| 41. |
- Andersson, Karin, 1952
(författare)
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The shipping industry and the climate
- 2022
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Ingår i: Sustainable Energy Systems on Ships: Novel Technologies for Low Carbon Shipping. - 9780128244715 ; , s. 3-25
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- As by 2020, the past six years, including 2020, are likely to be the six warmest years on record and the global mean temperature was 1.2°C above the preindustrial level [1]. International agreements, the Kyoto Protocol (1997) and the Paris agreement (2016), has set the aim to keep a global temperature rise during this century well below 2°C above pre-industrial levels. The anthropogenic inflow of GHGs to the atmosphere from the shipping industry was estimated by the IMO to totally around 2.5–3% of the global emissions in 2018 (or 1076 million tonnes). This is an increase by 9.6% since the previous study in 2014. The IMO projects the future emissions to increase from 1000 Mt CO2 in 2018 to 1000 to 1500 Mt CO2 in 2050 in a “Business as Usual”, BAU, scenario. Two years after the Paris agreement, the IMO adopted a vision, followed by a plan for implementation, in which a global goal of 50% reduction in GHG emissions from shipping by 2050 compared to 2008, and a total phase-out “within this century” is stated. Action from the IMO has started with a data collection system for fuel oil consumption. Ships of >5000 gross tonnage are required to collect consumption data fuel oil use and data on transport work. The European Union has started work on emission decrease with demands on Monitoring, Reporting and Verification of CO2 emissions from large ships (>5000 tonnes) using EU ports. Also here further measures are expected. At present here are many different initiatives, internationally, from countries as well as from shipping companies and shipowners to find ways towards “zero carbon shipping”. The different regulations and incentives introduced will help on the way, but still there is a need for more strict regulations or stronger incentives. The present initiatives give a large potential to make shipping and sea transport an important player also in a carbon neutral, sustainable society.
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| 42. |
- Jasinski, Michal, et al.
(författare)
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Operation and Planning of Energy Hubs Under Uncertainty - a Review of Mathematical Optimization Approaches
- 2023
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Ingår i: IEEE Access. - 2169-3536 .- 2169-3536. ; 11, s. 7208-7228
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Tidskriftsartikel (refereegranskat)abstract
- Co-designing energy systems across multiple energy carriers is increasingly attracting attention of researchers and policy makers, since it is a prominent means of increasing the overall efficiency of the energy sector. Special attention is attributed to the so-called energy hubs, i.e., clusters of energy communities featuring electricity, gas, heat, hydrogen, and also water generation and consumption facilities. Managing an energy hub entails dealing with multiple sources of uncertainty, such as renewable generation, energy demands, wholesale market prices, etc. Such uncertainties call for sophisticated decision-making techniques, with mathematical optimization being the predominant family of decision-making methods proposed in the literature of recent years. In this paper, we summarize, review, and categorize research studies that have applied mathematical optimization approaches towards making operational and planning decisions for energy hubs. Relevant methods include robust optimization, information gap decision theory, stochastic programming, and chance-constrained optimization. The results of the review indicate the increasing adoption of robust and, more recently, hybrid methods to deal with the multi-dimensional uncertainties of energy hubs.
