Aviation biofuel: Difference between revisions

An '''aviation biofuel''' (also known as '''bio-jet fuel'''<ref name=IU4dec2020>{{Cite web |date= 2020-12-04 |access-date= 2022-12-12|title= Sustainable aviation fuel market demand drives new product launches |url=https://investableuniverse.com/2020/12/04/sustainable-aviation-fuel-argus-price-gunvor-group/ |website= [[Investable Universe]]}} Note: ''[https://investableuniverse.com/home/about/ Investable Universe>About]''</ref> or '''bio-aviation fuel''' (BAF);<ref name="Doliente2020">{{Cite journal |last= Doliente |first= Stephen S. |display-authors=etal |date= 10 July 2020 |title= Bio-aviation Fuel: A Comprehensive Review and Analysis of the Supply Chain Components |journal= Frontiers in Energy Research |volume= 8 |doi= 10.3389/fenrg.2020.00110 |language= English |doi-access= free |url= https://purehost.bath.ac.uk/ws/files/205375761/Doliente_et_al_2020_Accepted_Manuscript_Frontiers_in_Energy_Research.pdf }}</ref>) is a [[biofuel]] used to power [[aircraft]] and is said to be a [[Aviation biofuel#Sustainable aviation fuels|sustainable aviation fuel]] (SAF).<!-- is this correct?? it seems wrong to say that aviation biofuel is SAF --> The [[International Air Transport Association]] (IATA) considers it a key element toin reducing the [[carbon footprint]] within the [[environmental impact of aviation]].<ref>{{cite web |url= https://www.iata.org/en/programs/environment/sustainable-aviation-fuels/ |title= Developing Sustainable Aviation Fuel (SAF) |publisher= IATA}}</ref> Aviation biofuel couldis helpused to [[Low-carbon economy|decarbonize]] medium- and long-haul air travel. generatingThese types of travel generate the most emissions, and could extend the life of older aircraft types by lowering their carbon footprint. The jargon '''syntheticSynthetic paraffinic kerosene''' (SPK) refers to any non-petroleum-based fuel designed to replace kerosene [[jet fuel]], which areis often, but not always, made from biomass.

Aviation biofuel can be produced from plant or animal sources such as ''[[Jatropha]]'', [[algae]], [[tallows]], waste oils, [[palm oil]], [[Babassu oil|Babassu]], and ''[[Camelina]]'' (bio-SPK); from solid [[biomass]] using [[pyrolysis]] processed with a [[Fischer–Tropsch process]] (FT-SPK); with an [[Alcohol (chemistry)|alcohol]]-to-jet (ATJ) process from waste fermentation; or from [[synthetic biology]] through a [[Chemical reactor|solar reactor]]. Small piston engines can be modified to burn [[ethanol]].<!--ref name=SDSU2016-->

[[Sustainable biofuel]]s do not compete with [[food crop]]s, prime [[agricultural land]], [[natural forest]] or fresh water.{{Explain|reason=As this extremely broad claim sounds quite unlikely to be true, it should be explained what leads to it. Currently it sounds like an advertisement.|date=November 2023}} They are an alternative to [[electrofuels]].<ref>{{Cite web|author=Mark Pilling|title=How sustainable fuel will help power aviation's green revolution|url=https://www.flightglobal.com/flight-international/how-sustainable-fuel-will-help-power-aviations-green-revolution/143044.article|date=2021-03-25|website=Flight Global}}</ref> Sustainable aviation fuel is certified as being [[sustainable]] by a third-party organisation.<section end="summary" />

Plants absorb [[Carbon Dioxide|carbon dioxide]] as they grow, meaningtherefore plant-based biofuels emit only the same amount of [[greenhouse gas]]es as they had previously absorbed. Biofuel production, processing, and transport, however, emit greenhouse gases, reducing the emissions savings.<ref name="Doliente2020" /> Biofuels with the most emission savings are those derived from photosynthetic algae (98% savings) although the technology is not developed, and those from [[Second-generation biofuels|non-food crops and forest residues]] (91–95% savings).<ref name="Doliente2020" />

[[Jatropha oil]], a non-food oil used as a biofuel, should lowerlowers {{chem2|CO2}} emissions by 50–80% compared to Jet-A1, a [[kerosene]]-based fuel.<ref name=AImar2009>{{cite magazine |title= A Greener Future? |magazine= [[Aircraft Illustrated]] |date= March 2009}}</ref> Jatropha, used for [[biodiesel]], can thrive on [[marginal land]] where most plants would produce low [[crop yield|yield]]s.<ref>{{cite news |author= Ron Oxburgh |url= https://www.theguardian.com/commentisfree/2008/feb/28/alternativeenergy.biofuels |title= Through biofuels we can reap the fruits of our labours |newspaper= [[The Guardian]] |date= 28 February 2008}}</ref><ref>{{cite news |author= Patrick Barta |title= As Biofuels Catch On, Next Task Is to Deal With Environmental, Economic Impact |url= https://www.wsj.com/articles/SB120631198956758087 |newspaper= [[Wall Street Journal]] |date= 24 March 2008 |url-access= subscription}}</ref> A [[life cycle assessment]] on jatropha estimated that biofuels could reduce greenhouse gas emissions by up to 85% if former agro-pastoral land is used, or increase emissions by up to 60% if natural woodland is converted.<ref>{{Cite journal | last1 = Bailis | first1 = R. E. | last2 = Baka | first2 = J. E. | doi = 10.1021/es1019178 | title = Greenhouse Gas Emissions and Land Use Change from Jatropha Curcas-Based Jet Fuel in Brazil | journal = Environmental Science & Technology | volume = 44 | issue = 22 | pages = 8684–91 | year = 2010 | pmid = 20977266| bibcode = 2010EnST...44.8684B }}</ref>

