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  • 1. Aalhuizen, Christoffer
    Potential of V2G in a Rural Low-Voltage Grid on Gotland for Voltage and Power Capacity Control2019Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The Swedish transportation sector needs to undergo major changes in order to achieve the established goals for climate and environment. The largest change is the replacement of fossil-fuelled vehicles to vehicles propelled by renewable energy sources, such as biofuels and electricity. To account for an increase in local electric power consumption, the electric power infrastructure of Sweden needs to adapt through expansion and reconstruction of the electric power grid. However, changes in infrastructure are usually expensive. It is therefore suitable to also examine alternative solutions, which could potentially be more cost efficient. One of these solutions are vehicle-to-grid (V2G), where electric vehicles acts as local electric power control and provides auxiliary services to the electric power grid. This thesis is a case study of a part of a low-voltage electric power grid on Gotland, with the goal of analysing the potential of V2G in the investigated area. The study focused on utilizing V2G for balancing electric power consumption and generation, and for adjusting voltage levels. Simulations of the area were executed in PSS®E for three different cases; one high-load case, low-load case and average-load case. It was found that by utilizing V2G a ramp up of electric power during mornings was delayed by approximately one hour, making the electric power grid potentially more compatible with photovoltaics (PV). However, the overall effects from V2G was fairly low. This outcome can partly be explained by the assumptions made in the report, and also due to some odd behaviour of the system model. 

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  • 2.
    Abrahamsson, Curt Johan David
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Pérez-Loya, Jesús José
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Fregelius, Martin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Evestedt, Fredrik
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Bladh, Johan
    Lundin, Urban
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Magnetic thrust bearing for a 10 MW hydropower generator with a Kaplan turbine2018Conference paper (Refereed)
  • 3.
    Abran, Eszter
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Electricity.
    Andersson, Elin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Electricity.
    Intäktsanalys av vindkraft som reglerresurs: Med och utan batterilager2023Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In order to ensure a stable power system, a balance between production and consumption at every given moment is necessary. An indication of this balance is the system frequency, which deviates from its nominal value in case of imbalance. With an increasing share of weather dependent energy in the Nordic synchronous system, such as wind power, the need for stabilizing services are becoming even more crucial. Ancillary services are a way of keeping the frequency stabilized, they are provided by different actors in the power system with flexible production or consumption. This contributes to increasing or decreasing the input and output of energy to the system when needed. Ancillary services are procured in separate markets that are structured and designed by the transmission system operator, Svenska kraftnät.

    This thesis investigates wind power and its potential of providing ancillary services in the Swedish power system. The report presents two different studies which are performed based on two specific wind farms in Sweden. Firstly, the possibility of providing ancillary services by the wind farms alone are considered with emphasis on the economic profitability. A model is used to present a theoretical maximum of income based on historical production and market data from 2022. The second study has an additional aspect of combining the wind farms with a battery energy storage system (BESS), creating a hybrid system, to examine the potential improvement of income for the company. Due to the production being dependent on weather conditions, the BESS can provide additional contribution when needed. The second study is performed using an optimization model in order to optimize the use of the BESS for the simulated period.

    The results presented an increase of revenues when participating on the ancillary service markets for both studies. The first study showed that down regulating services were the most profitable, this being FCR-D down and aFRR down. With the hybrid system, the profitability was even more significant. It demonstrated a big potential of participating on the FFR market during the summer and FCR-D during winter. Furthermore, the hybrid system also showed an increase in participation on the up-regulating markets. Without the BESS, the windfarm is forced to curtail production toparticipate in the up-regulating markets, which proved to be less profitable than participating on down-regulating markets. The results also give an understanding of the cycling of the BESS and how this affects the results and the BESS lifetime. With coming market development, the conditions on the ancillary service markets is expected to change, the effect of this is considered in a sensitivity analysis. Finally, the studies collectively show the opportunity for wind power to contribute to stabilizing the power system and ensuring the security of energy supply in the Nordicsynchronous system.

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  • 4.
    Abran, Eszter
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Civil and Industrial Engineering.
    Andersson, Elin
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Civil and Industrial Engineering.
    Nilsson Rova, Therese
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Civil and Industrial Engineering.
    Battery Storage for Grid Application: A case study of implementing a Lithium-ion storage system for power peak shaving and energy arbitrage2021Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Large scale Lithium-ion battery energy storage systems (BESS) for stationary power grid application is a developing field among energy storage technologies. Predictions indicate an increased use of the technology which offers a solution to the challenges that the increasing share of intermittent energy sources causes on the power grid. The non-plannability of intermittent power production requires solutions to maintain a stable and reliable power grid. Further commercialization of BESSes is also seen as use increases for electric vehicles and other mobile use.

    A distribution grid owner, referred to as the Company, has a power subscription for power that is fed from the regional grid, where additional power peak fees are added when exceeding the subscription limit. This study investigates whether a Lithium-ion BESS can be financially beneficial for the Company by examining two power grid services. The first one is power peak shaving, and the second one is energy arbitrage. Energy arbitrage signifies that the BESS is charged during low electricity prices and discharged during high prices, thus generating profit. This is accomplished by simulating a Lithium-ion BESS in MATLAB (2019) where the studied services are combined.

    The results show that a Lithium-ion BESS can be used for the purpose of peak shaving and energy arbitrage, although an investment is not profitable for the Company with the current market situation. The sensitivity analysis does however indicate profitability if the current power peak fees and spot prices remain unchanged while the BESS investment cost is reduced by 50%. This decrease in BESS cost is predicted possible within the next decade as BESS demand is expected to increase. The study implies that the main factor effecting the solution to be profitable is the high investment cost.

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  • 5.
    Achour, Nemer
    Sveriges lantbruksuniversitet.
    Evaluating energy efficiency and emissions of charred biomass used as a fuel for household cooking in rural Kenya2015Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In sub-Saharan Africa a large share of the energy use utilize biomass as a fuel. In some

    countries more than 90 percent of the energy use is biomass. This energy is primarily used for

    cooking, heating and drying. Cooking food on an open fire or using a traditional stove will

    combust the firewood inefficiently and leads to pollution in the form of particulate matter,

    carbon monoxide and other hazardous pollutants. Indoor pollution has serious health effects

    and especially women and children are affected by this since they spend more time in the

    kitchens compared to men.

    More efficient combustion would lead to less harmful pollution to women and children in

    these rural areas. There are different kinds of stoves on the market and one of them is the

    gasifier stove which allows the biomass to go through pyrolysis in a separate step before

    complete combustion. If the charred biomass is harvested before complete combustion it can

    be saved for later use. This stove will result in cleaner and more energy efficient combustion

    compared to the traditional 3-stone-fire.

    The aim of this study has been to evaluate the charred biomass harvested from this gasifier

    stove in terms of energy use efficiency, emissions and cooking time. The charred biomass was

    compared to conventional charcoal bought at the local market. The charred biomass

    investigated is charred Grevillea prunings from the

    Grevillea Robusta tree, charred coconut

    husks (

    Cocos nucifera) and charred maize cobs (Zea mays). They were tested by cooking a

    meal consisting of two dishes at five different households for different kinds of charred

    biomass and conventional charcoal as a reference.

    Using charred Grevillea prunings gives an energy saving up to 31 percent while charred

    coconut husks gives up to 11 percent energy saved compared to the 3-stone-fire. Charred

    maize cobs was only up to 2 percent more energy efficient than conventional charcoal due to

    its low energy density and fast burning rate. In most cases there was no significant difference

    between the emissions of the different charred fuel types. Only charred maize cobs resulted in

    significantly higher emissions than the other fuels. Household B deviated from the others

    households and had higher emissions. In conclusion the different types of charred biomass are

    good fuels for cooking. Charred maize cobs are less valuable since they require a higher rate

    of refilling of fuel during cooking and do not result in better energy use efficiency compared

    to conventional charcoal.

    There were no significant differences between the different types of charred biomass and

    conventional charcoal in emissions except for a few cases where charred maize cobs had a

    slightly higher level of emission compared to the others. CO

    2- levels were so low that there

    was no risk of harmful concentrations in any way. PM

    2.5-emissions levels were safe, but the

    CO-emissions levels for charred maize cobs were close to levels were symptoms might show.

