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| {{Short description|Ethanol produced from corn biomass}} | |||
| ⚫ | {{Use dmy dates|date=May 2023}} | ||
| ] in the United States.]] | ] in the United States.]] | ||
| '''Corn ethanol''' is ] produced from ] that is used as a ]. Corn ethanol is produced by means of ] and ]. | |||
| '''Corn ethanol''' is ] produced from ] ] and is the main source of ], mandated to be blended with gasoline in the ]. Corn ethanol is produced by ] and ]. It is debatable whether the production and use of corn ethanol results in lower ] than gasoline.<ref>{{cite book | last=Smil | first=Vaclav | title=Energy Transitions: Global and National Perspectives | publisher=Praeger, an imprint of ABC-CLIO, LLC | location=Santa Barbara, California | year=2017 | isbn=978-1-4408-5324-1 | oclc=955778608 |page=162}}</ref><ref>{{Cite web|url=https://www.forbes.com/sites/jamesconca/2014/04/20/its-final-corn-ethanol-is-of-no-use/|title=It's Final -- Corn Ethanol Is of No Use|last=Conca|first=James|website=Forbes|access-date=2019-04-01}}</ref> Approximately 45% of U.S. corn ] are used for ] production.<ref>{{Cite web |title=USDA ERS – Feedgrains Sector at a Glance |url=https://www.ers.usda.gov/topics/crops/corn-and-other-feedgrains/feedgrains-sector-at-a-glance/ |access-date=2022-12-15 |website=ers.usda.gov}}</ref> | |||
| Corn ethanol is mainly used as an ] in gasoline to produce a ]. To a lesser extent, it is used as fuel for ] ].<ref name=EthanolUse>{{cite web |url=http://www.afdc.energy.gov/afdc/ethanol/market.html |title=Ethanol Market Penetration|publisher=Alternative Fuels and Advanced Vehicles Data Center, ]|accessdate=2006-06-25}}</ref><ref name="Ethanol">{{Cite book|last = Goettemoeller, Jeffrey; Adrian Goettemoeller|title = Sustainable Ethanol: Biofuels, Biorefineries, Cellulosic Biomass, Flex-Fuel Vehicles, and Sustainable Farming for Energy Independence|year = 2007|publisher = Prairie Oak Publishing, Maryville, Missouri |pages=42 |language=| isbn = 978-0-9786293-0-4 }}</ref> | |||
| == Uses == | |||
| Corn is the main ] used for producing ]. | |||
| ⚫ | {{Expand section|date=November 2018}} | ||
| Since 2001, corn ethanol production has increased by more than several times.<ref>{{Cite web|url=https://afdc.energy.gov/data/10339|title=Alternative Fuels Data Center: Maps and Data – U.S. Corn for Fuel Ethanol, Feed and Other Use|website=afdc.energy.gov|access-date=2019-04-16}}</ref> Out of 9.50 billions of bushels of corn produced in 2001, 0.71 billions of bushels were used to produce corn ethanol. Compared to 2018, out of 14.62 billions of bushels of corn produced, 5.60 billion bushels were used to produce corn ethanol, reported by the ]. Overall, 94% of ethanol in the United States is produced from corn.<ref name=":0">{{Cite web|url=https://afdc.energy.gov/fuels/ethanol_fuel_basics.html|title=Alternative Fuels Data Center: Ethanol Fuel Basics|website=afdc.energy.gov|access-date=2019-04-16}}</ref> | |||
| Currently, corn ethanol is mainly used in blends with ] to create mixtures such as ], ], and ]. ] is mixed into more than 98% of United States gasoline to reduce air pollution.<ref name=":0" /> Corn ethanol is used as an ] when mixed with ]. E10 and ] can be used in all engines without modification. However, blends like E85, with a much greater ] content, require significant modifications to be made before an engine can run on the mixture without damaging the engine.<ref name=":1">{{Cite web|url=http://large.stanford.edu/courses/2014/ph240/parry2/|title=Corn Ethanol Use in the Midwest|website=large.stanford.edu|access-date=2019-04-16}}</ref> Some vehicles that currently use ] fuel, also called ], include, the ], ], and ], among others.{{Citation needed|date=January 2021}} | |||
| ⚫ | ==Production process== | ||
| ⚫ | {{ |
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| ⚫ | ] plant in ].]] | ||
| The future use of corn ethanol as a main ] replacement is unknown. Corn ethanol has yet to be proven to be as cost effective as ] due to corn ethanol being much more expensive to create compared to ].<ref name=":1" /> Corn ethanol has to go through an extensive ] process before it can be used as a fuel source. One major drawback with corn ethanol, is the energy returned on energy invested (]), meaning the energy outputted in comparison to the energy required to output that energy. Compared to oil, with an 11:1 ], corn ethanol has a much lower ] of 1.5:1, which, in turn, also provides less mileage per gallon compared to gasoline.<ref>{{Cite journal|last1=Cleveland|first1=Cutler J.|last2=O’Connor|first2=Peter|last3=Hall|first3=Charles A. S.|last4=Guilford|first4=Megan C.|date=October 2011|title=A New Long Term Assessment of Energy Return on Investment (EROI) for U.S. Oil and Gas Discovery and Production|journal=Sustainability|volume=3|issue=10|pages=1866–1887|doi=10.3390/su3101866|doi-access=free}}</ref> In the future, as technology advances and oil becomes less abundant, the process of ] may require less energy, resulting in an ] closer to that of oil. Another serious problem with corn ethanol as a replacement for ], is the engine damage on standard vehicles. E10 contains ten percent ] and is acceptable for most vehicles on the road today, while ] contains fifteen percent ] and is usually prohibited for cars built before 2001.