[[Palm oil]] cultivation is constrained by scarce land resources and its expansion to forestland causes [[deforestation]] and [[biodiversity loss]], andalong with direct and indirect emissions due to [[land-use change]].<ref name="Doliente2020" /> [[Neste Corporation]]'s renewable products include a refining [[byproduct|residue]] of food-grade palm oil, the oily waste [[Resource recovery|skimmed]] from the palm oil mill's [[wastewater]]. Other Neste sources are UCO ([[used cooking oil]]) from [[Deep fryer#Oil filtration|deep fryers]] and animal fats.<ref>{{Cite web|url=https://www.neste.com/products/all-products/raw-materials/waste-and-residues|title=Waste and residues as raw materials |date=15 May 2020 |publisher=Neste Corporation website}}</ref> [https://www.neste.com/en-us/products-and-innovation/sustainable-aviation/sustainable-aviation-fuel Neste's sustainable aviation fuel] is used by [[Lufthansa]];<ref>{{Cite press release|url=https://www.neste.com/releases-and-news/aviation/neste-and-lufthansa-collaborate-and-aim-more-sustainable-aviation|title=Neste and Lufthansa collaborate and aim for a more sustainable aviation|date=October 2, 2019|publisher=Neste Corporation website}}</ref> [[Air France]] and [[KLM]] announced 2030 SAF targets in 2022<ref>{{Cite press release|url=https://news.klm.com/klm-groups-co2-emission-reduction-targets-for-2030-approved-by-sbti/|title=KLM Group's CO2 emission reduction targets for 2030 approved by SBTi|date=16 December 2022 |publisher=KLM website |access-date=2023-01-02}}</ref> and announcedincluding multi-year purchase contracts totallingtotaling over 2.4 million tonnes of SAF from Neste, [[TotalEnergies]], and [[DG Fuels]].<ref>{{Cite news| url=https://www.reuters.com/business/energy/totalenergies-air-france-klm-agree-sustainable-jet-fuel-deal-2022-12-05/|title=TotalEnergies and Air France KLM agree sustainable jet fuel deal|date=5 December 2022 |publisher=[[Reuters]] |access-date=2023-01-02}}</ref>

Aviation fuel from wet waste-derived feedstock ("VFA-SAF") provides an additional environmental benefit. Wet waste consists of waste from landfills, sludge from wastewater treatment plants, agricultural waste, greases, and fats. Wet waste can be converted to volatile fatty acids (VFA's), which then can be catalytically upgraded to SAF. Wet waste is a low-cost and plentiful feedstock, with the potential to replace 20% of US fossil jet fuel consumption.<ref name="auto">{{Cite journal |last1=Huq |first1=Nabila A. |last2=Hafenstine |first2=Glenn R. |last3=Huo |first3=Xiangchen |last4=Nguyen |first4=Hannah |last5=Tifft |first5=Stephen M. |last6=Conklin |first6=Davis R. |last7=Stück |first7=Daniela |last8=Stunkel |first8=Jim |last9=Yang |first9=Zhibin |last10=Heyne |first10=Joshua S. |last11=Wiatrowski |first11=Matthew R. |last12=Zhang |first12=Yimin |last13=Tao |first13=Ling |last14=Zhu |first14=Junqing |last15=McEnally |first15=Charles S. |date=2021-03-30 |title=Toward net-zero sustainable aviation fuel with wet waste-derived volatile fatty acids |journal=Proceedings of the National Academy of Sciences of the United States of America |volume=118 |issue=13 |pages=e2023008118 |doi=10.1073/pnas.2023008118 |issn=1091-6490 |pmc=8020759 |pmid=33723013 |doi-access=free |bibcode=2021PNAS..11823008H }}</ref> This eliminateslessens the need to grow crops specifically for fuel, which is in itself is energy intensive and increases total {{chem2|CO2}} emissions throughout its life cycle. As of 2023, 90% of biofuel is made from oilseed and sugarcane which are grown for this purpose only.<ref>{{Cite web |title=Biodiesel Market Size, Share & Trends Analysis Report, 2030 |url=https://www.grandviewresearch.com/industry-analysis/biodiesel-market |access-date=2023-11-17 |website=www.grandviewresearch.com |language=en}}</ref> Wet waste-derived feedstocks for SAF divert waste from landfills, this action. aloneDiversion has the potential to [https://www.epa.gov/ghgemissions/inventory-us-greenhouse-gas-emissions-and-sinks eliminate 17% of the U.S.'s totalUS methane emissions] across all sectors. VFA-SAF's carbon footprint is 165% lower than fossil aviation fuel.<ref name="auto"/> This technology is in its infancy; although several start-ups are working to make this a viable solution. [https://www.alderrenewables.com/ Alder Renewables], [https://www.bioveritas.com/ BioVeritas], and [https://chaincraft.com/ ChainCraft] are a few organizations committed to this.

