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Aviation biofuel
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><h2 id="environmental-impact">Environmental impact</h2> <p class="note">Further information: <a href="/facts/Environmental_impact_of_aviation/YylDhhjp">Environmental impact of aviation</a> and <a href="/facts/Biofuel/RWu7b6Y3">Biofuel § Greenhouse gas emissions</a></p> <p>Plants absorb <a href="/facts/Carbon_Dioxide/xGzpppEp">carbon dioxide</a> as they grow, therefore plant-based biofuels emit only the same amount of <a href="/facts/Greenhouse_gas/HXaHqrT8">greenhouse gases</a> as they had previously absorbed. Biofuel production, processing, and transport, however, emit greenhouse gases, reducing the emissions savings.<a class="footnote-ref" id="fnref:10" href="#fn:10"><sup>10</sup></a> Biofuels with the most emission savings are those derived from photosynthetic algae (98% savings) although the technology is not developed, and those from <a href="/facts/Second-generation_biofuels/ujFW2nIk">non-food crops and forest residues</a> (91–95% savings).<a class="footnote-ref" id="fnref:11" href="#fn:11"><sup>11</sup></a> </p><p><a href="/facts/Jatropha_oil/mEWHAABd">Jatropha oil</a>, a non-food oil used as a biofuel, lowers CO2 emissions by 50–80% compared to Jet-A1, a <a href="/facts/Kerosene/DoHPYXKp">kerosene</a>-based fuel.<a class="footnote-ref" id="fnref:12" href="#fn:12"><sup>12</sup></a> Jatropha, used for <a href="/facts/Biodiesel/M6FkfJXH">biodiesel</a>, can thrive on <a href="/facts/Marginal_land/XXbb8G9L">marginal land</a> where most plants produce low <a href="/facts/Crop_yield/hmE59fhk">yields</a>.<a class="footnote-ref" id="fnref:13" href="#fn:13"><sup>13</sup></a><a class="footnote-ref" id="fnref:14" href="#fn:14"><sup>14</sup></a> A <a href="/facts/Life_cycle_assessment/vGKCvfYf">life cycle assessment</a> 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.<a class="footnote-ref" id="fnref:15" href="#fn:15"><sup>15</sup></a> </p><p><a href="/facts/Palm_oil/n8zHXqoG">Palm oil</a> cultivation is constrained by scarce land resources and its expansion to forestland causes <a href="/facts/Biodiversity_loss/p7xI1P0G">biodiversity loss</a>, along with direct and indirect emissions due to <a href="/facts/Land-use_change/W6dVvXjT">land-use change</a>.<a class="footnote-ref" id="fnref:16" href="#fn:16"><sup>16</sup></a> <a href="/facts/Neste_Corporation/1EGlFWMD">Neste Corporation</a>'s renewable products include a refining <a href="/facts/Byproduct/qDosnqoD">residue</a> of food-grade palm oil, the oily waste <a href="/facts/Resource_recovery/RSI2uWfu">skimmed</a> from the palm oil mill's <a href="/facts/Wastewater/g6Bn8xvT">wastewater</a>. Other Neste sources are <a href="/facts/Used_cooking_oil/tmuALVJX">used cooking oil</a> from <a href="/facts/Deep_fryer/oQBNJJ4L">deep fryers</a> and animal fats.<a class="footnote-ref" id="fnref:17" href="#fn:17"><sup>17</sup></a> <a href="https://www.neste.com/en-us/products-and-innovation/sustainable-aviation/sustainable-aviation-fuel">Neste's sustainable aviation fuel</a> is used by <a href="/facts/Lufthansa/TUsmAkwr">Lufthansa</a>;<a class="footnote-ref" id="fnref:18" href="#fn:18"><sup>18</sup></a> <a href="/facts/Air_France/YG3cSyM7">Air France</a> and <a href="/facts/KLM/MqV26wwo">KLM</a> announced 2030 SAF targets in 2022<a class="footnote-ref" id="fnref:19" href="#fn:19"><sup>19</sup></a> including multi-year purchase contracts totaling over 2.4 million tonnes of SAF from Neste, <a href="/facts/TotalEnergies/4KJe17r6">TotalEnergies</a>, and DG Fuels.<a class="footnote-ref" id="fnref:20" href="#fn:20"><sup>20</sup></a> </p><p>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.<a class="footnote-ref" id="fnref:21" href="#fn:21"><sup>21</sup></a> This lessens the need to grow crops specifically for fuel, which in itself is energy intensive and increases CO2 emissions throughout its life cycle. Wet waste feedstocks for SAF divert waste from landfills. Diversion has the potential to eliminate 17% of US methane emissions across all sectors. VFA-SAF's carbon footprint is 165% lower than fossil aviation fuel.<a class="footnote-ref" id="fnref:22" href="#fn:22"><sup>22</sup></a> This technology is in its infancy; although start-ups are working to make this a viable solution. Alder Renewables, BioVeritas, and ChainCraft are a few organizations committed to this. </p><p>NASA has determined that 50% aviation biofuel mixture can cut <a href="/facts/Particulate_emissions/RleGr5E6">particulate emissions</a> caused by air traffic by 50–70%.<a class="footnote-ref" id="fnref:23" href="#fn:23"><sup>23</sup></a> Biofuels do not contain sulfur compounds and thus do not emit <a href="/facts/Sulfur_dioxide/jDK1fIDs">sulfur dioxide</a>. </p> <h2 id="history">History</h2> <p class="note">See also: <a href="/facts/Aviation_biofuel_demonstrations/vzcM9NPh">Aviation biofuel demonstrations</a></p> <p>The first flight using blended <a href="/facts/Biofuel/RWu7b6Y3">biofuel</a> took place in 2008.