| 1. |
- Berndes, Göran, 1966, et al.
(author)
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The contribution of biomass in the future global energy supply: A review of 17 studies
- 2003
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In: Biomass and Bioenergy. - 1873-2909 .- 0961-9534. ; 25:1, s. 1-28
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Journal article (peer-reviewed)abstract
- This paper discusses the contribution of biomass in the future global energy supply. The discussion is based on a review of 17 earlier studies on the subject. These studies have arrived at widely different conclusions about the possible contribution of biomass in the future global energy supply (e.g., from below 100 EJ yr-1 to above 400 EJ yr-1 in 2050). The major reason for the differences is that the two most crucial parameters - land availability and yield levels in energy crop production - are very uncertain, and subject to widely different opinions (e.g., the assessed 2050 plantation supply ranges from below 50 EJ yr-1 to almost 240 EJ yr-1). However, also the expectations about future availability of forest wood and of residues from agriculture and forestry vary substantially among the studies. The question how an expanding bioenergy sector would interact with other land uses, such as food production, biodiversity, soil and nature conservation, and carbon sequestration has been insufficiently analyzed in the studies. It is therefore difficult to establish to what extent bioenergy is an attractive option for climate change mitigation in the energy sector. A refined modeling of interactions between different uses and bioenergy, food and materials production - i.e., of competition for resources, and of synergies between different uses - would facilitate an improved understanding of the prospects for large-scale bioenergy and of future land-use and biomass management in general. © 2003 Elsevier Science Ltd. All rights reserved.
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| 2. |
- Berndes, Göran, 1966, et al.
(author)
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The feasibility of large-scale lignocellulose-based bioenergy production
- 2001
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In: Biomass and Bioenergy. - 1873-2909 .- 0961-9534. ; 20:5, s. 371-383
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Journal article (peer-reviewed)abstract
- Global, large-scale use of bioenergy may replace a significant part of present fossil fuel use. We show that labor availability and water resources are large compared to those required to operate a bioenergy system of such size. The present study contradicts the assertion by Giampietro et al. [Bioscience 47(9) (1997) 587], that labor and water availability provide invincible barriers to a large-scale use of biofuels. We examine water and labor requirements under more reasonable assumptions about bioenergy supply options and demand levels. Bioenergy supplies are based on dedicated plantations of lignocellulosic crops and bioenergy demand is based on the renewable intensive global energy scenarios (RIGES). We find that labor and water requirements are an order of magnitude lower than the estimates by Giampietro et al. For instance, labor requirements do not exceed 1 percent of the estimated total work force in any country. © 2001 Elsevier Science Ltd.
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| 3. |
- Hansson, P.A., et al.
(author)
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Air emissions from the fuel supply system of a Swedish CHP plant and the effects of stricter emission regulations
- 2003
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In: Biomass and Bioenergy. - 1873-2909 .- 0961-9534. ; 24:1, s. 59-68
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Journal article (peer-reviewed)abstract
- The purpose of this work was to quantify the energy use and production of air emissions by supply systems for different biofuels used in a typical Swedish combined heat and power plant. In addition, the effects of the future reductions in the total amounts of exhaust gas emissions, as a result of stricter emission regulations for transport and off-road equipment, were studied. A model was developed and used for the calculations. Input data were collected from a plant situated some 100 km from Stockholm in Sweden. Biofuels used by the plant include chips from limbs and tops, by-products from sawmills and chips from willow energy plantations. The results show that residues from sawmills are very favourable in terms of the studied environmental parameters. Air emissions from limbs and tops is 5-8 times greater than that from sawmills. The use of a terminal for temporary storage means that additional transport and loading operations are necessary which result in a 30% increase in air emissions. The most important effects of the stricter emission regulations are that emissions of nitrous oxides (NOx) caused by the supply system will decrease by up to 70% within 10 years and that the unburned hydrocarbon (HC) emissions will decrease by 30-35%. © 2002 Elsevier Science Ltd. All rights reserved.
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| 4. |
- Alamia, Alberto, 1984, et al.
(author)
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Design of an integrated dryer and conveyor belt for woody biofuels
- 2015
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In: Biomass and Bioenergy. - : Elsevier BV. - 1873-2909 .- 0961-9534. ; 77, s. 92-109
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Journal article (peer-reviewed)abstract
- Combustion or gasification of high-moisture content biomass is associated with a number of drawbacks, such as operational instabilities and lowered total efficiency. The present work proposes an integrated dryer and conveyor belt for woody biofuels with steam as the heat transfer medium. The use of low-temperature steam is favorable from a heat management point of view, but also helps to minimize the risk of fire, self-ignition and dust explosions. Furthermore, the presented dryer design represents an efficient combination of fuel transport, drying equipment and fuel feeding system.The proposed design is developed from a macroscopic energy and mass balance model that uses results from computational fluid dynamics (CFD) fuel bed modeling and experiments as its input. This CFD simulation setup can be further used to optimize the design with respect to bed height, steam injection temperatures and fuel type. The macroscopic model can be used to investigate the integration of the dryer within a larger biomass plant. Such a case study is also presented, where the dryer is tailored for integration within an indirect steam gasification system. It is found that the exergy efficiency of this dryer is 52.9%, which is considerably higher than those of other dryers using air or steam, making the proposed drying technology a very competitive choice for operation with indirect steam gasification units.
