According to the Intergovernmental Panel on Climate Change, an increase in global temperature to above 1.5°C can be halted but would require immediate intervention to reach net zero emissions in the next 15 years. This intervention would have to make use of sustainable energy technologies such as net-zero carbon systems for automobiles. Electric vehicle (EV) use is set to increase 3000% between 2016 and 2030. Due to the inherent toxicity of the chemicals within Li-ion batteries, they must be recycled to be sustainable. Recycling using energy recovering, hydrometallurgical process reduces greenhouse gas emissions. However, due to the high energy and power density within EV batteries, discharging the batteries is an important safety step in the pre-treatment process. There is no industry standard for discharging EV batteries. Many processes are suggested in literature with little information as to the methods used. The aim of this thesis is to explore four processes that could be suitable for industrial use. A suitable process should be ‘safe’, meaning it reduces the risk to the facility by minimizing the fire or explosion hazard, minimizes or eliminates human interaction with the battery pack and limits voltage rebound of an individual cell to 0.5V. The process should also be ‘rapid’, meaning it ensures that discharging does not become a bottleneck in recycling, ‘sustainable’ meaning it has no polluting fluid waste streams and ‘feasible’ that is, is cost efficient. Three processes were found effective. The first, is a combination of salt-solution and metal powder discharge methods using sodium carbonate and steel. This method is intended for battery packs and modules of less than 500V at 0% SOC. The second, is energy recovering electronic load discharge for battery backs greater than 500V or at greater than 0% SOC.  Finally, inductive, wireless discharge with BMS ‘override’ is suggested. This method is suitable for future battery packs of all sizes equipped with wireless charging technology.

The work of this thesis is focused on creating the base for developing new hydraulic systems for mobile machinery tailored for an electric drive system. The loader crane is used as the principal application. With batteries being costly to invest in and having a much lower energy density than diesel fuel, the new systems must significantly reduce the energy consumption compared to the conventional system while keeping the performance in order to enable an electric drive. Exactly how much more energy efficient a new system must be will differ with the use case of the application, and with time, as components and the market develop. The aim is therefore to present a large number of new system concepts with different levels of energy reducing capabilities and complexity rather than proposing a single solution.  In order to be able to evaluate and compare different system solutions, a drive cycle for the working envelope of the loader crane is developed. The drive cycle includes as much variance of the movement as possible in a short time, which is of practical use when testing prototypes.  The task of finding new energy efficient solutions is started by performing a loss analysis on the reference crane. The analysis shows that losses due to simultaneously operated functions are significant, and consequently that multi-pump systems are of interest. A concept study that looks deeper into multi-pump systems as well as other loss-reducing concepts is carried out, and a large number of new system solutions with different energy reducing potential are presented.  A promising concept is the two-pump system with open flow control, which is investigated in more detail by building and testing a prototype. The results from operation of the prototype highlight the challenge of achieving smooth control, but also that the efficiency is indeed improved compared to the refer-ence system.  As this work is part of a larger research project, studies have been conducted on other interesting concepts as well, but with different applications. Results from these that are relevant to the loader crane case are discussed together with the results from the studies included in this thesis, in order to give a broad view on how a suitable system can be selected for the intended application. / <p>2023-04-14: ISBN (PDF) has been added in the E-version.</p>

This bachelor's thesis explores the potential of Skolfastigheter's facilities to achieve self-sufficiency through solar power while maintaining economic feasibility. The study specifically examines the economic feasibility of various solar power installation sizes, while also exploring key characteristics of school facilities that influence their level of self-sufficiency. To assess this, the report is structured into several steps. The initial step involves identifying properties with the potential to achieve Skolfastigheter's objective of being 15 % self-sufficient and subsequently ranking them. The following step involves evaluating the maximum potential self-sufficiency of a few selected properties through an optimization problem, with an upper limitation in investment cost and maximal capacity. Once optimal self-sufficiency is detected and evaluated a sensitivity analysis is conducted to test the model's robustness by considering different electricity prices and orientations. The results indicate that fluctuating electricity prices have a significant effect on the potential size of the solar panel system, while the orientation has a minor effect when optimizing for self-sufficiency. The key characteristic for achieving optimum self-sufficiency is an even consumption pattern throughout the year, and the facility size is mainly dependent on the current electricity pricing. Furthermore, it is highly probable that the current 15% self-sufficiency threshold for Skolfastigheter AB can be surpassed.

A society with interconnected energy sectors may be a contributing factor to reduce carbon dioxide emissions, while simultaneously meeting the increasing demand for electric energy. This study investigates the possibilities to link a sea-based wind farm with hydrogen gas production in addition to serving as a support function to a transmission systems operator. Using a custom-built model, this interconnected system is simulated for different scenarios where the wind farm, electrolyser and the balanced power market are observed. The model takes into account the economic potential and the different ways of producing hydrogen gas, while also discussing the potential significance of interconnected systems such as this.  The result indicated that the economic viability in constructing an interconnected system such as the one included in the study is substantially dependent on the variability of the price for electricity. It is also concluded that out of the modelled scenarios, two could be considered to have the possibility to become economically viable. One case consisted of an electrolyser being fed electric power directly from the wind farm, where the system was constantly available to act as a support system to the power grid. The other scenario considered viable based on the results was when the electrolyser was fed with electric power from the grid and set to be available to run while the spot price was below a threshold value.  While the parameters used for sizing the system in the model cannot be considered to be optimized in all cases, the size of the electrolyser did not significantly affect the result of the simulated scenarios.

