Aviation biofuel is a biofuel used for aircraft. It is considered by some to be the primary means by which the aviation industry can reduce its carbon footprint. After a multi-year technical review from aircraft makers, engine manufacturers and oil companies, biofuels were approved for commercial use in July 2011. Since then, some airlines have experimented with using biofuels on commercial flights. The focus of the industry has now turned to second generation sustainable biofuels (sustainable aviation fuels) that do not compete with food supplies nor are major consumers of prime agricultural land or fresh water. NASA has determined that 50% aviation biofuel mixture can cut air pollution caused by air traffic by 50–70%.
The first flight using blended biofuel took place in 2008. Since then, more than 150,000 flights have used biofuels. Only five airports have regular biofuel distribution today (Bergen, Brisbane, Los Angeles, Oslo and Stockholm), with others offering occasional supply. Trials of using algae as biofuel were carried out by Lufthansa, and Virgin Atlantic as early as 2008, although there is little evidence that using algae is a reasonable source for jet biofuels. By 2015, cultivation of fatty acid methyl esters and alkenones from the algae, Isochrysis, was under research as a possible jet biofuel feedstock.
As of 2017, there was little progress in producing jet fuel from algae, with a forecast that only 3 to 5% of fuel needs could be provided from algae by 2050. Further, algae companies that formed in the early 21st century as a base for an algae biofuel industry have either closed or changed their business development toward other commodities, such as cosmetics, animal feed, or specialty oil products.
Aviation's share of the greenhouse gas emissions is poised to grow, as air travel increases and ground vehicles use more alternative fuels like ethanol and biodiesel. Currently aviation represents 2% of global emissions, but is expected to grow to 3% by 2050. In addition to building more fuel efficient aircraft and operating them more efficiently, or reducing air travel altogether, changing the fuel source is one of the few options the aviation industry has for reducing its carbon footprint. While solar, electric and hydrogen propelled aircraft are being researched, it is not expected they will be feasible in the near or medium term due to aviation's need for high power-to-weight ratio and globally compatible infrastructure.
Biodiesel that is stored for long periods of time is more likely to oxidize, especially at low temperatures, causing it to gel. Some additives improve the cold weather tolerance of biodiesel, but only by a few degrees. Nitrile-based rubber materials expand in the presence of aromatic compounds found in conventional petroleum fuel. Pure biofuels that aren't mixed with petroleum and don't contain paraffin-based additives may cause rubber seals and hoses to shrink. Manufacturers are starting to use a synthetic rubber substitute called Viton for seals and hoses. Viton isn't adversely affected by biofuels. The US Air Force has found harmful bacteria and fungi in their biofueled aircraft, and use pasteurization to disinfect them.
The International Air Transport Association (IATA) supports research, development and deployment of alternative fuels. IATA thinks a 6% share of sustainable 2nd generation biofuels is achievable by 2020, and Boeing supports a target of 1% of global aviation fuels by 2015. This is in support of the goals of the aviation industry reaching carbon neutral growth by 2020 and a 50% decrease in carbon emissions by 2050 (relative to a 2005 baseline)
A group of interested airlines has formed the Sustainable Aviation Fuel Users Group (SAFUG). The group was formed in 2008 in cooperation with support from NGOs such as Natural Resources Defense Council and The Roundtable For Sustainable Biofuels (RSB). Member airlines represent more than 15% of the industry, and all member CEOs have signed a pledge to work on the development and use of sustainable biofuels for aviation.
Jet fuel is a mixture of a large number of different hydrocarbons. The range of their sizes (molecular weights or carbon numbers) is restricted by the requirements for the product, for example, freezing point or 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.
"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. Only tests have been done so far with blending in SPK in considerably higher concentrations.
The first route involves using oil which is extracted from plant sources like Jatropha, algae, tallows, other waste oils, Babassu and Camelina to produce bio-SPK (Bio derived synthetic paraffinic Kerosene) by cracking and hydroprocessing.
