Aviation biofuel: Difference between revisions

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> 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 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. Alder Renewables, BioVeritas, and ChainCraft are a few organizations committed to this.