<a class="footnote-ref" id="fnref:24" href="#fn:24"><sup>24</sup></a> <a href="/facts/Virgin_Atlantic/nxvBS6gU">Virgin Atlantic</a> used it fly a commercial airliner, using feedstocks such as <a href="/facts/Algae/U1ftVKU3">algae</a>.<a class="footnote-ref" id="fnref:25" href="#fn:25"><sup>25</sup></a> Airlines representing more than 15% of the industry formed the Sustainable Aviation Fuel Users Group, with support from NGOs such as <a href="/facts/Natural_Resources_Defense_Council/1Cb7xy6K">Natural Resources Defense Council</a> and <a href="/facts/Sustainable_biofuel/TlQHrWrm">The Roundtable For Sustainable Biofuels</a> by 2008. They pledged to develop <a href="/facts/Sustainable_biofuels/TlQHrWrm">sustainable biofuels</a> for aviation.<a class="footnote-ref" id="fnref:26" href="#fn:26"><sup>26</sup></a> That year, Boeing was co-chair of the <a href="/facts/Algal_Biomass_Organization/A0SBG0RL">Algal Biomass Organization</a>, joined by air carriers and biofuel technology developer <a href="/facts/UOP_LLC/5tc4x9AT">UOP LLC</a> (Honeywell).<a class="footnote-ref" id="fnref:27" href="#fn:27"><sup>27</sup></a> </p><p>In 2009, the IATA committed to achieving <a href="/facts/Carbon-neutral/llsAknfI">carbon-neutral</a> growth by 2020, and to halve carbon emissions by 2050.<a class="footnote-ref" id="fnref:28" href="#fn:28"><sup>28</sup></a> </p><p>In 2010, Boeing announced a target 1% of global aviation fuels by 2015.<a class="footnote-ref" id="fnref:29" href="#fn:29"><sup>29</sup></a> </p> <p>By June 2011, the revised <i>Specification for Aviation Turbine Fuel Containing Synthesized Hydrocarbons</i> (<a href="/facts/ASTM/xzdCexYJ">ASTM</a> D7566) allowed commercial airlines to blend up to 50% biofuels with conventional jet fuel.<a class="footnote-ref" id="fnref:30" href="#fn:30"><sup>30</sup></a> The safety and performance of jet fuel used in passenger flights is certified by <a href="/facts/ASTM_International/xzdCexYJ">ASTM International</a>.<a class="footnote-ref" id="fnref:31" href="#fn:31"><sup>31</sup></a> Biofuels were approved for commercial use after a multi-year technical review from <a href="/facts/Aerospace_manufacturer/fdGwdY85">aircraft makers</a>, <a href="/facts/List_of_turbofan_manufacturers/tE5v2TLw">engine manufacturers</a> and <a href="/facts/Oil_companies/3sPDxcPx">oil companies</a>.<a class="footnote-ref" id="fnref:32" href="#fn:32"><sup>32</sup></a> Thereafter some airlines experimented with biofuels on commercial flights.<a class="footnote-ref" id="fnref:33" href="#fn:33"><sup>33</sup></a> As of July 2020, seven annexes to D7566 were published, including various biofuel types:<a class="footnote-ref" id="fnref:34" href="#fn:34"><sup>34</sup></a> </p> <ul><li>Fischer-Tropsch Synthetic Paraffinic Kerosene (FT-SPK, 2009)</li> <li>Hydroprocessed Esters and Fatty Acids Synthetic Paraffinic Kerosene (HEFA-SPK, 2011)</li> <li>usHydroprocessed Fermented Sugars to Synthetic Isoparaffins (HFS-SIP, 2014)</li> <li>Fischer-Tropsch Synthetic Paraffinic Kerosene with Aromatics (FT-SPK/A, 2015)</li> <li>Alcohol to Jet Synthetic Paraffinic Kerosene (ATJ-SPK, 2016)</li> <li>Catalytic Hydrothermolysis Synthesized Kerosene (CH-SK, or CHJ; 2020).</li></ul> <p>In December 2011, the <a href="/facts/FAA/BfmGoJhe">FAA</a> awarded US$7.7 million to eight companies to develop <a href="/facts/Substitute_good/oK7UJNjw">drop-in</a> sustainable fuels, especially from <a href="/facts/Alcohol_(chemistry)/Y0SCTDkh">alcohols</a>, sugars, <a href="/facts/Biomass/4VHjaya3">biomass</a>, and <a href="/facts/Organic_matter/t17tVCvk">organic matter</a> such as <a href="/facts/Pyrolysis_oil/JqQnKf70">pyrolysis oils</a>, within its CAAFI and CLEEN programs.<a class="footnote-ref" id="fnref:35" href="#fn:35"><sup>35</sup></a> </p><p>Biofuel provider Solena filed for bankruptcy in 2015.<a class="footnote-ref" id="fnref:36" href="#fn:36"><sup>36</sup></a> </p><p>By 2015, cultivation of <a href="/facts/Fatty_acid_methyl_ester/q3fUpu56">fatty acid methyl esters</a> and <a href="/facts/Alkenone/gAflh5z4">alkenones</a> from the algae, <i>Isochrysis</i>, was under research.<a class="footnote-ref" id="fnref:37" href="#fn:37"><sup>37</sup></a> </p><p>By 2016, Thomas Brueck of <a href="/facts/Technical_University_of_Munich/14UXILEo">Munich TU</a> was forecasting that <a href="/facts/Algaculture/pWK5XI1f">algaculture</a> could provide 3–5% of jet fuel needs by 2050.<a class="footnote-ref" id="fnref:38" href="#fn:38"><sup>38</sup></a> </p><p>In fall 2016, the <a href="/facts/International_Civil_Aviation_Organization/TzrL1mLr">International Civil Aviation Organization</a> announced plans for multiple measures including the development and deployment of sustainable aviation fuels.