<ref name=":0" /> However, with the hope to replace ] in the future, ], which contains 85% ], requires engine modification before an engine can last while processing a high volume of ] for an extended period of time. Therefore, most older and modern day vehicles would become obsolete without proper engine modifications to handle the increase in ] from the high volume of ]. Also, most gas stations do not offer refueling of E85 vehicles. The ] reports that only 3,355 gas stations, out of 168,000, across the United States, offer ] refueling for ] vehicles.<ref>{{Cite web|url=https://afdc.energy.gov/fuels/ethanol_locations.html#/find/nearest?fuel=E85&country=U%20S|title=Alternative Fuels Data Center: Ethanol Fueling Station Locations|website=afdc.energy.gov|access-date=2019-04-16}}</ref> | |||
| There are two main types of corn ethanol production: ] and ]. The products of each type are utilized in different ways. | |||
| ⚫ | ==Production process== | ||
| In the dry milling process the entire corn kernel is ground into flour and referred to as "meal." The meal is then slurried by adding water. ] are added to the mash that convert starch to ], a simple sugar. ] is added to control the ] and as a nutrient for the ], which is added later. The mixture is processed at high-temperatures to reduce the bacteria levels and transferred and cooled in fermenters. This is where the yeast is added and conversion from sugar to ethanol and ] begins. | |||
| ⚫ | {{See also|Corn wet-milling|Dry milling and fractionation of grain|l1=}}] plant in ].]] | ||
| There are two main types of corn ethanol production: ] and ], which differ in the initial grain treatment method and co-products.<ref>{{Cite journal|last1=Bothast|first1=R. J.|last2=Schlicher|first2=M. A.|date=2014|title=Biotechnological processes for conversion of corn into ethanol|journal=Applied Microbiology and Biotechnology|volume=67|issue=1|pages=19–25|doi=10.1007/s00253-004-1819-8|pmid=15599517|s2cid=10019321|issn=0175-7598}}</ref> | |||
| The entire process takes between 40 to 50 hours, during which time the mash is kept cool and agitated in order to facilitate yeast activity. After the process is complete, everything is transferred to distillation columns where the ethanol is removed from the "stillage". The ethanol is dehydrated to about 200 proof using a molecular sieve system and a denaturant such as gasoline is added to render the product undrinkable. With this last addition, the process is complete and the product is ready to ship to gasoline retailers or terminals. The remaining stillage then undergoes a different process to produce a highly nutritious livestock feed. The carbon dioxide released from the process is also utilized to carbonate beverages and to aid in the manufacturing of dry ice. | |||
| === Dry milling === | |||
| The process of wet milling takes the corn grain and steeps it in a dilute combination of sulfuric acid and water for 24 to 48 hours in order to separate the grain into many components. The slurry mix then goes through a series of grinders to separate out the corn germ. Corn oil is a by-product of this process and is extracted and sold. The remaining components of fiber, gluten and starch are segregated out using screen, hydroclonic and centrifugal separators. | |||
| The vast majority (≈90%) of corn ethanol in the United States is produced by ].<ref>Ethanol Production and Distribution, Alternative Fuels Data Center, US Dept of Energy <http://www.afdc.energy.gov/fuels/ethanol_production.html></ref> In the ] process, the entire ] is ground into ], or "mash," which is then slurried by adding water.<ref>Verser, D. W.; Eggeman, T. J. Process for producing ethanol from corn dry milling. US7888082B2. https://patents.google.com/patent/US7888082B2/en</ref> ]s are added to the mash to hydrolyze the starch into ]s. ] is added to control the ] and as a nutrient for the ], which is added later. The mixture is processed at high-temperatures to reduce the bacteria levels. The mash is transferred and cooled in ]s. ] are added, which ferment the sugars into ] and ]. The entire process takes 40 to 50 hours, during which time the mash is kept cool and agitated to promote ] activity. The mash is then transferred to ]s, where the ] is removed from the ]. The ] is dehydrated to about 200 proof using a ] system. A ] such as ] is added to render the product undrinkable. The product is then ready to ship to gasoline retailers or terminals. The remaining ] is processed into a highly nutritious ] known as distiller's dried grains and solubles (DDGS).<ref>{{Cite web|url=https://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/agdex13760|title=Feeding Distillers Dried Grains with Solubles (DDGS) to Pigs|last=Section|first=Government of Alberta, Alberta Agriculture and Forestry, Livestock and Crops Division, Crop Research and Extension Branch, Livestock and Crop Research Extension|date=2011-11-01|website=www1.agric.gov.ab.ca|access-date=2018-11-23}}</ref> The ] released from the process is used to ] and to manufacture ] .{{Citation needed|date=January 2021}} | |||
| === Wet milling === | |||
