title="Hydrogen sulfide">hydrogen sulfide</a>, or <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Helium" title="Helium">helium</a>.<a href="#cite_note-2">[2]</a> It is formed when layers of decomposing plant and animal matter are exposed to intense heat and pressure supplied by existing under the surface of the Earth over millions of years. The energy that the plants originally obtained from the sun is stored in the form of chemical bonds in the gas.<a href="#cite_note-epa_ng-3">[3]</a> Natural gas is a <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Fossil_fuel" title="Fossil fuel">fossil fuel</a> used as a source of energy for heating, cooking, and electricity generation. It is also used as fuel for vehicles and as a chemical feedstock in the manufacture of <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Plastics" class="mw-redirect" title="Plastics">plastics</a> and other commercially important <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Organic_compound" title="Organic compound">organic chemicals</a>. It is a <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Non-renewable_resource" title="Non-renewable resource">non-renewable resource</a>.<a href="#cite_note-epa_ng-3">[3]</a> Natural gas is found in deep underground rock formations or associated with other hydrocarbon reservoirs in <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Coal_bed" class="mw-redirect" title="Coal bed">coal beds</a> and as <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Methane_clathrate" title="Methane clathrate">methane clathrates</a>. <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Petroleum" title="Petroleum">Petroleum</a> is another resource and fossil fuel found in close proximity to, and with natural gas. Most natural gas was created over time by two mechanisms: biogenic and thermogenic. Biogenic gas is created by <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Methanogen" title="Methanogen">methanogenic</a> organisms in <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Marsh" title="Marsh">marshes</a>, <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Bog" title="Bog">bogs</a>, <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Landfill" title="Landfill">landfills</a>, and shallow sediments. Deeper in the earth, at greater temperature and pressure, thermogenic gas is created from buried organic material.<a href="#cite_note-4">[4]</a><a href="#cite_note-5">[5]</a> When gas is associated with petroleum production it may be considered a byproduct and be burnt as <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Gas_flare" title="Gas flare">flare gas</a>. The <a href="/web/20160627225612/https://en.wikipedia.org/wiki/World_Bank" title="World Bank">World Bank</a> estimates that over 150 billion cubic meters of natural gas are flared or vented annually.<a href="#cite_note-6">[6]</a> Before natural gas can be used as a fuel, it must be <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Natural_gas_processing" class="mw-redirect" title="Natural gas processing">processed</a> to remove impurities, including water, to meet the specifications of marketable natural gas. The by-products of this processing include: <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Ethane" title="Ethane">ethane</a>, <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Propane" title="Propane">propane</a>, <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Butane" title="Butane">butanes</a>, <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Pentane" title="Pentane">pentanes</a>, and higher molecular weight hydrocarbons, hydrogen sulfide (which may be converted into pure <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Sulfur" title="Sulfur">sulfur</a>), <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Carbon_dioxide" title="Carbon dioxide">carbon dioxide</a>, <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Water_vapor" title="Water vapor">water vapor</a>, and sometimes <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Helium" title="Helium">helium</a> and <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Nitrogen" title="Nitrogen">nitrogen</a>. Natural gas is often informally referred to simply as "gas", especially when compared to other energy sources such as oil or coal. However, it is not to be confused with <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Gasoline" title="Gasoline">gasoline</a>, especially in North America, where the term gasoline is often shortened in colloquial usage to gas. Natural gas was used by the Chinese in about 500 BC (possibly even 1000 BC<a href="#cite_note-7">[7]</a>). They discovered a way to transport gas seeping from the ground in crude pipelines of bamboo to where it was used to boil salt water to <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Salt_in_Chinese_history" title="Salt in Chinese history">extract the salt</a>,<a href="#cite_note-8">[8]</a> in the <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Ziliujing_District" title="Ziliujing District">Ziliujing District</a> of <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Sichuan" title="Sichuan">Sichuan</a>. The world's first industrial extraction of natural gas started at <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Fredonia,_New_York" title="Fredonia, New York">Fredonia, New York</a>, USA in 1825.<a href="#cite_note-9">[9]</a> By 2009, 66 trillion cubic meters (or 8%) had been used out of the total 850 trillion cubic meters of estimated remaining recoverable reserves of natural gas.<a href="#cite_note-worldenergyoutlook.org-10">[10]</a> Based on an estimated 2015 world consumption rate of about 3.4 trillion cubic meters of gas per year, the total estimated remaining economically recoverable reserves of natural gas would last 250 years at current consumption rates. An annual increase in usage of 2–3% could result in currently recoverable reserves lasting significantly less, perhaps as few as 80 to 100 years.<a href="#cite_note-worldenergyoutlook.org-10">[10]</a> <div class="thumb tright"> <div class="thumbinner" style="width:252px;"><a href="/web/20160627225612/https://en.wikipedia.org/wiki/File:Chuhuo.jpg" class="image"><img alt="" src="//web.archive.org/web/20160627225612im_/https://upload.wikimedia.org/wikipedia/commons/thumb/0/0c/Chuhuo.jpg/250px-Chuhuo.jpg" width="250" height="188" class="thumbimage" srcset="//web.archive.org/web/20160627225612im_/https://upload.wikimedia.org/wikipedia/commons/thumb/0/0c/Chuhuo.jpg/375px-Chuhuo.jpg 1.5x, //web.archive.org/web/20160627225612im_/https://upload.wikimedia.org/wikipedia/commons/thumb/0/0c/Chuhuo.jpg/500px-Chuhuo.jpg 2x" data-file-width="800" data-file-height="600"/></a> <div class="thumbcaption"> <div class="magnify"><a href="/web/20160627225612/https://en.wikipedia.org/wiki/File:Chuhuo.jpg" class="internal" title="Enlarge"></a></div> Natural gas coming out of the ground in Taiwan.</div> </div> </div> <div id="toc" class="toc"> <div id="toctitle"> <h2>Contents</h2> </div> <ul> <li class="toclevel-1 tocsection-1"><a href="#Sources">1 Sources</a> <ul> <li class="toclevel-2 tocsection-2"><a href="#Natural_gas">1.1 Natural gas</a></li> <li class="toclevel-2 tocsection-3"><a href="#Shale_gas">1.2 Shale gas</a></li> <li class="toclevel-2 tocsection-4"><a href="#Town_gas">1.3 Town gas</a></li> <li class="toclevel-2 tocsection-5"><a href="#Biogas">1.4 Biogas</a></li> <li class="toclevel-2 tocsection-6"><a href="#Crystallized_natural_gas.C2.A0.E2.80.94_hydrates">1.5 Crystallized natural gas — hydrates</a></li> </ul> </li> <li class="toclevel-1 tocsection-7"><a href="#Natural_gas_processing">2 Natural gas processing</a></li> <li class="toclevel-1 tocsection-8"><a href="#Depletion">3 Depletion</a></li> <li class="toclevel-1 tocsection-9"><a href="#Uses">4 Uses</a> <ul> <li class="toclevel-2 tocsection-10"><a href="#Mid-stream_natural_gas">4.1 Mid-stream natural gas</a></li> <li class="toclevel-2 tocsection-11"><a href="#Power_generation">4.2 Power generation</a></li> <li class="toclevel-2 tocsection-12"><a href="#Domestic_use">4.3 Domestic use</a></li> <li class="toclevel-2 tocsection-13"><a href="#Transportation">4.4 Transportation</a></li> <li class="toclevel-2 tocsection-14"><a href="#Fertilizers">4.5 Fertilizers</a></li> <li class="toclevel-2 tocsection-15"><a href="#Hydrogen">4.6 Hydrogen</a></li> <li class="toclevel-2 tocsection-16"><a href="#Other">4.7 Other</a></li> </ul> </li> <li class="toclevel-1 tocsection-17"><a href="#Storage_and_transport">5 Storage and transport</a></li> <li class="toclevel-1 tocsection-18"><a href="#Environmental_effects">6 Environmental effects</a> <ul> <li class="toclevel-2 tocsection-19"><a href="#Effect_of_natural_gas_release">6.1 Effect of natural gas release</a></li> <li class="toclevel-2 tocsection-20"><a href="#CO2_emissions">6.2 CO2 emissions</a></li> <li class="toclevel-2 tocsection-21"><a href="#Other_pollutants">6.3 Other pollutants</a></li> </ul> </li> <li class="toclevel-1 tocsection-22"><a href="#Safety_concerns">7 Safety concerns</a> <ul> <li class="toclevel-2 tocsection-23"><a href="#Production">7.1 Production</a></li> <li class="toclevel-2 tocsection-24"><a href="#Fracking">7.2 Fracking</a></li> <li class="toclevel-2 tocsection-25"><a href="#Odor_is_Added">7.3 Odor is Added</a></li> <li class="toclevel-2 tocsection-26"><a href="#Risk_of_Explosion">7.4 Risk of Explosion</a></li> <li class="toclevel-2 tocsection-27"><a href="#Risk_of_Carbon_Monoxide_Inhalation">7.5 Risk of Carbon Monoxide Inhalation</a></li> </ul> </li> <li class="toclevel-1 tocsection-28"><a href="#Energy_content.2C_statistics.2C_and_pricing">8 Energy content, statistics, and pricing</a> <ul> <li class="toclevel-2 tocsection-29"><a href="#European_Union">8.1 European Union</a></li> <li class="toclevel-2 tocsection-30"><a href="#United_States">8.2 United States</a></li> <li class="toclevel-2 tocsection-31"><a href="#Canada">8.3 Canada</a></li> <li class="toclevel-2 tocsection-32"><a href="#Elsewhere">8.4 Elsewhere</a></li> </ul> </li> <li class="toclevel-1 tocsection-33"><a href="#Natural_gas_as_an_asset_class_for_institutional_investors">9 Natural gas as an asset class for institutional investors</a></li> <li class="toclevel-1 tocsection-34"><a href="#Adsorbed_natural_gas_.28ANG.29">10 Adsorbed natural gas (ANG)</a></li> <li class="toclevel-1 tocsection-35"><a href="#See_also">11 See also</a></li> <li class="toclevel-1 tocsection-36"><a href="#References">12 References</a></li> <li class="toclevel-1 tocsection-37"><a href="#External_links">13 External links</a></li> </ul> </div> <h2>Sources[<a href="/web/20160627225612/https://en.wikipedia.org/w/index.php?title=Natural_gas&action=edit&section=1" title="Edit section: Sources">edit</a>]</h2> <div role="note" class="hatnote">See also: <a href="/web/20160627225612/https://en.wikipedia.org/wiki/List_of_natural_gas_fields" title="List of natural gas fields">List of natural gas fields</a>, <a href="/web/20160627225612/https://en.wikipedia.org/wiki/List_of_countries_by_natural_gas_proven_reserves" title="List of countries by natural gas proven reserves">List of countries by natural gas proven reserves</a>, and <a href="/web/20160627225612/https://en.wikipedia.org/wiki/List_of_countries_by_natural_gas_production" title="List of countries by natural gas production">List of countries by natural gas production</a></div> <h3>Natural gas[<a href="/web/20160627225612/https://en.wikipedia.org/w/index.php?title=Natural_gas&action=edit&section=2" title="Edit section: Natural gas">edit</a>]</h3> <div class="thumb tright"> <div class="thumbinner" style="width:172px;"><a href="/web/20160627225612/https://en.wikipedia.org/wiki/File:BarnettShaleDrilling-9323.jpg" class="image"><img alt="" src="//web.archive.org/web/20160627225612im_/https://upload.wikimedia.org/wikipedia/commons/thumb/5/5d/BarnettShaleDrilling-9323.jpg/170px-BarnettShaleDrilling-9323.jpg" width="170" height="256" class="thumbimage" srcset="//web.archive.org/web/20160627225612im_/https://upload.wikimedia.org/wikipedia/commons/thumb/5/5d/BarnettShaleDrilling-9323.jpg/255px-BarnettShaleDrilling-9323.jpg 1.5x, //web.archive.org/web/20160627225612im_/https://upload.wikimedia.org/wikipedia/commons/thumb/5/5d/BarnettShaleDrilling-9323.jpg/340px-BarnettShaleDrilling-9323.jpg 2x" data-file-width="1872" data-file-height="2816"/></a> <div class="thumbcaption"> <div class="magnify"><a href="/web/20160627225612/https://en.wikipedia.org/wiki/File:BarnettShaleDrilling-9323.jpg" class="internal" title="Enlarge"></a></div> Natural gas <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Drilling_rig" title="Drilling rig">drilling rig</a> in Texas.</div> </div> </div> <div class="thumb tright"> <div class="thumbinner" style="width:222px;"><a href="/web/20160627225612/https://en.wikipedia.org/wiki/File:Gas_Production_Top_5_Countries.png" class="image"><img alt="" src="//web.archive.org/web/20160627225612im_/https://upload.wikimedia.org/wikipedia/commons/thumb/d/de/Gas_Production_Top_5_Countries.png/220px-Gas_Production_Top_5_Countries.png" width="220" height="147" class="thumbimage" srcset="//web.archive.org/web/20160627225612im_/https://upload.wikimedia.org/wikipedia/commons/thumb/d/de/Gas_Production_Top_5_Countries.png/330px-Gas_Production_Top_5_Countries.png 1.5x, //web.archive.org/web/20160627225612im_/https://upload.wikimedia.org/wikipedia/commons/thumb/d/de/Gas_Production_Top_5_Countries.png/440px-Gas_Production_Top_5_Countries.png 2x" data-file-width="2025" data-file-height="1350"/></a> <div class="thumbcaption"> <div class="magnify"><a href="/web/20160627225612/https://en.wikipedia.org/wiki/File:Gas_Production_Top_5_Countries.png" class="internal" title="Enlarge"></a></div> Trends in the top five natural gas-producing countries (US EIA data)</div> </div> </div> In the 19th century, natural gas was usually obtained as a by-product of <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Oil_well" title="Oil well">producing oil</a>, since the small, light gas carbon chains came out of solution as the extracted fluids underwent pressure reduction from the <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Petroleum_reservoir" title="Petroleum reservoir">reservoir</a> to the surface, similar to uncapping a soft drink bottle where the carbon dioxide <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Effervesce" class="mw-redirect" title="Effervesce">effervesces</a>. Unwanted natural gas was a disposal problem in the active oil fields. If there was not a market for natural gas near the <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Wellhead" title="Wellhead">wellhead</a> it was prohibitively expensive to pipe to the end user. In the 19th century and early 20th century, unwanted gas was usually burned off at oil fields. Today, unwanted gas (or <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Stranded_gas_reserve" title="Stranded gas reserve">stranded gas</a> without a market) associated with oil extraction often is returned to the reservoir with 'injection' wells while awaiting a possible future market or to repressurize the formation, which can enhance extraction rates from other wells. In regions with a high natural gas demand (such as the US), pipelines are constructed when it is economically feasible to transport gas from a wellsite to an <a href="/web/20160627225612/https://en.wikipedia.org/wiki/End_consumer" class="mw-redirect" title="End consumer">end consumer</a>. In addition to transporting gas via pipelines for use in power generation, other end uses for natural gas include export as <a href="/web/20160627225612/https://en.wikipedia.org/wiki/LNG" class="mw-redirect" title="LNG">liquefied natural gas</a> (LNG) or conversion of natural gas into other liquid products via <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Gas-to-liquids" class="mw-redirect" title="Gas-to-liquids">gas-to-liquids</a> (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 <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Fischer%E2%80%93Tropsch" class="mw-redirect" title="Fischer–Tropsch">Fischer–Tropsch</a> (F–T), methanol to gasoline (MTG) and <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Syngas_to_gasoline_plus" title="Syngas to gasoline plus">STG+</a>. 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.<a href="#cite_note-STG.2B_White_Paper-11">[11]</a> In 2011, <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Royal_Dutch_Shell" title="Royal Dutch Shell">Royal Dutch Shell’s</a> 140,000 barrel per day F–T plant went into operation in <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Qatar" title="Qatar">Qatar</a>. Natural gas can be "associated" (found in <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Oil_field" title="Oil field">oil fields</a>), or "non-associated" (isolated in <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Natural_gas_field" title="Natural gas field">natural gas fields</a>), and is also found in <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Coal_bed" class="mw-redirect" title="Coal bed">coal beds</a> (as <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Coalbed_methane" title="Coalbed methane">coalbed methane</a>).