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  • 251. Klenz Larsen, P.
    Heat pumps for conservation heating in churches2018Inngår i: Conference Report: The 3rd International Conference on Energy Efficiency in Historic Buildings / [ed] Tor Broström, Lisa Nilsen and Susanna Carlsten, Uppsala University, 2018, s. 311-317Konferansepaper (Fagfellevurdert)
  • 252.
    Klenz Larsen, Poul
    et al.
    Högskolan på Gotland, Institutionen för kultur, energi och miljö.
    Broström, Tor
    Högskolan på Gotland, Institutionen för kultur, energi och miljö.
    Climate Control in Cultural Heritage Buildings in Denmark2011Inngår i: Developments in Climate Control of Historic Buildings: Proceedings from the International Conference "Climatization of Historic Buildings, State of the Art", 2011, s. 39-44Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Conservation heating has been used for decades to control the RH in cultural heritage buildings. But if the building is not used for living or working, heating is not needed for human comfort. The chemical decay of organic materials depends mainly on temperature, so it is better for preservation to reduce heating. The air exchange rate is related to the design of the building envelope. With rising energyprices humidity control by dehumidification may be an attractive alternative. The potential for energyefficient RH control was examined for a generic building exposed to the monthly average outsidetemperature and RH in Denmark. The indoor temperature was allowed to follow the outside average,whereas the indoor RH was controlled to 40 % 50 % 60 % or 70 %. Dehumidificationwas implemented inthree different buildings: A recent museum store, a medieval church, and an 18thcentury countrymansion. The energy consumption depends on the RH set point, theair exchange rate and the source of liquid moisture to the building. The air exchange rate related to the design of the building envelope. Single glazed windows and doors are the most important sources ofleakage to buildings. Lack of maintenance may lead to poor performance of the dehumidifier and waste energy.

  • 253.
    Klenz Larsen, Poul
    et al.
    The National Museum, Department of Conservation, Copenhagen, Denmark.
    Broström, Tor
    Högskolan på Gotland, Institutionen för kultur, energi och miljö.
    Climate control in historic buildings in Denmark2011Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In many historic buildings, conservation heating has been used to control the RH in winter. Heat pumps are much more energy efficient than direct electric heating, so this technology may be adapted for climate control. Dehumidification has not been regarded as appropriate for historic buildings due to poor regulation, but recent development in electronic hygrostats makes this technology an attractive alternative. The annual energy consumption for both control strategies was calculated from statistical meteorological data for Denmark. The most energy efficient control strategy is determined by the U-value of the building, the air exchange rate and the volume. For large buildings conservation heating with heat pump technology seems to be the most energy efficient, unless the thermal insulation is very poor. For small buildings dehumidification is more efficient unless the building is very leaky. The two strategies for climate control were tested in historic houses owned by the National Museum in Denmark and used for exhibition only in the summer season. Kommandørgården has an uncontrolled climate in summer due to open doors in the opening hours. In winter the RH is controlled to 60-70% by hygrostatic heating. Liselund is an 18th century mansion located in a romantic garden on the island Møn at the Baltic Sea. The house is open only for guided tours in the summer, and the RH is controlled all year by dehumidification.

  • 254.
    Klenz Larsen, Poul
    et al.
    Högskolan på Gotland, Institutionen för kultur, energi och miljö.
    Broström, Tor
    Högskolan på Gotland, Institutionen för kultur, energi och miljö.
    Aasbjerg Jensen, Lars
    The National Museum of Denmark, Department of Conservation.
    Energy and power demand for intermittent heating of churches2011Inngår i: Energy Efficiency in Historic Buildings, Visby, 9-11 February 2011, Visby, 2011Konferansepaper (Annet vitenskapelig)
  • 255.
    Klingborg, Klara
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Förutsättningar för elektrifierade lastbilar med eHighway inom svensk gruvindustri: En jämförelse av olika transportslag mellan Mertainen och Svappavaara2014Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    The Swedish government has a goal of achieving a fossil-free vehicle fleet in 2030. Heavy transport constitutes a significant part of Sweden's transportation sector and the vehicles are driven almost exclusively by fossil fuels. Siemens has developed eHighway, a concept for electric road systems enabling electrification of trucks, in order to reduce the environmental impact of heavy transports. This study aims to investigate the potential that eHighway has on transporting iron ore from the mine of Mertainen to a processing plant in Svappavaara. Electrified trucks are compared with conventional trucks, and diesel and electric trains.

    The evaluation was made with respect to energy consumption, environmental impact, and cost. The study also aimed to investigate whether simple standard figures are sufficient to determine which way of transport that is the most suitable. The study does not account for energy consumption from idle or from the loading and unloading of the vehicle. Thus, the study takes no account of logistical advantages and disadvantages.

    The results show that energy consumption is lowest for the cases with eHighway, where an electric 90 ton truck consumes 0.56 kWh per tonne of iron ore transported. The same value for the 60 tonne truck is 0.72 kWh. Hence, the environmental impact from eHighway is the lowest of the transport options studied. eHighway with the 90 tonne truck has emissions of 0.06 kg CO2 equivalents per tonne of iron ore transported. For eHighway with the 60 tonne truck the equivalent figure is 0.08 kg CO2 equivalents. From a cost point of view, the train options are the most favorable. The cost of the electrified locomotive, where mining trucks are running a subsection of the distance, is 4.57 SEK per tonne of iron ore transported. The corresponding cost for the diesel-powered locomotive is 7.47 SEK per tonne of iron ore transported. The cost of transporting one tonne of iron ore with eHighway is 9.31 SEK and 12.5 SEK, for the 90 tonne truck and 60 tonne truck, respectively. eHighway would be the most profitable transport solution, if two of the three factors are to be combined; 100% increase in base price of diesel, 50% subsidy of the electrical road system and if the amount of iron ore transported from Mertainen increases by 100%.

    The study is based on simple standard figures. For the comparison to be accurate further calculations and simulations are suggested. It is recommended that a complete logistics schedule is made together with the mining company or a hauling company that performs mining transports. 

  • 256.
    Klockar, Zack
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper.
    Kåhre Zäll, Olle
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper.
    Lindahl, Emil
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper.
    A study of public procurements of food: The environmental impacts and how to reduce them2019Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    There is a challenge to feed an increasing world population. Simultaneously, as more people rely on food production, ensuring a sustainable food production becomes more important. In two of the United Nations’ seventeen sustainable development goals food is mentioned, and one of the more specific targets regards making public procurements more sustainable. There are however challenges with regards to how to reduce a Swedish public procurement’s environmental impacts. This is due to some fundamental principles every Swedish public procurement must follow.

    This thesis examines the environmental impacts of two public procurements of food, regarding global warming, acidification and eutrophication. It also examines whether calculating food’s environmental impacts per serving or per kg is the more representative approach. Lastly, this thesis examines how the environmental impacts of a public procurements of food can be reduced. Consequently, a methodology of how to minimize the environmental impacts of a procurement is presented.

    Firstly, the results show that the environmental impacts per servings and per kg differ. One procurement has approximately 50-60% higher environmental impacts compared to the other when measured per serving, but approximately 2-9% lower impacts when measured per kg. The authors argue that representing the environmental impacts per serving is more accurate, since it is more correlated to nutritional values. Secondly, the results show that the environmental impacts for minimizing each environmental impact category differs.

  • 257.
    Kolar, Sandra
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    A Comparison of Wind Power Production with Three Different De- and Anti-Icing Systems2015Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    This thesis is done within the master program in energy systems engineering at Uppsala University and in cooperation with OX2. The aim was to compare the operation and performance of three different de- and anti-icing systems for wind turbines during the winter 2014/2015. The systems evaluated were de-icing with heating resistances, de-icing with warm air and anti-icing with heating resistances.

    Inconsistency in the operation of the wind turbines and the systems as well as lack of information made it hard to compare the efficiencies of the systems. The systems showed tendencies to improve the production. Especially examples during single ice events where the systems increased the power output were found, but the examples also showed possible improvements regarding the size of the systems and the duration of the de-or anti-icing cycles. Based on the approximated gain in production, during the studied time period, none of the systems could be determined to be profitable. The gain in production does however not have to be especially large for the systems to become profitable, and the results could be very different in a year with more ice, higher electricity prices or a more consistent operation of the systems.

    Important characteristics of the systems were found to be the duration of a cycle, the energy required for the operation of the system and the trigger-point for activation of the system. Additional benefits like for instance decreased loads, risk for standstill and ice throws could also be provided by the system.

  • 258.
    Kougias, Ioannis
    et al.
    European Commiss, JRC, Ispra, Italy.
    Aggidis, George
    Univ Lancaster, Dept Engn, Lancaster, England.
    Avellan, Francois
    Ecole Polytech Fed Lausanne, Hydraul Machines Lab, Lausanne, Switzerland.
    Deniz, Sabri
    Hsch Luzern, Lucerne Sch Engn & Architecture, Luzern, Switzerland.
    Lundin, Urban
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Moro, Alberto
    European Commiss, JRC, Ispra, Italy.
    Muntean, Sebastian
    Romanian Acad, Ctr Adv Res Engn Sci, Bucharest, Romania.
    Novara, Daniele
    Trinity Coll Dublin, Dept Civil Struct & Envir Engn, Dublin, Ireland.
    Ignacio Perez-Diaz, Juan
    Tech Univ Madrid, Dept Hydr Energy & Envir Engn, Madrid, Spain.
    Quaranta, Emanuele
    Politecn Torino, Dept Environ Land & Infrastruct Engn, Turin, Italy.
    Schild, Philippe
    European Commiss, DG Res & Innovat, Dir Energy, Brussels, Belgium.
    Theodossiou, Nicolaos
    Aristotle Univ Thessaloniki, Dept Civil Engn, Thessaloniki, Greece.
    Analysis of emerging technologies in the hydropower sector2019Inngår i: Renewable & sustainable energy reviews, ISSN 1364-0321, E-ISSN 1879-0690, Vol. 113, artikkel-id 109257Artikkel, forskningsoversikt (Fagfellevurdert)
    Abstract [en]

    The paper reviews recent research and development activities in the field of hydropower technology. It covers emerging and advanced technologies to mitigate flow instabilities (active and passive approach) as well as emerging magneto-rheological control techniques. Recent research findings on flow instabilities are also presented, especially concerning fluid-structure interaction and transient operating conditions. As a great number of the existing large-scale hydroelectric facilities were constructed decades ago using technologies that are now considered obsolete, technologies to achieve the digitalisation of hydropower are also analysed. Advances in the electro-mechanical components and generator design are presented; their potential role to adapt hydropower to the current operating conditions is also highlighted. The text explores current efforts to advance hydropower operation, mainly in terms of European projects. It provides a detailed overview of the recent efforts to increase the operational range of hydraulic turbines in order to reach exceptional levels of flexibility, a topic of several recent research projects. Variable speed hydropower generation and its application in pumped storage power plants are presented in detail. Moreover, revolutionary concepts for hydroelectric energy storage are also presented with the analysis focusing on underwater hydro storage and hydropower's hybridisation with fast energy storage systems. Efforts to minimise hydropower's environmental footprint are also presented via the utilisation of small-scale and fish-friendly installations.

  • 259. Koukou, T.
    et al.
    Fouseki, K.
    Heritage values and thermal comfort in Neoclassical residential buildings of Athens, Greece: Tension or co-existence?2018Inngår i: Conference Report: The 3rd International Conference on Energy Efficiency in Historic Buildings / [ed] Tor Broström, Lisa Nilsen and Susanna Carlsten, Uppsala University, 2018, s. 463-471Konferansepaper (Fagfellevurdert)
  • 260.
    Kristofersson, Filip
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper.
    Elfberg, Sara
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper.
    Maximizing Solar Energy Production for Västra Stenhagenskolan: Designing an Optimal PV System2019Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    Skolfastigheter is a municipality owned real estate company that manages most of the buildings used for lower education in Uppsala. The company is working in line with the environmental goals of the municipality by installing photovoltaic systems in schools and other educational buildings. Skolfastigheter are planning to install a photovoltaic system in a school in Stenhagen. The purpose of this study is to optimally design the proposed system. The system will be maximized, which in this study entails that the modules will be placed on every part of the roof where the insolation is sufficient. The system will also be grid connected. The design process includes finding an optimal placement of the modules, matching them with a suitable inverter bank and evaluating the potential of a battery storage. Economic aspects such as taxes, subsidies and electricity prices are taken into account when the system is simulated and analyzed. A sensitivity analysis is carried out to evaluate how the capacity of a battery bank affects the self-consumption, self-sufficiency and cost of the system. It is concluded that the optimal system has a total peak power of almost 600 kW and a net present value of 826 TSEK, meaning that it would be a profitable investment. A battery bank is excluded from the optimal design, since increasing the capacity of the bank steadily decreased the net present value and only marginally increased the self-consumption and self-sufficiency of the system.