The growing of algae to make jet fuel is a promising but still emerging technology. Companies working on algae jet fuel are 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
The second route involves processing solid biomass using pyrolysis to produce pyrolysis oil or gasification to produce a syngas which is then processed into FT SPK (Fischer–Tropsch Synthetic Paraffinic Kerosene).
Research is also being done on the alcohol-to-jet (ATJ) pathway where alcohols such as ethanol or butanol are de-oxygenated and processed into jet fuels.Some companies such as LanzaTech have already managed to create ATJ-SPK from CO2 in flue gases.The ethanol is hereby produced from CO in the flue gases using microbes (clostridium autoethanogenum to be exact). LanzaTech has successfully demonstrated its technology at Pilot scale in NZ –using Industrial waste gases from the steel industry as a feedstock for its microbial fermentation.
Routes that use synthetic biology to directly create hydro-carbons are being researched. Also, the production of Fischer-Tropsch hydro-carbon fuels (i.e. FT-SPK, referred to as "solar kerosine" by the project) through the use of a solar reactor is being researched by the SUN-TO-LIQUID project.
Since 2008, a large number of test flights have been conducted, and since ASTM approval in July 2011, several commercial flights with passengers have also occurred.
|2 October 2007||GreenFlight International||Aero L-29 Delfín||Waste Vegetable Oil||Greenflight International made the very first flight of an aircraft powered entirely by 100% biofuel from the Reno, Stead airport on the afternoon of 2 October 2007. There is no citation for this entry – it was made by the pilot that flew it. In November 2008 the same aircraft and flight crew flew from Reno, NV to Leesburg, FL using 100% biofuel for the first seven of the nine legs, the remaining three were completed on a 50% biofuel 50% JetA blend.|
|February 2008||Virgin Atlantic||Boeing 747||Coconut and Babassu||Virgin flew a biofuel test flight between London and Amsterdam, using a 20% blend of biofuels in one of its engines|
|December 2008||Air New Zealand||Boeing 747||Jatropha||A two-hour test flight using a 50–50 mixture of the new biofuel with Jet A-1 in the number one position Rolls Royce RB-211 engine of 747-400 ZK-NBS, was successfully completed on 30 December 2008. The engine was then removed to be scrutinised and studied to identify any differences between the Jatropha blend and regular Jet A1. No effects to performance were found.|
|January 2009||Continental Airlines||Boeing 737-800||Algae and Jatropha||Continental Airlines ran the first flight of an algae-fueled jet. The flight from Houston's George Bush Intercontinental Airport completed a circuit over the Gulf of Mexico. The pilots on board executed a series of tests at 38,000 feet (12,000 m), including a mid-flight engine shutdown. Larry Kellner, chief executive of Continental Airlines, said they had tested a drop-in fuel which meant that no modification to the engine was required. The fuel was praised for having a low flash point and sufficiently low freezing point, issues that have been problematic for other bio-fuels.|
|January 2009||Japan Airlines||Boeing 747-300||Camelina, Jatropha and algae||Japan Airlines conducted a one and a half hour flight with one engine burning a 50/50 mix of Jet-A and biofuel from the Camelina plant.|
|April 2010||US Navy||F/A-18||Camelina||The Navy tested this biofuel blend on the F⁄A-18 Super Hornet aka "Green Hornet". Results from those tests indicated the aircraft performed as expected through its full flight envelope with no degradation of capability.|
|March 2010||US Air Force||A-10||Camelina||On March 25, 2010, the United States Air Force conducted the first flight of an aircraft with all engines powered by a biofuel blend. The flight, performed on an A-10 at Eglin Air Force Base, used a 50/50 blend of JP-8 and Camelina-based fuel.|