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| 5. |
- Anasontzis, George E, 1980, et al.
(author)
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Rice straw hydrolysis using secretomes from novel fungal isolates from Vietnam
- 2017
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In: Biomass and Bioenergy. - : Elsevier BV. - 1873-2909 .- 0961-9534. ; 99, s. 11-20
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Journal article (peer-reviewed)abstract
- With a production of 39 million metric tons each year, rice is one of the main agricultural products of Vietnam. Thus, rice straw is a significant by-product, whose use in a biorefinery process would contribute to the bio-based transformation of the Vietnamese and South East Asian economy. In order to find novel efficient enzyme mixtures for the hydrolysis of rice straw and other agricultural residues, we took advantage of the rapidly evolving biodiversity of Vietnam and screened 1100 new fungal isolates from soil and decaying plant tissues for their CMCase activity. We selected 36 strains and evaluated them for their cellulases, xylanases, and accessory enzymes activities. Most of these isolates belonged to the genera Aspergillus and Trichoderma. We identified a few promising isolates, such as A. brunneoviolaceus FEC 156, A. niger FEC 130 and FEC 705, and A. tubingensis FEC 98, FEC 110 and FEC 644, whose produced enzyme mixtures released a mass fraction of the sugar content of alkali-treated rice straw higher than 20%, compared to 10% for Trichoderma reesei RUT C-30. We verified that the black Aspergilli are particularly efficient in their saccharification ability. We also identified strains that although they produced low amounts of cellulases and xylanases, their enzyme mixtures had high saccharification efficiencies, indicating the importance of the synergy effect, rather than the amount of enzymes available. Our results highlight the intra-species variation, especially in the Trichoderma genus, regarding the biomass degradation characteristics and the associated range of enzymatic activities.
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| 6. |
- Andersson, Viktor, 1983, et al.
(author)
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Algae-based biofuel production as part of an industrial cluster
- 2014
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In: Biomass and Bioenergy. - : Elsevier BV. - 1873-2909 .- 0961-9534. ; 71, s. 113-124
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Journal article (peer-reviewed)abstract
- This paper presents a study on the production of biofuels from algae cultivated in municipal wastewater in Gothenburg, Sweden. A possible biorefinery concept is studied based on two cases; Case A) combined biodiesel and biogas production, and Case B) only biogas production. The cases are compared in terms of product outputs and impact on global CO2 emissions mitigation. The area efficiency of the algae-based biofuels is also compared with other biofuel production routes. The study investigates the collaboration between an algae cultivation, biofuel production processes, a wastewater treatment plant and an industrial cluster for the purpose of utilizing material flows and industrial excess heat between the actors. This collaboration provides the opportunity to reduce the CO2 emissions from the process compared to a stand-alone operation. The results show that Case A is advantageous to Case B with respect to all studied factors. It is found that the algae-based biofuel production routes investigated in this study has higher area efficiency than other biofuel production routes. The amount of algae-based biofuel possible to produce corresponds to 31 MWfuel for Case A and 26 MWfuel in Case B.
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| 7. |
- Baena-Moreno, Francisco, 1992, et al.
(author)
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Biogas upgrading through calcium looping: Experimental validation and study of CO 2 capture
- 2023
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In: Biomass and Bioenergy. - 1873-2909 .- 0961-9534. ; 176
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Journal article (peer-reviewed)abstract
- The calcium looping technology is one of the most promising technologies for capturing and storing CO2. This technology has been evaluated with a variety of sorbents and conditions in previous works, but the inlet CO2-ladden gas has typically been a flue gas from combustion, which typically has a composition of 10–20% CO2 and 80–90% N2. On the other side, the performance of the calcium looping process for CO2 capture of other gases (i.e., biogas or gases resulting from hydrothermal carbonization) remains largely unstudied. In this work, this knowledge gap is assessed through evaluating the performance of the calcium looping process for biogas (synthesized as 40% CO2, 60% CH4) in terms of carbonation conversion. This experimental study investigates the impact of: (1) using an inlet gas composition representative for biogas instead of combustion flue gas; (2) different biogas compositions; (3) the carbonation temperature; (4) the cooling-down and heating-up of the sorbent material between the reactor and ambient temperatures within cycles; (5) the atmosphere composition during calcination; and (6) the solids particle size. The main result obtained is that the overall CO2-capture performance of calcium looping improves when using biogas as inlet CO2-ladden gas, in comparison with combustion flue gas. One main contribution to this improved performance is shown to be the presence of secondary reactions (i.e., dry reforming, methanation). The impact of the CH4 to CO2 ratio tested is not remarkable, showing that the potentialities of the process in this aspect can be adapted to several biogas producing feedstocks.