| The gluten protein is dried and filtered to make a corn gluten- meals co-product and is highly sought after by poultry broiler operators as a feed ingredient. The steeping liquor produced is concentrated and dried with the fiber and sold as corn gluten feed to in the livestock industry. The heavy steep water is also sold as a feed ingredient and is used as an environmentally friendly alternative to salt in the winter months. The ] and remaining water can then be processed one of three ways: 1) fermented into ethanol, through a similar process as dry milling, 2) dried and sold as modified corn starch, or 3) made into corn syrup. | |||
| In ], the ] is separated into components by steeping in dilute ] for 24 to 48 hours.<ref>{{Citation|last1=Jackson|first1=David S.|title=Corn Wet Milling: Separation Chemistry and Technology|volume=38|date=1995|journal=Advances in Food and Nutrition Research|pages=271–300|publisher=Elsevier|doi=10.1016/s1043-4526(08)60085-6|pmid=15918293|isbn=9780120164387|last2=Shandera|first2=Donald L.}}</ref> The slurry mix then goes through a series of grinders to separate out the corn ]. The remaining components of fiber, ], and starch are segregated using screen, hydroclonic, and centrifugal separators. The ] and remaining water can be fermented into ] through a similar process as ], dried and sold as modified ], or made into ]. The ] protein and steeping liquor are dried to make a ] that is sold to the livestock industry. The heavy steep water is also sold as a feed ingredient and used as an alternative to salt in the winter months. ] is also extracted and sold.{{Citation needed|date=January 2021}} | |||
| ⚫ | ==Environmental issues== | ||
| The production of corn ethanol uses water in two ways – irrigation and processing. There are two types of ethanol processing, wet milling and dry milling, and the central difference between the two processes is how they initially treat the grain. In wet milling, the corn grain is steeped in water, and then separated for processing in the first step. Dry milling, which is more common, requires a different process. According to a report by the National Renewable Energy Laboratory, "Over 80% of U.S. ethanol is produced from corn by the dry grind process."{{citation needed|date=July 2012}} The dry grind process proceeds as follows: | |||
| "Corn grain is milled, then slurried with water to create 'mash.' Enzymes are added to the mash and this mixture is then cooked to hydrolyze the starch into glucose sugars. Yeast ferment these sugars into ethanol and carbon dioxide and the ethanol is purified through a combination of distillation and molecular sieve dehydration to create fuel ethanol. The byproduct of this process is known as distiller's dried grains and solubles (DDGS) and is used wet or dry as animal feed." | |||
| ⚫ | ==Environmental |
||
| {{See also|Ethanol fuel in the United States#Environmental and social impacts|l1=Environmental and social impacts of ethanol fuel in the U.S.}} | {{See also|Ethanol fuel in the United States#Environmental and social impacts|l1=Environmental and social impacts of ethanol fuel in the U.S.}} | ||
| Corn ethanol results in lower ] than ] and is fully ], unlike some ] such as ].<ref name="EERE"> {{webarchive|url=https://web.archive.org/web/20101215041537/http://www1.eere.energy.gov/biomass/ethanol_myths_facts.html|date=15 December 2010}}</ref> However, because energy to run many U.S. distilleries comes mainly from ] plants, there has been considerable debate on the ] of corn ethanol in replacing ]s. Additional controversy relates to the large amount of arable land required for crops and its impact on ] and ]. Other issues relate to ], water use for ] and processing, ], and emission ] for the ] of ethanol production.<ref name=WorldBank>{{cite web|url=http://siteresources.worldbank.org/INTWDR2008/Resources/2795087-1192112387976/WDR08_05_Focus_B.pdf |title=Biofuels: The Promise and the Risks, in World Development Report 2008 |publisher=The World Bank|year=2008|pages= 70–71|accessdate=2008-05-04}}</ref><ref name=Science08>{{cite journal|title=Use of U.S. Croplands for Biofuels Increases Greenhouse Gases Through Emissions from Land-Use Change|author=Timothy Searchinger|journal=]|volume=319 |issue=5867|pages=1238–1240|doi=10.1126/science.1151861|date=29 February 2008|pmid=18258860|bibcode=2008Sci...319.1238S|s2cid=52810681|display-authors=etal|doi-access=free}} Originally published online in Science Express on 7 February 2008. See Letters to ''Science'' by Wang and Haq. There are critics to these findings for assuming a worst-case scenario.</ref><ref name=Oxfam>{{cite web|url=http://www.oxfam.org/files/bp114-inconvenient-truth-biofuels-0806.pdf |title=Another Inconvenient Truth |publisher=] |date=28 June 2008 |accessdate=2008-08-06 |url-status=dead |archive-url=https://web.archive.org/web/20080819214631/http://www.oxfam.org/files/bp114-inconvenient-truth-biofuels-0806.pdf |archive-date=19 August 2008 }}Oxfam Briefing Paper 114, figure 2 pp.8</ref><ref name="Fargione08">{{cite journal|title=Land Clearing and the Biofuel Carbon Debt |author=Fargione|journal=]|volume=319 |issue=5867 |pages=1235–1238 |date=29 February 2008 |pmid= 18258862|doi= 10.1126/science.1152747|bibcode=2008Sci...319.1235F|last2= Hill|first2= J.|last3= Tilman|first3= D.|last4= Polasky|first4= S.