<a href="#cite_note-12">[12]</a> It sometimes contains a significant amount of <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Ethane" title="Ethane">ethane</a>, <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Propane" title="Propane">propane</a>, <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Butane" title="Butane">butane</a>, and <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Pentane" title="Pentane">pentane</a>—heavier hydrocarbons removed for commercial use prior to the <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Methane" title="Methane">methane</a> being sold as a consumer fuel or chemical plant feedstock. Non-hydrocarbons such as <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Carbon_dioxide" title="Carbon dioxide">carbon dioxide</a>, <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Nitrogen" title="Nitrogen">nitrogen</a>, <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Helium" title="Helium">helium</a> (rarely), and <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Hydrogen_sulfide" title="Hydrogen sulfide">hydrogen sulfide</a> must also be removed before the natural gas can be transported.<a href="#cite_note-13">[13]</a> 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 <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Natural_gas_industry" class="mw-redirect" title="Natural gas industry">natural gas industry</a> is extracting an increasing quantity of gas from challenging <a href="/web/20160627225612/https://en.wikipedia.org/wiki/History_of_the_petroleum_industry_in_Canada_(natural_gas)#Unconventional_gas" title="History of the petroleum industry in Canada (natural gas)">resource types</a>: <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Sour_gas" title="Sour gas">sour gas</a>, <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Tight_gas" title="Tight gas">tight gas</a>, <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Shale_gas" title="Shale gas">shale gas</a>, and <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Coalbed_methane" title="Coalbed methane">coalbed methane</a>. 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 CIA (47.6 trillion cubic meters),<a href="#cite_note-14">[14]</a> the US Energy Information Administration (47.8 tcm),<a href="#cite_note-15">[15]</a> and OPEC (48.7 tcm).<a href="#cite_note-16">[16]</a> However, BP credits Russia with only 32.9 tcm,<a href="#cite_note-17">[17]</a> which would place it in second place, slightly behind Iran (33.1 to 33.8 tcm, depending on the source). With <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Gazprom" title="Gazprom">Gazprom</a>, Russia is frequently the world's largest natural gas extractor. Major proven resources (in billion cubic meters) are world 187,300 (2013), Iran 33,600 (2013), Russia 32,900 (2013), Qatar 25,100 (2013), Turkmenistan 17,500 (2013) and the United States 8,500 (2013). It is estimated that there are about 900 trillion cubic meters of "unconventional" gas such as <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Shale_gas" title="Shale gas">shale gas</a>, of which 180 trillion may be recoverable.<a href="#cite_note-18">[18]</a> In turn, many studies from <a href="/web/20160627225612/https://en.wikipedia.org/wiki/MIT" class="mw-redirect" title="MIT">MIT</a>, <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Black_%26_Veatch" title="Black & Veatch">Black & Veatch</a> and the <a href="/web/20160627225612/https://en.wikipedia.org/wiki/United_States_Department_of_Energy" title="United States Department of Energy">DOE</a> predict that natural gas will account for a larger portion of electricity generation and heat in the future.<a href="#cite_note-19">[19]</a> The world's largest gas field is the offshore <a href="/web/20160627225612/https://en.wikipedia.org/wiki/South_Pars_/_North_Dome_Gas-Condensate_field" title="South Pars / North Dome Gas-Condensate field">South Pars / North Dome Gas-Condensate field</a>, shared between Iran and Qatar. It is estimated to have 51 trillion cubic meters of natural gas and 50 billion barrels of 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 <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Supercritical_fluid" title="Supercritical fluid">supercritical</a> (pressure/temperature) conditions, the higher molecular weight components may partially condense upon isothermic depressurizing—an effect called <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Retrograde_condensation" title="Retrograde condensation">retrograde condensation</a>. 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 <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Natural_gas_processing" class="mw-redirect" title="Natural gas processing">gas plant</a> is to collect this condensate. The resulting liquid is called natural gas liquid (NGL) and has commercial value. <h3>Shale gas[<a href="/web/20160627225612/https://en.wikipedia.org/w/index.php?title=Natural_gas&action=edit&section=3" title="Edit section: Shale gas">edit</a>]</h3> <table class="metadata plainlinks ambox ambox-content ambox-globalize" role="presentation"> <tr> <td class="mbox-image"> <div style="width:52px"><img alt="Globe icon." src="//web.archive.org/web/20160627225612im_/https://upload.wikimedia.org/wikipedia/commons/thumb/b/bd/Ambox_globe_content.svg/48px-Ambox_globe_content.svg.png" width="48" height="40" srcset="//web.archive.org/web/20160627225612im_/https://upload.wikimedia.org/wikipedia/commons/thumb/b/bd/Ambox_globe_content.svg/73px-Ambox_globe_content.svg.png 1.5x, //web.archive.org/web/20160627225612im_/https://upload.wikimedia.org/wikipedia/commons/thumb/b/bd/Ambox_globe_content.svg/97px-Ambox_globe_content.svg.png 2x" data-file-width="350" data-file-height="290"/></div> </td> <td class="mbox-text">The examples and perspective in this article deal primarily with the United States and do not represent a <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Wikipedia:WikiProject_Countering_systemic_bias" title="Wikipedia:WikiProject Countering systemic bias">worldwide view</a> of the subject. Please <a class="external text" href="//web.archive.org/web/20160627225612/https://en.wikipedia.org/w/index.php?title=Natural_gas&action=edit">improve this article</a> and discuss the issue on the <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Talk:Natural_gas" title="Talk:Natural gas">talk page</a>. (September 2013) (<a href="/web/20160627225612/https://en.wikipedia.org/wiki/Help:Maintenance_template_removal" title="Help:Maintenance template removal">Learn how and when to remove this template message</a>)</td> </tr> </table> <div class="thumb tright"> <div class="thumbinner" style="width:452px;"><a href="/web/20160627225612/https://en.wikipedia.org/wiki/File:GasDepositDiagram.jpg" class="image"><img alt="" src="//web.archive.org/web/20160627225612im_/https://upload.wikimedia.org/wikipedia/commons/thumb/b/bb/GasDepositDiagram.jpg/450px-GasDepositDiagram.jpg" width="450" height="296" class="thumbimage" srcset="//web.archive.org/web/20160627225612im_/https://upload.wikimedia.org/wikipedia/commons/thumb/b/bb/GasDepositDiagram.jpg/675px-GasDepositDiagram.jpg 1.5x, //web.archive.org/web/20160627225612im_/https://upload.wikimedia.org/wikipedia/commons/b/bb/GasDepositDiagram.jpg 2x" data-file-width="718" data-file-height="473"/></a> <div class="thumbcaption"> <div class="magnify"><a href="/web/20160627225612/https://en.wikipedia.org/wiki/File:GasDepositDiagram.jpg" class="internal" title="Enlarge"></a></div> The location of <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Shale_gas" title="Shale gas">shale gas</a> compared to other types of gas deposits.</div> </div> </div> <div role="note" class="hatnote relarticle mainarticle">Main article: <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Shale_gas" title="Shale gas">Shale gas</a></div> <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Shale_gas" title="Shale gas">Shale gas</a> is natural gas produced from <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Shale" title="Shale">shale</a>. Because shale has matrix permeability 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 <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Hydraulic_fracturing" title="Hydraulic fracturing">hydraulic fracturing</a>. Since 2000, shale gas has become a major source of natural gas in the United States and Canada.<a href="#cite_note-20">[20]</a> Following the success in the United States, shale gas exploration is beginning in countries such as Poland, China, and South Africa.<a href="#cite_note-21">[21]</a><a href="#cite_note-22">[22]</a><a href="#cite_note-23">[23]</a> Because of this increase in shale production, the United States is now the number one natural gas producer in the world<a href="#cite_note-24">[24]</a> <h3>Town gas[<a href="/web/20160627225612/https://en.wikipedia.org/w/index.php?title=Natural_gas&action=edit&section=4" title="Edit section: Town gas">edit</a>]</h3> <div role="note" class="hatnote relarticle mainarticle">Main article: <a href="/web/20160627225612/https://en.wikipedia.org/wiki/History_of_manufactured_gas" title="History of manufactured gas">History of manufactured gas</a></div> <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Town_gas" class="mw-redirect" title="Town gas">Town gas</a> is a flammable gaseous fuel made by the destructive distillation of <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Coal" title="Coal">coal</a>. It contains a variety of calorific gases including <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Hydrogen" title="Hydrogen">hydrogen</a>, <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Carbon_monoxide" title="Carbon monoxide">carbon monoxide</a>, <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Methane" title="Methane">methane</a>, and other volatile <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Hydrocarbons" class="mw-redirect" title="Hydrocarbons">hydrocarbons</a>, together with small quantities of non-calorific gases such as <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Carbon_dioxide" title="Carbon dioxide">carbon dioxide</a> and <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Nitrogen" title="Nitrogen">nitrogen</a>, and is 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. Still, it remains the best option in some specific cases and it may be so into the future. Most town "gashouses" located in the eastern US in the late 19th and early 20th centuries were simple by-product <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Coke_(fuel)" title="Coke (fuel)">coke</a> 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 <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Coal_tar" title="Coal tar">coal tar</a> (or <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Asphalt" title="Asphalt">asphalt</a>) 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. <h3>Biogas[<a href="/web/20160627225612/https://en.wikipedia.org/w/index.php?title=Natural_gas&action=edit&section=5" title="Edit section: Biogas">edit</a>]</h3> <div role="note" class="hatnote relarticle mainarticle">Main article: <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Biogas" title="Biogas">Biogas</a></div> <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Methanogen" title="Methanogen">Methanogenic archaea</a> are responsible for all biological sources of methane. Some live in symbiotic relationships with other life forms, including <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Termite" title="Termite">termites</a>, <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Ruminant" title="Ruminant">ruminants</a>, and cultivated crops. Other sources of <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Methane" title="Methane">methane</a>, the principal component of natural gas, include <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Landfill_gas" title="Landfill gas">landfill gas</a>, biogas, and <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Methane_hydrate" class="mw-redirect" title="Methane hydrate">methane hydrate</a>. When methane-rich gases are produced by the <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Anaerobic_decay" class="mw-redirect" title="Anaerobic decay">anaerobic decay</a> of non-fossil <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Organic_compound" title="Organic compound">organic</a> matter (<a href="/web/20160627225612/https://en.wikipedia.org/wiki/Biomass" title="Biomass">biomass</a>), these are referred to as biogas (or natural biogas). Sources of biogas include <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Swamp" title="Swamp">swamps</a>, <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Marsh" title="Marsh">marshes</a>, and <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Landfill" title="Landfill">landfills</a> (see <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Landfill_gas" title="Landfill gas">landfill gas</a>), as well as <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Agricultural_waste" class="mw-redirect" title="Agricultural waste">agricultural waste</a> materials such as <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Sewage" title="Sewage">sewage</a> <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Sludge" title="Sludge">sludge</a> and <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Manure" title="Manure">manure</a><a href="#cite_note-25">[25]</a> by way of <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Anaerobic_digester" class="mw-redirect" title="Anaerobic digester">anaerobic digesters</a>, in addition to <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Enteric_fermentation" title="Enteric fermentation">enteric fermentation</a>, particularly in <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Cattle" title="Cattle">cattle</a>. <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Landfill_gas" title="Landfill gas">Landfill gas</a> is created by decomposition of waste in <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Landfill" title="Landfill">landfill</a> sites. Excluding <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Water_vapor" title="Water vapor">water vapor</a>, about half of landfill gas is methane and most of the rest is <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Carbon_dioxide" title="Carbon dioxide">carbon dioxide</a>, with small amounts of <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Nitrogen" title="Nitrogen">nitrogen</a>, <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Oxygen" title="Oxygen">oxygen</a>, and <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Hydrogen" title="Hydrogen">hydrogen</a>, and variable trace amounts of <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Hydrogen_sulfide" title="Hydrogen sulfide">hydrogen sulfide</a> and <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Siloxane" title="Siloxane">siloxanes</a>. If the gas is not removed, the pressure may get so high that it works its way to the surface, causing damage to the landfill structure, unpleasant odor, vegetation die-off, and an <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Explosion" title="Explosion">explosion</a> hazard. The gas can be vented to the atmosphere, <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Gas_flare" title="Gas flare">flared</a> or burned to produce <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Electricity" title="Electricity">electricity</a> or <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Heat" title="Heat">heat</a>. Biogas can also be produced by separating <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Organic_material" class="mw-redirect" title="Organic material">organic materials</a> from waste that otherwise goes to landfills. This method is more efficient than just capturing the landfill gas it produces. <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Anaerobic_lagoon" title="Anaerobic lagoon">Anaerobic lagoons</a> produce biogas from manure, while biogas reactors can be used for manure or plant parts. Like landfill gas, biogas is mostly methane and carbon dioxide, with small amounts of nitrogen, oxygen and hydrogen. However, with the exception of pesticides, there are usually lower levels of contaminants. Landfill gas cannot be distributed through utility natural gas pipelines unless it is cleaned up to less than 3 per cent CO2, and a few parts per million H 2S, because CO2 and H 2S corrode the pipelines.<a href="#cite_note-26">[26]</a> The presence of CO2 will lower the energy level of the gas below requirements for the pipeline.[<a href="/web/20160627225612/https://en.wikipedia.org/wiki/Wikipedia:Please_clarify" title="Wikipedia:Please clarify">clarification needed</a>] Siloxanes in the gas will form deposits in gas burners and need to be removed prior to entry into any gas distribution or transmission system. Consequently, it may be more economical to burn the gas on site or within a short distance of the landfill using a dedicated pipeline. Water vapor is often removed, even if the gas is burned on site. If low temperatures condense water out of the gas, <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Siloxanes" class="mw-redirect" title="Siloxanes">siloxanes</a> can be lowered as well because they tend to condense out with the water vapor. Other non-methane components may also be removed to meet <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Emission_standard" title="Emission standard">emission standards</a>, to prevent fouling of the equipment or for environmental considerations. Co-firing landfill gas with natural gas improves combustion, which lowers emissions. Biogas, and especially landfill gas, are already used in some areas, but their use could be greatly expanded. Experimental systems were being proposed[<a href="/web/20160627225612/https://en.wikipedia.org/wiki/Wikipedia:Manual_of_Style/Dates_and_numbers#Chronological_items" title="Wikipedia:Manual of Style/Dates and numbers">when?