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  • 6.
    Adolfsson, Joakim
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Electronics.
    Characterization of combinatorial Cu2ZnSnS4 thin films2018Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The kesterite Cu2ZnSnS4 (CZTS) is considered as a possible absorber layer in future photovoltaic (PV) applications. The abundance of its constituent elements along with the material being non-toxic and having a direct band gap of around 1.5 eV make it an attractive material for solar cell applications. So far, cells with an efficiency of 12.6 % have been achieved. The limiting factor is the finished cells' open circuit voltage (VOC) deficit which has been attributed to structural defects in the material. Problems with sustaining a sulfur-enriched atmosphere during the annealing step of material production have been observed, and are thought to be partially responsible for the high density of structural defects. Elemental sulfur is commonly used for inducing a sulfur-enriched atmosphere in the anneal. In this study, four combinatorial and polycrystalline CZTS thin films were prepared and annealed in different conditions with regards to time, sulfur source and amount. The samples were characterized using energy dispersive-, Raman- and photoluminescence spectroscopy. The effect of the anneal on the different composition regions were analyzed and secondary phases were identified. Introducing CuS as the sulfur source during the anneal reduced the decomposition of the CZTS phase, and lowered the density of the defect complex [ZnCu + CuZn], while enlarging the single phase region. Strictly and highly Sn-rich compositions of CZTS was observed to yield both high cation order and photoluminescence intensity, and a link between the two parameters was observed.

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  • 7.
    Agerhäll, Isabella
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Electricity.
    Flexibilitet i elsystemet: En undersökning om hur flexibilitet lokalt kan samverka med de nationella stödtjänstmarknaderna2022Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The Swedish power system is facing a lot of change in the near future. A system which is built around nuclear- and hydropower now contains more and more intermittent power sources such as wind and solar. In addition, Sweden is entering a second electrification era, where the electricity use is predicted to increase substantially. This means the need for flexibility in the power system is bigger than ever and is going to increase.

    The power system needs to be in balance at every instance. The same amount of energy that is produced also needs to be consumed. This balance, or imbalance, affects the frequency in the system and there are balancing markets in place to handle disturbances in the frequency.Flexible solutions outside these balancing markets can also be valuable since they can lower costs for power use and prevent unnecessary investments in the power grids.

    This thesis was written in cooperation with the municipal energy company Gävle Energi. The cases it is built on are both cases in and around Gävle. The study is based on two cases: One case where a local hauling company is interested in a combination of solar power, electric charging for vehicles, and a battery storage. The hauling company plans to electrify parts of their fleet and will by doing so increase their power use. The second case regards the building of a gasturbine for electricity production in Gävle Energi’s grid.

    Both cases examine how the balancing markets can be used to motivate investments in flexible solutions. The hauling company can lower their power peaks by using a battery storage and the battery storage can also be used to sell capacity on the balancing market FCR-D. Through planning when heavy duty charging and regular vehicle charging is done, unnecessary power peaks can be avoided. The study shows that a battery storage can in fact be profitable and bring benefits to both the hauling company and the national energy system.

    The second case, the gas turbine, is based on income from both the spot market and the balancing market mFRR which is then compared to the price for gas. The income from mFRR was varied between 140-250% of the prices from 2021 and the gas price was varied from 800-2100 SEK. The results show that the prices for mFRR need to increase a lot for the turbine to be profitable and the gas turbine could perhaps be more beneficial if combined with other solutions. The case has a lot of insecurities as the turbine runs very few hours per year (only 10 hours would have been profitable in 2021). It becomes vital that the bidding is won these hours, which is hard to predict.

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    Flexibilitet_i_elsystemet
  • 8.
    Ahlberg, Johan
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    Georges, Elza
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    Norlén, Mikael
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    The potential of hemp buildings in different climates: A comparison between a common passive house and the hempcrete building system2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The aim of this bachelor thesis was to study the potential of hemp buildings in different climates. The report examines and models two different energy efficient building concepts – the more common passive house and the environmental friendly hempcrete building system. These two buildings thermal performances were then simulated and compared in different climates followed by a brief discussion about their economic and environmental impact.

    The simulation was performed with the energy calculating program VIP-energy v 2.1.1 with the two models located in Kiruna, Sundsvall, Malmo, Berlin and Rome to represent the different climates. Simulations for different wall sizes and a sensitivity analysis of some significant parameters were also made.

    The hempcrete building system showed to have a thermal performance similar to that of passive houses in more southern climates. In the north of Sweden however the hempcrete building required up to 20 % more energy than the passive house to maintain comfortable indoor temperatures. This deficit could be compensated for with hemp fibre insulation to augment the building envelope and U-value. Furthermore the hygrothermal material properties that were not included in the simulation can be expected to have a significant positive impact on hemp buildings relative thermal performance.

    With a passive house thermal performance, a healthy indoor environment and an economically viable and environmental friendly production process hemp building demonstrated great potential in all the fields studied.

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    The potential of hemp buildings in different climates
  • 9. Ahlm, Niklas
    Laststyrning av eluppvärmning och varmvattenberedning: En studie av potentialen för hushåll att bidra till en sänkt abonnerad effekt mot överliggande elnät2021Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This study has explored the potential for lowering the subscripted power of 25 MW for one of the connection points between the local power grid and its overhead power grid for a local grid owner. The potential for doing so through hard, direct load control of electrical domestic heating and domestic water heating for detached houses with a fuse size of 16-25 A is evaluated for 12 different scenarios. The scenarios are found by combining a customer participation of 25, 50, 75 and 100 percent with a maximum allowed duration for load control of two, three and four hours respectively. A function describing the need for electrical power for domestic heating as dependent of the outdoor temperature is developed and combined with a model that is used for simulating hot water usage and a model that describes the power demand of a domestic water heater. Furthermore, a control function is incorporated to ensure that households are not subjected to load control for a longer period than allowed and that all households bear the same burden in this respect. 

    The results show that a power of 1,0-4,1 MWh/h can be redistributed, but that the potential is heavily limited by the returning load that occurs. Due to the long duration of the critical peaks that are being redistributed, up to 5-10 hours, returning load occurs even though load control has not yet been finalized. The returning load leads to a bigger amount of power having to be redistributed and therefore limits the potential for the new subscripted power that can be achieved. Furthermore, the maximum aggregated power for the investigated year amounts to 25,9 MW. Still, a new subscripted power of 21,8–24,9 MW is theoretically deemed to be achievable. The most likely outcome however is thought to be a lowering of the subscripted power to at least 23,4–24,4 MW, having taken the composition of type of heating systems as well as the most likely customer participation into account. 

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    Laststyrning av eluppvärmning och varmvattenberedning: En studie av potentialen för hushåll att bidra till en sänkt abonnerad effekt mot överliggande elnät
  • 10.
    Ahlvin, Martin
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Arriaga, Yasmine
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Bauman, Elise
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Berglund, Hanna
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Magnusson, Clara
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Wiklund, Sofia
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Energiomställning Gotland: Alternativ för att nå ett förnybart energisystem2018Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Sammanfattning

    Syftet med denna studie är att i åtta scenarier konkretisera hur Gotland skulle kunna ställa om till en förnybar energiförsörjning. Detta ska visa vägen för hela Sveriges omställning till förnybar energi 2040. Studien ska tjäna som en första orientering av vad fortsatt forskning kan inriktas på. Metoden var främst litteraturstudie samt modellering och beräkningar utifrån representativa exempel. Bedöm- ning av alternativ gjordes utifrån de övergripande kriterierna hållbarhet, resurseffektivitet och realis- tisk potential. Som begränsning utgick studien från åtta scenarion med olika förutsättningar och olika fokus. Tidsramen var fram till 2030.

    Scenario 1 - Transport: I scenario 1 var fokus att göra transportsektorn förnybar. Biogas och el från vind- kraft ansågs vara de energikällor som bäst ersätter de fossila bränslena. Import av biodiesel bedömdes även nödvändig, framför allt till tung transport. Utmaningen ligger främst i den omfattande omställ- ningen som krävs av fordonsflottan.

    Scenario 2 - Industri: I scenario 2 fokuserades endast på industrins omställning till förnybar energi. Framför allt cementproducenten Cementa använder en stor andel av Gotlands energi. Alternativet med störst potential, och som bör prioriteras för fortsatta studier, ansågs vara att att elektrifiera Ce- menta.

    Scenario 3 - Bioenergi: I scenario 3 skulle bioenergi användas för att ersätta fossila bränslen, samtidigt som Gotland var självförsörjande på livsmedel. Industrin bortsågs ifrån. De två intressena visade sig vara förenliga.

    Scenario 4, 5 och 6 - Reglering: Scenario 4, 5 och 6 fokuserar alla på olika typer av energilagring och reglering. Detta är nödvändigt i ett energisystem som till stor del bygger på vindkraft och solenergi. Batteriparker, tryckluft, pumpkraft och vätgas studerades som möjliga lagringsmetoder. Främst bat- terier i kombination med vätgas ansågs ha potential på Gotland. Fortsatt breda studier krävs dock.

