Sun rises on tequila plant harvesting for biofuel
IT FUELS MEXICO’S ECONOMY and fills the world’s shot glasses, but the succulent agave plant – from which tequila is distilled – could also help quench Australia’s thirst for a low-emission biofuel.
A new study, published last week in the journal Energy and Environmental Science, shows that the agave plant (Agave tequilana) produces five times the amount of energy that’s put into growing it. This makes the ethanol derived from agave – which previously has not been farmed for bioenergy – a promising alternative to fossil fuels, offering a more eco-friendly way to power our cars and trucks.
Dr Daniel Tan, a plant physiologist from the University of Sydney and co-author of the study, says that agave produces ethanol of a similar quality to sugarcane, but has additional benefits. “The advantage is that it doesn’t need to be irrigated – it just needs to be planted, and in the rainy season it will grow really fast,” Daniel told Australian Geographic.
Faster growth than in Mexico
A trial farm established near Ayr in northern Queensland has demonstrated that agave is highly suited to Australian climates, Daniel says. “We planted the agave and did some measurements; it’s growing a bit faster than how it normally grows in Mexico,” he says. “We have more sunshine here.”
But before agave can be farmed on a wider scale, scientists need to investigate how to propagate and harvest it, and identify the exact regions where it may grow best. “The next step will be to do some computer modelling to see which areas in Australia would be most suitable,” Daniel says.
Food versus fuel
Biofuels currently account for about 0.5 per cent of Australia’s transport fuels, according to the Australian Bureau of Agricultural and Resource Economics. These are sourced mainly from the wastes that accrue when wheat and sugar crops are processed into food.
But to devote entire plantations to energy production is often seen as controversial, both internationally and in Australia, because of the potential for biofuels to displace important food crops.
Warren Flentje, an expert on carbon capture from the University of Melbourne, says agave plantations are not likely to cause such a problem. “The problem with using, say, wheat and sugar – which we have been using – is that they’re food crops,” Warren says, “so there’s the whole ‘food versus fuel’ issue.” In contrast, agave is a marginal crop that grows well in semi-arid regions, he says. “So you can make use of areas that are otherwise useless for food crops.”