Editing Ethanol (section)

=== Energy source ===
{{See also|Food vs. fuel}}
{{Main|Ethanol fuel}}
[[File:Corn vs Ethanol production.webp|thumb|upright=1.36|center|Corn vs ethanol production in the United States
{{legend|#FFD932|Total corn production ([[bushel]]s) (left)}}
{{legend|B51700|Corn used for [[Ethanol fuel]] (bushels) (left)}}
{{legend-line|#313131 solid 3px|Percent of corn used for Ethanol (right)}}
]]

{| class="wikitable" style="float:right; margin-left:1em;"
|+[[Energy density|Energy content]] ([[lower heating value]]) of some fuels compared with ethanol.
|-
!Fuel type|| MJ/L|| MJ/kg|| [[octane rating|Research<br />octane<br />number]]
|-
|[[Wood fuel|Dry wood (20% moisture)]]|| ||~19.5||
|-
|[[Methanol]]||17.9||19.9||108.7<ref name="Fuel 89 (2010) 2713-2720">{{cite journal | doi=10.1016/j.fuel.2010.01.032 | title=Impact of alcohol–gasoline fuel blends on the performance and combustion characteristics of an SI engine | year=2010 | last1=Eyidogan | first1=Muharrem | last2=Ozsezen | first2=Ahmet Necati | last3=Canakci | first3=Mustafa | last4=Turkcan | first4=Ali | name-list-style=vanc | journal=Fuel | volume=89 | issue=10 | pages=2713–2720 | bibcode=2010Fuel...89.2713E}}</ref>
|-
|[[Ethanol fuel|Ethanol]]||21.2<ref name="Thomas">{{cite web | last=Thomas | first=George | url=http://www.eere.energy.gov/hydrogenandfuelcells/pdfs/storage.pdf | title=Overview of Storage Development DOE Hydrogen Program | url-status=dead | archive-url=https://web.archive.org/web/20070221185632/http://www1.eere.energy.gov/hydrogenandfuelcells/pdfs/storage.pdf | archive-date=21 February 2007 | location=Livermore, California | publisher=Sandia National Laboratories | year=2000}}</ref>||26.8<ref name="Thomas" />
||108.6<ref name="Fuel 89 (2010) 2713-2720" />
|-
|[[E85]]<br />(85% ethanol, 15% gasoline)||25.2||33.2||105
|-
|[[Liquefied natural gas]]||25.3||~55||
|-
|[[Autogas]] ([[Liquified petroleum gas|LPG]])<br />(60% [[propane]] + 40% [[butane]])||26.8||50||
|-
|[[Aviation gasoline]]<br />(high-octane gasoline, not jet fuel)||33.5||46.8||100/130 (lean/rich)
|-
|[[Alcohol fuel|Gasohol]]<br />(90% gasoline + 10% ethanol)||33.7||47.1||93/94
|-
| Regular gasoline/petrol||34.8||44.4<ref>{{cite news | url=http://www1.eere.energy.gov/hydrogenandfuelcells/pdfs/storage.pdf | last=Thomas | first=George | name-list-style=vanc | title=Overview of Storage Development DOE Hydrogen Program | publisher=Sandia National Laboratories | year=2000 | access-date=1 August 2009}}</ref>||min. 91
|-
| Premium gasoline/petrol|| || ||max. 104
|-
|[[Diesel fuel|Diesel]]||38.6||45.4||25
|-
|[[Charcoal]], extruded||50||23||
|}

The largest single use of ethanol is as an engine [[fuel]] and [[fuel additive]]. [[Brazil]] in particular relies heavily upon the use of ethanol as an engine fuel, due in part to its role as one of the world's leading producers of ethanol.<ref>{{cite web | title=Availability of Sources of E85 | url=http://www.cleanairtrust.org/Sources-Availability-E85.html | website=Clean Air Trust | access-date=27 July 2015}}</ref><ref>{{cite web | title=Fuel ethanol production worldwide | url=https://www.statista.com/statistics/281606/ethanol-production-in-selected-countries/ | website=Statista | access-date=2 June 2021}}</ref> [[Gasoline]] sold in Brazil contains at least 25% [[anhydrous]] ethanol. Hydrous ethanol (about 95% ethanol and 5% water) can be used as fuel in more than 90% of new gasoline-fueled cars sold in the country.