</a>] for use in parts of <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Hertfordshire" title="Hertfordshire">Hertfordshire</a>, UK, and <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Lyon" title="Lyon">Lyon</a> in France.[<a href="/web/20160627225612/https://en.wikipedia.org/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed">citation needed</a>] Using materials that would otherwise generate no income, or even cost money to get rid of, improves the profitability and energy balance of biogas production. Gas generated in <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Sewage_treatment" title="Sewage treatment">sewage treatment</a> plants is commonly used to generate electricity. For example, the Hyperion sewage plant in Los Angeles burns 8 million cubic feet (230,000 m3) of gas per day to generate power<a href="#cite_note-27">[27]</a> New York City utilizes gas to run equipment in the sewage plants, to generate electricity, and in boilers.<a href="#cite_note-28">[28]</a> Using sewage gas to make electricity is not limited to large cities. The city of <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Bakersfield,_California" title="Bakersfield, California">Bakersfield, California</a>, uses <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Cogeneration" title="Cogeneration">cogeneration</a> at its sewer plants.<a href="#cite_note-29">[29]</a> California has 242 sewage wastewater treatment plants, 74 of which have installed anaerobic digesters. The total biopower generation from the 74 plants is about 66 MW.<a href="#cite_note-30">[30]</a> <div class="thumb tright"> <div class="thumbinner" style="width:252px;"><a href="/web/20160627225612/https://en.wikipedia.org/wiki/File:NaturalGasProcessingPlant.jpg" class="image"><img alt="" src="//web.archive.org/web/20160627225612im_/https://upload.wikimedia.org/wikipedia/commons/thumb/f/f3/NaturalGasProcessingPlant.jpg/250px-NaturalGasProcessingPlant.jpg" width="250" height="165" class="thumbimage" srcset="//web.archive.org/web/20160627225612im_/https://upload.wikimedia.org/wikipedia/commons/f/f3/NaturalGasProcessingPlant.jpg 1.5x, //web.archive.org/web/20160627225612im_/https://upload.wikimedia.org/wikipedia/commons/f/f3/NaturalGasProcessingPlant.jpg 2x" data-file-width="299" data-file-height="197"/></a> <div class="thumbcaption"> <div class="magnify"><a href="/web/20160627225612/https://en.wikipedia.org/wiki/File:NaturalGasProcessingPlant.jpg" class="internal" title="Enlarge"></a></div> The McMahon natural gas processing plant in <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Taylor,_British_Columbia" title="Taylor, British Columbia">Taylor, British Columbia</a>, <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Canada" title="Canada">Canada</a>.<a href="#cite_note-31">[31]</a></div> </div> </div> <h3>Crystallized natural gas — hydrates[<a href="/web/20160627225612/https://en.wikipedia.org/w/index.php?title=Natural_gas&action=edit&section=6" title="Edit section: Crystallized natural gas — hydrates">edit</a>]</h3> Huge quantities of natural gas (primarily methane) exist in the form of <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Methane_clathrate" title="Methane clathrate">hydrates</a> under sediment on offshore continental shelves and on land in arctic regions that experience <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Permafrost" title="Permafrost">permafrost</a>, such as those in <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Siberia" title="Siberia">Siberia</a>. Hydrates require a combination of high pressure and low temperature to form. In 2010, the cost of extracting natural gas from crystallized natural gas was estimated to 100–200 per cent the cost of extracting natural gas from conventional sources, and even higher from offshore deposits.<a href="#cite_note-32">[32]</a> In 2013, Japan Oil, Gas and Metals National Corporation (JOGMEC) announced that they had recovered commercially relevant quantities of natural gas from methane hydrate.<a href="#cite_note-33">[33]</a> <h2>Natural gas processing[<a href="/web/20160627225612/https://en.wikipedia.org/w/index.php?title=Natural_gas&action=edit&section=7" title="Edit section: Natural gas processing">edit</a>]</h2> <div role="note" class="hatnote relarticle mainarticle">Main article: <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Natural_gas_processing" class="mw-redirect" title="Natural gas processing">Natural gas processing</a></div> The image below is a schematic <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Process_flow_diagram" title="Process flow diagram">block flow diagram</a> 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 <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Pentanes" title="Pentanes">pentanes</a> +).<a href="#cite_note-34">[34]</a><a href="#cite_note-35">[35]</a><a href="#cite_note-36">[36]</a><a href="#cite_note-37">[37]</a><a href="#cite_note-38">[38]</a> <div class="center"> <div class="thumb tnone"> <div class="thumbinner" style="width:746px;"><a href="/web/20160627225612/https://en.wikipedia.org/wiki/File:NatGasProcessing.svg" class="image"><img alt="" src="//web.archive.org/web/20160627225612im_/https://upload.wikimedia.org/wikipedia/commons/thumb/0/0a/NatGasProcessing.svg/744px-NatGasProcessing.svg.png" width="744" height="524" class="thumbimage" data-file-width="744" data-file-height="524"/></a> <div class="thumbcaption">Schematic flow diagram of a typical natural gas processing plant.</div> </div> </div> </div> <h2>Depletion[<a href="/web/20160627225612/https://en.wikipedia.org/w/index.php?title=Natural_gas&action=edit&section=8" title="Edit section: Depletion">edit</a>]</h2> <div role="note" class="hatnote relarticle mainarticle">Main article: <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Gas_depletion" title="Gas depletion">Gas depletion</a></div> Natural gas production in the U.S. reached a peak in 1973, and went over a second lower peak in 2001, but recently has peaked again and is continuing to rise.<a href="#cite_note-39">[39]</a> <a href="#cite_note-40">[40]</a> <h2>Uses[<a href="/web/20160627225612/https://en.wikipedia.org/w/index.php?title=Natural_gas&action=edit&section=9" title="Edit section: Uses">edit</a>]</h2> Natural gas is primarily used in the northern hemisphere. North America and Europe are major consumers. <h3>Mid-stream natural gas[<a href="/web/20160627225612/https://en.wikipedia.org/w/index.php?title=Natural_gas&action=edit&section=10" title="Edit section: Mid-stream natural gas">edit</a>]</h3> Natural gas flowing in the distribution lines and at the natural gas well head are often used to power natural gas powered engines. These engines rotate compressors to facilitate the natural gas transmission. These compressors are required in the mid-stream line to pressurize and to re-pressurize the natural gas in the transmission line as the gas travels. The natural gas transmission lines extend to the natural gas processing plant or unit which removes the higher molecular weighted natural gas hydrocarbons to produce a <a href="/web/20160627225612/https://en.wikipedia.org/wiki/British_thermal_unit" title="British thermal unit">British thermal unit</a> (BTU) value between 950 and 1050 BTUs. The processed natural gas may then be used for residential, commercial and industrial uses. Often mid-stream and well head gases require removal of many of the various hydrocarbon species contained within the natural gas. Some of these gases include <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Heptane" title="Heptane">heptane</a>, <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Pentane" title="Pentane">pentane</a>, <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Propane" title="Propane">propane</a> and other hydrocarbons with molecular weights above <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Methane" title="Methane">Methane</a> (CH4) to produce a natural gas fuel which is used to operate the natural gas engines for further pressurized transmission. Typically, natural gas compressors require 950 to 1050 BTU per cubic foot to operate at the natural gas engines rotational name plate specifications. Several methods are used to remove these higher molecular weighted gases for use at the natural gas engine. A few technologies are as follows: <ul> <li><a href="/web/20160627225612/https://en.wikipedia.org/wiki/Joule%E2%80%93Thomson_effect" title="Joule–Thomson effect">Joule–Thomson skid</a></li> <li><a href="/web/20160627225612/https://en.wikipedia.org/wiki/Cryogenic" class="mw-redirect" title="Cryogenic">Cryogenic</a> or <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Chiller" title="Chiller">chiller</a> system</li> <li><a href="/web/20160627225612/https://en.wikipedia.org/wiki/Chemical" class="mw-redirect" title="Chemical">Chemical</a> <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Enzymology" class="mw-redirect" title="Enzymology">enzymology</a> system<a href="#cite_note-41">[41]</a></li> </ul> <h3>Power generation[<a href="/web/20160627225612/https://en.wikipedia.org/w/index.php?title=Natural_gas&action=edit&section=11" title="Edit section: Power generation">edit</a>]</h3> Natural gas is a major source of <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Electricity_generation" title="Electricity generation">electricity generation</a> through the use of <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Cogeneration" title="Cogeneration">cogeneration</a>, <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Gas_turbine" title="Gas turbine">gas turbines</a> and <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Steam_turbine" title="Steam turbine">steam turbines</a>. Natural gas is also well suited for a combined use in association with <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Renewable_energy" title="Renewable energy">renewable energy</a> sources such as wind or <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Solar_energy" title="Solar energy">solar</a><a href="#cite_note-42">[42]</a> and for alimenting <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Load_profile" title="Load profile">peak-load</a> power stations functioning in tandem with <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Hydroelectric" class="mw-redirect" title="Hydroelectric">hydroelectric</a> plants. Most grid <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Peaking_power_plant" title="Peaking power plant">peaking power plants</a> and some off-grid <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Engine-generator" title="Engine-generator">engine-generators</a> use natural gas. Particularly high efficiencies can be achieved through combining gas turbines with a steam turbine in <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Combined_cycle" title="Combined cycle">combined cycle</a> mode. Natural gas burns more cleanly than other <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Hydrocarbon_fuel" class="mw-redirect" title="Hydrocarbon fuel">hydrocarbon fuels</a>, such as oil and coal, and produces less carbon dioxide per unit of energy released. For transportation, burning natural gas produces about 30 percent less <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Carbon_dioxide" title="Carbon dioxide">carbon dioxide</a> than burning <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Petroleum" title="Petroleum">petroleum</a>. For an equivalent amount of heat, burning natural gas produces about 45 percent less carbon dioxide than burning <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Coal" title="Coal">coal</a> for power.<a href="#cite_note-gasdotorg-43">[43]</a> The US <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Energy_Information_Administration" title="Energy Information Administration">Energy Information Administration</a> reports the following emissions in million <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Tonne" title="Tonne">metric tons</a> of carbon dioxide in the world for 2012:<a href="#cite_note-44">[44]</a> <ul> <li>Natural gas: 6,799</li> <li>Petroleum: 11,695</li> <li>Coal: 13,787</li> </ul> Coal-fired electric power generation emits around 2,000 pounds of carbon dioxide for every megawatt hour generated, which is almost double the carbon dioxide released by a natural gas-fired electric plant per megawatt hour generated.<a href="#cite_note-45">[45]</a> Because of this higher carbon efficiency of natural gas generation, as the fuel mix in the United States has changed to reduce coal and increase natural gas generation, carbon dioxide emissions have unexpectedly fallen. Those measured in the first quarter of 2012 were the lowest of any recorded for the first quarter of any year since 1992.<a href="#cite_note-46">[46]</a> Combined cycle power generation using natural gas is currently the cleanest available source of power using hydrocarbon fuels, and this technology is widely and increasingly used as natural gas can be obtained at increasingly reasonable costs. <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Fuel_cell" title="Fuel cell">Fuel cell</a> technology may eventually provide cleaner options for converting natural gas into electricity, but as yet it is not price-competitive. Locally produced electricity and heat using natural gas powered Combined Heat and Power plant (CHP or <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Cogeneration" title="Cogeneration">Cogeneration</a> plant) is considered energy efficient and a rapid way to cut carbon emissions.<a href="#cite_note-Alfagy-47">[47]</a> Natural gas power plants are increasing in popularity and generate 22% of the worlds total electricity. Approximately half as much as generated with coal.<a href="#cite_note-48">[48]</a> <h3>Domestic use[<a href="/web/20160627225612/https://en.wikipedia.org/w/index.php?title=Natural_gas&action=edit&section=12" title="Edit section: Domestic use">edit</a>]</h3> Natural gas dispensed in a residential setting can generate temperatures in excess of 1100 °C (2000 °F) making it a powerful domestic cooking and heating fuel.<a href="#cite_note-49">[49]</a> In much of the developed world it is supplied through pipes to homes, where it is used for many purposes including ranges and ovens, gas-heated <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Clothes_dryer" title="Clothes dryer">clothes dryers</a>, <a href="/web/20160627225612/https://en.wikipedia.org/wiki/HVAC" title="HVAC">heating</a>/<a href="/web/20160627225612/https://en.wikipedia.org/wiki/Air_conditioning" title="Air conditioning">cooling</a>, and <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Central_heating" title="Central heating">central heating</a>. Heaters in homes and other buildings may include boilers, <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Furnace" title="Furnace">furnaces</a>, and <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Water_heater" class="mw-redirect" title="Water heater">water heaters</a>. Both North America and Europe are major consumers of natural gas. Boilers use low pressure, usually 6 to 7 <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Inch_of_water" title="Inch of water">inches of water</a> (6" to 7" WC), which is about 0.25 psig. The pressures in the supply lines under the streets vary, either utilization pressure (UP, the aforementioned 6" to 7" WC) or elevated pressure (EP), which may be anywhere from 1 psig to 120 psig. Systems using EP have a <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Pressure_regulator" title="Pressure regulator">regulator</a> at the service entrance to step down the pressure to UP. In the US <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Compressed_natural_gas" title="Compressed natural gas">Compressed natural gas</a> (CNG) is used in <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Rural" class="mw-redirect" title="Rural">rural</a> homes without connections to <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Plumbing" title="Plumbing">piped</a>-in <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Public_utility" title="Public utility">public utility</a> services, or with portable <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Grill_(cooking)" class="mw-redirect" title="Grill (cooking)">grills</a>.