| 1. |
- Haraldsson, Joakim, 1990-
(author)
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Improved Energy Efficiency in the Aluminium Industry and its Supply Chains
- 2020
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Doctoral thesis (other academic/artistic)abstract
- Energy is an essential resource in the daily lives of humans. However, the extraction and use of energy has an impact on the environment. The industrial sector accounts for a large share of the global final energy use and greenhouse gas (GHG) emissions. The largest source of industrial GHG emissions is energy use. The production and processing of aluminium is energy- and GHG-intensive, and uses significant amounts of fossil fuels and electricity. At the same time, the global demand for aluminium is predicted to rise significantly by the year 2050. Improved energy efficiency is one of the most important approaches for reducing industrial GHG emissions. Additionally, improved energy efficiency in industry is a competitive advantage for companies due to the cost reductions that energy efficiency improvements yield.The aim of this thesis was to study improved energy efficiency in the individual companies and the entire supply chains of the aluminium industry. This included studying energy efficiency measures, potentials for energy efficiency improvements and energy savings, and which factors inhibit or drive the work to improve energy efficiency. The aim and the research questions were answered by conducting a literature review, focus groups, questionnaires and calculations of effects on primary energy use, GHG emissions, and energy and CO2 costs.This thesis identified several energy efficiency measures that can be implemented by the individual companies in the aluminium industry and the aluminium casting foundries. The individual companies have large potentials for improving their energy efficiency. Energy efficiency measures within the electrolysis process have significant effects on primary energy use, GHG emissions, and energy and CO2 costs. This thesis showed that joint work between the companies in the supply chains of the aluminium industry is needed in order to achieve further energy efficiency improvements compared to the companies only working on their own. The joint work between the companies in the supply chain is needed to avoid sub-optimisation of the total energy use throughout the entire supply chain. Better communication and closer collaboration between all the companies in the supply chain are two of the most important aspects of the joint work to improve energy efficiency. An energy audit for the entire supply chain could be conducted as a first step in the joint work between the companies in the supply chains. Another important aspect is to increase the use of secondary aluminium or remelted material waste rather than primary aluminium.The companies in the Swedish aluminium industry and the aluminium casting foundries have come some way in their work to improve energy efficiency within their own facilities. However, the results in this thesis indicate that cost-effective technology and improved management can, in total, save 126–185 GWh/year in the Swedish aluminium industry and 8–15 GWh/year in the Swedish aluminium casting foundries.This thesis identified several demands regarding economics, product quality and performance, and environment placed on the companies and products in the supply chains that affect energy use and work to improve energy efficiency. These demands can sometimes counteract each other, and some demands are more important to meet than improving energy efficiency. This implies that improving the energy efficiency of the supply chains as well as designing products so they are energy-efficient in their use phase can sometimes be difficult. The results in this thesis indicate that it would be beneficial if the companies reviewed these demands to see whether any of them could be changed.Both the economic aspects and demands from customers and authorities were shown to be important drivers for improved energy efficiency in the supply chains. However, placing demands on energy-efficient production and a company’s improved energy efficiency would require those placing the demands to have deeper knowledge compared to demanding green energy, for example. Requiring a company to implement an energy management system to ensure active work to improve energy efficiency would be easier for the customer than demanding a certain level of energy efficiency in the company’s processes. Additionally, energy audits and demands on conducted energy audits could act as drivers for improved energy efficiency throughout the supply chains.This thesis showed that the most important barriers to improved energy efficiency within the individual companies include different types of risks as well as the cost of production disruption, complex production processes and technology being inappropriate at the site. Similar to the supply chains, important drivers for improved energy efficiency within the individual companies were shown to be economic aspects and demands from customers and authorities. However, the factors that are most important for driving the work to improve energy efficiency within the individual companies include the access to and utilisation of knowledge within the company, corporate culture, a longterm energy strategy, networking within the sector, information from technology suppliers and energy audits.
