Product Code Database
An aviation biofuel (also known as bio-jet fuel, Note: Investable Universe>About sustainable aviation fuel (SAF), or bio-aviation fuel (BAF)) is a biofuel used to power aircraft. The International Air Transport Association (IATA) considers it a key element in reducing the environmental impact of aviation. Aviation biofuel is used to decarbonize medium and long-haul air travel. These types of travel generate the most emissions and could extend the life of older aircraft types by lowering their carbon footprint. Synthetic paraffinic kerosene (SPK) refers to any non-petroleum-based fuel designed to replace kerosene jet fuel, which is often, but not always, made from biomass.
Biofuels are biomass-derived fuels from plants, animals, or waste; depending on which type of biomass is used, they could lower emissions by 20–98% compared to conventional jet fuel. The first test flight using blended biofuel was in 2008, and in 2011, blended fuels with 50% biofuels were allowed on commercial flights. In 2023 SAF production was 600 million liters, representing 0.2% of global jet fuel use. By 2024, SAF production was to increase to 1.3 billion liters (1 million tonnes), representing 0.3% of global jet fuel consumption and 11% of global renewable fuel production. This increase came as major US production facilities delayed their ramp-up until 2025, having initially been expected to reach 1.9 billion liters.
Aviation biofuel can be produced from plant or animal sources such as Jatropha, algae, tallows, waste oils, palm oil, Babassu oil, and Camelina (bio-SPK); from solid biomass using pyrolysis processed with a Fischer–Tropsch process (FT-SPK); with an alcohol-to-jet (ATJ) process from waste fermentation; or from synthetic biology through a Chemical reactor. Small piston engines can be modified to burn ethanol.
Sustainable biofuels are an alternative to electrofuels. Sustainable aviation fuel is certified as being sustainable by a third-party organisation.
SAF technology faces significant challenges due to feedstock constraints. The oils and fats known as hydrotreated esters and fatty acids (Hefa), crucial for SAF production, are in limited supply as demand increases. Although advanced Electrofuel technology, which combines waste with Green hydrogen, presents a promising solution, it is still under development and comes with high costs. To overcome these issues, SAF developers are exploring more readily available feedstocks such as woody biomass and agricultural and municipal waste, aiming to produce lower-carbon jet fuel more sustainably and efficiently.
Jatropha oil, a non-food oil used as a biofuel, lowers emissions by 50–80% compared to Jet-A1, a kerosene-based fuel. Jatropha, used for biodiesel, can thrive on marginal land where most plants produce low crop yield. 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.
Palm oil cultivation is constrained by scarce land resources and its expansion to forestland causes biodiversity loss, along with direct and indirect emissions due to land-use change. Neste Corporation's renewable products include a refining byproduct of food-grade palm oil, the oily waste skimmed from the palm oil mill's wastewater. Other Neste sources are used cooking oil from deep fryers and animal fats. Neste's sustainable aviation fuel is used by Lufthansa; Air France and KLM announced 2030 SAF targets in 2022 including multi-year purchase contracts totaling over 2.4 million tonnes of SAF from Neste, TotalEnergies, and DG Fuels.
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. This lessens the need to grow crops specifically for fuel, which in itself is energy intensive and increases 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. 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.
NASA has determined that 50% aviation biofuel mixture can cut particulate emissions caused by air traffic by 50–70%. Note: Firefox 'does not trust' the weblink 2022-12-22. Biofuels do not contain sulfur compounds and thus do not emit sulfur dioxide. While, it may be true that the burning of biofuels do not emit sulfur compounds, some forms of production, such as pyrolysis, can in fact produce sulfur compounds and other pollutants. Some potential pollutants that could be released are hydrogen sulfide and different nitrogen compounds like hydrogen cyanide, ammonia, and nitrogen dioxide. It is important to note that there are other forms of biofuel production that may not have the same emmissions.''
The production of biofuels can disrupt ecosystems. Most viable forms of biofuel production require a lot of land and water usage. Taking land from and disrupting water distribution in the ecosystem in which the biofuel farm is located may have noticeable effects on the surrounding wildlife, which in turn can impact adjacent ecosystems and therefore the region's ecology. Because of the scaling required to make aviation biofuel mainstream, the impact of land usage is a current hindrance to the growth of the biofuel industry. Potential solutions to this issue have begun to surface. For example, algae farms can produce a lot more biofuel per unit of area than crops.
In 2009, the IATA committed to achieving carbon-neutral growth by 2020, and to halve carbon emissions by 2050.
In 2010, Boeing announced a target 1% of global aviation fuels by 2015.