NASA has determined that 50% aviation biofuel mixture can cut [[particulate emissions]] caused by air traffic by 50–70%.<ref>{{cite news |url= http://www.flyingmag.com/nasa-confirms-biofuels-reduce-jet-emissions |work= [[Flying (magazine)|Flying magazine]] |title= NASA confirms biofuels reduce jet emissions |date= March 23, 2017}} Note: Firefox 'does not trust' the weblink 2022-12-22.</ref> Biofuels do not contain sulfur compounds and thus do not emit [[sulfur dioxide]].{{CiteCitation needed|date=December 2022}}

==TimelineHistory==

{{see also|Aviation biofuel demonstrations}}{{Update section|date=March 2024|reason=Lots of plans announced years ago. No info on whether the plans were carried out.}}

By June 2011, the revised ''Specification for Aviation Turbine Fuel Containing Synthesized Hydrocarbons'' ([[ASTM]] D7566) allowed commercial airlines to blend up to 50% biofuels with conventional jet fuel.<ref>{{cite news |url=http://www.renewableenergyworld.com/rea/news/article/2011/07/50-percent-biofuels-now-allowed-in-jet-fuel |title=50 Percent Biofuels Now Allowed in Jet Fuel |date=1 July 2011 |work=[[Renewable Energy World]] |access-date=6 December 2020 |archive-date=8 June 2020 |archive-url=https://web.archive.org/web/20200608062153/https://www.renewableenergyworld.com/2011/07/01/50-percent-biofuels-now-allowed-in-jet-fuel/ |url-status=dead }}</ref> The safety and performance of jet fuel used in passenger flights is certified by [[ASTM International]].<ref name=ASTMsep2011>{{cite web |url= http://www.astm.org/SNEWS/SO_2011/enright_so11.html |title= Aviation Fuel Standard Takes Flight |quote= D7566 Revision Adds Bioderived Components |publisher= ASTM |date= September–October 2011}}</ref> Biofuels were approved for commercial use after a multi-year technical review from [[Aerospace manufacturer|aircraft maker]]s, [[List of turbofan manufacturers|engine manufacturer]]s and [[oil companies]].<ref>{{cite news |url= https://www.bloomberg.com/news/2011-07-01/airlines-win-approval-to-use-plant-based-biofuels-on-commercial-flights.html |title= Airlines Win Approval to Use Biofuels for Commercial Flights |date= 1 July 2011 |agency= Bloomberg}}</ref> Thereafter some airlines experimented with biofuels on commercial flights.<ref>{{cite news |url= https://www.nytimes.com/2011/10/10/business/global/10iht-green10.html?_r=1 |title= Airlines Weigh the Advantages of Biofuels |newspaper= NY Times |date= 9 Oct 2011 |author= Bettina Wassener}}</ref> As of July 2020, seven annexes to D7566 were published, including various biofuel types:<ref>{{cite news|url=https://www.greencarcongress.com/2020/05/20200514-ihi.html|title=ASTM approves 7th annex to D7566 sustainable jet fuel specification: HC-HEFA|date=May 14, 2020|journal=Green Car Congress|access-date=August 8, 2021}}</ref>

In December 2011, the [[FAA]] awarded US$7.7 million to eight companies to develop [[Substitute good|drop-in]] sustainable fuels, especially from [[Alcohol (chemistry)|alcohol]]s, [[sugar]]ssugars, [[biomass]], and [[organic matter]] such as [[pyrolysis oil]]s, within its {{abbr|CAAFI|Commercial Aviation Alternative Fuel Initiative}} and {{abbr|CLEEN|Continuous Lower Emissions, Energy and Noise}} programs.<ref>{{cite news |url=http://www.renewableenergyworld.com/rea/news/article/2011/12/faa-awards-7-7-million-for-advancement-of-aviation-biofuels |title=FAA Awards $7.7 Million for Advancement of Aviation Biofuels |author=Meg Cichon |date=2 December 2011 |work=[[Renewable Energy World]] |access-date=6 December 2020 |archive-date=28 March 2014 |archive-url=https://web.archive.org/web/20140328195458/http://www.renewableenergyworld.com/rea/news/article/2011/12/faa-awards-7-7-million-for-advancement-of-aviation-biofuels |url-status=dead }}</ref>

FromBiofuel 2014,provider [[Solena Group|Solena]] planned to turn annually 500,000 tonnes of waste from the [[City of London]] that would normally go to [[landfill]] into biofuel to be used in the [[British Airways]] fleet,<ref>{{cite news |title= British Airways to buy jet fuel from city waste |date= 16 Feb 2010 |url= https://www.reuters.com/article/us-biofuel-britishairways-idUSTRE61F37520100216 |work= Reuters}}</ref> but filed for bankruptcy in 2015.<ref>{{Cite web|title=AirportWatch {{!}} Solena, the company meant to be producing jet fuel from London waste for BA, goes bankrupt|url=https://www.airportwatch.org.uk/2015/10/solena-the-company-meant-to-be-producing-jet-fuel-from-london-waste-for-ba-goes-bankrupt/|access-date=2021-08-30|website=www.airportwatch.org.uk}}</ref>