|June 2010||Dutch Military||Ah-64 Apache Helicopter||Waste vegetable oil|
|June 2010||EADS||Diamond D42||Algae||Occurred at an air show in Berlin in June 2010.|
|November 2010||US Navy||MH-60S Seahawk||Camelina||Flown on 50⁄50 biofuel blend Nov. 18, 2010 in Patuxent River, Md. The helicopter, from Air Test and Evaluation Squadron 21 at Naval Air Station Patuxent River tested a fuel mixture made from the Camelina seed.|
|November 2010||TAM||Airbus A320||Jatropha||A 50⁄50 biofuel blend of conventional and jatropha oil|
|June 2011||Boeing||Boeing 747-8F||Camelina||Boeing flew its new model 747-8F to the Paris Air Show with all four engines burning a 15% mix of biofuel from camelina|
|June 2011||Honeywell||Gulfstream G450||Camelina||The first transatlantic biofuels flight using a 50/50 blend of camelina-based biofuel and petroleum-based fuel.|
|August 2011||US Navy||T-45||Camelina||Successfully flew a T-45 training aircraft using biofuels at the Naval Air Station (NAS) in Patuxent River, Maryland. The flight was completed by the “Salty Dogs” of Air Test and Evaluation Squadron 23 flying on biofuel mixture of 50/50 petroleum-based JP-5 jet fuel and plant-based camelina.|
|September 2011||US Navy||AV-8B||Camelina||Naval Air Warfare Center Weapons Division, China Lake performed the first bio-fuel flight test in AV-8B Harrier from Air Test and Evaluation Squadron 31.|
|October 2011||Air China||Boeing 747-400||Jatropha||Air China flew China's first flight using aviation biofuels. The flight was conducted using Chinese grown jatropha oil from PetroChina. The flight was 2 hours in duration above Beijing, and used 50% biofuel in 1 engine.|
|November 2011||Continental Airlines||Boeing 737-800||Algae||United / Continental flew a biofuel flight from IAH to ORD on algae jet fuel supplied by Solazyme. The fuel was partially derived from genetically modified algae that feed on plant waste and produce oil. It was the first biofuel-powered air service in the US.|
|November 2011||Alaska Airlines||Boeing 737 and Bombardier Q400||Algae||Alaska Airlines and its sister carrier, Horizon Air, converted 75 flights on their schedules to run on a fuel mixture of 80% kerosene and 20% biofuel derived from used cooking oil. The biofuel was made by Dynamic Fuels, a joint venture of Tyson Foods and Syntroleum Corp.|
|January 2012||Etihad Airways||Boeing 777-300ER||Waste vegetable oil||Etihad Airways conducted a biofuel flight from Abu Dhabi to Seattle using a combination of traditional jet fuel and fuel based on recycled vegetable cooking oil|
|April 2012||Qantas||Airbus A330||Refined cooking oil||Qantas used 50/50 mix of biofuel supplied by SkyNRG and Jet-A fuel in one engine for a flight from Sydney to Adelaide.|
|April 2012||Porter Airlines||Bombardier Q400||Camelina and Brassica carinata||Porter Airlines used 50/50 mix of biofuel (49% Camelina sativa and 1% Brassica carinataand) and Jet-A fuel in one engine for a flight from Toronto to Ottawa.|
|October 2012||NRC||Dassault Falcon 20||Brassica carinata||First jet to fly on 100% biofuels that meet petroleum specifications without blending. Fuel was produced by Applied Research Associates (ARA) and Chevron Lummus Global (CLG) from carinata oil supplied by Agrisoma Biosciences.|
|March 2013||Paramus Flying Club||Cessna 182 Skylane||Waste vegetable oil||First piston engine aircraft to fly with a 50/50 blend of aviation biofuel and conventional Jet-A (as specified by ASTM D7566). First piston engine aircraft to fly with a biofuel blend operating under a standard (not experimental) airworthiness certificate. Demonstration flight from North Central State Airport (KSFZ) in Rhode Island to First Flight Airport (KFFA) in North Carolina took place on March 2, 2013. The Cessna 182 had been converted under STC to be powered by an SMA jet-fuel diesel cycle piston engine, and the blended biofuel was provided by SkyNRG of Holland.|