  • 261. Krus, M.
    et al.
    Thiel, A.
    Kilian, R.
    Investigations on the influence of different types of restoration of beam ends of the floor in the Alte Schäfflerei Benediktbeuern2018Inngår i: Conference Report: The 3rd International Conference on Energy Efficiency in Historic Buildings / [ed] Tor Broström, Lisa Nilsen and Susanna Carlsten, Uppsala University, 2018, s. 108-117Konferansepaper (Fagfellevurdert)
  • 262. Krzemień, L.
    et al.
    Kupczak, A.
    Pretzel, B.
    Strojecki, M.
    Radoń, J.
    Bogaczewicz-Biernacka, E.
    Different HVAC systems in historical buildings to meet collection demands2018Inngår i: Conference Report: The 3rd International Conference on Energy Efficiency in Historic Buildings / [ed] Tor Broström, Lisa Nilsen and Susanna Carlsten, Uppsala University, 2018, s. 337-344Konferansepaper (Fagfellevurdert)
  • 263.
    Kuchler, Magdalena
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Naturresurser och hållbar utveckling.
    Post-conventional energy futures: Rendering Europe's shale gas resources governable2017Inngår i: Energy Research & Social Science, ISSN 2214-6296, E-ISSN 2214-6326, Vol. 31, s. 32-40Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Following the shale gas boom in the United States, unconventional natural gas extracted from organic-rich shale rock formations has generated increasing attention in the European Union (EU). This considerable interest has been spurred by a range of optimistic volumetric appraisals of shale gas resource potential trapped beneath the European continent. The paper critically examines rationalities and practices through which states of resource availability and recoverability are made visible, measurable, intelligible, and thus rendered governable, namely open to new fields of possibilities to act upon. By implementing the concept of socio-technical imaginaries as governmentality approach, the analysis is guided by two objectives: first, to identify visions of shale gas potential contained in a range of resource estimates; second, to scrutinize rationalities of government, that is how shale gas resources are made knowable and purposeful, as well as technologies of government that operationalize these rationalities via practices of calculation, visualization, and inscription. The paper illustrates that, these highly speculative and uncertain assessments can forge powerful volumetric imaginaries of shale gas potential that yield specific governing effects concerned with securitization of unconventional hydrocarbons availability. Consequently, these imaginaries prescribe and legitimize techno-political hopes for certain post-conventional energy futures underpinning the fossil fuel abundance narrative.

  • 264.
    Könberg, Niklas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper.
    Statistisk modellering av vindkraftsobalanser i Sveriges elområden2019Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    In a synchronous electric grid the consumption of electricity must always be met by an equal amount of generation. In the Nordic power system, this balance is first and foremost kept by the balance responsible parties in the electric markets. However, from one hour before delivery, it is the Swedish Transmission System Operator (TSO), Svenska kraftnät (Svk) together with its Nordic counterparts, who take over the responsibility. They achieve this by for example purchasing ancillary services such as Frequency Restoration Reserves (FRR) to compensate for frequency deviations. A way of explaining the frequency deviations that would have occurred without the TSO taking actions, is that they are caused by imbalances. Imbalances are the difference between measured and traded energy volumes in the bidding areas, where volumes equals HVDC-connections, consumption and different kinds of power production. In the future, these imbalances will be one of the dimensioning factors of FRR.

    The purpose of this thesis is to study the imbalances caused by wind power production and to create a model that can simulate future wind power imbalances. The long term goal is that the model will be part of a larger project whose purpose is predicting the future need of FRR. The model has been designed to use future market data, such as traded volumes and spot prices to make the predictions. The model has been developed using statistical methods in MATLAB together with another master student, who has studied consumption imbalances.

    Due to lack of deterministic correlations, the final model created was an Autoregressive-Moving-Average (ARMA) model together with a linear correlation between quarterly average traded volumes and quarterly standard deviations of the wind power imbalances. The model can recreate the historical autoregressive behaviour and the historical distribution of the imbalances to a satisfactory degree, as well as scaling up the imbalances with a correlation of 0.92. Applying future market data on the model, imbalances are expected to increase by 50\% to 180\% from today to the year 2023, depending on bidding area. However, there are uncertainties due to yearly variations in the wind power production. One conclusion is therefore that a windy year probably also will increase the required need of FRR.

    Before applying the model to evaluate the future need for FRR, the reliability used in the traded data for developing the model should be checked. A final validation of the total simulated imbalances, not just wind power imbalances, against historic data should also be performed. To develop the model further, a suggestion is to study possible spatial correlations of the imbalances between bidding areas.

  • 265. Könberg, Niklas
    et al.
    Svenson Hagström, Torkel
    Fredriksson, Jonatan
    Larsson, Eric
    Wahlqvist, Max
    Weckman, Maria
    Svedinger, David
    Kristensson, Jonathan
    Sollenberg, Markus
    Konstruktion av Savoniusturbin för projektet ARIANNA2016Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    This project aimed at dimensioning a twin-blade Savonius turbine for the neutrino research project ARIANNA, based in Antarctica. ARIANNA uses RF-sensor stations equipped with solar cells and a storage battery. During winter, insufficient solar irradiance reduces the station's live-time. The goal of the turbine was to provide a live-time of 80 % during this time of year. The generator as well as regulation controller was built to suit the battery and its Battery management unit. Simulations based on wind-speed data were done to determine the blade size required to achieve the desired live-time. Based on early simulations a Savonius turbine was built, of approximate size, to empirically examine it's coefficient of performance in different wind speeds. The results of the project is a proof of concept (POC) turbine as well as simulation modells capable of describing the different aspects of the machine. As the POC turbine did not quite produce satisfying power, sources of errors were identified from which a first prototype can be built.

  • 266.
    Landelius, Kim
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi.
    Qualification of WestinghouseBWR lattice physics methods againstcritical experiments2016Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    This thesis is part of a larger qualification effortperformed at Westinghouse Electric Sweden AB of the PHOENIX5 latticephysics code. The aim of the thesis is to validate PHOENIX5 withregards to cold criticality tests performed at the Toshiba NCAfacility in 2010-2011. For this, 26 different models were built torepresent the experiments performed by Toshiba in PHOENIX5. As anindependent reference, models were also built for the probabilisticMonte Carlo code SERPENT. The parameters examined in this thesis arethe criticality of the system, as well as the pin fission rates forselected experiments. Two different PHOENIX5 libraries were utilized,along with a HELIOS library.

    The results show that there is a Kinf trend between the differentlibraries. Furthermore, a void trend was found. This void trend waspresent for all models, including the SERPENT models. Pin fissionrate predictions give results close to those of the experiments forboth PHOENIX5 libraries. The system also proved sensitive to meshingchanges, as well as for the chosen water reflector width.

  • 267.
    Lantto, Erik
    Sveriges lantbruksuniversitet, SLU.
    Metod för beslutsstöd vid formulering och uppföljning av en kommuns klimatmål: Fallstudie Uppsalakommun2014Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    The purpose of this study is to create a method that can be used to produce decision supportdata for the climate goals of a municipality. The method should be able to demonstrate the potential for reducing energy use and greenhouse gas emissions for measures aimed at the stationary energy system in the municipality. It will be used to make long term projections of energy use and greenhouse gas emissions in order to be able to demonstrate the ability to reach climate goals. The aim was also to test the method's applicability by using the municipality of Uppsala and the Uppsala climate protocol project in a case study. Uppsala climate protocol is a project consisting of participants from business, government and organizations that voluntarily want to commit to reducing their carbon footprint by reducing their energy use and thus work to achieve the municipality's overall climate goal. Public reporting of energy use and climate impact has been studied in order to examine the nature of indicators and accounting figures that are commonly used in the field and how long-term forecasts are formulated. In connection to this, the type and sources for the kind of data needed was also examined. Tools that can be used as means for performing forecasts of energy systems development has been studied and evaluated. In the developed method the municipality’s geographical limit act as an overall system limit. The climate impact of the studied systems originates from fossil fuel combustion in the stationary energy system within the municipal boundaries, with the exception of electricity produced outsidethe municipality. At the case study of the municipality of Uppsala and the Uppsala climate protocol, most of the input data required for a baseline inventory and formulation of scenarios was retrieved from the Swedish Energy Agency, the Swedish Central Bureau of statistics and Vattenfall Heat Uppsala. Energy use and climate change forecasts was made using the simulation tool LEAP (Long-range Energy Alternatives Planning System). Two scenarios were modeled; a reference scenario describing the energy system's long-term development if no further measures is taken in addition to those already decided and an actor scenario describing an alternative development of the energy system based on additional measures to reduce climate impact. Results were reported for a base year, 2020 and 2030. For 2020 the results showed that greenhouse gas emissions from the stationary energysystems becomes 1.7 tonnes CO2-e per capita in the actor scenario, compared with 2.4 tonnes of CO2-e per capita in the reference scenario. The overall climate goal of the municipalityof Uppsala and Uppsala climate protocol is that total emissions should not exceed 4.8 tonnes CO2-e per capita by 2020. The case study shows how the method can be used to make projections of energy use and climate impact from the stationary energy system within a municipality. It also shows how the method can be used to compare measures for achieving climate goals.

  • 268.
    Larsson, Jonas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Undersökning av solcellspotentialen för golfverksamheter i Sverige2015Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    Photovoltaic Systems in Sweden has longbeen heavily dependent on subsidies and grants to bring in a profit for the investor. Production of excess electricity is a major reason for this as the compensation for excess electricity today is low. However, there are businesses that have an electricityneed that are particularly suitable for solar electricity. These businesses have an electricity demand when the sun shines the brightest and if the Photovoltaic System is properly scaled, the excess electricity can be minimized. A golf club is that kind of a business and this thesis aims to examinate the solar power potential for golf businesses in Sweden.

    Nine golf clubs was selected from different locations in Sweden. The load profiles from these golf clubs was simulated in the software HOMER against solar radiation data from each site. The system sizes that produces 5% excess electricity was calculated for each club. Finally the profitability for these systems was evaluated.

    The result shows that the golf clubs in Sweden can make profitable investments in PV systems without subsidies and grants. When the excess production is allowed to be 5% of the total production, solar electricity covers about 20 % of the yearly electricity need. For many of the clubs, the netpresent value is greater than the investment after 40 years. This means that the investment has more than doubled its value. Production price will be about 80 Swedish cents per kWh and the payback time is estimated to be 18 years.

  • 269.
    Larsson, Josefine
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Effect on district heating systems in Dalarna County from energy efficiency measures in buildings - a scenario study to 20502012Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    Energi Intelligent is a program in Dalarna County with the purpose of finding ways of enhancing the efficiency of energy use and thereby be able to reach a more sustainable use of energy resources[1]. The basis of this program is the energy goal that has been prepared for Dalarna County published in Dalarnas miljömål[2].  The energy goal is divided into a number of intermediate goals, the sixth, Delmål 6, is to reduce energy consumption in buildings with 50 percent until 2050, and with 30 percent until 2025[3].

     

    There are often a large number of different sectors involved that have got differing opinions and intentions. This makes the task far more complex than simply reducing energy consumption, because energy efficiency is one goal and that would mean that power companies would not be able to continue increasing their profit.

     

    The aim of this project was to analyze the effects on energy production when reducing the use of heat demand in buildings until 2050. The district heating systems constitutes the main part of heating of buildings in the county and that is why it has been analyzed in this project.

     The simulation tool that was suggested in the declaration of the thesis work was LEAP, the Long range energy alternative planning system tool for simulating different scenarios over years from the base year of the model.  The idea was to build energy models of Falun district heating system and Borlänge district heating system in LEAP. Scenarios were defined for the energy goals and then simulated in a model of district heating system. Simulation of the district heating systems were made from the scenarios; reducing the district heating production with 30 percent until 2025 and 50 percent until 2050. The results from the analysis showed that for Falun district heating system the reduction of district heat demand will lead to decreased heat and electricity production and there will be no need for further investment. In Borlänge district heating system capacity is lower than the total capacity of all the available waste resources and there have been discussions about investing in a third municipal waste incineration boiler that would increase the total capacity so Borlänge district heating system could have waste incineration that covers the resources of the fuel cost favorable municipal and industrial waste.

  • 270.
    Larsson, Lovisa
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Markanvisningstävling som styrmedelför att främja solelinstallationer: En fallstudie av stadsdelen Rosendal, Uppsala2016Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    This thesis evaluates the PV potential of a new district in the town Uppsala calledRosendal. Year 2014 the Uppsala municipality decided on a new environmentalprogram that consists of goals for the region in several different subjects. One of thesubjects is solar power and installed PV capacity in the municipality. To reach the goalof 30 MW installed PV capacity before 2020 one important part is that new buildingsinclude PV systems when they are built. In this thesis the difference in level ofambition from the developer regarding solar power has been evaluated comparedwith the optimal PV production and what it would take to realize the solar powergoal. All calculations have been done with MATLAB. Five different developers andprojects have been included in the study which estimates that the level of ambition is18 kW of installed PV capacity when all developers are counted for. The optimal PVcapacity is calculated to be 308 kW and an installation rate of ~0.5 kW per householdin the project area. The demand to be able to reach the solar power goal is alsocalculate to be 0.5 kW. The conclusion of this thesis is that the ambitions from thedevelopers regarding PV production is too low to reach the goal but if the optimalcase would be considered it is possible to install PV system in a level that is required.

