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1.
Debbie F. Crawford Michael H. O'Connor Tom Jovanovic Alexander Herr Robert John Raison Deborah A. O'Connell Tim Baynes 《Global Change Biology Bioenergy》2016,8(4):707-722
This paper provides spatial estimates of potentially available biomass for bioenergy in Australia in 2010, 2030 and 2050 (under clearly stated assumptions) for the following biomass sources: crop stubble, native grasses, pulpwood and residues (created either during forest harvesting or wood processing) from plantations and native forests, bagasse, organic municipal solid waste and new short‐rotation tree crops. For each biomass type, we estimated annual potential availability at the finest scale possible with readily accessible data, and then aggregated to make estimates for each of 60 Statistical Divisions (administrative areas) across Australia. The potentially available lignocellulosic biomass is estimated at approximately 80 Mt per year, with the major contributors of crop stubble (27.7 Mt per year), grasses (19.7 Mt per year) and forest plantations (10.9 Mt per year). Over the next 20–40 years, total potentially available biomass could increase to 100–115 Mt per year, with new plantings of short‐rotation trees being the major source of the increase (14.7 Mt per year by 2030 and 29.3 Mt per year by 2050). We exclude oilseeds, algae and ‘regrowth’, that is woody vegetation naturally regenerating on previously cleared land, which may be important in several regions of Australia (Australian Forestry 77 , 2014, 1; Global Change Biology Bioenergy 7 , 2015, 497). We briefly discuss some of the challenges to providing a reliable and sustainable supply of the large amounts of biomass required to build a bioenergy industry of significant scale. More detailed regional analyses, including of the costs of delivered biomass, logistics and economics of harvest, transport and storage, competing markets for biomass and a full assessment of the sustainability of production are needed to underpin investment in specific conversion facilities (e.g. Opportunities for forest bioenergy: An assessment of the environmental and economic opportunities and constraints associated with bioenergy production from biomass resources in two prospective regions of Australia, 2011a). 相似文献
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Life cycle assessment of native plants and marginal lands for bioenergy agriculture in Kentucky as a model for south-eastern USA 总被引:1,自引:0,他引:1
SETH DEBOLT J. ELLIOTT CAMPBELL† RAY SMITH Jr. ‡ MICHAEL MONTROSS§ JOZSEF STORK 《Global Change Biology Bioenergy》2009,1(4):308-316
The Brookings Institute analysis rate both Lexington and Louisville, Kentucky (USA) as two of the nation's largest carbon emitters. This high carbon footprint is largely due to the fact that 95% of electricity is produced from coal. Kentucky has limited options for electric power production from low carbon sources such as solar, wind, geothermal, and hydroelectric. Other states (TN, IN, OH, WV, and IL) in this region are similarly limited in renewable energy capacity. Bioenergy agriculture could account for a proportion of renewable energy needs, but to what extent is unclear. Herein, we found that abandoned agricultural land, not including land that is in fallow or crop rotation, aquatic ecosystems, nor plant-life that had passed through secondary ecological succession totaled 1.9 Mha and abandoned mine-land totaled 0.3 Mha, which combined accounted for 21% of Kentucky's land mass. A life cycle assessment was performed based on local yield and agronomic data for native grass bioenergy agriculture. These data showed that utilizing Kentucky's marginal land to grow native C 4 grasses for cellulosic ethanol and bioelectricity may account for up to 13.3% and 17.2% of the states 2 trillion MJ energy consumption and reduce green house gas emissions by 68% relative to gasoline. 相似文献
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Besides ruminant animals and their wastes, soil is an important regula ting medium in carbon cycling. The soil can be both a contributor to climate cha nge and a recipient of impacts. In the past, land cultivation has generally resu lted in considerable depletion of soil organic matter and the release of greenho use gases (GHGs) into the atmosphere. The observation in the North-South Transec t of Eastern China showed that climate change and land use strongly impact all s oil processes and GHG exchanges between the soil and the atmosphere. Soil manage ment can restore organic carbon by enhancing soil structure and fertility and by doing so mitigating the negative impacts of atmospheric greenhouses on climate. A wide estimation carried out in China shows that carbon sequestration potentia l is about 77.2 MMt C/a (ranging from 26.1—128.3 MMt C/a) using proposed IPCC a ctivities during the next fifty years. 相似文献
