With the growing acceptance of photovoltaic (PV) systems globally including Sweden, an increasing number of PV systems has continually been installed all through Sweden. In this study, a selected residential area in Uppsala Sweden is considered as a possible site for PV system installation. Due to the intermittent nature of this energy source and the disturbances it causes to the grid, there is therefore the need to determine the amount of PV that can be accommodated by the already existing grid without any adverse effect to it. This is known as hosting capacity (HC). The HC signifies the level of risks the network operator as well as customers are willing to take with regard to the stability of the grid network. Many possibilities exist by which this can be done which are well discussed later in this report. However, the deterministic method is used in this work. For an effective determination of the HC, the DIgSILENT Power Factory 2021 is used to simulate a synthetic network assumed to be similar to that of the area studied. A parametric analysis is also done to as certain the impact some network variables would have on the limit of PV systems a grid network can accommodate. The results of the study showed that under 0 % penetration, the grid network is stable and no violations witnessed neither from the network with 800 kVA transformer considered as the main network in this study nor that with 500 kVA used for the parametric studies. However, the loadings on the two transformers varied by about 15 %. Integrating PVs into the grid network introduced some level of instability which increases as the size of the PVs increases. This shows the need to peg the PVs’ size to a certain maximum to be able to have control over the grid network. Customers are allowed to install lower sizes but not more than this maximum. The results also showed that changing the transformer size do not affect the nodal voltages nor the cable loadings in the network provided all other parameters remained the same. The only impact is on the transformer loading, with smaller transformers experiencing higher loading condition. This study serves as a basis to determine the initial range of PV sizes customers are allowed to install in the area studied in Uppsala Sweden.

Ett viktigt steg vid tillverkningen av ett energieffektivt och hållbart trädbränsleär torkning. Torkprocessen är energiintensiv och kan uppgå till så mycket som en fjärdedel av trädbränslets totala produktionskostnad. En både låg och jämnt fördelad fukthalt är en avgörande faktor för bränslets kvalitet och vidare användning. Det i sin tur ställer höga krav på en energieffektiv torkprocess som producerar ett bränsle med önskad kvalitet. För att vidare bidra till forskningen inom torkning av trädbränslen har en laborativ ångtorkanläggning med fast bädd byggts på Karlstads universitet. En tidigare studie har gjorts på torkanläggningen där träflis ångtorkades. I resultatet av studien visade det sig förekomma oönskade fuktvariationer i den torkade flisen till följd av en ojämn flödesbild. Flödesbilden beskriver hur ångflödet sprider sig genom flisbädden och är en viktig faktor för en jämn torkprocess och torkanläggningens effektivitet. Syftet med studien är att effektivisera torkanläggningen genom att förbättra flödesbilden, samt fastställa hur torkanläggningen bör köras för att säkerställa en produktion av ångtorkad flis med en jämnt fördelad fukthalt. Temperaturmätningar på flisbädden gjordes under drift och användes som underlag för att bestämma hur torkanläggningen bör byggas om för en jämnareflödesbild. Den ombyggda torkanläggningen utvärderades med avseende på energianvändning, SMER och slutlig fuktvariation i den torkade flisen. Utifrån torkförsök med olika driftförutsättningar på ångflödets dynamiska tryckstegring, ångtemperatur och bäddhöjd fastställdes ett rekommenderat driftfall. Genom att montera en perforerad plåt framför flödesinloppet till torkkammaren på torkanläggningen kunde torkkammarens uppvärmningstid minskas med 5 minuter. Vidare reducerades energianvändningen med 11%, samtidigt somSMER ökades med 14% i förhållande till före ombyggnation. Fuktvariationeni flisbädden reducerades från 21% till 8%. Rekommenderad drift fastställdes till en dynamisk tryckstegring på 200 Pa, en ångtemperatur på 180˚C och 100mm bäddhöjd. / An important step in the production of an energy-efficient and sustainable wood fuel is drying. The drying process is energy demanding and can amount to as much as a quarter of the wood fuel's total production cost. A both low and evenly distributed moisture content is a decisive factor for the quality of the fuel and its further use. This in turn places high demands on an energy-efficient drying process that produces a fuel of the desired quality. To further contribute to the research in the drying of wood fuels, a laboratory steam drying plant with a fixed bed has been built at Karlstad University. A previous study has been done on the drying plant where wood chips were steam dried. The results of the study showed undesirable moisture variations in the dried wood chips as a result of an uneven flow pattern. The flow pattern describes how the steam flow distributes through the bed of wood chips and is an important factor for an even drying process and the overall efficiency of the drying plant.The purpose of the study is to increase the efficiency of the drying plant by improving the flow pattern, and to determine how to operate the drying plant to assure a production of steam-dried woodchips with an evenly distributed moisture content.Temperature measurements on the wood chip bed were made during dryingexperiments and were used as a basis to determine how to rebuild the drying chamber for a more even flow pattern. The rebuilt drying plant was evaluated regarding energy use, SMER and final moisture variation in the dried woodchips. Based on drying experiments with different operating conditions on the dynamic pressure rise of the steam flow, steam temperature and bed height, a recommended operating case was determined. By placing a perforated plate in front of the flow inlet to the drying chamber of the drying plant, the preheating time of the drying chamber could be reduced by 5 minutes. Furthermore, energy use was reduced by 11%, while SMER was increased by 14% compared to before the rebuild. The moisture variation inthe wood chips was reduced from 21% to 8%. Recommended operation conditions were set at a dynamic pressure rise of 200 Pa, a steam temperature of 180˚C and 100 mm bed height.

