Retrofitting measures in old buildings aimed at reducing energy consumption has become a widespread subject and an urgent matter to counteract the effects of climate change and GHGs emissions. The globe has reaffirmed its agreement taken in COP21 to reduce emissions in COP26. The building sector is one of the culprits with a 70 % future energy consumption forecasted by 2050 i.e., the year certain countries aim to carbon neutral (e.g., Sweden). An old building with a severe problem of energy leakage has been studied under the influence of multiple parameters such as building orientation, shading systems, location, Low-E film and an alternative energy supply (GHP). The original building’s EnU amounted to 194.5 kWh/m2•yr; the parameters were applied and orientation of 90⁰ worked best, if the building was being designed, contrary to this case. However, energy reductions, compared to the base model, were actually achieved with the application of Low-E (5%) films and when substituting the heating demand with a GHP (57.5%), LEF-GHP reached (59.2%) and a corresponding decrease in CO2 emissions. Thermal comfort was best achieved with models that had the highest energy consumption such as LEF and ES making it counterproductive in fulfilling the aim of reducing GHG footprint of Rådhuset. The economic feasibility study showed that the installation of a GHP with at least the COP of 4.0 would lead to a shorter payback period than solely applying LEF. A tailored solution of a change in the energy source such as electrified heat supply from renewables combined with LEFs would reduce the energy and emission impact of any building; this would help the building sector reach the envisioned goal of carbon neutrality in 2050.

Denna studie tar upp om det är mer hållbart att renovera en befintlig byggnad eller riva den nuvarande och bygga en ny ur ett klimat perspektiv. Målet är, med hjälp av livscykelanalys, undersöka ämnet. Studien har avgränsats till att fokusera på ekologisk hållbarhet och redovisar endast klimatpåverkan och energibehov. Metoden som har använts är en litteraturstudie där tidigare projekt som stått inför frågan om ätt riva eller renovera?”har beaktats. Dessutom undersöks forskningsartiklar som studerar området. Studien baseras på två svenska skrifter och tre internationella som sedan diskuteras och analyseras. Samtliga artiklar styrker argumentet att renovering är det optimala valet även då nybyggnation kan bidra till energieffektivitet vid driftstadiet. Renovering uppnår i stort sett samma resultat när det gäller energiförbrukning samtidigt som detta alternativ har en lägre klimatpåverkan. / This study will address the sustainability of renovating an existing building compared to demolishing the current one and building a new one. The scope of the study has been limited to ecological sustainability, specifically two parameters; climate impact and energy consumption. The methodology used for this project is a literature study in which previous project essays and research articles investigating the issue of to demolish or renovate?­ is taken into consideration. Where the subject was investigated using a life cycle assessment. This study is based on two Swedish publications and three international ones, which are discussed and analyzed. All included articles support the argument that renovation is the preferred choice, although new construction can contribute to energy efficiency at the operational stage. Compared to demolishing and rebuilding, renovation results in similar energy consumption, while achieving a more modest climate impact.