By 2015, cultivation of [[fatty acid methyl ester]]s and [[alkenone]]s from the algae, ''Isochrysis'', was under research as a possible jet biofuel [[feedstock]].<ref>{{cite web|author1=Chris Reddy|author2=Greg O'Neil|title=Jet Fuel from Algae? Scientists probe fuel potential in common ocean plant |url= https://www.whoi.edu/oceanus/feature/jet-fuel-from-algae |date=28 January 2015 |work= Oceanus magazine |publisher= [[Woods Hole Oceanographic Institution]]}}</ref>

By 2016, Thomas Brueck of [[Technical University of Munich|Munich TU]] was forecasting that [[algaculture]] could provide 3–5% of jetfueljet fuel needs by 2050.<ref>{{cite news|title=From green slime to jet fuel: algae offers airlines a cleaner future |url= https://reuters.com/article/idUSKCN0Z117F |work= Reuters |date= 15 June 2016}}</ref>

In Fallfall 2016, tothe achieve[[International itsCivil emissionsAviation reductionsOrganization]] goals, theannounced ICAOplans plannedfor multiple measures including the development and deployment of sustainable aviation fuels.<ref name=ICAOdec2018>{{Cite web |url= https://www.icao.int/environmental-protection/Documents/Sustainable%20Aviation%20Fuels%20Guide_100519.pdf |title= Sustainable Aviation Fuels Guide |publisher= ICAO |date= Dec 2018}}</ref>

Dozens of companies received hundreds of millions in [[venture capital]] from 2005 to 2012 to extract fuel oil from algae, some promising competitively -priced fuel by 2012 and a production of {{convert|1|e9USgal|e6m3|abbr=unit}} by 2012-2014.<ref name=Greentech19april2017/> By 2017 most companies had disappeared or changed their [[business plan]]s to focus on other markets.<ref name=Greentech19april2017>{{cite web|last1=Wessof|first1=Eric|title=Hard Lessons From the Great Algae Biofuel Bubble|url=https://www.greentechmedia.com/articles/read/lessons-from-the-great-algae-biofuel-bubble#gs.5jG2khs|publisher=[[Greentech Media]]|date=19 April 2017}}</ref>

In 2019, 0.1% of fuel was SAF:<ref>{{Cite web|last=2021-03-25T14:13:00+00:00|title=How sustainable fuel will help power aviation's green revolution|url=https://www.flightglobal.com/flight-international/how-sustainable-fuel-will-help-power-aviations-green-revolution/143044.article|access-date=2021-03-28|website=Flight Global }}</ref> theThe [[International Air Transport Association]] (IATA) supportssupported the adoption of Sustainable Aviation fuel, aiming in 2019 for a 2% penetrationshare by 2025: {{convert|7|e6m3|e9USgal|abbr=unit}}.<ref name=IATAmay2019>{{cite web |url= https://www.iata.org/contentassets/ed476ad1a80f4ec7949204e0d9e34a7f/fact-sheet-alternative-fuels.pdf |title= Sustainable Aviation Fuels Fact sheet |publisher= IATA |date= May 2019}}</ref><ref name=IEA18mar2019>{{cite news |url= https://www.iea.org/commentaries/are-aviation-biofuels-ready-for-take-off |title= Are aviation biofuels ready for take off? |author= Pharoah Le Feuvre |date= 18 March 2019 |publisher= [[International Energy Agency]]}}</ref>

ThatBy that year, [[Virgin Australia]] had fueled more than 700 flights and flown more than one million kilometers, domestic and international, using [[Gevo Inc|Gevo]]'s alcohol-to-jet fuel.<ref>{{Cite press release |url= https://newsroom.virginaustralia.com/release/virgin-australia%E2%80%99s-sustainable-aviation-fuel-flies-one-million-kilometres|title=Virgin Australia's sustainable aviation fuel flies one million kilometres |publisher= Virgin Australia |date=17 June 2019}}</ref> [[Virgin Atlantic]] was working to regularly use fuel derived from the waste gases of [[steel mill]]s, with [[New Zealand Superannuation Fund#LanzaTech|LanzaTech]].<ref name=AvWeek26apr2019/> [[British Airways]] wanted to convert household waste into jet fuel with [[Fischer–Tropsch process#Velocys|Velocys]].<ref name=AvWeek26apr2019/> [[United Airlines]] committed to {{convert|900|e6USgal|m3|abbr=unit}} of sustainable aviation fuel for 10 years from Fulcrum BioEnergy (of its {{convert|4.1|e9USgal|m3|abbr=unit}} fuel consumption in 2018), after a $30 million investment in 2015.<ref name=AvWeek26apr2019/>