I Sverige kommer största delen av producerad el från förnybara källor men solenergin står i dagsläget för ett litet bidrag till den svenska elproduktionen. Energipolitiska mål gör gällande att Sverige ska ha 100% förnybar elproduktion år 2040. I dagsläget är industrisektorn en av huvudkonsumenterna av elektriciteten i Sverige. Industrifastigheter lämpar sig ofta väl för takmonterad solcellsinstallation. Genom energieffektiviseringar och användning av förnybar el kan företag reducera sina elkostnader och sin miljöpåverkan. Överproduktion av el från solcellsanläggning kan dessutom generera inkomster från såld solel. Målet med arbetet var att förse industriföretaget Springwire Sweden AB med jämförande energi-, ekonomi- och miljöanalys för olika investeringsscenarier av solcellsanläggning och/eller LED-belysning för att presentera investeringen med bäst lönsamhet, kortast återbetalningstid samt störst miljöpåverkansreduktion. Föreslagna scenarier undersöktes med avseende på energiflöden, ekonomisk genomförbarhet samt miljöpåverkan och jämfördes med företagets nuläge med hjälp av energikartläggning, kostnads-/intäktsanalys och livscykelanalysmetoder. Med hänsyn till rådande skatteregler för solcellsanläggningar begränsades största enskilda undersökta solcellsanläggning till 500 kWp. Springwire förfogade över två fastigheter vilka båda kunde husera varsin 500 kWp-anläggning på taket och därför undersöktes installation av 500 kWp-anläggning på båda fastigheternas tak (500+500 kWp). De ekonomiska resultaten visade att solcellsanläggningen 500+500 kWp kombinerad med LED-belysning var den mest lönsamma investeringen av de undersökta investeringsfallen under antagna ekonomiska livslängden 30 år. Nettonuvärdet, investeringens lönsamhet, för 500+500 kWp-anläggningen kombinerad med LED-belysning var 10 MSEK. LED-belysning var investeringen med kortast återbetalningstid, 2,5 år. Investeringen 500+500 kWp kombinerad med LED-belysning minskade koldioxidavtrycket för företagets produkter med 24% jämfört med nuläget. Det innebar att miljöpåverkan för varje ton ståltråd minskade med 19,5 kg CO2e vilket med hänsyn till företagets totala ståltrådproduktion per år motsvarade minskning med 80 ton CO2e. Studiens resultat visade att genom att investera i solcellsanläggning och/eller LED-belysning kan industriföretag inom ståltrådproduktion öka sin ekonomiska lönsamhet över tid och samtidigt minska miljöpåverkan från sina produkter. / In Sweden, most of the electricity produced comes from renewable sources, but solar energy still accounts for a small contribution to the Swedish electricity generation. Energy policy goals state that Sweden will have 100% renewable electricity production by 2040. Currently, the industrial sector is one of the main consumers of the electricity in Sweden. Industrial properties and buildings are often well suited for roof-mounted photovoltaic system (PV system) installation. Through energy efficiency improvements and the use of renewable electricity sources, companies can reduce the corresponding energy costs and the environmental impacts. Overproduction of electricity from PV systems can also generate income from sold solar electricity. The aim of this work was to provide the industrial company Springwire Sweden AB with comparative energy, economic and environmental analysis for different scenarios on the investment in PV systems and/or LED-lighting to present the investment with the best profitability, shortest payback period and largest environmental impact reduction. The proposed scenarios were investigated in terms of energy flows, economy feasibility and environmental impacts, and were compared with the current energy sources in the company using energy mapping, cost-benefit analysis and life cycle assessment methods.  Regarding the current tax rules for PV systems, the largest individual investigated PV system is limited to 500 kWp. Springwire has two properties where each building could be host of a 500 kWp plant on the roof and therefore the installation of a 500 kWp PV system on the roof of both properties (500+500 kWp) was investigated. The economic results shows that the PV system 500+500 kWp combined with the LED-lighting is the most profitable investment over the assumed economic lifetime of 30 years between all the proposed scenarios. The net present value was found to be SEK 10 million for the 500+500 kWp PV system combined with LED-lighting. LED-lighting was the investment with the shortest payback period, 2.5 years. The investment of the 500+500 PV system combined with LED-lighting would reduce the carbon footprint of the company's products by 24% relative to the current scenario. It means the climate impact of each ton wire would decrease by 19.5 kg CO2 eq, and considering the total amount of the company production per year, this value would be 80 ton CO2 eq.  The results of the study revealed that by investing on photovoltaic systems and/or LED-lighting, industrial companies on wire production can increase their economic profitability over time while reducing the environmental impact of their products.