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Besides ruminant animals and their wastes, soil is an important regulating medium incarbon cycling. The soil can be both a contributor to climate change and a recipient of impacts. Inthe past, land cultivation has generally resulted in considerable depletion of soil organic matter andthe release of greenhouse gases (GHGs) into the atmosphere. The observation in the North-South Transect of Eastern China showed that climate change and land use strongly impact all soil proc-esses and GHG exchanges between the soil and the atmosphere. Soil management can restoreorganic carbon by enhancing soil structure and fertility and by doing so mitigating the negative im-pacts of atmospheric greenhouses on climate. A wide estimation carried out in China shows that carbon sequestration potential is about 77.2 MMt C/a (ranging from 26.1-128.3 MMt C/a) using proposed IPCC activities during the next fifty years. 相似文献
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Benoît Gabrielle Nicolas Nguyen The Pauline Maupu Estelle Vial 《Global Change Biology Bioenergy》2013,5(1):30-42
Short rotation coppices (SRC) are considered prime candidates for biomass production, yielding good‐quality feedstock that is easy to harvest. Besides technical, social and economical aspects, environmental issues are important to be taken into account when developing SRC. Here, we evaluated the environmental impacts of delivering 1 GJ of heat from eucalyptus SRC using life cycle assessment (LCA), based on management scenarios involving different rotations lengths, fertilizer input rates, stem densities and harvest methods. Compared to equivalent fossil chains, all eucalyptus scenarios achieved savings of fossil energy and greenhouse gas (GHG) emissions in the 80–90% range, and had generally lower impacts, except for eutrophication. The 3 year rotation scenario was the most energy and GHG‐intensive, whereas manual felling for the longer rotations resulted in twofold larger photochemical ozone impacts compared to the other scenarios. Transportation of wood chips and fertilization were the top two contributors to the impacts, the latter being more important with the shorter rotation lengths due to the evergreen character of eucalyptus. The possibility of including ecosystem carbon dynamics was also investigated, by translating the temporary sequestration of atmospheric CO2 in the above and belowground biomass of eucalyptus as CO2 savings using various published equivalence factors. This offset the life cycle GHG emissions of heat provision from eucalyptus SRC by 70–400%. 相似文献
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Improvements in Life Cycle Energy Efficiency and Greenhouse Gas Emissions of Corn-Ethanol 总被引:1,自引:0,他引:1
Adam J. Liska Haishun S. Yang Virgil R. Bremer Terry J. Klopfenstein Daniel T. Walters Galen E. Erickson Kenneth G. Cassman 《Journal of Industrial Ecology》2009,13(1):58-74
Corn-ethanol production is expanding rapidly with the adoption of improved technologies to increase energy efficiency and profitability in crop production, ethanol conversion, and coproduct use. Life cycle assessment can evaluate the impact of these changes on environmental performance metrics. To this end, we analyzed the life cycles of corn-ethanol systems accounting for the majority of U.S. capacity to estimate greenhouse gas (GHG) emissions and energy efficiencies on the basis of updated values for crop management and yields, biorefinery operation, and coproduct utilization. Direct-effect GHG emissions were estimated to be equivalent to a 48% to 59% reduction compared to gasoline, a twofold to threefold greater reduction than reported in previous studies. Ethanol-to-petroleum output/input ratios ranged from 10:1 to 13:1 but could be increased to 19:1 if farmers adopted high-yield progressive crop and soil management practices. An advanced closed-loop biorefinery with anaerobic digestion reduced GHG emissions by 67% and increased the net energy ratio to 2.2, from 1.5 to 1.8 for the most common systems. Such improved technologies have the potential to move corn-ethanol closer to the hypothetical performance of cellulosic biofuels. Likewise, the larger GHG reductions estimated in this study allow a greater buffer for inclusion of indirect-effect land-use change emissions while still meeting regulatory GHG reduction targets. These results suggest that corn-ethanol systems have substantially greater potential to mitigate GHG emissions and reduce dependence on imported petroleum for transportation fuels than reported previously. 相似文献
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New fuel regulations based on life cycle greenhouse gas (GHG) emissions have focused renewed attention on life cycle models of biofuels. The BESS model estimates 25% lower life cycle GHG emissions for corn ethanol than does the well-known GREET model, which raises questions about which model is more accurate. I develop a life cycle metamodel to compare the GREET and BESS models in detail and to explain why the results from these models diverge. I find two main reasons for the divergence: (1) BESS models a more efficient biorefinery than is modeled in the cases to which its results have been compared, and (2) in several instances BESS fails to properly count upstream emissions. Adjustments to BESS to account for these differences raise the estimated global warming intensity (not including land use change) of the corn ethanol pathway considered in that model from 45 to 61 g CO2 e MJ−1 . Adjusting GREET to use BESS's biorefinery performance and coproduct credit assumptions reduces the GREET estimate from 64 to 61 g CO2 e MJ−1 . Although this analysis explains the gap between the two models, both models would be improved with better data on corn production practices and by better treatment of agricultural inputs. 相似文献