    Scenario 7 - Ingen kabel: Idag finns en kabel mellan Gotland och fastlandet för import och export av elektricitet. I scenario 7 kan den kabeln inte användas. Stor utbyggnad av vindkraften krävs då, spe- ciellt havsbaserad. För att lättare reglera energin föreslogs att Gotland delas in i mindre system.

    Scenario 8 - Energiplan 2020: Region Gotland har satt upp mål för energisystemet år 2020 i Energiplan 2020. I scenario 8 studerades hur energisystemet skulle kunna se ut om målen uppfylldes. Stora för- ändringar från dagens energisystem skulle krävas.

    Slutsatsen av studien var att fortsatta studier främst ska riktas mot möjliga lagringstekniker, indu- strins energiförsörjning samt samhällets inställning till en energiomställning. Lagringstekniker är en förutsättning för den storskaliga utbyggnad av vindkraft som är nödvändig och som finns potential för. Grundläggande för att nå ett förnybart energisystem är hela samhällets delaktighet. Att kartlägga allmänhetens drivkrafter och motsättningar är därför viktigt.

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  • 11.
    Al Hamed, Hassan
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    ONSHORE WIND FARM REPOWERING ALTERNATIVE SCENARIOS AND COST ASSESSMENT2021Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Many reasons to consider extending the useful time of ageing wind farms. Like to take advantage of it being located in a good wind source, besides existing infrastructure, etc. Repowering can be an appropriate option for the ageing wind farm that suffering less yield energy and increment of cost of operation and maintenance. 

    The thesis discusses the repowering potential of old wind farms. The case study is implemented on a selected wind farm in Denmark. Different repowering scenarios were considered with the technical-economic assessment for each scenario to determine which scenario is viable. The sensitivity analysis was done taking into consideration selected parameters to find out the effect of each parameter on the profitability and productivity of the repowered wind farm. More details will be explored in the following chapters. 

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  • 12.
    Aldahan, Filip
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Svensson Grape, Joakim
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Beräkning av kostnader för lågaktiv kärnavfallshantering2016Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The surtax in Sweden, which exclusively applies for nuclear power plants, in conjunction with low electricity prices, has forced Swedish nuclear power plants to minimize their expenses.

    At Oskarshamn power plant, estimation of cost, associated with low-level nuclear waste management has been conducted several years ago, but with lacking knowledge about how the calculations were performed. Therefore, the purpose of this project was to establish an independent cost estimation for compactible and non-compactible, low level and medium level nuclear waste. Cost estimates for free released low-level nuclear waste was also performed.

    By analyzing average economic figures from year 2014-2015 and visits on-site, an excel-based calculation template was accomplished. During the on-site studies, several visits to the low-level nuclear waste management facilities at Oskarshamn power plant were made, in order to get an overview of how the handling process works.

    By following the staff around, it was possible to estimate some of the time durations for the different parts in the handling process for compactible lowlevel nuclear waste, that were used in the calculations.

    The price for compactible low-level nuclear waste was calculated to 6,72 - 6,97 kr/kg, depending on the activity level. The non-compactible low-level nuclear waste price was found to vary between 4 – 48 kr/kg.

    The large fluctuations are due to different activity levels and associated additional costs in handling, measuring, final deposition etc.

    For both compactible and non-compactible nuclear waste, the storage cost is a factor that dominates the total cost and that could be minimized. Based on the analysis presented in this work, the cost can be decreased by reducing the storage time and/or store the nuclear waste in a more space efficient way.

    The cost estimate for free released material is low (5,94 – 8,74 kr/kg), which concludes that Oskarshamn power plant may profit from free releasing as much material as possible, due to the fact that it is highly profitable to recycle metals.

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  • 13.
    Aldén, Liselotte
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences. Nätverket för vindbruk.
    Ridbäck, Ulrika
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    New and Ongoing Wind Power Research in Sweden 2019: A compilation of Swedish research programs and new scientific publications on wind energy2020Report (Other academic)
    Abstract [en]

    The Node for education and competence in the National network for wind utilization annually publishes a summary of new and ongoing wind power research in Sweden. The aim of this summary is to provide an easily accessible overview of what is happening annually in wind power research for interested parties. This compilation is divided into two sections. The first is a presentation of the research centres and research programmes active in wind power research in Sweden. Then a topic-based list of the wind power research published in 2019 follows where at least one of the authors is active at a Swedish university. Here one also can find doctoral and licentiate theses as well as theses at bachelor and master levels that have been published during the year.

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  • 14.
    Aldén, Liselotte
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences. Nätverket för vindbruk.
    Ridbäck, Ulrika
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences. Nätverket för vindbruk.
    Ny och pågående vindkraftsforskning i Sverige 2019: En sammanställning av svenska forskningsprogram och publikationer inom vindkraftsområdet2020Report (Other academic)
    Abstract [en]

    The Node for education and competence in the National network for wind utilization annually publishes a summary of new and ongoing wind power research in Sweden. The aim of this summary is to provide an easily accessible overview of what is happening annually in wind power research for interested parties. This compilation is divided into two sections. The first is a presentation of the research centres and research programmes active in wind power research in Sweden. Then a topic-based list of the wind power research published in 2019 follows where at least one of the authors is active at a Swedish university. Here one also can find doctoral and licentiate theses as well as theses at bachelor and master levels that have been published during the year.

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  • 15.
    Alenius, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Analys och vidareutveckling av marknadsstyrd effekttariff inom eldistribution: En fallstudie av Sandviken Energi Elnät AB:s effekttariff2017Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This master thesis evaluates the incentives of a newly implemented market controlled network tariff by analyzing consumption data and constructing a time-differentiated debiting model. The tariff was implemented by Sandviken Energi Elnät AB and the thesis evaluates its customers consumption data compared to data provided by Sundsvall Elnät AB. The differences in data is evaluated by statistical tests of Students t-test, Bayesian t-test and χ2-test with the result that no statistically significant change in user pattern can be found and thus an elucidation of the incentives must be made in the form of a hourly time-differentiated debating model. The thesis also evaluates the cost incentives of the model compared to spot prices where it is shown that the tariff model can benefit much from the spot prices hourly incentives in its hourly time-differentiated model. Five time-differentiated models were constructed and presented where three uses a color coding scheme. The conclusion is that a color coded time-differentiated tariff should give the costumers clear and cost-effective incentives.

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    Marknadsstyrd effekttariff inom eldistribution
  • 16. Alev, Ullar
    et al.
    Eskola, Lari
    Arumägi, Endrik
    Uppsala University, Disciplinary Domain of Humanities and Social Sciences, Faculty of Arts, Department of Art History.
    Jokisalo, Juha
    Donarelli, Anna
    Uppsala University, Disciplinary Domain of Humanities and Social Sciences, Faculty of Arts, Department of Art History.
    Siren, Kai
    Broström, Tor
    Uppsala University, Disciplinary Domain of Humanities and Social Sciences, Faculty of Arts, Department of Art History.
    Kalamees, Tango
    Renovation alternatives to improve energy performance of historic rural houses in the Baltic Sea region2014In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 77, p. 58-66Article in journal (Refereed)
    Abstract [en]

    This paper analyses renovation alternatives to improve energy performance of historic rural houses in three countries (Estonia, Finland, Sweden) in the Baltic Sea region (cold climate). The study was conducted by a combination of field measurements and simulations. Indoor climate, typical houses and structures as well as the current condition and need for renovation were determined by field measurements. Based on field measurements, indoor climate and energy simulation models were validated and used to calculate energy use for different renovation measures. Energy renovation packages were calculated for different scenarios (minimal influence on the appearance of the house, improvement of thermal comfort, improvement of building service systems) for different energy saving levels. The analysis showed that the improvement of building service systems and the energy source holds the largest energy saving potential. The building envelope of old rural houses needs improvement also due to high thermal transmittance and air leakage. The insulation of the external wall has the largest single energy saving potential of the building's envelope. The results show how energy savings depend on energy saving targets, typology of the building, thermal transmittance of original structures, and building service systems. (C) 2014 Elsevier B.V. All rights reserved.