The US and many other countries primarily use E10 (10% ethanol, sometimes known as gasohol) and E85 (85% ethanol) ethanol/gasoline mixtures. Over time, it is believed that a material portion of the ≈{{convert|150|e9USgal|m3|adj=on}} per year market for gasoline will begin to be replaced with fuel ethanol.<ref name="rfa1">{{cite web | date=20 November 2006 | title=First Commercial U.S. Cellulosic Ethanol Biorefinery Announced | url=http://www.ethanolmarket.com/PressReleaseRFA102006.html | access-date=31 May 2011 | publisher=Renewable Fuels Association}}</ref>

[[File:Ethyl alcohol usp grade.jpg|thumb|upright|[[chemical purity|USP grade]] ethanol for laboratory use]]

Australian law limits the use of pure ethanol from [[sugarcane]] waste to 10% in automobiles. Older cars (and vintage cars designed to use a slower burning fuel) should have the engine valves upgraded or replaced.<ref>{{cite web | url=http://www.mtfca.com.au | title=Model T Ford Club Australia (Inc.) | last=Green | first=Ray | name-list-style=vanc | access-date=24 June 2011 | url-status=dead | archive-url=https://web.archive.org/web/20140114075515/http://mtfca.com.au/ | archive-date=14 January 2014 | df=dmy-all}}</ref>

According to an industry [[advocacy group]], ethanol as a fuel reduces harmful [[tailpipe emissions]] of carbon monoxide, particulate matter, [[oxides of nitrogen]], and other ozone-forming pollutants.<ref>{{cite web | url=http://www.ethanol.org/index.php?id=34&parentid=8#Environment | title=Ethanol 101 | publisher=American Coalition for Ethanol | access-date=26 March 2011 | archive-date=14 November 2020 | archive-url=https://web.archive.org/web/20201114003907/https://ethanol.org/index.php?id=34&parentid=8#Environment | url-status=dead}}</ref> [[Argonne National Laboratory]] analyzed greenhouse gas emissions of many different engine and fuel combinations, and found that [[biodiesel]]/petrodiesel blend ([[B20 (biodiesel)|B20]]) showed a reduction of 8%, conventional [[E85]] ethanol blend a reduction of 17% and [[cellulosic ethanol]] 64%, compared with pure gasoline.<ref>{{cite book | chapter-url=http://www.energyfuturecoalition.org/biofuels/benefits_env_public_health.htm | chapter=The Biofuels FAQs | archive-url=https://web.archive.org/web/20110219052041/http://www.energyfuturecoalition.org/biofuels/benefits_env_public_health.htm | archive-date=19 February 2011 | title=The Biofuels Source Book | author=Energy Future Coalition | publisher=[[United Nations Foundation]]}}</ref> Ethanol has a much greater research octane number (RON) than gasoline, meaning it is less prone to pre-ignition, allowing for better ignition advance which means more torque, and efficiency in addition to the lower carbon emissions.<ref>{{Cite journal | last1=Malaquias | first1=Augusto César Teixeira | last2=Netto | first2=Nilton Antonio Diniz | last3=Filho | first3=Fernando Antonio Rodrigues | last4=da Costa | first4=Roberto Berlini Rodrigues | last5=Langeani | first5=Marcos | last6=Baêta | first6=José Guilherme Coelho | date=2019-11-18 | title=The misleading total replacement of internal combustion engines by electric motors and a study of the Brazilian ethanol importance for the sustainable future of mobility: a review | journal=Journal of the Brazilian Society of Mechanical Sciences and Engineering | language=en | volume=41 | issue=12 | pages=567 | doi=10.1007/s40430-019-2076-1 | issn=1806-3691 | doi-access=free}}</ref>