From 2020, [[Qantas]] willplanned startto usinguse a 50/50 blend of [[SG Preston]]'s biofuel on its Los Angeles-Australia flights,. alsoSG providingPreston fuelalso derivedplanned fromto non-foodprovide plant oilsfuel to [[JetBlue Airways]] duringover 10 years.<ref name="AvWeek26apr2019" /> At its sites in [[Singapore]], [[Rotterdam]] and [[Porvoo]], Finland's [[Neste]] is expectingexpected to improve its renewable fuel production capacity from {{convert|2.7 to 3.0|e6t|e9lb|abbr=unit}} a year by 2020, and isto increasingincrease its Singapore capacity by {{convert|1.3|e6t|e9lb|abbr=unit}} to reach {{convert|4.5|e6t|e9lb|abbr=unit}} in 2022 by investing €1.4 billion ($1.6 billion).<ref name=AvWeek26apr2019>{{cite news |url= https://aviationweek.com/commercial-aviation/biofuel-market-nearing-tipping-point |title= Biofuel Market Is Nearing A Tipping Point |date= Apr 26, 2019 |author= Kerry Reals |work= Aviation Week & Space Technology}}</ref>

In early 2021, Boeing's CEO [[Dave Calhoun]] said drop-in [[sustainable aviation fuel]]s are "the only answer between now and 2050" to reduce carbon emissions.<ref name=AvWeek4feb2021>{{cite news |url= https://aviationweek.com/aerospace/manufacturing-supply-chain/boeing-moves-forward-airbus-a321xlr-competitor-plan |title= Boeing Moves Forward With Airbus A321XLR-Competitor Plan |author= Guy Norris |date= February 4, 2021 |work= Aviation Week}}</ref> In May 2021, the [[International Air Transport Association]] (IATA) set a goal for the aviation industry to achieve net-zero carbon emissions by 2050 with SAF as the key component.<ref>{{Cite web |title=Net Zero Roadmaps |url=https://www.iata.org/en/programs/environment/roadmaps/ |access-date=2023-11-17 |website=www.iata.org |language=en}}</ref>

InThe 2022, the [[Inflation Reduction Act]] introduced the Fueling Aviation's Sustainable Transition (FAST) Grant Program. The program provides $244.5 million in grants for SAF-related "production, transportation, blending, and storage."<ref>{{Cite web |date=November 16, 2023 |title=Fueling Aviation's Sustainable Transition (FAST) Grants |url=https://www.faa.gov/general/fueling-aviations-sustainable-transition-fast-grants |access-date=November 16, 2023 |website=Federal Aviation Administration}}</ref> In November, 2022, sustainable aviation fuels were a hot topic at COP26,[[2021 theUnited UN'sNations Climate Change Conference|COP26]].<ref>{{Cite web |last=Nations |first=United |title=COP26: Together for our planet |url=https://www.un.org/en/climatechange/cop26 |access-date=2023-11-17 |website=United Nations |language=en}}</ref>

[[Jet fuel]] is a mixture of various [[hydrocarbon]]s. The range of their sizes ([[molecular weight]]s or carbon numbers)mixture is restricted by theproduct requirements for the product, for example, [[freezing point]] orand [[smoke point]]. Jet fuels are sometimes classified as [[Kerosene jet fuel|kerosene]] or [[naphtha]]-type. Kerosene-type fuels include Jet A, Jet A-1, JP-5 and JP-8. Naphtha-type jet fuels, sometimes referred to as "wide-cut" jet fuel, include Jet B and JP-4.

"Drop-in" biofuels are biofuels that are completely interchangeable with conventional fuels. Deriving "drop-in" jet fuel from bio-based sources is [[ASTM]] approved via two routes. ASTM has also found it safe to blend in 50% SPK into regular jet fuels.<ref>{{Cite web|url=https://www.astm.org/d7566-11.html|title=Standard Specification for Aviation Turbine Fuel Containing Synthesized Hydrocarbons|website=www.astm.org}}</ref><ref name=ASTMsep2011/> Only testsTests have been done so far with blending in synthetic paraffinic kerosene (SPK) in considerably higher concentrations.<ref>{{Cite journal|url=https://repository.tudelft.nl/islandora/object/uuid%3Aca415372-6ac0-4e7a-ab66-6e6dbf564e22|title=Evaluation of safety, performance and emissions of synthetic fuel blends in a Cessna Citation II|first1=T. A.|last1=Snijders|first2=J. A.|last2=Melkert|date=December 22, 2011|journal=Conference ProceeedingsProceedings of the 3AF/AIAA Aircraft Noise and Emissions Reduction Symposium, 25–27 October 2011, Marseille, France|via=repository.tudelft.nl}}</ref>