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Santiago R. Verón Esteban G. Jobbágy Carlos M. Di Bella José M. Paruelo Robert B. Jackson 《Global Change Biology Bioenergy》2012,4(6):634-641
As the environmental and economic consequences of fossil‐fuel use become clear, land is increasingly targeted as a source of bioenergy. We explore the potential for generating electricity from biomass vulnerable to fires as an ecologic and socioeconomic opportunity that can reduce the risk of greenhouse gas generation from wildfires and help to create incentives to preserve natural and seminatural vegetation and prevent its conversion to agriculture, including biofuel crops. On the basis of a global analysis of the energy generation and spatial distribution of fires, we show that between 2003 and 2010, global fires consumed ~8300 ± 592 PJ yr?1 of energy, equivalent to ~36–44% of the global electricity consumption in 2008 and >100% national consumption in 57 countries. Forests/woodlands, cultivated areas, shrublands, and grasslands contributed 53%, 19%, 16%, and 3.5% of the global energy released by fires. Although many agroecological, socioeconomic, and engineering challenges need to be overcome before diverting the energy lost in fires into more useable forms, done cautiously it could reconcile habitat preservation with economic yields in natural systems. 相似文献
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Sarah J. Gerssen‐Gondelach Birka Wicke Andre P. C. Faaij 《Global Change Biology Bioenergy》2017,9(4):725-742
The implementation of measures to increase productivity and resource efficiency in food and bioenergy chains as well as to more sustainably manage land use can significantly increase the biofuel production potential while limiting the risk of causing indirect land use change (ILUC). However, the application of these measures may influence the greenhouse gas (GHG) balance and other environmental impacts of agricultural and biofuel production. This study applies a novel, integrated approach to assess the environmental impacts of agricultural and biofuel production for three ILUC mitigation scenarios, representing a low, medium and high miscanthus‐based ethanol production potential, and for three agricultural intensification pathways in terms of sustainability in Lublin province in 2020. Generally, the ILUC mitigation scenarios attain lower net annual emissions compared to a baseline scenario that excludes ILUC mitigation and bioethanol production. However, the reduction potential significantly depends on the intensification pathway considered. For example, in the moderate ILUC mitigation scenario, the net annual GHG emissions in the case study are 2.3 MtCO2‐eq yr?1 (1.8 tCO2‐eq ha?1 yr?1) for conventional intensification and ?0.8 MtCO2‐eq yr?1 (?0.6 tCO2‐eq ha?1 yr?1) for sustainable intensification, compared to 3.0 MtCO2‐eq yr?1 (2.3 tCO2‐eq ha?1 yr?1) in the baseline scenario. In addition, the intensification pathway is found to be more influential for the GHG balance than the ILUC mitigation scenario, indicating the importance of how agricultural intensification is implemented in practice. Furthermore, when the net emissions are included in the assessment of GHG emissions from bioenergy, the ILUC mitigation scenarios often abate GHG emissions compared to gasoline. But sustainable intensification is required to attain GHG abatement potentials of 90% or higher. A qualitative assessment of the impacts on biodiversity, water quantity and quality, soil quality and air quality also emphasizes the importance of sustainable intensification. 相似文献
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随着石化燃料的日益减少,以植物生物质为原料的可再生生物燃料成为石化燃料的理想替代品。然而微生物降解生物质效率低下,是生物燃料生产过程中一大难题,因此开发效率高、稳定性强的微生物酶制剂显得尤为重要。近年来,宏基因组技术的发展为生物燃料的生产提供了多种新型酶制剂。宏基因组技术是直接提取环境样品中的总DNA,通过构建文库,筛选目的基因或功能基因的方法,在用于燃料生产的新型酶制剂的开发中发挥着重要作用。本文概述了宏基因组技术的实施策略,总结了包括纤维素酶、蛋白酶、酯酶、脂肪酶等多种酶资源开发的最新研究进展,并综合和讨论了通过酶法将木质纤维素等生物材料有效转化为生物燃料的途径,为新酶的开发提供了新思路。 相似文献
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Ingrid M. Lubbers Matty P. Berg Gerlinde B. De Deyn Wim H. van der Putten Jan Willem van Groenigen 《Global Change Biology》2020,26(3):1886-1898