  • 17. Alexandrou, E.
    et al.
    Katsaros, M.
    Aravantinos, D.
    Axarli, K.
    Chatzidimitriou, A.
    Gotoudis, A.
    Theodosiou, Th.
    Tsikaloudaki, K.
    Technical guidelines for energy efficiency interventions in buildings constructed before 1955 in Greece2018In: Conference Report: The 3rd International Conference on Energy Efficiency in Historic Buildings / [ed] Tor Broström, Lisa Nilsen and Susanna Carlsten, Uppsala University, 2018, p. 294-301Conference paper (Refereed)
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    fulltext
  • 18. Alhoush, George
    et al.
    Edvardsson, Emil
    Peak shaving optimisation in school kitchens: A machine learning approach2022Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    With the increasing electrification of todays society the electrical grid is experiencing increasing pressure from demand. One factor that affects the stability of the grid are the time intervals at which power demand is at its highest which is referred to as peak demand. This project was conducted in order to reduce the peak demand through a process called peak shaving in order to relieve some of this pressure through the use of batteries and renewable energy. By doing so, the user of such systems could reduce the installation cost of their electrical infrastructure as well as the electrical billing. Peak shaving in this project was implemented using machine learning algorithms that predicted the daily power consumption in school kitchens with help of their food menus, which were then fed to an algorithm to steer a battery according to the results. All of these project findings are compared to another system installed by a company to decide whether the algorithm has the right accuracy and performance. The results of the simulations were promising as the algorithm was able to detect the vast majority of the peaks and perform peak shaving intelligently. Based on the graphs and values presented in this report, it can be concluded that the algorithm is ready to be implemented in the real world with the potential to contribute to a long-term sustainable electrical grid while saving money for the user. 

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    fulltext
  • 19.
    Ali, Roni
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Electricity.
    Helelektriska tunga lastbilar: En studie om påverkan på elnätet2023Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Sweden has ambitious climate goals, such as the overarching goal, the 2045 goal. The goal is for Sweden to have zero net emissions of greenhouse gases by 2045 at the latest. In order to achieve the overall climate goal and the interim targets, electrification of society is an important component.

    The industrial sector and the transport sector each account for about a third of Sweden’s emissions, where the conversion to electricity is an important solution. The electrification of passenger cars and buses has meant that emissions from domestic transport have decreased every year, and in order to achieve the interim target of 70 percent lower emissions of greenhouse gases in 2030 compared to 2010, the electrification of heavy duty trucks is one of the key components.

    However, there are long-term challenges with the power grid and already today grid owners have capacity challenges. Regional grid owners cannot increase their power subscription, while local grid owners cannot grant new connections.

    Regarding the electrification of long-haul transportation, there are challenges in terms of charging infrastructure. Truck drivers operate on a strict schedule, and minimizing down time is crucial to keep costs down. By law, truck drivers must take a 45-minute break after 4.5 hours of driving time, which means that during this break it is desirable to recharge the vehicle before departure. This means that high power demands are placed on the charging infrastructure that exists to be able to transmit the desired energy.

     

    A new standard, the Megawatt Charging System (MCS), which meets the high power requirements has been developed and is included in pilot projects. The maximum power that the charging standard can deliver is 3.75 MW.

    The results of the thesis show that these high-power chargers place high demands on thepower grid. When connecting a charging station with MCS charging points to the grid, it may require local upgrading of lines and transformers, but also upgrading in otherparts of the network. Examples of such upgrades are reactive power compensation to be able to support the network locally at peak loads to obtain voltage levels within stable voltage ranges, but also upgrades of lines and transformers to be able to deliver the desired power.

    Integration of a battery storage in connection with a charging station relieves the powergrid and its components. However, it is important to highlight that since the battery needs to be recharged, this means that a more even power requirement is needed. However, the  maximum load on both transformers and lines is reduced, which can be a desirable effect when a charging station of the same nature is put into operation.

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  • 20.
    Al-Sallami, Omer
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    CABLES DECOMMISSIONING IN OFFSHORE WIND FARMS: ENVIRONMENTAL AND ECONOMICAL PERSPECTIVE2021Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Addressing the decommissioning issues is vital to ensure a sustainable and effective process of such an essential part of the project life cycle. While there is a set of good practices and regulations that govern most of the decommissioning activities, the cable decommissioning issue is still in a big debate and often left abandoned at the seabed due to environmental concerns, as justified by most developers. This paper is aiming to understand the environmental and economic consequences of cable decommissioning.

    The available research papers and reports that are dealing with cable decommissioning issues have been reviewed. The cables are often decommissioned using similar methods to installation. However, there are no regulatory obligations to removing the cables in most countries. Cable installation will be associated with environmental impacts, but they are considered to be negligible. Additionally, Recycling cables’ copper is beneficial in both aspects environmentally and economically as copper prices are on the rise.

    A comparison between the ESs and decommissioning programs in a number of OWFSs have been conducted to understand the justification used for abandoning the cables. Most of the decommissioning reports have considered cable decommissioning to cause “considerable damage to seabed ecology”. However, that contradicts what was found in the ESs, where the impact level was considered negligible and anticipated to be similar to installation. It was unclear whether the abandonment of cables was driven by environmental considerations or not.

    A case study has been selected to compare cable and monopile decommissioning costs and the contribution of each component to the total decommissioning cost, including possible revenue generated from recycling. It was found that the cost-benefit of cable decommissioning is incomparable to monopile decommissioning as the latter is very costly, and the possible residual value is insignificant when compared to cables. Moreover, it is possible that the total cable decommissioning cost to be largely offset by the revenue generated from copper resell. Additionally, the cable decommissioning total cost can be almost paid by recycling cables if copper prices increase in the near future.

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    Offshore wind energy
  • 21.
    Alsterlund, Hanna
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Industrial Engineering & Management.
    Effektiva återkopplingsverktyg för elanvändning: En studie som syftar till att identifiera utvecklingsmöjligheter för att uppnå ett mer hållbart energisystem år 20302015Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Feedback tools support electricity users within the Swedish residential sector to increase their knowledge of electricity and the electricity market as well as to become more aware of their electricity consumption, which in turn encourages a reduction and an increased flexibility of electricity use. The primary aim of this study is to identify and analyse how existing feedback tools can be improved, to ensure that they contribute efficiently to the achievement of the EU objectives congruent with a more sustainable energy system in 2030, emphasizing: greenhouse gas reduction, increased energy efficiency and an increased share of renewable energy. In order to reach the primary aim of this study, existing feedback tools have been identified and mapped and interviews with feedback tools providers have been conducted. The study is limited to three research areas: the practical functions of feedback tools, available technology and the use of feedback tools.

    The use of more efficient feedback tools will provide an increased success rate for energy management, which includes both behavioural changes and energy efficiency. According to the results from the interviews conducted for this study, an increased use and user frequency is important to utilise the energy management potential. Efficient feedback tools can be achieved by developing existing tool functions. The desired development aims to reduce the effort required of the user, promote immediate and continuous feedback and to increase usability. However, the study shows that in order to achieve maximum effect, adaptions to specific needs of the users have to be made. An increased efficiency may also be achieved with additional features to allow more flexible consumption and encourage further energy efficiency measures.

    The technical aspect is important in order to implement more efficient feedback tools. Existing techniques for data collection should be developed in order to reduce the effort required of the user, enhance the quality and resolution of the data and finally prevent technology limitations, hence enabling feedback tools to be used by all users.

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  • 22.
    Ammon, Anton
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
    Comparing the benefits of energy saving measures with seasonal solar thermal heat storage2014Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis compares the effects of energy saving measures with Active Solar Energy

    Storage (ASES) on a property owned by Stena Fastigheter. The building is located in

    Lövgärdet in Gothenburg and was a part of the Million Homes Program. It was built in 1967, has 9 floors, a heated basement and is heated by district heating. The thermal envelope of the building consists of the walls, doors, windows, roof/attic and the basement.

     

    ASES is a system consisting of solar panels on the roof of a building connected to the heating system. The solar energy that cannot be used immediately is stored in a ground storage unit for when it is needed. ASES can also be supplemented by geothermal heating by drilling boreholes into the ground and, via a Ground Source Heat Pump (GSHP), using the heat in the underlying rock.

     

    The ASES and GSHP system combined were compared to energy saving measure on the thermal envelope in terms of reducing the need for purchased energy and increasing profitability. The energy saving measures were: changing the 2-pane windows to 3-pane windows (either by adding a window pane or changing to a 3-pane window), insulating the façade, insulating the attic, insulating and draining the basement, changing doors, replacing the heat exchanger with a more efficient one, and improving ventilation system. The new system, called FTX, reuses the heat from the exhaust air to save energy.

     

    The results of the thesis show that it is difficult to make energy saving measures profitable. Of the measures evaluated, draining and insulating the basement is extremely cost effective, with a payback time of less than two years. Other profitable measures are insulating the walls (renovation costs of the wall excluded) and insulating the attic, but with a much longer payback time. The ASES and GSHP system are profitable and greatly reduced the need for purchased energy, but require a long payback time. The sum of all energy saving measures does not reduce the need for purchased energy as much, or as cheaply, as ASES, which reduced the energy usage by 62 %.

