Invasive weeds offer potential as biofuel source

Weeds collected near Ipswich in South-East Queensland, Australia, could one day fuel homes and industries, thanks to new research exploring their potential as a renewable biofuel.

Scientists from the University of Queensland’s Queensland Alliance for Agriculture and Food Innovation (QAAFI) have identified several invasive plant species that could be transformed into biofuels, offering a low-cost, sustainable alternative to fossil-based energy.

The study assessed 15 species of environmental weeds growing west of Brisbane, evaluating their suitability for conversion into biomass pellets that can be used as solid biofuel.

Two vines in particular - Brazilian Nightshade and Climbing Asparagus - stood out for their high lignin content, a crucial component for biofuel production.

“Historically, the global biofuel pellet market has relied heavily on forest biomass,” said lead researcher Dr Bruno de Almeida Moreira. “But under Australian regulations, wood pellets are no longer classified as renewable, which has prompted us to look for viable alternatives.”

“These weeds contain around 25 per cent lignin - comparable to wood - and we’ve shown they can be used to produce market-grade biofuel pellets.”

The research was carried out in collaboration with Ipswich-based startup WorkEco, with support from a seed grant provided by the Australian Government’s Strategic University Reform Fund (SURF).

Associate Professor Sudhir Yadav, co-author of the study and head of UQ’s AgriSustain lab, said the work could help the agriculture sector reduce its environmental footprint while creating new opportunities in the renewable energy space.

“Agencies such as the Australian Renewable Energy Agency forecast that bioenergy could account for 20 per cent of national energy demand by 2050,” said Dr Yadav. “It’s an ambitious target, but one that’s within reach with the right innovations.”

The team is also exploring the conversion of low-value agricultural by-products - such as crop stalks, straw, woodchips, and even animal manure - into usable biofuels and other functional products.

“This kind of work could generate revenue for local startups, help councils manage green waste, and most importantly, reduce the environmental burden,” Dr Yadav added.

However, he acknowledged that relying solely on invasive weeds is not a long-term solution.

“There’s a natural limit to the supply of environmental weeds. So, we’re also investigating green waste from households and councils, and even crops like sorghum as potential feedstocks.”

The findings were published in the journal Sustainable Energy Technologies and Assessments.