About two percent of global greenhouse emissions come from carbon dioxide emitted from aviation and that number is expected to grow by three to four percent every year, according to the International Civil Aviation Organization (ICAO).
With the global push to address climate change taking off, the aviation industry is being forced to find ways to address its environmental impact. As companies and organizations have begun research on how to tackle this issue, sustainable aviation fuels (SAF) have emerged as an early front-runner.
“Aviation has an issue, right,” Chris Cooper, VP of Renewable Aviation at Neste—a Finland-based oil refining and marketing company—told Avionics International. “We create greenhouse gas emissions through combustion, and so the opportunity is to change the fuel or the energy source within an aircraft. Some people choose to offset and offsetting in some instances, planting trees or paying for a tree to do what it's already doing, right, but the consideration that we want to share with folks is that in renewable aviation, we have an opportunity to exchange an energy source that is sustainable.”
Alternative fuels are an energy source derived from non-petroleum resources that help reduce the demand for fossil fuels. Alternate fuels can produce fewer emissions and provide cost savings compared to fossil fuels. There are a wide variety of alternative fuels in use, some of the top sources include ethanol, electricity, biodiesel, natural gas, propane, and hydrogen.
SAF is aviation fuel derived from renewable sources or waste feedstocks and there are eight approved SAF pathways. SAF can include fuels of biogenic origin, fuels from hybrid feedstocks, liquid hydrogen, recycled carbon-based fuels, and electro-fuels, Pedro Piris-Cabezas, director of sustainable international transport and lead senior economist at the Environmental Defense Fund, told Avionics International via email.
The benefit of SAF is that it has lower greenhouse gas emissions than traditional fuel.
“SAF provides a benefit when it has lower GHG emissions across its lifecycle than fossil jet fuel,” Piris-Cabezas said. “But SAF is not carbon neutral as is often reported, and the emissions reductions vary depending on the SAF as well. Because SAFs burn more cleanly than fossil fuels, high-integrity SAFs can, in principle, deliver local health benefits to communities by helping cut air pollution around airports. This may also help reduce the non-CO2 effects that occur when fuel is combusted and releases NOx gases, water vapor, and soot (black carbon, organic compounds, sulfur, and nitrogen) causing a warming effect known as radiative forcing.”
It is important to consider the feedstock or where the SAF is derived from when deciding if the fuel is truly sustainable, former U.S. chief climate change negotiator and current director of disruption technologies at ENGIE Impact, the New York-based energy, and sustainability management company, told Avionics International.