Aviation fuel from perennial bioenergy crops such as miscanthus, switchgrass, and energy sorghum could dramatically reduce greenhouse gas emissions from air travel, even when accounting for land-use change, according to new research led by Madhu Khanna, director of the Institute for Sustainability, Energy and Environment and professor of agricultural and consumer economics at the University of Illinois Urbana-Champaign.
The study, supported by the Center for Advanced Bioenergy and Bioproducts Innovation (CABBI), found that scaling up sustainable aviation fuel (SAF) from these crops could cut emissions by as much as 83 percent compared with petroleum jet fuel.
For years, researchers and policymakers have debated whether converting farmland or grassland to bioenergy crops could erase greenhouse gas savings. But the Illinois-led analysis found the opposite: deep-rooted perennials store enough carbon in the soil to offset—and even outweigh—the losses from land conversion to produce them.
“This is a counterintuitive but critical finding,” said Khanna. “Expanding energy crop production on both cropland and marginal land can lower the carbon footprint of sustainable aviation fuel.”
The research team built a first-of-its-kind national model linking economics, ecology, and engineering to explore how the U.S. could meet the SAF Grand Challenge goal of replacing all 35 billion gallons of jet fuel used annually with sustainable alternatives by 2050. The results show that meeting the SAF target would require converting about 29 million hectares, or roughly 12 percent of U.S. cropland and non-cropland, to energy crops.
Fast carbon payback, big climate gains
The study found that the “carbon debt” from converting land to bioenergy crops is quickly repaid. On average, soil carbon levels recover within five to seven years and overall carbon savings (including reduction in carbon emissions) can be achieved within one year by displacing fossil fuel emissions.
“These deeply established perennial systems do more than just produce biomass; they help rebuild the soil,” said Evan DeLucia, professor emeritus of plant biology at Illinois. “By continuously sequestering carbon underground, they offer climate advantages that grow over time. The true value of these crops lies in their ability to provide long-term carbon storage while also producing renewable fuel.”
Even under conservative assumptions, SAF from these crops reduced lifecycle emissions by 75 to 83 percent relative to petroleum jet fuel.
“Our analysis shows that sustainable aviation fuel can deliver deep climate benefits if it’s produced from the right feedstocks,” Khanna said. “It also highlights the importance of policies that reward lower-carbon fuels, not just more fuel.”
Next steps for policy and industry
Sustainable aviation fuel from cellulosic feedstocks is currently several times the price of conventional jet fuel. The authors note that carbon-intensity-based incentives, rather than flat per-gallon subsidies, would more effectively drive investment in the cleanest SAF pathways.
The study also provides a blueprint for balancing land, energy, and food systems under climate policy. By integrating economic and biophysical data at fine spatial scales, it helps decision-makers visualize where and how SAF could expand sustainably.
The U.S. Department of Energy’s Office of Science, Biological and Environmental Research Program supported this research through CABBI (DE-SC0018420).
The paper “GHG Mitigation and Land Use Change Implications of Sustainable Aviation Fuel in the United States” is available at: https://doi.org/10.1038/s43247-025-02913-x
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