  • 271. Larsson Sihm, André
    Melting points of binary and ternary eutectic chloride salts: MD simulations on LiCl-NaCl-KCl and its binary constituents2019Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    This thesis investigates how well the Alexandria (WBK) force-field can predict themelting point for multi-cation chloride salts with molecular dynamic (MD) simulationsin Gromacs 4.6.7. Researched is the eutectic ternary salt LiCl-NaCl-KCl(53.5-8.6-37.9 mol%) and its binary eutectic constituents(NaCl-LiCl: 22.5-77.5, KCl-NaCl: 50-50, LiCl-KCl: 58.5-41.5 mol%).

    The choosen salt mixtures are all promising candidates for use as electrolyte in liquidmetal batteries, a potential future power grid storage system.

    Simulation of the ternary salt's bulk at 298 K over 100 simulations with its ionsdifferently arranged within the crystal lattice for each simulation all resulted in stablecrystalline structures. This indicates that the WBK force-field properly andconsistently can produce stable crystalline structures not just for pure salts, but alsowithin multi-component ones.

    The melting point for the ternary and first binary combination was determined to550 K (12.9 % lower than experimental) and 950 K (12.6 % higher than experimental).

    No melting point could be determined for the last two binary combinations, as theymelted in their entire simulated temperature intervals. The ternary salt showcased acrystalline/amorphous mixture at solid phase temperatures when simulating with thesolid/liquid coexistence method. These simulation anomalies show that modeling ofmulti-cation chloride salts may not be as straight forward as it is with pure salts,despite using a force-field parameterized specifically for alkali halides.

  • 272.
    Larsson, Simon
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper.
    Reviewing electricity generation cost assessments2012Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    Studies assessing the electricity generation cost of various power generating technologies are becoming increasingly common and references to such studies can often be heard in the public debate. Different studies do however often present significantly different results. This is a problem as electricity generation cost assessments are important when it comes to choosing and designing future energy systems. In this thesis, existing electricity generation cost assessments are reviewed and issues and differences with current methodologies are investigated. As many of the reviewed studies lack detailed sensitivity analyses, an electricity generation cost model has been implemented in order to shed some light on the sensitivity in the produced results.

    The thesis shows that different methodological approaches and assumptions have a significant impact on electricity generation cost results. The habit of generalising electricity generation costs in a public context can also be questioned. Generation costs tend to be site-specific and sensitive to changes in input parameters.

    Another finding is that current methodologies are not suitable for comparing intermittent and dispatchable power generating technologies. The reasons are missing electricity system cost perspective and failure to account for differences in production profiles.

  • 273.
    Larsson, Simon
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Globala energisystem.
    Fantazzini, Dean
    Moscow School of Economics.
    Davidsson, Simon
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Globala energisystem.
    Kullander, Sven
    Royal Swedish Academy of Sciences.
    Höök, Mikael
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Globala energisystem.
    Reviewing electricity production cost assessments2013Inngår i: Renewable & sustainable energy reviews, ISSN 1364-0321, E-ISSN 1879-0690, Vol. 30, s. 170-183Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A thorough review of twelve recent studies of production costs from different power generating technologies was conducted and a wide range in cost estimates was found. The reviewed studies show differences in their methodologies and assumptions, making the stated cost figures not directly comparable and unsuitable to be generalized to represent the costs for entire technologies. Moreover, current levelized costs of electricity methodologies focus only on the producer's costs, while additional costs viewed from a consumer perspective and on external costs with impact on society should be included if these results are to be used for planning. Although this type of electricity production cost assessments can be useful, the habit of generalizing electricity production cost figures for entire technologies is problematic. Cost escalations tend to occur rapidly with time, the impact of economies of scale is significant, costs are in many cases site-specific, and country-specific circumstances affect production costs. Assumptions on the cost-influencing factors such as discount rates, fuel prices and heat credits fluctuate considerably and have a significant impact on production cost results. Electricity production costs assessments similar to the studies reviewed in this work disregard many important cost factors, making them inadequate for decision and policy making, and should only be used to provide rough ballpark estimates with respect to a given system boundary. Caution when using electricity production cost estimates are recommended, and further studies investigating cost under different circumstances, both for producers and society as a whole are called for. Also, policy makers should be aware of the potentially widely different results coming from electricity production cost estimates under different assumptions.

  • 274.
    Leach, Christopher
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper.
    Multi-Actor Multi-Criteria Decision Analysis of Wind Power Community Benefit Schemes2018Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    Abstract [en]

    Community benefit schemes in the context of wind power are increasingly provisioned by developers as a means of generating local socio-economic and environmental value, fostering social relations and strengthening acceptance. Determining an appropriate and effective benefit scheme can prove challenging, given the variation of exposed stakeholders, diversity in schemes and the lack of decision making guidance. A multi-criteria decision aid framework for identifying the most appropriate scheme(s) for a hypothetical wind power project is developed. The framework is based on AHP and PROMETHEE II decision support tool, where six (6) alternative schemes are assessed using the preferences of five (5) stakeholders and their relevant criteria. The framework was applied to a fictitious development on the island of Gotland. Results from the applied example indicate that the most locally suited outcome was the ownership based models. It is anticipated that the methodological framework can help identify the scheme(s) that respond to the needs and preferences of the locality. Moreover, a decision making platform of this nature can provide practical support to developers, communities and local authorities, and contribute to a more effective and efficient development and negotiation process surrounding community benefit schemes.

  • 275.
    Ledinek, Dorothea
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Donzel-Gargand, Olivier
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Sköld, Markus
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Keller, Jan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Edoff, Marika
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Effect of different Na supply methods on thin Cu(In,Ga)Se2 solar cells with Al2O3 rear passivation layers2018Inngår i: Solar Energy Materials and Solar Cells, ISSN 0927-0248, E-ISSN 1879-3398, Vol. 187, nr 1, s. 160-169Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this work, rear-contact passivated Cu(In,Ga)Se2 (CIGS) solar cells were fabricated without any intentional contact openings between the CIGS and Mo layers. The investigated samples were either Na free or one of two Na supply methods was used, i) a NaF precursor on top of the Al2O3 rear passivation layer or ii) an in situ post- deposition treatment with NaF after co-evaporation of the CIGS layer. The thickness of the ALD-Al2O3 passi- vation layer was also varied in order to find an optimal combination of Na supply and passivation layer thickness. Our results from electrical characterization show remarkably different solar cell behavior for different Na supplies. For up to 1nm thick Al2O3 layers an electronically good contact could be confirmed independently of Na deposition method and content. When the Al2O3 thickness exceeded 1 nm, the current was blocked on all samples except on the samples with the NaF precursor. On these samples the current was not blocked up to an Al2O3 layer thickness of about 6 nm, the maximum thickness we could achieve without the CIGS peeling off the Al2O3 layer. Transmission electron microscopy reveals a porous passivation layer for the samples with a NaF precursor. An analysis of the dependence of the open circuit voltage on temperature (JVT) indicates that a thicker NaF precursor layer lowers the height of the hole barrier at the rear contact for the passivated cells. This energy barrier is also lower for the passivated sample, compared to an unpassivated sample, when both samples have been post-deposition treated.

  • 276.
    Ledinek, Dorothea
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Salome, Pedro
    Int Iberian Nanotechnol Lab, P-4715330 Braga, Portugal.
    Hägglund, Carl
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Edoff, Marika
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Rear contact passivation for high bandgap Cu(In,Ga)Se2 solar cells with varying absorber thickness and flat Ga profile2017Inngår i: 2017 IEEE 44th Photovoltaic Specialist Conference (PVSC), IEEE , 2017, s. 796-801Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this study, six samples of Cu(In,Ga)Se2 solar cells with a high band gap (1.31 eV) and a flat Ga profile ([Ga]I([Ga]+[In]) approximate to 0.60) were produced. For every nominal absorber thickness of 0.5, 1.0 and 1.5 gm, the Mo rear contact of one sample was passivated with a 27 nm thick Al2O3 passivation layer with point contact openings, while the other sample's rear contact remained unpassivated. For the passivated cells, mainly large gains in the short circuit current lead to an up to 21%, 13% and 14% (relative) higher power conversion efficiency compared to the unpassivated cells.

  • 277.
    Lee-Jones, David
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper.
    FEASIBILITY STUDY OF BUILDING INTIGRATED HYBRID SOLAR PV AND WIND POWER SYSTEMS: A CASE-STUDY ON THE SWEDISH ISLAND OF GOTLAND2016Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    Abstract [en]

    This Thesis carries out a high level analysis of the financial feasibility of building integrated small scale renewable energy systems. A number of alternative system configurations have been established that include a mixture of grid connected wind turbines and solar photovoltaic (PV) applications to provide electricity to meet the demand of the base load demand of the building, with any occurrence of excess production sold back to the grid. A methodology to account for an analysis of their feasibility has been developed. The methodology is based on a well-known clean energy system analysis tool, namely RETScreen. The local climate data has been extrapolated and calculations carried out using the RETScreen database and software. From this, the maximum initial financial investment of the systems has been estimated, based on a given financial hurdle rate (i.e. the annual financial interest return on initial investment) and the savings and income generated from reduced grid electricity consumption and selling electricity back to the grid. The methodology is applied to an academic building located in the city of Visby on the Swedish island of Gotland, with a hurdle rate set to 7%. Electricity generation scenarios include 4 systems with 3.6 - 15.2 kW of wind, and 21.5 kW of PV located on a flat roof of a building containing office space, lecture rooms and a large student break area. Of the considered systems, it was concluded that the most feasible system was the system with a mixture of 15.2 kW of installed wind capacity and 21.5 kW of installed solar PV capacity. In addition, the results suggested that even with the grant system in place in Sweden for solar PV systems, the solar PV part of the systems would likely not be feasible. Therefore it was suggested that future work in this area should involve an investigation of a purely wind power system be carried out, as well as to investigate the hourly demand of the building and the hourly potential supply of the renewable energy system. The building permit process, installation and energy resources and requirements and installation should also be researched further, including taking actual energy consumption readings from the building and installing climate measuring instruments in the proposed positions on the roof in order to achieve more accurate input data.

  • 278.
    Leena, Grandell
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Naturresurser och hållbar utveckling.
    Höök, Mikael
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Naturresurser och hållbar utveckling.
    Assessing Rare Metal Availability Challenges for Solar Energy Technologies2015Inngår i: Sustainability, ISSN 2071-1050, E-ISSN 2071-1050, Vol. 7, nr 9, s. 11818-11837Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Solar energy is commonly seen as a future energy source with significant potential. Ruthenium, gallium, indium and several other rare elements are common and vital components of many solar energy technologies, including dye-sensitized solar cells, CIGS cells and various artificial photosynthesis approaches. This study surveys solar energy technologies and their reliance on rare metals such as indium, gallium, and ruthenium. Several of these rare materials do not occur as primary ores, and are found as byproducts associated with primary base metal ores. This will have an impact on future production trends and the availability for various applications. In addition, the geological reserves of many vital metals are scarce and severely limit the potential of certain solar energy technologies. It is the conclusion of this study that certain solar energy concepts are unrealistic in terms of achieving TW scales.

  • 279.
    Legnér, Mattias
    et al.
    Uppsala universitet, Humanistisk-samhällsvetenskapliga vetenskapsområdet, Historisk-filosofiska fakulteten, Konstvetenskapliga institutionen, Kulturvård.
    Leijonhufvud, Gustaf
    Uppsala universitet, Humanistisk-samhällsvetenskapliga vetenskapsområdet, Historisk-filosofiska fakulteten, Konstvetenskapliga institutionen, Kulturvård.
    A Legacy of Energy Saving: The Discussion on Heritage Values in the First Programme on Energy Efficiency in Buildings in Sweden, c. 1974–19842019Inngår i: The Historic Environment: Policy & Practice, ISSN 1756-7505, E-ISSN 1756-7513, Vol. 10, nr 1, s. 40-57Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The paper analyses the ‘energy savings plan for existing buildings’ (EBB) introduced in Sweden after the first oil crisis of 1973, and how effects of policies on the built heritage were perceived and communicated to a wider public. A conflict between conservation aims and energy efficiency was constructed for the first time in Sweden. The programme was a huge investment made by the government to reduce the import of oil. At first, little consideration was taken to the fact that heritage values might be at risk when giving property owners financial incentives to retrofit their houses. Soon increasing knowledge about the existing building stock showed that older houses were not necessarily energy inefficient. An information campaign launched by protagonists of building conservation encouraged property owners to direct measures to the interiors of buildings, thus saving the exterior character of not just single buildings but also complete neighbourhoods. Towards the end of EBB, the field of conservation had become a more articulated voice when it came to influencing measures aiming at increased energy efficiency. Finally, the paper discusses how values constituted in the 1970s affect policy and practice today.