     

    Due to limited solar panel area ASES cannot supply enough heat to cover the heat demand of the studied building. ASES is therefore believed to be better suited for the buildings that surround the evaluated building. The surrounding buildings have fewer storeys, larger roof area where solar panels can be mounted, and open areas better suited for the ground storage. The potential to implement the ASES system for buildings like these from the Million Homes Program should be evaluated further.

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  • 23. Andersson, Agnes
    Battery energy storage systems in Sweden: A national market analysis and a case study of Behrn sport arena2018Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The renewable energy sources increase the volatility on theelectricity market. To manage the quick variations battery energystorage systems (BESS), together with other storing solutions, willbe required in the future. Depending on which level in the grid thebattery is placed, it can serve different purposes. In this report amarket analysis is conducted, which examine the performance ofbattery storages installed in Sweden. Further on, a simulation, withPV-panels and a battery, was performed at Behrn Arena in Örebro.

    From the market analysis it was shown that the majority of therespondents had used, or will use, their battery for peak shaving.This function is particularly meaningful for customers with a powertariff, which is the case for Behrn Arena. The simulated systemdecreased their yearly cost due to the power tariff with 70 000 SEKand the total electricity bill decreased with 155 000 SEK.

    For the batteries to be more profitable in the future, the batteryprice needs to decrease or the number of revenue streams need toincrease. One revenue with great potential is frequency regulation,which has proven its efficiency in other countries.

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  • 24. Andersson, Elinda
    Vidareutveckling av metod för bedömning av miljöpåverkan i samhällsekonomiska analyser vid investeringar i det svenska elstamnätet2016Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Svenska kraftnät, which is the authority responsible for the Swedish national grid, performs cost-benefit analysis (CBA) to assess which of different investment projects that are of greatest benefit to society. The environmental impacts are also estimated during this analysis. In this paper, a tool for estimating the environmental impacts during the lifetime of a grid component has been developed with the purpose of enabling a more complete environmental evaluation. A life cycle assessment was performed to develop the tool. The impact categories that have been studied are climate change (kg CO2-eq), freshwater eutrophication (kg P-eq), particulate matter formation (kg PM10-eq) and terrestrial acidification (kg SO2-eq). To be able to compare the environmental effects with other costs and benefits in the CBA a monetary valuation of the impact categories has been established. The result of this paper indicates that the AC-overhead line is the technology that contributes with the lowest environmental impact during the life cycle. This result, however, is obtained when analyzing different technical alternatives with the same preconditions, which rarely is the case in real projects. The result can therefore differ between different investment projects. The tool enables an assessment of the environmental impacts of different investment projects in the Swedish national grid, and is therefore an important part of the cost-benefit analysis to determine which alternative is best suited. 

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    Andersson_Elinda
  • 25.
    Andersson, Emil
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Mathematics.
    Småskalig elproduktion i urban miljö: Fallstudie av elproducerande system på ett handelscentrum2013Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis investigates if a system for small scale electricity production located in anurban environment can be profitable. The work has been divided up into two parts,one extensive literature study and one case study. The purpose of the literature studywas to investigate the area, resulting in a choice of which technology to be studied indepth in a case study.In the case study a system containing small scale wind turbines and photovoltaicsmounted on Gränby Centrums roof was examined. From data containing wind power,wind direction and total irradiation, possible production from a system weresimulated. Three products of each technology were examined in the simulations.From the simulated production an economic analysis was carried out, this toinvestigate if a system is profitable. The two alternatives that showed the besteconomic result formed the optimal system.The economic analysis showed that none of the investigated alternatives whereprofitable, this because the capital costs exceeded the revenues. The revenues fromthe wind turbines were low because of the poor wind conditions in an urbanenvironment and the revenues from the photovolatics were low because of the lowelectricity price.

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    fulltext
  • 26.
    Andersson, Erik
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Wengberg, Fredrik
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Utvärdering av konsekvenserna för nätanslutning av vindkraftparker i Sverige vid införandet av nätkoden Requirements for Generators2015Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Grid codes are becoming more demanding on power generating units due to the factthat the complexity of the power grid is increasing. The penetration of wind powerhas grown over the last years and it is clear that wind farms need to be addressedwith the same type of grid codes as conventional generation units. There is howeveran undeniable difference between the technology in conventional synchronousgeneration units, and the asynchronous generation units in wind farms.

    This thesis has reviewed the current grid code in Sweden and compared it to the newcode proposed by ENTSO-E, “the Requirements for Generators”, in the aspect ofwind farms with an installed power of 30 MW or more. The comparison has beencomplemented by an analysis of how wind farms of two different technologies(Doubly fed induction generators and full power converters) can meet therequirements and technical proposals have been given on how to be able to meetcompliance with the new grid codes.

    The Requirements for Generators contains many non-exhaustive and optionalrequirements, because of this it has been difficult to, at this stage, exactly point outthe technical impact on the grid connection of future wind farms in Sweden. For manyof the requirements in the Requirements for Generators there is no equivalent in theSwedish Grid Code (SvK FS2005:2) but counterparts can thus be found in existingpractices and therefor does not imply any major differences for the industry.

    The requirements of frequency regulation, synthetic inertia and reactive powercapability are the main components of the RfG which will require additional softwareand hardware installations for future wind farms in Sweden.

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  • 27.
    Andersson, Jonas
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    Bernström, Vendela
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    Törnqvist, Joacim
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    Hosting Capacity of a Low-Voltage Grid: Development of a Simplified Model to be used in future Solar Roadmaps2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The purpose of this bachelor thesis is to assess whether it is possible to create a simplified model that estimates the hosting capacity of a low-voltage grid. The Simplified model is compared with a more elaborate model created by the Built Environment Energy Systems Group (BEESG) at Uppsala University. The Simplified model takes three easily obtainable variables into account. The model created by BEESG allows us to observe both the amount of photovoltaic (PV) power that is installed as well as the voltages in each bus in a grid. The hosting capacity is found by gradually increasing the amount of PV power installed in a low-voltage grid until overvoltage is reached. Simulations with BEESG’s model are done for a week in July when the PV generation has its peak and the load is generally low. The Simplified model is created using linear regression with the calculated values from the BEESG’s model as a reference. The report shows that the Simplified model will give an estimation of the low-voltage grid’s hosting capacity that is comparable to the value calculated with BEESG’s model. The results show that it is rarely the low-voltage grid that restricts the installation of PV facilities and that a high self-consumption is advantageous regarding to the grids hosting capacity.

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  • 28.
    Andersson, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Kärnkraft - Vad är det?2019Other (Other (popular science, discussion, etc.))
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  • 29.
    Andersson, Viktoria
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    Elbilar på Lidingö: Påverkan på det regionala elnätet2018Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis aims towards increasing the understanding of how the growing number of electric cars is going to affect the regional power grid of Stockholm. The results are meant to aid in long term planning of maintenance and development of the regional power grid. Three possible scenarios are presented for the development of electric cars on Lidingo until the year 2040. The number of electric cars, maximum load and load profiles are calculated and analyzed for each scenario. Possible measures of value for the DSO Ellevio are then presented.

    By the year 2040 it is likely that at least one fourth of cars are electric. The maximum power loads from the charging of electric cars will coincide with already existing power peaks during early evening. Loads from charging of electric car will cause a significant contribution to the loads of the regional power grid. If international, national and local climate goals are to be fulfilled the loads would be even larger, though that scenario is deemed unlikely. It is concluded that extensive measures in the regional power grid of Lidingo are needed in order to handle the new maximum loads. It is suggested that Ellevio should start planning for upgrading components, install energy storages and work for load shifting in order to handle the higher loads.

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    Andersson_Elbilar_pa_Lidingo
  • 30. Angwald, Filip
    Power mapping and aggregation as a service: A techno-economic view on Li-ion batteries for peak shaving and frequency regulation2020Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The world's energy supply today mainly consists of fossil fuels and nuclear power. Moving away from the use of these energy resources to renewable energy sources is considered a prerequisite for a sustainable future. In order to implement this change, it is necessary for renewable energy sources to be environmentally, technically and economically sustainable. A major challenge encountered in terms of technological sustainability is the intermittent nature of renewable energy sources. As the share of renewable electricity increases in the system, the electricity grid is facing new challenges such as increased instability of the frequency and capacity shortages. In order to meet these new challenges an increased flexibility from electricity users is proposed as a solution. Flexibility can be achieved either by controlling the use of electricity or utilizing energy storages. If different electric loads are to be controlled in a property, data regarding the power use of the loads must first be collected with a high time resolution in order to be able to properly analyze the data. Measures to shift or reduce the power peaks in a property can then be suggested and implemented. A battery storage can help reduce power peaks or shift loads in time and if done on a large scale that would reduce the strain on the entire Swedish grid. One of the ancillary services that the battery could offer is frequency regulation. Using energy storages for such an application could also provide a secondary revenue stream, aside from the revenue stream from peak shaving, and increase the profitability of the storage. Sweden has seen a dramatic increase in electric vehicles over the last decade and charging of the vehicles has become an issue for many property owners as it often creates power peaks. The data collection regarding power use in properties performed in during this thesis showed that valuable data can be collected with the method and material used. With a battery price of 3000 SEK/kWh the payback time for a battery system can be reduced from 17,9 to 7,8 years if it is used for frequency regulation during the night. If power-intensive loads such as electric vehicle charging are added to the model the payback period decreases to 6,1 years. With these results in mind, it can be concluded that the profitability of a battery storage can increase to the extent that the investment is of economic viability. In addition, the investment helps to improve the stability of the Swedish grid. The results are found to be relatively consistent with those of other similar studies.

