Case Studies

‘Tequila’-powered biofuel performer

Associate Professor Daniel Tan from University of Sydney with agave plants (1)

Rather than be used for tequila, agave plants could be used as potent biofuel feedstock, following findings by an Australian/UK research team.

The drought-hardy plant could be established in semi-arid Australia as an environmentally friendly fuel source, say researchers at the University of Sydney, University of Exeter and University of Adelaide.

The high-sugar succulent produced better bioethanol than corn and sugarcane in terms of water consumption and quality, greenhouse gas emissions and yield.

It could also help produce ethanol for hand sanitiser, currently in high demand during the COVID-19 pandemic.

Agave is grown for biofuel on the Atherton Tablelands in Far North Queensland by MSF Sugar.

Associate Professor Daniel Tan (pictured) from the Sydney Institute of Agriculture said: “It can grow in semi-arid areas without irrigation; and it does not compete with food crops or put demands on limited water and fertiliser supplies. Agave is heat and drought-tolerant and can survive Australia’s hot summers.”

Lead author Dr Xiaoyu Yan from the University of Exeter, who led the lifecycle assessment, said: “Our analysis highlights the possibilities for bioethanol production from agave grown in semi-arid Australia, causing minimum pressure on food production and water resources.

“The results suggest that bioethanol derived from agave is superior to that from corn and sugarcane in terms of water consumption and quality, greenhouse gas emissions, as well as ethanol output.”

The analysis showed an annual bioethanol yield of 7414 litres/ha from with five-year-old plants. US corn ethanol yields 3800 litres/ha. While sugarcane yields 9900 litres/ha, agave outperforms on a range of measures, including freshwater eutrophication, marine ecotoxicity and – crucially – water consumption. Agave uses 69 percent less water than sugarcane and 46 percent less water than corn for the same yield.

This study used chemical analyses of agave from a pilot agave farm in Kalamia Estate, near Ayr, in Queensland, undertaken by Dr Kendall Corbin for her University of Adelaide PhD, supervised by Professor Rachel Burton.

“It is fabulous that the results of my chemical analysis can be used in both an economic and environmental footprint study and have real-world applications”, Dr Corbin said.

“The economic analysis suggests that a first generation of bioethanol production from agave is currently not commercially viable without government support, given the recent collapse in the world oil price,” said Associate Professor Tan. “However, this may change with the emerging demand for new ethanol-based healthcare products, such as hand sanitisers.”

Agave grows primarily in Mexico but is also found in parts of the United States and central and tropical South America. It is a succulent with a large rosette of thick leaves and a shallow root system. Tolerant to high temperatures and drought, it is adapted to future global warming.

Source: University of Sydney