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. The safety and performance of jet fuel used in passenger flights is certified by ASTM International. Biofuels were approved for commercial use after a multi-year technical review from aircraft makers, engine manufacturers and oil companies. Thereafter some airlines experimented with biofuels on commercial flights. As of July 2020, seven annexes to D7566 were published, including various biofuel types:
In December 2011, the FAA awarded US$7.7 million to eight companies to develop Substitute good sustainable fuels, especially from alcohols, sugars, biomass, and organic matter such as , within its and programs.
Biofuel provider Solena filed for bankruptcy in 2015.
By 2015, cultivation of fatty acid methyl esters and from the algae, Isochrysis, was under research.
By 2016, Thomas Brueck of Munich TU was forecasting that algaculture could provide 3–5% of jet fuel needs by 2050.
In fall 2016, the International Civil Aviation Organization announced plans for multiple measures including the development and deployment of sustainable aviation fuels.
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 production of by 2012-2014. By 2017 most companies had disappeared or changed their to focus on other markets.
In 2019, 0.1% of fuel was SAF: The International Air Transport Association (IATA) supported the adoption of Sustainable Aviation fuel, aiming in 2019 for 2% share by 2025: .
In early 2021, Boeing's CEO Dave Calhoun said drop-in sustainable aviation fuels are "the only answer between now and 2050" to reduce carbon emissions. 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.
The 2022 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." In November, 2022, sustainable aviation fuels were a topic at COP26.
As of 2023, 90% of biofuel was made from oilseed and sugarcane which are grown for this purpose only.
"Drop-in" biofuels are biofuels that are interchangeable with conventional fuels. Deriving "drop-in" jet fuel from bio-based sources is ASTM approved via two routes. ASTM has found it safe to blend in 50% SPK into regular jet fuels. Tests have been done with blending synthetic paraffinic kerosene (SPK) in considerably higher concentrations.
The SUN-to-LIQUID project (2016-2019) was a European Union Horizon 2020-funded research initiative that demonstrated the production of sustainable aviation fuel directly from sunlight, water, and carbon dioxide. The project utilised a solar thermochemical process involving a high-temperature solar reactor to produce synthesis gas (syngas), which was then converted into jet fuel through Fischer-Tropsch synthesis. On June 13, 2019, researchers at the IMDEA Energy Institute in Móstoles, Spain successfully demonstrated the complete production chain, marking a significant milestone in solar fuel technology. The project consortium included partners from seven European countries and Switzerland, led by Bauhaus Luftfahrt, and received support from the Swiss State Secretariat for Education, Research and Innovation. While the demonstration proved the technical feasibility of producing drop-in aviation fuel from renewable sources without competing for agricultural land, the technology remained at an early stage with challenges related to scaling and economic viability requiring further development.
Alder Fuels developed a technology to convert lignocellulosic biomass, including forestry and agricultural residues, into a hydrocarbon-rich intermediate product called "greencrude" through pyrolysis. This greencrude can subsequently be processed in conventional petroleum refineries using existing infrastructure to produce Drop-in fuel. The company's process utilises waste biomass feedstocks that do not compete with food production, addressing one of the sustainability concerns associated with first-generation biofuels.
Universal Fuel Technologies developed Flexiforming technology, a catalytic process designed to convert various feedstocks, including byproducts from existing renewable fuel production, into sustainable aviation fuel. The technology has feedstock flexibility, allowing for the processing of multiple biomass-derived inputs through a single conversion pathway.
Arcadia eFuels developed a power-to-liquid facility at the port of Vordingborg, Denmark, utilising a process that combines water electrolysis powered by renewable electricity with carbon dioxide capture to produce synthetic aviation fuel. The process involves generating green hydrogen through electrolysis, which is then combined with captured CO2 to create synthesis gas (syngas), subsequently converted to jet fuel via Fischer-Tropsch or similar gas-to-liquid processes.
The United States Air Force found harmful bacteria and fungi in their biofueled aircraft, and use pasteurization to disinfect them.
As of a 2021 analysis, VFA-SAF break-even cost was . This number was generated considering credits and incentives at the time, such as LCFS (Low Carbon Fuel Standard) credits and the US Environmental Protection Agency (EPA) Renewable Fuel Standard incentives.
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 kerosene. In 2023, SAFs account for less than 0.1% of all aviation fuels consumed. Throughout 2024, Alaska Airlines was the leader among U.S. airlines in SAF implementation, accounting for 0.68% of its fuel usage. Other major airlines including United, Delta and JetBlue used SAF in roughly .3% of fuel.