Ethanol [[combustion]] in an [[internal combustion engine]] yields many of the products of incomplete combustion produced by gasoline and significantly larger amounts of [[formaldehyde]] and related species such as acetaldehyde.<ref>{{cite web | url=https://www.arb.ca.gov/bluebook/bb10/hea/hea-39037_05.htm | author=California Air Resources Board | title=Definition of a Low Emission Motor Vehicle in Compliance with the Mandates of Health and Safety Code Section 39037.05, second release | date=October 1989 | access-date=18 February 2018 | archive-url=https://web.archive.org/web/20180218150535/https://www.arb.ca.gov/bluebook/bb10/hea/hea-39037_05.htm | archive-date=18 February 2018 | url-status=dead}}</ref> This leads to a significantly larger photochemical reactivity and more [[ground level ozone]].<ref>{{cite book | vauthors=Lowi A, Carter WP | date=March 1990 | title=A Method for Evaluating the Atmospheric Ozone Impact of Actual Vehicle emissions | work=S.A.E. Technical Paper | location=Warrendale, Pennsylvania}}</ref> This data has been assembled into The Clean Fuels Report comparison of fuel emissions<ref>{{cite web | vauthors=Jones TT | year=2008 | url=http://www.researchandmarkets.com/reports/598475 | title=The Clean Fuels Report: A Quantitative Comparison Of Motor (engine) Fuels, Related Pollution and Technologies | archive-url=https://archive.today/20120909174028/http://www.researchandmarkets.com/reports/598475 | archive-date=9 September 2012 | url-status=dead | website=researchandmarkets.com}}</ref> and show that ethanol exhaust generates 2.14&nbsp;times as much ozone as gasoline exhaust.<ref>{{cite book | url={{google books | plainurl=y | id=Qg1qDQAAQBAJ | page=60}} | title=Electro-rheological Fluids and Magneto-rheological Suspensions | work=Proceedings of the 12th International Conference | location=Philadelphia | date=16–20 August 2010 | last=Tao | first=Rongjia | name-list-style=vanc | publisher=World Scientific | isbn=9789814340229}}</ref> When this is added into the custom ''Localized Pollution Index'' of The Clean Fuels Report, the local pollution of ethanol (pollution that contributes to smog) is rated 1.7, where gasoline is 1.0 and higher numbers signify greater pollution.<ref>{{Cite news | url=https://www.scientificamerican.com/article/reduce-air-pollution-do-not-rely-on-ethanol/ | title=Want to Reduce Air Pollution? Don't Rely on Ethanol Necessarily | last=Biello | first=David | name-list-style=vanc | work=Scientific American | access-date=11 July 2017 | language=en}}</ref> The [[California Air Resources Board]] formalized this issue in 2008 by recognizing control standards for formaldehydes as an emissions control group, much like the conventional [[NOx]] and reactive organic gases (ROGs).<ref>{{cite web | title=Adoption of the Airborne Toxic Control Measure to Reduce Formaldehyde Emissions from Composite Wood Products | url=http://www.wdma.com/TechnicalCenter/GreenZone/CARB/tabid/111/Default.aspx | archive-url=https://web.archive.org/web/20100309071022/http://www.wdma.com/TechnicalCenter/GreenZone/CARB/tabid/111/Default.aspx | archive-date=9 March 2010 | date=30 July 2008 | location=Chicago & Washington, DC | publisher=Window and Door Manufacturers Association}}</ref>

More than 20% of Brazilian cars are able to use 100% ethanol as fuel, which includes ethanol-only engines and [[flex-fuel]] engines.<ref>{{cite web | url=http://economia.estadao.com.br/noticias/geral,tecnologia-flex-em-automoveis-atrai-estrangeiros,178105 | title=Tecnologia flex atrai estrangeiros | publisher=Agência Estado | language=pt-BR}}</ref> Flex-fuel engines in Brazil are able to work with all ethanol, all gasoline or any mixture of both. In the United States, flex-fuel vehicles can run on 0% to 85% ethanol (15% gasoline) since higher ethanol blends are not yet allowed or efficient. Brazil supports this fleet of ethanol-burning automobiles with large national infrastructure that produces ethanol from domestically grown sugarcane.

Ethanol's high [[miscibility]] with water makes it unsuitable for shipping through modern [[Pipeline transport|pipelines]] like liquid hydrocarbons.<ref name="HornKrupp2009">{{Cite book | first1=Miriam | last1=Horn | first2=Fred | last2=Krupp | name-list-style=vanc | title=Earth: The Sequel: The Race to Reinvent Energy and Stop Global Warming | journal=Physics Today | volume=62 | issue=4 | pages=63–65 | url={{google books | plainurl=y | id=vjs7GtArBNoC | lage=85}} | date=16 March 2009 | isbn=978-0-393-06810-8 | bibcode=2009PhT....62d..63K | doi=10.1063/1.3120901 | s2cid=153892198}}</ref> Mechanics have seen increased cases of damage to small engines (in particular, the [[carburetor]]) and attribute the damage to the increased water retention by ethanol in fuel.<ref><!-- http://www.msnbc.msn.com/id/25936782/ -->[http://www.nbcnews.com/id/25936782/ "Mechanics see ethanol damaging small engines"]{{Webarchive|url=https://web.archive.org/web/20200923224041/http://www.nbcnews.com/id/25936782/ |date=23 September 2020 }}, ''NBC News'', 8 January 2008</ref>