Soil faunal activity can be a major control of greenhouse gas (GHG) emissions from soil. Effects of single faunal species, genera or families have been investigated, but it is unknown how soil fauna diversity may influence emissions of both carbon dioxide (CO2, end product of decomposition of organic matter) and nitrous oxide (N2O, an intermediate product of N transformation processes, in particular denitrification). Here, we studied how CO2 and N2O emissions are affected by species and species mixtures of up to eight species of detritivorous/fungivorous soil fauna from four different taxonomic groups (earthworms, potworms, mites, springtails) using a microcosm set‐up. We found that higher species richness and increased functional dissimilarity of species mixtures led to increased faunal‐induced CO2 emission (up to 10%), but decreased N2O emission (up to 62%). Large ecosystem engineers such as earthworms were key drivers of both CO2 and N2O emissions. Interestingly, increased biodiversity of other soil fauna in the presence of earthworms decreased faunal‐induced N2O emission despite enhanced C cycling. We conclude that higher soil fauna functional diversity enhanced the intensity of belowground processes, leading to more complete litter decomposition and increased CO2 emission, but concurrently also resulting in more complete denitrification and reduced N2O emission. Our results suggest that increased soil fauna species diversity has the potential to mitigate emissions of N2O from soil ecosystems. Given the loss of soil biodiversity in managed soils, our findings call for adoption of management practices that enhance soil biodiversity and stimulate a functionally diverse faunal community to reduce N2O emissions from managed soils. 相似文献
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Parisa Farrokh Mojgan Sheikhpour Alibakhsh Kasaeian Hassan Asadi Roya Bavandi 《Biotechnology progress》2019,35(5):e2835
Cyanobacteria are photosynthetic microorganisms which can be found in various environmental habitats. These photosynthetic bacteria are considered as promising feedstock for the production of the third- and the fourth-generation biofuels. The main subject of this review is highlighting the significant aspects of the biofuel production from cyanobacteria. The most recent investigations about the extraction or separation of the bio-oil from cyanobacteria are also adduced in the present review. Moreover, the genetic engineering of cyanobacteria for improving biofuel production and the impact of bioinformatics studies on the designing better-engineered strains are mentioned. The large-scale biofuel production is challenging, so the economic considerations to provide inexpensive biofuels are also cited. It seems that the future of biofuels is strongly dependent to the following items; understanding the metabolic pathways of the cyanobacterial species, progression in the construction of the engineered cyanobacteria, and inexpensive large-scale cultivation of them. 相似文献
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Imen Saadaoui Touria Bounnit Maryam Muraikhi Rihab Rasheed Ghamza Alghasal Hareb Al Jabri 《Phycological Research》2018,66(3):182-188
Microalgae are considered a very promising alternative for biofuel production. Several strategies were developed to modulate and improve algae metabolites production to meet the requirements for biodiesel production. Most previous research evidenced that the increase of the lipid content is accompanied by a decrease of the biomass production, which increases the cost of the downstream processing. Hence, the challenge is to find special culture conditions that increase the lipid and the biomass productivities simultaneously. In the present work, we developed a strategy for the improvement of biomass and lipid productivities in a novel local microalga isolate, Chlorocystis sp. QUCCCM14, which was not previously known as a promising strain. Indeed, culturing QUCCCM14 using f/2 medium with 10× NaH2PO4 (0.15 g L?1 NaNO3 and 5.6 mg L?1 NaH2PO4) resulted in an improvement of 3.178 folds the lipid productivity reaching 56.121 mg L?1 day?1 and enhanced the biomass productivity reaching 141.363 mg L?1 day?1, simultaneously. Comparative analyses of the FAME profiles demonstrated that fed‐batch culture with phosphate or nitrate separately leads to a high production of the omega 3 fatty acids (Linolenic acid), whereas fed‐batch culture with phosphate and nitrate simultaneously increased the production of fatty acids suitable for biodiesel production. 相似文献
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Jeffrey E. Stenzel Kristina J. Bartowitz Melannie D. Hartman James A. Lutz Crystal A. Kolden Alistair M. S. Smith Beverly E. Law Mark E. Swanson Andrew J. Larson William J. Parton Tara W. Hudiburg 《Global Change Biology》2019,25(11):3985-3994