Energy efficiency of buildings is becoming more and more common as a step towards decreasing the amount of climate emissions in the world. In the Swedish city Gothenburg, there are many existing buildings that soon faces extensive renovations due to age and therefore they have a lot of potential to, at the same time, improve the energy efficiency. Some of the buildings uses district heating as heating system and therefore this project has included an investigation of how the energy efficiency of a building affects the delivery of the district heating. The project also included an investigation of how energy efficiency of existing buildings affects the planning of the future needs of district heating.By applying energy saving measures on a reference building that can represent all the buildings in an area can the maximal power use at the DVUT be forecasted. The energy savings impact on the building’s energy- and power signatures is also a part of the study. The result of the energy savings measures is then used in an example of Gothenburg´s urban development by applying the results of the reference building on an area called Heden.The project includes a study, a model in VIP-Energy, an economic analysis of the energy savings and the example of the urban development of Heden. The results shows that the suggested measures reduce the primary energy number by 47 % and that the maximal power use reduced by 50 %. For property owners the economic analysis showed that the measures were not enough profitable. On the other hand, did the result, by the example with Heden also showed that Göteborg Energi can profit by reducing the energy use in existing buildings because it reduces the future additional net power.

A method of providing ventilation using impinging jets (IJV) utilizes stratification while delivering air at a high velocity. As a result of this attribute and the simplicity of its terminal construction, IJV offers an advantage over the well-known Displacement Ventilation (DV) system. The corner IJV system was used during this investigation to construct the Computational Fluid Dynamics (CFD) simulation protocol. To verify the suitability of the turbulence model used in the CFD simulation, numerical values derived from several turbulence models were compared to full-scale experiment data. The results of this study demonstrate that turbulent models are the most important factors when using CFD for the study of the velocity field generated by IJVs terminals. A parametric study was conducted after the models were created and verified using the CFD software COMSOL to determine which is the most suitable arrangement for occupants' ventilation and draught avoidance in a square room. Calculations using computational methods were conducted to characterize the rooms' performance under different operating conditions and cross-sections of the air supply terminals. Among the findings of the research is that increasing the cross-section of the supply terminal reduces the sensation of local discomfort, but decreases air velocity speeds. Furthermore, placing the supply terminal on the same side of a room block improves occupant satisfaction, whereas placing the supply terminal on opposite sides enhances ventilation efficiency.

With the need to reduce CO2 emissions in the energy sector, ensure electric grid stability and reduce future cost uncertainties for process cooling, solar cooling can be an interesting solution. This report describes the comparison of solar cooling with either a photovoltaics system or a solar thermal system using a thermally driven chiller. The application investigated was industrial process cooling, for three load profiles and three locations in Europe. The method of comparing was by simulations in TRNSYS and calculation of the global levelized cost of cooling, taking into account the total cost of covering the whole cooling demand. The results for the global levelized cost of cooling showed that solar thermal cooling was not economically competitive compared to the reference system or the photovoltaic cooling system for any of the investigated boundary conditions. The general trend was that the global LCOC for the solar thermal cooling increased with the solar cooling fraction. The photovoltaic solar cooling system global LCOC was in parity with the reference system for low SCF of 20 % to 30 %, and even up to 60 % for some boundary conditions.

