Planes of the future could fly on sawdust or straw

TOULOUSE, France — Passenger jets could be chomping on straw or flying on fuel extracted from sawdust in coming years as the search widens for cleaner alternatives to kerosene, French scientists say.

The “ProBio3” project, started in early July and co-financed by a French government economic stimulus program, aims to use traditional horse-bedding materials to develop a new kind of biofuel that can be used in a 50/50 blend alongside kerosene.

“Tomorrow, planes will fly using agricultural and forest waste,” said Carole Molina-Jouve, a professor at Toulouse’s National Institute of Applied Sciences (Insa), who is coordinating the ProBio3 project.

“We already know how to set up a basic production line but we must move towards an industrial line,” she said. “We need to translate what is done in laboratories to the real environment while improving its profitability and efficiency.”

The move to use straw-based materials or wood shavings as a source of fuel is the latest in a series of biofuel ventures aimed at cutting fuel bills and pollution.

So far most attempts have been based on crop-based products, raising concerns over food shortages following recent drought.

But European planemaker Airbus, one of the program’s backers, believes woodchips and agricultural waste could be alternative fuel sources of the future.

With a budget of 24.6 million euros ($32.1 million) over eight years, ProBio3 aims to set up a profitable production chain for hydroprocessed oils, a type of biofuel which has been certified by international standards organization ASTM as useable for aviation in combination with kerosene.

Fuel made from wood and straw may seem at odds with some of the most extreme man-made conditions inside a modern jet engine, where temperatures can reach 1,600 degrees Celsius.

But scientists say they already know the basics of the process. Industrial or farm waste is broken down into sugars through enzymes, then mixed with microorganisms such as yeast, and transformed into lipids through the chemical process of fermentation. The fats obtained are then treated with hydrogen to make a type of hydrocarbon with similar properties to fossil fuels.

At Insa’s biological systems and processes engineering lab (LISBP) in Toulouse, France, where Airbus is based, Molina-Jouve removes a test tube holding a yellowish paste from a refrigerator.

“Those are large and fatty yeasts, full of synthesized lipids,” she explains, metres away from a small reactor where sugars and yeasts are combined for the fermentation process. — Reuters