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| 2. |
- Kastbom, Lisa, 1978-
(author)
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A good death from the perspective of patients with severe illness and advance care planning (ACP) in patients near end-of-life
- 2021
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Doctoral thesis (other academic/artistic)abstract
- Previous research has indicated that what constitutes a good death is heterogenic and complex although there are some recurrent themes and similarities regardless individual background factors. Studies on advance care planning (ACP), i.e. making proactive plans regarding content of care and treatment limitations, on nursing home (NH) patients are rare. Positive effects of ACPs are shown, but also that these often are lacking. The overall aim with this thesis was to explore the perceptions of a good death from the perspective of patients with severe illness and to investigate, from different perspectives, experiences of ACP in a NH context. In paper I, patients with cancer in a palliative phase were interviewed on their perceptions of a good death. Death was viewed as a process and previous experiences on the death of others influenced their own perceptions. A good death was associated with living with the prospect of imminent death, preparing oneself and others for one’s death and dying comfortably, e.g. without suffering, with independence and with social relations intact. Some were comforted by their belief that death is predetermined, and that after death, there is something else. Others felt uncomfortable when they viewed death as the end of the existence. In paper II, nurses and physicians were interviewed on their experiences of the factors that shape the ACP process in NHs. Exploration of the patient’s preferences regarding content of care and treatment limitations was important, as well as integration of the patient’s preferences and the views of the family members and staff concerning these questions. ACP documentation had to be clear, updated and available for staff and the implementation and reevaluation of ACP were also considered important, according to the participants. Significance of clinicians’ perceiving beneficence as well as fear of accusations of maleficence were shown to be essential factors to contemplate. In a retrospective chart review (paper III), medical records of 367 deceased NH patients were analysed. A high prevalence of ACP was shown, using two different definitions of ACP (ACP I and ACP II). Moreover, adherence to the ACP content was strong and positive associations were seen between ACP and variables of the three research aims, such as: diagnosis (dementia), physician attendance at NH and end-of-life (EOL) care. In paper IV, family members of deceased NH patients were interviewed on their experiences of ACP in NHs. EOL issues were challenging to talk about, although the family members appreciated staff raising these questions. The patient’s preferences were sometimes explicitly or implicitly communicated. However, in some cases, family members had a feeling of the patient’s preferences, although they had not been clearly communicated. Everyday details symbolised staff commitment. The family members viewed the nurse as central. The physician was described as absent and ACP meetings often went unnoticed. Both involvement and lack of involvement could cause the family members feelings of guilt. In conclusion, we found that what constitutes a good death is highly individual, although recurrent themes are seen. EOL conversations are important and challenging and need staff training and experience. It seems important to support healthcare staff not only to initiate ACP in NH patients, but also to involve the patient and family members in the ACP and planning EOL care. Making proactive plans regarding content of care including treatment limitations, could enable patient autonomy, optimise the chances for the patient to experience a good death and enhance for the family members during the dying trajectory and after the patient’s death.
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| 3. |
- Andersson, Elias, 1989-
(author)
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Enabling industrial energy benchmarking : Process-level energy end-use, key performance indicators, and efficiency potential
- 2020
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Doctoral thesis (other academic/artistic)abstract
- One of the greatest challenges of our time is global climate change. A key strategy for mitigating the emission of greenhouse gases is the improvement of energy efficiency. Manufacturing industry stands for a large share of global energy end-use but has yet to achieve its full energy efficiency potential. A barrier to untapping this potential is the lack of detailed data on industrial energy end-use at the process level, preventing the development of sound, bottom-up energy key performance indicators (KPIs). This hampers the ability to create a profound strategy for improving industrial energy efficiency because it is not known in which end-use processes the largest energy efficiency potential is to be found. Increasing knowledge about energy end-use at the process level also increases the possibility for energy comparisons, i.e. benchmarking, at the process level.This thesis aimed to investigate how to further enable industrial energy benchmarking at the process level, primarily for the pulp and paper and wood industries. Relevant benchmarking requires that data on energy end-use is collected using a common, harmonized categorization of processes and that joint energy KPIs are applied. Therefore, suggestions for standardized categorizations of end-use processes were investigated for the studied industries.Based on the calculations, and under the assumptions made in this thesis for estimating the energy efficiency potential of end-use processes, diversity was found between industries around which type of processes have the largest efficiency potential. It also emerged that, due to the lack of detailed data about energy end-use and lack of information about energy efficiency measures, processes accounting for a significant share of the energy efficiency potential in the wood industry risk being overlooked. It is not certain that current energy policies are sufficient to reach the full potential identified. The lack of information about energy end-use and energy efficiency measures implies that neither industrial actors nor policy-makers are able to develop thorough energy strategies or roadmaps for improved energy efficiency.While the outcomes of this thesis show that a large share of Swedish pulp and paper mills carry out energy benchmarking to some degree, energy managers emphasized that benchmarking in this particular industry is difficult because it requires a deep understanding of the industry’s heterogenous and integrated processes. This thesis proposes a widened perspective on energy benchmarking and its role in industrial energy management; namely, also considering the process of how energy KPIs are implemented within in-house energy management. A process that enhances energy management includes the continuous monitoring, visualization, and revision of KPIs. In this thesis, a method is developed that encourages the bottom-up implementation of energy KPIs in the pulp and paper industry, which further enables industrial energy benchmarking.