This bachelor thesis will examine the actions that have been taken to lower the electricity use at Uppsala University Hospital during the winter of 2022/2023. To be able to evaluate the changes that have been done there will be a comparison between the winter of 2022/2023 and the winter of 2021/2022. During the recent winter Uppsala University Hospital made two different types of changes to make the electricity use decrease. Firstly, they continued with implementing technical changes which involves for example switching regular lights to LED-lights and ensuring that fans are operating efficiently. Secondly, they sent out information to every department through their website, newsletters, and other information sources. They also urged every department’s environment coordinator to spread awareness about the energy crisis and how to save electricity by creating behavioral changes as well. It was discovered that Uppsala University Hospital lowered their electricity use by 5,62% the winter 2022/2023 compared to the winter 2021/2022. However, the result that was concluded from this project was that it was quite difficult to distinguish how much behavioral changes contributed to the decrease. The only time it was possible to distinguish this was when bigger actions were taken, for example turning of the sauna. In most cases it was the technical changes that contributed the most to the decrease of electricity use.

To tackle the global sustainability challenge, the energy system needs to transition towards a sustainable system, since it is responsible for two-thirds of global greenhouse gas emissions. To reduce emissions researchers urged for a 100% renewable based energy system, in which photovoltaic (PV) energy production is seen as a key component. Social aspects should be considered and participation from individuals is needed. This thesis aims to answer the question“How can small-scale photovoltaics (SSPV) contribute to a transition towards a sustainableenergy system?” The case of Austria and Sweden. This thesis conducted 10 in-depth semistructured qualitative interviews from each country, applying PESTLE framework in coding. Results were assessed through a unique combination of Backcasting as a lens, eight Sustainability Principles (8 SPs), and PESTLE. SSPV enables individual contribution to the energy transition. SSPV has a limited role to play in the energy system in Austria, but even more limited in Sweden. Both countries are currently overwhelmed with the demand for SSPV. Since SSPV is not sustainable according to the 8 SPs the method of Backcasting should be repeatedly applied for SSPV to assess if this trend is truly contributing to a sustainable energy system.

Transitioning to circular flows is essential to economize the planet’s resources. One of the most important resources on earth is water as it is vital for all living things. However, water purification methods have proven to be very energy intensive, and increasing the circular water flows is therefore challenging. Volvo Construction Equipment (VCE) in Hallsberg is a manufacturing industry that produces cabs and tanks for VCE’s machines. The factory needs a lot of water in the pre-treatment process, and a falling film evaporator is currently used to purify most of the process water. VCE is considering investing in another evaporator to add to the existing water treatment system as a second stage to concentrate the process water further. The aim of this project was to investigate how to increase the energy efficiency of the water treatment system at VCE in Hallsberg and the planned extension of that system. The aim was also to analyze the water treatment system as it is today to get a better understanding of the current situation. The method was divided into two main parts. First, the current water treatment was investigated through measurements of electricity, temperatures and mass flows. A few mass and energy balances were also set up, and the excess steam recirculation of the current evaporator was investigated. Secondly, an investigation of potential future water treatment systems was made. The second part consisted of a comparison of different types of evaporators and combinations of these with a focus on energy performance and technical aspects. The second part also included investigating which heating and cooling sources could be used if the second-stage evaporator was to be running on waste heat. The result showed that the electricity demand of the water treatment facility at VCE Hallsbergis approximately 72.7 kWh/ m3 distillate. Measurements also showed that the falling film evaporator used today purifies approximately 0.71 m3/h. Furthermore, the results showed that only 3 % of the energy demand in the falling film evaporator could be exchanged to waste heat, and the waste heat would need temperatures of 100 °C or above. In a second-stage evaporator, the waste heat could be used to replace a larger proportion of the electricity use. There is sufficient power from the ovens to be used as waste heat in the second-stage evaporator. District heating could also be used as a heat source, but only for the low-temperature evaporator. For cooling, a new source would be needed where a compromise between energy use and water consumption of the cooling system needs to be made. This thesis is our degree project for the master of science in energy-environment-management atLinköping University. The project was carried out during the spring semester of 2023.