<a class="footnote-ref" id="fnref:39" href="#fn:39"><sup>39</sup></a> </p><p>Dozens of companies received hundreds of millions in <a href="/facts/Venture_capital/yeH3m7zo">venture capital</a> from 2005 to 2012 to extract fuel oil from algae, some promising competitively-priced fuel by 2012 and production of 1 billion US gal (3.8 million m3) by 2012-2014.<a class="footnote-ref" id="fnref:40" href="#fn:40"><sup>40</sup></a> By 2017 most companies had disappeared or changed their <a href="/facts/Business_plan/PmJfIjr3">business plans</a> to focus on other markets.<a class="footnote-ref" id="fnref:41" href="#fn:41"><sup>41</sup></a> </p><p>In 2019, 0.1% of fuel was SAF:<a class="footnote-ref" id="fnref:42" href="#fn:42"><sup>42</sup></a> The <a href="/facts/International_Air_Transport_Association/nes88P7H">International Air Transport Association</a> (IATA) supported the adoption of Sustainable Aviation fuel, aiming in 2019 for 2% share by 2025: 7 million m3 (1.8 billion US gal).<a class="footnote-ref" id="fnref:43" href="#fn:43"><sup>43</sup></a><a class="footnote-ref" id="fnref:44" href="#fn:44"><sup>44</sup></a> </p> <p>In early 2021, Boeing's CEO <a href="/facts/Dave_Calhoun/51FyPPf5">Dave Calhoun</a> said drop-in <a href="/facts/Sustainable_aviation_fuel/Y3QzuIop">sustainable aviation fuels</a> are "the only answer between now and 2050" to reduce carbon emissions.<a class="footnote-ref" id="fnref:45" href="#fn:45"><sup>45</sup></a> In May 2021, the <a href="/facts/International_Air_Transport_Association/nes88P7H">International Air Transport Association</a> (IATA) set a goal for the aviation industry to achieve net-zero carbon emissions by 2050 with SAF as the key component.<a class="footnote-ref" id="fnref:46" href="#fn:46"><sup>46</sup></a> </p><p>The 2022 <a href="/facts/Inflation_Reduction_Act/8Cdfo0tk">Inflation Reduction Act</a> 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."<a class="footnote-ref" id="fnref:47" href="#fn:47"><sup>47</sup></a> In November, 2022, sustainable aviation fuels were a topic at <a href="/facts/2021_United_Nations_Climate_Change_Conference/JARSYWLa">COP26</a>.<a class="footnote-ref" id="fnref:48" href="#fn:48"><sup>48</sup></a> </p><p>As of 2023, 90% of biofuel was made from oilseed and sugarcane which are grown for this purpose only.<a class="footnote-ref" id="fnref:49" href="#fn:49"><sup>49</sup></a> </p> <h2 id="production">Production</h2> <p><a href="/facts/Jet_fuel/4CDswF3t">Jet fuel</a> is a mixture of various <a href="/facts/Hydrocarbon/Dcg95Ju5">hydrocarbons</a>. The mixture is restricted by product requirements, for example, <a href="/facts/Freezing_point/MY0w0h0k">freezing point</a> and <a href="/facts/Smoke_point/5akKcjW8">smoke point</a>. Jet fuels are sometimes classified as <a href="/facts/Kerosene_jet_fuel/4CDswF3t">kerosene</a> or <a href="/facts/Naphtha/DpzLNMey">naphtha</a>-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. </p><p>"Drop-in" biofuels are biofuels that are interchangeable with conventional fuels. Deriving "drop-in" jet fuel from bio-based sources is <a href="/facts/ASTM/xzdCexYJ">ASTM</a> approved via two routes. ASTM has found it safe to blend in 50% SPK into regular jet fuels.<a class="footnote-ref" id="fnref:50" href="#fn:50"><sup>50</sup></a><a class="footnote-ref" id="fnref:51" href="#fn:51"><sup>51</sup></a> Tests have been done with blending synthetic paraffinic kerosene (SPK) in considerably higher concentrations.<a class="footnote-ref" id="fnref:52" href="#fn:52"><sup>52</sup></a> </p> HEFA-SPK Hydroprocessed Esters and Fatty Acids Synthetic Paraffinic Kerosine (HEFA-SPK) is a specific type of hydrotreated <a href="/facts/Vegetable_oil_fuel/tmuALVJX">vegetable oil fuel</a>.<a class="footnote-ref" id="fnref:53" href="#fn:53"><sup>53</sup></a> As of 2020 this was the only <a href="/facts/Mature_technology/26qVA5Ky">mature technology</a><a class="footnote-ref" id="fnref:54" href="#fn:54"><sup>54</sup></a><a class="footnote-ref" id="fnref:55" href="#fn:55"><sup>55</sup></a><a class="footnote-ref" id="fnref:56" href="#fn:56"><sup>56</sup></a> (but by 2024 FT-SPK was commercialized as well<a class="footnote-ref" id="fnref:57" href="#fn:57"><sup>57</sup></a>). HEFA-SPK was approved by <a href="/facts/Altair_Engineering/uDLdNeox">Altair Engineering</a> for use in 2011.<a class="footnote-ref" id="fnref:58" href="#fn:58"><sup>58</sup></a> HEFA-SPK is produced by the <a href="/facts/Deoxygenation/je4B9r5N">deoxygenation</a> and hydroprocessing of the <a href="/facts/Raw_material/cthCpclF">feedstock</a> <a href="/facts/Fatty_acid/JGg3erIu">fatty acids</a> of <a href="/facts/Algae/U1ftVKU3">algae</a>, <a href="/facts/Jatropha/j5dezrBB">jatropha</a>, and <a href="/facts/Camelina/XxgywCqU">camelina</a>.