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Southwest Airlines Purchases a Stake in Clean Flight

By Office of Energy Efficiency & Renewable Energy

Air travel accounts for 11% of transportation-related greenhouse gas emissions in the United States and is growing faster than almost any other mode of transportation. The last three decades have seen remarkable progress in curbing emissions from other modes of transportation—most notably in the rise of the electric vehicle—but aviation remains a uniquely daunting challenge. That's why the federal government and its industry partners are pouring resources into sustainable aviation fuel (SAF).

SAF, the final product of a complex process that begins with common, organic materials, has the potential to drive greenhouse gas emissions from flight all the way down to net zero. As this promising technology becomes functional, the question of how to gather and refine those materials becomes more pressing. 

On March 28, 2024, Southwest Airlines announced the acquisition of SAFFiRE Renewables, LLC, as part of the investment portfolio of its wholly owned subsidiary Southwest Airlines Renewable Ventures LLC. SAFFiRE is part of a National Renewable Energy Laboratory (NREL) project to develop SAF. In collaboration with their private-sector partners, NREL scientists invented a new method for treating and processing corn stover—the organic residue of America's massive corn harvest. Corn stover is one of several feedstocks for ethanol, which in turn can be refined into SAF.


The country produces over 400 million tons of corn stover in an average year. At least one-third of this annual yield could be repurposed for SAF production. Using this homegrown resource and other agricultural residues, the United States could produce over 7 billion gallons of SAF per year—about 20% of the projected 2050 demand. It should come as no surprise that corn stover has caught the attention of both the aviation industry and NREL researchers, who have been working around the clock to overcome the technical challenges associated with harvesting this resource.

SAFFiRE's unique pretreatment process, which was developed by using the base technology created at NREL, combines new methods with proven technologies to produce low-carbon-intensity ethanol from corn stover. This breakthrough process reduces waste and is anticipated to allow for deployment on an unprecedented scale. SAFFiRE's acquisition by Southwest Airlines, which has already set a goal to achieve net-zero carbon emissions by 2050, is a major step toward a long-anticipated boom in domestic SAF production.

As this new, clean energy industry gathers momentum, the U.S. Department of Energy will continue to pave the way with its financial resources and unique research capabilities. LanzaJet recently cut the ribbon on a U.S. Department of Energy-supported, ethanol-to-SAF production facility, and the department continues to coordinate its investments in SAF with other federal agencies through the Sustainable Aviation Fuel Grand Challenge. In February 2024, Southwest Airlines announced a $30 million investment in LanzaJet to further support these initiatives. 

The achievements of Southwest Airlines and SAFFiRE are the latest evidence that the United States, with its abundant biomass resources, can build a thriving aviation industry powered by clean fuel. 


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