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| 4. |
- Angelov, Angel G., 1983-
(author)
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Methods for interval-censored data and testing for stochastic dominance
- 2018
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Doctoral thesis (other academic/artistic)abstract
- This thesis includes four papers: the first three of them are concerned with methods for interval-censored data, while the forth paper is devoted to testing for stochastic dominance.In many studies, the variable of interest is observed to lie within an interval instead of being observed exactly, i.e., each observation is an interval and not a single value. This type of data is known as interval-censored. It may arise in questionnaire-based studies when the respondent gives an answer in the form of an interval without having pre-specified ranges. Such data are called self-selected interval data. In this context, the assumption of noninformative censoring is not fulfilled, and therefore the existing methods for interval-censored data are not necessarily applicable.A problem of interest is to estimate the underlying distribution function. There are two main approaches to this problem: (i) parametric estimation, which assumes a particular functional form of the distribution, and (ii) nonparametric estimation, which does not rely on any distributional assumptions. In Paper A, a nonparametric maximum likelihood estimator for self-selected interval data is proposed and its consistency is shown. Paper B suggests a parametric maximum likelihood estimator. The consistency and asymptotic normality of the estimator are proven.Another interesting problem is to infer whether two samples arise from identical distributions. In Paper C, nonparametric two-sample tests suitable for self-selected interval data are suggested and their properties are investigated through simulations.Paper D concerns testing for stochastic dominance with uncensored data. The paper explores a testing problem which involves four hypotheses, that is, based on observations of two random variables X and Y, one wants to discriminate between four possibilities: identical survival functions, stochastic dominance of X over Y, stochastic dominance of Y over X, or crossing survival functions. Permutation-based tests suitable for two independent samples and for paired samples are proposed. The tests are applied to data from an experiment concerning the individual's willingness to pay for a given environmental improvement.
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| 5. |
- Lindkvist, Emma, 1984-
(author)
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System studies of biogas production : comparisons and performance
- 2020
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Doctoral thesis (other academic/artistic)abstract
- Biogas has the potential to be part of the transition towards a more sustainable energy system. Biogas is a renewable energy source and can play an important role in modern waste management systems. Biogas production can also help recirculate nutrients back to farmland. Besides all this, biogas is a locally produced energy source with the potential to increase global resource efficiency, since it can lead to more value and less waste, as well as decreased negative environmental effects. However, biogas production systems are complex, including different substrates, different applications for biogas and digestate, and different technology solutions for digestion, pre-treatment and for upgrading the raw gas. To increase the development of biogas production systems, knowledge sharing is a key factor. To increase this knowledge sharing, comprehensible analysis and comparisons of biogas production systems are necessary. Thus, studies are needed to verify the resource efficiency of biogas production systems from different perspectives.The aim of this thesis is to perform a systems analysis of biogas production systems and to explore how to analyse and compare biogas production systems. An additional aim is to study biogas production systems from a systems perspective, with a focus on environment, energy and economy. Studying biogas production systems from different system levels, as well as from different approaches, is beneficial because it results in deeper knowledge of biogas systems and greater opportunities to identify synergies.Systems studies of biogas are important, since biogas systems are often complex and integrated with other systems. In this thesis, biogas systems analyses are performed at different levels. In the widest system study, classifications of different biogas plants are analysed and classifications in different European countries are compared, with the prospect of paving the way for a new common classification for biogas plants in Europe. Today, classifications vary between countries, and hence comparisons of plants in different countries are difficult. In the narrowest system study, a new methodology for analysing energy demand at different biogas production plants has been developed. The aim was to develop a methodology that is applicable for all kinds of biogas plants with energy inputs. The methodology describes the process of analysing energy demand and allocating energy to sub-processes and unit processes.Further, an approach for assessing the resource efficiency of different treatment options for organic waste was designed. The approach includes environmental, economic and energy perspectives, and was applied to five different regions with several food manufacturing companies. A study of treatment options for organic waste from a single food company was also conducted. The results showed that biogas production is a resource-efficient way to treat waste from the food industry. The approach enables a wider analysis of biogas systems, and the results from the applications show the complexity of assessing resource efficiency. It is also shown that it is important to understand that the resource efficiency of a system is always in relation to the substituted system.In this thesis, three different approaches to analysing biogas production systems are presented: categorization, resource efficiency analysis and energy demand analysis. These approaches all contribute to the understanding of biogas systems and can help, in different ways, to increase knowledge about biogas systems in the world. If knowledge about different biogas systems can be easily disseminated, more of the unused potential of biogas production may be realized, and hence more fossil fuels can be replaced within the energy system.
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