<a class="footnote-ref" id="fnref:59" href="#fn:59"><sup>59</sup></a> Bio-SPK This fuel uses oil extracted from plant or animal sources such as <a href="/facts/Jatropha_oil/mEWHAABd"><i>jatropha</i></a>, <a href="/facts/Algae/U1ftVKU3">algae</a>, <a href="/facts/Tallows/JNWsebPc">tallows</a>, waste oils, <a href="/facts/Babassu_oil/lFDndMkM">babassu</a>, and <i><a href="/facts/Camelina/XxgywCqU">Camelina</a></i> to produce synthetic paraffinic kerosene (bio-SPK) by cracking and <a href="/facts/Hydroprocessing/XHQMvI7w">hydroprocessing</a>. Using <a href="/facts/Algae/U1ftVKU3">algae</a> to make jet fuel remains an <a href="/facts/Emerging_technology/9Aoq6j9S">emerging technology</a>. Companies working on algae jet fuel include <a href="/facts/Solazyme/wV9770be">Solazyme</a>, Honeywell UOP, Solena, <a href="/facts/Sapphire_Energy/0q7nYzgP">Sapphire Energy</a>, <a href="/facts/Imperium_Renewables/J0KojbsW">Imperium Renewables</a>, and Aquaflow Bionomic Corporation. Universities working on algae jet fuel are <a href="/facts/Arizona_State_University/e4lLNfmP">Arizona State University</a> and <a href="/facts/Cranfield_University/Q6rsfoad">Cranfield University</a>. Major investors for algae-based SPK research are <a href="/facts/Boeing/tF5sMe9F">Boeing</a>, <a href="/facts/Honeywell/qjkujlwJ">Honeywell</a>/<a href="/facts/UOP_LLC/5tc4x9AT">UOP</a>, <a href="/facts/Air_New_Zealand/myFfWE64">Air New Zealand</a>, <a href="/facts/Continental_Airlines/dQG1kXEm">Continental Airlines</a>, <a href="/facts/Japan_Airlines/1rghNtqB">Japan Airlines</a>, and <a href="/facts/General_Electric/bBm5CzVY">General Electric</a>. FT-SPK Processing solid <a href="/facts/Biomass/4VHjaya3">biomass</a> using <a href="/facts/Pyrolysis/h1cEegI7">pyrolysis</a> can produce <a href="/facts/Pyrolysis_oil/JqQnKf70">oil</a> or <a href="/facts/Gasification/kN2Ng4hL">gasification</a> to produce a <a href="/facts/Syngas/VfslxkIN">syngas</a> that is processed into FT SPK (<a href="/facts/Fischer%25E2%2580%2593Tropsch_process/qx8noLlC">Fischer–Tropsch</a> Synthetic Paraffinic Kerosene). ATJ-SPK The alcohol-to-jet (ATJ) pathway takes alcohols such as <a href="/facts/Ethanol/3lCLfBSP">ethanol</a> or <a href="/facts/Butanol/KkvSRuCb">butanol</a> and de-oxygenates and processes them into jet fuels.<a class="footnote-ref" id="fnref:60" href="#fn:60"><sup>60</sup></a> Companies such as LanzaTech have created ATJ-SPK from CO2 in <a href="/facts/Flue_gas/ETBGr9II">flue gases</a>.<a class="footnote-ref" id="fnref:61" href="#fn:61"><sup>61</sup></a> The ethanol is produced from CO in the flue gases using microbes such as <i><a href="/facts/Clostridium_autoethanogenum/0xpYdYga">Clostridium autoethanogenum</a></i>. In 2016 LanzaTech demonstrated its technology at Pilot scale in NZ – using Industrial waste gases from the steel industry as a feedstock.<a class="footnote-ref" id="fnref:62" href="#fn:62"><sup>62</sup></a><a class="footnote-ref" id="fnref:63" href="#fn:63"><sup>63</sup></a><a class="footnote-ref" id="fnref:64" href="#fn:64"><sup>64</sup></a> <a href="/facts/Gevo/IfexDNDr">Gevo</a> developed technology to retrofit existing <a href="/facts/Ethanol/3lCLfBSP">ethanol</a> plants to produce <a href="/facts/Isobutanol/JNB4Hh9W">isobutanol</a>.<a class="footnote-ref" id="fnref:65" href="#fn:65"><sup>65</sup></a> Alcohol-to-Jet Synthetic Paraffinic Kerosene (ATJ-SPK) is a proven pathway to deliver bio-based, low-carbon fuel. <h3>Future production routes</h3> <p>Systems that use <a href="/facts/Synthetic_biology/rHSNe8j3">synthetic biology</a> to create hydro-carbons are under development: </p> <ul><li>The SUN-to-LIQUID project is examining Fischer-Tropsch hydro-carbon fuels (solar kerosine) through the use of a <a href="/facts/Chemical_reactor/asqApwa4">solar reactor</a>.<a class="footnote-ref" id="fnref:66" href="#fn:66"><sup>66</sup></a><a class="footnote-ref" id="fnref:67" href="#fn:67"><sup>67</sup></a><a class="footnote-ref" id="fnref:68" href="#fn:68"><sup>68</sup></a></li> <li>Alder Fuels is proposing to convert <a href="/facts/Lignocellulosic_biomass/b9EkMneQ">lignocellulosic biomass</a> (a common type of waste from forestry and agriculture) into a hydrocarbon-rich "greencrude" via <a href="/facts/Pyrolysis/h1cEegI7">pyrolysis</a> (see: <a href="/facts/Pyrolysis_oil/JqQnKf70">pyrolysis oil</a>). Greencrude can be turned into fuel in refineries like crude oil.<a class="footnote-ref" id="fnref:69" href="#fn:69"><sup>69</sup></a></li> <li>Universal Fuel Technologies is marketing its Flexiforming technology that can use different feedstocks and even the byproducts from existing renewable fuel manufacturing processes to produce SAF.<a class="footnote-ref" id="fnref:70" href="#fn:70"><sup>70</sup></a></li> <li>Arcadia eFuels is constructing a plant that will use renewable electricity to perform electrolysis of water to produce green hydrogen coupled with CO2 capture to produce syngas and use <a href="/facts/Power-to-X/nI7GDNvD">Power-to-X</a> gas to liquid processes to produce SAF.<a class="footnote-ref" id="fnref:71" href="#fn:71"><sup>71</sup></a> The plant at the port of Vordingborg, Denmark is expected to begin production in 2028.