|December 22, 2014||United States Navy||F/A-18||ATJ-SPK (Alcohol-to-Jet Synthetic Paraffinic Kerosene)||The United States Navy tested a 50/50 blend of alcohol-to-jet biofuel provided by Gevo, Inc in supersonic (above Mach 1) afterburner operations. The demonstration proved Gevo, Inc's ATJ-SPK to be a viable alternative for both military and commercial applications.|
|August 28, 2018||Spicejet Airlines, India||Bombardier Q400||Agricultural residues, non-edible oils and bio-degradable fractions of industrial and municipal wastes||India's first biofuel-powered flight was successfully tested between Dehradun to Delhi carrying DGCA officials to ascertain the feasibility of biofuel powered flights.|
|January 16, 2019||Etihad Airways||Boeing 787||Salicornia||Etihad Airways flew the first Salicornia plant biofuel powered plane from Abu Dhabi to Amsterdam using 50–50 mix of Salicornia plant with traditional fuel.|
|June 30, 2011||KLM||Boeing 737-800||Waste vegetable oil||KLM flew the world's first commercial biofuel flight, carrying 171 passengers from Amsterdam to Paris|
|July 15, 2011||Lufthansa||Airbus A321||Jatropha, Camelina and animal fats||First German commercial biofuel's flight, and the start of 6-month regular series of flights from Hamburg to Frankfurt with one of the two engines use biofuel. It officially ended on January 12, 2012 with a flight from Frankfurt to Washington and would not take biofuel further unless the biofuel was more widely produced.|
|July 20, 2011||Finnair||Airbus A319||Waste vegetable oil||The 1,500 km journey between Amsterdam and Helsinki was fuelled with a mix of 50 per cent biofuel derived from used cooking oil and 50 per cent conventional jet fuel. Finnair says it will conduct at least three weekly Amsterdam-to-Helsinki flights using the biofuel blend in both of the aircraft's engines. Refueling will be done at Amsterdam Airport Schiphol.|
|Jul 2011||Interjet||Airbus A320||Jatropha||Flight was powered by 27% jatropha between Mexico City and Tuxtla Gutierrez|
|Aug 2011||AeroMexico||Boeing 777-200||Jatropha||Aeromexico flew the world's first trans-Atlantic revenue flight, from Mexico City to Madrid with passengers|
|Oct 2011||Thomson Airways||Boeing 757-200||Waste vegetable oil||Thomson flew the UK's first commercial biofuel flight from Birmingham Airport on one engine using biofuel from used cooking oil, supplied by SkyNRG|
|Nov 2011||Continental Airlines||Boeing 737-800||Algae fuel||United / Continental flew biofuel flight from IAH to ORD on algae jet fuel, which supplied by Solazyme|
|April 19, 2012||Jetstar Airways||Airbus A320||Refined cooking oil||JQ flight 705 departed Melbourne at 0950 and arrived in Hobart at 1105 supplied by SkyNRG |
|March 13, 2013||KLM||Boeing 777-206ER||Waste vegetable oil||KLM begins weekly flights by a Boeing 777-200 between John F. Kennedy Airport in New York City, USA and Amsterdam's Schiphol Airport, Netherlands using Biofuel supplied by SkyNRG|
|May 16, 2014||KLM||Airbus A330-200||Waste vegetable oil||KLM begins weekly flights by an Airbus A330-200 between Queen Beatrix International Airport, in Oranjestad Aruba  and Amsterdam's Schiphol Airport, Netherlands (with a stop-over in Bonaire) using Biofuel supplied by SkyNRG|
|Aug 4, 2014||Gol Transportes Aéreos||Boeing 737-700||Inedible corn oil and Waste vegetable oil||Gol Flight 2152 took off from Rio Santos Dumont Airport (SDU) towards Brasilia (BSB) with a 4% mix of bio jetfuel |
|Nov 7, 2014||Scandinavian Airlines||Boeing 737-600||Waste vegetable oil||SAS Flight SK2064 flew their first ever flight using bio-fuel between Stockholm and Östersund using a 10% blend of JET A1 based on used cooking oil. It was also the first flight from Arlanda Airport|
|Nov 11, 2014||Scandinavian Airlines||Boeing 737-700||Waste vegetable oil||SAS Flight SK371 flew the first ever Norwegian domestic flight using bio-fuel between Trondheim and Oslo using a 48% blend of JET A1 based on used cooking oil|