|last5= Hawthorne|first5= P.|s2cid=206510225|display-authors=etal}} Originally published online in Science Express on 7 February 2008. There are rebuttals to these findings for assuming a worst-case scenario.</ref><ref name=ARBproposal>{{cite web|url= http://www.arb.ca.gov/regact/2009/lcfs09/lcfsisor1.pdf |title=Proposed Regulation to Implement the Low Carbon Fuel Standard. Volume I: Staff Report: Initial Statement of Reasons|publisher=]|date=5 March 2009|accessdate=2009-04-26}}</ref><ref>Youngquist, W. ], National Book company, Portland, OR, 499p.</ref><ref>{{Cite web |url=http://www.oilcrash.com/articles/pf_bio.htm |title=The dirty truth about biofuels |access-date=30 July 2010 |archive-date=4 December 2009 |archive-url=https://web.archive.org/web/20091204053139/http://www.oilcrash.com/articles/pf_bio.htm |url-status=dead }}</ref><ref></ref><ref name=Wfootprint2010>{{cite journal|title=The water footprint of biofuel production in the USA|last1=Powers|first1=Susan E|last2=Dominguez-Faus|first2=Rosa|last3=Alvarez|first3=Pedro JJ|date=March 2010|journal=Biofuels|volume=1|issue=2|pages=255–260|doi=10.4155/BFS.09.20|s2cid=130923687}}{{dead link|date=August 2017 |bot=InternetArchiveBot |fix-attempted=yes }}</ref><ref name=NRCWater>{{Cite book | author=], Committee on Water Implications of Biofuels Production in the United States|title = Water Implications of Biofuels Production in the United States| year = 2008 | publisher = ], Washington, D.C.| isbn = 978-0-309-11361-8}}</ref> | |||
| === Greenhouse gas emissions === | |||
| The initial assumption that ]s were good for the environment because they had a smaller ] is in debate over the contention that the production of grain alcohol, and therefore E85, may actually have a greater environmental impact than fossil fuel.<ref></ref><ref></ref> | |||
| ].|alt=|400x400px]]Several ] studies have found that corn ethanol reduces ] ] by up to 50 percent compared to gasoline.<ref name="EERE" /><ref>{{Cite journal|last1=Farrell|first1=Alexander E.|last2=Plevin|first2=Richard J.|last3=Turner|first3=Brian T.|last4=Jones|first4=Andrew D.|last5=O'Hare|first5=Michael|last6=Kammen|first6=Daniel M.|date=2006|title=Ethanol Can Contribute to Energy and Environmental Goals|journal=Science|volume=311|issue=5760|pages=506–508|doi=10.1126/science.1121416|issn=0036-8075|pmid=16439656|bibcode=2006Sci...311..506F|s2cid=16061891}}</ref><ref>{{Cite book|title=Two billion cars : driving toward sustainability|last=Daniel.|first=Sperling|date=2009|publisher=Oxford University Press|others=Gordon, Deborah, 1959–|isbn=9780199704095|location=Oxford|oclc=302414399}}</ref><ref name="Ianrnews.unl.edu">{{cite journal|last1=Liska|first1=Adam L.|last2=Yang|first2=Haishun S.|last3=Bremer|first3=Virgil R.|last4=Klopfenstein|first4=Terry J.|last5=Walters|first5=Daniel T.|last6=Erickson|first6=Galen E.|last7=Cassman|first7=Kenneth G.|date=2009|title=Improvements in Life Cycle Energy Efficiency and Greenhouse Gas Emissions of Corn‐Ethanol|journal=Journal of Industrial Ecology|volume=13|pages=58–74|doi=10.1111/j.1530-9290.2008.00105.x|s2cid=18630452|url=http://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1000&context=ncesrpub|doi-access=free}}</ref> However, more recent research based on an analysis of data from the first eight years of the US ]’s implementation suggests that corn ethanol produces more carbon emissions per unit of energy than gasoline, when factoring in fertilizer use and ].<ref>{{cite journal |last1=Lark |first1=Tyler |last2=Hendricks |first2=Nathan P. | first3=Aaron |last3=Smith | first4=Nicholas |last4=Pates | first5= Seth A. |last5=Spawn-Lee | first6= Matthew |last6=Bougie | first7=Eric G. |last7=Booth | first8= Christopher J. |last8=Kucharik | first9= Holly K. |last9=Gibbs |date=2022 |title=Environmental outcomes of the US Renewable Fuel Standard |journal=Proceedings of the National Academy of Sciences |volume=119 |issue=9 |doi=10.1073/pnas.2101084119 |pmid=35165202 |pmc=8892349 }}</ref> | |||
| ⚫ | Ethanol-blended fuels currently in the market – whether E10 or E85 – meet stringent tailpipe emission standards.<ref name="EERE" /> | ||
| That view says that one must consider: | |||
| * The impact of fertilizers and carbon requiring inputs vs carbon offsetting byproducts like ].<ref></ref> | |||
| * The carbon footprint of the agricultural machinery run to plant, harvest and apply chemicals.{{Citation needed|date=September 2010}} | |||
| * The environmental impact of those chemicals themselves, including fertilizers and pesticides necessary for efficient mass-production of the grains used. | |||
| * The larger amount of energy required to ship and process the grains and turn them into alcohol, versus the more efficient process of converting oil into gasoline or diesel.{{Citation needed|date=September 2010}} | |||
| * Even resources such as water, needed in huge amounts for grain production, can have serious environmental impact, including ground water depletion, pollution runoff, and algae blooms from waste runoff.<ref></ref> | |||
| === Croplands and land use === | |||
| The U.S. Department of Energy has published facts stating that current corn-based ethanol results in a 19% reduction in greenhouse gases, and is better for the environment than other gasoline additives such as MTBE.<ref name="EERE" /> | |||
