Sustainable plant-based bio-jet fuels could provide a competitive alternative to conventional petroleum fuels if current development and scale-up initiatives continue to push ahead successfully, scientists say.
With an estimated daily fuel demand of more than five million barrels per day, the global aviation sector is incredibly energy-intensive and almost entirely reliant on petroleum-based fuels.
Unlike other energy sectors such as ground transportation or residential and commercial buildings, the aviation industry can’t easily shift to renewable energy sources using existing technologies.
The research, published in the journal Energy and Environmental Science, provides promising evidence that optimising the biofuel production pipeline is well worth the effort.
This involves taking carbohydrate-rich plant material and using genetically modified bacteria to digest the isolated sugars into energy-dense molecules that are then chemically converted into a fuel product.
“It’s challenging to electrify aviation using batteries or fuel cells in part because of the weight restrictions on aircraft, so liquid biofuels have the potential to play a big role in greenhouse gas emissions reductions,” said Corinne Scown, a researcher at US Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab).
Currently, scientists are focused on optimising each stage of the bio-jet fuel production process.
Some researchers specialise in engineering ideal source plants – referred to as biomass – that create a high proportion of carbohydrates and a low proportion of lignin, a type of material that, as of now, is more challenging to make useful.
Meanwhile, others are developing methods for efficiently isolating the carbohydrates in non-food biomass and breaking them into sugar molecules that bacteria can digest, or “bioconvert,” into a fuel molecule.
To obtain the highest possible yield from bioconversion, other researchers are examining what genetic and environmental factors make the modified bacteria more efficient.
Once these stages are optimized, scientists can transition the technologies to commercial partners who may then modify and blend the fuels into ready-to-use products and devise strategies to industrialise the scale of production.
Given the vast amount of experimentation and innovation needed to accomplish all this, Scown and her co-authors used innovative analysis methods to assess whether the undertaking could actually reach the end game of a jet fuel alternative that airlines will want to use.
“Thankfully, the answer is they can be viable. And we’ve identified improvements that need to happen all along the conversion process to make that happen,” Scown said.