|Mar 21, 2015||Hainan Airlines||Boeing 737-800||Waste vegetable oil||Hainan Airlines conducted China's first commercial biofuel flight carrying 156 passengers from Shanghai to Beijing. The fuel, supplied by Sinopec, was a fuel blend of approximately 50 percent aviation biofuel mixed with conventional petroleum jet fuel.|
|Mar 31, 2016||KLM||Embraer 190||Unknown||KLM operated an Embraer 190 on Biofuel between Oslo and Schiphol, Amsterdam. Embraer used these flights to measure the efficiency of the Embraer 190 on biofuel.|
|June 7, 2016||Alaska Airlines||Boeing 737-800||ATJ-SPK (Alcohol-to-Jet Synthetic Paraffinic Kerosene)||Alaska Airlines conducted the first commercial flights using alcohol-to-jet fuel made from U.S. sustainable corn. The alcohol-to-jet fuel was provided by Gevo, Inc and blended at approximately 20%. Alaska Airlines flew two flights from Seattle, Washington to San Francisco, California and from Seattle, Washington to Washington D.C.|
|Sept 8, 2016||KLM||Boeing 747-400||Waste vegetable oil||KLM signed a contract to operate all daily flights from LAX to Schiphol, Amsterdam. SkyNRG supplies the sustainable biofuel, which is made from used cooking oil by AltAir Fuels in Los Angeles. All flights from Los Angeles to Amsterdam are operated with biofuel until 2019.|
|Nov 14, 2016||Alaska Airlines||Boeing 737-800||ATJ-SPK (Alcohol-to-Jet Synthetic Paraffinic Kerosene)||Alaska Airlines conducted the first commercial flight using sustainable alternative fuel made from forest residuals. The fuel for the flight from Seattle, Washington to Washington D.C. was provided by a joint effort from Northwest Advanced Renewables Alliance (NARA) and Gevo, Inc. The flight emitted approximately 70% less CO2 than conventional jet fuel.|
|May 1, 2017||Singapore Airlines||Airbus A350-900||HEFA (hydro-processed esters and fatty acids)||Singapore Airlines begun a series of biofuel flights using A350-900 aircraft on non-stop trans-Pacific flights between Singapore and San Francisco. The project is being undertaken by Singapore Airlines in conjunction with the Civil Aviation Authority of Singapore and air navigation service providers, using enhanced flight operations and Air Traffic Management (ATM) practices along the flight route.|
By 2019, Virgin Australia has fueled more than 700 flights and flown more than 1 million kilometers, domestic and international, using Gevo, Inc's alcohol-to-jet fuel. Gevo, Inc is committed to going after the entire gallon of sustainable aviation fuel, potentially leading to a negative carbon footprint. Virgin Atlantic was working to regularly use fuel derived from the waste gases of steel mills, with LanzaTech. British Airways wanted to convert household waste into jet fuel with Velocys. United Airlines committed to 900 million US gal (3,400,000 m3) of sustainable aviation fuel for 10 years from Fulcrum BioEnergy (to be compared to its 4.1 billion US gal (16,000,000 m3) fuel consumption in 2018), after its $30 million investment in 2015, and will develop up to five biofuel factories near its hubs. From 2020 and for its Los Angeles-Australia flights, Qantas Airways will start using a 50/50 blend of SG Preston’s biofuel, also providing fuel derived from non-food plant oils to JetBlue Airways during 10 years. At its sites in Singapore, Rotterdam and Porvoo, Finland's Neste should 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 is increasing 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 life cycle assessment by the Yale School of Forestry on jatropha, one source of potential biofuels, estimated using it 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 to use. In addition, biofuels do not contain sulfur compounds and thus do not emit sulfur dioxide.
Many different standards exist for certification of sustainable biofuels. One such standard often cited by airlines is the one developed by the Roundtable For Sustainable Biofuels. Nearly all such standards include a minimum amount of greenhouse gas reduction and consideration that biofuels do not compete with food.