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  • 31.
    Anttila, Sara
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Electricity.
    Döhler, Jéssica
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Electricity.
    Oliveira, Janaína Goncalves de
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Electricity. Univ Fed Juiz de Fora, Dept Elect Energy, BR-36036330 Juiz De Fora, Brazil..
    Boström, Cecilia
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Electricity.
    Grid Forming inverters: A review of the state of the art of key elements for microgrid operation2022In: Energies, E-ISSN 1996-1073, Vol. 15, no 15, article id 5517Article, review/survey (Refereed)
    Abstract [en]

    In the past decade, inverter-integrated energy sources have experienced rapid growth, which leads to operating challenges associated with reduced system inertia and intermittent power generation, which can cause instability and performance issues of the power system. Improved control schemes for inverters are necessary to ensure the stability and resilience of the power system. Grid-forming inverters dampen frequency fluctuations in the power system, while grid-following inverters can aggravate frequency problems with increased penetration. This paper aims at reviewing the role of grid-forming inverters in the power system, including their topology, control strategies, challenges, sizing, and location. In order to facilitate continued research in this field, a comprehensive literature review and classification of the studies are conducted, followed by research gaps and suggestions for future studies.

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  • 32. Anttila, Sara
    et al.
    Silva, Dalmo
    Temiz, Irina
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Oliveira, Janaína Goncalves de
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Leijon, Jennifer
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Parwal, Arvind
    Boström, Cecilia
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Power Control Strategies for a Smoother Power Output from a Wave Power Plant2019In: European Wave and Tidal Energy Conference (EWTEC), Napoli, Italy: European Wave and Tidal Energy Conference , 2019Conference paper (Refereed)
  • 33.
    Apelfröjd, Senad
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Bülow, Fredrik
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Kjellin, Jon
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Eriksson, Sandra
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Laboratory verification of system for grid connection of a 12 kW variable speed wind turbine with a permanent magnet synchronous generator2012In: EWEA 2012 Annual Event, Copenhagen, Denmark, 2012, 2012Conference paper (Refereed)
    Abstract [en]

    In this paper the first laboratory tests of the gridconnection system, connected to a resistiveload, for a vertical axis wind turbine (VAWT)with a permanent magnet generator arepresented. The system is based on a taptransformertopology with a voltage sourceinverter and an LCL-filter. The use of a taptransformer topology eliminates the need for aDC-DC converter to handle the variations inDC voltage. The harmonic content of thecurrents from experiments and simulationsperformed in Simulink using different taps onthe transformer are presented. The simulatedcurrents, fed to the resistive load, have a totalharmonic distortion (THD) of 0.5% to 0.9% forthe different taps. The experimental systemhas a current THD ranging from 1.8% to 2.8%.The difference is expected to be due tounbalances, delays and dead times in theexperimental set-up as the major THDcontribution is from harmonic orders below 11.The results show that an LCL filter can bedesigned to meet the demands on powerquality for grid connection of the system withall the taps of the tap transformer inaccordance with IEEE 519-1992.

  • 34.
    Apelryd, Caroline
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Civil and Industrial Engineering, Civil Engineering and Built Environment.
    Säsongslagra el med vätgas: Ekonomiska möjligheter för långtidslagring av grön vätgas producerad ur vindkraft2022Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The energy carrier hydrogen has a great advantage over other electricity storing techniques on the market: the ability to store electricity long-term without any geographical needs. Though today’s techniques available are of low efficiency, the interests for them are high. Hydrogen gas is versatile, and with future developments it is possibly to make great economical profit from having a hydrogen storage. This master thesis project is evaluating the possible profitability that can be made when connecting a hydrogen system to a wind farm located in Swedish electricity region SE1. 

    The system contains of production, storage and cold combustion of hydrogen with one main purpose: to produce hydrogen through electrolysis when the electricity prices are low and convert the gas back to electricity to sell when the prices are high. Four different simulations are made with a mixture of incomes: using the variety in the electricity price over a year, selling the by-products from the hydrogen system and selling pure hydrogen gas. 

    The different simulations are mainly compared through three values: levelized cost of hydrogen (LCOH), earnings before interests and tax (EBIT) and return. The results show that the LCOH -cost per produced kilo hydrogen- for all simulations are higher than other compared production methods; even higher than the price per sold kilo hydrogen. EBIT -earnings per year- show that selling pure hydrogen gas makes a major difference on the yearly profit, from (the lowest result) -52217 SEK to (the highest result) 4853306 SEK. Even though EBIT show a positive result for some of the simulations, the return on the investment is negative which makes the investment non-profitable. In a sensitivity analysis with three variables, is the one who makes the biggest difference on the return value the cost of the hydrogen storage. Lowering that cost enough would make the investment profitable. 

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  • 35.
    Apelryd, Caroline
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Civil and Industrial Engineering.
    Hrnjez, Kristina
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Civil and Industrial Engineering.
    Ranglén Svärdström, David
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Civil and Industrial Engineering.
    A modern way of traveling: Sustainable mobility in Rosendal2020Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This report aims to investigate the economical possibilities of implementing mobility services, such as electrical carpool and electrical bicyclepool, in the upcoming mobility house Brandmästaren in Rosendal, Uppsala. A model based on a travel habit survey in Uppsala has been developed in order to calculate the need of vehicles. Thereafter the financial profits are calculated depending on the need of vehicles and according to different scenarios regarding how many people that potentially will join the mobility hub. The profits are then compared to the profits from a conventional parking house, in order to decide whether the mobility system is economically viable. The results concluded the following. The most suitable mobility system for Rosendal includes 104 bicycles, 36 cargo bicycles and 94 cars. For a supplement rent of 50 SEK per user connected to the mobility center, the break-even point for the business model where bicycles are rented is when 30.56% of the residents are connected to the system. For the business model where bicycles are bought the break-even point is 18.28%. A sensitivity analysis on the number of hours the service is assumed to be used showed that the profitability would not change to a significant extent. The highest break-even point after the sensitivity analysis was 34.40%. After comparison to other mobility services in Sweden, the conclusion was that the number of connected users needed was relatively low, hence the results shows that the mobility house has the potential of being more profitable than conventional parking house.

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    Independent project 15 hp
  • 36.
    Appelstål, Sophia
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Teknisk utvärdering av befintliga och potentiella teknologier för automatisk frekvensreglering i det svenska elnätet2019Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The increasing amount of renewable energy in the power system have led to new challenges to balance supply and demand in the electric grid. To maintain the balance in the power system the system operator can activate power reserves to restore the balance at a frequency deviation. Today these reserves consist exclusively of hydropower in Sweden. With more volatile power generation new types of technologies to provide these reserves are desirable.

    The aim of this master thesis is to investigate the technical potential for using wind power, demand response and energy storage for automatic frequency control in the Swedish power system. The thesis examines the performance of the different technologies to see if they meet the technical requirements for delivering reserves set by the TSO. Moreover, the available capacity from the technologies throughout the year are estimated.

    The results show that all three technologies potentially could be used for frequency control. However, the technical requirements are not always fulfilled. In order to enable new technologies to provide power reserves some of the requirements needs to be modernized. Generally, demand response proved to have the largest available capacity for frequency control today. The study shows that demand response from industries and electric heated households could potentially provide all automatic frequency control. Modern wind turbines can be used for frequency control and for down regulation of the frequency the potential is considerable. Energy storages are not yet widely used in Sweden but with reduced costs they can play an important role in regulating the frequency in the future.  

