• Mohit Chandak

Sustainable aviation fuel


Aviation contributes to about 2.5% of global emissions (for reference, global transportation contributes to about 16% of emissions out of which 12% is from road transportation). While actual emissions differ from flight to flight, type of aircraft, passenger utilization etc., most organizations tend to estimate them to be around 120-150kg CO2 per passenger per hour. (Read more about it in one of our previous articles.)


What to expect today

  • What is Sustainable Aviation Fuel (SAF)?

  • How are corporations approaching SAF?


What is Sustainable Aviation Fuel (SAF)?

Image Source: Photo by Marina Hinic from Pexels

SAF is typically a biofuel made from renewable biomass and waste resources. It has the potential to deliver the performance of petroleum-based jet fuel but with a fraction of its carbon footprint, giving airlines solid footing for decoupling greenhouse gas (GHG) emissions from flight. SAF is used to power aircraft that have similar properties to conventional jet fuel but with a smaller carbon footprint. According to the U.S. Environmental Protection Agency, SAFs lower carbon intensity makes it an important solution for reducing aviation GHGs, which make up 9%–12% of U.S. transportation GHG emissions.


Is SAF better for the environment?

SAF that is currently commercially available can reduce GHG emissions by up to 80% on a life-cycle emissions basis as compared to fossil fuels, offering airlines a way to become greener while continuing to fly. In addition, since SAFs are made from biomass crops and other sources, besides reducing GHGs, SAFs helps in:

  • farmers by bringing extra revenue for them by growing biomass crops

  • in getting extra environmental services, such as controlling erosion, pollution, etc.

  • in increasing biodiversity and store carbon in the soil, which can deliver on-farm benefits and other environmental benefits

  • in reducing nutrient losses and improving soil quality


Challenges in implementing SAF


Though there are innumerable benefits of SAF to both economy and environment, there are a few challenges before this can be truly scaled up:


  • While there appears to be some demand for SAF, meeting it is another question entirely. Only 100 million liters of SAF has been used in 2021 and IATA says it expects to see SAF production hit 7.9 billion liters by 2025, however, it would still meet just 2% of the overall fuel requirement

  • Stimulating the necessary investment in capital to ramp up the production is another challenge. With no compensation mechanism for airlines for the environmental benefits of using the fuel, there are small, limited markets for aviation biofuels at the current price which is higher than for conventional jet fuel

  • The sustainable fuel sector is still not mature yet. Beyond research, demonstrating a biojet technology at a sufficient scale is a critical step in the development to convince investors of the viability of the technology and complete the fuel approval process


The need to significantly increase the production of SAF was recognised by the US Biden administration with the launch of a Sustainable Aviation Fuel Grand Challenge to produce three billion gallons of the fuel a year by 2030

Source: ICAO, CNBC, Bioenergy Technologies Office


How are corporations approaching SAF?

Image Source: Photo by Ahmed Muntasir from Pexels

In this section, we will explore how airline companies, plane manufacturers and startups are approaching the development and use of SAFs.

Airlines - United, American Airlines, Emirates

  • For over a decade United has led the industry in developing SAF. It made history in December 2021 as it was the first commercial flight with passengers on board to use 100% drop-in SAF for one of the aircraft’s two engines. United has invested more in SAF production than any other airline till date. Read more about this here. (Below is United’s timeline of investment in SAF)


Image Source: United
  • American Airlines announced that it has finalized a new SAF offtake agreement with Aemetis. The agreement brings the airline’s total SAF commitment to more than 120 million gallons. It has agreed to take delivery of 16 million gallons of Aemetis SAF annually over a seven-year period beginning in 2024. The SAF will be blended with traditional jet fuel at a 40/60 ratio to align with international standards.

  • Emirates and GE Aviation committed to test flight programmes using 100% Sustainable Aviation Fuel by the end of 2022

Airplane manufacturers - Airbus, Boeing

  • Airbus tried and tested 100% SAF in a few of their aircrafts in last year. The company hopes to introduce the world's first zero-emission aircraft by 2035. Currently, all Airbus planes can be operated using 50% SAF blended with traditional jet fuel, though the company hopes to increase that to 100% by 2030

  • Boeing began SAF testing flights in 2008, helped gain approval for commercial use in 2011 and enabled airplane delivery flights with SAF starting in 2012. The 2018 Boeing ecoDemonstrator conducted the industry's first 100 percent SAF commercial airplane test flight on a 777 Freighter in partnership with FedEx. In the beginning of 2022, it bought two million gallons (7.5 million liters) of blended SAF, that is the largest SAF purchase till date

Engine manufacturers - Rolls Royce, Pratt and Whitney

  • Rolls-Royce has conducted the first tests of 100% SAF in 2021 in a business jet engine, as part of its ambition to reach net zero carbon by 2050

  • All of Pratt and Whitney’s current engines are ready to accept the certified maximum blend of 50% with conventional jet fuel. Additional testing and certification work will be required to approve SAF blends as a 100% fuel replacement, which could ultimately reduce an aircraft’s carbon emissions by up to 80%

Startup - Cemtiva, Twelve

  • United Airlines announced a $5 million investment in Cemvita Factory Inc., a biotech startup based in Houston. It is attempting to develop a method to convert carbon dioxide into sources of SAF. Cemvita Factory raised over more than $10 million to date

  • Twelve is a chemical technology company based in Berkeley, California. Their technology is an electrochemical reactor that uses CO2, water and renewable energy to make thousands of chemicals, materials and fuels that today are made by refining fossil fuels. It also made the world's first jet fuel from CO2 electrolysis

Source: Bloomberg


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