| 1. |
- 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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| 2. |
- 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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| 3. |
- 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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| 4. |
- Nevalainen, H., et al.
(författare)
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Firing of coal and biomass and their mixtures in 50 kW and 12 MW circulating fluidized beds - Phenomenon study and comparison of scales
- 2007
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Ingår i: Fuel. - : Elsevier BV. - 0016-2361. ; 86:14, s. 2043-2051
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Tidskriftsartikel (refereegranskat)abstract
- The combustion dynamics of coal, wood chips and their mixture is investigated. Load change capability and the effect of the individual control variables, for example the mixture ratio of different fuels, on pilot-scale CFB boiler dynamics were also studied. Disturbances in fuel feeding cause fluctuations in the flue gas concentrations. Changes in the heating value are possible due to varying moisture content of the fuel. Both these disturbances affect the instantaneous firing rate in a boiler. Also the characteristics of the fuels have to be taken into consideration when designing boiler control systems. When co-firing two fuels with clearly distinct combustion characteristics, direct assumptions based on each fuel's characteristies cannot be made about combustion behaviour of their mixture. Combustion experiments with coal and wood chips and their co-firing were carried out in a pilot-scale CFB reactor (VTT) and a large-scale CFB boiler (Chalmers). A comparison of the combustion in the two different size reactors, provides information about scaling. The combustion responses due to changes in the fuel feeding of the two circulating fluidized beds are analyzed by a dynamic model. (c) 2007 Elsevier Ltd. All rights reserved.
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| 5. |
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| 6. |
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| 7. |
- Almendros-Ibáñez, J. A., et al.
(författare)
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Voidage distribution around bubbles in a fluidized bed
- 2010
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Ingår i: Powder Technology. - : Elsevier BV. - 1873-328X .- 0032-5910. ; 197:1, s. 73-82
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Tidskriftsartikel (refereegranskat)abstract
- n this work, a new method for measuring void fraction distribution around endogenous bubbles in a 2D fluidized bed is presented. The technique is based on illuminating a transparent-wall 2-dimensional bed with diffuse light from the rear and recording the distribution of light that penetrates the bed. The recording is made with a high speed video-camera, which gives frames with grey level corresponding to the light penetration and from which the voidage distribution around the bubbles can be determined. In this way, voidage distribution in the region very close to the bubble contour (r/Rb less, approximate 1.2) is obtained, which was not possible in previous studies due to limitations in spatial resolution. A correlation is proposed for the voidage at the contour of the bubble, with the voidage depending on the radial position and the polar angle.In addition, the effect of the voidage distribution on the throughflow crossing the bubbles was studied and an increase of 20% was determined for the average bubble geometry of the more than 100 bubbles analysed.
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| 8. |
- Häsä, H., et al.
(författare)
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Co-firing of coal and biomass in Circulating Fluidized Beds
- 2006
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Ingår i: 6th European Conference on Coal Research and its Applications.
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Konferensbidrag (refereegranskat)abstract
- To fulfil the development needs of OTSC CFB technology, a comprehensive understanding of CFB combustion processes needed to be achieved. Intensive research in laboratory, pilot and fullscale combustors is required to fulfil the abovementioned objectives.In order to study different process characteristics and verify measurements and simulations, experiments were carried out with different size reactors; VTT’s laboratory scale CFB reactor, VTT’s 50 kW pilot CFB reactor, Chalmers’ 12 MW CFB boiler, cold rig and with several commercial boilers.
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| 9. |
- Johansson, A., et al.
(författare)
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The performance of a loop seal in a CFB boiler
- 2006
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Ingår i: Journal of Energy Resources Technology, Transactions of the ASME. - : ASME International. - 1528-8994 .- 0195-0738. ; 128:2, s. 135-141
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Tidskriftsartikel (refereegranskat)abstract
- High in-bed heat transfer and low corrosive environment imply that the loop seal of a circulating fluidized bed (CFB) boiler is an advantageous location for superheaters. In order to increase the knowledge on the flow pattern and the heat transfer distribution to the tubes within a loop seal, measurements were performed in the loop seal of a 30 MW CFB boiler as well as in a 1/3 scaled-down seal operated according to simplified scaling laws. The scale model measurements show that the solids recirculation flux can be maintained with a substantial decrease of the fluidization flow in the seal compared to that currently used at full load conditions. It was also possible to significantly decrease the fraction of the bottom of the seal that was fluidized without affecting the solids flux through the seal. A gradient in the solids flow were detected in the vertical direction.
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| 10. |
- Johansson, P., et al.
(författare)
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Electricity dependency and CO2 emissions from heating in the Swedish building sector-Current trends in conflict with governmental policy?
- 2006
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Ingår i: Energy Policy. - : Elsevier BV. - 0301-4215. ; 34:17, s. 3049-3064
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Tidskriftsartikel (refereegranskat)abstract
- Coal-condensing power is marginal production in the deregulated Nordic power market and an increase in electricity consumption will therefore result in increased CO2 emissions. One goal of the Swedish energy policy is to reduce the amount of electricity used for heating in the building sector. This paper investigates the potential for reduction in electricity dependency and CO2 emissions from heating, taking the energy infrastructure into account, here defined as the capital stock of the buildings and heating systems together with geographical variations in heat intensity. In order to include the energy infrastructure in the analysis the study is made on a regional level (Southern Sweden) applying a comprehensive database describing the energy infrastructure of the region. The paper compares two scenarios for converting the heating systems of the region: one employing energy savings and with the aim to phase out the oil and most of the electricity used for heating purposes and a second which illustrates the effect if the current trend in the heating market continues. Both scenarios apply commercially available technologies only. From the second scenario it is seen that the current trend-contrary to the aim of the Swedish Governmental policy-shows an increase in electricity dependency for heating, mainly due to a large diffusion of heat pumps, but also due to installations of electrical floor heating and electricity heating systems installed in newly constructed one- and two-dwelling buildings. However, the options proposed in first scenario show that it is possible to reach significant reductions in the electricity dependency due to heating and in corresponding CO2 emissions. An analysis of the age structure of the heating systems shows that the transformation of the heating system is not completed until the year 2025, if new investments for replacement of heating systems are made only provided they have reached their economical life time, and only applying heating technologies which at present are known to be economically competitive. It can be concluded that future policies on transforming the energy system should be based on an analysis that takes the entire energy infrastructure (in this case of heating system) into account (e.g. not directed towards single technologies). More specifically for the region studied, which is considered representative for Sweden as a whole, policies should aim at installing heat pumps to replace electricity heating only in regions with low heat density where district heating is not competitive, in contrary to the present situation where heat pumps replace all types of heating systems.
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