Research has shown that, on a full carbon life cycle basis, using the equivalent quantity of some alternative fuels could reduce CO2 emissions by around 80 per cent compared to the jet fuel they replace
In 2008, the first biofuel flight in a commercial aircraft took place. Virgin Atlantic carried out the world’s first flight of a commercial aircraft powered with biofuel, to show that it can produce less carbon dioxide than normal jet fuels. “This breakthrough will help Virgin Atlantic to fly its planes using clean fuel sooner than expected,” Sir Richard Branson, the airline’s President, said before the Boeing 747 flew from London’s Heathrow Airport to Amsterdam’s Schiphol Airport.
The flight was partially fuelled with a biofuel mixture of coconut and babassu oil in one of its four main fuel tanks. The jet carried pilots and several technicians, but no passengers. The efforts are on and the future looks bright, considering that biofuels are being seen as the alternative.
In 2011, a Boeing 737-800 carrying 171 passengers on KLM flew from Amsterdam to Paris with the airline becoming the first in the world to operate a commercial flight on bio-kerosene (cooking oil, Jet-A mix). The biofuel portion of the fuel mixture that KLM used for this latest flight was not derived from the camonila or jatropha plants. (The plants have earned attention for their high oil content and low agricultural impact.) KLM used a cooking-oil-based fuel produced by Dynamic Fuels, a joint venture between Syntroleum and Tyson Foods. KLM’s bio-kerosene was created from non-food-grade animal fat supplied as a byproduct of Tyson Foods meat processing plants. That product was refined into biofuel by Dynamic Fuels. Virgin Atlantic, British Airways and Continental have all flown commercial airliners fuelled, at least in part, with biofuels.
In December 2014, Boeing completed the world’s first flight using ‘green diesel’, a sustainable biofuel that is widely available and used in ground transportation. The eco-Demonstrator 787 flight test airplane flew with a blend of 15 per cent green diesel and 85 per cent petroleum jet fuel in the left engine. “Green diesel offers a tremendous opportunity to make sustainable aviation biofuel more available and more affordable for our customers,” said Julie Felgar, Managing Director of Environmental Strategy and Integration, Boeing Commercial Airplanes. “We will provide data from several ecoDemonstrator flights to support efforts to approve this fuel for commercial aviation and help meet our industry’s environmental goals.”
Sustainable green diesel is made from vegetable oils, waste cooking oil and waste animal fats. Boeing previously found that this fuel is chemically similar to HEFA (hydro-processed esters and fatty acids) aviation biofuel approved in 2011. Green diesel is chemically distinct and a different fuel product than ‘biodiesel,’ which also is used in ground transportation.
sustainably produced green diesel reduces carbon emissions by 50 to 90 per cent compared to fossil fuel
With production capacity of 800 million gallons (3 billion litres) in US, Europe and Asia, green diesel could rapidly supply as much as 1 per cent of global jet fuel demand. With a wholesale cost of about $3 per gallon, inclusive of US Government incentives, green diesel approaches price parity with petroleum jet fuel.
Testing aboard Dreamliner
Green diesel is among more than 25 new technologies being tested by Boeing’s eco-Demonstrator Program aboard 787 Dreamliner ZA004. The programme accelerates the testing, refinement, and use of new technologies and methods that can improve aviation’s environmental performance. On a life cycle basis, sustainably produced green diesel reduces carbon emissions by 50 to 90 per cent compared to fossil fuel, according to Finland-based Neste Oil, which supplied green diesel for the ecoDemonstrator 787. The flight test was coordinated with the US Federal Aviation Administration, Rolls-Royce and Pratt & Whitney, and EPIC Aviation blended the fuel.
The development of sustainable aviation alternative fuels could provide a very large part of the industry’s emissions-reduction strategy. Research has shown that, on a full carbon life cycle basis, using the equivalent quantity of some alternative fuels could reduce CO2 emissions by around 80 per cent compared to the jet fuel they replace.
The alternative fuels that are being investigated are second-generation feedstocks that can be grown or produced without negatively impacting food supplies, water or land use. Importantly, they are also ‘drop-in’ fuels which share the same properties as jet fuel which can be blended with the current fuel supply as they become available. Commercialisation and scaling up of the supply of alternative aviation fuels is the most important task faced for the researchers.
Policymakers need to take steps to foster research into new feedstock sources and refining processes; De-risk public and private investments in sustainable aviation fuels; Provide incentives for airlines to use alternative fuels from an early stage; Encourage stakeholders to commit to robust sustainability criteria; Understand local green growth opportunities and Establish conditions encompassing all parts of the supply chain.
The aviation industry has made it clear that it is only looking at second-generation biofuels and is determined not to repeat the mistakes made with first-generation sources, expecting any supply to be fully sustainable. The industry is working together through groups such as the Sustainable Aviation Fuel Users Group (SAFUG) and the Roundtable on Sustainable Biomaterials (RSB) to make sure that any fuels used by the industry are, in fact, sustainable.