Ethanol was commonly used as fuel in early [[bipropellant]] [[rocket]] (liquid-propelled) vehicles, in conjunction with an [[oxidizer]] such as liquid oxygen. The German A-4 ballistic rocket of [[World War&nbsp;II]] (better known by its propaganda name {{Nowrap|[[V-2]]}}),<ref name="Ignition">{{Cite book | last=Clark | first=John. D. | author-link=John Drury Clark | url=https://archive.org/details/ignitioninformal0000clar | title=Ignition! an informal history of liquid rocket propellants | others=Foreword by Isaac Asimov | date=1972 | publisher=Rutgers University Press | isbn=978-0-8135-0725-5 | page=[https://archive.org/details/ignitioninformal0000clar/page/9 9] | url-access=registration}}</ref> which is credited as having begun the space age, used ethanol as the main constituent of {{nowrap|''[[B-Stoff]]''}}. Under such nomenclature, the ethanol was mixed with 25% water to reduce the combustion chamber temperature.<ref>{{cite web | url=http://daviddarling.info/encyclopedia/V/V-2.html | title=The Internet Encyclopedia of Science: V-2 | last=Darling | first=David | name-list-style=vanc | access-date=27 July 2024}}</ref><ref name="braeunig">{{Cite web | title=Basics of Space Flight: Rocket Propellants | url=http://braeunig.us/space/propel.htm | access-date=11 March 2023 | website=braeunig.us}}</ref> The {{Nowrap|V-2's}} design team helped develop U.S. rockets following World War&nbsp;II, including the ethanol-fueled [[Redstone (rocket family)|Redstone rocket]], which launched the first U.S. astronaut on [[suborbital spaceflight]].<ref>{{cite web | title=A Brief History of Rocketry | url=http://science.ksc.nasa.gov/history/rocket-history.txt | work=NASA Historical Archive | archive-url=https://web.archive.org/web/20060805203537/http://science.ksc.nasa.gov/history/rocket-history.txt | archive-date=5 August 2006 | url-status=dead}}</ref><ref>{{Cite book | last1=Kuettner | first1=Joachim P. | author-link=Joachim Kuettner | url=https://ntrs.nasa.gov/citations/19630012071 | title=Mercury Project Summary Including Results of the Fourth Manned Orbital Flight: May 15 and 16, 1963 | last2=Bertram | first2=Emil | date=October 1963 | page=70 | chapter=Mercury-Redstone Launch-Vehicle development and performance | id=NASA-SP-45 | chapter-url=https://ntrs.nasa.gov/api/citations/19630012071/downloads/19630012071.pdf#page=78 | via=[[NASA Technical Reports Server|NTRS]]}}</ref> Alcohols fell into general disuse as more energy-dense rocket fuels were developed,<ref name="braeunig" /> although ethanol was used in recent experimental [[Light aircraft|lightweight]] [[Mark-III X-racer|rocket-powered racing aircraft]].<ref name="sdc20100426">{{cite web | url=http://www.space.com/businesstechnology/rocket-racing-tulsa-demonstration-100426.html | title=Rocket Racing League Unveils New Flying Hot Rod | first=Denise | last=Chow | name-list-style=vanc | website=[[Space.com]] | date=26 April 2010 | access-date=27 July 2024 | archive-url=https://web.archive.org/web/20140308035740/https://www.space.com/8290-rocket-racing-league-unveils-flying-hot-rod.html | archive-date=8 March 2014 | url-status=live}}</ref>

Commercial fuel cells operate on reformed natural gas, [[hydrogen]] or methanol. Ethanol is an attractive alternative due to its wide availability, low cost, high purity and low toxicity. There is a wide range of fuel cell concepts that have entered trials including [[direct-ethanol fuel cell]]s, auto-thermal reforming systems and thermally integrated systems. The majority of work is being conducted at a research level although there are a number of organizations at the beginning of the commercialization of ethanol fuel cells.<ref>{{cite journal | vauthors=Badwal SP, Giddey S, Kulkarni A, Goel J, Basu S | title=Direct ethanol fuel cells for transport and stationary applications – A comprehensive review | journal=Applied Energy | date=May 2015 | volume=145 | pages=80–103 | doi=10.1016/j.apenergy.2015.02.002 | doi-access=free | bibcode=2015ApEn..145...80B}}</ref>

Ethanol fireplaces can be used for home heating or for decoration. Ethanol can also be used as stove fuel for cooking.<ref>{{cite news | title=Can Ethanol Fireplaces Be Cozy? | first=Debra Jo | last=Immergut | date=3 December 2015 | url=https://www.wsj.com/articles/one-fire-please-hold-the-soot-1449170833 | access-date=2 March 2016 | work=The Wall Street Journal}}</ref><ref>{{cite journal | vauthors=Rajvanshi AK, Patil SM, Mendonca B | title=Low-concentration ethanol stove for rural areas in India | journal=Energy for Sustainable Development | volume=11 | issue=1 | date=March 2007 | pages=94–99 | doi=10.1016/S0973-0826(08)60568-2 | bibcode=2007ESusD..11...94R | url=https://www.sciencedirect.com/science/article/pii/S0973082608605682 | citeseerx=10.1.1.142.5846}}</ref>