<a class="footnote-ref" id="fnref:72" href="#fn:72"><sup>72</sup></a></li></ul> <h3>Piston engines</h3> <p>Small piston engines can be modified to burn <a href="/facts/Ethanol/3lCLfBSP">ethanol</a>.<a class="footnote-ref" id="fnref:73" href="#fn:73"><sup>73</sup></a> <a href="/facts/Swift_Fuel/jno8BhvW">Swift Fuel</a>, a biofuel alternative to <a href="/facts/Avgas/jno8BhvW">avgas</a>, was approved as a test fuel by <a href="/facts/ASTM_International/xzdCexYJ">ASTM International</a> in December 2009.<a class="footnote-ref" id="fnref:74" href="#fn:74"><sup>74</sup></a><a class="footnote-ref" id="fnref:75" href="#fn:75"><sup>75</sup></a> </p> <h3>Technical challenges</h3> <p><a href="/facts/Nitrile/Gz7RCnC6">Nitrile</a>-based rubber materials expand in the presence of aromatic compounds found in conventional petroleum fuel. Pure biofuels without petroleum and paraffin-based additives may cause rubber seals and hoses to shrink.<a class="footnote-ref" id="fnref:76" href="#fn:76"><sup>76</sup></a> Synthetic rubber substitutes that are not adversely affected by biofuels, such as <a href="/facts/Viton/JzFbjeby">Viton</a>, for seals and hoses are available.<a class="footnote-ref" id="fnref:77" href="#fn:77"><sup>77</sup></a> </p><p>The <a href="/facts/United_States_Air_Force/7MxWBYlc">United States Air Force</a> found harmful bacteria and fungi in their biofueled aircraft, and use <a href="/facts/Pasteurization/LnpM2tK1">pasteurization</a> to disinfect them.<a class="footnote-ref" id="fnref:78" href="#fn:78"><sup>78</sup></a> </p> <h4>Aromatics and cycloalkanes</h4> <p>As of May 2025 SAF is generally required to be blended with fossil fuel—because jet fuel needs <a href="/facts/Cycloalkanes/8dQAoD1N">cycloalkanes</a> and <a href="/facts/Aromatic_compound/3EXq8Tgf">aromatics</a>, which are generally deficient in SAF; as well as the more prevalent in SAF <a href="/facts/Alkane/Qam7Hvmf">n-alkanes</a> and isoalkanes.<a class="footnote-ref" id="fnref:79" href="#fn:79"><sup>79</sup></a> </p> <h2 id="economics">Economics</h2> <p>In 2019 the <a href="/facts/International_Energy_Agency/HErEraSy">International Energy Agency</a> forecast SAF production should grow from 18 to 75 billion litres between 2025 and 2040, representing a 5% to 19% share of aviation fuel.<a class="footnote-ref" id="fnref:80" href="#fn:80"><sup>80</sup></a> By 2019, fossil jet fuel production cost was $0.3-0.6 per L given a $50–100 crude <a href="/facts/Oil_barrel/7hzeJzwT">oil barrel</a>, while aviation biofuel production cost was $0.7-1.6, needing a $110–260 crude oil barrel to <a href="/facts/Break-even/WnsHrK6c">break-even</a>.<a class="footnote-ref" id="fnref:81" href="#fn:81"><sup>81</sup></a> </p><p>As of 2020 aviation biofuel was more expensive than fossil jet kerosene,<a class="footnote-ref" id="fnref:82" href="#fn:82"><sup>82</sup></a> considering <a href="/facts/Aviation_taxation_and_subsidies/sIXKSX1F">aviation taxation and subsidies</a> at that time.<a class="footnote-ref" id="fnref:83" href="#fn:83"><sup>83</sup></a> </p><p>As of a 2021 analysis, VFA-SAF break-even cost was $2.50/US gal ($0.66/L).<a class="footnote-ref" id="fnref:84" href="#fn:84"><sup>84</sup></a> This number was generated considering credits and incentives at the time, such as <a href="/facts/LCFS/wfvcpGRD">California's LCFS</a> (Low Carbon Fuel Standard) credits and the US Environmental Protection Agency (EPA) <a href="/facts/Renewable_Fuel_Standard_(United_States)/fB1vw666">Renewable Fuel Standard</a> incentives. </p> <h2 id="sustainable-aviation-fuels">Sustainable aviation fuels</h2> <p><a href="/facts/Sustainable_biofuel/TlQHrWrm">Sustainable biofuels</a> do not use <a href="/facts/Food_crop/JoQKR5R8">food crops</a>, prime <a href="/facts/Agricultural_land/Neh9clB1">agricultural land</a> or fresh water. Sustainable aviation fuel (SAF) is certified by a third-party such as the <a href="/facts/Sustainable_biofuel/TlQHrWrm">Roundtable For Sustainable Biofuels</a>.<a class="footnote-ref" id="fnref:85" href="#fn:85"><sup>85</sup></a> </p><p>As of 2022, some 450,000 flights had used sustainable fuels as part of the fuel mix, although such fuels were ~3x more expensive than the traditional fossil jet fuel or <a href="/facts/Kerosene/DoHPYXKp">kerosene</a>.<a class="footnote-ref" id="fnref:86" href="#fn:86"><sup>86</sup></a> In 2023, SAFs account for less than 0.1% of all aviation fuels consumed.<a class="footnote-ref" id="fnref:87" href="#fn:87"><sup>87</sup></a> </p> <h3>Certification</h3> <p>A SAF sustainability certification ensures that the product satisfies criteria focused on environmental, social, and economic "<a href="/facts/Triple-bottom-line/c9thpskD">triple-bottom-line</a>" considerations. Under many emission regulation schemes, such as the <a href="/facts/European_Union_Emissions_Trading_Scheme/tVh9TLFz">European Union Emissions Trading Scheme</a> (EUTS), a certified SAF product may be exempted from carbon compliance liability costs.