Cuba’s government has set a goal to generate 24 percent of the country’s electricity from renewable sources by 2030. The country’s many sugar mills have been identified as key contributors to reach this goal as their cogeneration units have the potential to significantly increase Cuba’s electricity production from biomass by upgrading them to bioelectric plants. This study evaluates the feasibility of upgrading the cogeneration unit of George Washington sugar mill in the province of Villa Clara, Cuba. An energy balance of the proposed upgraded scheme is done to deduce its feasibility from an energy perspective. To deduce the project’s feasibility from a financial standpoint its net present value (NPV), internal rate of return (IRR), discounted payback period (DPP) and levelized cost of energy (LCOE) are calculated. The spared CO2 emissions by integrating more biopower in the Cuban electricity system are calculated from the avoided burning of diesel for electricity production. The impact on Cuba’s energy independence is quantified by calculating the avoided diesel imports. The NPV of the proposed scheme is 64.9 MUSD, the IRR is 25.6 percent which is significantly higher than the set discount rate of 6.5 percent, the DPP is 5.3 years and the LCOE is 0.0533 USD/kWh which is lower than the maximum LCOE set by AZCUBA to 0.14 USD/kWh. The avoided CO2 emissions and imported diesel are estimated to be 110,173 tonnes CO2 and 36,724 tonnes diesel each year, respectively. These indicators suggest that the upgrade of George Washington’s cogeneration unit is feasible.​ / Kubas regering har satt som mål att generera 24 procent av landets elektricitet från förnyelsebara källor till år 2030. Landets många sockerbruk har identifierats som nyckelaktörer för att nå detta mål då sockerbrukens kraftvärmeenhet har potential att öka Kubas elproduktion från biomassa genom att uppgradera dem till bioelektriska kraftverk. Denna studie utvärderar möjligheten att uppgradera kraftvärmeenheten på sockerbruket George Washington i provinsen Villa Clara, Kuba. Först görs en energibalans på det föreslagna uppgraderade systemet för att utläsa dess genomförbarhet ur ett energiperspektiv. För att utvärdera projektets genomförbarhet ur ett finansiellt perspektiv beräknas investeringens nettonuvärde (NPV), interna avkastningsgrad (IRR), diskonterade återbetalningstid (DPP) och energiproduktionskostnad (LCOE). De undvikta CO2 utsläppen genom integrering av mer biokraft i det kubanska elsystemet beräknas från den uteblivna förbränningen av diesel för elproduktion i landet. Effekterna på Kubas energioberoende kvantifieras genom att man beräknar den minskade dieselimporten. NPV i det föreslagna uppgraderade systemet är 64,9 MUSD, IRR är 25,6 procent vilket är betydligt högre än den fastställda diskonteringsräntan på 6,5 procent, DPP är 5,3 år och LCOE är 0,0533 USD/kWh vilket är lägre än det maximala LCOE som fastställts av AZCUBA till 0,14 USD/kWh. De uteblivna CO2-utsläppen och minskningen av importerad diesel beräknas uppgå till 110 173 ton CO2 respektive 36 724 ton diesel varje år. Dessa indikatorer tyder på att uppgraderingen av George Washingtons kraftvärmeenhet är genomförbar.​

Ice rinks are energy intense industrial applications. A typical single sheet ice rink in Sweden uses about 1000 MWh/season. A state-of-the art ice rink systems can use less than 500 MWh/season, indicating the potential for improvements. According to several investigations CO2 refrigeration system with heat recovery has proven to be energy-efficient and cost-effective solution in ice rinks.To further improve the efficiency, geothermal function may be added feature. The objective of this study is to evaluate the geothermal function from techno-economic perspective for a typical ice rink in Sweden. Modelling of several scenarios has been performed. Obtained results suggest that CO2 refrigeration system with 2-stage heat recovery, if upgraded with geothermal function, can save between 1.7 to 6.8% of energy annually. In the best case, this study suggests the geothermal function would pay back in 16.4 years. / Ishallar är energikrävande industriella applikationer. En typisk ishall i Sverige använder cirka 1000 MWh / säsong. Ett toppmodernt ishallsystem kan använda mindre än 500 MWh / säsong, vilket indikerar stora förbättringsmöjligheter. Enligt flera undersökningar har CO2-kylsystem med värmeåtervinning visat sig vara energieffektivt och kostnadseffektivt i ishallar.För att ytterligare förbättra effektiviteten kan geotermisk funktion läggas till. Syftet med denna studie är att utvärdera den geotermiska funktionen ur ett tekno-ekonomiskt perspektiv för en typisk ishall i Sverige. En modellering av flera scenarier har utförts. Resultaten antyder att CO2-kylsystem med 2-steg värmeåtervinning, om det uppgraderas med geotermisk funktion, kan spara mellan 1,7 och 6,8% energi årligen. I bästa fall antyder denna studie att den geotermiska funktionen skulle betala tillbaka om 16,4 år.