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| 8. |
- Berggren, Mårten, et al.
(author)
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Biomass co-firing potentials for electricity generation in Poland—Matching supply and co-firing opportunities
- 2008
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In: Biomass and Bioenergy. - : Elsevier BV. - 1873-2909 .- 0961-9534. ; 32:9, s. 865-879
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Journal article (peer-reviewed)abstract
- As part of the European Union (EU) accession treaty, Poland is obliged to increase the share of renewable electricity production to 7.5% by 2010 (from a present share of about 2% in 2002). Most of this increase is expected to be covered by biomass-based electricity generation. This paper investigates the potential for co-firing of biomass and coal in the Polish power-generation system. More specifically, this study focuses on matching potentials in biomass supply with opportunities for co-firing biomass in existing coal-fired power plants. Available estimates of biomass supply and information on the power plant infrastructure are used as input for modelling the co-firing potential for each of the 16 regions in Poland ("Voivodship"). The modelling also gives the additional cost of the electricity and the CO2-avoidance cost for the co-firing. The result shows a potential of electricity produced from biomass in co-firing of 1.6-4.6% (2.3-6.6 TWhe) of the total electricity production in 2010. Adding this potential to the existing production of about 2% electricity from renewable energy sources (RES-E) gives an overall contribution of RES-E in the range 3.6-6.6%. The additional cost for the implementation of co-firing is less than €20 per MWhe (the average electricity price in Poland in 2003 was €96 per MWhe) corresponding to a CO2-avoidance cost of less than €20 per tonne CO2. In summary it can be concluded that although co-firing can serve as a low-cost option for near-term increase of RES-E, there is still an additional 0.9-3.9% of other RES-E production required to be developed to reach the 2010 target of 7.5% RES-E. The results call for quick action with respect to implementation of co-firing, if Poland should have any chance to reach the RES-E target by 2010.
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| 9. |
- Berndes, Göran, 1966, et al.
(author)
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Strategies For 2nd Generation Biofuels In Eu - Co-firing to stimulate feedstock supply development and process integration to improve energy efficiency and economic competitiveness
- 2010
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In: Biomass and Bioenergy. - : Elsevier BV. - 1873-2909 .- 0961-9534. ; 34:2, s. 227-236
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Journal article (peer-reviewed)abstract
- The present biofuel policies in the European Union primarily stimulate 1st generation biofuels that are produced based on conventional food crops. They may be a distraction fromlignocellulose based 2nd generation biofuels – and also from biomass use for heat and electricity – by keeping farmers’ attention and significant investments focusing on firstgeneration biofuels and the cultivation of conventional food crops as feedstocks. This article presents two strategies that can contribute to the development of 2nd generation biofuels based on lignocellulosic feedstocks. The integration of gasification-based biofuel plants in district heating systems is one option for increasing the energy efficiency and improving the economic competitiveness of such biofuels. Another option, biomass co-firing with coal,generates high-efficiency biomass electricity and reduces CO2 emissions by replacing coal. It also offers a near-term market for lignocellulosic biomass, which can stimulate development of supply systems for biomass also suitable as feedstock for 2nd generation biofuels. Regardless of the long-term priorities of biomass use for energy, the stimulation of lignocellulosic biomass production by development of near term and cost-effective markets isjudged to be a no-regrets strategy for Europe. Strategies that induce a relevant development and exploit existing energy infrastructures in order to reduce risk and reach lower costs, are proposed an attractive complement the present and prospective biofuel policies.
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| 10. |
- Bäfver, Linda S, 1975, et al.
(author)
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Particle emissions from pellets stoves and modern and old-type wood stoves
- 2011
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In: Biomass and Bioenergy. - : Elsevier BV. - 1873-2909 .- 0961-9534. ; 35:8, s. 3 6 4 8-3 6 5 5
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Journal article (peer-reviewed)abstract
- The purpose of this work is to characterise particle emissions from pellets stoves and modern and old-type residential wood stoves. The mass concentration of particulate material in the hot flue gas was 19e82 mg/MJ, roughly the same for wood stoves and pellets stoves, but the old-type wood stoves tended to emit even higher quantities. Furthermore, during combustion of wood logs the considerably higher emission of organic gaseous carbon indicates an additional contribution to the emission from secondarily formed condensable organic particles.The particle mass emitted was dominated by fine particles (
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