[<a href="/web/20160627225612/https://en.wikipedia.org/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed">citation needed</a>] Natural gas is also supplied by independent natural gas suppliers through <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Natural_Gas_Choice" title="Natural Gas Choice">Natural Gas Choice</a> programs throughout the United States. However, as CNG costs more than <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Liquefied_petroleum_gas" title="Liquefied petroleum gas">LPG</a>, LPG (propane) is the dominant source of rural gas. <div class="thumb tright"> <div class="thumbinner" style="width:222px;"><a href="/web/20160627225612/https://en.wikipedia.org/wiki/File:WMATA_3006.jpg" class="image"><img alt="" src="//web.archive.org/web/20160627225612im_/https://upload.wikimedia.org/wikipedia/commons/thumb/0/06/WMATA_3006.jpg/220px-WMATA_3006.jpg" width="220" height="165" class="thumbimage" srcset="//web.archive.org/web/20160627225612im_/https://upload.wikimedia.org/wikipedia/commons/thumb/0/06/WMATA_3006.jpg/330px-WMATA_3006.jpg 1.5x, //web.archive.org/web/20160627225612im_/https://upload.wikimedia.org/wikipedia/commons/thumb/0/06/WMATA_3006.jpg/440px-WMATA_3006.jpg 2x" data-file-width="1024" data-file-height="768"/></a> <div class="thumbcaption"> <div class="magnify"><a href="/web/20160627225612/https://en.wikipedia.org/wiki/File:WMATA_3006.jpg" class="internal" title="Enlarge"></a></div> A <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Washington,_D.C." title="Washington, D.C.">Washington, D.C.</a> <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Metrobus_(Washington,_D.C.)" title="Metrobus (Washington, D.C.)">Metrobus</a>, which runs on natural gas.</div> </div> </div> <h3>Transportation[<a href="/web/20160627225612/https://en.wikipedia.org/w/index.php?title=Natural_gas&action=edit&section=13" title="Edit section: Transportation">edit</a>]</h3> CNG is a cleaner and also cheaper alternative to other <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Automobile" class="mw-redirect" title="Automobile">automobile</a> fuels such as <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Gasoline" title="Gasoline">gasoline</a> (petrol) and <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Diesel_fuel" title="Diesel fuel">diesel</a>. By the end of 2012 there were 17.25 million <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Natural_gas_vehicle" title="Natural gas vehicle">natural gas vehicles</a> worldwide, led by <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Iran" title="Iran">Iran</a> (3.3 million), <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Pakistan" title="Pakistan">Pakistan</a> (3.1 million), <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Argentina" title="Argentina">Argentina</a> (2.18 million), <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Brazil" title="Brazil">Brazil</a> (1.73 million), <a href="/web/20160627225612/https://en.wikipedia.org/wiki/India" title="India">India</a> (1.5 million), and <a href="/web/20160627225612/https://en.wikipedia.org/wiki/China" title="China">China</a> (1.5 million).<a href="#cite_note-50">[50]</a> The 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 <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Compression_ratio" title="Compression ratio">compression ratio</a> 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 <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Octane_number" class="mw-redirect" title="Octane number">octane number</a> of 120–130.<a href="#cite_note-51">[51]</a> <a href="#cite_note-52">[52]</a> Besides use in road vehicles, it is also used in aerial vehicles. Compressed natural gas has been used in some aircraft like the <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Aviat_Aircraft" class="mw-redirect" title="Aviat Aircraft">Aviat Aircraft</a> Husky 200 CNG<a href="#cite_note-53">[53]</a><a href="#cite_note-54">[54]</a><a href="#cite_note-55">[55]</a> and the Chromarat VX-1 KittyHawk<a href="#cite_note-56">[56]</a> LNG is also being used in aircraft. <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Russia" title="Russia">Russian</a> aircraft manufacturer <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Tupolev" title="Tupolev">Tupolev</a> for instance is running a development program to produce LNG- and <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Hydrogen" title="Hydrogen">hydrogen</a>-powered aircraft.<a href="#cite_note-57">[57]</a> The program has been running since the mid-1970s, and seeks to develop LNG and hydrogen variants of the <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Tupolev_Tu-204" title="Tupolev Tu-204">Tu-204</a> and <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Tupolev_Tu-334" title="Tupolev Tu-334">Tu-334</a> passenger aircraft, and also the <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Tupolev_Tu-330" title="Tupolev Tu-330">Tu-330</a> cargo aircraft. It claims that at current market prices, an LNG-powered aircraft would cost 5,000 <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Rouble" class="mw-redirect" title="Rouble">roubles</a> (~ US$218/ £112) less to operate per ton, roughly equivalent to 60 per cent, with considerable reductions to <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Carbon_monoxide" title="Carbon monoxide">carbon monoxide</a>, <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Hydrocarbon" title="Hydrocarbon">hydrocarbon</a> and <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Nitrogen_oxide" title="Nitrogen oxide">nitrogen oxide</a> emissions. The advantages of liquid methane as a jet engine fuel are that it has more specific energy than the standard <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Kerosene" title="Kerosene">kerosene</a> mixes do and that its low temperature can help cool the air which the engine compresses for greater volumetric efficiency, in effect replacing an <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Intercooler" title="Intercooler">intercooler</a>. Alternatively, it can be used to lower the temperature of the exhaust. <h3>Fertilizers[<a href="/web/20160627225612/https://en.wikipedia.org/w/index.php?title=Natural_gas&action=edit&section=14" title="Edit section: Fertilizers">edit</a>]</h3> Natural gas is a major feedstock for the production of <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Ammonia" title="Ammonia">ammonia</a>, via the <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Haber_process" title="Haber process">Haber process</a>, for use in <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Fertilizer" title="Fertilizer">fertilizer</a> production. <h3>Hydrogen[<a href="/web/20160627225612/https://en.wikipedia.org/w/index.php?title=Natural_gas&action=edit&section=15" title="Edit section: Hydrogen">edit</a>]</h3> <div role="note" class="hatnote">See also: <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Industrial_gas" title="Industrial gas">Industrial gas</a></div> Natural gas can be used to produce <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Hydrogen" title="Hydrogen">hydrogen</a>, with one common method being the <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Hydrogen_reformer" class="mw-redirect" title="Hydrogen reformer">hydrogen reformer</a>. Hydrogen has many applications: it is a primary feedstock for the <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Chemical_industry" title="Chemical industry">chemical industry</a>, a hydrogenating agent, an important commodity for oil refineries, and the fuel source in <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Hydrogen_vehicle" title="Hydrogen vehicle">hydrogen vehicles</a>. <h3>Other[<a href="/web/20160627225612/https://en.wikipedia.org/w/index.php?title=Natural_gas&action=edit&section=16" title="Edit section: Other">edit</a>]</h3> Natural gas is also used in the manufacture of <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Textile" title="Textile">fabrics</a>, <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Glass" title="Glass">glass</a>, <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Steel" title="Steel">steel</a>, <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Plastic" title="Plastic">plastics</a>, <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Paint" title="Paint">paint</a>, and other products.[<a href="/web/20160627225612/https://en.wikipedia.org/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed">citation needed</a>] <h2>Storage and transport[<a href="/web/20160627225612/https://en.wikipedia.org/w/index.php?title=Natural_gas&action=edit&section=17" title="Edit section: Storage and transport">edit</a>]</h2> <div class="thumb tright"> <div class="thumbinner" style="width:172px;"><a href="/web/20160627225612/https://en.wikipedia.org/wiki/File:Polyethylene_gas_main.jpg" class="image"><img alt="" src="//web.archive.org/web/20160627225612im_/https://upload.wikimedia.org/wikipedia/commons/thumb/1/17/Polyethylene_gas_main.jpg/170px-Polyethylene_gas_main.jpg" width="170" height="235" class="thumbimage" srcset="//web.archive.org/web/20160627225612im_/https://upload.wikimedia.org/wikipedia/commons/thumb/1/17/Polyethylene_gas_main.jpg/255px-Polyethylene_gas_main.jpg 1.5x, //web.archive.org/web/20160627225612im_/https://upload.wikimedia.org/wikipedia/commons/thumb/1/17/Polyethylene_gas_main.jpg/340px-Polyethylene_gas_main.jpg 2x" data-file-width="844" data-file-height="1166"/></a> <div class="thumbcaption"> <div class="magnify"><a href="/web/20160627225612/https://en.wikipedia.org/wiki/File:Polyethylene_gas_main.jpg" class="internal" title="Enlarge"></a></div> <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Polyethylene" title="Polyethylene">Polyethylene</a> plastic <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Gas_main" class="mw-redirect" title="Gas main">main</a> being placed in a <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Trench" title="Trench">trench</a>.</div> </div> </div> Because of its low density, it is not easy to store natural gas or to transport it by vehicle. Natural gas <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Pipeline_transport" title="Pipeline transport">pipelines</a> are impractical across <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Ocean" title="Ocean">oceans</a>, since the gas needs to be cooled down and compressed, as the friction in the pipeline causes the gas to heat up. Many <a href="/web/20160627225612/https://en.wikipedia.org/wiki/List_of_natural_gas_pipelines#North_America" title="List of natural gas pipelines">existing pipelines in America</a> are close to reaching their capacity, prompting some politicians representing northern states to speak of potential shortages. The large trade cost imply that natural gas markets are globally much less integrated, causing significant price differences across countries. In Western <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Europe" title="Europe">Europe</a>, the gas pipeline network is already dense.<a href="#cite_note-58">[58]</a> New pipelines are planned or under construction in Eastern Europe and between gas fields in <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Russia" title="Russia">Russia</a>, <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Near_East" title="Near East">Near East</a> and <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Northern_Africa" class="mw-redirect" title="Northern Africa">Northern Africa</a> and Western Europe. See also <a href="/web/20160627225612/https://en.wikipedia.org/wiki/List_of_natural_gas_pipelines" title="List of natural gas pipelines">List of natural gas pipelines</a>. <a href="/web/20160627225612/https://en.wikipedia.org/wiki/LNG_carrier" title="LNG carrier">LNG carriers</a> transport <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Liquefied_natural_gas" title="Liquefied natural gas">liquefied natural gas</a> (LNG) across oceans, while <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Tank_truck" title="Tank truck">tank trucks</a> can carry liquefied or <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Compressed_natural_gas" title="Compressed natural gas">compressed natural gas</a> (CNG) over shorter distances. Sea transport using <a href="/web/20160627225612/https://en.wikipedia.org/wiki/CNG_carrier" title="CNG carrier">CNG carrier</a> ships that are now under development may be competitive with LNG transport in specific conditions. Gas is turned into liquid at a <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Liquefaction_of_gases" title="Liquefaction of gases">liquefaction</a> plant, and is returned to gas form at <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Gasification" title="Gasification">regasification</a> plant at the <a href="/web/20160627225612/https://en.wikipedia.org/w/index.php?title=LNG_terminal&action=edit&redlink=1" class="new" title="LNG terminal (page does not exist)">terminal</a>. 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 4,000 km (2,485 mi) over land and approximately half that distance offshore. CNG is transported at high pressure, typically above 200 <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Bar_(unit)" title="Bar (unit)">bars</a>. 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. <div class="thumb tright"> <div class="thumbinner" style="width:252px;"><a href="/web/20160627225612/https://en.wikipedia.org/wiki/File:Manlove_gas_storage_facility_crop.jpg" class="image"><img alt="" src="//web.archive.org/web/20160627225612im_/https://upload.wikimedia.org/wikipedia/commons/thumb/8/8a/Manlove_gas_storage_facility_crop.jpg/250px-Manlove_gas_storage_facility_crop.jpg" width="250" height="159" class="thumbimage" srcset="//web.archive.org/web/20160627225612im_/https://upload.wikimedia.org/wikipedia/commons/thumb/8/8a/Manlove_gas_storage_facility_crop.jpg/375px-Manlove_gas_storage_facility_crop.jpg 1.5x, //web.archive.org/web/20160627225612im_/https://upload.wikimedia.org/wikipedia/commons/thumb/8/8a/Manlove_gas_storage_facility_crop.jpg/500px-Manlove_gas_storage_facility_crop.jpg 2x" data-file-width="2363" data-file-height="1506"/></a> <div class="thumbcaption"> <div class="magnify"><a href="/web/20160627225612/https://en.wikipedia.org/wiki/File:Manlove_gas_storage_facility_crop.jpg" class="internal" title="Enlarge"></a></div> <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Peoples_Gas" class="mw-redirect" title="Peoples Gas">Peoples Gas</a> Manlove Field <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Natural_gas_storage" title="Natural gas storage">natural gas storage</a> area in <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Newcomb_Township,_Champaign_County,_Illinois" title="Newcomb Township, Champaign County, Illinois">Newcomb Township, Champaign County, Illinois</a>. 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).</div> </div> </div> In the past, the natural gas which was recovered in the course of recovering <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Petroleum" title="Petroleum">petroleum</a> could not be profitably sold, and was simply burned at the oil field in a process known as <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Gas_flare" title="Gas flare">flaring</a>. Flaring is now illegal in many countries.<a href="#cite_note-59">[59]</a> 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-<a href="//web.archive.org/web/20160627225612/https://en.wiktionary.org/wiki/inject" class="extiw" title="wiktionary:inject">injected</a> 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. A recent study suggests that the expansion of shale gas production in the U.S. 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 U.S. manufacturing exports has almost tripled its energy content between 1996 and 2012.<a href="#cite_note-60">[60]</a> A "master gas system" was invented in <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Saudi_Arabia" title="Saudi Arabia">Saudi Arabia</a> in the late 1970s, ending any necessity for flaring. Satellite observation, however, shows that flaring<a href="#cite_note-61">[61]</a> and venting<a href="#cite_note-62">[62]</a> are still practiced in some gas-extracting countries. Natural gas is used to generate electricity and heat for <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Desalination" title="Desalination">desalination</a>. 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 inside depleted gas reservoirs from previous gas wells, <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Salt_domes" class="mw-redirect" title="Salt domes">salt domes</a>, or in tanks as <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Liquefied_natural_gas" title="Liquefied natural gas">liquefied natural gas</a>. 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 per cent of the worldwide extraction, access to natural gas has become an important issue in international politics, and countries vie for control of pipelines.<a href="#cite_note-63">[63]</a> In the first decade of the 21st century, <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Gazprom" title="Gazprom">Gazprom</a>, the state-owned energy company in Russia, engaged in disputes with <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Ukraine" title="Ukraine">Ukraine</a> and <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Belarus" title="Belarus">Belarus</a> over the price of natural gas, which have created concerns that gas deliveries to parts of Europe could be cut off for political reasons.<a href="#cite_note-64">[64]</a> The United States is preparing to export natural gas.<a href="#cite_note-65">[65]</a> <a href="/web/20160627225612/https://en.wikipedia.org/wiki/FLNG" class="mw-redirect" title="FLNG">Floating Liquefied Natural Gas (FLNG)</a> is an innovative technology designed to enable the development of offshore gas resources that would otherwise remain untapped because due to environmental or economic factors it is nonviable to develop them via a land-based LNG operation. FLNG technology also provides a number of environmental and economic advantages: <ul> <li>Environmental – 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.