Добірка наукової літератури з теми "Biomass energy Australia"

The use of forest biomass for bioenergy in Australia represents only 1% of total energy production but is being recognized for having the potential to deliver low-cost and low-emission, renewable energy solutions. This review addresses the potential of forest biomass for bioenergy production in Australia relative to the amount of biomass energy measures available for production, harvest and transport, conversion, distribution and emission. Thirty-Five Australian studies on forest biomass for bioenergy are reviewed and categorized under five hierarchical terms delimiting the level of assessment on the biomass potential. Most of these studies assess the amount of biomass at a production level using measures such as the allometric volume equation and form factor assumptions linked to forest inventory data or applied in-field weighing of samples to predict the theoretical potential of forest biomass across an area or region. However, when estimating the potential of forest biomass for bioenergy production, it is essential to consider the entire supply chain that includes many limitations and reductions on the recovery of the forest biomass from production in the field to distribution to the network. This review reiterated definitions for theoretical, available, technological, economic and environmental biomass potential and identified missing links between them in the Australian literature. There is a need for further research on the forest biomass potential to explore lower cost and lowest net emission solutions as a replacement to fossil resources for energy production in Australia but methods the could provide promising solutions are available and can be applied to address this gap.

In Australia, and globally, hydrogen is primarily produced from natural gas via steam methane reforming. This process also produces CO2, which is typically vented to the atmosphere. Under this configuration, the hydrogen produced is known as grey hydrogen (carbon producing). However, if the CO2 from this process is captured and stored after it is produced, the hydrogen product is CO2-neutral, or ‘blue hydrogen’. To enable production of blue hydrogen from existing natural gas steam methane reformers (SMRs) in Australia, gasification of biomass/bio waste can be utilised to produce fuel gas for use in a SMR-based hydrogen plant, and the CO2 in the shifted syngas can be removed as pure CO2 either for sequestration, enhanced oil recovery, or enhanced coal bed methane recovery. Australian liquefied natural gas that is exported and utilised as feedstock to existing SMRs in other countries can incorporate carbon emission reduction techniques for blue hydrogen production. The use of bio-derived syngas as fuel will generate hydrogen with only bio-derived CO2 emissions. Additional carbon credit can be obtained by replacing petrol or diesel consuming automobiles with fuel cell vehicles powered by hydrogen derived from gasification of biomass.

Current (1997–2006) and future (2050) global field biomass bioenergy potential was estimated based on FAO (2009) production statistics and estimations of climate change impacts on agriculture according to emission scenario B1 of IPCC. The annual energy potential of raw biomass obtained from crop residues and bioenergy crops cultivated in fields set aside from food production is at present 122–133 EJ, 86–93 EJ or 47–50 EJ, when a vegetarian, moderate or affluent diet is followed, respectively. In 2050, with changes in climate and increases in population, field bioenergy production potential could be 101–110 EJ, 57–61 EJ and 44–47 EJ, following equivalent diets. Of the potential field bioenergy production, 39–42 EJ now and 38–41 EJ in 2050 would derive from crop residues. The residue potential depends, however, on local climate, and may be considerably lower than the technically harvestable potential, when soil quality and sustainable development are considered. Arable land could be used for bioenergy crops, particularly in Australia, South and Central America and the USA. If crop production technology was improved in areas where environmental conditions allow more efficient food production, such as the former Soviet Union, large areas in Europe could also produce bioenergy in set aside fields. The realistic potential and sustainability of field bioenergy production are discussed.;

Harnessing sustainably sourced forest biomass for renewable energy is well-established in some parts of the developed world. Forest-based bioenergy has the potential to offset carbon dioxide emissions from fossil fuels, thereby playing a role in climate change mitigation. Despite having an established commercial forestry industry, with large quantities of residue generated each year, there is limited use for forest biomass for renewable energy in Queensland, and Australia more broadly. The objective of this study was to identify the carbon dioxide mitigation potential of replacing fossil fuels with bioenergy generated from forest harvest residues harnessed from commercial plantations of Pinus species in southeast Queensland. An empirical-based full carbon accounting model (FullCAM) was used to simulate the accumulation of carbon in harvest residues. The results from the FullCAM modelling were further analysed to identify the energy substitution and greenhouse gas (GHG) emissions offsets of three bioenergy scenarios. The results of the analysis suggest that the greatest opportunity to avoid or offset emissions is achieved when combined heat and power using residue feedstocks replaces coal-fired electricity. The results of this study suggest that forest residue bioenergy is a viable alternative to traditional energy sources, offering substantive emission reductions, with the potential to contribute towards renewable energy and emission reduction targets in Queensland. The approach used in this case study will be valuable to other regions exploring bioenergy generation from forest or other biomass residues.

