| 1. |
- Bergman, Filip, 1992-
(author)
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Sustainability performance of multi-utility tunnels : Sustainability assessments for furthering knowledge and understanding
- 2022
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Licentiate thesis (other academic/artistic)abstract
- The multi-utility tunnel has received increased attention as an alternative method for the installation of subsurface infrastructure for the distribution of electricity, water, sewage and district heating. In previous research, the multi-utility tunnel (MUT) has been described as a more sustainable technology compared to the conventionally used technique where the cables and pipes are placed with open-cut excavation (OCE), especially when the entire life cycle is taken into account. This thesis aims to contribute to an improved understanding of MUT's sustainability performance in relation to conventional installation using open-cut excavation. This is done by using literature study, interview study and quantitative sustainability assessments to gain an understanding of the current state of knowledge. Furthermore, this thesis also focuses on how knowledge can be deepened with the help of quantitative sustainability assessments and the challenges of conducting this type of assessment. This thesis shows that the state of knowledge regarding MUT's sustainability performance is low and scattered, with a lack of a holistic approach. Direct economic performance has gained the most attention, followed by indirect and social impact, and the environmental impact has so far barely been assessed. The sustainability performance depends to a large extent on the conditions of the specific case, and these should be considered when assessing the technology. Quantitative assessments have the potential to help deepen the knowledge of the sustainability implications of using MUT. The characteristics of MUT have some similarities with other types of physical infrastructure. Similarities are that the systems are long-lived, have project conditions that affect sustainability performance, and impact a broad spectrum of actors. One difference to typical infrastructure systems is that the owner and management structure of MUT is, by design, more complex as several types of utility systems are in use. The characteristics of MUT give some practical considerations that need to be addressed: data availability, including practitioners; detailed data; transparency; and flexibility. This thesis highlights the complexity of assessing MUT´s sustainability performance and advocates that future studies should have a learning-oriented approach so that the knowledge level can collectively and gradually improve over time rather than focusing on decision-oriented studies.
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| 2. |
- Dahlgren, Sofia, 1992-
(author)
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The role of biogas in a more sustainable energy system in Sweden
- 2019
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Licentiate thesis (other academic/artistic)abstract
- There are numerous problems in the world that need to be dealt with in order to achieve sustainable development. The energy system has significant negative impacts on many of these problems, and there is a need for a transition towards more sustainable energy. Sweden has already started this transition and is using large amounts of renewable energy. However, within the transport sector and the manufacturing sector in particular, large amounts of fossil fuels are still used. Biogas is one alternative that can help solve several sustainability problems and that could be part of a future more sustainable energy system. However, it is not certain what biogas is most suitable to be used for.The aim of this thesis is to investigate how biogas should be used in a future more sustainable energy system, by answering three research questions: 1) In what ways can biogas be used in a more sustainable energy system? 2) How can we assess whether biogas is suitable in a specific context? and 3) What determines whether it is easy or difficult for a user to start using biogas? These questions are explored in a Swedish context using four appended articles, which are based on two collaborative projects using a combination of workshops, literature reviews and interviews.Biogas can be used for heat, electricity or fuel in the manufacturing or transport sector. In Sweden, heat and electricity are mainly of interest for smaller production scales, while production on larger scales will likely be dominated by upgrading mostly to CBG but also to LBG. CBG can be used for less energy-intensive purposes, such as cars or buses, while the growing interest in LBG in Sweden may open up new market segments for biogas which are more energy-intensive, such as heavy trucks or shipping, or in geographical locations that are further away from the site of production.Several sustainability assessment methods exist that can be used to evaluate whether biogas is suitable in a specific context, such as multi-criteria assessments or scenario analyses. These methods can include a number of different aspects that are relevant to biogas use, such as GHG emissions, safety issues, and the vitality of the surrounding region. In order to introduce biogas, six main factors were identified that can make this easier or more difficult: technical maturity, tank volume, distance between the producer and the user, scale of energy use, policies and costs, and strategies of individual organizations.Overall, the rise in LBG production creates new opportunities for biogas use in both geographical and usage areas that did not previously use biogas. There is no simple answer to what biogas should be used for in the future – rather, this depends on the circumstances. It is also possible that the usage areas that are most suitable now for biogas might not be the most suitable areas in the future, depending on developments within, for example, the electricity system and hydrogen. However, CBG and LBG are likely to dominate biogas production in Sweden until then.