<a href="#cite_note-66">[66]</a> 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.</li> <li>Economic – 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.<a href="#cite_note-67">[67]</a></li> </ul> Many gas and oil companies are considering the economic and environmental benefits of <a href="/web/20160627225612/https://en.wikipedia.org/wiki/FLNG" class="mw-redirect" title="FLNG">Floating Liquefied Natural Gas (FLNG)</a>. There are currently projects underway to construct five FLNG facilities. <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Petronas" title="Petronas">Petronas</a> is close to completion on their FLNG-1<a href="#cite_note-68">[68]</a> at <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Daewoo_Shipbuilding_and_Marine_Engineering" class="mw-redirect" title="Daewoo Shipbuilding and Marine Engineering">Daewoo Shipbuilding and Marine Engineering</a> and are underway<a href="#cite_note-69">[69]</a> on their FLNG-2 project at <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Samsung_Heavy_Industries" title="Samsung Heavy Industries">Samsung Heavy Industries</a>. <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Shell_Prelude" class="mw-redirect" title="Shell Prelude">Shell Prelude</a> is due to start production 2017 and the <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Browse_LNG" title="Browse LNG">Browse LNG</a> project has completed <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Front-end_loading" title="Front-end loading">FEED</a> with final investment decisions expected in mid-2016.<a href="#cite_note-70">[70]</a> <h2>Environmental effects[<a href="/web/20160627225612/https://en.wikipedia.org/w/index.php?title=Natural_gas&action=edit&section=18" title="Edit section: Environmental effects">edit</a>]</h2> <div role="note" class="hatnote">See also: <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Environmental_impact_of_the_energy_industry" title="Environmental impact of the energy industry">Environmental impact of the energy industry</a></div> <h3>Effect of natural gas release[<a href="/web/20160627225612/https://en.wikipedia.org/w/index.php?title=Natural_gas&action=edit&section=19" title="Edit section: Effect of natural gas release">edit</a>]</h3> <div role="note" class="hatnote">See also: <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Atmospheric_methane" title="Atmospheric methane">Atmospheric methane</a></div> Natural gas is mainly composed of methane. After release to the atmosphere it is removed by gradual oxidation to carbon dioxide and water by hydroxyl radicals (·OH) formed in the troposphere or stratosphere, giving the overall chemical reaction CH4 + 2O2→ CO2 + 2H2O.<a href="#cite_note-Manahan-71">[71]</a><a href="#cite_note-NASA_GISS-72">[72]</a> While the lifetime of atmospheric methane is relatively short when compared to carbon dioxide,<a href="#cite_note-Ny_times-73">[73]</a> with a half-life of about 7 years,<a href="#cite_note-74">[74]</a> 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 more potent <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Greenhouse_gas" title="Greenhouse gas">greenhouse gas</a> than carbon dioxide due to the greater <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Global-warming_potential" class="mw-redirect" title="Global-warming potential">global-warming potential</a> of methane.<a href="#cite_note-IPCC-75">[75]</a> But because when it is burned, it produces more water than carbon dioxide by mole, in contrast to coal which produces mainly carbon dioxide, it produces only about half the carbon dioxide per kilowatt-hour that coal does. Current estimates by the EPA place global emissions of methane at 85 billion cubic metres (3.0×10<s style="display:none">^</s>12 cu ft) annually,<a href="#cite_note-Ny_times-73">[73]</a> or 3.2 per cent of global production.<a href="#cite_note-76">[76]</a> Direct emissions of methane represented 14.3 per cent by volume of all global anthropogenic greenhouse gas emissions in 2004.<a href="#cite_note-77">[77]</a> During extraction, storage, transportation, and distribution, natural gas is known to leak into the atmosphere, particularly during the extraction process. A Cornell University study in 2011 demonstrated that the leak rate of methane may be high enough to jeopardize its global warming advantage over coal.<a href="#cite_note-78">[78]</a> This study was criticized later for its over-estimation of methane leakage values.<a href="#cite_note-Response_to_Cornell-79">[79]</a> Preliminary results of some air sampling from airplanes done by the National Oceanic and Atmospheric Administration indicated higher-than-estimated methane releases by gas wells in some areas,<a href="#cite_note-Business_week-80">[80]</a> but the overall results showed methane emissions in line with previous EPA estimates<a href="#cite_note-81">[81]</a> Natural gas extraction also releases an isotope of <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Radon" title="Radon">radon</a>, ranging in activity from 5 to 200,000 <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Becquerels" class="mw-redirect" title="Becquerels">becquerels</a> per cubic meter of gas.<a href="#cite_note-82">[82]</a> <h3>CO2 emissions[<a href="/web/20160627225612/https://en.wikipedia.org/w/index.php?title=Natural_gas&action=edit&section=20" title="Edit section: CO2 emissions">edit</a>]</h3> Natural gas is often described as the cleanest fossil <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Fuel" title="Fuel">fuel</a>. It produces about 29% and 44% less carbon dioxide per <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Joule" title="Joule">joule</a> delivered than oil and coal respectively,<a href="#cite_note-gasdotorg-43">[43]</a> and potentially fewer pollutants than other hydrocarbon fuels.<a href="#cite_note-Natural_gas.org_environment-83">[83]</a> However, in absolute terms, it comprises a substantial percentage of human <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Carbon_emission" class="mw-redirect" title="Carbon emission">carbon emissions</a>, and this contribution is projected to grow. According to the <a href="/web/20160627225612/https://en.wikipedia.org/wiki/IPCC_Fourth_Assessment_Report" title="IPCC Fourth Assessment Report">IPCC Fourth Assessment Report</a>, in 2004, natural gas produced about 5.3 billion tons a year of CO2 emissions, while coal and oil produced 10.6 and 10.2 billion tons respectively. According to an updated version of the <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Special_Report_on_Emissions_Scenarios#B2" title="Special Report on Emissions Scenarios">Special Report on Emissions Scenario</a> by 2030, natural gas would be the source of 11 billion tons a year, with coal and oil now 8.4 and 17.2 billion respectively because demand is increasing 1.9 percent a year. <h3>Other pollutants[<a href="/web/20160627225612/https://en.wikipedia.org/w/index.php?title=Natural_gas&action=edit&section=21" title="Edit section: Other pollutants">edit</a>]</h3> Natural gas produces far lower amounts of <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Sulfur_dioxide" title="Sulfur dioxide">sulfur dioxide</a> and <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Nitrous_oxide" title="Nitrous oxide">nitrous oxides</a> than other fossil fuels.<a href="#cite_note-84">[84]</a> The other pollutants due to natural gas combustion are listed below<a href="#cite_note-Natural_gas.org_environment-83">[83]</a><a href="#cite_note-85">[85]</a> in pounds per billion <a href="/web/20160627225612/https://en.wikipedia.org/wiki/BTU" class="mw-redirect" title="BTU">BTU</a>: <ul> <li><a href="/web/20160627225612/https://en.wikipedia.org/wiki/Carbon_monoxide" title="Carbon monoxide">Carbon monoxide</a> – 40</li> <li>Sulfur dioxide – 1</li> <li>Nitrogen oxide – 92</li> <li>Particulates – 7</li> </ul> <h2>Safety concerns[<a href="/web/20160627225612/https://en.wikipedia.org/w/index.php?title=Natural_gas&action=edit&section=22" title="Edit section: Safety concerns">edit</a>]</h2> <div class="thumb tright"> <div class="thumbinner" style="width:222px;"><a href="/web/20160627225612/https://en.wikipedia.org/wiki/File:Gas_pipeline_odourant_injection_facility.JPG" class="image"><img alt="" src="//web.archive.org/web/20160627225612im_/https://upload.wikimedia.org/wikipedia/commons/thumb/d/d5/Gas_pipeline_odourant_injection_facility.JPG/220px-Gas_pipeline_odourant_injection_facility.JPG" width="220" height="165" class="thumbimage" srcset="//web.archive.org/web/20160627225612im_/https://upload.wikimedia.org/wikipedia/commons/thumb/d/d5/Gas_pipeline_odourant_injection_facility.JPG/330px-Gas_pipeline_odourant_injection_facility.JPG 1.5x, //web.archive.org/web/20160627225612im_/https://upload.wikimedia.org/wikipedia/commons/thumb/d/d5/Gas_pipeline_odourant_injection_facility.JPG/440px-Gas_pipeline_odourant_injection_facility.JPG 2x" data-file-width="2048" data-file-height="1536"/></a> <div class="thumbcaption"> <div class="magnify"><a href="/web/20160627225612/https://en.wikipedia.org/wiki/File:Gas_pipeline_odourant_injection_facility.JPG" class="internal" title="Enlarge"></a></div> A pipeline odorant injection station</div> </div> </div> <h3>Production[<a href="/web/20160627225612/https://en.wikipedia.org/w/index.php?title=Natural_gas&action=edit&section=23" title="Edit section: Production">edit</a>]</h3> Some gas fields yield <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Sour_gas" title="Sour gas">sour gas</a> containing <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Hydrogen_sulfide" title="Hydrogen sulfide">hydrogen sulfide</a> (H2S). This untreated gas is <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Toxic" class="mw-redirect" title="Toxic">toxic</a>. <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Amine_gas_treating" title="Amine gas treating">Amine gas treating</a>, an industrial scale process which removes <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Acidic" class="mw-redirect" title="Acidic">acidic</a> <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Gas" title="Gas">gaseous</a> components, is often used to remove hydrogen sulfide from natural gas.<a href="#cite_note-Processing_Natural_Gas-86">[86]</a> Extraction of natural gas (or oil) leads to decrease in pressure in the <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Oil_reservoir" class="mw-redirect" title="Oil reservoir">reservoir</a>. Such decrease in pressure in turn may result in <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Subsidence" title="Subsidence">subsidence</a>, sinking of the ground above. Subsidence may affect ecosystems, waterways, sewer and water supply systems, foundations, and so on.[<a href="/web/20160627225612/https://en.wikipedia.org/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed">citation needed</a>] <h3>Fracking[<a href="/web/20160627225612/https://en.wikipedia.org/w/index.php?title=Natural_gas&action=edit&section=24" title="Edit section: Fracking">edit</a>]</h3> <div role="note" class="hatnote relarticle mainarticle">Main article: <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Environmental_impact_of_hydraulic_fracturing" title="Environmental impact of hydraulic fracturing">Environmental impact of hydraulic fracturing</a></div> Releasing natural gas from subsurface porous rock formations may be accomplished by a process called <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Hydraulic_fracturing" title="Hydraulic fracturing">hydraulic fracturing</a> or "fracking". It's estimated that hydraulic fracturing will eventually account for nearly 70% of natural gas development in North America.<a href="#cite_note-87">[87]</a> Since the first commercial hydraulic fracturing operation in 1949, approximately one million wells have been hydraulically fractured in the United States.<a href="#cite_note-88">[88]</a> The production of natural gas from hydraulically fractured wells has utilized the technological developments of directional and horizontal drilling, which improved access to natural gas in tight rock formations.<a href="#cite_note-89">[89]</a> Strong growth in the production of unconventional gas from hydraulically fractured wells occurred between 2000-2012.<a href="#cite_note-90">[90]</a> 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 nearly 30 percent to 70 percent 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 <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Produced_water" title="Produced water">produced water</a> often has a high content of salt and other dissolved minerals that occur in the formation.<a href="#cite_note-91">[91]</a> 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 2000-2010, and nearly 3 million gallons for horizontal gas wells between 2000-2010.<a href="#cite_note-92">[92]</a> 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 <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Tight_gas" title="Tight gas">tight gas</a>.<a href="#cite_note-93">[93]</a> Fracking for shale gas, which is currently also known as a source of <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Unconventional_gas" title="Unconventional gas">unconventional gas</a>, 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.<a href="#cite_note-94">[94]</a> 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.<a href="#cite_note-95">[95]</a><a href="#cite_note-96">[96]</a> The decades in development of drilling technology for conventional and unconventional oil & gas production has not only improved access to natural gas in low-permeability reservoir rocks, but also posed significant adverse impacts on environmental and public health.<a href="#cite_note-97">[97]</a><a href="#cite_note-98">[98]</a><a href="#cite_note-99">[99]</a><a href="#cite_note-100">[100]</a><a href="#cite_note-101">[101]</a> The U.S. 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).<a href="#cite_note-102">[102]</a> 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.<a href="#cite_note-103">[103]</a> 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're mixed with, and would so heavily 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.<a href="#cite_note-104">[104]</a> <h3>Odor is Added[<a href="/web/20160627225612/https://en.wikipedia.org/w/index.php?title=Natural_gas&action=edit&section=25" title="Edit section: Odor is Added">edit</a>]</h3> In order to assist in detecting <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Leak" title="Leak">leaks</a>, a minute amount of <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Aroma_compound" title="Aroma compound">odorant</a> is added to the otherwise colorless and almost odorless gas used by consumers. The odor has been compared to the smell of rotten eggs, due to the added <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Tert-Butylthiol" title="Tert-Butylthiol">tert-Butylthiol</a> (t-butyl mercaptan). Sometimes a related compound, <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Tetrahydrothiophene" title="Tetrahydrothiophene">thiophane</a>, may be used in the mixture. Situations in which an odorant that is added to natural gas can be detected by analytical instrumentation, but cannot be properly detected by an observer with a normal sense of smell, have occurred in the natural gas industry. This is caused by odor masking, when one odorant overpowers the sensation of another. As of 2011, the industry is conducting research on the causes of odor masking.<a href="#cite_note-105">[105]</a> <h3>Risk of Explosion[<a href="/web/20160627225612/https://en.wikipedia.org/w/index.php?title=Natural_gas&action=edit&section=26" title="Edit section: Risk of Explosion">edit</a>]</h3> <div class="thumb tright"> <div class="thumbinner" style="width:222px;"><a href="/web/20160627225612/https://en.wikipedia.org/wiki/File:Fire_engines_in_Kiev,_Ukraine.JPG" class="image"><img alt="" src="//web.archive.org/web/20160627225612im_/https://upload.wikimedia.org/wikipedia/commons/thumb/9/9a/Fire_engines_in_Kiev%2C_Ukraine.JPG/220px-Fire_engines_in_Kiev%2C_Ukraine.JPG" width="220" height="165" class="thumbimage" srcset="//web.archive.org/web/20160627225612im_/https://upload.wikimedia.org/wikipedia/commons/thumb/9/9a/Fire_engines_in_Kiev%2C_Ukraine.JPG/330px-Fire_engines_in_Kiev%2C_Ukraine.JPG 1.5x, //web.archive.org/web/20160627225612im_/https://upload.wikimedia.org/wikipedia/commons/thumb/9/9a/Fire_engines_in_Kiev%2C_Ukraine.JPG/440px-Fire_engines_in_Kiev%2C_Ukraine.JPG 2x" data-file-width="3648" data-file-height="2736"/></a> <div class="thumbcaption"> <div class="magnify"><a href="/web/20160627225612/https://en.wikipedia.org/wiki/File:Fire_engines_in_Kiev,_Ukraine.JPG" class="internal" title="Enlarge"></a></div> Gas network emergency vehicle responding to a major fire in <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Kiev" title="Kiev">Kiev</a>, <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Ukraine" title="Ukraine">Ukraine</a></div> </div> </div> Explosions caused by natural <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Gas_leak" title="Gas leak">gas leaks</a> 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. 