Due to the increasing climate change concerns, biofuels have attracted more attention in the energy field as potential alternative energy sources. Particularly, microalgal biofuel has stood out because of its higher fuel yield potential and lower water and land demand than terrestrial biomass. Because of its outstanding photosynthetic efficiency, the microalgal technology is also investigated by researchers around the world as a potential biological solution for carbon capturing in the industrial sector. To explore the prospects of microalgal technology in a local context, this research lays it focus on investigating the potentiality of microalgal biofuel in the cement industry on Gotland, which is the largest emitter of greenhouse gases on the island. For this purpose, the thesis implements a series of estimations based on the emission data of Cementa AB, Slite, a picture of the potential production of algal biomass and biofuel was created, followed by comparisons to the energy situation on Gotland. While practical data of the selected microalgae species are presented, the results indicate a high potential of microalgae in the production of algal biofuel and the possibility for algal biofuel to power the industrial sector of Gotland, or even the island entirely. Although the estimations are made based on an assumption where all controlling parameters are assumed to be perfectly manipulated, the results still indicate the significance of microalgal technologies in the near-future bioeconomy and global energy system.

There is a considerable gap between what scientists argue is necessary to avoid the most dramatic consequences of climate change and what governments around the world are currently achieving with their mitigation strategies and national pledges. This is partly due to the general inability to communicate solutions to climate change in a desirable way. Strategic narratives have been found to be a great tool to improve the effectiveness of climate change communication. Common narratives in climate change communication are the “Gore” narrative, “End of the World” narrative, “Climate Target” narrative and the “Green Living” narrative. Sweden has been considered a leading country in the field of sustainability in recent years. However, the newly formed government does not seem to be overly concerned with improving environmental sustainability, considering that their proposed policies would lead to an increase in greenhouse gas emissions for Sweden for the first time in decades. The Swedish Climate Policy Council has been formed in order to evaluate whether Swedish policies are aligned with Sweden’s national climate targets on an annual basis. This thesis examines recent reports of the Swedish Climate Policy Council through a document analysis in order to estimate the effectiveness of their climate change communication. The reports were coded using framework analysis and corresponding narrative statements were identified and categorized in the above mentioned narrative categories. Relative frequency of different types of narratives is analyzed and, based on recent climate change communication research, recommendations for improvements are given. It has been found that the Swedish Climate Policy Council should create a strategic narrative for climate change communication, based on the values of the current government.

Accelerated carbonation is a new CO2 storage method under development as a solution for climate change caused by anthropogenic activities. In accelerated carbonation an alkaline source such as minerals or industrial residues react with carbon dioxide in a presence of slightly acidic solution to produce stable solid carbonates. There are varieties of accelerated carbonation routes which differ in process condition.</p><p>The aim of this study was to evaluate and compare the potential of a slurry route process and a wet route process for the carbonation of basic oxygen furnace (BOF) slag using the CO2 emitted by a conventional natural gas power plant.</p><p>For this purpose a life cycle assessment (LCA) study was performed based on principles and guidelines provided by ISO 14040:2006 and routines and data provided by the SimaPro v8 software package. The material and energy requirements for each of the steps involved in the carbonation process, i.e. pre-treatment of raw material, CO2 compression, transportation, carbonation step, after-treatment and landfill, were calculated and included in the LCA study.</p><p>The slurry and wet route resulted in net CO2 reduction of 87.4% and 72.3% respectively.  However, a positive contribution to other environmental issues was observed with the wet route leading to higher impact mainly due to high heating requirement. An exception was contribution of slurry route to abiotic resource depletion, which was higher for the slurry route due to high water requirement. A general conclusion was that the electricity consumption is the main cause of environmental issues. Sensitivity analyses showed that the environmental impacts are dependent on the transportation distance and electricity source, while no dependence was observed with respect to construction of the carbonation plant.