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| 3. |
- Fältström, Emma, 1987-
(author)
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Towards the Control of Microplastic Pollution in Urban Waters
- 2020
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Licentiate thesis (other academic/artistic)abstract
- Water pollution has long been considered a challenge in urban areas, and new types of pollution are continuously introduced to society. Urban wastewater and stormwater act as transport pathways of pollution from urban areas to receiving waterways. Microplastics are a new type of pollution that is being highlighted as problematic, and the presence of microplastics is widespread in the environment. The knowledge about behaviour, sources and transport pathways is still limited. Still, there have been suggestions for ways to control microplastic pollution. Moreover, many other pollutants have been introduced, and to a various extent controlled, in the urban water system before, which means that there are strategies for pollution control in place.The problem of microplastic pollution is receiving attention from both research and policy. Therefore, there is a need to simultaneously explore ways to handle the pollution and learn more about the flows of microplastics. The aim of this thesis is to contribute to the understanding of flows of microplastics in urban waters and investigate strategies and measures that can control the flows. This aim has been addressed through three different studies presented in the three appended papers. The empirical material was gathered between 2017 and 2020 using both quantitative and qualitative methods. The flows of microplastics were investigated using a quantitative approach with inspiration from substance flow analysis. Strategies and measures to control pollution were investigated by means of analyses of documents, literature review and interviews.In terms of flows, the results show that laundry seems to be a large contributor to the wastewater system, while the contribution from cigarette filters was smaller than anticipated. Littering, in general, as well as paint, are potentially important sources of microplastics where the understanding is very limited. In terms of strategies and measures to control the flows, there are both preventive and treatment options for microplastics. As microplastics are a diverse pollutant group, several different solutions are needed. Some aspects that influence control efforts are related to the properties and behaviour of the specific pollutant and can therefore be more or less suitable for different pollutants. Other aspects are more general, such as what compartments are seen as valuable and prioritised in terms of protection. Further, treatment moves the pollution from the water to another medium, and this movement also needs to be considered.Challenges in terms of changing, limited or even lack of legislation, as well as unclear responsibility, and problems with collaboration among urban actors also impact the possibilities to control pollution. The case of microplastics also raises questions about when and how pollution should be controlled and by whom. Further, emerging practices in the urban water system, such as source separation, pipe-separation, and water reuse, will have implications for how pollution will be handled in the future.
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| 4. |
- Hegazy, Eman, 1978-
(author)
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Sustainable Management of Wire-based Infrastructure : On the Multifaceted Challenges of Infrastructure Management in the Swedish Context
- 2024
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Licentiate thesis (other academic/artistic)abstract
- Cities, as key players in global sustainable development, are linked to challenges and opportunities driven by urbanization's resource consumption and environmental impacts. This context highlights the critical role of urban infrastructure in fostering sustainability, particularly the role of wire-based infrastructure systems (WBIS). The management, maintenance, and renewal of WBIS are vital to ensuring their long-term efficiency, yet they present challenges across technical, environmental, and societal dimensions. The positioning of these systems beneath urban streets introduces complexities, from accelerated wear to costly excavations, with a wide range of environmental consequences. Beyond the physical implications, the financial, policy, and management practices governing WBIS also contribute to their sustainable development challenges. This study, centered on Linköping's water network in Sweden as a case study, aims to unravel these multifaceted dynamics and answer key research questions regarding the management, challenges, influencing factors, and strategies for improving the maintenance and renewal of urban WBIS. Based on a mixed method approach, the case study utilized both qualitative and quantitative methods, including interviews, workshops, and data analysis. The results highlighted Linköping's UWI challenges, encompassing aging infrastructure, limited renewal rates, and financial constraints. To navigate these challenges, the discussion advocated for a shift towards proactive renewal strategies. The conclusions emphasized the need for an increased funding, strategic planning, proactive coordination among diverse stakeholders, and a balanced approach in budgetary allocations, particularly in considering maintenance and renewal alongside other activities, as crucial for ensuring the longevity and sustainability of the WBIS.
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