| 1. |
- Cowie, A. L., et al.
(författare)
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Applying a science-based systems perspective to dispel misconceptions about climate effects of forest bioenergy
- 2021
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Ingår i: Global Change Biology Bioenergy. - : John Wiley and Sons Inc. - 1757-1693 .- 1757-1707. ; 13:8, s. 1210-1231
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Tidskriftsartikel (refereegranskat)abstract
- The scientific literature contains contrasting findings about the climate effects of forest bioenergy, partly due to the wide diversity of bioenergy systems and associated contexts, but also due to differences in assessment methods. The climate effects of bioenergy must be accurately assessed to inform policy-making, but the complexity of bioenergy systems and associated land, industry and energy systems raises challenges for assessment. We examine misconceptions about climate effects of forest bioenergy and discuss important considerations in assessing these effects and devising measures to incentivize sustainable bioenergy as a component of climate policy. The temporal and spatial system boundary and the reference (counterfactual) scenarios are key methodology choices that strongly influence results. Focussing on carbon balances of individual forest stands and comparing emissions at the point of combustion neglect system-level interactions that influence the climate effects of forest bioenergy. We highlight the need for a systems approach, in assessing options and developing policy for forest bioenergy that: (1) considers the whole life cycle of bioenergy systems, including effects of the associated forest management and harvesting on landscape carbon balances; (2) identifies how forest bioenergy can best be deployed to support energy system transformation required to achieve climate goals; and (3) incentivizes those forest bioenergy systems that augment the mitigation value of the forest sector as a whole. Emphasis on short-term emissions reduction targets can lead to decisions that make medium- to long-term climate goals more difficult to achieve. The most important climate change mitigation measure is the transformation of energy, industry and transport systems so that fossil carbon remains underground. Narrow perspectives obscure the significant role that bioenergy can play by displacing fossil fuels now, and supporting energy system transition. Greater transparency and consistency is needed in greenhouse gas reporting and accounting related to bioenergy.
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| 2. |
- Haugen, H.A., et al.
(författare)
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Infrastructure for CCS in the Skagerrak/Kattegat region, Southern Scandinavia: A feasibility study
- 2013
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Ingår i: Energy Procedia. - : Elsevier BV. - 1876-6102. ; 37, s. 2562-2569
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Konferensbidrag (refereegranskat)abstract
- This paper gives an overview of results from a project which explored the feasibility of establishing a CO2 Capture and Storage infrastructure in the Skagerrak/Kattegat region of Southern Scandinavia. This involves assessment of the technical and economic parameters of the complete CCS chain and, in particular, identification of possible storage locations. The project ran from June 2009 to December 2011. Emissions from three major industrial clusters in the Skagerrak/Kattegat region - Gothenburg in Sweden, Grenland in Telemark County, southern Norway and Aalborg in Denmark - were targeted. Both emissions from process industries as well as power plants were included.
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| 5. |
- Kjärstad, Jan, 1956, et al.
(författare)
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Modelling large-scale CCS development in Europe linking technoeconomic modelling to transport infrastructure
- 2013
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Ingår i: Energy Procedia. - : Elsevier BV. - 1876-6102. ; 37, s. 2941-2948
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Konferensbidrag (refereegranskat)abstract
- This paper a studies the potential lay-out of CCS infrastructure in Europe, by combining techno-economic modelling of Europs's electricity sector with a detailed modelling and analysis of a CO2 transport infrastructure. First, the electricity sector is described using the Chalmers Electricity Investment Model, which, for each EU member state, yields the technology mix including CCS - until the year 2050. The model gives the lowest system cost under a given CO2 emission reduction target. Thus, the model gives the annual flows of CO2 being captured by country and fuel. Secondly, these flows are used as input to InfraCCS, a cost optimization tool for bulk CO2 pipelines. Finally, the results from InfraCCS are applied along with Chalmers databases on power plants and CO2 storage sites to design the development over time of a detailed CO2 transport network across Europe considering the spatial distribution of power plants and storage locations. Two scenarios are studied: with and without onshore aquifer storage. The work shows that the spatial distribution of capture plants over time along with individual reservoir storage capacity and injectivity are key factors determining routing and timing of the pipeline network. The results of this work imply that uncertainties in timing for installation of capture equipment in combination with uncertainties related to accurate data on storage capacity and injectivity on reservoir level risk to seriously limit the build-up of large-scale pan-European CO2 transportation networks. The study gives that transport cost will more than double if aquifer storage is restricted to offshore reservoirs. Thus, it is found that the total investments for the pan-European pipeline system is € 31 billion.when storage in onshore aquifers is allowed and € 72 billion. if aquifer storage is restricted to offshore reservoirs with corresponding specific cost of € 5.1 to € 12.2 CO2 transported.
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| 6. |
- Köhler, Anna, 1989, et al.