: Hydroprocessed Esters and Fatty Acids Synthetic Paraffinic Kerosine (HEFA-SPK) is a specific type of hydrotreated [[vegetable oil fuel]].<ref name="Doliente2020" /> {{As of|2020|}} this was the only [[mature technology]].<ref name="IEA18mar2019" /><ref name="Doliente2020" /> HEFA-SPK fuel is considered to be a leading alternative replacement for conventional jet fuel by the [[Civil Aviation Authority (United Kingdom)|CAA]].<ref>{{cite journal |last1=Starck |first1=Laurie |last2=Pidol |first2=Ludivine |last3=Jeuland |first3=Nicolas |last4=Chapus |first4=Thierry |last5=Bogers |first5=Paul |last6=Bauldreay |first6=Joanna |title=Production of Hydroprocessed Esters and Fatty Acids (HEFA) – Optimisation of Process Yield |journal=Oil & Gas Science and Technology – Revue d'IFP Energies nouvelles |date=January 2016 |volume=71 |issue=1 |pages=10 |doi=10.2516/ogst/2014007 |s2cid=45086444 |url=https://ogst.ifpenergiesnouvelles.fr/articles/ogst/pdf/2016/01/ogst120241.pdf |access-date=3 November 2022 |language=en}}</ref> HEFA-SPK was approved by [[Altair Engineering]] for use in 2011.<ref>{{cite web |title=Biofuel Factsheet - Aviation Biofuels |url=https://www.etipbioenergy.eu/images/ETIP_Bioenergy_Factsheet_Aviation_Biofuels.pdf |website=European Technology Innovation Platform - Bioenergy |access-date=3 November 2022 |archive-url=https://web.archive.org/web/20220629124155/https://www.etipbioenergy.eu/images/ETIP_Bioenergy_Factsheet_Aviation_Biofuels.pdf |archive-date=29 June 2022 |language=en |date=2017 |url-status=live}}</ref> HEFA-SPK is produced by the [[deoxygenation]] and hydroprocessing of the [[Raw material|feedstock]] [[fatty acid]]s of [[algae]], [[jatropha]], and [[camelina]].<ref>{{Cite web|url=https://aviationbenefits.org/environmental-efficiency/climate-action/sustainable-aviation-fuel/producing-sustainable-aviation-fuel/|title = Producing sustainable aviation fuel}}</ref>

: This fuel uses oil that is extracted from plant or animal sources such as [[Jatropha oil|''jatropha'']], [[algae]], [[tallows]], waste oils, [[Babassu oil|babassu]], and ''[[Camelina]]'' to produce synthetic paraffinic kerosene (bio-SPK) by cracking and [[hydroprocessing]]. Using [[algae]] to make jet fuel remains an [[emerging technology]]. Companies working on algae jet fuel include [[Solazyme]], Honeywell UOP, Solena, [[Sapphire Energy]], [[Imperium Renewables]], and Aquaflow Bionomic Corporation. Universities working on algae jet fuel are [[Arizona State University]] and [[Cranfield University]]. Major investors for algae -based SPK research are [[Boeing]], [[Honeywell]]/[[UOP LLC|UOP]], [[Air New Zealand]], [[Continental Airlines]], [[Japan Airlines]], and [[General Electric]].{{CnCitation needed|date=February 2023}}

: Another route involves processingProcessing solid [[biomass]] using [[pyrolysis]] tocan produce [[pyrolysis oil|oil]] or [[gasification]] to produce a [[syngas]] that is processed into FT SPK ([[Fischer–Tropsch process|Fischer–Tropsch]] Synthetic Paraffinic Kerosene).{{CnCitation needed|date=February 2023}}

: AlcoholThe alcohol-to-jet (ATJ) pathway takes alcohols such as [[ethanol]] or [[butanol]] and de-oxygenates and processes them into jet fuels.<ref>{{Cite web|url=https://advancedbiofuelsusa.info/tag/atj-spk-alcohol-to-jet-synthetic-paraffinic-kerosene/|title=Advanced BioFuels USA – Truly Sustainable Renewable Future|website=advancedbiofuelsusa.info}}</ref> Companies such as LanzaTech have created ATJ-SPK from {{chem2|CO2}} in [[flue gas]]es.<ref>{{Cite web|url=https://www.lanzatech.com/2018/04/03/jet-fuel-derived-ethanol-now-eligible-commercial-flights/|title=Jet Fuel Derived from Ethanol Now Eligible for Commercial Flights|access-date=2020-12-22|archive-date=2022-01-25|archive-url=https://web.archive.org/web/20220125161620/https://www.lanzatech.com/2018/04/03/jet-fuel-derived-ethanol-now-eligible-commercial-flights/|url-status=dead}}</ref> The ethanol is produced from CO in the flue gases using microbes such as ''[[Clostridium autoethanogenum]]''. In 2016 LanzaTech demonstrated its technology at Pilot scale in NZ –using– using Industrial waste gases from the steel industry as a feedstock for its microbial fermentation.<ref>Voegele, E. November 2009. "Waste to ethanol projects move forward", Ethanol Producer Magazine</ref><ref>{{Cite web|url=https://www.triplepundit.com/story/2013/interview-lanzatech-ceo-jennifer-holmgren/52196|title=Interview: LanzaTech CEO Jennifer Holmgren|website=www.triplepundit.com}}</ref><ref>{{Cite journal|url= |title=Genome editing of Clostridium autoethanogenum using CRISPR/Cas9|first1=Shilpa|last1=Nagaraju|first2=Naomi Kathleen|last2=Davies|first3=David Jeffrey Fraser|last3=Walker|first4=Michael|last4=Köpke|first5=Séan Dennis|last5=Simpson|date=October 18, 2016|journal=Biotechnology for Biofuels|volume=9|issue=1|pages=219|doi=10.1186/s13068-016-0638-3|pmid=27777621|pmc=5069954 |doi-access=free |bibcode=2016BB......9..219N }}</ref> [[Gevo]] developed technology to retrofit existing [[ethanol]] plants to produce [[isobutanol]].<ref>{{Cite web |url=https://gevo.com/wp-content/uploads/2020/05/Gevo-Whitepaper-Sustainable-Aviation-Fuel.pdf |title=Archived copy |access-date=2021-11-23 |archive-date=2021-06-23 |archive-url=https://web.archive.org/web/20210623212715/https://gevo.com/wp-content/uploads/2020/05/Gevo-Whitepaper-Sustainable-Aviation-Fuel.pdf |url-status=dead }}</ref> Alcohol-to-Jet Synthetic Paraffinic Kerosene (ATJ-SPK) is a proven pathway to deliver a bio-based, low-carbon option to travelersfuel.{{CnCitation needed|date=February 2023}}