Initiatives around the world
There is a lot of work going on in the aviation industry (by airframers, researchers, interest groups, etc) around the world to help with the commercialisation of alternative aviation fuels. Some of them are Nordic Initiative for Sustainable Aviation (Denmark, Sweden, Norway, Finland and Iceland): Aviation Initiative for Renewable Energy (Germany); Commercial Aviation Alternative Fuels Initiative (USA); Alianca Brasileira para Biocombustiveis de Aviacao (Brazil); Brazilian Biojetfuel Platform; Australian Initiative for Sustainable Alternative Fuels; Midwest Aviation Sustainable Biofuels Initiative (USA); Sustainable Aviation Fuels Northwest (USA); Bioqueroseno (Spain); SEASAFI (South East Asia) and Biofuelnet (Canada).
Advanced liquid biofuels, only option
Traditional jet fuel is a hydrocarbon, almost exclusively obtained from the kerosene fraction of crude oil. Two types of fuels are used in commercial aviation: Jet A and Jet A-1. For aviation, advanced liquid biofuels are the only low-CO2 option for substituting kerosene, as they have high specific energy content. Gaseous biofuels and electrification are definitely no option for air transportation. Advanced biofuels for aviation should use a sustainable resource to produce a fuel that can be considered as substitute for traditional jet fuel (Jet A and Jet A-1), while not consuming valuable food, land and water resources.
A big challenge facing the use of biofuels in aviation is the high quality standards requirements. Safety and fuel quality specifications are of tremendous importance in the aviation sector, however, these are not limiting the use of biofuels. The technical requirements for aviation biofuels are: a high performance fuel that can withstand a range of operational conditions; a fuel that does not compromise safety; a fuel that can directly substitute traditional jet fuel aviation; a fuel that meets stringent performance targets set by ATAG.
Globally, various sustainable feedstocks and conversion technologies for production of biofuels for aviation are being developed. In the short-term, HEFA appears to be the most promising alternative to supply significant amounts of biofuel for aviation. In the medium term, the most promising alternative is said to be drop-in FT-fuels. The aviation industry is unlikely to rely on just one type of feedstock. Aircraft will be powered by blends of biofuels from different types of feedstocks along with jet fuel. Biomass sources for advanced biojet fuels include oil crops such as jatropha and camelina, waste fats and oils, and, in the longer term, biomass sugars, algae and halophytes.
Demand for aviation fuels up
The demand for aviation fuels is expected to increase by approximately 1.5 to 3 per cent per year. There is policy at European Union level for the production and use of biofuels in the aviation sector and several initiatives established:
The High Level Group on Aviation Research in Europe has set ambitious goals including a 75 per cent reduction in CO2 emissions and a 90 per cent reduction in NOx emissions per passenger kilometre in 2050. The International Air Transport Association is committed to achieve carbon-neutral growth starting 2020 and a 50 per cent overall CO2 emissions reduction by 2050.
Accelerating R&D efforts
The European Commission in coordination with Airbus, leading European airlines (Lufthansa, Air France, KLM and British Airways) and key European biofuel producers (Neste Oil, Biomass Technology Group and UOP), launched an initiative to speed up the commercialisation of aviation biofuels in Europe. And the European Advanced Biofuels Flight Path is a road map with clear milestones to achieve an annual production of two million tonnes of sustainably produced biofuel for aviation by 2020. The Biofuels Flight Path initiative is a shared and voluntary commitment by its members to support and promote the production, storage and distribution of sustainably produced drop-in biofuels for use in aviation.
At present several hurdles prevent commercial deployment of advanced biofuels: lack of reliable overall biofuel policy, lack of policy incentives for aviation biofuels, lack of long-term offtake agreements between the biofuel producers and the aviation industry, and lack of financing.
To help address this, a number of European Commissionfunded R&D projects have been initiated to map a way forward for the introduction of sustainable biofuels to help reduce dependence on fossil fuels in air transport and reduce GHG emissions by the air industry. The Flightpath 2050, Europe’s vision for aviation, has set these goals: (a) In 2050, technologies and procedures available allow a 75 per cent reduction in CO2 emissions per passenger kilometre to support the Air Transport Action Group (ATAG) target, and a 90 per cent reduction in nitrogen oxide emissions; (b) Aircraft movements are emission-free when taxiing; (c) Air vehicles are designed and manufactured to be recyclable; (d) Europe is established as a centre of excellence on sustainable alternative fuels, including those for aviation, based on a strong European energy policy.
However, the costs of biofuels need to come down substantially and permanently which can be achieved through innovation, collaboration and the right legislation that stimulates biofuel in the airline industry.