The European Commission´s regulation on requirements for grid connection of generators, RfG, came into force in 2016. The regulation establishes a network code which lays down the legally binding requirements for grid connection of power-generating facilities. However, these requirements have been shown challenging to implement in the Swedish power system industry. The aim of the thesis was to identify obstacles for handling RfG and to contribute to the understanding of what challenges the regulation faces in the Swedish power system industry. To gain an understanding of how different stakeholders perceive and adjust to the requirements, interviews were performed with several representatives from each affected group of stakeholders. The affected parties agree on the necessity of regulations for grid connection of power generating facilities. Still, it became clear that lack of organizational structure and expertise among several stakeholders hinder the establishment of effective processes handling RfG requirements. The challenges that surfaced were not solely organizational. It was pointed out that how the regulation allows for interpretation is challenging since there is inadequate national practice in place. In some cases, the Swedish power system industry has managed to establish this practice, while in other areas, there is still need for clarification. In conclusion, RfG provides necessary requirements for grid connection of power-generating facilities, but it also challenges involved stakeholders in their work. Facilitating the continued implementation of RfG in the Swedish power system requires organizational development, as well as the establishment of industry-wide practices in areas perceived as ambiguous. This thesis has gathered insights from various stakeholders and can be used as an indication of areas in need of further development when working with the RfG requirements.

According to U.S. Department of Energy, offshore wind energy has the potential to generate 7,200 TWh of energy annually, which is nearly twice the current annual energy consumption in the United States. With technical advances in the offshore wind industry, particularly in the floating platforms, windfarms are pushing further into the ocean. This creates new engineering challenges for transmission of energy from offshore site to onshore. One possible solution is to convert the energy produced into chemical energy of ammonia, which was investigated by Dr. Eric Morgan. In his doctoral dissertation, he assessed the technical requirements and economics of a 300 tons/day capacity ammonia plant powered by offshore wind. However, in his dissertation, one of the assumptions was connection to the grid which provided auxiliary power to keep the ammonia plant operational and produce at rated capacity. It also allowed selling of excess power to the grid in the scenario of excess power production by wind farm during high winds. This thesis explores the technical and economical feasibility of a similar system, except that the ammonia plant will be on a plantship and there is no connection to the grid. This creates a challenge as the ammonia synthesis plant must operate between 65-100% loads. Thus, the concept of multiple mini-ammonia plants is used to address the scenario of wind energy production at less than rated power. This will allow operation of one or more mini-ammonia plant (corresponding to the available energy from offshore wind). In the event of wind speed lower than the cutoff wind speed for the turbine, the ammonia plant will use the produced ammonia as fuel, with the help of a gas turbine running on either Brayton cycle or combined cycle, to keep the plant idling. It will maintain the reaction conditions of the synthesis chamber and will not produce any ammonia. This is an important step as it takes days to reach the reaction conditions to start ammonia production again after shutting down due to unavailability of energy at low winds. Thus, at any windspeed, a mini-ammonia plant would either idle or operate between 65-100% load. This model will be used to simulate the total energy consumption, total energy captured by the wind farm, and the total ammonia produced. This will further help in assessing the final cost of producing, transporting, and consuming ammonia as fuel and thereby provide a better understanding of the feasibility of implementing this technology. According to U.S. Department of Energy, offshore wind energy has the potential to generate 7,200 TWh of energy annually, which is nearly twice the current annual energy consumption in the United States. With technical advances in the offshore wind industry, particularly in the floating platforms, windfarms are pushing further into the ocean. This creates new engineering challenges for transmission of energy from offshore site to onshore. One possible solution is to convert the energy produced into chemical energy of ammonia, which was investigated by Dr. Eric Morgan. In his doctoral dissertation, he assessed the technical requirements and economics of a 300 tons/day capacity ammonia plant powered by offshore wind. However, in his dissertation, one of the assumptions was connection to the grid which provided auxiliary power to keep the ammonia plant operational and produce at rated capacity. It also allowed selling of excess power to the grid in the scenario of excess power production by wind farm during high winds.\\ \par This thesis explores the technical and economical feasibility of a similar system, except that the ammonia plant will be on a plantship and there is no connection to the grid. This creates a challenge as the ammonia synthesis plant must operate between 65-100\% loads. Thus, the concept of multiple mini-ammonia plants is used to address the scenario of wind energy production at less than rated power. This will allow operation of one or more mini-ammonia plant (corresponding to the available energy from offshore wind). In the event of wind speed lower than the cutoff wind speed for the turbine, the ammonia plant will use the produced ammonia as fuel, with the help of a gas turbine running on either Brayton cycle or combined cycle, to keep the plant idling. It will maintain the reaction conditions of the synthesis chamber and will not produce any ammonia. This is an important step as it takes days to reach the reaction conditions to start ammonia production again after shutting down due to unavailability of energy at low winds. Thus, at any windspeed, a mini-ammonia plant would either idle or operate between 65-100\% load. This model will be used to simulate the total energy consumption, total energy captured by the wind farm, and the total ammonia produced. This will further help in assessing the final cost of producing, transporting, and consuming ammonia as fuel and thereby provide a better understanding of the feasibility of implementing this technology.