| [[File:Corn vs Ethanol production.webp|thumb|300px|Corn vs ethanol production in the United States | |||
| {{legend|#FFD932|Total corn production (]s) (left)}} | |||
| {{legend|B51700|Corn used for ] (bushels) (left)}} | |||
| {{legend-line|#313131 solid 3px|Percent of corn used for Ethanol (right)}} | |||
| ]] | |||
| One of the main controversies involving corn ethanol production is the necessity for ] to grow the corn for ethanol, which is then ].<ref>{{Cite book|url=https://books.google.com/books?id=TXhQM0Qyol8C&q=rescuing+a+plant+under+stress+and+a+civilization+in+trouble&pg=PR7|title=Plan B: Rescuing a Planet Under Stress and a Civilization in Trouble|last=Brown|first=Lester Russell|date=2003|publisher=W. W. Norton & Company|isbn=9780393325232}}</ref> In the United States, 40% of the acreage designated for corn grain is used for corn ethanol production, of which 25% was converted to ethanol after accounting for co-products, leaving only 60% of the crop yield for human or animal consumption.<ref name="Mumm 2014 61">{{Cite journal |last1=Mumm |first1=Rita H |last2=Goldsmith |first2=Peter D |last3=Rausch |first3=Kent D |last4=Stein |first4=Hans H |date=2014 |title=Land usage attributed to corn ethanol production in the United States: sensitivity to technological advances in corn grain yield, ethanol conversion, and co-product utilization |journal=Biotechnology for Biofuels |volume=7 |issue=1 |pages=61 |doi=10.1186/1754-6834-7-61 |issn=1754-6834 |pmc=4022103 |pmid=24725504 |quote=Although 40.5% of corn grain was channeled to ethanol processing in 2011, only 25% of US corn acreage was attributable to ethanol when accounting for feed co-product utilization. |doi-access=free }}</ref> | |||
| Growing corn to fuel internal combustion vehicles is a highly inefficient use of land. A ] generating electricity to power an electric vehicle would power around 85 times as much distance as corn ethanol grown on the same area.<ref>{{Cite web |date=January 19, 2023 |title=Corn Ethanol vs. Solar: Land Use Comparison |url=https://www.cleanwisconsin.org/wp-content/uploads/2023/01/Corn-Ethanol-Vs.-Solar-Analysis-V3-9-compressed.pdf |website=Clean Wisconsin}}</ref> | |||
| Ethanol produced today results in fewer greenhouse gas (GHG) emissions than gasoline and is fully biodegradable, unlike some fuel additives. | |||
| * Today, on a life cycle basis, ethanol produced from corn results in about a 20 percent reduction in GHG emissions relative to gasoline. With improved efficiency and use of renewable energy, this reduction could be as much as 52 percent.<ref name="EERE" /> | |||
| * In the future, ethanol produced from cellulose has the potential to cut life cycle GHG emissions by up to 86 percent relative to gasoline.<ref name="EERE" /> | |||
| ⚫ | |||
| * Ethanol readily biodegrades without harm to the environment, and is a safe, high-performance replacement for fuel additives such as MTBE.<ref name="EERE" /> | |||
| ⚫ | == Economic impact of corn ethanol == | ||
| Others<ref name="Ianrnews.unl.edu"/> say that ethanol from corn, as a fuel available now, and cellulosic ethanol in the future, are both much better fuels for the environment.<ref name="EERE"></ref> Ethanol derived from sugar-beet as used in Europe or sugar-cane as grown in Brazil in industrial scale is generally seen as having a very positive CO<sub>2</sub> balance with up to 80% reduction in ] CO<sub>2</sub>. | |||
| ⚫ | The ] (RFA), the ethanol industry's lobbying group, claims that ethanol production increases the price of corn by increasing demand. The RFA claims that ethanol production has positive economic effect for US farmers, but it does not elaborate on the effect for other populations where field corn is part of the staple diet. An RFA lobby document states that "In a January 2007 statement, the USDA Chief Economist stated that farm program payments were expected to be reduced by some $6 billion due to the higher value of a bushel of corn.<ref>{{cite web|url=http://www.ethanolrfa.org/pages/ethanol-facts-agriculture |title=Ethanol Facts: Agriculture |publisher=ethanolrfa.org |date=12 January 2010 |accessdate=2010-04-04}}</ref> Corn production in 2009 reached over 13.2 billion bushels, and a per acre yield jumped to over 165 bushels per acre.<ref>{{cite web |url=http://www.nass.usda.gov/Newsroom/2010/01_12_2010.asp |title=2009 Crop Year is One for the Record Books, USDA Reports |publisher=Nass.usda.gov |date=12 January 2010 |accessdate=2010-04-04 |url-status=dead |archive-url=https://web.archive.org/web/20100114051806/http://www.nass.usda.gov/Newsroom/2010/01_12_2010.asp |archive-date=14 January 2010 }}</ref> | ||
| In the United States, 5.05 billion bushels of corn were used for ] production out of 14.99 billion bushels produced in 2020, according to ] data.<ref name="afdc.energy.gov">{{Cite web|url=https://afdc.energy.gov/data/10339|title=Alternative Fuels Data Center: Maps and Data – Corn Production and Portion Used for Fuel Ethanol|website=afdc.energy.gov|access-date=2019-08-29}}</ref> According to the U.S. Department of Energy's Alternative Fuels Data Center, "The increased ethanol seems to have come from the increase in overall corn production and a small decrease in corn used for animal feed and other residual uses. The amount of corn used for other uses, including human consumption, has stayed fairly consistent from year to year."<ref name="afdc.energy.gov"/> | |||
