This study contributes to exploring methodologies and approaches to sustainability reporting in the district heating sector, emphasizing the importance for open-access and decoding of environmental data to help mitigate climate impacts. The study investigates avenues for enhancing the understanding and accuracy of emission calculations with a consumption-based perspective related to district heating in Sweden. The study examines contemporary open data sources related to district heating in Sweden and assesses the challenges and obstacles associated with sustainability reporting, and semi-structured interviews were conducted to evaluate data quality and field challenges. The study also performed computations on emissions from district heating, aiming for high geographical resolution and consumption-based calculations. Based on previous inputs, the thesis constructed its own models to compute emissions.   The study’s results identified data sources available, it was observed that many of them lack the transparency and documentation needed for third party users. Despite covering the same topics, differences in data were identified, likely due to varying methodologies for activity and emission data production. This underscores the challenge in selecting appropriate frameworks and methodologies for sustainability reporting, and its significant impact. Two main challenges were identified because of this, virtual networks and the allocation of emissions, both highly contested concepts. The computations demonstrated that it is possible to increase the granularity of emissions, using emission factors for district heating energy specifically linked to municipal areas. It also showed that using different data sources and methodologies can lead to varied outcomes, although they generally align with national trends. It is important to consider this variability when interpreting results and making decisions based on such data. Modelling to increase higher geographical resolution indicated that downscaling to postcode level is achievable but laborious and time-consuming. However, this approach can enhance understanding of local variations, aiding in the comprehension of emission patterns. Moreover, ensuring data transparency and accessibility can aid local initiatives and inform strategies for reduction, which are crucial for climate change mitigation efforts.

This dissertation focuses on the introduction and development of an integrated model-based design and optimization platform to solve the optimal design and optimal control, or hardware and software co-design, problem for hybrid electric propulsion systems. Specifically, the hybrid and plug-in hybrid electric powertrain systems with diesel and natural gas (NG) fueled compression ignition (CI) engines and large Li-ion battery energy storage system (ESS) for propelling a hybrid electric marine vessel are investigated. The combined design and control optimization of the hybrid propulsion system is formulated as a bi-level, nested optimization problem. The lower-level optimization applies dynamic programming (DP) to ensure optimal energy management for each feasible powertrain system design, and the upper-level global optimization aims at identifying the optimal sizes of key powertrain components for the powertrain system with optimized control. Recently, Li-ion batteries became a promising ESS technology for electrified transportation applications. However, these costly Li-ion battery ESSs contribute to a large portion of the powertrain electrification and hybridization costs and suffer a much shorter lifetime compared to other key powertrain components. Different battery performance modelling methods are reviewed to identify the appropriate degradation prediction approach. Using this approach and a large set of experimental data, the performance degradation and life prediction model of LiFePO4 type battery has been developed and validated. This model serves as the foundation for determining the optimal size of battery ESS and for optimal energy management in powertrain system control to achieve balanced reduction of fuel consumption and the extension of battery lifetime. In modelling and design of different hybrid electric marine propulsion systems, the life cycle cost (LCC) model of the cleaner, hybrid propulsion systems is introduced, considering the investment, replacement and operational costs of their major contributors. The costs of liquefied NG (LNG), diesel and electricity in the LCC model are collected from various sources, with a focus on present industrial price in British Columbia, Canada. The greenhouse gas (GHG) and criteria air pollutant (CAP) emissions from traditional diesel and cleaner NG-fueled engines with conventional and optimized hybrid electric powertrains are also evaluated. To solve the computational expensive nested optimization problem, a surrogate model-based (or metamodel-based) global optimization method is used. This advanced global optimization search algorithm uses the optimized Latin hypercube sampling (OLHS) to form the Kriging model and uses expected improvement (EI) online sampling criterion to refine the model to guide the search of global optimum through a much-reduced number of sample data points from the computationally intensive objective function. Solutions from the combined hybrid propulsion system design and control optimization are presented and discussed. This research has further improved the methodology of model-based design and optimization of hybrid electric marine propulsion systems to solve complicated co-design problems through more efficient approaches, and demonstrated the feasibility and benefits of the new methods through their applications to tugboat propulsion system design and control developments. The resulting hybrid propulsion system with NG engine and Li-ion battery ESS presents a more economical and environmentally friendly propulsion system design of the tugboat. This research has further improved the methodology of model-based design and optimization of hybrid electric marine propulsion systems to solve complicated co-design problems through more efficient approaches, and demonstrated the feasibility and benefits of the new methods through their applications to tugboat propulsion system design and control developments. Other main contributions include incorporating the battery performance degradation model to the powertrain size optimization and optimal energy management; performing a systematic design and optimization considering LCC of diesel and NG engines in the hybrid electric powertrains; and developing an effective method for the computational intensive powertrain co-design problem. / Graduate

Införandet av byggnadsstadgan 1874 medförde ett förbud mot byggande av flerbostadshus i trä om högre än två våningar på grund av omfattande bränder. Detta hämmande utvecklingen av trä då de större företagen byggde flervåningshus högre än två våningar vilket ledde till byggande av annat material än trä. I dagsläget är byggnadsmaterialet betong det dominerande materialet inom byggbranschen, speciellt inom byggandet av flerbostadshus. De senaste 15 åren har andelen byggda flerbostadshus med en stomme av betong varierat mellan 80 och 91 procent. Byggnad- och fastighetsbranschen står idag för cirka 21 % av Sveriges totala utsläpp av växthusgaser, en totalsiffra på cirka 21 miljoner ton koldioxidekvivalenter. Under de senaste åren har både företag och privatpersoner i både Sverige och länder runt om i världen fått upp ögonen för de miljöproblem som världen står inför och har blivit mer miljömedvetna och letar oavbrutet efter lösningar på hur samhället kan minska koldioxidutsläppen. Resultaten i detta examensarbete för de tillhandahållna projekten som detta arbete utgått från är att byggnaden konstruerad i korslimmat trä är det material som är att föredra ur ett miljö- och kostnadsperspektiv. Dock har detta arbete enbart avhandlat bärande inner- och ytterväggar samt bjälklag. / With the introduction of the 1874 building code, a prohibation against multi-storey apartment buildings built in wood was implemented, mainly because of the widespread fires throughout the years. Since most of the bigger companies built their apartment complexes in levels higher than two, it meant they had to build in construction material other than wood - thus hampering woods’ development in the field of construction. As of today, concrete is still the dominating material within construction industry, especielly when it comes to building apartment complexes. Theamount of partment buildings built with its framework consisting mostly of concrete has varied between 80 to 91 percent the past 15 years. The building industry and real estate industry represent approximately 21 % of Swedens greenhouse gas emissions, a total figure of about 21-million-ton carbon dioxide equivalents. In recent years, people and companies in Sweden and countries around the globe have become more aware of the environmental issues and its consequences that we’ll soon face and are therefore working on finding solutions on how society can reduce carbon dioxide emissions. The results presented in this thesis, which represents the projects that were provided, shows that the building built with its framing in CLT is the more sustainable material from an environmental perspective and more profitable economically. It should however be mentioned that calculations were only done for the load-bearing inner and outer walls and the floor joist.