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, disintegrating one or more buildings in the process. The gas usually dissipates readily outdoors, but can sometimes collect in dangerous quantities if flow rates are high enough. However, considering the tens of millions of structures that use the fuel, the individual risk of using natural gas is very low. <h3>Risk of Carbon Monoxide Inhalation[<a href="/web/20160627225612/https://en.wikipedia.org/w/index.php?title=Natural_gas&action=edit&section=27" title="Edit section: Risk of Carbon Monoxide Inhalation">edit</a>]</h3> Natural gas heating systems may cause <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Carbon_monoxide" title="Carbon monoxide">carbon monoxide</a> poisoning if unvented or poorly vented. In 2011, natural gas furnaces, space heaters, water heaters and stoves were blamed for 11 carbon monoxide deaths in the US. Another 22 deaths were attributed to appliances running on liquified petroleum gas, and 17 deaths on gas of unspecified type. Improvements in natural gas furnace designs have greatly reduced CO poisoning concerns. <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Carbon_monoxide_detector" title="Carbon monoxide detector">Detectors</a> are also available that warn of carbon monoxide and/or explosive gas (methane, propane, etc.).<a href="#cite_note-106">[106]</a> <h2>Energy content, statistics, and pricing[<a href="/web/20160627225612/https://en.wikipedia.org/w/index.php?title=Natural_gas&action=edit&section=28" title="Edit section: Energy content, statistics, and pricing">edit</a>]</h2> <div role="note" class="hatnote relarticle mainarticle">Main article: <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Natural_gas_prices" title="Natural gas prices">Natural gas prices</a></div> <div role="note" class="hatnote">See also: <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Billion_cubic_metres_of_natural_gas" title="Billion cubic metres of natural gas">Billion cubic metres of natural gas</a></div> <div class="thumb tright"> <div class="thumbinner" style="width:302px;"><a href="/web/20160627225612/https://en.wikipedia.org/wiki/File:Henry_hub_NG_prices.svg" class="image"><img alt="" src="//web.archive.org/web/20160627225612im_/https://upload.wikimedia.org/wikipedia/commons/thumb/d/dd/Henry_hub_NG_prices.svg/300px-Henry_hub_NG_prices.svg.png" width="300" height="227" class="thumbimage" srcset="//web.archive.org/web/20160627225612im_/https://upload.wikimedia.org/wikipedia/commons/thumb/d/dd/Henry_hub_NG_prices.svg/450px-Henry_hub_NG_prices.svg.png 1.5x, //web.archive.org/web/20160627225612im_/https://upload.wikimedia.org/wikipedia/commons/thumb/d/dd/Henry_hub_NG_prices.svg/600px-Henry_hub_NG_prices.svg.png 2x" data-file-width="517" data-file-height="391"/></a> <div class="thumbcaption"> <div class="magnify"><a href="/web/20160627225612/https://en.wikipedia.org/wiki/File:Henry_hub_NG_prices.svg" class="internal" title="Enlarge"></a></div> <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Natural_gas_prices" title="Natural gas prices">Natural gas prices</a> at the <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Henry_Hub" title="Henry Hub">Henry Hub</a> in US dollars per million BTUs ($/mmbtu).</div> </div> </div> <div class="thumb tright"> <div class="thumbinner" style="width:222px;"><a href="/web/20160627225612/https://en.wikipedia.org/wiki/File:Natural_Gas_Price_Comparison.png" class="image"><img alt="" src="//web.archive.org/web/20160627225612im_/https://upload.wikimedia.org/wikipedia/commons/thumb/6/6c/Natural_Gas_Price_Comparison.png/220px-Natural_Gas_Price_Comparison.png" width="220" height="131" class="thumbimage" srcset="//web.archive.org/web/20160627225612im_/https://upload.wikimedia.org/wikipedia/commons/thumb/6/6c/Natural_Gas_Price_Comparison.png/330px-Natural_Gas_Price_Comparison.png 1.5x, //web.archive.org/web/20160627225612im_/https://upload.wikimedia.org/wikipedia/commons/thumb/6/6c/Natural_Gas_Price_Comparison.png/440px-Natural_Gas_Price_Comparison.png 2x" data-file-width="566" data-file-height="338"/></a> <div class="thumbcaption"> <div class="magnify"><a href="/web/20160627225612/https://en.wikipedia.org/wiki/File:Natural_Gas_Price_Comparison.png" class="internal" title="Enlarge"></a></div> Comparison of natural gas prices in Japan, United Kingdom, and United States, 2007–2011</div> </div> </div> Quantities of natural gas are measured in <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Normal_cubic_meter" class="mw-redirect" title="Normal cubic meter">normal cubic meters</a> (corresponding to 0 °C at 101.325 <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Atmosphere_(unit)" title="Atmosphere (unit)">kPa</a>) or in <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Standard_cubic_feet" class="mw-redirect" title="Standard cubic feet">standard cubic feet</a> (corresponding to 60 °F (16 °C) and 14.73 <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Pounds_per_square_inch" title="Pounds per square inch">psia</a>). The <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Higher_heating_value" class="mw-redirect" title="Higher heating value">gross heat of combustion</a> of 1 m3 of commercial quality natural gas is around 39 <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Joule" title="Joule">MJ</a> (≈10.8 <a href="/web/20160627225612/https://en.wikipedia.org/wiki/KWh" class="mw-redirect" title="KWh">kWh</a>), but this can vary by several percent. This comes to about 49 <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Joule" title="Joule">MJ</a> (≈13.5 <a href="/web/20160627225612/https://en.wikipedia.org/wiki/KWh" class="mw-redirect" title="KWh">kWh</a>) for 1 kg of natural gas (assuming a density of 0.8 kg m−3, an approximate value).[<a href="/web/20160627225612/https://en.wikipedia.org/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed">citation needed</a>] The price of natural gas varies greatly depending on location and type of consumer. In 2007, a price of $7 per 1000 cubic feet (about 25 cents per m3) was typical in the United States. The typical caloric value of natural gas is roughly 1,000 <a href="/web/20160627225612/https://en.wikipedia.org/wiki/British_thermal_unit" title="British thermal unit">British thermal units</a> (BTU) per cubic foot, depending on gas composition. This corresponds to around $7 per million BTU, or around $7 per <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Gigajoule" class="mw-redirect" title="Gigajoule">gigajoule</a>. In April 2008, the wholesale price was $10 per 1,000 cubic feet (28 m3) ($10/MMBTU).<a href="#cite_note-107">[107]</a> The residential price varies from 50% to 300% more than the wholesale price. At the end of 2007, this was $12–$16 per 1000 cubic feet (about 50 cents per m3).<a href="#cite_note-108">[108]</a> Natural gas in the United States is traded as a <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Futures_contract" title="Futures contract">futures contract</a> on the <a href="/web/20160627225612/https://en.wikipedia.org/wiki/New_York_Mercantile_Exchange" title="New York Mercantile Exchange">New York Mercantile Exchange</a>. Each contract is for 10,000 MMBTU (~10,550 <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Gigajoule" class="mw-redirect" title="Gigajoule">gigajoules</a>), or 10 billion BTU. Thus, if the price of gas is $10 per million BTUs on the NYMEX, the contract is worth $100,000. <h3>European Union[<a href="/web/20160627225612/https://en.wikipedia.org/w/index.php?title=Natural_gas&action=edit&section=29" title="Edit section: European Union">edit</a>]</h3> Gas prices for end users vary greatly across the EU.<a href="#cite_note-109">[109]</a> A single European energy market, one of the key objectives of the European Union, should level the prices of gas in all <a href="/web/20160627225612/https://en.wikipedia.org/wiki/European_Union" title="European Union">EU</a> member states. Moreover, it would help to resolve supply and <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Global_warming" title="Global warming">global warming</a> issues,<a href="#cite_note-110">[110]</a> as well as strengthen relations with other Mediterranean countries and foster investments in the region.<a href="#cite_note-111">[111]</a> <h3>United States[<a href="/web/20160627225612/https://en.wikipedia.org/w/index.php?title=Natural_gas&action=edit&section=30" title="Edit section: United States">edit</a>]</h3> <div class="thumb tright"> <div class="thumbinner" style="width:352px;"><a href="/web/20160627225612/https://en.wikipedia.org/wiki/File:US_Natural_Gas_Production.svg" class="image"><img alt="" src="//web.archive.org/web/20160627225612im_/https://upload.wikimedia.org/wikipedia/commons/thumb/9/9a/US_Natural_Gas_Production.svg/350px-US_Natural_Gas_Production.svg.png" width="350" height="229" class="thumbimage" srcset="//web.archive.org/web/20160627225612im_/https://upload.wikimedia.org/wikipedia/commons/thumb/9/9a/US_Natural_Gas_Production.svg/525px-US_Natural_Gas_Production.svg.png 1.5x, //web.archive.org/web/20160627225612im_/https://upload.wikimedia.org/wikipedia/commons/thumb/9/9a/US_Natural_Gas_Production.svg/700px-US_Natural_Gas_Production.svg.png 2x" data-file-width="750" data-file-height="490"/></a> <div class="thumbcaption"> <div class="magnify"><a href="/web/20160627225612/https://en.wikipedia.org/wiki/File:US_Natural_Gas_Production.svg" class="internal" title="Enlarge"></a></div> U.S. Natural Gas Marketed Production 1900 to 2012, source US EIA</div> </div> </div> In <a href="/web/20160627225612/https://en.wikipedia.org/wiki/United_States_customary_units" title="United States customary units">US units</a>, one <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Standard_cubic_foot" title="Standard cubic foot">standard cubic foot</a> 1 cubic foot (28 L) of natural gas produces around 1,028 <a href="/web/20160627225612/https://en.wikipedia.org/wiki/British_thermal_unit" title="British thermal unit">British thermal units</a> (1,085 kJ). The actual heating value when the water formed does not condense is the <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Lower_heating_value" class="mw-redirect" title="Lower heating value">net heat of combustion</a> and can be as much as 10% less.<a href="#cite_note-112">[112]</a> In the United States, retail sales are often in units of <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Therm" title="Therm">therms</a> (th); 1 therm = 100,000 BTU. <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Gas_meter" title="Gas meter">Gas meters</a> 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. Wholesale transactions are generally done in <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Decatherm" class="mw-redirect" title="Decatherm">decatherms</a> (Dth), or in thousand decatherms (MDth), or in million decatherms (MMDth). A million decatherms is roughly a billion cubic feet of natural gas. Gas sales to domestic consumers may be in units of 100 standard cubic feet (<a href="/web/20160627225612/https://en.wikipedia.org/wiki/Standard_cubic_foot" title="Standard cubic foot">scf</a>). The typical annual consumption of a single family residence is 1,000 therms or one <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Residential_Customer_Equivalent" title="Residential Customer Equivalent">RCE</a>. <h3>Canada[<a href="/web/20160627225612/https://en.wikipedia.org/w/index.php?title=Natural_gas&action=edit&section=31" title="Edit section: Canada">edit</a>]</h3> Canada uses <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Metric_units" class="mw-redirect" title="Metric units">metric</a> measure for internal trade of petrochemical products. Consequently, natural gas is sold by the <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Gigajoule" class="mw-redirect" title="Gigajoule">Gigajoule</a>, cubic metre (m3) or thousand cubic metres (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, gas is sold by the energy content (GJ). In these areas, almost all meters for residential and small commercial customers measure volume (m3 or ft3), and billing statements include a multiplier to convert the volume to energy content of the local gas supply. A gigajoule (GJ) is a measure approximately equal to half a barrel (250 lbs) of oil, or 1 million BTUs, or 1000 cu ft of gas, or 28 m3 of gas. The energy content of gas supply in Canada can vary from 37 to 43 MJ per m3 depending on gas supply and processing between the wellhead and the customer. <h3>Elsewhere[<a href="/web/20160627225612/https://en.wikipedia.org/w/index.php?title=Natural_gas&action=edit&section=32" title="Edit section: Elsewhere">edit</a>]</h3> In the rest of the world, natural gas is sold in <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Gigajoule" class="mw-redirect" title="Gigajoule">Gigajoule</a> retail units. LNG (<a href="/web/20160627225612/https://en.wikipedia.org/wiki/Liquefied_natural_gas" title="Liquefied natural gas">liquefied natural gas</a>) and LPG (<a href="/web/20160627225612/https://en.wikipedia.org/wiki/Liquefied_petroleum_gas" title="Liquefied petroleum gas">liquefied petroleum gas</a>) are traded in metric tons or MMBTU as spot deliveries. Long term natural gas distribution contracts are signed in cubic metres, and LNG contracts are in metric tonnes (1,000 kg). The LNG and LPG is transported by specialized <a href="/web/20160627225612/https://en.wikipedia.org/wiki/LNG_carrier" title="LNG carrier">transport ships</a>, as the gas is liquified at <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Cryogenic" class="mw-redirect" title="Cryogenic">cryogenic</a> 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. In the Russian Federation, <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Gazprom" title="Gazprom">Gazprom</a> sold approximately 250 billion cubic metres of natural gas in 2008. In 2013 the Group produced 487.4 billion cubic meters of natural and associated gas. Gazprom supplied Europe with 161.5 billion cubic meters of gas in 2013. 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 "supergiant" gas field in the Mediterranean Sea covering about 40 square miles. It was also reported that the gas field could hold a potential 30 trillion cubic feet of natural gas. ENI said that it is about the energy equivalent of 5.5 billion barrels of oil. The 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.<a href="#cite_note-113">[113]</a> <h2>Natural gas as an asset class for institutional investors[<a href="/web/20160627225612/https://en.wikipedia.org/w/index.php?title=Natural_gas&action=edit&section=33" title="Edit section: Natural gas as an asset class for institutional investors">edit</a>]</h2> Research conducted by the <a href="//web.archive.org/web/20160627225612/https://fr.wikipedia.org/wiki/Forum_Mondial_des_Fonds_de_Pension" class="extiw" title="fr:Forum Mondial des Fonds de Pension">World Pensions Council (WPC)</a>[<a href="/web/20160627225612/https://en.wikipedia.org/wiki/Wikipedia:Manual_of_Style/Dates_and_numbers#Chronological_items" title="Wikipedia:Manual of Style/Dates and numbers">when?</a>] suggests that large US and Canadian pension funds and Asian and <a href="/web/20160627225612/https://en.wikipedia.org/wiki/MENA" title="MENA">MENA</a> area <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Sovereign_wealth_fund" title="Sovereign wealth fund">SWF</a> investors have become particularly active in the fields of natural gas and natural gas infrastructure, a trend started in 2005 by the formation of <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Scotia_Gas_Networks" class="mw-redirect" title="Scotia Gas Networks">Scotia Gas Networks</a> in the UK by <a href="/web/20160627225612/https://en.wikipedia.org/wiki/OMERS" title="OMERS">OMERS</a> and <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Ontario_Teachers%27_Pension_Plan" title="Ontario Teachers' Pension Plan">Ontario Teachers' Pension Plan</a>.[<a href="/web/20160627225612/https://en.wikipedia.org/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed">citation needed</a>] <h2>Adsorbed natural gas (ANG)[<a href="/web/20160627225612/https://en.wikipedia.org/w/index.php?title=Natural_gas&action=edit&section=34" title="Edit section: Adsorbed natural gas (ANG)">edit</a>]</h2> Another way to store natural gas is adsorbing it to the porous solids called sorbents. The best condition for methane storage is at room temperature and atmospheric pressure. The used pressure can be up to 4 MPa (about 40 times atmospheric pressure) for having more storage capacity. The most common sorbent used for ANG is activated carbon (AC). Three main types of activated carbons for ANG are: Activated Carbon Fiber (ACF), Powdered Activated Carbon (PAC), activated carbon monolith.