The first reputable body to launch a sustainable biofuel certification system was the European-based Roundtable on Sustainable Biomaterials (RSB) NGO. Leading airlines and other signatories to the Sustainable Aviation Fuel Users Group (SAFUG) pledged to support RSB as their preferred certification provider.
Some SAF pathways procured RIN pathways under the United States's renewable fuel standard which can serve as an implicit certification if the RIN is a Q-RIN.
In addition to SAF certification, the integrity of aviation biofuel producers and their products could be assessed by means such as Richard Branson's Carbon War Room, or the Renewable Jet Fuels initiative. The latter works with companies such as LanzaTech, SG Biofuels, AltAir, Solazyme, and Sapphire.
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.
From 2020, Qantas 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 JetBlue over 10 years. At its sites in Singapore, Rotterdam and Porvoo, Finland's Neste expected to improve its renewable fuel production capacity from a year by 2020, and to increase its Singapore capacity by to reach in 2022 by investing €1.4 billion ($1.6 billion).
By 2020, International Airlines Group had invested $400 million to convert waste into sustainable aviation fuel with Velocys.
United Airlines has expanded SAF use across multiple airports worldwide, including Amsterdam in 2022, San Francisco and Heathrow Airport in 2023, and Chicago O'Hare and Los Angeles in 2024.
In March 2024, regular use of SAF began in the Northeastern United States at John F. Kennedy International Airport, as part of a new effort by JetBlue. Southwest Airlines began using sustainable jet fuel at Chicago Midway International Airport in October 2024.
History
The first flight using blended biofuel took place in 2008. Virgin Atlantic used it fly a commercial airliner, using feedstocks such as algae. Airlines representing more than 15% of the industry formed the Sustainable Aviation Fuel Users Group, with support from NGOs such as Natural Resources Defense Council and The Roundtable For Sustainable Biofuels by 2008. They pledged to develop sustainable biofuels for aviation. That year, Boeing was co-chair of the Algal Biomass Organization, joined by air carriers and biofuel technology developer UOP LLC (Honeywell).
Production
Jet fuel is a mixture of various . The mixture is restricted by product requirements, for example, freezing point and smoke point. Jet fuels are sometimes classified as 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.
Alternative production routes
Several research initiatives and companies have reported work on technologies intended to produce synthetic hydrocarbons and sustainable aviation fuels (SAF).
Piston engines
Small piston engines can be modified to burn ethanol. Swift Fuel, a biofuel alternative to avgas, was approved as a test fuel by ASTM International in December 2009.
Technical challenges
Nitrile-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. Synthetic rubber substitutes that are not adversely affected by biofuels, such as Viton, for seals and hoses are available.
Aromatics and cycloalkanes
SAF is generally required to be blended with fossil fuel—because jet fuel needs [[cycloalkanes]] and aromatics, which are generally deficient in SAF; as well as the more prevalent in SAF n-alkanes and [[wikt:isoalkane|isoalkanes]].
Economics
In 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. By 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 break-even. As of 2024, SAF represents just 0.3% of global aviation fuel.
aviation biofuel was more expensive than fossil jet kerosene, considering aviation taxation and subsidies at that time.
Sustainable aviation fuels
Sustainable biofuels do not use , prime agricultural land or fresh water. Sustainable aviation fuel (SAF) is certified by a third-party such as the Roundtable For Sustainable Biofuels.
Certification
A SAF sustainability certification ensures that the product satisfies 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. This marginally improves SAF's economic competitiveness versus fossil-based fuel.
Global impact
As emissions trading schemes 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 that only fuels certified as sustainable by the RSB or similar body would be zero-rated. SAFUG was formed by a group of interested airlines in 2008 under the auspices of Boeing Commercial Airplanes. Member airlines represented more than 15% of the industry, and signed a pledge to work towards SAF.
Market implementation
By 2019, Virgin Australia had fueled more than 700 flights and flown more than one million kilometers, domestic and international, using Gevo Inc's alcohol-to-jet fuel. Virgin Atlantic was working to regularly use fuel derived from the waste gases of , with LanzaTech. British Airways wanted to convert household waste into jet fuel with Velocys. United Airlines committed to of sustainable aviation fuel for 10 years from Fulcrum BioEnergy (of its fuel consumption in 2018), after a $30 million investment in 2015.
Certified processes
World Energy, Universal Oil Products, Neste, Dynamic Fuels, EERC Fulcrum Bioenergy, Red Rock Biofuels, SG Preston, Kaidi Finland, Sasol, Shell Oil Company, Syntroleum Amyris (company), TotalEnergies Sasol Gevo, Cobalt, Universal Oil Products, Lanzatech, Swedish Biofuels, Byogy
See also
Further reading
External links
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