  • 280.
    Leijon, Jennifer
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Simulation of a linear wave energy converter with different damping control strategies for improved wave energy extraction2016Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    In this project, the wave energy converter (WEC) designed at Seabased AB and Uppsala University was modelled in the program MATLAB. In order to increase the average output power, the WEC should be controlled. Therefore, the simulation tool was used to investigate damping strategies where the damping coefficient was changed at different times of the wave period. The tests showed that a suitable damping strategy, matched to the sea state at the specific location of the site and the overall WEC design, increases the average output power, as well as may protect the WEC from damages. This can lead to a more sustainable WEC system, which may contribute to the increasing demand of renewable energy solutions.

  • 281.
    Leijon, Jennifer
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Sjölund, Jonathan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Ekergård, Boel
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Boström, Cecilia
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Eriksson, Sandra
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Dolguntseva, Irina
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Leijon, Mats
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Linear Generator with Different Types of Ferrite Permanent Magnets for Wave Energy Conversion2017Konferansepaper (Fagfellevurdert)
  • 282.
    Leijon, Mats
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Ekergård, Boel
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Apelfröjd, Senad
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    de Santiago, Juan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Bernhoff, Hans
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Waters, Rafael
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Eriksson, Sandra
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    On a Two Pole Motor for Electric Propulsion System2013Inngår i: International Journal of Engineering Science and Innovative Technology, ISSN 2319 - 5967, Vol. 2, nr 1, s. 99-111Artikkel i tidsskrift (Fagfellevurdert)
  • 283.
    Leijonhufvud, Gustaf
    Högskolan på Gotland, Institutionen för kultur, energi och miljö.
    Energideklarationer och kulturvärden2006Independent thesis Basic level (degree of Bachelor), 15 poäng / 22,5 hpOppgave
    Abstract [en]

    The European Directive on the Energy Performance of Buildings 2002/91/EC will soon be implemented in Sweden. Legislation about energy certificates will probably take effect in Sweden during October 2006. In this thesis I try to investigate if and how cultural values in the building stock will be affected by the introduction of compulsory energy certificates for existing buildings. My aim is to find out how the procedures and methods involved in the process of acquiring the certificates can be adjusted in a way that will preserve the cultural values. The subject of energy saving and its impact on historic building is briefly presented in the first chapters. Relevant Swedish legislation is described. The new Swedish legislation about energy certificates is summarized, with focus on the parts that might be important considering historic buildings. Three case studies constitute the core of the investigation. Energy certificates are constructed for three different one-family houses. The method that is supposed to be used when constructing the energy certificates is not yet established in Sweden, but the basis is somewhat decided. The results from each energy certificate have then been discussed with preservation issues in mind. Especially the recommendations for cost-effective improvements of the energy performance that are presented in the certificates are discussed. Undoubtedly, there is a potential for energy saving in historic buildings. Most culturally valuable buildings were built with constructions which are inferior to modern when it comes to energy performance. In the case of one- and two-family houses measures that affect the building shell (i.e. retrofitting and exchange of windows) will be proven cost-effective and therefore suggested in the certificates. We know that these kinds of measures are prone to affect the cultural and aesthetic values of historic buildings. This is well known in Sweden since the 1970´s, when many careless energy saving measures were made in connection with the oil crisis. The main conclusion made is that the independent experts who are supposed to carry out the work to produce the energy certificates should have a basic understanding of the problems involved. This necessary qualification should be applied for all categories of buildings, not only monumental ones. In the case of monumental buildings, where the cultural values are more obvious, it is in fact easier to be aware of the risks involved.

  • 284.
    Lenner, Johan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Solar cells on hydro power plants: A feasibility study2015Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    Parts of the auxiliary power systems at Fortum's hydro power stations are usingdirect current, which is fed from the generators at the plant and converted byrectifiers. As photovoltaic solar cells produce direct current there are severalhypothetical advantages to use solar power for the auxiliary power supply, e.g.enabling more of the power from the generator to be sold to the grid. It eliminatesthe need of an inverter, conversion losses are avoided and less load is put on therectifiers. However the exclusion of an inverter also prevents the solar cells to have adirect connection to the grid, which in turn makes them ineligible for the Swedishgovernmental solar power investment support program. The lesser load on therectifiers will not affect their lifetime according to manufacturers and thus achieves noeconomic gain. Avoiding conversion losses will increase the gain from the producedelectricity by enabling even more power to be sold to the grid. The economic gainfrom avoiding conversion losses is however too small to gain any feasibility in a smallsolar power installation at a hydro power plant, as the small size will make itexpensive in terms of investment per Wp.

  • 285. Leppänen, Linnéa
    Energi- och klimatsimulering för nybyggnation av äldreboende med jämförelse mot BBR-krav och Miljöcertifiering2018Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    A nursing home for old people is going to be built in Edsbyn, a community in Hälsingland, Sweden. The building needs calculation of energy use to receive a building permit. Seven different indicators in Miljöbyggnad were also examined. Miljöbyggnad is a Swedish environmental certification a building can acquire. In the project some changes in selected parameters of the buildings constructions and installations are examined to see how it affects the need of power to heat and the indoor climate. To obtain answers some simulations in IDA-ICE simulation program have been done together with a literature study.

    The results show that the building fulfills the requirements of specific energy use and mean value of the U-values that are set in BBR24. The building also fulfills the requirements of the number of primary energy and mean value of the U-values that is set in BBR25. Of the seven indicators in Miljöbyggnad that were examined two received the grade GOLD, three received SILVER and two received BRONZE. When building parameters are varied the results show that the largest difference in heating power is when changing the thickness of insulation and the largest difference in PPD, Predicted Percentage Dissatisfied, is when changing the indoor temperature.

  • 286.
    Lewander, Christian
    et al.
    Högskolan på Gotland, Institutionen för humaniora och samhällsvetenskap.
    Westberger, Jon
    Högskolan på Gotland, Institutionen för humaniora och samhällsvetenskap.
    Finansiering av vindkraft: fallstudie av Lau Vind AB2012Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    The wind power increase of Gotland as well as other parts of Sweden during the last ten year period has meant that this renewable energy source has increased its share over other fossil sources. The year of 2011 became the first when the wind power produced more energy than an average nuclear reactor. Now that wind power is in an expansive phase, the land issue will be of great interest. Land with good wind resources will be of interest to wind energy developers. 

    The problems that this essay is based on are; how can landowners altering the economic conditions at a wind power establishment? What opportunities and obstacles exist for landowners who choose to set up wind power on their land? The purpose of this essay is to highlight the economic conditions that exist for landowners for the establishment of wind farms, with regard to compensation for the leasing and return on invested capital. The authors will also clarify the difficulties and opportunities arising from the process at an imaginary wind power establishment, which have emerged through interviews and research articles. The primary sources consist of interviews with actors for a planned wind farm in southeast Gotland, as well as representatives of a trade association of companies working with wind power. Interviews were also made with a bank, where the experience in question funding for wind energy has been important for our problem as well with a wind turbine manufacturer for real facts about wind turbines. 

    Landowner’s interest in wind energy as a long term investment has in Lau on Gotland resulted in a project where local landowners have chosen to form a joint company to invest in a wind farm, with the goal that the park generally will be owned by local residents in the parish. Conclusions to be drawn from this study is that landowners who form a joint company, in this case Lau Wind AB will open an opportunity for landowners to take a larger share of the ownership and profits as wind power turbines on their land supplies. But also for locals who have opportunity to become owners of the wind through the purchase of shares in wind farm.

  • 287.
    Liapodimitris, Dimitrios
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper.
    VESSEL FLEET OPTIMISATION FOR OFFSHORE WIND POWER MAINTENANCE2017Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    Abstract [en]

    Wind power has been a leading energy source in the renewable energy sector. The offshore wind power industry is rapidly growing, having the advantages of great wind resources, with minimum impact on residential areas; however, the high O&M costs add significantly to the LCOE, and present a challenge to the project developers and operators. The objective of this Thesis is to develop an optimisation method aiming to optimise the O&M vessel fleet in terms of its size and mix, and implement it into a spreadsheet-based tool. At first, a review on the available literature was conducted, in order to establish the theoretical background on the topics of maintenance, optimisation and O&M vessels, and identify the O&M strategies used in offshore wind power. The optimisation method developed focuses on the implementation of different O&M strategies,and is mainly based on the vessel contracts strategy, which aims to acquire lease contracts of various vessel types, including helicopters, available in the market to support the maintenance activities of an offshore wind farm. The model developed consists of calculation modules and introduces a 5-stage weather data filtering process for the estimation of the operational weather window, a WT components' failures forecast method, and a 2-stage optimisation process. The model was applied on a case study of a fictitious offshore wind farm, by using measured and realistic input data, in order to examine its efficacy. The model's outputs generated presented the optimal O&M vessel fleet for three different scenarios (mean, best case, and worst case), together with the optimal allocation of the failure repairs to each O&M vessel, and the corresponding O&M costs.

  • 288.
    Lind, Joakim
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Kyla på Swedavia Stockholm Arlanda: Kartläggning av nuvarande fjärrkylasystem och framtida utvecklingsmöjligheter2013Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    Arlanda airport is Sweden’s largest airport. The demand for comfort cooling of the airport’s buildings is high and is mainly provided by district cooling. District cooling is based on the same principle as district heating. A centralized production facility for the district cooling offers advantages from both an environmental and operational perspective. Swedavia, which owns, operates and develops the airport, therefore advocates that district cooling always should be the first hand choice to meet the demand of comfort cooling. In the current situation the district cooling system at Arlanda is operated at its full capacity. This makes additional connections impossible. The purpose of this thesis has been to examine the possibilities of increasing the deliveries of comfort cooling through Arlanda Airport district cooling system. This report describes Arlanda airport’s district cooling system and its development prospects. District cooling requires a system perspective. It is important that all components in the system interact to achieve an optimized use of the distributed cold water. In addition this report also addresses the parameters that affect a building's cooling load and the measures that can reduce the power load, which is the main parameter that limits the number of users on the district cooling network.

  • 289.
    Lindberg, Irene
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Undersökning av förskolan Temmelburken certifierad enligt Miljöbyggnad: Termiskt klimat, energianvändning och höjning av certifieringsnivån2014Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    WSP building physics in Stockholm has certified the preschool Temmelburken in Bromma with the system of certification Miljöbyggnad. The rating of the building became BRONZE. In this thesis the preschool has been investigated with respect to the three areas: thermal climate, use of energy and improving of the level of certification.

     

    The thermal climate at the preschool has been investigated by a questionnaire survey and by measurements in order to do comparisons between the results from the two investigations as well as with the results of the simulations that WSP has done at the certification of the preschool. The differences between the results from the simulations and the questionnaire survey for winter as well as from the measurement performed with a comfort meter the 19th of March are concidered to be reasonably small since they give rise to the same rating according to Miljöbyggnad.  

     

    Operational data for the use of energy for the preschool have been obtained in order to do comparisons with simulations performed by WSP and Svenska Besiktningar AB. The comparison shows that the simulated values for the specific use of energy are lower than what the real specific use of energy would be for the preschool, since just the operational data for the heat energy is higher than the simulated values.

     

    At the investigation of the possibility of improving the level of certification it was found that the rating of the preschool can be raised from BRONZE to SILVER by improving the ratings of the ”thermal climate summer” and the ”daylight”. The simulation program VIP-Energy was used to investigate how the different solar shadings: blind, marquis and fixed screen affected the cooling need of the second floor of the preschool. Possible actions for increasing the inlet of daylight are discussed. Two measures were identified: increasing the glass area and changing to windows with higher transmission of light. If the information about the use of energy which has emerged in this thesis is considered it will not be sufficient to only improve the ”thermal climate summer” and the ”daylight” in order to improve the level of certification.

  • 290.
    Lindberg, Oskar
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper.
    Birging, Alfred
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper.
    Solbruksplan för effektiv utbyggnad av solcellsparker: Kartering genom elnätssimulering och geografisk analys2019Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    One of the major challenges that the energy system is facing is how 100% renewable electricity generation should be designed and controlled. So far, utility-scale solar photovoltaic (PV) parks, have dominated the international market and is expected to grow in Sweden. In order for this expansion to thrive it needs to be done in a resource and system-efficient way. In this study, a methodology for a utility-scale solar guide (from Swedish 'Solbruksplan') is developed. This is done through electrical grid simulations and geographical analysis in order to find strategic locations for PV parks, without grid reinforcements, using Herrljunga municipality as a case study. The electrical grid is analyzed through power flow simulations and the geographical assessment is done using multi-criteria analysis (MCA) with a Boolean approach. Three different sizes of PV parks, 1, 3, and 5 MW, were simulated and assessed. The results show that 8.6% of the total area in the municipality, or 78,500 square meters per substation, is suitable for locating 1 MW PV parks. The majority of the grid’s substations (about 90%) also have enough capacity for a PV park of 1 MW. Furthermore, parts of the grid can host PV parks of 3 and 5 MW, but limited to the proximity of the urban areas. However, 3 and 5 MW PV parks are not suitable due to limited land availability in urban areas. The results highlight that a utility-scale solar guide can be used to effectively identify possible areas for PV parks, considering geography and grid capacity. Hence, it can function as a tool for utility companies, municipalities, PV companies and land-owners to find resource and system-efficient locations for PV parks.