Australia’s large potential forest bioenergy resource is considerably underutilised, due largely to its high delivered costs. Drying forest biomass at the roadside can potentially reduce its delivered cost through weight reduction and increased net calorific value. There has been little research on the impact of roadside drying for Australian conditions and plantation species. This study compared delivered costs for three forest biomass types—Eucalyptus globulus plantation whole trees and logging residue (LR)-disaggregated (LR conventional) or aggregated (LR fuel-adapted)—and three roadside storage scenarios—no storage, ≤two-month storage and optimal storage—to supply a hypothetical thermal power plant in south-west Western Australia. The study was performed using a tactical linear programming tool (MCPlan). Roadside storage reduced delivered costs, with optimal storage (storage for up to 14 months) producing the lowest costs. Delivered costs were inversely related to forest biomass spatial density due to transport cost reductions. Whole trees, which had the highest spatial density, stored under the optimal storage scenario had the lowest delivered costs (AUD 7.89/MWh) while LR conventional, with the lowest spatial density, had the highest delivered costs when delivered without storage (AUD 15.51/MWh). For both LR types, two-month storage achieved ~60% of the savings from the optimal storage scenario but only 23% of the savings for whole trees. The findings suggested that roadside drying and high forest biomass spatial density are critical to reducing forest biomass delivered costs.