<a class="footnote-ref" id="fnref:88" href="#fn:88"><sup>88</sup></a> This marginally improves SAF's economic competitiveness versus fossil-based fuel.<a class="footnote-ref" id="fnref:89" href="#fn:89"><sup>89</sup></a> </p><p>The first reputable body to launch a sustainable biofuel certification system was the European-based Roundtable on Sustainable Biomaterials (RSB) NGO.<a class="footnote-ref" id="fnref:90" href="#fn:90"><sup>90</sup></a> Leading airlines and other signatories to the Sustainable Aviation Fuel Users Group (SAFUG) pledged to support RSB as their preferred certification provider.<a class="footnote-ref" id="fnref:91" href="#fn:91"><sup>91</sup></a><a class="footnote-ref" id="fnref:92" href="#fn:92"><sup>92</sup></a> </p><p>Some SAF pathways procured <a href="/facts/Renewable_Identification_Number/7HCJws2E">RIN</a> pathways under the United States's <a href="/facts/Renewable_Fuel_Standard_(United_States)/fB1vw666">renewable fuel standard</a> which can serve as an implicit certification if the RIN is a <a href="/facts/Renewable_Identification_Number/7HCJws2E">Q-RIN</a>. </p> EU RED II Recast (2018) Greenhouse gas emissions from sustainable fuels must be lower than those from the fuels they replace: at least 50% for production built before 5 October 2015, 60% after that date and 65% after 2021.<a class="footnote-ref" id="fnref:93" href="#fn:93"><sup>93</sup></a> 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 <a href="/facts/Peatland/UplolJJM">peatlands</a>). Other sustainability issues are set out in the Governance Regulation and may be covered voluntarily. ICAO 'CORSIA' GHG Reduction - Criterion 1: lifecycle reductions of at least 10% compared to fossil fuel. Carbon Stock - Criterion 1: not produced from biomass obtained from land whose uses changed after 1 January 2008 from primeval forests, wetlands or peatlands, as all these lands have high carbon stocks. Criterion 2: For <a href="/facts/Land_use_change/BAMqwQcG">land use changes</a> after 1 January 2008, (using IPCC land categories), if emissions from direct land use change (DLUC) exceed the default value of the induced land use change (ILUC), the value of the DLUC replaces the default (ILUC) value. <h3>Global impact</h3> <p>As <a href="/facts/Emissions_trading_schemes/8fLLLdAL">emissions trading schemes</a> and other carbon compliance regimes emerge, certain biofuels are likely to be exempted ("zero-rated") by governments from compliance due to their closed-loop nature, if they can demonstrate appropriate credentials. For example, in the EUTS, SAFUG's proposal was accepted<a class="footnote-ref" id="fnref:94" href="#fn:94"><sup>94</sup></a> that only fuels certified as sustainable by the RSB or similar body would be zero-rated.<a class="footnote-ref" id="fnref:95" href="#fn:95"><sup>95</sup></a> SAFUG was formed by a group of interested airlines in 2008 under the auspices of <a href="/facts/Boeing_Commercial_Airplanes/Co2Iy6E7">Boeing Commercial Airplanes</a>. Member airlines represented more than 15% of the industry, and signed a pledge to work towards SAF.<a class="footnote-ref" id="fnref:96" href="#fn:96"><sup>96</sup></a><a class="footnote-ref" id="fnref:97" href="#fn:97"><sup>97</sup></a> </p><p>In addition to SAF certification, the integrity of aviation biofuel producers and their products could be assessed by means such as <a href="/facts/Richard_Branson/khhRPD3m">Richard Branson</a>'s Carbon War Room,<a class="footnote-ref" id="fnref:98" href="#fn:98"><sup>98</sup></a> or the Renewable Jet Fuels initiative.<a class="footnote-ref" id="fnref:99" href="#fn:99"><sup>99</sup></a> The latter works with companies such as LanzaTech, SG Biofuels, AltAir, Solazyme, and Sapphire.<a class="footnote-ref" id="fnref:100" href="#fn:100"><sup>100</sup></a>[<i>verification needed</i>] </p><p>Along with her co-authors, Candelaria Bergero of the <a href="/facts/University_of_California/M9AWowUd">University of California</a>'s <a href="/facts/Earth_System_Science/dG9qMCbX">Earth System Science</a> Department stated that "main challenges to scaling up such sustainable fuel production include technology costs and process efficiencies", and widespread production would undermine <a href="/facts/Food_security/cKrQd4E9">food security</a> and <a href="/facts/Land_use/BAMqwQcG">land use</a>.<a class="footnote-ref" id="fnref:101" href="#fn:101"><sup>101</sup></a> </p> <h3>Market implementation</h3> <p>By 2019, <a href="/facts/Virgin_Australia/zraM48cK">Virgin Australia</a> had fueled more than 700 flights and flown more than one million kilometers, domestic and international, using <a href="/facts/Gevo_Inc/BogzSCz3">Gevo</a>'s alcohol-to-jet fuel.<a class="footnote-ref" id="fnref:102" href="#fn:102"><sup>102</sup></a> <a href="/facts/Virgin_Atlantic/nxvBS6gU">Virgin Atlantic</a> was working to regularly use fuel derived from the waste gases of <a href="/facts/Steel_mill/l5wz7Enp">steel mills</a>, with <a href="/facts/New_Zealand_Superannuation_Fund/aG38R8Iw">LanzaTech</a>.