<a href="#cite_note-114">[114]</a> <h2>See also[<a href="/web/20160627225612/https://en.wikipedia.org/w/index.php?title=Natural_gas&action=edit&section=35" title="Edit section: See also">edit</a>]</h2> <div class="noprint portal tright" style="border:solid #aaa 1px;margin:0.5em 0 0.5em 1em"> <table style="background:#f9f9f9;font-size:85%;line-height:110%;max-width:175px"> <tr style="vertical-align:middle"> <td style="text-align:center"><a href="/web/20160627225612/https://en.wikipedia.org/wiki/File:Sustainable_development.svg" class="image"><img alt="Portal icon" src="//web.archive.org/web/20160627225612im_/https://upload.wikimedia.org/wikipedia/commons/thumb/7/70/Sustainable_development.svg/32px-Sustainable_development.svg.png" width="32" height="20" class="noviewer" srcset="//web.archive.org/web/20160627225612im_/https://upload.wikimedia.org/wikipedia/commons/thumb/7/70/Sustainable_development.svg/48px-Sustainable_development.svg.png 1.5x, //web.archive.org/web/20160627225612im_/https://upload.wikimedia.org/wikipedia/commons/thumb/7/70/Sustainable_development.svg/64px-Sustainable_development.svg.png 2x" data-file-width="800" data-file-height="510"/></a></td> <td style="padding:0 0.2em;vertical-align:middle;font-style:italic;font-weight:bold"><a href="/web/20160627225612/https://en.wikipedia.org/wiki/Portal:Sustainable_development" title="Portal:Sustainable development">Sustainable development portal</a></td> </tr> <tr style="vertical-align:middle"> <td style="text-align:center"><a href="/web/20160627225612/https://en.wikipedia.org/wiki/File:Crystal_energy.svg" class="image"><img alt="Portal icon" src="//web.archive.org/web/20160627225612im_/https://upload.wikimedia.org/wikipedia/commons/thumb/1/14/Crystal_energy.svg/29px-Crystal_energy.svg.png" width="29" height="28" class="noviewer" srcset="//web.archive.org/web/20160627225612im_/https://upload.wikimedia.org/wikipedia/commons/thumb/1/14/Crystal_energy.svg/44px-Crystal_energy.svg.png 1.5x, //web.archive.org/web/20160627225612im_/https://upload.wikimedia.org/wikipedia/commons/thumb/1/14/Crystal_energy.svg/59px-Crystal_energy.svg.png 2x" data-file-width="130" data-file-height="124"/></a></td> <td style="padding:0 0.2em;vertical-align:middle;font-style:italic;font-weight:bold"><a href="/web/20160627225612/https://en.wikipedia.org/wiki/Portal:Energy" title="Portal:Energy">Energy portal</a></td> </tr> <tr style="vertical-align:middle"> <td style="text-align:center"><a href="/web/20160627225612/https://en.wikipedia.org/wiki/File:Wind-turbine-icon.svg" class="image"><img alt="Portal icon" src="//web.archive.org/web/20160627225612im_/https://upload.wikimedia.org/wikipedia/commons/thumb/a/ad/Wind-turbine-icon.svg/28px-Wind-turbine-icon.svg.png" width="28" height="28" class="noviewer" srcset="//web.archive.org/web/20160627225612im_/https://upload.wikimedia.org/wikipedia/commons/thumb/a/ad/Wind-turbine-icon.svg/42px-Wind-turbine-icon.svg.png 1.5x, //web.archive.org/web/20160627225612im_/https://upload.wikimedia.org/wikipedia/commons/thumb/a/ad/Wind-turbine-icon.svg/56px-Wind-turbine-icon.svg.png 2x" data-file-width="128" data-file-height="128"/></a></td> <td style="padding:0 0.2em;vertical-align:middle;font-style:italic;font-weight:bold"><a href="/web/20160627225612/https://en.wikipedia.org/wiki/Portal:Renewable_energy" title="Portal:Renewable energy">Renewable energy portal</a></td> </tr> </table> </div> <ul> <li><a href="/web/20160627225612/https://en.wikipedia.org/wiki/Associated_petroleum_gas" title="Associated petroleum gas">Associated petroleum gas</a></li> <li><a href="/web/20160627225612/https://en.wikipedia.org/wiki/Compressed_natural_gas" title="Compressed natural gas">Compressed natural gas</a></li> <li><a href="/web/20160627225612/https://en.wikipedia.org/wiki/Drip_gas" class="mw-redirect" title="Drip gas">Drip gas</a></li> <li><a href="/web/20160627225612/https://en.wikipedia.org/wiki/Gas_depletion" title="Gas depletion">Gas depletion</a></li> <li><a href="/web/20160627225612/https://en.wikipedia.org/wiki/Gas_oil_ratio" title="Gas oil ratio">Gas oil ratio</a></li> <li><a href="/web/20160627225612/https://en.wikipedia.org/wiki/Gas_to_liquids" title="Gas to liquids">Gas to liquids</a></li> <li><a href="/web/20160627225612/https://en.wikipedia.org/wiki/Giant_oil_and_gas_fields" title="Giant oil and gas fields">Giant oil and gas fields</a></li> <li><a href="/web/20160627225612/https://en.wikipedia.org/wiki/Shale_gas" title="Shale gas">Shale gas</a></li> <li><a href="/web/20160627225612/https://en.wikipedia.org/wiki/Hydraulic_fracturing" title="Hydraulic fracturing">Hydraulic fracturing</a></li> <li><a href="/web/20160627225612/https://en.wikipedia.org/wiki/Natural_gas_by_country" title="Natural gas by country">Natural gas by country</a></li> <li><a href="/web/20160627225612/https://en.wikipedia.org/wiki/Natural_gas_prices" title="Natural gas prices">Natural gas prices</a></li> <li><a href="/web/20160627225612/https://en.wikipedia.org/wiki/Peak_gas" title="Peak gas">Peak gas</a></li> <li><a href="/web/20160627225612/https://en.wikipedia.org/wiki/Power_to_gas" title="Power to gas">Power to gas</a></li> <li><a href="/web/20160627225612/https://en.wikipedia.org/wiki/Renewable_natural_gas" title="Renewable natural gas">Renewable natural gas</a></li> </ul> General: <ul> <li><a href="/web/20160627225612/https://en.wikipedia.org/wiki/World_energy_resources_and_consumption" class="mw-redirect" title="World energy resources and consumption">World energy resources and consumption</a></li> </ul> <h2>References[<a href="/web/20160627225612/https://en.wikipedia.org/w/index.php?title=Natural_gas&action=edit&section=36" title="Edit section: References">edit</a>]</h2> <div 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This is a paper presented at the Colloquium on Environmental Scholarship 2013 hosted by Vermont Law School (11 October 2013)</li> <li><a rel="nofollow" class="external text" href="https://web.archive.org/web/20160627225612/http://rto.american-environmental.us/BTU_Reduction_and_Gas_Conditioning_System.html">New Technology For High BTU Natural Gas Fuel Conditioning</a></li> <li>GA Mansoori, N Enayati, LB Agyarko (2016), <a rel="nofollow" class="external text" href="https://web.archive.org/web/20160627225612/http://www.worldscientific.com/worldscibooks/10.1142/9699">Energy: Sources, Utilization, Legislation, Sustainability, Illinois as Model State</a>, World Sci. Pub. Co., <a href="/web/20160627225612/https://en.wikipedia.org/wiki/Special:BookSources/9789814704007" class="internal mw-magiclink-isbn">ISBN 978-981-4704-00-7</a></li> </ul> <table class="navbox" style="border-spacing:0"> <tr> <td style="padding:2px"> <table class="nowraplinks collapsible autocollapse navbox-inner" style="border-spacing:0;background:transparent;color:inherit"> <tr> <th scope="col" class="navbox-title" colspan="3"> <div class="plainlinks hlist navbar mini"> <ul> <li class="nv-view"><a href="/web/20160627225612/https://en.wikipedia.org/wiki/Template:Fuel_gas" title="Template:Fuel gas"><abbr title="View this template" style=";;background:none transparent;border:none;">v</abbr></a></li> <li class="nv-talk"><a href="/web/20160627225612/https://en.wikipedia.org/wiki/Template_talk:Fuel_gas" title="Template talk:Fuel gas"><abbr title="Discuss this template" style=";;background:none transparent;border:none;">t</abbr></a></li> <li class="nv-edit"><a class="external text" 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gas">History</a>)</div> </th> <td class="navbox-list navbox-odd" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px"> <div style="padding:0em 0.25em"> <ul> <li><a href="/web/20160627225612/https://en.wikipedia.org/wiki/Coal_gas" title="Coal gas">Coal gas</a> <ul> <li><a href="/web/20160627225612/https://en.wikipedia.org/wiki/Coal_gasification" title="Coal gasification">Coal gasification</a></li> <li><a href="/web/20160627225612/https://en.wikipedia.org/wiki/Underground_coal_gasification" title="Underground coal gasification">Underground coal gasification</a></li> </ul> </li> <li><a href="/web/20160627225612/https://en.wikipedia.org/wiki/Biogas" title="Biogas">Biogas</a></li> <li><a href="/web/20160627225612/https://en.wikipedia.org/wiki/Blast_furnace_gas" title="Blast furnace gas">Blast furnace gas</a></li> <li><a href="/web/20160627225612/https://en.wikipedia.org/wiki/Blau_gas" title="Blau gas">Blau gas</a></li> <li><a href="/web/20160627225612/https://en.wikipedia.org/wiki/Gasification" title="Gasification">Gasification</a></li> <li><a href="/web/20160627225612/https://en.wikipedia.org/wiki/Landfill_gas" title="Landfill gas">Landfill gas</a></li> <li><a href="/web/20160627225612/https://en.wikipedia.org/wiki/Mond_gas" title="Mond gas">Mond gas</a></li> <li><a href="/web/20160627225612/https://en.wikipedia.org/wiki/Pintsch_gas" class="mw-redirect" title="Pintsch gas">Pintsch gas</a></li> <li><a href="/web/20160627225612/https://en.wikipedia.org/wiki/Producer_gas" title="Producer gas">Producer gas</a></li> <li><a href="/web/20160627225612/https://en.wikipedia.org/wiki/Regasification" title="Regasification">Regasification</a></li> <li><a href="/web/20160627225612/https://en.wikipedia.org/wiki/Syngas" title="Syngas">Syngas</a></li> <li><a href="/web/20160627225612/https://en.wikipedia.org/wiki/Water_gas" title="Water gas">Water gas</a></li> <li><a href="/web/20160627225612/https://en.wikipedia.org/wiki/Wood_gas" title="Wood gas">Wood gas</a></li> </ul> </div> </td> </tr> <tr style="height:2px"> <td colspan="2"></td> </tr> <tr> <th scope="row" class="navbox-group" style="padding-left:0;padding-right:0;"> <div style="padding:0em 0.75em;">Natural gas</div> </th> <td class="navbox-list navbox-even" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px"> <div style="padding:0em 0.25em"> <ul> <li><a href="/web/20160627225612/https://en.wikipedia.org/wiki/Associated_petroleum_gas" title="Associated petroleum gas">APG</a></li> <li><a href="/web/20160627225612/https://en.wikipedia.org/wiki/Coalbed_methane" title="Coalbed methane">CBM</a></li> <li><a href="/web/20160627225612/https://en.wikipedia.org/wiki/Compressed_natural_gas" title="Compressed natural gas">CNG</a></li> <li><a href="/web/20160627225612/https://en.wikipedia.org/wiki/HCNG" title="HCNG">HCNG</a></li> <li><a href="/web/20160627225612/https://en.wikipedia.org/wiki/Liquefied_natural_gas" title="Liquefied natural gas">LNG</a></li> <li><a href="/web/20160627225612/https://en.wikipedia.org/wiki/Natural-gas_condensate" title="Natural-gas condensate">NGC</a></li> <li><a href="/web/20160627225612/https://en.wikipedia.org/wiki/Substitute_natural_gas" title="Substitute natural gas">SNG</a> <ul> <li><a href="/web/20160627225612/https://en.wikipedia.org/wiki/Renewable_natural_gas" title="Renewable natural gas">Bio-SNG</a></li> </ul> </li> </ul> </div> </td> </tr> <tr style="height:2px"> <td colspan="2"></td> </tr> <tr> <th scope="row" class="navbox-group" style="padding-left:0;padding-right:0;"> <div style="padding:0em 0.75em;"><a href="/web/20160627225612/https://en.wikipedia.org/wiki/Liquefied_petroleum_gas" title="Liquefied petroleum gas">LPG</a></div> </th> <td class="navbox-list navbox-odd" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px"> <div style="padding:0em 0.25em"> <ul> <li><a href="/web/20160627225612/https://en.wikipedia.org/wiki/Autogas" title="Autogas">Autogas</a></li> <li><a href="/web/20160627225612/https://en.wikipedia.org/wiki/Butane" title="Butane">Butane</a></li> <li><a href="/web/20160627225612/https://en.wikipedia.org/wiki/Propane" title="Propane">Propane</a></li> </ul> </div> </td> </tr> </table> </td> <td class="navbox-image" rowspan="5" style="width:0%;padding:0px 0px 0px 2px"> <div><a href="/web/20160627225612/https://en.wikipedia.org/wiki/File:Gas_flame.jpg" class="image" title="Gas flame"><img alt="Gas flame" src="//web.archive.org/web/20160627225612im_/https://upload.wikimedia.org/wikipedia/commons/thumb/1/11/Gas_flame.jpg/90px-Gas_flame.jpg" width="90" height="81" srcset="//web.archive.org/web/20160627225612im_/https://upload.wikimedia.org/wikipedia/commons/thumb/1/11/Gas_flame.jpg/135px-Gas_flame.jpg 1.5x, //web.archive.org/web/20160627225612im_/https://upload.wikimedia.org/wikipedia/commons/thumb/1/11/Gas_flame.jpg/180px-Gas_flame.jpg 2x" data-file-width="1320" data-file-height="1182"/></a></div> </td> </tr> <tr style="height:2px"> <td colspan="2"></td> </tr> <tr> <th scope="row" class="navbox-group">Infrastructure</th> <td class="navbox-list navbox-even hlist" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px"> <div style="padding:0em 0.25em"> <ul> <li><a href="/web/20160627225612/https://en.wikipedia.org/wiki/Compressor_station" title="Compressor station">Compressor station</a></li> <li><a href="/web/20160627225612/https://en.wikipedia.org/wiki/Gas_carrier" title="Gas carrier">Gas carrier</a></li> <li><a href="/web/20160627225612/https://en.wikipedia.org/wiki/Gas_holder" title="Gas holder">Gas holder</a></li> <li><a href="/web/20160627225612/https://en.wikipedia.org/wiki/Gas_meter" title="Gas meter">Gas meter</a></li> <li><a href="/web/20160627225612/https://en.wikipedia.org/wiki/Gasworks" title="Gasworks">Gasworks</a></li> <li><a href="/web/20160627225612/https://en.wikipedia.org/wiki/Natural-gas_processing" title="Natural-gas processing">Natural-gas processing</a></li> <li><a href="/web/20160627225612/https://en.wikipedia.org/wiki/Natural_gas_storage" title="Natural gas storage">Natural gas storage</a></li> <li><a href="/web/20160627225612/https://en.wikipedia.org/wiki/Odorizer" title="Odorizer">Odorizer</a></li> <li><a href="/web/20160627225612/https://en.wikipedia.org/wiki/Pipeline_transport" title="Pipeline transport">Pipeline transport</a></li> </ul> </div> </td> </tr> <tr style="height:2px"> <td colspan="2"></td> </tr> <tr> <th scope="row" class="navbox-group">Uses</th> <td class="navbox-list navbox-odd hlist" style="text-align:left;border-left-width:2px;border-left-style:solid;width:100%;padding:0px"> <div style="padding:0em 0.25em"> <ul> <li><a 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class="wb-otherproject-link wb-otherproject-commons"><a href="https://web.archive.org/web/20160627225612/https://commons.wikimedia.org/wiki/Category:Natural_gas" hreflang="en">Wikimedia Commons</a></li> </ul> </div> </div> <div class="portal" role="navigation" id="p-lang" aria-labelledby="p-lang-label"> <h3 id="p-lang-label">Languages</h3> <div class="body"> <ul> <li class="interlanguage-link interwiki-af"><a href="//web.archive.org/web/20160627225612/https://af.wikipedia.org/wiki/Aardgas" title="Aardgas – Afrikaans" lang="af" hreflang="af">Afrikaans</a></li><li class="interlanguage-link interwiki-ar"><a href="//web.archive.org/web/20160627225612/https://ar.wikipedia.org/wiki/%D8%BA%D8%A7%D8%B2_%D8%B7%D8%A8%D9%8A%D8%B9%D9%8A" title="غاز طبيعي – Arabic" lang="ar" hreflang="ar">العربية</a></li><li class="interlanguage-link interwiki-an"><a href="//web.archive.org/web/20160627225612/https://an.wikipedia.org/wiki/Gas_natural" title="Gas natural – Aragonese" lang="an" hreflang="an">Aragonés</a></li><li class="interlanguage-link interwiki-ast"><a href="//web.archive.org/web/20160627225612/https://ast.wikipedia.org/wiki/Gas_natural" title="Gas natural – Asturian" lang="ast" hreflang="ast">Asturianu</a></li><li class="interlanguage-link interwiki-az"><a href="//web.archive.org/web/20160627225612/https://az.wikipedia.org/wiki/T%C9%99bii_qaz" title="Təbii qaz – Azerbaijani" lang="az" hreflang="az">Azərbaycanca</a></li><li class="interlanguage-link interwiki-bn"><a href="//web.archive.org/web/20160627225612/https://bn.wikipedia.org/wiki/%E0%A6%AA%E0%A7%8D%E0%A6%B0%E0%A6%BE%E0%A6%95%E0%A7%83%E0%A6%A4%E0%A6%BF%E0%A6%95_%E0%A6%97%E0%A7%8D%E0%A6%AF%E0%A6%BE%E0%A6%B8" title="প্রাকৃতিক গ্যাস – Bengali" lang="bn" hreflang="bn">বাংলা</a></li><li class="interlanguage-link interwiki-zh-min-nan"><a href="//web.archive.org/web/20160627225612/https://zh-min-nan.wikipedia.org/wiki/Thian-ji%C3%A2n-kh%C3%AC" title="Thian-jiân-khì – Chinese (Min Nan)" lang="zh-min-nan" hreflang="zh-min-nan">Bân-lâm-gú</a></li><li class="interlanguage-link interwiki-be"><a href="//web.archive.org/web/20160627225612/https://be.wikipedia.org/wiki/%D0%9F%D1%80%D1%8B%D1%80%D0%BE%D0%B4%D0%BD%D1%8B_%D0%B3%D0%B0%D0%B7" title="Прыродны газ – Belarusian" lang="be" hreflang="be">Беларуская</a></li><li class="interlanguage-link interwiki-be-x-old"><a href="//web.archive.org/web/20160627225612/https://be-x-old.wikipedia.org/wiki/%D0%9F%D1%80%D1%8B%D1%80%D0%BE%D0%B4%D0%BD%D1%8B_%D0%B3%D0%B0%D0%B7" title="Прыродны газ – беларуская (тарашкевіца)‎" lang="be-x-old" hreflang="be-x-old">Беларуская (тарашкевіца)‎</a></li><li class="interlanguage-link interwiki-bg"><a href="//web.archive.org/web/20160627225612/https://bg.wikipedia.org/wiki/%D0%9F%D1%80%D0%B8%D1%80%D0%BE%D0%B4%D0%B5%D0%BD_%D0%B3%D0%B0%D0%B7" title="Природен газ – Bulgarian" lang="bg" hreflang="bg">Български</a></li><li class="interlanguage-link interwiki-bs"><a href="//web.archive.org/web/20160627225612/https://bs.wikipedia.org/wiki/Zemni_plin" title="Zemni plin – Bosnian" lang="bs" hreflang="bs">Bosanski</a></li><li class="interlanguage-link interwiki-ca"><a href="//web.archive.org/web/20160627225612/https://ca.wikipedia.org/wiki/Gas_natural" title="Gas natural – Catalan" lang="ca" hreflang="ca">Català</a></li><li class="interlanguage-link interwiki-cs"><a href="//web.archive.org/web/20160627225612/https://cs.wikipedia.org/wiki/Zemn%C3%AD_plyn" title="Zemní plyn – Czech" lang="cs" hreflang="cs">Čeština</a></li><li class="interlanguage-link interwiki-cy"><a href="//web.archive.org/web/20160627225612/https://cy.wikipedia.org/wiki/Nwy_naturiol" title="Nwy naturiol – Welsh" lang="cy" hreflang="cy">Cymraeg</a></li><li class="interlanguage-link interwiki-da"><a href="//web.archive.org/web/20160627225612/https://da.wikipedia.org/wiki/Naturgas" title="Naturgas – Danish" lang="da" hreflang="da">Dansk</a></li><li