In Sweden, district heating is the most common way to heat apartment buildings and premises. It is most common for properties to use district heating as the only heating source, but there are now trends in which more and more properties combine district heating with another energy source such as an exhaust air heat pump or geothermal heating. This report is a case study on how an exhaust air heat pump can be combined with district heating in an apartment building compared to if the house uses only district heating for heating. The background to the study is that Gävle Energi AB wants to investigate the return temperature to the district heating network from a facility that has an exhaust air heat pump and district heating in combination compared to a normal facility that only has district heating. The focus of this thesis is on investigating two structurally identical properties in Gävle with two different ventilation systems and heating systems. The first property, Property 1, has an exhaust and supply air ventilation system with a heat exchanger and only district heating for heating. The other property, Property 2, has a mechanical exhaust air ventilation system with exhaust air heat pump and district heating in combination. The method used during the analysis has been a compilation of collected data from Gävle Energi AB and of own measurements with a measurement period of one week. The analysis compares two different heating systems based on three different factors, energy use (kWh), supply and return temperature to the district heating network (°C) and operating costs (SEK/Year). Results show that, Property 2 (exhaust air heat pump in combination with district heating) has 31% lower district heating use on average. However, electricity uses for the property increased by 20%. The total energy use for property 2 was thus reduced by 15%. The reduction in energy use in Property 2 corresponds to a reduction in operating costs of 5.4%.However, the operating cost of Property 2 does not include the investment in the heat pump or the maintenance cost. Both the investment in the district heating center and the maintenance cost are included in the district heating price. COP calculated varying between 1.8 and 3.8. COP measured varied between 2.2 and 3.8. COP value for Property 2 was 3 on average for both COP measured, and COP calculated.   District heating in combination with an exhaust air heat pump gives a higher return temperature than district heating alone, the difference was about 10 °C during the measurement carried out for a week in April 2022. The difference was also verified by the volume-weighted return temperature, which was calculated to be 1.0 °C higher. The conclusion is that an exhaust air heat pump in combination with district heating seems to have a lower operating cost resp district heating and mechanical supply and exhaust air with heat recovery ventilation for the user in the studied types of building, but it also creates an elevated return temperature in the district heating network. Environmentally, an exhaust air heat pump together with district heating can be positive if electricity is produced from renewable energy sources with low carbon dioxide emissions, such as solar energy and wind power, but consideration must be given to system effects in the district heating network, such as how the production of electricity is affected, this varies between different district heating systems.

The aim of this master thesis is to design and analyze a photovoltaic (PV) system with the smallest possible carbon footprint. The system will be located in Borlänge, Sweden near the airport. The main components the analysis will focus on are the modules, inverters as well as the cabling. For that, different technologies like thin film and crystalline silicon cells will be compared with each other in order to find out how much the energy consumption in production differs. Since carbon emissions depend on the electricity mix, the manufacturer will also be included in the analysis. That way, manufacturers that use highproportions of renewable energies can produce products with a small carbon footprint, even if the energy demand is comparatively high. The last phase, will focus on factors such as warranties, because longer lifetimes also help to reduce the carbon footprint. For the analysis two software are used. The Granta EduPack, which has data on the carbon emissions for different materials and therefore is used to estimate carbon footprints for some of the components. As well as PVsyst, a software to simulate PV projects. It is used to scale the components and also to get an estimate for the annual yield and its deviation. The analysis finds that even in Sweden, a carbon footprint (CF) of just 14 g/kWh can be achieved. This value is 70 percent below that of today's average utility scale PV system. Considering the margin of error, it is assumed that this value could be as low as 11 g/kWh under optimal conditions and up to 23 g/kWh in the worst case. This puts the CF in the same range as on- and offshore wind power. For better suited locations such as near the equator, this value could be more than halved. With these values, PV is already one of the lowest emitters of greenhouse gases (GHG) among power generation technologies. It can be assumed that these values will continue to fall. Due to process optimization and an increase in efficiency, the carbon footprint of both modules and inverters is reducing steadily. This thesis is written in cooperation with two Energy Efficient Built Environment (EEBE) students, who in addition analyze the mounting structure of the system. The aim for the mounting structure is to have a low carbon footprint as well. Their results on the different structural materials are integrated in the conclusion.

The goal of this project was to construct a model of a microgrid to avert possible power disruptions. The microgrid should provide electrical energy to four essential facilities; a nursing home, a gas station, a preschool and a fire station. The simulations were performed on the assumption that the microgrid is self-sufficient and thereby has its own energy production and storage. The potential of the solar cells, as an energy source, was investigated in the simulation model. A biogas turbine was considered to compensate for the months when the energy production is less than the demand.  Energy storage in the form of a lithium-ion battery was also included in the simulation model. The battery was designed to operate immediately after a power outage. According to the simulations, the installed solar cells did not generate enough electrical energy to satisfy  the energy needs in the facilities during autumn, winter and spring. If a storm strikes during these seasons, Knutby will have insufficient power. The system has been deemed insufficiently resilient when the system is off-grid. However, if this system is combined with a backup power source, it will be more resilient. The solar cells would provide electrical energy during the summer and the backup power supply would handle any emergency situations during the rest of the year. Biogas is produced locally at Kungsängens gård and will therefore make the system more resilient  If the aim and/or use of the microgrid were to be changed, the choice of energy production and energy storage might be altered to satisfy the given purpose.