<a class="footnote-ref" id="fnref:103" href="#fn:103"><sup>103</sup></a> <a href="/facts/British_Airways/EbR0VE4k">British Airways</a> wanted to convert household waste into jet fuel with <a href="/facts/Fischer%25E2%2580%2593Tropsch_process/qx8noLlC">Velocys</a>.<a class="footnote-ref" id="fnref:104" href="#fn:104"><sup>104</sup></a> <a href="/facts/United_Airlines/0tCTdbNh">United Airlines</a> committed to 900 million US gal (3,400,000 m3) of sustainable aviation fuel for 10 years from Fulcrum BioEnergy (of its 4.1 billion US gal (16,000,000 m3) fuel consumption in 2018), after a $30 million investment in 2015.<a class="footnote-ref" id="fnref:105" href="#fn:105"><sup>105</sup></a> </p><p>From 2020, <a href="/facts/Qantas/uvsa55x8">Qantas</a> planned to use a 50/50 blend of SG Preston's biofuel on its Los Angeles-Australia flights. SG Preston also planned to provide fuel to <a href="/facts/JetBlue_Airways/utQuPdo6">JetBlue Airways</a> over 10 years.<a class="footnote-ref" id="fnref:106" href="#fn:106"><sup>106</sup></a> At its sites in <a href="/facts/Singapore/CQDkhUvD">Singapore</a>, <a href="/facts/Rotterdam/p8LbhGmE">Rotterdam</a> and <a href="/facts/Porvoo/y0FcfpXX">Porvoo</a>, Finland's <a href="/facts/Neste/1EGlFWMD">Neste</a> expected to improve its renewable fuel production capacity from 2.7 to 3.0 million t (6.0 to 6.6 billion lb) a year by 2020, and to increase its Singapore capacity by 1.3 million t (2.9 billion lb) to reach 4.5 million t (9.9 billion lb) in 2022 by investing €1.4 billion ($1.6 billion).<a class="footnote-ref" id="fnref:107" href="#fn:107"><sup>107</sup></a> </p><p>By 2020, <a href="/facts/International_Airlines_Group/EPkxqtEl">International Airlines Group</a> had invested $400 million to convert waste into sustainable aviation fuel with <a href="/facts/Fischer%25E2%2580%2593Tropsch_process/qx8noLlC">Velocys</a>.<a class="footnote-ref" id="fnref:108" href="#fn:108"><sup>108</sup></a> </p><p>United Airlines has expanded SAF use across multiple airports worldwide, including <a href="/facts/Amsterdam_Airport_Schiphol/Hrfvv9uz">Amsterdam</a> in 2022,<a class="footnote-ref" id="fnref:109" href="#fn:109"><sup>109</sup></a> <a href="/facts/San_Francisco_International_Airport/xG6lUyoC">San Francisco</a> and <a href="/facts/London_Heathrow/ehLEfIKS">London</a> in 2023,<a class="footnote-ref" id="fnref:110" href="#fn:110"><sup>110</sup></a> and <a href="/facts/O%2527Hare_International_Airport/1wso57wG">Chicago O'Hare</a> and <a href="/facts/Los_Angeles_International_Airport/JUjlkxzd">Los Angeles</a> in 2024.<a class="footnote-ref" id="fnref:111" href="#fn:111"><sup>111</sup></a> </p><p>In March 2024, regular use of SAF began in the Northeastern United States at <a href="/facts/John_F._Kennedy_International_Airport/UcNGmMFm">John F. Kennedy International Airport</a>, as part of a new effort by JetBlue.<a class="footnote-ref" id="fnref:112" href="#fn:112"><sup>112</sup></a> <a href="/facts/Southwest_Airlines/3DYx15Id">Southwest Airlines</a> began using sustainable jet fuel at <a href="/facts/Chicago_Midway_International_Airport/ICKzV7Eh">Chicago Midway International Airport</a> in October 2024.<a class="footnote-ref" id="fnref:113" href="#fn:113"><sup>113</sup></a> </p> <h3>Certified processes</h3> <table><tbody><tr><th>Abbreviation</th><th>Conversion Process</th><th>Possible Feedstocks</th><th>Blending Ratio</th><th>Commercialization Proposals / Projects</th></tr><tr><td>HEFA-SPK</td><td>Synthesized paraffinic kerosene produced from hydroprocessed esters and fatty acids</td><td>Bio-Oils, Animal Fat, Recycled Oils</td><td>50%</td><td>World Energy, <a href="/facts/Universal_Oil_Products/5tc4x9AT">Universal Oil Products</a>, <a href="/facts/Neste/1EGlFWMD">Neste</a>, Dynamic Fuels, EERC</td></tr><tr><td>FT-SPK</td><td>Fischer-Tropsch hydroprocessed synthesized paraffinic kerosene</td><td>Coal, Natural Gas, Biomass</td><td>50%</td><td>Fulcrum Bioenergy, Red Rock Biofuels, SG Preston, <a href="/facts/Kaidi_Finland/PAAvfqm9">Kaidi Finland</a>, <a href="/facts/Sasol/YDn92w3Y">Sasol</a>, <a href="/facts/Shell_Oil_Company/anT6Gj7S">Shell Oil Company</a>, <a href="/facts/Syntroleum/cevCsVdY">Syntroleum</a></td></tr><tr><td>SIP-HFS</td><td>Synthesized kerosene isoparaffins produced from hydroprocessed fermented sugars</td><td>Biomass-derived sugar</td><td>10%</td><td><a href="/facts/Amyris_(company)/8AbQRewE">Amyris (company)</a>, <a href="/facts/Total_S.A./4KJe17r6">Total S.A.