| This does not prove there was not an impact on food supplies: Since U.S. corn production doubled (approximately) between 1987 and 2018, it is probable that some cropland previously used to grow other food crops is now used to grow corn. It is also possible or probable that some marginal land has been converted or returned to agricultural use. That may have negative environmental impacts.{{Citation needed|date=January 2021}} | |||
| ==Alternative biomass for ethanol== | |||
| A ] study in 2009 showed corn ethanol directly emits 51% less greenhouse gas than gasoline. However this study does not take into account the greenhouse gasses involved in production and transportation<ref name="Ianrnews.unl.edu">{{cite web|url=http://ianrnews.unl.edu/static/0901220.shtml |title=IANR News: UNL Research: Corn Ethanol Emits 51 Percent Less Greenhouse Gas Than Gasoline |doi=10.1111/j.1530-9290.2008.00105.x |publisher=Ianrnews.unl.edu |date=2009-01-22 |accessdate=2010-04-04}}</ref> | |||
| Remnants from food production such as ] could be used to produce ethanol instead of food corn. Ethanol derived from sugar-beet as used in Europe or sugar-cane in Brazil has up to 80% reduction in ] ]. The use of ] to produce ] is considered second generation ] that are considered by some to be a solution to the food versus fuel debate, and has the potential to cut life cycle ] by up to 86 percent relative to gasoline.<ref name="EERE" /> | |||
| ⚫ | |||
| The use of ethanol for fuel has had a damaging impact on food markets, especially in poorer countries. In the United States, ethanol is mostly made from yellow corn, and as the market boomed for alternative fuel, yellow corn went up in price. Many farmers saw the potential to make more money, and switched from white corn to yellow corn. White corn is the main ingredient of tortillas in Mexico, and as the supply dropped, the price doubled, making the base of most Mexican foods unaffordable.<ref>{{cite web|url=http://medialab.blogs.com/our_ethanol_debate/2007/03/economic_impact.html |title=Our Ethanol Debate: Economic Impact of Ethanol Production on Corn |publisher=Medialab.blogs.com |date= |accessdate=2010-04-04}}</ref> Many people{{Who|date=November 2009}} see this as unacceptable, and want no overlap between food crops and fuel crops.<ref>{{cite web|url=http://www.alternative-energy-news.info/technology/biofuels/ |title=Biofuels - Solid, liquid, or gas fuels made from biomass |publisher=Alternative-energy-news.info |date= |accessdate=2010-04-04}}</ref><ref>{{cite web|url=http://willtaft.com/energy-use/use-food-crops-for-food-not-fuel/ |title=Should We Use Food Crops For Food, Not Fuel? |publisher=Willtaft.com |date=2008-05-14 |accessdate=2010-04-04}}</ref> Others{{Who|date=November 2009}} point out that the earth is thought to be able to support double the current human population, and press that the resources available, such as unused farmable land, should be better handled.<ref>{{cite web|url=http://www.mindsinmotion.net/index.php/mimv34/themes/alternative_fuels/opinion/the_world_food_crisis_in_perspective |title=The world food crisis in perspective / Opinion / Alternative Fuels / Themes / Welcome |publisher=Minds in Motion |date=2008-11-17 |accessdate=2010-04-04}}</ref> | |||
| ⚫ | The Renewable Fuels Association |
||
| Corn production in 2009 reached over 13.2 billion bushels, and a per acre yield jumped to over 165 bushels per acre.<ref>{{cite web|url=http://www.nass.usda.gov/Newsroom/2010/01_12_2010.asp |title=2009 Crop Year is One for the Record Books, USDA Reports |publisher=Nass.usda.gov |date=2010-01-12 |accessdate=2010-04-04}}</ref> | |||
| ==Alternatives to corn as a feedstock== | |||
| Remnants from food production such as corn stover could be used to produce ethanol instead of food corn. The use of cellulosic biomass to produce ethanol is a new trend in biofuel production. Fuels from these products are considered second generation biofuels and are considered by some to be a solution to the food verses fuel debate. The possibility of using this material has been acknowledged by the scientific community and the political community as well. | |||
| ==See also== | ==See also== | ||
| *] | |||
| *] | *] | ||
| *] | *] | ||
| Line 70: | Line 60: | ||
| ==External links== | ==External links== | ||
| * (]). | * (]). | ||
| *The End of Cheap Food. (Cover Story). 2007 Economist 385(8558): |
*The End of Cheap Food. (Cover Story). 2007 Economist 385(8558):11–12. | ||
| *Energy Policy Act of 2005. 2005 Public Law 109-58. | *Energy Policy Act of 2005. 2005 Public Law {{nat|109-58}}. | ||
| *Pimentel, David. 2009 Corn Ethanol as Energy. Harvard International Review 31(2): |
*Pimentel, David. 2009 Corn Ethanol as Energy. Harvard International Review 31(2):50–52. | ||
| *Scully, Vaughan. 2007 Effects of the Biofuel Boom. BusinessWeek Online:26-26. | *Scully, Vaughan. 2007 Effects of the Biofuel Boom. BusinessWeek Online:26-26. | ||
| *Waltz, Emily. 2008 Cellulosic Ethanol Booms Despite Unproven Business Models. Nature Biotechnology 26(1): |
