Editing Natural gas (section)

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

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

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


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