=== Future production routes ===

Systems that use [[synthetic biology]] to create hydro-carbons are under development.:

* Alder Fuels is proposing a method to convert [[lignocellulosic biomass]] (a common type of waste from forestry and agriculture) into a hydrocarbon-rich "greencrude" via [[pyrolysis]] (see: [[pyrolysis oil]]). Greencrude can be turned into fuel in refineries like crude oil.<ref>{{Cite news |date=August 17, 2022 |title=Ways to make aviation fuel green |newspaper=The Economist |url=https://www.economist.com/science-and-technology/2022/08/17/ways-to-make-aviation-fuel-green |access-date=2023-02-23 |issn=0013-0613}}</ref>

=== Technical challenges ===

TheIn 2019 the [[International Energy Agency]] forecast SAF production should grow from 18 to 75 billion litres between 2025 and 2040, representing a 5% to 19% share of aviation fuel.<ref gettingname=IEA18mar2019/> fromBy 5%2019, fossil jet fuel production cost was $0.3-0.6 per L given a $50–100 crude [[oil barrel]], while aviation biofuel production cost was $0.7-1.6, needing a $110–260 crude oil barrel to 19%[[break-even]].<ref name=IEA18mar2019/>

{{As of|2020|}} aviation biofuel iswas more expensive than fossil jet kerosene,<ref name=IU4dec2020/> considering [[aviation taxation and subsidies]] at that time.<ref>{{Cite web |title= Sustainable Aviation Fuel: Review of Technical Pathways |url= https://www.energy.gov/sites/prod/files/2020/09/f78/beto-sust-aviation-fuel-sep-2020.pdf |date= Sep 2020 |publisher= [[United States Department of Energy]]}}</ref>

As of a 2021 techno-economic analysis, VFA-SAF can have a break-even cost ofwas ${{Convert|2.50|$/gal|$/gallonl|abbr=on}}.<ref name="auto"/> This number was generated considering the government credits and incentives at the time, such as [[LCFS|California's LCFS]] (Low Carbon Fuel Standard) credits and the US Environmental Protection Agency (EPA) [[Renewable Fuel Standard (United States)|Renewable Fuel Standard]] incentives.

[[Sustainable biofuel]]s do not use [[food crop]]s, prime [[agricultural land]] or fresh water. '''Sustainable aviation fuel''' (SAF) is certified by a third-party such as the [[Sustainable biofuel#Roundtable on Sustainable Biomaterials|Roundtable For Sustainable Biofuels]].<ref>{{cite news |url= http://aviationweek.com/commercial-aviation/glacial-pace-advancements-biofuel-threatens-emissions-targets |title= Glacial Pace Of Advancements In Biofuel Threatens Emissions Targets |date= Oct 10, 2017 |author= Kerry Reals |work=[[Aviation Week & Space Technology]]}}</ref>

A sustainable aviation fuel (SAF) sustainability certification verifiesensures that the product has satisfiedsatisfies criteria focused on environmental, social, and economic "[[triple-bottom-line]]" considerations. Under many emission regulation schemes, such as the [[European Union Emissions Trading Scheme]] (EUTS), a certified SAF product may be exempted from carbon compliance liability costs.<ref>{{cite web|url=http://ec.europa.eu/energy/renewables/biofuels/sustainability_schemes_en.htm|title=Sustainability schemes for biofuels|work=European Commission/Energy/Renewable energy/Biofuels|access-date=1 April 2012}}</ref> This marginally improves SAF's economic competitiveness overversus fossil-based fuel. However, commercialisation and regulatory hurdles remain to achieve price parity and to enable widespread uptake.<ref>{{cite web|url=http://www.qantas.com.au/travel/airlines/sustainable-aviation-fuel/global/en#jump4 |title=Sustainable Aviation Fuel |publisher=Qantas |access-date=2013-10-24}}</ref>

The first reputable body to launch a sustainable biofuel certification system was the European-based Roundtable on Sustainable Biomaterials (RSB) NGO.<ref>{{cite web |url=http://rsb.epfl.ch/files/content/sites/rsb2/files/Biofuels/Documents%20and%20Resources/11-10-07_RSB_Fact_Sheet_EN.pdf |title=RSB Roundtable on Sustainable Biomaterials &#124; Roundtable on Sustainable Biomaterials |website=Rsb.epfl.ch |date=2013-10-17 |access-date=2013-10-24 |archive-date=2011-12-22 |archive-url=https://web.archive.org/web/20111222050201/http://rsb.epfl.ch/files/content/sites/rsb2/files/Biofuels/Documents%20and%20Resources/11-10-07_RSB_Fact_Sheet_EN.pdf |url-status=dead }}</ref> Leading airlines and other signatories to the Sustainable Aviation Fuel Users Group (SAFUG) pledged to support RSB as thetheir preferred certification provider.<ref>{{cite web|url=http://www.safug.org/information/pledge/ |access-date=March 29, 2012 |url-status=dead |archive-url=https://web.archive.org/web/20120425051329/http://www.safug.org/information/pledge/ |archive-date=April 25, 2012 |title=Our Commitment to Sustainable Options}}</ref><ref>{{cite web|url=http://www.safug.org/ |title=Sustainable Aviation Fuel Users Group – SAFUG |website=Safug.org |access-date=2013-10-24}}</ref>