class="interlanguage-link interwiki-de"><a href="//web.archive.org/web/20160627225612/https://de.wikipedia.org/wiki/Erdgas" title="Erdgas – German" lang="de" hreflang="de">Deutsch</a></li><li class="interlanguage-link interwiki-et"><a href="//web.archive.org/web/20160627225612/https://et.wikipedia.org/wiki/Maagaas" title="Maagaas – Estonian" lang="et" hreflang="et">Eesti</a></li><li class="interlanguage-link interwiki-el"><a href="//web.archive.org/web/20160627225612/https://el.wikipedia.org/wiki/%CE%A6%CF%85%CF%83%CE%B9%CE%BA%CF%8C_%CE%B1%CE%AD%CF%81%CE%B9%CE%BF" title="Φυσικό αέριο – Greek" lang="el" hreflang="el">Ελληνικά</a></li><li class="interlanguage-link interwiki-es"><a href="//web.archive.org/web/20160627225612/https://es.wikipedia.org/wiki/Gas_natural" title="Gas natural – Spanish" lang="es" hreflang="es">Español</a></li><li class="interlanguage-link interwiki-eo"><a href="//web.archive.org/web/20160627225612/https://eo.wikipedia.org/wiki/Tergaso" title="Tergaso – Esperanto" lang="eo" hreflang="eo">Esperanto</a></li><li class="interlanguage-link interwiki-eu"><a href="//web.archive.org/web/20160627225612/https://eu.wikipedia.org/wiki/Gas_natural" title="Gas natural – Basque" lang="eu" hreflang="eu">Euskara</a></li><li class="interlanguage-link interwiki-fa"><a href="//web.archive.org/web/20160627225612/https://fa.wikipedia.org/wiki/%DA%AF%D8%A7%D8%B2_%D8%B7%D8%A8%DB%8C%D8%B9%DB%8C" title="گاز طبیعی – Persian" lang="fa" hreflang="fa">فارسی</a></li><li class="interlanguage-link interwiki-fr"><a href="//web.archive.org/web/20160627225612/https://fr.wikipedia.org/wiki/Gaz_naturel" title="Gaz naturel – French" lang="fr" hreflang="fr">Français</a></li><li class="interlanguage-link interwiki-fy"><a href="//web.archive.org/web/20160627225612/https://fy.wikipedia.org/wiki/Ierdgas" title="Ierdgas – Western Frisian" lang="fy" hreflang="fy">Frysk</a></li><li class="interlanguage-link interwiki-ga"><a href="//web.archive.org/web/20160627225612/https://ga.wikipedia.org/wiki/G%C3%A1s_n%C3%A1d%C3%BArtha" title="Gás nádúrtha – Irish" lang="ga" hreflang="ga">Gaeilge</a></li><li class="interlanguage-link interwiki-gl"><a href="//web.archive.org/web/20160627225612/https://gl.wikipedia.org/wiki/Gas_natural" title="Gas natural – Galician" lang="gl" hreflang="gl">Galego</a></li><li class="interlanguage-link interwiki-ko"><a href="//web.archive.org/web/20160627225612/https://ko.wikipedia.org/wiki/%EC%B2%9C%EC%97%B0_%EA%B0%80%EC%8A%A4" title="천연 가스 – Korean" lang="ko" hreflang="ko">한국어</a></li><li class="interlanguage-link interwiki-hy"><a href="//web.archive.org/web/20160627225612/https://hy.wikipedia.org/wiki/%D4%B2%D5%B6%D5%A1%D5%AF%D5%A1%D5%B6_%D5%A3%D5%A1%D5%A6" title="Բնական գազ – Armenian" lang="hy" hreflang="hy">Հայերեն</a></li><li class="interlanguage-link interwiki-hi"><a href="//web.archive.org/web/20160627225612/https://hi.wikipedia.org/wiki/%E0%A4%AA%E0%A5%8D%E0%A4%B0%E0%A4%BE%E0%A4%95%E0%A5%83%E0%A4%A4%E0%A4%BF%E0%A4%95_%E0%A4%97%E0%A5%88%E0%A4%B8" title="प्राकृतिक गैस – Hindi" lang="hi" hreflang="hi">हिन्दी</a></li><li class="interlanguage-link interwiki-hr"><a href="//web.archive.org/web/20160627225612/https://hr.wikipedia.org/wiki/Prirodni_plin" title="Prirodni plin – Croatian" lang="hr" hreflang="hr">Hrvatski</a></li><li class="interlanguage-link interwiki-io"><a href="//web.archive.org/web/20160627225612/https://io.wikipedia.org/wiki/Naturala_gaso" title="Naturala gaso – Ido" lang="io" hreflang="io">Ido</a></li><li class="interlanguage-link interwiki-id"><a href="//web.archive.org/web/20160627225612/https://id.wikipedia.org/wiki/Gas_alam" title="Gas alam – Indonesian" lang="id" hreflang="id">Bahasa Indonesia</a></li><li class="interlanguage-link interwiki-is"><a href="//web.archive.org/web/20160627225612/https://is.wikipedia.org/wiki/Jar%C3%B0gas" title="Jarðgas – Icelandic" lang="is" hreflang="is">Íslenska</a></li><li class="interlanguage-link interwiki-it"><a href="//web.archive.org/web/20160627225612/https://it.wikipedia.org/wiki/Gas_naturale" title="Gas naturale – Italian" lang="it" hreflang="it">Italiano</a></li><li class="interlanguage-link interwiki-he"><a href="//web.archive.org/web/20160627225612/https://he.wikipedia.org/wiki/%D7%92%D7%96_%D7%98%D7%91%D7%A2%D7%99" title="גז טבעי – Hebrew" lang="he" hreflang="he">עברית</a></li><li class="interlanguage-link interwiki-jv"><a href="//web.archive.org/web/20160627225612/https://jv.wikipedia.org/wiki/Gas_bumi" title="Gas bumi – Javanese" lang="jv" hreflang="jv">Basa Jawa</a></li><li class="interlanguage-link interwiki-ka"><a href="//web.archive.org/web/20160627225612/https://ka.wikipedia.org/wiki/%E1%83%91%E1%83%A3%E1%83%9C%E1%83%94%E1%83%91%E1%83%A0%E1%83%98%E1%83%95%E1%83%98_%E1%83%90%E1%83%98%E1%83%A0%E1%83%98" title="ბუნებრივი აირი – Georgian" lang="ka" hreflang="ka">ქართული</a></li><li class="interlanguage-link interwiki-kk"><a href="//web.archive.org/web/20160627225612/https://kk.wikipedia.org/wiki/%D0%A2%D0%B0%D0%B1%D0%B8%D2%93%D0%B8_%D0%B3%D0%B0%D0%B7" title="Табиғи газ – Kazakh" lang="kk" hreflang="kk">Қазақша</a></li><li class="interlanguage-link interwiki-sw"><a href="//web.archive.org/web/20160627225612/https://sw.wikipedia.org/wiki/Gesi_asilia" title="Gesi asilia – Swahili" lang="sw" hreflang="sw">Kiswahili</a></li><li class="interlanguage-link interwiki-ht"><a href="//web.archive.org/web/20160627225612/https://ht.wikipedia.org/wiki/Gaz_natir%C3%A8l" title="Gaz natirèl – Haitian Creole" lang="ht" hreflang="ht">Kreyòl ayisyen</a></li><li class="interlanguage-link interwiki-ku"><a href="//web.archive.org/web/20160627225612/https://ku.wikipedia.org/wiki/Erdgaz" title="Erdgaz – Kurdish" lang="ku" hreflang="ku">Kurdî</a></li><li class="interlanguage-link interwiki-la"><a href="//web.archive.org/web/20160627225612/https://la.wikipedia.org/wiki/Gasium_naturale" title="Gasium naturale – Latin" lang="la" hreflang="la">Latina</a></li><li class="interlanguage-link interwiki-lv"><a href="//web.archive.org/web/20160627225612/https://lv.wikipedia.org/wiki/Dabasg%C4%81ze" title="Dabasgāze – Latvian" lang="lv" hreflang="lv">Latviešu</a></li><li class="interlanguage-link interwiki-lt"><a href="//web.archive.org/web/20160627225612/https://lt.wikipedia.org/wiki/Gamtin%C4%97s_dujos" title="Gamtinės dujos – Lithuanian" lang="lt" hreflang="lt">Lietuvių</a></li><li class="interlanguage-link interwiki-li"><a href="//web.archive.org/web/20160627225612/https://li.wikipedia.org/wiki/Aerdgaas" title="Aerdgaas – Limburgish" lang="li" hreflang="li">Limburgs</a></li><li class="interlanguage-link interwiki-lmo"><a href="//web.archive.org/web/20160627225612/https://lmo.wikipedia.org/wiki/Gass_nat%C3%BCral" title="Gass natüral – Lombard" lang="lmo" hreflang="lmo">Lumbaart</a></li><li class="interlanguage-link interwiki-hu"><a href="//web.archive.org/web/20160627225612/https://hu.wikipedia.org/wiki/F%C3%B6ldg%C3%A1z" title="Földgáz – Hungarian" lang="hu" hreflang="hu">Magyar</a></li><li class="interlanguage-link interwiki-mk"><a href="//web.archive.org/web/20160627225612/https://mk.wikipedia.org/wiki/%D0%97%D0%B5%D0%BC%D0%B5%D0%BD_%D0%B3%D0%B0%D1%81" title="Земен гас – Macedonian" lang="mk" hreflang="mk">Македонски</a></li><li class="interlanguage-link interwiki-ml"><a href="//web.archive.org/web/20160627225612/https://ml.wikipedia.org/wiki/%E0%B4%AA%E0%B5%8D%E0%B4%B0%E0%B4%95%E0%B5%83%E0%B4%A4%E0%B4%BF%E0%B4%B5%E0%B4%BE%E0%B4%A4%E0%B4%95%E0%B4%82" title="പ്രകൃതിവാതകം – Malayalam" lang="ml" hreflang="ml">മലയാളം</a></li><li class="interlanguage-link interwiki-mr"><a href="//web.archive.org/web/20160627225612/https://mr.wikipedia.org/wiki/%E0%A4%A8%E0%A5%88%E0%A4%B8%E0%A4%B0%E0%A5%8D%E0%A4%97%E0%A4%BF%E0%A4%95_%E0%A4%B5%E0%A4%BE%E0%A4%AF%E0%A5%82" title="नैसर्गिक वायू – Marathi" lang="mr" hreflang="mr">मराठी</a></li><li class="interlanguage-link interwiki-ms"><a href="//web.archive.org/web/20160627225612/https://ms.wikipedia.org/wiki/Gas_asli" title="Gas asli – Malay" lang="ms" hreflang="ms">Bahasa Melayu</a></li><li class="interlanguage-link interwiki-mn"><a href="//web.archive.org/web/20160627225612/https://mn.wikipedia.org/wiki/%D0%91%D0%B0%D0%B9%D0%B3%D0%B0%D0%BB%D0%B8%D0%B9%D0%BD_%D1%85%D0%B8%D0%B9" title="Байгалийн хий – Mongolian" lang="mn" hreflang="mn">Монгол</a></li><li class="interlanguage-link interwiki-my"><a href="//web.archive.org/web/20160627225612/https://my.wikipedia.org/wiki/%E1%80%9E%E1%80%98%E1%80%AC%E1%80%9D%E1%80%93%E1%80%AC%E1%80%90%E1%80%BA%E1%80%84%E1%80%BD%E1%80%B1%E1%80%B7" title="သဘာဝဓာတ်ငွေ့ – Burmese" lang="my" hreflang="my">မြန်မာဘာသာ</a></li><li class="interlanguage-link interwiki-nl"><a href="//web.archive.org/web/20160627225612/https://nl.wikipedia.org/wiki/Aardgas" title="Aardgas – Dutch" lang="nl" hreflang="nl">Nederlands</a></li><li class="interlanguage-link interwiki-nds-nl"><a href="//web.archive.org/web/20160627225612/https://nds-nl.wikipedia.org/wiki/Eerdgas" title="Eerdgas – Low Saxon" lang="nds-NL" hreflang="nds-NL">Nedersaksies</a></li><li class="interlanguage-link interwiki-ja"><a href="//web.archive.org/web/20160627225612/https://ja.wikipedia.org/wiki/%E5%A4%A9%E7%84%B6%E3%82%AC%E3%82%B9" title="天然ガス – Japanese" lang="ja" hreflang="ja">日本語</a></li><li class="interlanguage-link interwiki-no"><a href="//web.archive.org/web/20160627225612/https://no.wikipedia.org/wiki/Naturgass" title="Naturgass – Norwegian" lang="no" hreflang="no">Norsk bokmål</a></li><li class="interlanguage-link interwiki-nn"><a href="//web.archive.org/web/20160627225612/https://nn.wikipedia.org/wiki/Naturgass" title="Naturgass – Norwegian Nynorsk" lang="nn" hreflang="nn">Norsk nynorsk</a></li><li class="interlanguage-link interwiki-oc"><a href="//web.archive.org/web/20160627225612/https://oc.wikipedia.org/wiki/Gas_naturau" title="Gas naturau – Occitan" lang="oc" hreflang="oc">Occitan</a></li><li class="interlanguage-link interwiki-uz"><a href="//web.archive.org/web/20160627225612/https://uz.wikipedia.org/wiki/Tabiiy_gazlar" title="Tabiiy gazlar – Uzbek" lang="uz" hreflang="uz">Oʻzbekcha/ўзбекча</a></li><li class="interlanguage-link interwiki-pa"><a href="//web.archive.org/web/20160627225612/https://pa.wikipedia.org/wiki/%E0%A8%95%E0%A9%81%E0%A8%A6%E0%A8%B0%E0%A8%A4%E0%A9%80_%E0%A8%97%E0%A9%88%E0%A8%B8" title="ਕੁਦਰਤੀ ਗੈਸ – Punjabi" lang="pa" hreflang="pa">ਪੰਜਾਬੀ</a></li><li class="interlanguage-link interwiki-pl"><a href="//web.archive.org/web/20160627225612/https://pl.wikipedia.org/wiki/Gaz_ziemny" title="Gaz ziemny – Polish" lang="pl" hreflang="pl">Polski</a></li><li class="interlanguage-link interwiki-pt"><a href="//web.archive.org/web/20160627225612/https://pt.wikipedia.org/wiki/G%C3%A1s_natural" title="Gás natural – Portuguese" lang="pt" hreflang="pt">Português</a></li><li class="interlanguage-link interwiki-kaa"><a href="//web.archive.org/web/20160627225612/https://kaa.wikipedia.org/wiki/Ta%27biyiy_ga%27z" title="Ta'biyiy ga'z – Kara-Kalpak" lang="kaa" hreflang="kaa">Qaraqalpaqsha</a></li><li class="interlanguage-link interwiki-ro"><a href="//web.archive.org/web/20160627225612/https://ro.wikipedia.org/wiki/Gaz_natural" title="Gaz natural – Romanian" lang="ro" hreflang="ro">Română</a></li><li class="interlanguage-link interwiki-qu"><a href="//web.archive.org/web/20160627225612/https://qu.wikipedia.org/wiki/Allpa_wapsi" title="Allpa wapsi – Quechua" lang="qu" hreflang="qu">Runa Simi</a></li><li class="interlanguage-link interwiki-rue"><a href="//web.archive.org/web/20160627225612/https://rue.wikipedia.org/wiki/%D0%97%D0%B5%D0%BC%D0%BD%D1%8B%D0%B9_%D2%91%D0%B0%D0%B7" title="Земный ґаз – Rusyn" lang="rue" hreflang="rue">Русиньскый</a></li><li class="interlanguage-link interwiki-ru"><a href="//web.archive.org/web/20160627225612/https://ru.wikipedia.org/wiki/%D0%9F%D1%80%D0%B8%D1%80%D0%BE%D0%B4%D0%BD%D1%8B%D0%B9_%D0%B3%D0%B0%D0%B7" title="Природный газ – Russian" lang="ru" hreflang="ru">Русский</a></li><li class="interlanguage-link interwiki-sah"><a href="//web.archive.org/web/20160627225612/https://sah.wikipedia.org/wiki/%D0%90%D0%B9%D1%8B%D0%BB%D2%95%D0%B0_%D0%B3%D0%B0%D0%B0%D2%BB%D0%B0" title="Айылҕа гааһа – Sakha" lang="sah" hreflang="sah">Саха тыла</a></li><li class="interlanguage-link interwiki-sco"><a href="//web.archive.org/web/20160627225612/https://sco.wikipedia.org/wiki/Naitural_gas" title="Naitural gas – Scots" lang="sco" hreflang="sco">Scots</a></li><li class="interlanguage-link interwiki-sq"><a href="//web.archive.org/web/20160627225612/https://sq.wikipedia.org/wiki/Gazi_natyror" title="Gazi natyror – Albanian" lang="sq" hreflang="sq">Shqip</a></li><li class="interlanguage-link interwiki-simple"><a href="//web.archive.org/web/20160627225612/https://simple.wikipedia.org/wiki/Natural_gas" title="Natural gas – Simple English" lang="simple" hreflang="simple">Simple English</a></li><li class="interlanguage-link interwiki-sk"><a href="//web.archive.org/web/20160627225612/https://sk.wikipedia.org/wiki/Zemn%C3%BD_plyn" title="Zemný plyn – Slovak" lang="sk" hreflang="sk">Slovenčina</a></li><li class="interlanguage-link interwiki-sl"><a href="//web.archive.org/web/20160627225612/https://sl.wikipedia.org/wiki/Zemeljski_plin" title="Zemeljski plin – Slovenian" lang="sl" hreflang="sl">Slovenščina</a></li><li class="interlanguage-link interwiki-ckb"><a href="//web.archive.org/web/20160627225612/https://ckb.wikipedia.org/wiki/%DA%AF%D8%A7%D8%B2%DB%8C_%D8%B3%D8%B1%D9%88%D8%B4%D8%AA%DB%8C" title="گازی سروشتی – Central Kurdish" lang="ckb" hreflang="ckb">کوردیی ناوەندی</a></li><li class="interlanguage-link interwiki-sr"><a href="//web.archive.org/web/20160627225612/https://sr.wikipedia.org/wiki/Zemni_gas" title="Zemni gas – Serbian" lang="sr" hreflang="sr">Српски / srpski</a></li><li class="interlanguage-link interwiki-sh"><a href="//web.archive.org/web/20160627225612/https://sh.wikipedia.org/wiki/Zemni_gas" title="Zemni gas – Serbo-Croatian" lang="sh" hreflang="sh">Srpskohrvatski / српскохрватски</a></li><li class="interlanguage-link interwiki-fi"><a href="//web.archive.org/web/20160627225612/https://fi.wikipedia.org/wiki/Maakaasu" title="Maakaasu – Finnish" lang="fi" hreflang="fi">Suomi</a></li><li class="interlanguage-link interwiki-sv"><a href="//web.archive.org/web/20160627225612/https://sv.wikipedia.org/wiki/Naturgas" title="Naturgas – Swedish" lang="sv" hreflang="sv">Svenska</a></li><li class="interlanguage-link interwiki-ta"><a href="//web.archive.org/web/20160627225612/https://ta.wikipedia.org/wiki/%E0%AE%87%E0%AE%AF%E0%AE%B1%E0%AF%8D%E0%AE%95%E0%AF%88_%E0%AE%8E%E0%AE%B0%E0%AE%BF%E0%AE%B5%E0%AE%B3%E0%AE%BF" title="இயற்கை எரிவளி – Tamil" lang="ta" hreflang="ta">தமிழ்</a></li><li class="interlanguage-link interwiki-tt"><a href="//web.archive.org/web/20160627225612/https://tt.wikipedia.org/wiki/Tabi%C4%9Fi_gaz" title="Tabiği gaz – Tatar" lang="tt" hreflang="tt">Татарча/tatarça</a></li><li class="interlanguage-link interwiki-te"><a href="//web.archive.org/web/20160627225612/https://te.wikipedia.org/wiki/%E0%B0%B8%E0%B0%B9%E0%B0%9C_%E0%B0%B5%E0%B0%BE%E0%B0%AF%E0%B1%81%E0%B0%B5%E0%B1%81" title="సహజ వాయువు – Telugu" lang="te" hreflang="te">తెలుగు</a></li><li class="interlanguage-link interwiki-th"><a href="//web.archive.org/web/20160627225612/https://th.wikipedia.org/wiki/%E0%B9%81%E0%B8%81%E0%B9%8A%E0%B8%AA%E0%B8%98%E0%B8%A3%E0%B8%A3%E0%B8%A1%E0%B8%8A%E0%B8%B2%E0%B8%95%E0%B8%B4" title="แก๊สธรรมชาติ – Thai" lang="th" hreflang="th">ไทย</a></li><li class="interlanguage-link interwiki-tg"><a href="//web.archive.org/web/20160627225612/https://tg.wikipedia.org/wiki/%D0%93%D0%B0%D0%B7%D0%B8_%D1%82%D0%B0%D0%B1%D0%B8%D3%A3" title="Гази табиӣ – Tajik" lang="tg" hreflang="tg">Тоҷикӣ</a></li><li class="interlanguage-link interwiki-tr"><a href="//web.archive.org/web/20160627225612/https://tr.wikipedia.org/wiki/Do%C4%9Fal_gaz" title="Doğal gaz – Turkish" lang="tr" hreflang="tr">Türkçe</a></li><li class="interlanguage-link interwiki-uk"><a href="//web.archive.org/web/20160627225612/https://uk.wikipedia.org/wiki/%D0%9F%D1%80%D0%B8%D1%80%D0%BE%D0%B4%D0%BD%D0%B8%D0%B9_%D0%B3%D0%B0%D0%B7" title="Природний газ – Ukrainian" lang="uk" hreflang="uk">Українська</a></li><li class="interlanguage-link interwiki-vep"><a href="//web.archive.org/web/20160627225612/https://vep.wikipedia.org/wiki/Londuseline_gaz" title="Londuseline gaz – Veps" lang="vep" hreflang="vep">Vepsän kel’</a></li><li class="interlanguage-link interwiki-vi"><a href="//web.archive.org/web/20160627225612/https://vi.wikipedia.org/wiki/Kh%C3%AD_thi%C3%AAn_nhi%C3%AAn" title="Khí thiên nhiên – Vietnamese" lang="vi" hreflang="vi">Tiếng Việt</a></li><li class="interlanguage-link interwiki-zh-yue"><a href="//web.archive.org/web/20160627225612/https://zh-yue.wikipedia.org/wiki/%E5%A4%A9%E7%84%B6%E6%B0%A3" title="天然氣 – Cantonese" lang="zh-yue" hreflang="zh-yue">粵語</a></li><li class="interlanguage-link interwiki-zh"><a href="//web.archive.org/web/20160627225612/https://zh.wikipedia.org/wiki/%E5%A4%A9%E7%84%B6%E6%B0%94" title="天然气 – Chinese" lang="zh" hreflang="zh">中文</a></li><li class="uls-p-lang-dummy"><a href="#"></a></li> </ul> <div class="after-portlet after-portlet-lang"><a href="https://web.archive.org/web/20160627225612/https://www.wikidata.org/wiki/Q40858#sitelinks-wikipedia" title="Edit interlanguage links" class="wbc-editpage">Edit links</a></div> </div> </div> </div> </div> <div id="footer" role="contentinfo"> <ul 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