(författare)
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Modeling the motion of fuel particles in a fluidized bed
- 2021
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Ingår i: Fuel. - : Elsevier BV. - 0016-2361. ; 305
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Tidskriftsartikel (refereegranskat)abstract
- A semiempirical model for the mixing of fuel particles in a fluidized bed is presented and validated against experimental data from the literature regarding lateral fuel mixing. The model of fuel particle mixing categorizes the fluidized bed into three mixing zones: a rising bubble wake solid zone, an emulsion zone with sinking bulk solids, and a splash zone located above the dense bed. In the emulsion zone, the axial motion of the fuel particle is described by a force balance, applying a viscoplastic stress model, i.e., with a dominant yield stress and only a minor contribution of the shear stress, using an empirical expression from the literature. In the lateral direction, the model is divided into so-called ‘recirculation cells’, which are crucial for the lateral mixing. Comparisons of the modeled and measured lateral dispersion coefficients of different fuel types measured in three different large-scale fluidized bed units under both hot and cold conditions (covering a broad range of coefficients: 10−4–10−1 m2/s) reveal satisfactory agreement. The validated model was used to investigate how the lateral mixing of fuel particles depends on the excess gas velocity, the bed height, and the lateral distribution of bubbles over the bed cross-section (which is typically uneven in industrial FB furnaces), as well as the size and density of the fuel particles.
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| 7. |
- Linderholm, Carl Johan, 1976, et al.
(författare)
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1st International Conference on Negative CO2 Emissions - Summary and Highlights
- 2018
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Ingår i: GHGT 2018 - 14th International Conference on Greenhouse Gas Control Technologies. - : International Energy Agency Greenhouse Gas, IEAGHG.
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Konferensbidrag (refereegranskat)abstract
- Negative CO2 emissions technologies include a number of technologies and biospheric storage options, the objective of which is the removal of atmospheric CO2 and thus the limitation of future global warming. An international conference on negative emissions technologies was conceived to meet the need for a broader understanding of the possibilities and challenges facing these technologies. The International Conference on Negative CO2 Emissions was held in May 22-24, 2018, at Chalmers University of Technology, Gothenburg, Sweden. The conference was organized by Chalmers with support from the Global Carbon Project, the City of Gothenburg, Nordic Energy Research, ECOERA, the Center for Carbon Removal, Göteborg Energi, Stockholm Exergi, and the International Energy Agency, i.e. IEAGHG, IEAIETS and IEA Bioenergy. The purpose of the conference was to bring together a wide range of scientific and technological disciplines and stakeholders, in order to engage in various aspects of research relating to negative CO2 emissions. This included various negative emission technologies, socio-economic and climate modelling, and climate policies and incentives. The conference was a major scientific event and the first in a conference series. The next conference will be held in the spring of 2020. This paper reports highlights and important messages from the conference.
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| 8. |
- Mazzetti, M.J., et al.
(författare)
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NORDICCS CCS roadmap
- 2014
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Ingår i: Energy Procedia. - : Elsevier BV. - 1876-6102. ; 51, s. 1-13
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Konferensbidrag (refereegranskat)abstract
- The Nordic CCS roadmap is developed in the NORDICCS project, a collaborative research project between leading CCS research institutions in the five Nordic countries. The roadmap will outline jointly developed Nordic strategies for widespread implementation of CCS in the Nordic countries in order to help Nordic industries meet a carbon constrained future with a high price on carbon emissions. It will identify pathways and milestones for large-scale Nordic implementation of CCS resulting in beneficial economies of scale that will increase the likelihood of implementation. Several novel cases will be presented that reveal future Nordic opportunities, including industrial CCS where emitters have large point sources of CO2 localized in clusters, and natural gas sweetening with the potential for use of Enhanced Oil Recovery (EOR) to defray the costs. Recommendations will be made for actions relating to joint political work in the Nordic region for improving the framework conditions for CCS.
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| 10. |
- Wiesendorf, V, et al.
(författare)
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THE CFB BOILER IN GARDANNE - AN EXPERIMENTAL INVESTIGATION OF ITS BOTTOM ZONE
- 1999
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Ingår i: Proc. of the 15th International Conference on Fluidized Bed Combustion.
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Konferensbidrag (refereegranskat)abstract
- Different measurement techniques have been used to analyze the fluid dynamics in the bottom zone of the 250 MWe Circulating Fluidized Bed (CFB) boiler in Gardanne, France. In particular, horizontal profiles of the local solids volume concentration have been measured with a capacitance probe and the vertical pressure profile has been measured by a probe with densely spaced pressure taps. Local velocities were measured by cross-correlating the signals of a twochannel capacitance probe. In order to get some information on the influence of the flow structure on local combustion conditions a probe has been used which combines both capacitance and zirconia-cell sensors. This probe measured simultaneously local solids volume concentrations, local velocities and the local presence of oxygen. The results show the existence of a dense bed with a bed height of about 2% of the total riser height. This bottom bed has a flow structure which is different from the core-annulus structure observed in the upper dilute zone of the CFB combustor by several researchers (e.g. Berruti et al. (1995)). The lateral solids mixing does not seem to be enough to provide an even distribution of char over the whole cross-section of the bottom bed. Nevertheless, an even temperature distribution has been found indicating that mixing is sufficient to equalize the uneven heat generation.
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