*Waltz, Emily. 2008 Cellulosic Ethanol Booms Despite Unproven Business Models. Nature Biotechnology 26(1):8–9. | ||
| * | |||
| * ]. | |||
| ⚫ | {{Use dmy dates|date= |
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| {{DEFAULTSORT:Corn Ethanol}} | {{DEFAULTSORT:Corn Ethanol}} | ||
| ] | ] | ||
| ] | ] | ||
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Latest revision as of 02:33, 21 November 2024
Ethanol produced from corn biomass
Corn ethanol is ethanol produced from corn biomass and is the main source of ethanol fuel in the United States, mandated to be blended with gasoline in the Renewable Fuel Standard. Corn ethanol is produced by ethanol fermentation and distillation. It is debatable whether the production and use of corn ethanol results in lower greenhouse gas emissions than gasoline. Approximately 45% of U.S. corn croplands are used for ethanol production.
Uses
 | This section needs expansion. You can help by adding to it. (November 2018) |
Since 2001, corn ethanol production has increased by more than several times. Out of 9.50 billions of bushels of corn produced in 2001, 0.71 billions of bushels were used to produce corn ethanol. Compared to 2018, out of 14.62 billions of bushels of corn produced, 5.60 billion bushels were used to produce corn ethanol, reported by the United States Department of Energy. Overall, 94% of ethanol in the United States is produced from corn.
Currently, corn ethanol is mainly used in blends with gasoline to create mixtures such as E10, E15, and E85. Ethanol is mixed into more than 98% of United States gasoline to reduce air pollution. Corn ethanol is used as an oxygenate when mixed with gasoline. E10 and E15 can be used in all engines without modification. However, blends like E85, with a much greater ethanol content, require significant modifications to be made before an engine can run on the mixture without damaging the engine. Some vehicles that currently use E85 fuel, also called flex fuel, include, the Ford Focus, Dodge Durango, and Toyota Tundra, among others.
The future use of corn ethanol as a main gasoline replacement is unknown. Corn ethanol has yet to be proven to be as cost effective as gasoline due to corn ethanol being much more expensive to create compared to gasoline. Corn ethanol has to go through an extensive milling process before it can be used as a fuel source. One major drawback with corn ethanol, is the energy returned on energy invested (EROI), meaning the energy outputted in comparison to the energy required to output that energy. Compared to oil, with an 11:1 EROI, corn ethanol has a much lower EROI of 1.5:1, which, in turn, also provides less mileage per gallon compared to gasoline. In the future, as technology advances and oil becomes less abundant, the process of milling may require less energy, resulting in an EROI closer to that of oil. Another serious problem with corn ethanol as a replacement for gasoline, is the engine damage on standard vehicles. E10 contains ten percent ethanol and is acceptable for most vehicles on the road today, while E15 contains fifteen percent ethanol and is usually prohibited for cars built before 2001. However, with the hope to replace gasoline in the future, E85, which contains 85% ethanol, requires engine modification before an engine can last while processing a high volume of ethanol for an extended period of time. Therefore, most older and modern day vehicles would become obsolete without proper engine modifications to handle the increase in corrosiveness from the high volume of ethanol. Also, most gas stations do not offer refueling of E85 vehicles. The United States Department of Energy reports that only 3,355 gas stations, out of 168,000, across the United States, offer ethanol refueling for E85 vehicles.
Production process
See also: Corn wet-milling and Dry milling and fractionation of grain
There are two main types of corn ethanol production: dry milling and wet milling, which differ in the initial grain treatment method and co-products.
Dry milling
The vast majority (≈90%) of corn ethanol in the United States is produced by dry milling. In the dry milling process, the entire corn kernel is ground into flour, or "mash," which is then slurried by adding water. Enzymes are added to the mash to hydrolyze the starch into simple sugars. Ammonia is added to control the pH and as a nutrient for the yeast, which is added later. The mixture is processed at high-temperatures to reduce the bacteria levels. The mash is transferred and cooled in fermenters. Yeast are added, which ferment the sugars into ethanol and carbon dioxide. The entire process takes 40 to 50 hours, during which time the mash is kept cool and agitated to promote yeast activity. The mash is then transferred to distillation columns, where the ethanol is removed from the silage. The ethanol is dehydrated to about 200 proof using a molecular sieve system. A denaturant such as gasoline is added to render the product undrinkable. The product is then ready to ship to gasoline retailers or terminals. The remaining silage is processed into a highly nutritious livestock feed known as distiller's dried grains and solubles (DDGS). The carbon dioxide released from the process is used to carbonate beverages and to manufacture dry ice .