Mallee biomass is considered to be a second-generation renewable feedstock in Australia and will play an important role in bioenergy development in Australia. Its production is of large-scale, low cost, small carbon footprint and high energy efficiency. However, biomass as a direct fuel is widely dispersed, bulky, fibrous and of high moisture content and low energy density. High logistic cost, poor grindability and mismatch of fuel property with coal are some of the key issues that impede biomass utilisation for power generation. Therefore, innovations are in urgent need to improve biomass volumetric energy densification, grindability and good fuel matching if co-fired with coal. Biomass pyrolysis is a flexible and low-cost approach that can be deployed for this purpose. Via pyrolysis, the bulky biomass can be converted to biomass-derived high-energy-density fuels such as biochar and/or bio-oil. So far there has been a lack of fundamental understanding of mallee biomass pyrolysis and properties of the fuel products.The series of study in this PhD thesis aims to investigate the production of such high-energy- density fuels obtained from mallee pyrolysis and to obtain some new knowledge on properties of the resultant fuels and their implications to practical applications. Particularly, the research has been designed and carried out to use pyrolysis as a pretreatment technology for the production of biochar, bio-oil and bioslurry fuels. The main outcomes of this study are summarised as follows.Firstly, biochars were produced from the pyrolysis of centimetre-sized particles of mallee wood at 300-500°C using a fixed-bed reactor under slow-heating conditions. The data show that at pyrolysis temperatures > 320°C, biochar as a fuel has similar fuel H/C and O/C ratios compared to Collie coal which is the only coal being mined in WA. Converting biomass to biochar leads to a substantial increase in fuel mass energy density from ~10 GJ/tonne of green biomass to ~28 GJ/tonne of biochars prepared from pyrolysis at 320°C, in comparison to 26 GJ/tonne for Collie coal. However, there is little improvement in fuel volumetric energy density, which is still around 7-9 GJ/m[superscript]3 in comparison to 17 GJ/m[superscript]3 of Collie coal. Biochars are still bulky and grinding is required for volumetric energy densification. Biochar grindability experiments have shown that the fuel grindability increases drastically even at pyrolysis temperature as low as 300°C. Further increase in pyrolysis temperature to 500°C leads to only small increase in biochar grindability. Under the grinding conditions, a significant size reduction (34-66 % cumulative volumetric size <75 μm) of biochars can be achieved within 4 minutes grinding (in comparison to only 19% for biomass after 15 minutes grinding), leading to a significant increase in volumetric energy density (e.g. from ~8 to ~19 GJ/m[superscript]3 for biochar prepared from pyrolysis at 400°C). Whereas grinding raw biomass typically result in large and fibrous particles, grinding biochar produce short and round particles highly favourable for fuel applications.Secondly, it is found that the pyrolysis of different biomass components produced biochars with distinct characteristics, largely because of the differences in the biological structure of these components. Leaf biochars showed the poorest grindability due to the presence of abundant tough oil glands in leaf. Even for the biochar prepared from the pyrolysis of leaf at 800°C, the oil gland enclosures remained largely intact after grinding. Biochars produced from leaf, bark and wood components also have significant differences in ash properties. Even with low ash content, wood biochars have low Si/K and Ca/K ratios, suggesting these biochars may have a high slagging propensity in comparison to bark and leaf biochars.Thirdly, bio-oil and biochar were also produced from pyrolysis of micron-size wood particle using a fluidised-bed reactor system under fast-heating conditions. The excellent grindability of biochar had enabled desirable particle size reduction of biochar into fine particles which can be suspended into bio-oil for the preparation of bioslurry fuels. The data have demonstrated that bioslurry fuels have desired fuel and rheological characteristics that met the requirements for combustion and gasification applications. Depending on biochar loading, the volumetric energy density of bioslurry is up to 23.2 GJ/m[superscript]3, achieving a significant energy densification (by a factor > 4) in comparison to green wood chips. Bioslurry fuels with high biochar concentrations (11-20 wt%) showed non-Newtonian characteristics with pseudoplastic behaviour. The flow behaviour index, n decreases with the increasing of biochar concentration. Bioslurry with higher biochar concentrations has also demonstrated thixotropic behaviour. The bioslurry fuels also have low viscosity (<453 mPa.s) and are pumpable at both room and elevated temperatures. The concentrations of Ca, K, N and S in bioslurry are below the limits of slurry fuel guidelines.Fourthly, bio-oil is extracted using biodiesel to produce two fractions, a biodiesel-rich fraction (also referred as bio-oil/biodiesel blend) and a bio-oil rich fraction. The results has shown that the compounds (mainly phenolic) extracted from bio-oil into the biodiesel-rich fraction reduces the surface tension of the resulted biodiesel/bio-oil blends that are known as potential liquid transport fuels. The bio-oil rich fraction is mixed with ground biochar to produce a bioslurry fuel. It is found that bioslurry fuels with 10% and 20% biochar loading prepared from the bio-oil rich fraction of biodiesel extraction at a biodiesel to bio-oil blend ratio 0.67 have similar fuel properties (e.g. density, surface tension, volumetric energy density and stability) in comparison to those prepared using the original whole bio-oil. The slurry fuels have exhibited non-Newtonian with pseudoplastic characteristics and good pumpability desirable for fuel handling. The viscoelastic behaviour of the slurry fuels also has shown dominantly fluid-like behaviour in the linear viscoelastic region therefore favourable for atomization in practical applications. This study proposes a new bio-oil utilisation strategy via coproduction of a biodiesel/bio-oil blend and a bioslurry fuel. The biodiesel/bio-oil blend utilises a proportion of bio-oil compounds (relatively high value small volume) as a liquid transportation fuel. The bioslurry fuel is prepared by mixing the rest low-quality bio-oil rich fractions (relatively low value and high volume) with ground biochar, suitable for stationary applications such as combustion and gasification.Overall, the present research has generated valuable data, knowledge and fundamental understanding on advanced fuels from mallee biomass using pyrolysis as a pre-treatment step. The flexibility of pyrolysis process enables conversion of bulky, low fuel quality mallee biomass to biofuels of high volumetric energy density favourable to reduce logistic cost associated with direct use of biomass. The significance structural, fuel and ash properties differences among various mallee biomass components were also revealed. The production of bioslurry fuels as a mixture of bio-oil and biochar is not only to further enhance the transportability/handling of mallee biomass but most importantly the slurry quality highly matched requirements in stationary applications such as combustion and gasification. The co-production of bioslurry with bio-oil/biodiesel extraction was firstly reported in this field. Such a new strategy, which uses high-quality extractable bio-oil compounds into bio-oil/biodiesel blend as a liquid transportation fuel and utilises the low-quality bio-oil rich fraction left after extraction for bioslurry preparation, offers significant benefits for optimised use of bio-oil.