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| 43. |
- Murekatete, Rachel Mundeli, 1981-
(författare)
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Sensitivity, Variation, and Application of Least-Cost Path Models in Landscape Connectivity Analysis and Corridor Planning
- 2022
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In recent decades, Rwanda has been affected by the loss and fragmentation of natural habitats for native species of animals and plants. As a consequence, landscape connectivity—i.e., the degree to which a landscape facilitates or impedes the movement of organisms between resource patches—has considerably weakened or is even completely lost, causing detrimental effects on biodiversity, notably the reduction of populations of key native species. In order to counter this problem, one potential solution currently being explored by local planners in Rwanda consists of establishing conservation corridors for organisms to move safely between their habitat remnants. Specifically, this thesis was inspired by a project initiated by the Dian Fossey Gorilla Fund International, a conservation non-governmental organization (NGO) based in Rwanda, which consists of establishing a conservation corridor for pollinators.For their capabilities of storing, processing, and visualizing landscape data, geographic information systems (GIS) have been increasingly popular among conservation biologists and practitioners. Of particular relevance to connectivity analysis and corridor planning is the least-cost path model. A typical use of this model is such that one first estimates the cost for a certain action (e.g., movement by an organism or acquisition by a government) at each location of a given landscape and represents the results in the form of a raster surface, and then measures the degrees of connectivity between patches of interest in terms of effective distances, which are equated with least-cost path distances over the raster cost surface. While the least-cost path model is easy to use and available in virtually any commercial raster-based GIS, we observe that users of it often overlook some important assumptions, the violation of which might greatly affect the validity of the model’s outcome.The goal of this thesis is to provide a scientific contribution to landscape connectivity analysis and conservation corridor planning by 1) investigating the potential misuse or abuse of the conventional least-cost path model when sufficient information is not available on the underlying cost surface, 2) proposing an alternative model under such a circumstance and 3) demonstrating its relevance to conservation practice. More specifically, for the model to work, it is explicitly or implicitly assumed that, the optimality of a path is evaluated as the sum of the cost-weighted lengths of all its segments—cost-weighted, i.e., multiplied by their underlying cost values. The validity of this assumption must be questioned, however, if cost values are measured on a scale—e.g., an ordinal scale of measurement in Stevens’s typology—that does not permit arithmetic operations. In a typical practice of landscape connectivity analysis and corridor planning, the raster cost surface is created by transforming one or more sets of values (e.g., land cover type, land ownership, and elevation) attributed to cells into another set of such values (representing cost) through a function reflecting one or more criteria. A question arises: how certain can one be about the correctness of such a cost estimation function?There are at least four issues in the application of the least-cost path model to landscape connectivity analysis and corridor planning under uncertainty. First, while it is generally anticipated that different cost estimation functions lead to different least-cost paths (hence to different effective distances or different corridor locations), little is known on how such differences arise (or do not arise). Second, while it is generally recognized that the location and length of a least-cost path are both sensitive to the spatial resolution of the raster cost surface, little is known if they are always sensitive in the same way and to the same degree and if not, what makes them more (or less) sensitive. Third, when it is difficult to establish a fully connected corridor between target habitat areas (e.g., because of surrounding anthropogenic activities), the least-cost path (which is by definition fully connected) may not be useful at least in its original form. Lastly, even if the conventional least-cost path model may have inconsistent results in theory, it may well be continued to be used in practice, unless there is a sound alternative to it.The issues raised above are addressed through four studies corresponding to four respective papers which are appended to this thesis. While the first three studies use artificial landscape data generated by computers with varying spatial and non-spatial characteristics, the fourth study uses data on a real landscape. The first study (Paper 1) evaluates how the locations and lengths of least-cost paths (the latter of which are referred to as least-cost distances) vary with change in cost estimation parameters. This is done through a series of computational experiments, in which each of the artificial landscapes is converted into different cost surfaces by systematically varying parameters of a cost-estimation function, on which least-cost paths are generated. The locations and lengths of those paths are statistically analyzed to find sources of their variation. The second study (Paper 2) investigates how the least-cost distance is affected by the spatial resolution of the corresponding cost surface. This is also done through a series of computational experiments, in which each of the artificial landscapes is converted into a cost surface, which is, in turn, converted into different cost surfaces (different, i.e., only in their spatial resolutions) by systematically aggregating grid cells. Then, the statistical behavior of the ratio of the least-cost distance measured on a lower-resolution cost surface to that measured on a higher-resolution cost surface is analyzed. The third study (Paper 3) proposes the mini-max path model as an alternative to