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  • 37.
    Arding, Karin
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    In de Betou, Siri
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences.
    Making grid capacity available through heat pump control2019Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In this report the problem of constructing a bus depot with electrical buses despite the lack of grid capacity, was analyzed. A potential solution is investigated, namely smart control of heat pumps in industries. The possibility of allocating grid capacity to the bus depot by reducing power consumption in heat pumps during peak hours, is taken into consideration. The maximum amount of released capacity in an industrial area is calculated through the controlling of heat pumps. This investigation was made through simulations with a simplified building energy model (lumped capacity model) which was applied to a reference building.

    After mapping the area Boländerna and the geothermal wells located there, IKEA Uppsala was chosen as the reference building, since a third of the total number of wells were found in that area. To take the whole capacity of Boländerna into account, the model was scaled up to estimate the total, possible reduction of power. The bus depot requires 6 MW nighttime and 4 MW daytime, the total amount of electrical power that could be withdrawn, if all heat pumps were on maximum heat, in the chosen area were 0.75 MW and by controlling the heat pumps during an optimized level, the amount of 142 kW could be made available to the electric grid. 142 kW is not enough cover the need for the bus depot but it could supply the need for a slow charger to one of the buses and is therefore a possible sub-solution to the larger problem.

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  • 38. Arfvidsson, J.
    et al.
    Bjelke-Holtermann, B.
    Mattsson, J.
    Status determination and risk assessment of measures in historic buildings2018In: Conference Report: The 3rd International Conference on Energy Efficiency in Historic Buildings / [ed] Tor Broström, Lisa Nilsen and Susanna Carlsten, Uppsala University, 2018, p. 345-353Conference paper (Refereed)
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  • 39.
    Arteaga Ossa, Andres
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Evaluating the onshore wind power potential of Gotland using the New European Wind Atlas2021Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The island of Gotland has played an important role in the history of wind energy in Sweden since the very beginning. In the past decade, the island reached the maximum intermittent wind power capacity that the local grid and the current connection to the mainland can safely manage without compromising the security of supply. There were plans to install a new submarine cable, but they were finally cancelled. Nevertheless, the Swedish Government has decided to start a pilot project to make Gotland the spearhead of the energy transition. Most likely, this means that a new wind power expansion will have to take place on the island. In that context, the present study aims to estimate the onshore wind power potential of Gotland based on the New European Wind Atlas released in 2019. The starting assumption is that the potential of the island is limited to the areas appointed of national interest for wind energy by the Swedish Energy Agency. Then, the wind power potential is estimated under three technological scenarios ranging from the wind turbines operating on the island to the wind turbines recently launched on the global market. The results show that Gotland has the potential to annually produce between 2.2 TWh and 2.7 TWh of additional energy from the available wind depending on the technology used. Comparisons with real production records showed that the wind speed time series from the wind atlas proved to be useful to accurately reproduce the production patterns of real wind turbines on the island when values were aggregated at a daily or higher time scale. Additionally, mean wind speed at 100 m and the parameters of the Weibull functions fitted to the wind speed distributions were mapped for the whole island. Mean wind speeds obtained from the New European Wind Atlas for the areas of national interest on Gotland were compared to the respective values from the Swedish Wind Atlas. It was found that the latter gives systematically higher values with an average difference of 0.4 m/s within the sample.

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    MScThesisWPPM2021_AndresArteaga
  • 40. Artigas, D.
    et al.
    O’Brien, S.
    Aijazi, A.
    An unfair reputation: The energy performance of mid-century metal-and-glass curtain walls2018In: Conference Report: The 3rd International Conference on Energy Efficiency in Historic Buildings / [ed] Tor Broström, Lisa Nilsen and Susanna Carlsten, Uppsala University, 2018, p. 391-400Conference paper (Refereed)
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  • 41.
    Arumägi, Endrik
    et al.
    Chair of Building Physics and Architecture, Tallinn University of Technology, Estonia.
    Kalamees, Targo
    Chair of Building Physics and Architecture, Tallinn University of Technology, Estonia.
    Broström, Tor
    Gotland University, School of Culture, Energy and Environment.
    Indoor climate in a naturally ventilated unheated medieval church in Harju-Risti, Estonia2010In: 10th REHVA World congress Clima 2010: Sustainable Energy Use in Buildings, 2010Conference paper (Refereed)
    Abstract [en]

    Indoor climate in a naturally ventilated unheated medieval church was analysed to determine if the conditions existing suit for three medieval wooden sculptures forming the Calvary group that were decorated the church until 1958. The values of temperature and RH were measured with data loggers at 1-h intervals inside and outside the church. Ventilation measurements were performed using a passive tracer gas technique. The current study shows that there is a considerable risk in bringing back the medieval sculptures forming the Calvary group to the Harju-Risti Church without creating conditions for indoor temperature and humidity regulation. To start risk assessment it is required to maintain a RH level that prevents the risk of mould growth, reduce fluctuations of air RH annually and in the short term period, avoid of too high and too low humidity levels in church that could cause flaking, peeling and cracking of wooden sculptures.

  • 42.
    Arvidsson, Mari
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
    Analys av mellanspänningsnätet i centrala delar av Västerås stad2015Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The dependency of continuous electricity supply is high in the Swedish society today, at the same time no one is willing to pay for a too costly or over dimensioned power distribution system. The owners of the distribution systems are the ones responsible for this balance act of maintaining a high quality of electricity delivery to customers at a reasonable cost.

    In this master thesis a limited part of the primary distribution system (10 kV), owned by Mälarenergi Elnät AB and located in the city centre of Västerås, was chosen for a deeper analysis of its reliability. Its ability to handle outages of system components (N-1 and N-2 contingency analysis) was investigated to find out potential weak spots and parts of the grid that showed signs of being overdimensioned.

    The results of the performed simulations showed that in 74 % of the studied N-1 contingencies cases, consisting of outages of a bus bar in a distribution substation, the system could handle this without causing outages in other parts of the grid. For the N-2 contingencies 61 % passed the test. It was also found that one of the two included high voltage substations could alone supply the investigated part of the grid. Some cables and transformers were found to be more or less unnecessary, whereas other components proved to be overloaded in several situations.

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  • 43.
    Aslani, Mohammad
    et al.
    Univ Gävle, Dept Comp & Geospatial Sci, Gävle, Sweden..
    Seipel, Stefan
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Computerized Image Analysis and Human-Computer Interaction. Univ Gävle, Dept Comp & Geospatial Sci, Gävle, Sweden..
    A Spatially Detailed Approach to the Assessment of Rooftop Solar Energy Potential based on LiDAR Data2022In: GISTAM: Proceedings of the 8th International Conference on Geographical Information Systems Theory, Applications and Management / [ed] Cédric Grueau, Lemonia Ragia, Setúbal: SciTePress, 2022, p. 56-63Conference paper (Refereed)
    Abstract [en]

    Rooftop solar energy has long been regarded as a promising solution to cities' growing energy demand and environmental problems. A reliable estimate of rooftop solar energy facilitates the deployment of photovoltaics and helps formulate renewable-related policies. This reliable estimate underpins the necessity of accurately pinpointing the areas utilizable for mounting photovoltaics. The size, shape, and superstructures of rooftops as well as shadow effects are the important factors that have a considerable impact on utilizable areas. In this study, the utilizable areas and solar energy potential of rooftops are estimated by considering the mentioned factors using a three-step methodology. The first step involves training PointNet++, a deep network for object detection in point clouds, to recognize rooftops in LiDAR data. Second, planar segments of rooftops are extracted using clustering. Finally, areas that receive sufficient solar irradiation, have an appropriate size, and fulfill photovoltaic installation requirements are identified using morphological operations and predefined thresholds. The obtained results show high accuracy for rooftop extraction (93%) and plane segmentation (99%). Moreover. the spatially detailed analysis indicates that 17% of rooftop areas are usable for photovoltaics.

  • 44.
    Axelsson, Ebba
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Civil and Industrial Engineering, Civil Engineering and Built Environment.
    Tonell, Vera
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Civil and Industrial Engineering, Civil Engineering and Built Environment.
    Potentiella säkerhetsrisker med växelriktare för solceller2024Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis investigates the risks associated with connected inverters in solar power installations, focusing on properties owned by Vasakronan, a real estate company with 166 properties, that has invested in solar panel installations on a majority of its buildings. The thesis explores the potential security measures related to both energy and information. Energy security encompasses multiple aspects of ensuring a reliable supply of energy within an infrastructure, necessitating tools for balancing energy production and usage and minimizing dependence on single resources. Robust information security requires the preservation of confidentiality, integrity and availability, which is considered given the organization, cloud and communication security. Interviews were conducted with representatives from Vasakronan’s suppliers of inverters, IT service provider, employees and external field experts. One property served as a case study to understand the internal real estate network structure and data on energy consumption, production and prices was collected. The risk of security breaches was assessed as the sum of factors influencing the likelihood of intrusion, as well as the consequences of such breach. Interviews with employees and IT service providers revealed Vasakronan’s awareness of information security and continuous efforts to enhance it. Interviews with inverter suppliers show varying levels of commitment to information security, with a general recognition of its importance but inconsistent knowledge of mitigation strategies. Many suppliers are cautious about production location, expressing skepticism about Chinese intelligence activities. However, the current risk for Vasakronan and the Swedish power grid is considered low, though the increasing use of solar panels may heighten this risk in the future. Specific threats such as extortion attempts, are identified as more probable, potentially resulting in production interruptions and increased energy costs. The importance of risk diversification through security measures and supplier diversification is concluded from the interviews with field experts. Data analysis indicates that security breaches primarily entail economic losses for Vasakronan, while the societal consequences are seen as potentially serious but unlikely in the short term. The thesis contributes to understanding the risks and the necessity of security measures in solar power installations through an analysis of potential energy and economic consequences of data breaches.

