Research progressing on how to spur wide use of aviation biofuels

UNIVERSITY PARK, Pa. — Slowed as much by extremely low oil prices as supply-chain and technological challenges, the effort to integrate biofuels into the nation's aviation fuel supply is nonetheless progressing, according to a researcher in Penn State's College of Agricultural Sciences.

Sustainable jet fuel continues to represent an important component of the airline industry's strategy to simultaneously reduce greenhouse-gas emissions while meeting a growing demand for international air travel, said Paul Smith, professor of bioproducts.

But developing the capability to produce the huge volume of ASTM-certified, high-energy, dense biofuels needed by the airlines, and the logistics to handle the massive amount of feedstocks necessary has been a slow process, he noted. And now, oil prices in the low $40-a-barrel range are bogging the process down further, as the cost differential between petrojet and biojet widens and, thus, increases capital risk.

"As oil prices plummet, it becomes more and more difficult to introduce any kind of biofuel into the marketplace," Smith said. "But modest volumes of biojet currently are scaling with many long-term fuel-purchasing contracts to provide biojet fuel to the airline industry."

Penn State is part of a cooperative aviation research consortium known as the Center of Excellence for Alternative Jet Fuels and Environment, funded by the Federal Aviation Administration, NASA, the Department of Defense, the Environmental Protection Agency and Transport Canada. Led by Washington State University and Massachusetts Institute of Technology, the group is a coalition of 16 leading U.S. research universities and more than 60 private-sector stakeholders committed to reducing the environmental impact of aviation.

Smith's lab, in the Department of Agricultural and Biological Engineering, is part of the group that is evaluating regional supply chains that could be used for alternative jet fuel production, including feedstock production, transportation and fuel conversion. Researchers are examining fuel-production pathways, feedstock and infrastructure requirements, and commercial fuel demand to create scenarios for future production.

In addition, the scientists are identifying potential intermediate materials and co-products for each pathway to understand potential ways to aid in making biorefineries more economical. Researchers are approaching sustainable jet fuel production holistically, considering technological, environmental, economic and social elements.

The project, Smith explained, is aimed at identifying key barriers that must be overcome throughout the alternative-jet-fuel supply chain to produce and effectively market 1 billion gallons of alternative jet fuel in the near term and 10 billion gallons in the longer term.

Smith cited several policy initiatives that are pushing biojet fuel use.

"One is them is EPA's Renewable Fuel Standard that, through a rather complex system, ultimately provides credits for cellulosic biofuels, up to $2 a gallon," he said. "And the second is, in certain markets like California and Oregon, a low-carbon fuel standard that provides credit for low-carbon-emitting fuels such as biojet fuel," he said.

These two policies somewhat even the playing field, Smith added, but it is probably going to take production on a huge scale to bring the cost of biojet down to something reasonable, combined with higher oil prices to make this all work. "Ultimately, the integrated biorefinery model, producing a mix of high-value bio-based chemicals and liquid biofuels, is the most economically viable path forward."

The goal, Smith pointed out, has been to produce aviation biofuel from lignocellulosic feedstocks, essentially the nonedible portion of plants — wood, stalks and limbs. Lignocellulose is an abundant raw material, and its use does not compete with food production. Good sources of lignocellulose are commercial operations, such as timber harvests and crop residuals, and marginal or unproductive land where grasses and woody plants are grown for that purpose.

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Last Updated June 27, 2017