the least-cost path model. Unlike the conventional model (in which the optimality of a path is based on the sum of its length multiplied by the underlying cost values), the alternative model determines the optimality of a path using the length of a segment(s) of the path that intersects the cells having the maximum cost value (with a special tie-breaking rule). The performances of the two models are tested in one of the following two assumptions at a time: the cost values are measured on an ordinal scale or on a ratio scale. The fourth study (Paper 4) applies the model proposed in the third study to an ongoing conservation project of the Dian Fossey Gorilla Fund International that plans to design a ‘stepping-stone’ corridor—which is not fully connected but takes the form of a sequence of fragmented forest patches—between two core habitat areas of pollinator birds between two protected areas in Rwanda. The project does not have complete information on the study area and the target species and thus the project staff can only rank land cover types in terms of their suitability/cost for being part of the corridor. The utility of the model is tested with different assumptions on the behavior of the birds (e.g., minimum stepping stone size) as well as on the cost associated with the implementation of the corridor (e.g., cost for planting shrubs along the corridor to encourage the birds to use it).The first study finds that the same pair of terminal cells may well be connected by different least-cost paths on different cost surfaces though derived from the same landscape data. The variation among those paths is highly sensitive to the forms of spatial and non-spatial distributions of landscape elements (which cannot be controlled by users of the least-cost path model) as well as by those of cost values derived from them (which may be, at least indirectly, controlled by users of the model). The second study finds that least-cost distances measured on lower-resolution cost surfaces are generally highly correlated with—and useful predictors of—effective distances measured on higher-resolution cost surfaces. This relationship tends to be weakened when linear barriers to connectivity (e.g., roads and rivers) exist, but strengthened as distances increase and/or when linear barriers (if any) are detected by other presumably more accessible and affordable sources such as vector line data. The third study confirms the effectiveness of the conventional least-cost path model on ratio-scaled cost surfaces but finds that the alternative mini-max path model is mathematically sounder if the cost values are measured on an ordinal scale and practically useful if the problem is concerned not with the minimization of cost but with the maximization of some desirable condition such as suitability. The fourth study demonstrates the utility of the mini-max path model by effectively casting the stepping stone corridor problem as a special case of it. The model allows for a rapid first delineation of candidate routes for stepping stone corridors and facilitates the early exploratory stages of conservation projects.Major implications of this thesis to the research and practice in landscape connectivity analysis and conservation corridor planning with raster-based GIS are summarized as follows.When sufficient information is available for quantification of cost values, the conventional least-cost path model is a reasonable approach to use.However, it is worth trying or at least acknowledging alternatives that do not rely on the quantitative-cost assumption if the value of each cell only indicates the ordinal category of cost of intersecting that cell. Note in particular that information used for cost estimation in practice (e.g., expert opinions or public surveys) are often of subjective and qualitative nature.The highest-resolution data may not always be most effective—much less, most cost-effective—for the task being undertaken. The choice of spatial resolution of th
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| 44. |
- Perera, Amarasinghage Tharindu Dasun, et al.
(författare)
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Climate resilient interconnected infrastructure: Co-optimization of energy systems and urban morphology
- 2021
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Ingår i: Applied Energy. - : Elsevier BV. - 1872-9118 .- 0306-2619. ; 285
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Tidskriftsartikel (refereegranskat)abstract
- Co-optimization of urban morphology and distributed energy systems is key to curb energy consumption and optimally exploit renewable energy in cities. Currently available optimization techniques focus on either buildings or energy systems, mostly neglecting the impact of their interactions, which limits the renewable energy integration and robustness of the energy infrastructure; particularly in extreme weather conditions. To move beyond the current state-of-the-art, this study proposes a novel methodology to optimize urban energy systems as interconnected urban infrastructures affected by urban morphology. A set of urban morphologies representing twenty distinct neighborhoods is generated based on fifteen influencing parameters. The energy performance of each urban morphology is assessed and optimized for typical and extreme warm and cold weather datasets in three time periods from 2010 to 2039, 2040 to 2069, and 2070 to 2099 for Athens, Greece. Pareto optimization is conducted to generate an optimal energy system and urban morphology. The results show that a thus optimized urban morphology can reduce the levelized cost for energy infrastructure by up to 30%. The study reveals further that the current building form and urban density of the modelled neighborhoods will lead to an increase in the energy demand by 10% and 27% respectively. Furthermore, extreme climate conditions will increase energy demand by 20%, which will lead to an increment in the levelized cost of energy infrastructure by 40%. Finally, it is shown that co-optimization of both urban morphology and energy system will guarantee climate resilience of urban energy systems with a minimum investment.
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| 45. |
- Thies, Fabian, 1984, et al.