Some SAF pathways have also procured [[Renewable Identification Number|RIN]] pathways under the United States's [[Renewable Fuel Standard (United States)|renewable fuel standard]] which can serve as an implicit certification if the RIN is a [[Renewable Identification Number|Q-RIN]].

{{NoMore footnotes needed|section|date=February 2023}}

: Greenhouse gas emissions from sustainable fuels must be lower than those from the fuels they replace: at least 50% for production built prior tobefore 5 October 2015, 60% after that date and 65% after 2021. Raw materials cannot be sourced from land with high biodiversity or high carbon stocks (i.e. primary and protected forests, biodiversity-rich grasslands, wetlands and [[peatland]]s). Other sustainability issues are set out in the Governance Regulation and may be covered on a voluntary basisvoluntarily.

As [[emissions trading schemes]] and other carbon compliance regimes emerge, certain biofuels are likely to be exempted ("zero -rated") by governments from carbon compliance due to their closed-loop nature, if they can provedemonstrate their wider sustainabilityappropriate credentials. For example, in the EUTS, SAFUG's proposal was accepted<ref>{{cite web |title=Revision of the EU Energy Tax Directive - technical press briefing |url=http://ec.europa.eu/taxation_customs/resources/documents/taxation/review_of_regulation_en.pdf |access-date=2013-10-24 |website=Ec.europa.eu}}</ref> that only fuels certified as sustainable by the RSB or similar body would be zero -rated.<ref>{{cite web|url=http://www.safug.org/assets/docs/SAFUG_Brochure.pdf |title=Sustainable Aviation Fuel Users Group : European Section |website=Safug.org |access-date=2013-10-24}}</ref> SAFUG was formed by a group of interested airlines in 2008 under the auspices of [[Boeing Commercial Airplanes]]. Member airlines representrepresented more than 15% of the industry, and signed a pledge to work towards SAF.<ref>{{cite web|url=http://www.boeing.com/newairplane/environment/#/SustainableAviationBiofuel/UsersGroup |title=Environment and Biofuels &#124; Boeing Commercial Airplanes |website=Boeing.com |access-date=2013-10-24}}</ref><ref>{{cite web|url=http://www.safug.org/safug-pledge/ |title= SAFUG Pledge; Boeing Commercial Airplanes |website=Safug.org |access-date=2015-07-10}}</ref>

In addition to SAF certification, the integrity of aviation biofuel producers and their productproducts cancould be assessed by means such as [[Richard Branson]]'s Carbon War Room,<ref>{{cite web |url=http://www.carbonwarroom.com/sectors/transport/aviation/operation-renewablejetfuels#mission |title=Renewable Jet Fuels |publisher=Carbon War Room |access-date=2013-10-24 |archive-date=2013-10-30 |archive-url=https://web.archive.org/web/20131030013036/http://www.carbonwarroom.com/sectors/transport/aviation/operation-renewablejetfuels#mission |url-status=dead }}</ref> or the Renewable Jet Fuels initiative.<ref>{{cite web |url=http://renewablejetfuels.org/ |title=Welcome |publisher=Renewable Jet Fuels |access-date=2013-10-24 |archive-date=2013-10-29 |archive-url=https://web.archive.org/web/20131029205231/http://renewablejetfuels.org/ |url-status=dead }}</ref> The latter works with companies such as LanzaTech, SG Biofuels, AltAir, Solazyme, and Sapphire.<ref>{{cite web|url=http://www.sustainablesky.com |title=Sustainable Sky Institute |publisher=Sustainable Sky Institute |access-date=2016-04-26}}</ref>{{vnverify source|date=February 2023}}

Along with her co-authors, [[Candelaria Bergero]] of the [[University of California]]'s [[Earth System Science]] Department stated that "main challenges to scaling up such sustainable fuel production include technology costs and process efficiencies", and widespread production would undermine [[food security]] and [[land use]].<ref>{{cite journal |last1=Bergero |first1=Candelaria |display-authors= etal |title=Pathways to net-zero emissions from aviation |journal= [[Nature Sustainability]] |date=30 January 2023 |volume=6 |issue=4 |pages=404–414 |doi=10.1038/s41893-022-01046-9 |s2cid=256449498 |doi-access=free |bibcode=2023NatSu...6..404B |url=https://www.researchsquare.com/article/rs-1871023/latest.pdf }}</ref>

* {{cite web |url= https://www.sustainablesky.com/ |title= Sustainable Sky Institute |quote= non-profit think tank/do tank focussedfocused on [...] the market transformation of the world's air transport system towards a [...] sustainable long-term future}}