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  • 45.
    Ayotte, John
    Uppsala University, Disciplinary Domain of Science and Technology, Mathematics and Computer Science, Department of Information Technology, Division of Systems and Control.
    Dynamic positioning of a semi-submersible, multi-turbine wind power platform2015Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    As a growing market for offshore wind power has created a niche for deep-water installations, offshore floating wind solutions have become more and more viable as a renewable energy source. This technology is currently in development and as with many new technologies, many traditional design methods are found lacking. In the multi-turbine platform design investigated, turbine units are placed closely together to conserve material use and reduce cost, however with such tightly spaced turbines; wake interaction poses a threat to the productivity and the lifespan of the installation. In order to fully capitalize on the substantial increase in available wind energy far at sea, it is important that these floating parks operate in an optimal way. The platform investigated in this report sports 3, 6MW turbines which must be positioned such that wake interference is minimized; the platform must always bear a windward heading. 

    Maneuvering ocean going vessels has been practiced using automated dynamic positioning systems in the gas and oil industry for over 50 years, often employing submerged thrusters as a source of propulsion. These systems are mostly diesel powered and require extra operational maintenance, which would otherwise increase the cost and complexity of a floating wind farm. In this paper, it is suggested that the wind turbines themselves may be used to provide the thrust needed to correct the platform heading, thus eliminating the practical need for submerged thrusters. By controlling the blade pitch of the wind turbines, a turning moment (torque) can be exerted on the platform to correct heading (yaw) relative wind direction. Using the Hexicon H3-18MW platform as a starting point; hydrodynamic, aerodynamic and electromechanical properties of the system are explored, modeled and attempts at model predictive control are made. Preliminary results show that it is possible to control the H3’s position (in yaw) relative the wind using this novel method.

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    Dynamic positioning of a semi-submersible, multi-turbine wind power platform
  • 46.
    Backlund, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy, Applied Nuclear Physics.
    Modellering, simulering och analys av kärnreaktorn BWRX-3002023Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The demand for fossil-free energy production is rising due to electrification and increased consumption in the energy system. There are also multiple climate goals to reach, to preserve the possibilities of a sustainable future.

    A response to this is the BWRX-300, a natural circulation boiling water small modular reactor (SMR) concept developed by GE Hitachi Nuclear Energy. It is currently at the forefront of study for many power utility companies around the world. For decision making it is of interest to investigate the capabilities of new facilities. This Master Thesis work's aim is to study the BWRX-300 reactor's feasibility together with evaluating and optimizing its performance using the core simulation softwares Casmo5 and Simulate5.

    This is carried out by first verifying Simulate5's natural circulation capabilities by modifying an existing forced-circulation reactor to natural circulation, then comparing simulation results to real world data. 

    Next a comprehensive model of the BWRX-300 reactor pressure vessel is modelled and validated. Equilibrium cores for 12- and 24-month cycle lengths are then simulated where key reactor performance metrics such as fuel economy, safety margins, axial profiles (of voids and pressure drop) and reactor characteristics are extracted. The effect of different fuel assembly designs in the BWRX-300 reactor core is investigated to find first core design optimums. Furthermore the decay heat removal system in the BWRX-300 is investigated. Lastly the results are used to evaluate the optimal operating mode given the current and future more dynamic projected state of the energy system. 

    The results show that there are no real technical difficulties while operating the BWRX-300 reactor for 12 or 24 months. The decay heat removal system and core flow characteristics provide abundant coolant flow to maintain long term fuel integrity during both normal and abnormal operation modes. More or less routine core design optimization work is required to obtain sufficient safety margins and improve fuel economy. It is observed that the smaller reactor core requires an increase in average fuel enrichment to maintain criticality throughout the cycle, potentially creating an incentive to raise the current licensing limit. However it is deemed possible to avoid this by conducting further fuel design optimization work.

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    Examensarbete_Erik_Backlund_BWRX300
  • 47.
    Backman, Filippa
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Civil and Industrial Engineering.
    Stafberg, Amanda
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Civil and Industrial Engineering.
    Sterner, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Civil and Industrial Engineering.
    Wesslén, Alva
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Civil and Industrial Engineering.
    Paving the Path to Self-Sufficiency: Optimizing Photovoltaic Installations on Facilities with Emphasis on Consumption Patterns and Economic Viability2023Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    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.

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  • 48.
    Backéus, Jonas
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Electrical Engineering, Electricity.
    Ombyggnad av Klockarforsen2021Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The water level at Hjälta power station in Faxälven varies depending on the water flow that passes through the power station. The varying water level causes head losses, lesser energy generation and loss of income. The varying water level is caused by a short but narrow and shallow part of the river, known as Klockarforsen. To increase the water flow and decrease the resulting head losses, it is possible to dredge the stream bed in Klockarforsen in order to achieve a greater depth. 

    By using a sonar to map the bathymetry in Klockarforsen, it has been possible to create a model of this part of the river. The model has been constructed and processed in ArcGIS and HEC-RAS, in order to examine how a dredging would affect the water level, head losses, energy generation, income and retention water levels. 

    The results show that a dredging to a depth of four or six meters could raise the water level and the head height at Hjälta power station with an average of 0.32 and 0.41 meters, respectively. During the period between 2014-2019, 1.11-3.84 GWh more energy would have been generated annually if Klockarforsen had been dredged. Which means that the income for the power station would have increased by between MSEK 0.39-1.3 per year. The increased energy generation and income are considerable, but in terms of how much energy and income is generated annually, the figures are more modest. The energy production and income increase by between 0.13-0.3 percent annually. 

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  • 49.
    Balksten, Kristin
    et al.
    Gotland University, School of Culture, Energy and Environment.
    Broström, Tor
    Gotland University, School of Culture, Energy and Environment.
    Myrin, Malin
    Tyréns AB.
    Thelin, Carl
    Tyréns AB.
    Kettunen, Rebeca
    Gotland Museum.
    Mebus, Ulrika
    Gotland Museum.
    Increased use of ruins through secured masonry and comfortable climate2010In: Proceedings of the 7th International Conference on Science and Technology in Archaeology and Conservation, Petra, Jordan, 2010Conference paper (Other academic)
    Abstract [en]

    This paper presents a unique scientific research project, funded by the KK-foundation in Sweden together with several companies participating in the project. A primary goal is to find methods to examine and take care of open masonry constructions thereby enabling an increased use of them in a safe and comfortable way without diminishing their cultural values. A second goal is to establish a long-term cooperation/network of researchers, conservators, engineers, antiquarians and craftsmen that can keep and develop the knowledge. The project takes place in year 2010 and 2011. This paper presents a model of cooperation as well as the ongoing experiment and expected results. The project is divided into three major parts:1) Description and assessment of historic masonry as load bearing structures. 2) Assessment of stone and mortar in old masonry and finding the methods to secure and preserve them. 3) The climate in the ruin with respect to comfort and preservation. The goals for the different parts of this research project are to find the best possible solutions of how to: a) Evaluate the construction of complex masonry structures to enable new additions that are appropriate with respect to statics. b) Find efficient methods to evaluate and conserve the status of the materials (stone, mortar) and walls in old masonry to grant safe accessibility. c) Create a comfortable climate in an open masonry structure without closing it. These three research areas all focus on the historic masonry which at the same time forms the climate shell, the bearer of plaster and the historical setting to the activities that are to take place in the ruin.

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    Increased us of ruins
  • 50. Banfill, P.F.G.
    Hygrothermal properties of NHL mortars2018In: Conference Report: The 3rd International Conference on Energy Efficiency in Historic Buildings / [ed] Tor Broström, Lisa Nilsen and Susanna Carlsten, Uppsala University, 2018, p. 71-79Conference paper (Refereed)
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