Wet milling
In wet milling, the corn grain is separated into components by steeping in dilute sulfurous acid for 24 to 48 hours. The slurry mix then goes through a series of grinders to separate out the corn germ. The remaining components of fiber, gluten, and starch are segregated using screen, hydroclonic, and centrifugal separators. The corn starch and remaining water can be fermented into ethanol through a similar process as dry milling, dried and sold as modified corn starch, or made into corn syrup. The gluten protein and steeping liquor are dried to make a corn gluten meal that is sold to the livestock industry. The heavy steep water is also sold as a feed ingredient and used as an alternative to salt in the winter months. Corn oil is also extracted and sold.
Environmental issues
See also: Environmental and social impacts of ethanol fuel in the U.S.Corn ethanol results in lower greenhouse gas emissions than gasoline and is fully biodegradable, unlike some fuel additives such as MTBE. However, because energy to run many U.S. distilleries comes mainly from coal plants, there has been considerable debate on the sustainability of corn ethanol in replacing fossil fuels. Additional controversy relates to the large amount of arable land required for crops and its impact on grain supply and direct and indirect land use change effects. Other issues relate to pollution, water use for irrigation and processing, energy balance, and emission intensity for the full life cycle of ethanol production.
Greenhouse gas emissions
.JPG)
Several full life cycle studies have found that corn ethanol reduces well-to-wheel greenhouse gas emissions by up to 50 percent compared to gasoline. However, more recent research based on an analysis of data from the first eight years of the US Renewable Fuel Standard’s implementation suggests that corn ethanol produces more carbon emissions per unit of energy than gasoline, when factoring in fertilizer use and land use change.
Ethanol-blended fuels currently in the market – whether E10 or E85 – meet stringent tailpipe emission standards.
Croplands and land use
One of the main controversies involving corn ethanol production is the necessity for arable cropland to grow the corn for ethanol, which is then not available to grow corn for human or animal consumption. In the United States, 40% of the acreage designated for corn grain is used for corn ethanol production, of which 25% was converted to ethanol after accounting for co-products, leaving only 60% of the crop yield for human or animal consumption.
Growing corn to fuel internal combustion vehicles is a highly inefficient use of land. A solar farm generating electricity to power an electric vehicle would power around 85 times as much distance as corn ethanol grown on the same area.
Economic impact of corn ethanol
The Renewable Fuels Association (RFA), the ethanol industry's lobbying group, claims that ethanol production increases the price of corn by increasing demand. The RFA claims that ethanol production has positive economic effect for US farmers, but it does not elaborate on the effect for other populations where field corn is part of the staple diet. An RFA lobby document states that "In a January 2007 statement, the USDA Chief Economist stated that farm program payments were expected to be reduced by some $6 billion due to the higher value of a bushel of corn. Corn production in 2009 reached over 13.2 billion bushels, and a per acre yield jumped to over 165 bushels per acre. In the United States, 5.05 billion bushels of corn were used for ethanol production out of 14.99 billion bushels produced in 2020, according to USDA data. According to the U.S. Department of Energy's Alternative Fuels Data Center, "The increased ethanol seems to have come from the increase in overall corn production and a small decrease in corn used for animal feed and other residual uses. The amount of corn used for other uses, including human consumption, has stayed fairly consistent from year to year." This does not prove there was not an impact on food supplies: Since U.S. corn production doubled (approximately) between 1987 and 2018, it is probable that some cropland previously used to grow other food crops is now used to grow corn. It is also possible or probable that some marginal land has been converted or returned to agricultural use. That may have negative environmental impacts.
Alternative biomass for ethanol
Remnants from food production such as corn stover could be used to produce ethanol instead of food corn. Ethanol derived from sugar-beet as used in Europe or sugar-cane in Brazil has up to 80% reduction in well-to-wheel carbon dioxide. The use of cellulosic biomass to produce ethanol is considered second generation biofuel that are considered by some to be a solution to the food versus fuel debate, and has the potential to cut life cycle greenhouse gas emissions by up to 86 percent relative to gasoline.
See also
References
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External links
- Better Than Corn? Algae Set to Beat Out Other Biofuel Feedstocks (Worldwatch Institute).
- The End of Cheap Food. (Cover Story). 2007 Economist 385(8558):11–12.
- Energy Policy Act of 2005. 2005 Public Law 109-58.
- Pimentel, David. 2009 Corn Ethanol as Energy. Harvard International Review 31(2):50–52.
- Scully, Vaughan. 2007 Effects of the Biofuel Boom. BusinessWeek Online:26-26.
- Waltz, Emily. 2008 Cellulosic Ethanol Booms Despite Unproven Business Models. Nature Biotechnology 26(1):8–9.
- Cornstarch Substitute
- Martin,Jeremy. 2017. Fueling a Clean Transportation Future. Union of Concerned Scientists.