Wildfire is an essential earth‐system process, impacting ecosystem processes and the carbon cycle. Forest fires are becoming more frequent and severe, yet gaps exist in the modeling of fire on vegetation and carbon dynamics. Strategies for reducing carbon dioxide (CO2) emissions from wildfires include increasing tree harvest, largely based on the public assumption that fires burn live forests to the ground, despite observations indicating that less than 5% of mature tree biomass is actually consumed. This misconception is also reflected though excessive combustion of live trees in models. Here, we show that regional emissions estimates using widely implemented combustion coefficients are 59%–83% higher than emissions based on field observations. Using unique field datasets from before and after wildfires and an improved ecosystem model, we provide strong evidence that these large overestimates can be reduced by using realistic biomass combustion factors and by accurately quantifying biomass in standing dead trees that decompose over decades to centuries after fire (“snags”). Most model development focuses on area burned; our results reveal that accurately representing combustion is also essential for quantifying fire impacts on ecosystems. Using our improvements, we find that western US forest fires have emitted 851 ± 228 Tg CO2 (~half of alternative estimates) over the last 17 years, which is minor compared to 16,200 Tg CO2 from fossil fuels across the region. 相似文献
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A high coefficient of variation is characteristic of the bioelectric potentials recorded from living long bones. As a consequence, the data collected from animal and human experiments are difficult to use in practical ways. A distribution curve for bone bioelectric potentials has been calculated using polynomial regression analysis to process the voltage values recorded on the whole length of rabbit tibiae, with reference electrodes positioned in three different points of the bone. The distribution curve so obtained is presented to fulfill the need for a reference curve for the bioelectric potentials recorded from rabbit tibial surfaces. 相似文献
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The cellulose synthase (CESA) membrane complex synthesizes microfibrils of cellulose that surround all plant cells. Cellulose is made of sugar (β,1‐4 glucan) and accessing the sugar in cellulose for biofuels is of critical importance to stem the use of fossil fuels and avoid competition with food crops and pristine lands associated with starch‐based biofuel production. The recalcitrance of cellulose to enzymatic conversion to a fermentable form of sugar is related to the degree of hydrogen bonding or crystallization of the glucan chain. Herein, we isolate the first viable low biomass‐crystallinity mutant by screening for altered cell wall structure using X‐ray scattering as well as screening for enzymatic conversion efficiency on a range of cell wall mutants in the model plant Arabidopsis thaliana (L.) Heynh. Through detailed analysis of the kinetics of bioconversion we identified a mutant that met both selection criteria. This mutant is ixr1‐2, which contains a mutation in a highly conserved consensus sequence among the C‐terminal transmembrane regions within CESA3. A 34% lower biomass crystallization index and 151% improvement in the efficiency of conversion from raw biomass to fermentable sugars was measured relative to that of wild type (Col‐0). Recognizing the inherent ambiguities with an insoluble complex substrate like cellulose and how little is still understood regarding the regulation of CESA we propose a general model for how to manipulate CESA enzymes to improve the recalcitrance of cellulose to enzymatic hydrolysis. This study also raises intriguing possibilities as to the functional importance of transmembrane anchoring in CESA complex and microfibril formation. 相似文献
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Microalgae biofuel production can be feasible when a second function is added, such as wastewater treatment. Microalgae differ in uptake of phosphorus (P) and growth, making top performer identification fundamental. The objective of this screen was to identify dual‐purpose candidates capable of high rates of P removal and growth. Three freshwater – Chlorella sp., Monoraphidium minutum sp., and Scenedesmus sp. – and three marine – Nannochloropsis sp., N. limnetica sp., and Tetraselmis suecica sp. – species were batch cultured in 250 mL flasks over 16 days to quantitate total phosphorus (TP) removal and growth as a function of P loads (control, and 5, 10, and 15 mg L?1 enrichment of control). Experimental design used 100 μmol m?2 s?1 of light, a light/dark cycle of 14/10 h, and no CO2 enrichment. Phosphorus uptake was dependent on species, duration of exposure, and treatment, with significant interaction effects. Growth was dependant on species and treatment. Not all species showed increased P removal with increasing P addition, and no species demonstrated higher growth. Nannochloropsis sp and N. limnetica sp. performed poorly across all treatments. Two dual‐purpose candidates were identified. At the 10 mg L?1 treatment Monoraphidium minutum sp. removed 67.1% (6.66 mg L?1 ± 0.60 SE) of TP at day 8, 79.3% (7.86 mg L?1 ± 0.28 SE) at day 16, and biomass accumulation of 0.63 g L?1 ± 0.06 SE at day 16. At the same treatment Tetraselmis suecica sp. removed 79.4% (6.98 mg L?1 ± 0.24 SE) TP at day 8, 83.0% (7.30 mg L?1 ± 0.60 SE) at day 16, and biomass of 0.55 g L?1 ± 0.02 SE at day 16. These species merit further study using high‐density wastewater cultures and lipid profiling to assess suitability for a nutrient removal and biomass/biofuel production scheme. 相似文献