This thesis contributes to the development of thermochemical liquefaction as a process for biofuel production. This study investigated residues from sugarcane, energy crops and algae. The potential amount of energy from biomass resources were investigated for each region in Australia. The work was at a larger laboratory scale than other workers which allowed more detailed characterisation of each sample and more thorough investigation of the fuels. Importantly, various bio-crude oils were successfully generated which were comparable with heavy fossil fuel based oils by changing only the processing conditions and without catalytic upgrading.

University of Technology, Sydney. Institute for Sustainable Futures.
After decades of stability the Australian electricity market is undergoing changes. Current government targets aim to reduce greenhouse gas emissions by 5% and raise renewable electricity production to 45 TWh by 2020. In addition, increases to natural gas prices, aging generation assets and falling electricity demand have had an impact in recent years. Uncertainties exist around current policies, including the carbon pricing mechanism and the renewable energy target, but in light of Australian and international ambitions to lower greenhouse gas emissions the deployment of renewable energy technologies is essential. In recent years wind and photovoltaic installations have shown the highest renewable energy growth rates while concentrating solar power has struggled, despite Australia having some of the best natural resources for concentrating solar power in the world and some selected government funding. Reasons for the slow uptake include the comparatively high cost and lack of financial incentives. While technology costs are expected to decrease by up to 40% by 2020 through deployment as well as research and development, other cost reduction options have to be identified to promote short-term implementation in electricity markets such as Australia where the wholesale cost is low. To overcome the cost problem and to address other relevant implementation barriers this research analyses the hybridisation of concentrating solar power with biomass and waste feedstocks. The results of this research include: ▪ a recommendation for a categorisation system for CSP hybrid plants based on the degree of interconnection of the plant components ▪ the availability of combined resources to generate up to 33.5 TWh per year and abate 27 million tonnes CO₂ annually ▪ an analysis of the most suitable CSP technologies for hybridisation ▪ a technology comparison showing CSP cost reductions through hybridisation of up to 40% ▪ the identification of cost differences of up to 31% between different hybrid concepts ▪ an analysis showing that the current economic and policy settings are the most significant implementation barriers ▪ two case studies with different biomass and waste feedstocks requiring power purchase agreements of AU$ 100-155/MWh. Based on the various benefits of concentrating solar power hybrid plants, this research analyses the potential role of this technological pairing in Australia’s transition to a low carbon energy future. The research concludes that concentrating solar power hybrid plants, not only hybridised with biomass and waste feedstocks, can immediately enable a lower cost deployment of concentrating solar power facilities in Australia. The technology, deployment and operation of the first hybrid installations would provide market participants with valuable lessons and would have the potential to reconfigure the electricity market towards more sustainable generation. This could help promote the development of future low-cost concentrating solar power plants in Australia.

Co-firing coal and biomass offers a sustainable renewable energy option. However, slagging and fouling have been identified as some of the major operational challenges associated with co-firing. The chemistry of individual fuels can be used to determine the slagging potential of the blend. Previously, we have developed a numerical slagging index (NSI) based on the ash content in coal and the chemical properties of the coal ash. The NSI has been tested on a wide range of coals, and very good prediction results were obtained. In this paper, the slagging potential of Nigerian coal and other coals from Australia, Colombia and South Africa have been numerically evaluated. The predicted results using the NSI indicate that the Nigerian coal has relatively low slagging propensity when compared with other coals tested in this paper. One of the Australian coals seems to have lower slagging potential, and this may be attributed to the extraordinary low ash content for the coal, as reported. It has been observed that the silica-rich coal ash composition can be used to select suitable coals that could be co-fired with the alkali-rich biomass, with low operational risk. However, detail information on the chemical properties of blend and the particle-particle interaction can improve the performance of the assessment tool.

A new, efficient process for reducing the ash content, drying and fractionating raw lignocellulosic materials into chemicals and a dry solid end product, eminently suitable as a fuel for conventional boilers or for milling to a fine powder for gas turbine firing, shows strong potential for renewable power generation. The dry, low ash solids, termed “Cellulig™”, will also be suitable for gasification and to drive gas turbines. Sustainable liquid and gaseous fuels will become increasingly necessary in the 21st century to reduce dependence on imported fuels, to replace dwindling supplies of oil and natural gas and to avoid environmental damage from green house gases. Convertech Group Ltd. has built a demonstration biomass processing plant at Burnham, Canterbury, New Zealand, with investment from the energy industry and the Australian Energy Research and Development Council. The essential chemical and process engineering elements are described and the current and future development opportunities outlined.