To enable the transition to a fossil-free society and ongoing urbanization, where new establishments emerge in the heart of the society, the Swedish electricity system faces new challenges. Building a new powerline to meet the increased power demand is an expensive process, and in an existing grid, there isn’t always room to build new power lines. This leads to a capacity shortage at the local level, fundamentally due to the grid being undersized in areas where there are old power lines with lower rated current. To meet the increased power demand that electrification entails and simultaneously make capacity available for new establishments within the existing grid infrastructure, the potential of energy storage is being evaluated against the traditional solution of building new power lines. The purpose of the present work was therefore to investigate whether energy storage can be a potential solution to make capacity available for future establishments in an area where there is a capacity shortage. The energy storage solutions were evaluated from an economic, environmental, and power quality perspective and compared to building a new power line. This was done from the perspective of a grid company, where neither the market of frequency stability nor the electricity price market were included in the analysis. Based on the existing theory of energy storage, battery storage was chosen as the potential solution. To narrow the scope of the work, an area in Piteå Municipality was selected where a new establishment demands a power with drawal of 3 MW and is located midway between two existing grid lines. Using one year of operational data for the affected grid lines and calculations of their rated current, the performance of the battery storage was simulated, evaluating different battery sizes and energy contents (C-rate). Since the Electricity Act does not allow grid companies to own energy storage, the economic aspect was evaluated based on two different cases of battery rental. The goal is to maintain redundancy with the adjacent grid line with the additional power with drawal of 3 MW, to manage a potential outage without extensive consequences for subscribers. The results of the calculations and simulations show that the current grid line can handle the extra 3 MW requested. However, the battery storage does not relieve the grid sufficiently to prevent exceedingthe maximum capacity of the grid during high loads while maintaining redundancy with the interconnected grid line. The battery storage needs to be larger than 3 MW to relieve the grid as required, which is not economically justifiable. Depending on the rental conditions of the battery storage and which revenues are considered, the profitability of battery storage varies, but with a battery size over 1 MW, regardless of rental conditions, it is not economically justifiable compared to a new power line, which has a significantly longer technical lifespan. For battery storage to be useful in the grid and make capacity available, the grid must have spare capacity. The results also show that the relationship between the size of the establishment and the size ofthe battery storage is not one-to-one, instead, the energy content of the battery storage must be significantly larger to cut the power peaks. An energy content of two times the power, for example, 1 MW and2 MWh, is required for the battery to be advantageous and generate load savings on the grid. However, the battery storage can still relieve the grid to some extent by helping to distribute the current load more evenly, which means that the rated current, which is the limiting factor for short power line lengths, is not exceeded as early.

In 2019 EU introduced new regulations on the energy market and frameworks for new energy initiatives by introducing the Clean Energy Package. The package aims to serve as a framework for how member states promote renewable energy, increase energy efficiency, and create a more integrated and sustainable energy market. One of the frameworks introduced is energy communities. As the trend shifts from centralized and fossil-fueled systems to decentralized systems with increasing renewable energy production, new challenges have arisen for the electrical system. These challenges require innovativeenergy solutions, such as energy communities. Energy communities are a way to provide organizational frameworks for collective energy initiatives. Energy communities involve local stakeholders connecting nearby buildings into a smaller electrical system where they can produce, share, and store energy. Enköping municipality is interested in exploring the potential of energy communities within their new urban districts called Norra Myran and Aros Park. In this thesis, the driving forces and barriers among stakeholders to initiate and operate an energy community in Norra Myran and Aros Park are studied. The selected stakeholders within the thesis are: Enköping municipality, politicians, property developers, landowners, and electricity companies. The empirical data is collected through a qualitative approach built on qualitative observations and interviews with the stakeholders. The analysis is based on the empirical data, contextualized within a theoretical framework built upon previous research on energy communities. The analysis adopts a sociotechnical approach, which involves analyzing technical, social, and legal factors. To understand the potential development paths in Enköping municipality and achieve positive outcomes, it is essential to understand how the factors within the sociotechnical system of energy communities integrate and influence each other. The thesis concludes that the driving forces and barriers among the stakeholders in Enköping to initiate and operate an energy community can be summarized in four aspects. Identified driving forces are summarized as: Energy-and innovation interest, Energy and climate goals, Renewable energy, and Active consumer. Identified barriers are summarized as: Identification of “why”, roles and responsibilities, collaboration model, and laws and regulations.