Producing biomass: Biomass types: Crops: Agave
Agave can be used as a feedstock for creating ethanol.

Benefits

Agave tequilana (blue agave) is native to the arid highlands of Mexico, where it is cultivated to produce tequila.

It uses water extremely efficiently and produces good quantities of useable biomass.

It should be a good crop for areas of Australia with seasonally limited rainfall.

Cultivars, agronomic systems and fermentation technologies have been developed during the 200 years that it has been cultivated for tequila production.

Ethanol derived from agave is likely to be superior, or at least comparable, to ethanol derived from corn, switchgrass and sugar cane in terms of energy, greenhouse-gas balances, and ethanol output, according to the 2011 paper, Life cycle energy and greenhouse gas analysis for agave-derived bioethanol, published in Energy & Environmental Science (issue 9).

This analysis concludes that agave offers promising opportunities for bioenergy production in arid or semi-arid regions, with minimum pressure on food production and water resources.

What makes the agave species water efficient?

It opens its pores (stomata) at night and takes up CO2 in the dark, which is then metabolised to release CO2 for photosynthesis during the following day, but with their stomata closed. By closing the stomata during the day, less water is lost, resulting in high water-use efficiencies. The trade-off is lower growth rates. This type of photosynthesis is known as CAM (crassulacean acid metabolism) photosynthesis.

Other species that use CAM photosynthesis are opuntia, pineapple, aloe vera, and vanilla.

This is explained further in Chapter 12, Bioenergy, of the book Photosynthesis, by Daniel Tan and Jeffrey Amthor of the University of Sydney (2013).

The bioenergy created from agave ethanol is at least 4 times the amount of energy required to produce it (Photosynthesis, Chapter 12, section 14).

Evaluating the economics of growing agave

The report, Feasibility of agave as a feedstock for biofuel production in Australia, published by RIRDC in 2010, examines the feasibility of growing Agave tequilana in conjunction with sugar cane or sorghum, to provide feedstock for the production of ethanol.

The report also:
  • explores the biology and agronomic attributes of the species
  • describes why the crop may be of interest in Australia
  • identifies potential sites of cultivation
  • proposes and costs an agronomic system.

Growing agave

There are a lot of species in the Agave genus and some of them are invasive weeds.

To find out which species are listed as weeds in Australia, check The introduced flora of Australia and its weed status, published by the CRC for Australian Weed Management in 2007. Agave tequilana is not listed as a weed.

This finding is supported by the Queensland Government’s 2010 Weed risk assessment: Blue agave (Agave tequilana) which also states that the species is best suited to sandy soils in arid and semi-arid subtropical areas.

Agave tequilana has yet to be grown commercially in Australia.

The first field experiment of Agave tequilana as a biofuel crop was planted in Australia in 2009 in the Burdekin River Irrigation Area of Queensland. Results to date are summarised by Daniel Tan, a senior lecturer in agronomy at the University of Sydney, in the Australasian Science article, ‘Tequila sunrise’ (Jan–Feb 2012).

Contacts

Giles Perryman

Refgas Australia

Dunsborough, WA. 6281,
Phone: 0447 393 363

refgas@askwm.com
Dr Daniel Tan

University of Sydney

City Rd, Darlington, NSW 2008,
Phone: 02 8627 1052

daniel.tan@sydney.edu.au
Dr Joseph A. M. Holtum

Tropical Plant Science and Agriculture, School of Marine and Tropical Biology, James Cook University

Townsville, Queensland 4811
Phone: 07 4781 4391

joseph.holtum@jcu.edu.au
Don Chambers

AUSAGAVE

Aldgate, South Australia 5154,
Phone: 08 8370 1000

info@ausagave.com.au