This thesis investigated the potential and cost of reducing Australia’s environmental impact, particularly greenhouse gas emissions, through ethanol biorefineries. Bio-ethanol reduces greenhouse gas emissions by reducing tailpipe emissions and displacing fuel production. Ethanol synergies may be used to further reduce emissions by processing waste streams into various products and displacing other more greenhouse gas intensive processes.
Full life cycle assessments were conducted on 20 different biorefinery configurations at 12 locations throughout Australia. The variables accounted for in the assessments were greenhouse gas emissions and energy production, with qualitative investigations into sustainability, water consumption and ecosystem influences.
The economics of producing ethanol and its co-products were examined concurrently, to establish the incremental cost of greenhouse gas mitigation for each process and to provide approximate commercial information for potential investors. The sites and configurations that produce the greatest net greenhouse gas reduction, net energy balance and net present value respectively are shown in Table 0-1.
The profitability of Australian ethanol plants has improved dramatically due the recent spikes in world energy prices. Thus, the Australian ethanol industry will grow of its own volition; not requiring government support as once was anticipated.
Hydrous ethanol achieves greater reduction in greenhouse gas emissions than anhydrous, however the economic imperative is to produce anhydrous ethanol. Government intervention to enhance the economics of hydrous ethanol production could mitigate carbon dioxide emissions for less than $10 per tonne.
Biorefineries that generate power from biogas further reduce net greenhouse gas emissions and liberate greater amounts of energy. This configuration is economically superior in South Australia and Western Australia where electricity prices are high. Renewable Energy Certificate prices of less than $40 are required to make it also economically superior in the National Electricity Market. The current price is $30 per certificate. The expansion of the Mandatory Renewable Energy Target from 2% is necessary to increase the demand, and hence prices, of certificates, so that electricity from biogas becomes viable.
Ethanol biorefineries have great potential to reduce Australia’s environmental impact. The economic viability of the projects ensures that this potential will be realised. The establishment of this industry will also provide the government with relatively inexpensive avenues for greenhouse gas mitigation, so that the issue of Australian contribution to climate change may be addressed with lesser effects on the economy.