</a></td></tr><tr><td>SPK/A</td><td>Synthesized kerosene with aromatics derived by alkylation of light aromatics from non-petroleum sources</td><td>Coal, Natural Gas, Biomass</td><td>50%</td><td><a href="/facts/Sasol/YDn92w3Y">Sasol</a></td></tr><tr><td>ATJ-SPK</td><td>Alcohol-to-jet synthetic paraffinic kerosene</td><td>Biomass-derived ethanol or isobutanol</td><td>50%</td><td><a href="/facts/Gevo/IfexDNDr">Gevo</a>, Cobalt, <a href="/facts/Universal_Oil_Products/5tc4x9AT">Universal Oil Products</a>, Lanzatech, Swedish Biofuels, Byogy</td></tr></tbody></table> <h2 id="see-also">See also</h2> <ul><li><a href="/facts/Biodiesel/M6FkfJXH">Biodiesel</a></li> <li><a href="/facts/Fossil_fuel_phase-out/edlaMjr4">Fossil fuel phase-out</a></li> <li><a href="/facts/List_of_emerging_technologies/00drktJ6">List of emerging technologies</a></li> <li><a href="/facts/Vegetable_oil_fuel/tmuALVJX">Vegetable oil fuel</a></li></ul> <h2 id="further-reading">Further reading</h2> <ul><li>Adam Klauber (<a href="/facts/Rocky_Mountain_Institute/4lff4B2x">Rocky Mountain Institute</a>); Isaac Toussie (Rocky Mountain Institute); Steve Csonka (Commercial Aviation Alternative Fuels Initiative); Barbara Bramble (<a href="/facts/National_Wildlife_Federation/mBo4Cl4z">National Wildlife Federation</a>) (Oct 23, 2017). <a href="http://aviationweek.com/technology/opinion-biofuels-sustainable-essential-aviation-s-future">"Opinion: Biofuels Sustainable, Essential To Aviation's Future"</a>. <i>Aviation Week & Space Technology</i>.</li> <li><a href="https://aim-builds.s3.amazonaws.com/gevo/Gevo+WP_aviation+fuel.pdf">"Sustainable Aviation Fuel"</a> (PDF). <a href="/facts/Gevo/IfexDNDr">Gevo</a>. December 2019. Alcohol-to-Jet Synthetic Paraffinic Kerosene Is a Proven Pathway to Deliver a Bio-Based, Low-Carbon Option to Travelers</li> <li>McKinsey & Company (Nov 2020). <a href="https://www3.weforum.org/docs/WEF_Clean_Skies_Tomorrow_SAF_Analytics_2020.pdf">Clean Skies for Tomorrow</a> (PDF) (Report). World Economic Forum. Sustainable Aviation Fuels as a Pathway to Net-Zero Aviation</li></ul> <h2 id="external-links">External links</h2> <ul><li><a href="https://www.sustainablesky.com/">"Sustainable Sky Institute"</a>. non-profit think tank/do tank focused on [...] the market transformation of the world's air transport system towards a [...] sustainable long-term future</li> <li><a href="https://aviationbenefits.org/environmental-efficiency/climate-action">"Aviation industry reducing its environmental footprint"</a>. <i>Aviation: Benefits Beyond Borders</i>. <a href="/facts/Air_Transport_Action_Group/jUjX9VgI">Air Transport Action Group</a>.</li> <li><a href="https://web.archive.org/web/20150402212013/http://cleancluster.dk/NISA">"Nordic Initiative for Sustainable Aviation"</a>. Archived from <a href="http://www.cleancluster.dk/NISA">the original</a> on 2015-04-02. Retrieved 2015-03-27. Nordic association working to promote and develop a more sustainable aviation industry, with a specific focus on alternative sustainable fuels</li> <li><a href="https://rsb.org/">"Roundtable on Sustainable Biofuels"</a>. The RSB is supporting the development of a sustainable bioeconomy</li> <li><a href="http://www.inderscience.com/jhome.php?jcode=ijsa">"International Journal of Sustainable Aviation"</a>. <a href="/facts/Inderscience_Publishers/08RkwkqC">Inderscience Publishers</a>.</li> <li><a href="https://ec.europa.eu/energy/topics/renewable-energy/biofuels/biofuels-aviation_en">"Biofuels for aviation"</a>. European Commission. 5 September 2023.</li> <li>Geoff Hunt (22 April 2021). <a href="https://www.flightglobal.com/flight-international-opinion/why-industry-needs-global-standards-for-sustainable-fuel-use/143384.article">"Why industry needs global standards for sustainable fuel use"</a>. <i>Flightglobal</i>.</li></ul> <h2 id="references">References</h2> <ol> <li id="fn:1"><p>"Sustainable aviation fuel market demand drives new product launches". Investable Universe. 2020-12-04. Retrieved 2022-12-12. Note: Investable Universe>About <a href="https://investableuniverse.com/2020/12/04/sustainable-aviation-fuel-argus-price-gunvor-group/" target="_blank">https://investableuniverse.com/2020/12/04/sustainable-aviation-fuel-argus-price-gunvor-group/</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li> <li id="fn:2"><p>Doliente, Stephen S.; et al. (10 July 2020). "Bio-aviation Fuel: A Comprehensive Review and Analysis of the Supply Chain Components" (PDF). Frontiers in Energy Research. 8: 110. Bibcode:2020FrER....8..110D. doi:10.3389/fenrg.2020.00110. <a href="https://purehost.bath.ac.uk/ws/files/205375761/Doliente_et_al_2020_Accepted_Manuscript_Frontiers_in_Energy_Research.pdf" target="_blank">https://purehost.bath.ac.uk/ws/files/205375761/Doliente_et_al_2020_Accepted_Manuscript_Frontiers_in_Energy_Research.pdf</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></p></li> <li id="fn:3"><p>"Developing Sustainable Aviation Fuel (SAF)". IATA. <a href="https://www.iata.org/en/programs/environment/sustainable-aviation-fuels/" target="_blank">https://www.iata.org/en/programs/environment/sustainable-aviation-fuels/</a> <a href="#fnref:3" class="footnote-back-ref">↩</a></p></li> <li id="fn:4"><p>Bauen, Ausilio; Howes, Jo; Bertuccioli, Luca; Chudziak, Claire (August 2009). "Review of the potential for biofuels in aviation". 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