| 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. |
- Hagelin, Christina, 1977, et al.
(författare)
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A polarized-light spectroscopy study of interactions of a hairpin polyamide with DNA
- 2006
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Ingår i: Biophysical Journal. - : Elsevier BV. - 0006-3495 .- 1542-0086. ; 91:3, s. 904-911
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Tidskriftsartikel (refereegranskat)abstract
- We here study the interactions of a polyamide with large DNA, and compare to those of minor groove binder distamycin (DST), including high ligand/DNA binding ratios. Specific as well as nonspecific binding is probed using polarized-light spectroscopy combined with singular value decomposition analysis. Circular and linear dichroism data confirm binding geometries consistent with minor groove binding for both of the ligands. Interestingly, at high and intermediate ligand/DNA ratios the polyamide exhibits no significant sequence discrimination between mixed-sequence (calf thymus) and AT DNA as compared to DST. Each ligand is concluded to exhibit two different binding modes depending upon ligand/DNA ratio and nucleo-base sequence. At high binding ratios, distinct differences between the ligands are observed: circular dichroism spectra exciton effects provide evidence of bimolecular interactions of the polyamide when bound to AT-DNA, whereas no effects are seen with DST or mixed-sequence DNA. Also linear dichroism indicates that a change in binding geometry occurs at high polyamide/AT ratios, and that the effect occurs only with polyamide in contrast to DST. Since the effect is insignificant with DST, or with calf thymus DNA, it is concluded that it relates to the sizes of the ligands and the minor grooves, becoming critical in the limit of crowding.
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| 3. |
- 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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| 4. |
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| 5. |
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| 6. |
- Kalinowski, Birgitta E., et al.
(författare)
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Microbial mobilization of uranium from shale mine waste
- 2006
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Ingår i: Geomicrobiology Journal. - : Informa UK Limited. - 0149-0451 .- 1521-0529. ; 23:3-4, s. 157-164
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Tidskriftsartikel (refereegranskat)abstract
- The alum shale in the Billingen area in southern Sweden was mined in Ranstad for 5 years during the 1960s. The crushed tailings (processed and unprocessed) were left behind when the Ranstad mine was closed that has caused leaching of metals to the surroundings. The siderophore producing bacterium Pseudomonas fluorescens (sp, SE Sweden) was grown in batch cultures for 5 to 8 days with naturally weathered (unprocessed) uranium ore (0.0029% U by weight), kolm (0.52% U by weight) and acid-leached ore (0.0099% U by weight) in chemically defined media (unbuffered and buffered). Pseudomonas fluorescens grown with ore and unbuffered medium changed the pH from 4.7 to 9.3 and leached out 0.016 to 0.9% (normalized to surface area) of the total amount of U from the different ores. Incubation of the acid-leached ore with bacteria in buffered medium leached out 0.04% of the total U. Uranium was leached out selectively at all conditions, but this could be a pH effect, as pH increased at the same time as the U concentrations did. The observed release of Fe was most likely attributed to the production of microbial siderophores (Fe3+ specific chelators) since Fe3+ has a low solubility at pH > 4. As siderophores contain a number of chelating groups they may still function as complexators even in partly degraded form also for other metals than Fe. Thus, the production of microbial chelators could contribute to the elevated metal concentrations in the drainage water from the closed Ranstad mine, as abiotic processes cannot fully explain these high metal concentrations. In the extension: ligand promoted leaching of toxic elements could also be the key to bioremediation as there is a need for nontoxic cleanup methods for metal contaminated sites.
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| 7. |
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| 8. |
- 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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| 9. |
- 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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| 10. |
- 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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