• Oconnell, Deborah
• Braid, Andrew
• Rodriguez, Luis
• Kriticos, Darren
• Campbell, Peter
• Taylor, Joely
• Jovanovic, Tom
• Crawford, Debbie
• Herr, Alexander Herr - Herry
• Poole, Michael
• May, Barrie
• Oconnor, Mike
• Raison, John
• Farine, Damien

Abstract

We provide a quantitative assessment of the prospects for current and future feedstocks for bioenergy in Australia, and associated estimates of the GHG mitigation resulting from their use for production of different types of biofuels or bioelectricity. National statistics were used to estimate the current annual production from agricultural and forest production systems. Crop residues were estimated from grain production and harvest index. Wood production statistics and spatial modelling of forest growth were used to estimate quantities of pulpwood, in-forest residues, and wood processing residues. Possible new production systems for oil from algae and the oil-seed tree Pongamia pinnata, and of lignocellulosic biomass production from short rotation coppiced eucalypt crops were analysed at an exploratory level.A simple set of parameters and calculations was developed for the analysis. Defined constraints were applied including avoiding clearing of native vegetation, minimizing impacts on domestic food security, retention of a portion of agricultural and forest residues to protect soil, and minimizing the impact on local processing industries by diverting only the export fraction of grains or pulpwood to bioenergy. The parameters, data, calculations and assumptions were provided across individual feedstocks and production systems in order to provide transparency, and the opportunity for the reader to recalculate different fractions of feedstocks if they wish to apply a different set of assumptions.Within the technical and physical constraints applied in this study, it would be physically possible to replace a significant proportion of the current use of liquid fossil fuels with biofuels based on Australian-produced biomass feedstocks.The contribution that first generation biofuels could make towards replacing this was 9.6 GL/yr of ethanol from the export fraction, sufficient to replace 6.5 GL/yr of gasoline, or 34% of current gasoline usage.Oil products (waste oil, tallow and canola seed) could contribute 0.9 GL of biodiesel, equivalent to 0.8 GL/yr of diesel or 4% of current diesel usage.Cellulosic biomass from current agricultural and forestry products and residues could produce up to 9.5 GL of ethanol (including biomass from Hardwood plantation 2030).This would provide replacement for 6.4 GL/yr of gasoline, or approximately 33% of current consumption. Lignocellulose from current forestry and agricultural products and residues could provide 35.2 TWh, or approximately 13.5% of current electricity production.Up to 0.9 ML could be produced from current canola, waste oil and tallow based on our diversion assumptions. P. pinnata could produce approximately 0.8 GL of biodiesel based on 458,000 ha of new plantings.Algae, based on ponds utilising CO2-rich sources, could produce approximately 4 GL of biodiesel per year.Combined, these new production systems could replace 4.3 GL of fossil diesel, or 23% of current usage. Incorporation of coppiced eucalypt strip plantings into agricultural crop production may provide a boost in lignocellulose outputs from farming systems.Based on 5% of cleared agricultural cropping land dedicated to short rotation coppice eucalypts, 3.9 GL of ethanol could be produced (2.7 GL replacement, or 14% of current gasoline use) or 18.4 TWh of electricity (7% of current generation).Diversion of the export fraction of currently produced starch, sugar and oil to ethanol and biodiesel could mitigate approximately 5.85 Mt CO2-e, equivalent to 8.4% of current road transport emissions, or 1% of Australia's total annual emissions (Table 14 and Figure 3).Ethanol from lignocellulosic residues and products from current agricultural and forestry systems could mitigate approximately 9 Mt CO2-e by replacing fossil fuels.This would account for 13% of annual road transport emissions, or 1.6 % of total emissions in Australia.Due to the high emissions associated with electricity generation, t

Topics

• grain
• wood