As Lithium-ion batteries (LiBs) emerge as pivotal energy storage solutions for automotive applications, maintaining their performance and longevity presents challenges due to power and capacity fade influenced by environmental and usage conditions. Thus, to estimate battery degradation, estimating the state of health (SOH) or predicting remaining useful life (RUL) without considering future operational loads, can limit accurate SOH forecasting. Meanwhile, machine learning (ML) models including deep neural networks (DNNs), have become effective techniques for SOH forecasting of LiBs due to their capability to handle various regression problems without relying on physics-based models. The methodology used in this study, helps battery developers link different operational strategies to battery aging. We use inputs such as temperature (T), current (I), and state of charge (SOC) and utilize a feature transformation technique which generates histogram-based stressor features representing the time that the battery cells spend under operational conditions, then investigate the performance of DNN models along with explainable machine learning (XML) techniques (e.g., SHapley Additive exPlanations) in predicting LiB SOH. The comparative analysis leverages an extensive open-source dataset to evaluate the performance of deep learning models such as LSTM, GRU, and FNN. The forecasting is executed in two distinct modes: one capping the forecasted cycles at 520, and another extending the predictions to the end of the battery’s first life (SOH=80%).Furthermore, this study explores the practicality of a lightweight model, e.g., support vector regression (SVR) model, to compare against DNN models for scenarios with constrained computational and memory resources. The results show that utilizing a feature refinement to ensure the coverage of critical features can lead to performance comparable with the DNN (e.g., LSTM) for the SVR model.

The study aimed to define and investigate relevant parameters affecting manual frequency restoration reserve (mFRR) volumes of the balancing market in the Finnish price area. It also aimed to find suitable models and investigate Day-ahead prediction possibilities of mFRR volumes. Parameters related to mFRR volumes Day-ahead predictions were identified in several earlier studies where of nine parameters were investigated. The correlations between mFRR volumes and the different parameters were investigated using Spearman’s correlation. Different linear machine learning models for Day-ahead predictions of mFRR volumes were builtand tested in Python. The resulting models used for predicting mFRR volumes in Python were one ARIMAX model and one SARIMAX model. The models were validated with a walk-forward method where Day-ahead predictions were conducted monthly for one year. The accuracy of the predictions was measured by the validation parameters Mean Absolute Value, Root Mean Square Error and Median Absolute Deviation. Results from the study show that it is difficult to predict absolute activated mFRR volumes. Although, it might be possible to predict that mFRR volumes will be activated or not, up- or down regulated to some extent. One explanation of the difficulties in predicting mFRR volumes is dueto mFRR being a balancing product whose function is to regulate disturbances in the electricity grid.

Electric vehicles (EVs) are increasing in popularity and play an important role in decarbonizing the transport sector. However, a growing EV fleet can cause problems for power grids as the grids are not initially designed for EV charging. The potential of a power grid to accommodate EV loads can be assessed through hosting capacity (HC) analysis. The HC is grid specific and varies, therefore it is necessary to conduct analysis that reflects local conditions and covers uncertainties and correlations over time. This theses aims to investigate the HC for EVs in existing residential power grids, and to gain a better understanding of how it varies based on how the EVs are implemented and charged. The work is in collaboration with a distribution system operator (DSO) and is based on two case studies using real-life data reflecting conditions in Swedish grids. Combinations of different HC assessment methods have been used and the HC is evaluated based on cable loading, transformer loading and voltage deviation. Additionally, the study investigated three distinct charging strategies: charging on arrival, evenly spread charging over whole connection period, and charging at the lowest spot price.  The results show that decisions on acceptable voltage deviation limit can have a large influence on the HC as well as the charging strategy used. A charging strategy based on energy prices resulted in the lowest HC, as numerous EVs charging simultaneously caused high power peaks during low spot price periods. Charging on arrival was the second worst strategy, as the peak power coincided with household demand. The best strategy was to evenly spread out the charging, resulting in fewer violations for 100% EV implementation compared to the other two strategies for 25% EV implementation.  The findings underscore the necessity for coordinated charging controls for EV fleets or diversified power tariffs to balance power on a large scale in order to use the grids efficiently.