Watching grass grow in Australia : is there sufficient production potential for a biofuel industry?

Abstract

Grasses could provide an alternative to the use of food crops for biofuel production. Australia has large areas of non‐crop land that already produce grasses. However, there is currently no detailed assessment of Australia's grass production potential for bioenergy or carbon management. This paper provides an overview of grass production potential in Australia. Our approach is based on modeling native grass pastures net primary production (NPP) at a broad scale using the AussieGRASS NPP model. We assess the technical production potential of grasses for the whole of Australia; and, after excluding unsuitable production areas examine the bioenergy feedstock potential in seven regions around Australia. The paper identifies areas for grass feedstock production outside existing cropping and hay production areas. The analysis highlights areas of high production in north‐east Australia around the Tropic of Capricorn. The non‐cleared land in this extensive agricultural zone shows a promising technical production potential (266 Mt y−1) and if 15% of this land's NPP were to be transformed into ethanol, it could replace a significant part (54%) of current Australian petrol demand. We subsequently discuss these modeling results to identify areas for further improvement and future development for this approach that would produce a more robust spatial grass feedstock assessment. The paper investigates only a set of technical constraints for grass production. There will be many other constraints to consider, e.g. competing uses for grass resources from crop and animal production, and conservation needs, which will reduce the possible off‐take of grasses for energy.