(författare)
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Wind-assisted, electric, and pure wind propulsion - the path towards zero-emission RoRo ships
- 2023
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Ingår i: Ships and Offshore Structures. - : Informa UK Limited. - 1754-212X .- 1744-5302. ; 18:8, s. 1229-1236
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Tidskriftsartikel (refereegranskat)abstract
- Electrical and wind propulsion, together with energy stored in batteries and renewable energies harnessed onboard, can lead the way towards zero-emission ships. This study compares wind propulsion solutions and battery storage possibilities for a RoRo ship operating in the Baltic Sea. The ship energy systems simulation model ShipCLEAN is used to predict the performance of the zero-emission ship in real-life operating conditions. The study showcases how ships can be transferred from a conventional, diesel-powered to a zero-emission ship. For the zero-emission ship, all energy needed for auxiliaries and propulsion is taken from renewable sources onboard or from batteries. Challenges and opportunities, as well as necessary adaptions of the route and logistics, are discussed. Results of the study present which wind propulsion technology is the most suitable for the example RoRo ship, and how the installation of suitably sized battery packs for zero-emission operation affects the cargo capacity of the ship.
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| 46. |
- Thomas, Jean-Baptiste, et al.
(författare)
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A comparative environmental life cycle assessment of hatchery, cultivation, and preservation of the kelp Saccharina latissima
- 2021
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Ingår i: Ices Journal of Marine Science. - : Oxford University Press (OUP). - 1054-3139 .- 1095-9289. ; 78:1, s. 451-467
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Tidskriftsartikel (refereegranskat)abstract
- Seaweed cultivation and processing industries could contribute to sustainable blue growth and the European bioeconomy. This article contributes a case study evaluation of environmental sustainability of preserved brown seaweed Saccharina latissima by means of environmental life cycle assessment of a pilot facility in Sweden. The study accounts for nutrient bioremediation and carbon capture and includes two alternative hatchery processes, a 2-ha longline cultivation, and four alternative preservation methods (hang-drying outdoors, heated air-cabinet drying, ensiling, and freezing). The study found that as a result of carbon capture and nitrogen and phosphorus uptake (bioremediation) by seaweed, more CO2 and PO4 equivalents are (temporarily) absorbed than emitted by the supply chain. The extent of emissions is most affected by preservation methods undertaken. Impact profiles of the supply chain show that the greatest impact shares result from freezing and air-cabinet drying, both the two most energy-intensive processes, followed by the cultivation infrastructure, highlighting strategic optimization opportunities. Hatchery processes, harvesting, and the low-energy ensilage and hang-drying outdoors were found to have relatively small impact shares. These findings presage the environmentally friendliness of seaweed-based products by documenting their potential to mitigate eutrophication and climate change, even when taking a life cycle perspective.
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| 47. |
- Morozovska, Kateryna, et al.
(författare)
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Trade-offs of wind power production: A study on the environmental implications of raw materials mining in the life cycle of wind turbines
- 2024
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Ingår i: Journal of Cleaner Production. - : Elsevier Ltd. - 0959-6526 .- 1879-1786. ; 460
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Tidskriftsartikel (refereegranskat)abstract
- The energy demand in Sweden is increasing due to the growing electrification, and to meet this need, the generation must be expanded. Wind power generation is a very attractive renewable power production alternative for Sweden because of the favorable weather conditions. Research looks at how much wind energy may be deemed sustainable. Increased energy demand puts pressure on the government and industry to build more wind farms and, as a result, produce more wind turbines. Raw materials are necessary for wind turbines to provide a secure transition to green energy technologies. To meet these demands, the materials from various countries should efficiently contribute towards the Sustainable Development Goals (SDGs). This paper gathers information about raw resources from diverse nations worldwide. All materials are mapped to the country where they are produced using social science criteria. A few nations are chosen based on a sample approach for further analysis, and the implications of mining operations are investigated. Finally, the direct and indirect effects of the SDGs are considered. Based on the data gathered, recommendations and considerations are given to avoid or mitigate the repercussions of raw materials mining and make wind power generation more socially and environmentally sustainable.
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| 48. |
- Adler, Anneli, et al.
