Researchers at the University of Illinois Urbana-Champaign have conducted a comprehensive analysis to determine the most effective biofuel crops for producing sustainable aviation fuels (SAF) in the US. Their study, published in the journal Environmental Science and Technology, examined four key biofuels: corn stover, energy sorghum, miscanthus, and switchgrass, identifying which feedstock best suits specific regions across US to support localized SAF production strategies.
This study will help growers and policymakers select the feedstocks most suited to meeting goals like reducing production costs, lowering greenhouse gas emissions and building soil carbon stocks.
The study emphasised the complexity of selecting economically and environmentally viable biofuel feedstocks. “It’s a huge task to weigh all the factors that make a particular biofuel feedstock economically or environmentally viable. You have to consider all other potential uses for the land used to grow the crop, the costs of establishing a new crop, and numerous other factors like weather, soil carbon and the productivity of a given crop in a particular location,” said Madhu Khanna, a professor of agricultural and consumer economics at the University of Illinois Urbana-Champaign and the director of the U. of I. Institute for Sustainability, Energy and Environment. Khanna led the study with Xinxin Fan, a postdoctoral researcher at iSEE.
“There’s also the cost of converting different feedstocks into biofuels and the greenhouse gas emissions associated with growing and transporting them to a refinery,” Xinxin Fan said.
The researchers divided the rainfed areas of the continental US—stretching from the Dakotas down to Texas and eastward—into 1.5-mile-square plots and categoried them into four zones: Great Plains, Midwest, Northeast, and Southeast. Factors considered included land use alternatives, establishment costs, and the carbon footprint associated with each feedstock from cultivation to refinery transport.
Key findings indicated the optimal feedstock varies by location and the policy incentives in place. For instance, miscanthus showed the lowest cost of greenhouse gas abatement in the Midwest, while switchgrass was most effective in the South. Corn stover, despite having the lowest break-even price, presented the highest abatement cost due to its high greenhouse gas intensity and Energy sorghum was identified as the most suitable in parts of the Great Plains. The analysis revealed that each crop excels in a particular region based on factors such as reducing production costs, lowering greenhouse gas emissions, and enhancing soil carbon stocks.
The U.S., which consumes 23 billion gallons of jet fuel annually, has launched the Sustainable Aviation Fuel Grand Challenge to increase SAF production to 3 billion gallons by 2030 and 35 billion by 2050, aiming for a 50% reduction in lifecycle greenhouse gas emissions. The implications of these findings are significant to ensure that SAF production is both sustainable and cost-effective, aligning with broader environmental goals and the specific agricultural landscapes of each region.