  • 291.
    Lindberg, Sofie
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Solavskärmning i kommersiella fastigheter: En fallstudie av en befintlig kontorsfastighet med olika fönster- och solavskärmningsåtgärder2016Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    This thesis analyzes different window and solar shading alternatives in office buildings with respect to energy, comfort and economy. The thesis is conducted as a case study, where an existing office building in Stockholm is simulated using the software IDA ICE. The building’s original double pane windows without solar shading are used as reference windows. These windows are subsequently compared to three different window and solar shading alternatives: an additional glazing and solar film, new energy efficient window with included solar protection and vertical awning with screen fabric. The results show that the energy savings were 85 MWh for the additional glazing and solar film, 160 MWh for new energy efficient window and 5 MWh for the vertical awning with screen fabric. The best overall result was achieved by the additional glazing and solar film due to good performance in all three categories. The new energy efficient window with included solar protection had the best results regarding both energy and comfort, but lacked in profitability. The vertical awning with screen fabric had the best results in limiting the use of cooling. For the case study, the additional glazing and solar film provided the best results. In order to determine the optimal window and solar shading alternative with respect to energy, comfort and economy for other office buildings one has to look at the individual conditions for each building as several aspects are important.

  • 292.
    Lindblad, Liselotte
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Baudoin, Antoine
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Leijon, Mats
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära. Univ Southampton, Engn & Environm, Energy & Climate Change, Southampton, Hants, England..
    Measurement System For Wave Energy Converter - Design And Implementation2014Inngår i: 33Rd International Conference On Ocean, Offshore And Arctic Engineering, 2014, Vol 9A: Ocean Renewable Energy, AMER SOC MECHANICAL ENGINEERS , 2014Konferansepaper (Fagfellevurdert)
    Abstract [en]

    A Wave Energy Converter (WEC) measurement system has been constructed and installed with the purpose to measure, log and evaluate the WEC's performance during operation at sea. The WEC is to be deployed at Uppsala University's wave power research site in Lysekil on the west coast of Sweden. In designing such a system the key research objectives has been (1) to study the risk of overheating due to high currents in the stator windings, (2) to evaluate how the WEC's outer structure withstands drag and bending forces from the buoy line and (3) to construct a detection system which indicates if water leaks into the generator. The measurement system was designed to collect data essential to study these key objectives. Transducers were used to measure: buoy line force, translator position, phase currents, bending and tensile strain on the generator hull, water level inside generator and the temperature at multiple places inside the generator. The measurement system has been installed and calibrated in the WEC. Furthermore, the design has been evaluated in lab experiments in order to verify the function and accuracy of the different measurements. This paper presents the underlying research objectives for developing the WEC generator measurement system, together with a description of the technical implementation.

  • 293.
    Lindblom, Ellen
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad mekanik, Byggteknik.
    Almquist, Isabelle
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad mekanik, Byggteknik.
    Data-Driven Predictions of Heating Energy Savings in Residential Buildings2019Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    Along with the increasing use of intermittent electricity sources, such as wind and sun, comes a growing demand for user flexibility. This has paved the way for a new market of services that provide electricity customers with energy saving solutions. These include a variety of techniques ranging from sophisticated control of the customers’ home equipment to information on how to adjust their consumption behavior in order to save energy. This master thesis work contributes further to this field by investigating an additional incentive; predictions of future energy savings related to indoor temperature. Five different machine learning models have been tuned and used to predict monthly heating energy consumption for a given set of homes. The model tuning process and performance evaluation were performed using 10-fold cross validation. The best performing model was then used to predict how much heating energy each individual household could save by decreasing their indoor temperature by 1°C during the heating season. The highest prediction accuracy (of about 78%) is achieved with support vector regression (SVR), closely followed by neural networks (NN). The simpler regression models that have been implemented are, however, not far behind. According to the SVR model, the average household is expected to lower their heating energy consumption by approximately 3% if the indoor temperature is decreased by 1°C. 

  • 294.
    Lindgren, Mattias
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Matematiska institutionen.
    Mobil kommunikation och högre tillgänglighet vid längre elavbrott: Exemplet stormen Dagmar och 4G-kommunikation inom smarta elnät2013Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    To be able to secure a safe and reliable power supply is becoming increasingly important since society depends on services and functions that need continuous power supply. The delivery rate in Swedish power supply is 99.98 % which insists on a high availability. During the past decade several storms has passed Sweden which resulted in large amount of tree felling leading to extended power outages. During these storms many socially critical activities, such as electric utility company Fortum, experienced disruption in mobile communication which affected the crisis management.

     

    This paper has investigated Swedish mobile operators’ crisis management at Hi3G, Tele2 and TeliaSonera with a case study of the storm Dagmar that hit Sweden during December in 2011. Furthermore this paper has investigated if 4G-communication (LTE) is appropriate to use in the next generation power grid, also known as smart grid. The study is based on literature studies and interviews with respondents from companies such as Hi3G, Tele2, TeliaSonera, Fortum and Ericsson.

     

    It has shown that the mobile operators have well developed crises management. The availability in mobile communication is dependent on power supply why it is critical to have backup power supply during extended power outages. Backup power supply varies between mobile operators. Interaction between mobile operators and electric utility companies during crisis should increase the availability in power grids and mobile communication.

     

    The LTE technology is well developed and could be used in smart grids to collect information. To use LTE for critical processes, such as controlling breakers, is not suitable with todays performance.

  • 295.
    Lindholm, Karin
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för systemteknik. IWR, Ruprecht-Karls-Universität Heidelberg, Germany.
    High Flying, Electrifying: Assessment and Extension of a Kite Model for Power Production2015Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    This thesis has its starting point in an existing computer model of an electricity generating kite, from Heidelberg University. The modelled kite has an area of 500 m2 and is tethered to a generator at sea. A control unit steers the kite in an optimised trajectory. The design and trajectory that maximise mean power output per loop had been found using the optimisation software MUSCOD-II.

    Firstly, the model is investigated in order to find possible adjustments to make it closer to reality. Then a method to take the economic aspect into account in the optimisation has been developed.

    The most important findings in the model survey concerned wind speed. The original model overrated the wind speed at high altitudes and it used a mean wind speed instead of including yearly variations. Adjustments are made and a new objective function aiming at maximising the yearly average power output per invested Euro is used.

    Furthermore, the revised model has a preset wind speed range within which the kite can operate, and a maximum power output of the generator (the nominal power) which is found through optimisation with respect of cost. Cable strength and other production limitations are included as well.

    Using cost estimations for relevant parts, the revised optimisation model results in a system with a tethering cable about half the original length, and a steadier power output over the loop. The yearly production sums up to 16.8 GWh, as compared to the original model which would have given 42.9 GWh yearly.

  • 296.
    Lindqvist, Daniel
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Strukturkemi.
    Simulation of Intermittent Current Interruption measurements on NMC-based lithium-ion batteries2017Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    The objective of this report was to implement battery cycling and an intermittent current interruption (ICI) method for determining battery resistance into a simple lithium-ion battery model in the finite element methods (FEM) program COMSOL Multiphysics, andevaluate how accurately the model reflects the behaviour of voltage and internal resistance with respect to experimental results. The ICI technique consists of repeating the steps of first having a longer charging period and then having a short current interruption, where the internal resistance is calculated from the voltage drop that occurs when the current is turned off. The model was evaluated against measurements, made with the same technique (ICI), on assembled NMC-graphite batteries. Codes written in the statistical programming language “R” were used to process the data from both COMSOL and the experiments. Both the batteries and the model were constructed with a reference electrode, to enable measurement of each electrode by itself.

    The results as documented in this report show that it is possible to simulate the measurement technique in COMSOL, but that both the resistance and voltage profiles differed quite a lot from the behaviour of the tested batteries. The resistance of the positive electrode did however give good results and it was possible to improve the model by changing some parameters. The magnitude of the resistance, which was already quite close, could be improved by changing the porosity and particle size, and the voltage profiles were improved when using voltage-data achieved from the real measurements.

  • 297.
    Lindroth [formerly Tyrberg], Simon
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Buoy and Generator Interaction with Ocean Waves: Studies of a Wave Energy Conversion System2011Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    On March 13th, 2006, the Division of Electricity at Uppsala University deployed its first wave energy converter, L1, in the ocean southwest of Lysekil. L1 consisted of a buoy at the surface, connected through a line to a linear generator on the seabed. Since the deployment, continuous investigations of how L1 works in the waves have been conducted, and several additional wave energy converters have been deployed.

    This thesis is based on ten publications, which focus on different aspects of the interaction between wave, buoy, and generator. In order to evaluate different measurement systems, the motion of the buoy was measured optically and using accelerometers, and compared to measurements of the motion of the movable part of the generator - the translator. These measurements were found to correlate well. Simulations of buoy and translator motion were found to match the measured values.

    The variation of performance of L1 with changing water levels, wave heights, and spectral shapes was also investigated. Performance is here defined as the ratio of absorbed power to incoming power. It was found that the performance decreases for large wave heights. This is in accordance with the theoretical predictions, since the area for which the stator and the translator overlap decreases for large translator motions. Shifting water levels were predicted to have the same effect, but this could not be seen as clearly.

    The width of the wave energy spectrum has been proposed by some as a factor that also affects the performance of a wave energy converter, for a set wave height and period. Therefore the relation between performance and several different parameters for spectral width was investigated. It was found that some of the parameters were in fact correlated to performance, but that the correlation was not very strong.

    As a background on ocean measurements in wave energy, a thorough literature review was conducted. It turns out that the Lysekil project is one of quite few projects that have published descriptions of on-site wave energy measurements.

    Delarbeid
    1. Wave Energy from the North Sea: Experiences from the Lysekil Research Site
    Åpne denne publikasjonen i ny fane eller vindu >>Wave Energy from the North Sea: Experiences from the Lysekil Research Site
    Vise andre…
    2008 (engelsk)Inngår i: Surveys in geophysics, ISSN 0169-3298, E-ISSN 1573-0956, Vol. 29, nr 3, s. 221-240Artikkel, forskningsoversikt (Fagfellevurdert) Published
    Abstract [en]

    This paper provides a status update on the development of the Swedish wave energy research area located close to Lysekil on the Swedish West coast. The Lysekil project is run by the Centre for Renewable Electric Energy Conversion at Uppsala University. The project was started in 2004 and currently has permission to run until the end of 2013. During this time period 10 grid-connected wave energy converters, 30 buoys for studies on environmental impact, and a surveillance tower for monitoring the interaction between waves and converters will be installed and studied. To date the research area holds one complete wave energy converter connected to a measuring station on shore via a sea cable, a Wave Rider™ buoy for wave measurements, 25 buoys for studies on environmental impact, and a surveillance tower. The wave energy converter is based on a linear synchronous generator which is placed on the sea bed and driven by a heaving point absorber at the ocean surface. The converter is directly driven, i.e. it has no gearbox or other mechanical or hydraulic conversion system. This results in a simple and robust mechanical system, but also in a somewhat more complicated electrical system.

    Emneord
    Wave power, Renewable energy, Sea trial, Linear generator, Point absorber, Environmental impact
    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-107215 (URN)10.1007/s10712-008-9047-x (DOI)000260967900002 ()
    Tilgjengelig fra: 2009-07-29 Laget: 2009-07-29 Sist oppdatert: 2017-12-13bibliografisk kontrollert
    2. The Lysekil Wave Power Project: Status Update
    Åpne denne publikasjonen i ny fane eller vindu >>The Lysekil Wave Power Project: Status Update
    Vise andre…
    2008 (engelsk)Konferansepaper, Publicerat paper (Fagfellevurdert)
    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-97846 (URN)
    Tilgjengelig fra: 2008-11-21 Laget: 2008-11-21 Sist oppdatert: 2014-04-29bibliografisk kontrollert
    3. Catch the wave to electricity: The Conversion of Wave Motions to Electricity Using a Grid-Oriented Approach
    Åpne denne publikasjonen i ny fane eller vindu >>Catch the wave to electricity: The Conversion of Wave Motions to Electricity Using a Grid-Oriented Approach
    Vise andre…
    2009 (engelsk)Inngår i: IEEE Power and Energy Magazine, ISSN 1540-7977, Vol. 7, nr 1, s. 50-54Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    The ocean are largely an untapped source of energy. However, compared to other energies, power fluctuations for ocean waves are small over longer periods of time. This paper present a grid-oriented approach to electricity production from ocean waves, utilizing a minimal amount of mechanical components.

