URBANA, Ill. — Production of domestic sustainable aviation fuel (SAF) has increased fivefold in recent years, driven largely by production incentives enacted by the Biden administration.  Biden’s directive called for the U.S. to produce 3 billion annual gallons of SAF by 2030, enough to account for 10 percent of U.S. aviation fuel consumption. Though early moves by the Trump administration have fueled uncertainty about the future of SAF incentive funding, research is continuing at the University of Illinois (U of I) to identify potential sustainable sources for SAF production.  

One such potential SAF source, according to D.K. Lee, professor in the U of I Department of Crop Sciences, is switchgrass. “All the data that helps us estimate switchgrass suitability for SAF comes from small plot research or older forage-type switchgrass cultivars. We wanted to test high-yielding switchgrass cultivars on a larger scale to provide a more accurate picture of the benefits these new cultivars provide,” said Lee, senior author of two recent U of I research studies on switchgrass. 

Lee and the U of I research team set out to determine the most profitable cultivars of switchgrass as an energy crop. They planted three newer energy-type cultivars — Independence, Liberty, and Carthage — alongside two forage cultivars — Shawnee and Sunburst — on low-productivity marginal land in Illinois, Iowa, Nebraska, and South Dakota. After five years of growth, economic analyses  were conducted to calculate expenses and profits in each location.

“With these energy-type cultivars, farmers can put marginal lands to use and see returns after two years,” said postdoctoral researcher Muhammad Umer Arshad. “Our results can help guide decision-makers to optimize input strategies for biomass production and meet renewable energy demands.” 

Field-scale research has proven that switchgrass can thrive as an energy crop on land considered marginal for growing traditional cash crops, according to postdoctoral fellow Nictor Naomi, who led a companion study in field-scale plots in Illinois.  

“One of the many benefits of growing purpose-grown energy crops on marginal lands is ecosystem services associated with the perennial nature of energy crops. They can also potentially generate higher profits than conventional row crops on less productive land,” Namoi said. “Demonstrating ecosystem services of switchgrass, including reduction of greenhouse gas emissions and nutrient loss, will promote purpose-grown energy crops on marginal land.” 

U.S. facilities produced 38.7 million gallons of SAF in 2024, according to the U.S. Environmental Protection Agency, compared to 14 million gallons in 2023 and 7.9 million gallons in 2022. However, SAF production capacity in the U.S. will spike to nearly 800 million gallons in 2025, according to an estimate generated jointly by the Department of Agriculture and the University of Illinois.  

A major driver behind the production surge is a Biden-era Inflation Reduction Act (IRA) program that established tax credits of between $1.25 and $1.75 per gallon to purchasers of SAF. The credits were key to spurring demand for SAF, which costs about $2 more per gallon than conventional jet fuel to produce.

In Illinois, the general assembly approved legislation to create a $1.50 per gallon SAF tax credit for airlines purchasing jet fuel. In Hennepin, Ill., Marquis Sustainable Energy is currently building out its docking and storage facilities in order to construct a 120 million gallon per-year sustainable fuels plant in lockstep with the federal incentives. 

Uncertainty surrounding future federal SAF incentive funding has arisen since Trump took office. On January 28, the Department of Energy delayed delivery of $782 million in loan proceeds to Montana Renewables, the first half of a $1.44 billion loan deal the department under Biden closed on January 10. Montana Renewables plans to use the loan to increase its annual SAF production capacity from 60 million to 300 million gallons, reported Travel Weekly by Northstar.

The Trump administration has also reportedly removed some federal web pages related to SAF initiatives, including sites detailing the $244.5 million in grant funding the FAA allocated last year to SAF projects.

Illinois is a top producer of feedstock necessary for SAF development, according to the Illinois Department of Agriculture. The state also possesses the workforce, infrastructure and supportive business policies to expand SAF production, enhance SAF supply chains and increase SAF accessibility. “The shift to SAF will no doubt play an important role in Illinois’ long-term climate goals, all while promoting innovation and creating jobs for our state,” said Illinois Governor JB Pritzker, who laid out his vision for the state’s SAF industry in March 2024. 

The first U of I switchgrass study, “Comparative Economic Analysis Between Bioenergy and Forage Types of Switchgrass for Sustainable Biofuel Feedstock Production: A Data Envelopment Analysis and Cost–Benefit Analysis Approach,” is published in GCB Bioenergy [DOI: 10.1111/gcbb.70020]. 

The second study, “Field-Scale Evaluation of Ecosystem Service Benefits of Bioenergy Switchgrass,” is published in the Journal of Environmental Quality [DOI: 10.1002/jeq2.70025].