(författare)
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Lignin-first biorefining of Nordic poplar to produce cellulose fibers could displace cotton production on agricultural lands
- 2022
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Ingår i: Joule. - : Elsevier BV. - 2542-4351. ; 6:8, s. 1845-1858
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Tidskriftsartikel (refereegranskat)abstract
- Here, we show that lignin-first biorefining of poplar can enable the production of dissolving cellulose pulp that can produce regenerated cellulose, which could substitute cotton. These results in turn indicate that agricultural land dedicated to cotton could be reclaimed for food production by extending poplar plantations to produce textile fibers. Based on climate-adapted poplar clones capable of growth on marginal lands in the Nordic region, we estimate an environmentally sustainable annual biomass production of ∼11 tonnes/ha. At scale, lignin-first biorefining of this poplar could annually generate 2.4 tonnes/ha of dissolving pulp for textiles and 1.1 m3 biofuels. Life cycle assessment indicates that, relative to cotton production, this approach could substantially reduce water consumption and identifies certain areas for further improvement. Overall, this work highlights a new value chain to reduce the environmental footprint of textiles, chemicals, and biofuels while enabling land reclamation and water savings from cotton back to food production.
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| 49. |
- Muangmeesri, Suthawan, 1997-, et al.
(författare)
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Recycling of Polyesters by Organocatalyzed Methanolysis Depolymerization : Environmental Sustainability Evaluated by Life Cycle Assessment
- 2024
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Ingår i: ACS Sustainable Chemistry and Engineering. - : American Chemical Society (ACS). - 2168-0485. ; 12:10, s. 4114-4120
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Tidskriftsartikel (refereegranskat)abstract
- Polyethylene terephthalate (PET) is one of the most common plastics and can be cascaded mechanically during its life cycle. However, recycling affects the mechanical properties of the material, and the virgin material is constantly in demand. If a worn material could be depolymerized to its chemical building blocks, then a virgin polymer could be generated from old fibers. In this work, we have developed a benign organo-catalytic depolymerization of PET to yield dimethyl terephthalate (DMT) and ethylene glycol (EG) without the need for purification of generated monomers. By recirculating the solvent and organo-catalyst, a solvent/substrate ratio of 3:1 was achieved. The depolymerization was successfully applied to other polyesters, polycarbonates, and polycotton. The cotton isolated from the polycotton depolymerization was successfully processed into viscose fibers with a tenacity in the range of nonwaste cotton-derived viscose filaments. The global warming potential (GWP) of PET depolymerization was evaluated by using life cycle assessment (LCA). The GWP of 1 kg PET recycling is 2.206 kg CO2 equivalent, but the process produces DMT, EG, and heat, thereby avoiding the emissions equivalent to 4.075 kg CO2 equivalent from the DMT, EG, and steam-energy production through conventional pathways. Thus, the net result potentially avoids the emission of 1.88 kg of CO2 equivalent. The impact of this process is lower than that of waste PET incineration and conventional PET recycling technologies.
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| 50. |
- Schade, Jutta, et al.
(författare)
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Greenhouse gas emissions and sustainability of green roofs and stormwater systems at a district level – comparisons with a life cycle perspective
- 2022
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Ingår i: Proceedings of LCM 2021: 10<sup>th</sup> International Conference on Life Cycle Management. - : EDP Sciences.
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Konferensbidrag (refereegranskat)abstract
- To reach future climate targets, it is important to verify that materials and technologies used for construction are sustainable and have a minimal environmental impact. The goal of this project was to add a broad life cycle perspective for quantifying energy and greenhouse gas emission, from the upstream flow of the construction process and the operational phase by including buildings and stormwater systems at a district level. The hypothesis was that green roofs might have a higher impact on greenhouse gas emissions as more material is needed compared to a standard roof. In return, green roofs reduce and retain stormwater, which may reduce the risk of hydraulic overloading in connected stormwater systems. This may lead to reduced CO2 emission if an upgrade of existing systems is not necessary. To evaluate this complex issue, a framework was developed combining construction modelling, energy simulation, stormwater system modelling, and life cycle assessment. The result of this theoretical study indicates that green roofs reduce and retain stormwater but are in most cases not sufficient to reduce the risk of hydraulic overloading in connected stormwater systems. The results demonstrated that green roofs should be not solely implemented to reduce and retain stormwater in the Nordic climate.
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