    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-112949 (URN)10.1109/MPE.2008.930658 (DOI)000262015100004 ()
    Tilgjengelig fra: 2010-01-22 Laget: 2010-01-22 Sist oppdatert: 2017-01-25bibliografisk kontrollert
    4. Tracking a Wave Power Buoy Using a Network Camera: System Analysis and First Results
    Åpne denne publikasjonen i ny fane eller vindu >>Tracking a Wave Power Buoy Using a Network Camera: System Analysis and First Results
    2009 (engelsk)Inngår i: Volume 4: Ocean Engineering; Ocean Renewable Energy; Ocean Space Utilization, Parts A and B, Honolulu, Hawaii, 2009, s. 799-807Konferansepaper, Publicerat paper (Fagfellevurdert)
    Abstract [en]

    Anobservation system has been set up on a small isleton the Swedish west coast. The purpose of the systemis to monitor the wave buoys in The Lysekil Project.The project is an attempt to harvest wave energy usinglinear generators and point absorbing buoys. The observation system isself-sufficient and uses a network camera to follow the buoymotions. The first results from the camera, which has beenoperating since July 2008, have been analyzed to examine themotion tracking capabilities of the system. The motion tracking wouldwork as a complement to the other measurements that arebeing done on the buoy. The method for extracting motiondata from the two-dimensional pictures is presented. The results aregraphs of translative buoy motion in two dimensions, and rotationalmotion about two different axes. The vertical buoy motion forthe studied sequence is in the range of ±0.5 m.

    sted, utgiver, år, opplag, sider
    Honolulu, Hawaii: , 2009
    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-113302 (URN)10.1115/OMAE2009-79121 (DOI)
    Konferanse
    ASME 2009 28th International Conference on Ocean, Offshore and Arctic Engineering (OMAE2009) May 31–June 5, 2009 , Honolulu, Hawaii, USA
    Tilgjengelig fra: 2010-01-26 Laget: 2010-01-26 Sist oppdatert: 2014-04-29bibliografisk kontrollert
    5. Wave Power Absorption as a Function of Water Level and Wave Height: Theory and Experiment
    Åpne denne publikasjonen i ny fane eller vindu >>Wave Power Absorption as a Function of Water Level and Wave Height: Theory and Experiment
    2010 (engelsk)Inngår i: IEEE Journal of Oceanic Engineering, ISSN 0364-9059, E-ISSN 1558-1691, Vol. 35, nr 3, s. 558-564Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    This paper investigates the sensitivity of a wave power system to variations in still water levels and significant wave heights. The system consists of a floating point absorber connected to a linear generator on the seabed. Changing still water levels are expected to affect the power absorption, since they will displace the equilibrium position for the generator translator. Similarly, changing significant wave heights will affect the rate at which the translator leaves the stator. Both these effects will in some cases result in a smaller active area of the stator. A theoretical expression to describe this effect is derived, and compared to measured experimental values for the wave energy converter at the Lysekil research site. During the time of measurements, the still water levels at the site were in the range of [-0.70 m, +0.46 m], and the significant wave heights in the range of [0 m, 2.7 m]. The experimental values exhibit characteristics similar to those of the theoretical expression, especially with changing significant wave heights.

    Emneord
    Energy capture, experimental results, linear generator, power absorption, wave power
    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-97852 (URN)10.1109/JOE.2010.2052692 (DOI)000283226500008 ()
    Tilgjengelig fra: 2012-01-09 Laget: 2008-11-21 Sist oppdatert: 2017-12-14bibliografisk kontrollert
    6. Experimental Results From an Offshore Wave Energy Converter
    Åpne denne publikasjonen i ny fane eller vindu >>Experimental Results From an Offshore Wave Energy Converter
    Vise andre…
    2010 (engelsk)Inngår i: Journal of Offshore Mechanics and Arctic Engineering-Transactions of The Asme, ISSN 0892-7219, E-ISSN 1528-896X, Vol. 132, nr 4, s. 041103-Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    An offshore wave energy converter (WEC) was successfully launched at the Swedish west coast in the middle of March 2006. The WEC is based on a permanent magnet linear generator located on the sea floor driven by a point absorber. A measuring station has been installed on a nearby island where all measurements and experiments on the WEC have been carried out. The output voltage from the generator fluctuates both in amplitude and frequency and must therefore be converted to enable grid connection. In order to study the voltage conversion, the measuring station was fitted with a six pulse diode rectifier and a capacitive filter during the autumn of 2006. The object of this paper is to present a detailed description of the Lysekil research site. Special attention will be given to the power absorption by the generator when it is connected to a nonlinear load.

    Emneord
    ocean wave power, linear generators, conversion systems, experimental results
    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-133599 (URN)10.1115/1.4001443 (DOI)000283325300003 ()
    Tilgjengelig fra: 2010-11-15 Laget: 2010-11-11 Sist oppdatert: 2017-12-12bibliografisk kontrollert
    7. Wave Buoy and Translator Motions - On-Site Measurements and Simulations
    Åpne denne publikasjonen i ny fane eller vindu >>Wave Buoy and Translator Motions - On-Site Measurements and Simulations
    Vise andre…
    2011 (engelsk)Inngår i: IEEE Journal of Oceanic Engineering, ISSN 0364-9059, E-ISSN 1558-1691, Vol. 36, nr 3, s. 377-385Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    For a complete understanding of a wave energy conversion device, it is important to know how the proposed device moves in the water, how this motion can be measured, and to what extent the motion can be predicted or simulated. The magnitude and character of the motion has impacts on engineering issues and optimization of control parameters, as well as the theoretical understanding of the system. This paper presents real sea measurements of buoy motion and translator motion fora wave energy system using a linear generator. Buoy motion has been measured using two different systems: a land-based optical system and a buoy-based accelerometer system. The data have been compared to simulations from a Simulink model for the entire system. The two real sea measurements of buoy motion have been found to correlate well in the vertical direction, where the measured range of motion and the standard deviation of the position distributions differed with 3 and 4 cm, respectively. The difference in the horizontal direction ismore substantial. The main reason for this is that the buoy rotation about its axis of symmetry was not measured. However, used together the two systems give a good understanding of buoy motion. In a first comparison, the simulations show good agreement with the measured motion for both translator and buoy.

    Emneord
    Accelerometers, energy conversion, experimental results, image motion analysis, oceanic engineering, marine technology, wave power
    HSV kategori
    Forskningsprogram
    Teknisk fysik med inriktning mot elektricitetslära
    Identifikatorer
    urn:nbn:se:uu:diva-160072 (URN)10.1109/JOE.2011.2136970 (DOI)
    Tilgjengelig fra: 2012-01-09 Laget: 2011-10-14 Sist oppdatert: 2017-12-08bibliografisk kontrollert
    8. Lysekil Research Site, Sweden: A status update
    Åpne denne publikasjonen i ny fane eller vindu >>Lysekil Research Site, Sweden: A status update
    Vise andre…
    2011 (engelsk)Inngår i: 9th European Wave and Tidal Energy Conference, Southampton, UK, 2011, 2011Konferansepaper, Publicerat paper (Fagfellevurdert)
    HSV kategori
    Forskningsprogram
    Teknisk fysik med inriktning mot elektricitetslära
    Identifikatorer
    urn:nbn:se:uu:diva-160039 (URN)
    Konferanse
    9th European Wave and Tidal Energy Conference, Southampton, UK, 5-9 September 2011
    Tilgjengelig fra: 2011-10-13 Laget: 2011-10-13 Sist oppdatert: 2017-01-25
    9. Offshore wave power measurements: a review
    Åpne denne publikasjonen i ny fane eller vindu >>Offshore wave power measurements: a review
    2011 (engelsk)Inngår i: Renewable & sustainable energy reviews, ISSN 1364-0321, E-ISSN 1879-0690, Vol. 15, nr 9, s. 4274-4285Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    The first wave power patent was filed in 1799. Since then, hundreds of ideas for extraction of energy from ocean waves have surfaced. In the process of developing a concept, it is important to learn from previous successes and failures, and this is not least important when moving into the ocean. In this paper, a review has been made with the purpose of finding wave power projects that have made ocean trials, and that also have reported what has been measured during the trials, and how it has been measured.

    In relation to how many projects have done work on wave power, surprisingly few have reported on such measurements. There can be many reasons for this, but one is likely the great difficulties in working with experiments in an ocean environment. Many of the projects have reported on sensor failures, unforeseen events, and other general problems in making measurements at sea.

    The most common site measurement found in this review was wave height. Such measurements was almost universal, although the technologies used differed somewhat. The most common device measurements were electric voltages and/or currents and system pressures (air and water). Device motion and mooring forces were also commonly measured. The motion measurements differed the most between the projects, and many varying methods were used, such as accelerometers, wire sensors, GPS systems, optical systems and echo sounders.

    sted, utgiver, år, opplag, sider
    Elsevier, 2011
    Emneord
    Wave power, Measurement system, Offshore
    HSV kategori
    Forskningsprogram
    Teknisk fysik med inriktning mot elektricitetslära
    Identifikatorer
    urn:nbn:se:uu:diva-160081 (URN)10.1016/j.rser.2011.07.123 (DOI)000298764400006 ()
    Tilgjengelig fra: 2012-01-09 Laget: 2011-10-14 Sist oppdatert: 2017-12-08bibliografisk kontrollert
    10. Spectral Parameters and Wave Energy Converter Performance
    Åpne denne publikasjonen i ny fane eller vindu >>Spectral Parameters and Wave Energy Converter Performance
    (engelsk)Manuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    Wave energy converter performance is typically specified for given values of significant wave height Hm0 and energy period T-10, in a matrix. For such a representation to be valid, it must be assumed that two parameters determine the performance of the wave energy converter satisfactorily. However, studying performance data for the wave energy converter L1 at the Lysekil research site, it can be seen that for measurements with similar values of Hm0 and T-10, there are values of relative absorption that range from 5 % to 25 %. It therefore seems probable that the properties of the sea state that are not captured using Hm0 and T-10 have an effect on how a WEC performs. It has been proposed in the literature that the width of the wave spectrum is one such property. In this paper, six parameters that describe spectral width have been tested against performance data to look for correlations. In addition to this, the performance data was tested against peak period and standard deviation of peak frequency, as found through wavelet analysis. Out of the parameters tested, κ and ε1 displayed the strongest correlation with relative absorption. Even this correlation was not very strong however, and did only exhibit an r2-value of 0.39 in a linear fit for L1 connected to a 4.9 Ω load. It was also found that the lowest absorption values were connected to the lowest and highest values for peak period.

    HSV kategori
    Forskningsprogram
    Teknisk fysik med inriktning mot elektricitetslära
    Identifikatorer
    urn:nbn:se:uu:diva-160084 (URN)
    Tilgjengelig fra: 2011-10-14 Laget: 2011-10-14 Sist oppdatert: 2012-01-04
  • 298.
    Lingfors, David
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Illumination properties and energy savings of a solar fiber optic lighting system balanced by artificial lights2013Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    A solar fiber optic lighting system, SP3 from the Swedish company Parans Solar Lighting AB, has been installed in a study area/corridor test site. A collector is tracking the sun during daytime, focusing the direct sun irradiance via Fresnel lenses into optical fibers, which guide the solar light into the building. The illumination properties of the system have been characterized. The energy saving due to reduced need of artificial lighting have been calculated and methods for balancing the artificial lights in the test site have been evaluated.

    The illumination at the test site using solar light was at least as high as when using the artificial lights and even higher at very clear days. The luminous flux output (500 lm) was somewhat lower than specified by the manufacturer (550 lm) at 100 000 lx direct sun illuminance. The output at 130 000 lx was high 767±33 lm the sunlight coupling efficiency 23 %. However, for a 20 m SP3 system the luminous flux output (400 lm) at 100 000 lx was higher than specified (350 lm).

    The SP3 system of Parans provides high quality solar light. It has a fuller spectrum close to the spectrum of the sun compared to the fluorescent lights at the test site. The correlated color temperature of the system was 5800±300 K and the color rendering index 84.9±0.5.

    The lighting energy saved due to decreased need for artificial light was estimated to 19 % in Uppsala which has 1790 annual sun hours. The savings in Italy, which has 3400 sun hours, is 46 %. Additional saving, especially in warmer countries can be obtained due to decreased need for cooling in the building as the solar luminaires provide negligible heat to the indoor air. Economical saving could also be realized by improved well-being of the occupants spending time under the solar luminaires.

    Three ways of balancing the artificial light due to sunshine fluctuations have been investigated. The global horizontal irradiance could not be used as a control signal for balancing the artificial lights but a pyranometer attached to the SP3 sun tracking collector was usable. Also the signal from an indoor luxmeter sensor could be used for balancing the light. However the signal from the light sensor which makes the SP3 collector to track the sun is probably the most cost effective method as it would serve two purposes; tracking the sun and balancing the artificial lights.

  • 299.
    Lingfors, David
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Solar Variability Assessment and Grid Integration: Methodology Development and Case Studies2015Licentiatavhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    During the 21st century there has been a tremendous increase in grid-connected photovoltaic (PV) capacity globally, due to falling prices and introduction of economic incentives. PV systems are in most cases small-scale, installed on residential dwellings, which means that the power production is widely distributed and close to the end-user of electricity. In this licentiate thesis the distributed PV in the built environment is studied. A methodology for assessing short-term (sub-minute) solar variability was developed, which in the continuation of this PhD project could be used to study the aggregated impact on the local distribution grid from dispersed PV systems. In order to identify potential locations for PV systems in a future scenario, methodology was developed to assess the rooftop topography on both local level using LiDAR data and nationally through building statistics. Impacts on the distribution grid were investigated through a case study on a rural municipality in Sweden. It was found that the hosting capacity, i.e. the amount of PV power generation that can be integrated in the grid without exceeding certain power quality measures, is high, at least 30%. However, the hosting capacity on transmission level needs further investigation. As a first step a methodology was developed in order to model scenarios for hourly solar power generation, aggregated over wide areas, here applied to the whole Swedish power system. The model showed high correlation compared to PV power production reported to the Swedish transmission system operator (TSO). Furthermore, it was used to model scenarios of high PV penetration in Sweden, which give some indications on the impact on the power system, in terms of higher frequency of extreme ramps.

    Delarbeid
    1. Variability Assessment and Forecasting of Renewables: A Review for Solar, Wind, Wave and Tidal Resources
    Åpne denne publikasjonen i ny fane eller vindu >>Variability Assessment and Forecasting of Renewables: A Review for Solar, Wind, Wave and Tidal Resources
    Vise andre…
    2015 (engelsk)Inngår i: Renewable & sustainable energy reviews, ISSN 1364-0321, E-ISSN 1879-0690, Vol. 44, s. 356-375Artikkel i tidsskrift (Fagfellevurdert) Published
    HSV kategori
    Forskningsprogram
    Teknisk fysik med inriktning mot elektricitetslära; Teknisk fysik med inriktning mot fasta tillståndets fysik
    Identifikatorer
    urn:nbn:se:uu:diva-225870 (URN)10.1016/j.rser.2014.12.019 (DOI)000351324300025 ()
    Tilgjengelig fra: 2014-06-09 Laget: 2014-06-09 Sist oppdatert: 2018-08-01
    2. Characteristics of a low-cost solar irradiance logger
    Åpne denne publikasjonen i ny fane eller vindu >>Characteristics of a low-cost solar irradiance logger
    (engelsk)Manuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    Since photovoltaic (PV) power is highly intermittent the impact on the power system has been studied more thoroughly the last few years. However, there is a lack of high resolution data needed for solar variability studies, which demand dense solar irradiance monitoring networks. Here we present a silicon cell based data logger gathering global irradiance data with sampling intervals down to one second. In all it costs around \euro 40, making it significantly cheaper than commercial products, but also cheaper compared to similar dataloggers. It has a root-mean-square error (RMSE) of 16 W/m$^2$ compared to a commercial thermopile pyranometer. Since the solar logger is intended to be used in solar variability studies,the RMSE of the clear sky index step change was studied and was shown to be 0.014 averaged over 5 minutes, and 0.029 averaged over 10 seconds. The low cost yet high accuracy of the logger, combined with its high mobility and and low power consumption makes it a viable choice when designing a monitoring network for solar variability studies or in other solar energy related projects, e.g. in developing countries, where low-cost is important.

    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-265448 (URN)
    Tilgjengelig fra: 2015-10-29 Laget: 2015-10-29 Sist oppdatert: 2018-02-20
    3. Determining Intra-hour Solar Irradiance Variability with a Low-cost Solar Logger Network
    Åpne denne publikasjonen i ny fane eller vindu >>Determining Intra-hour Solar Irradiance Variability with a Low-cost Solar Logger Network
    2014 (engelsk)Inngår i: Proceedings of 4th International Workshop on Integration of Solar Power into Power Systems, Berlin, Germany, 10-11 November, 2014, 2014Konferansepaper, Publicerat paper (Annet vitenskapelig)
    Abstract [en]

    The study of solar irradiance is of vital importance in order to quantify the fluctuation that the transmission system needs to handle in case of large scale solar power integration. In this paper, early results from a low-cost solar irradiance logger network are presented. The main advantages of the solar logger are its low cost (~$50) and mobility. Our results confirm previous models of the station pair correlation of clear sky index step changes, with the modification that the isotropic correlation appears to decrease exponentially as a function of Δt-1/2 rather than Δt-1 as has been proposed earlier.

    HSV kategori
    Forskningsprogram
    Teknisk fysik
    Identifikatorer
    urn:nbn:se:uu:diva-239146 (URN)9783981654905 (ISBN)
    Konferanse
    4th International Workshop on Integration of Solar Power into Power Systems, Berlin, Germany, 10-11 November, 2014
    Tilgjengelig fra: 2014-12-18 Laget: 2014-12-18 Sist oppdatert: 2018-02-20
    4. Development and validation of a wide-area model of hourly aggregate solar power generation
    Åpne denne publikasjonen i ny fane eller vindu >>Development and validation of a wide-area model of hourly aggregate solar power generation
    2016 (engelsk)Inngår i: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 102, s. 559-566Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    The impact of photovoltaics (PV) on the power system becomes increasingly important to study as the penetration of PV has increased rapidly over the last decade. A physical model for aggregated PV generation has been developed for the Swedish spot market areas. Information about PV systems within the Swedish electricity certificate system and irradiance data from the meteorological model STRÅNG were used as inputs. The model was trained and validated against production data reported to the Swedish transmission system operator. Our model shows high correlation (0.95-0.99) to reported historical production data. However, it overestimates extreme 1h ramp rates, which are -20% and 22% for down- and up-ramps respectively, compared to -13% and 14% for the reported data. Furthermore a weighting function was developed, which takes demography, available solar irradiance and today's PV deployment into account, to model likely deployment in a Swedish high penetration scenario, where PV covers 6% of the total annual power demand. The difference in extreme 1 and 4 hour step changes before and after introducing PV is small. The model could thus be used with confidence to model the impact on the power system for future scenarios of high PV penetration.

    Emneord
    PV power; Step changes; Solar variability; Physical model
    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-265450 (URN)10.1016/j.energy.2016.02.085 (DOI)000375889400050 ()
    Forskningsfinansiär
    StandUp
    Tilgjengelig fra: 2015-10-29 Laget: 2015-10-29 Sist oppdatert: 2018-02-20bibliografisk kontrollert
    5. Self-consumption enhancement of residential photovoltaics with battery storage and electric vehicles in communities
    Åpne denne publikasjonen i ny fane eller vindu >>Self-consumption enhancement of residential photovoltaics with battery storage and electric vehicles in communities
    2015 (engelsk)Inngår i: Proceedings of the eceee 2015 Summer Study on energy efficiency, 1–6 June 2015, Presqu’île de Giens, Toulon/Hyères, France, 2015, s. 991-1002Konferansepaper, Publicerat paper (Fagfellevurdert)
    Abstract [en]

    Grid-connected photovoltaic (PV) systems have been dependent on supporting schemes to be competitive with conventional electricity generation. Selling prices of PV power production are now lower than buying prices in several countries, making it profitable to match generation with household consumption. Self-consumption, calculated as in situ instantaneous consumption of PV power production relative to total power production, can be used to improve the profitability with higher buying than selling prices of electricity. Another measure, self-sufficiency, similar to self-consumption but calculated relative to the yearly consumption, can also be used. Battery storage and electric vehicle (EV) home-charging are interesting alternatives to increase the self-consumption, since the PV power production can be stored for later use. This study uses high-resolution consumption data for 21 single-family houses in Sweden and irradiance data for the year 2008 to examine the potential for battery storage and EV home-charging for communities of single-family houses with PV systems. The aim is to compare how self-consumption and self-sufficiency are affected by individual power grid connections for all households versus one shared grid connection for the whole community. These scenarios are combined with battery storage and EV charging (individual versus centralized). It is found that total consumption profiles level out when several houses are connected together, the self-consumption increases from 52 to 71 % and the self-sufficiency from 12 to 17 %. The size of a centralized storage can be reduced compared to the aggregated size of storages in every house to reach the same level of self-consumption. The potential for EV charging is limited due to mismatch between irradiance and charging patterns. The extra revenue from increased self-consumption with battery storage is too low for all the cases to justify an investment in batteries since the prices are still too high. With dedicated support schemes, higher buying prices of electricity and cheaper battery, PV-battery systems can still be an interesting solution in countries with high solar irradiance throughout the year.

    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-254455 (URN)978-91-980482-6-1 (ISBN)
    Konferanse
    eceee 2015 Summer Study on energy efficiency, 1–6 June 2015, Presqu’île de Giens, Toulon/Hyères, France
    Prosjekter
    Småskalig solel i byggnader - kraft för förändring i energisystem och vardagslivet
    Forskningsfinansiär
    Swedish Energy Agency
    Tilgjengelig fra: 2015-06-08 Laget: 2015-06-08 Sist oppdatert: 2018-02-20
    6. Maximizing PV hosting capacity by smart allocation of PV: A case study on a Swedish distribution grid
    Åpne denne publikasjonen i ny fane eller vindu >>Maximizing PV hosting capacity by smart allocation of PV: A case study on a Swedish distribution grid
    2015 (engelsk)Inngår i: Proceedings of ASES Solar 2015, Pennsylvania State University, Pennsylvania, USA, July 28-30, 2015, 2015Konferansepaper, Publicerat paper (Annet vitenskapelig)
    Abstract [en]

    Detailed simulations of large amounts of PV production in Swedish rural power grids show that as module and system prices keep declining and thus increasing the profitability and demand for solar power, current grid performance will limit the potential. Simulations have been made on a case distribution grid (10 kV) with actual hourly load data for 2014 and calculated hourly production with respect to building roof area, tilt and azimuth together with irradiation data. At high production, especially voltage rises along cables in the outer part of the grid is problematic, but also currents in cables close to transformer buses increases substantially at these conditions. Resulting hosting capacity for the case grid is 32%, as of annual production compared to annual demand. What is limiting the hosting capacity is the tolerated voltage rise, which is set to 5% of nominal grid voltage. Through smart allocation of PV systems to the strongest nodes in the grid the hosting capacity of the same grid can be increased to 74%.

    HSV kategori
    Forskningsprogram
    Teknisk fysik
    Identifikatorer
    urn:nbn:se:uu:diva-265444 (URN)
    Konferanse
    ASES Solar 2015, Pennsylvania State University, Pennsylvania, USA, July 28-30, 2015
    Tilgjengelig fra: 2015-10-29 Laget: 2015-10-29 Sist oppdatert: 2018-02-20
  • 300.
    Lingfors, David
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Solar Variability Assessment in the Built Environment: Model Development and Application to Grid Integration2017Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    During the 21st century there has been a rapid increase in grid-connected photovoltaic (PV) capacity globally, due to falling system component prices and introduction of various economic incentives. To a large extent, PV systems are installed on buildings, which means they are widely distributed and located close to the power consumer, in contrast to conventional power plants. The intermittency of solar irradiance poses challenges to the integration of PV, which may be mitigated if properly assessing the solar resource. In this thesis, methods have been developed for solar variability and resource assessment in the built environment on both national and local level, and have been applied to grid integration studies. On national level, a method based on building statistics was developed that reproduces the hourly PV power generation in Sweden with high accuracy; correlation between simulated and real power generation for 2012 and 2013 were 0.97 and 0.99, respectively. The model was applied in scenarios of high penetration of intermittent renewable energy (IRE) in the Nordic synchronous power system, in combination with similar models for wind, wave and tidal power. A mix of the IRE resources was sought to minimise the variability in net load (i.e., load minus IRE, nuclear and thermal power). The study showed that a fully renewable Nordic power system is possible if hydropower operation is properly planned for. However, the contribution from PV power would only be 2-3% of the total power demand, due to strong diurnal and seasonal variability. On local level, a model-driven solar resource assessment method was developed based on low-resolution LiDAR (Light Detection and Ranging) data. It was shown to improve the representation of buildings, i.e., roof shape, tilt and azimuth, over raster-based methods, i.e., digital surface models (DSM), which use the same LiDAR data. Furthermore, the new method can provide time-resolved data in contrast to traditional solar maps, and can thus be used as a powerful tool when studying the integration of high penetrations of PV in the distribution grid. In conclusion, the developed methods fill important gaps in our ability to plan for a fully renewable power system.

    Delarbeid
    1. Variability Assessment and Forecasting of Renewables: A Review for Solar, Wind, Wave and Tidal Resources
    Åpne denne publikasjonen i ny fane eller vindu >>Variability Assessment and Forecasting of Renewables: A Review for Solar, Wind, Wave and Tidal Resources
    Vise andre…
    2015 (engelsk)Inngår i: Renewable & sustainable energy reviews, ISSN 1364-0321, E-ISSN 1879-0690, Vol. 44, s. 356-375Artikkel i tidsskrift (Fagfellevurdert) Published
    HSV kategori
    Forskningsprogram
    Teknisk fysik med inriktning mot elektricitetslära; Teknisk fysik med inriktning mot fasta tillståndets fysik
    Identifikatorer
    urn:nbn:se:uu:diva-225870 (URN)10.1016/j.rser.2014.12.019 (DOI)000351324300025 ()
    Tilgjengelig fra: 2014-06-09 Laget: 2014-06-09 Sist oppdatert: 2018-08-01
    2. Development and validation of a wide-area model of hourly aggregate solar power generation
    Åpne denne publikasjonen i ny fane eller vindu >>Development and validation of a wide-area model of hourly aggregate solar power generation
    2016 (engelsk)Inngår i: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 102, s. 559-566Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    The impact of photovoltaics (PV) on the power system becomes increasingly important to study as the penetration of PV has increased rapidly over the last decade. A physical model for aggregated PV generation has been developed for the Swedish spot market areas. Information about PV systems within the Swedish electricity certificate system and irradiance data from the meteorological model STRÅNG were used as inputs. The model was trained and validated against production data reported to the Swedish transmission system operator. Our model shows high correlation (0.95-0.99) to reported historical production data. However, it overestimates extreme 1h ramp rates, which are -20% and 22% for down- and up-ramps respectively, compared to -13% and 14% for the reported data. Furthermore a weighting function was developed, which takes demography, available solar irradiance and today's PV deployment into account, to model likely deployment in a Swedish high penetration scenario, where PV covers 6% of the total annual power demand. The difference in extreme 1 and 4 hour step changes before and after introducing PV is small. The model could thus be used with confidence to model the impact on the power system for future scenarios of high PV penetration.

    Emneord
    PV power; Step changes; Solar variability; Physical model
    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-265450 (URN)10.1016/j.energy.2016.02.085 (DOI)000375889400050 ()
    Forskningsfinansiär
    StandUp
    Tilgjengelig fra: 2015-10-29 Laget: 2015-10-29 Sist oppdatert: 2018-02-20bibliografisk kontrollert
    3. Net load variability in Nordic countries with a highly or fully renewable power system
    Åpne denne publikasjonen i ny fane eller vindu >>Net load variability in Nordic countries with a highly or fully renewable power system
    Vise andre…
    2016 (engelsk)Inngår i: Nature Energy, ISSN 2058-7546, Vol. 1, s. 1-8, artikkel-id 16175Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Increasing the share of intermittent renewable energy (IRE) resources such as solar, wind, wave and tidal energy in a power system poses a challenge in terms of increased net load variability. Fully renewable power systems have previously been analysed, but more systematic analyses are needed that explore the effect of different IRE mixes on system-wide variability across different timescales and the optimal combinations of IRE for reducing variability on a given timescale. Here we investigate these questions for the Nordic power system. We show that the optimal mix of IRE is dependent on the frequency band considered. Long-term (>4 months) and short-term (<2 days) fluctuations can be similar to today’s, even for a fully renewable system. However, fluctuations with periods in between will inevitably increase significantly. This study indicates that, from a variability point of view, a fossil- and nuclear-free Nordic power system is feasible if properly balanced by hydropower.

    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-302836 (URN)10.1038/NENERGY.2016.175 (DOI)000394793000001 ()
    Forskningsfinansiär
    StandUpStandUp for Wind
    Tilgjengelig fra: 2016-09-11 Laget: 2016-09-11 Sist oppdatert: 2019-04-05
    4. Comparing the capability of low- and high-resolution LiDAR data with application to solar resource assessment, roof type classification and shading analysis
    Åpne denne publikasjonen i ny fane eller vindu >>Comparing the capability of low- and high-resolution LiDAR data with application to solar resource assessment, roof type classification and shading analysis
    Vise andre…
    2017 (engelsk)Inngår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 205, s. 1216-1230Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    LiDAR (Light Detection and Ranging) data have recently gained popularity for use in solar resource assessment and solar photovoltaics (PV) suitability studies in the built environment due to robustness at identifying building orientation, roof tilt and shading. There is a disparity in the geographic coverage of low- and high-resolution LiDAR data (LL and LH, respectively) between rural and urban locations, as the cost of the latter is often not justified for rural areas where high PV penetrations often pose the greatest impact on the electricity distribution network. There is a need for a comparison of the different resolutions to assess capability of LL. In this study, we evaluated and improved upon a previously reported methodology that derives roof types from a LiDAR-derived, low-resolution Digital Surface Model (DSM) with a co-classing routine. Key improvements to the methodology include: co-classing routine adapted for raw LiDAR data, applicability to differing building type distribution in study area, building height and symmetry considerations, a vector-based shading analysis of building surfaces and the addition of solar resource assessment capability.

    Based on the performance of different LiDAR resolutions within the developed model, a comparison between LL (0.5-1 pts/m(2)) and LH (6-8 pts/m(2)) LiDAR data was applied; LH can confidently be used to evaluate the applicability of LL, due to its significantly higher point density and therefore accuracy. We find that the co-classing methodology works satisfactory for LL for all types of building distributions. Roof-type identification errors from incorrect co-classing were rare (< 1%) with LL. Co-classing buildings using LL improves accuracy of roof-type identification in areas with homogeneous distribution of buildings, here from 78% to 86% in accuracy. Contrastingly, co-classing accuracy using LH is marginally reduced for all building distributions from 94.8% to 94.4%. We adapt the Hay and Davies solar transposition model to include shading. The shading analysis demonstrates similarity of results between LL and LH. We find that the proposed methodology can confidently be used for solar resource assessments on buildings when only LiDAR data of low-resolution (< 1 pts/m(2)) is available.

    sted, utgiver, år, opplag, sider
    Elsevier, 2017
    Emneord
    LiDAR, Solar resource assessment, Shading, Building classification, Low-resolution, High-resolution
    HSV kategori
    Forskningsprogram
    Teknisk fysik
    Identifikatorer
    urn:nbn:se:uu:diva-332226 (URN)10.1016/j.apenergy.2017.08.045 (DOI)000414817100098 ()
    Tilgjengelig fra: 2017-10-25 Laget: 2017-10-25 Sist oppdatert: 2018-02-20bibliografisk kontrollert
    5. Identification of PV system shading using a LiDAR-based solar resource assessment model: an evaluation and cross-validation
    Åpne denne publikasjonen i ny fane eller vindu >>Identification of PV system shading using a LiDAR-based solar resource assessment model: an evaluation and cross-validation
    Vise andre…
    2018 (engelsk)Inngår i: Solar Energy, ISSN 0038-092X, E-ISSN 1471-1257, Vol. 159, s. 157-172Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Photovoltaic (PV) systems are subject to several different systematic de-rating factors, such as soiling, degradation, inverter mismatch and shading. With increasing penetration of PV in the local grid, Distribution Network Service Providers (DNSPs) are inclined to assess such losses, in order to accurately estimate the total regional power output of distributed PV. The most influential de-rating factor is shading, which can cause ramps on the generated power output, similar to clouds. In this study we evaluate and compare two fundamentally different methods for module orientation parametrisation and shading analysis of PV systems that have been developed in previous work. In the first method, LiDAR (Light Detection and Ranging) data are used to derive the PV module orientation and shading, referred to herein as LiDAR model. The second method, referred to as the QCPV-Tuning model, is based on reported PV power generation, which is firstly quality controlled and parametrised in order to derive module orientation and a loss factor, LF, representing systematic de-rating factors. Secondly, variations in de-ratings throughout the day, mainly due to shading, are explored in a process referred to as Tuning. For both methods, binary time series are derived expressing the presence of shading, which are used to evaluate how the methods corroborate. We evaluate four cases; case 1) evaluates the original versions of the LiDAR and QCPV-Tuning models, while in case 2-4 improvements to the models are introduced. A new filter for extracting representative LiDAR data points for the shading analysis was introduced for the LiDAR model (case 2). For the QCPV-Tuning model significant inaccuracies in the parametrisation of the module orientation were identified due to strong shading in either morning or evening and were thus corrected to observed parameters (case 3). For case 4) improvements on both models were introduced. The Pearson correlation coefficients of shading events for the methods were 0.28, 0.36, 0.42 and 0.50 for case 1-4, respectively. A mismatch in the timing of shading events motivated the comparison of the mean hourly shading, with correlation coefficients of 0.34, 0.43, 0.49 and 0.57 for case 1-4, respectively. The results of this study show that both methods can confidently be used for solar resource assessment, given the suggested improvements.

    sted, utgiver, år, opplag, sider
    Elsevier, 2018
    Emneord
    Solar resource assessment, Shading, PV Tuning, LiDAR
    HSV kategori
    Forskningsprogram
    Teknisk fysik
    Identifikatorer
    urn:nbn:se:uu:diva-332235 (URN)10.1016/j.solener.2017.10.061 (DOI)000423007300016 ()
    Tilgjengelig fra: 2017-10-25 Laget: 2017-10-25 Sist oppdatert: 2018-03-12bibliografisk kontrollert
    6. Self-consumption enhancement and peak shaving of residential photovoltaics using storage and curtailment
    Åpne denne publikasjonen i ny fane eller vindu >>Self-consumption enhancement and peak shaving of residential photovoltaics using storage and curtailment
    2016 (engelsk)Inngår i: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 112, s. 221-231Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Increasing the self-consumption of photovoltaic (PV) power is an important aspect to integrate more PV power in the power system. The profit for the PV system owner can increase and the stress on the power grid can be reduced. Previous research in the field has focused on either self-consumption of PV power in individual buildings or PV power curtailment for voltage control. In this paper self-consumption of residential PV power in a community of several single-family houses was investigated using high-resolution irradiance and power consumption data. Cases with individual or shared battery energy storages for the houses were examined. PV power curtailment was investigated as a method to reduce feed-in power to the grid, i.e. peak shaving. Results indicated that the self-consumption ratio increased when using shared instead of individual storage. Reducing the feed-in power from the community by almost 50% only led to maximum 7% yearly production losses due to curtailment and storage losses. The economics for shared storage are slightly better than for individual ones. These results suggest that residential PV-battery systems should use (i) shared energy storage options if local regulations allow it and (ii) PV power curtailment if there are incentives to lower the feed-in power.

    sted, utgiver, år, opplag, sider
    Elsevier, 2016
    Emneord
    Photovoltaics, Solar energy, Self-consumption, Energy storage, Battery, Curtailment
    HSV kategori
    Forskningsprogram
    Teknisk fysik med inriktning mot fasta tillståndets fysik
    Identifikatorer
    urn:nbn:se:uu:diva-283612 (URN)10.1016/j.energy.2016.06.039 (DOI)000385318700021 ()
    Prosjekter
    Småskalig solel i byggnader – kraft för förändring i energisystem och vardaglivet
    Forskningsfinansiär
    Swedish Energy Agency, P37511-1
    Tilgjengelig fra: 2016-04-13 Laget: 2016-04-13 Sist oppdatert: 2018-10-10bibliografisk kontrollert
    7. Large-scale integration of photovoltaic power in a distribution grid using power curtailment and energy storage
    Åpne denne publikasjonen i ny fane eller vindu >>Large-scale integration of photovoltaic power in a distribution grid using power curtailment and energy storage
    2017 (engelsk)Inngår i: Solar Energy, ISSN 0038-092X, E-ISSN 1471-1257, Vol. 155, s. 1319-1325Artikkel i tidsskrift (Fagfellevurdert) Published
    Emneord
    Photovoltaics, Power distribution system, Energy storage, Power and voltage control, Overvoltage
    HSV kategori
    Forskningsprogram
    Teknisk fysik
    Identifikatorer
    urn:nbn:se:uu:diva-328066 (URN)10.1016/j.solener.2017.07.083 (DOI)000414819900057 ()
    Prosjekter
    Småskalig solel i byggnader – kraft för förändring i energisystem och vardaglivetUtvärdering av tekniska lösningar för att hantera omfattande anslutning av solcellssystem i eldistributionsnät
    Forskningsfinansiär
    Swedish Energy Agency, P37511-1
    Merknad

    Photovoltaic (PV) power generation is an important component for the future energy system. High penetrationof PV power in a power distribution system might however lead to problems with overvoltage and overload. In this study, a method for PV power curtailment and placement of decentralized energy storage is developed to control voltage, feeder currents and distribution substation overloading. The method determines an individual feed-in power limit for each PV system owner based on a voltage-power relationship. Measured data from a 10 kV/400 V three-phase distribution grid in the Swedish municipality of Herrljunga with more than 5000 end-users and simulated PV electricity production data are used for a case study to verify the model. The method is evaluated for yearly PV electricity productionof up to 100% of the yearly electricity consumption. The results show that the method is able to prevent overvoltage for all penetration levels in the studied distribution grid, reduce the number of feeders affected by overcurrent and lower the maximum load on the two substations.

    Tilgjengelig fra: 2017-08-16 Laget: 2017-08-16 Sist oppdatert: 2018-10-10bibliografisk kontrollert
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