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  • 1.
    Abuzohri, Ahmed
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Industrial Engineering & Management.
    Business Development: Market research & feasibility study of a PV-wind hybrid system for commercial use2018Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The definition of environmental sustainability has emerged strongly in the past decades. Industrial organizations worldwide have gone through a number of changes to take their social responsibilities and maintain sustainability by, among other things, replacing the conventional energy-based applications by renewable energy-based solutions. A so-called hybrid power system for electrification, consisting of wind turbines and solar panels, was developed by Vertical Wind AB to be installed on rooftops of residential buildings. The present thesis project analyzed the willingness of the large real estate companies in Uppsala region to adopt the new concept for electrification and conducted a market research on the new developed wind turbines, by Vertical Wind AB, in addition to solar- and wind resources in the target locations. It turned out that the willingness of having such a power system for electrification was high but not extremely high as expected and the hybrid power system was perceived as any other product or investment on the market where profitability is the vital decision parameter while the environmental aspect was slightly considered.

  • 2.
    Ahmad, Haseeb
    Gotland University, School of Culture, Energy and Environment.
    Offshore Wind Park Connection to an HVDC Platform, without using an AC Collector Platform2012Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This thesis investigates the comparison between two different alternating current topologies of an offshore wind farms connection to an offshore high voltage direct current (HVDC) converter platform. The offshore high voltage direct current converter platform converts alternating current into direct current. Two different topologies will be investigated.

    In the first topology, the offshore wind farms are connected to an HVDC converter platform through offshore AC collector platform. An offshore AC collector platform is used to collect energy from the wind farm and step up the voltages for transmission to HVDC convertor platform. The offshore AC collector platforms contribute significantly in the total cost and technical complexity of the HVDC connection.

    In the second topology, the offshore AC collector platform is removed from the circuit and the offshore wind farms are connected directly to offshore HVDC converter platform.

    In this thesis, short circuit analysis and loss analysis of an offshore wind farm cluster connected to an offshore HVDC converter platform is conducted for the two topologies described above.

    Two wind turbine generator types i.e. doubly fed induction generator and full conversion generator is compared for two different topologies. The effect of changing the distance between wind farms and offshore HVDC converter platform on short circuit currents in the absence of AC collector platform is presented for the second configuration. Two internal voltage levels i.e. 33 kV and 66kV of wind farms are compared for short circuit currents in the absence of AC collector platform. DIgSILENT software is used to perform short circuit calculations.

    The thesis is done in collaboration with “Offshore Wind Connections” department ABB, Sweden. The idea is still under development however this study will serve as good starting point to figure out the cost efficient AC topology of an offshore wind park HVDC connection.

  • 3.
    Alavanja, Bojan
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Application of SCADA Data Monitoring Methodology and Reliability Analysis of Wind Farm Operational Data2016Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Reliability of wind turbine components and maintenance optimisation are among the critical aspects of wind power development closely related to profitability and future development. The main reason for research in these areas is lowering the cost of energy production for wind power, specifically important in offshore environment. Continuous monitoring of specific wind turbine components can be valuable for wind farm operators and, subsequently, wind farm owners.  Also, health assessment of critical components can be useful in estimating the possibilities for life extension of wind turbines. Expensive Condition Monitoring Systems (CMSs) are not always available, particularly in older wind farms, and additionally installing CMSs on wind turbines is not always economically feasible. However, most of modern wind turbines are equipped with the Supervisory Control And Data Acquisition (SCADA) system which is recording 10-minute average values of parameters that depict operation of the turbine. That being said, SCADA data contains a vast amount of information that can be used for analysis of wind turbine components health. Therefore, this project will present an application of previously published methodology for SCADA data condition monitoring on real wind farm data. The goal of this project is to investigate on the possibilities of the SCADA monitoring methodology and what can be the added value of the application for wind farm operators, owners and other stakeholders.

    The methodology for condition monitoring through SCADA data was applied on real data gathered from two wind farms in Germany and one in the Netherlands. During the project the methodology had to be modified in order to ensure the best possible industrial application. Results of the project showed that the SCADA data condition monitoring approach is not capable of predicting failures. However, the technique has been proven successful for detecting the changes of trends in dependencies of working parameters, specifically monitoring parameters related to the turbine generators. Continuously monitoring the dependencies of working parameters can be used as an additional source of information for maintenance scheduling and assessment of components health. The approach presented in this paper can be valuable to asset managers and wind farm owners.

  • 4.
    Antans, Andis
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Multi-Criteria Decision Analysis in Wind power Project Development: Case study in Latvia2017Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Wind Power Project Development is a complicated, capital and resource-inclusive process, where a wide variety of factors have to be considered and several stakeholders have a significant say in the process. Decision making in such an environment is complex and has to be approached comprehensively. In order to sustain a structured and clear decision-making process, the sustainable energy industry has recognized Multi-Criteria Decision Analysis (MCDA) method as a suitable set of tools to aid in the decision-making process. One of the MCDA tools – PROMETHEE II, has been examined in this master thesis, to evaluate its eligibility as a decision making aid in wind power project development.

    To structurally and realistically evaluate the tool, it has been applied to a case study in Ventspils region, in Latvia. The author of this thesis has a preliminary agreement with the owners of the sites to develop the project, therefore, this thesis has a strong potential for a practical implementation in future. Four scenarios have been developed for an evaluation, contributing to four variations of the different amount of turbines erected, with two different hub heights, on two differently sized sites. The scenarios are assessed based on the interests of six key stakeholders. Their opinion on twelve criteria is examined.

    Input data for each criterion has been generated via WindPro and MS Excel software or by authors assessment based on the researched literature. PROMETHEE II is used to extrapolate a comprehensive and clear representation of the results.

    The evaluation of the MCDA method proved that MCDA tools, and PROMETHEE II, in particular, can provide excellent support in decision making in wind power development. A wide variety of input data, as well as the various and often contradicting interests by different stakeholders, can be taken into account, while, at the same time, a clear result that can assist in decision making, is generated. 

    Wind Power Project Development is a complicated, capital and resource-inclusiveprocess, where a wide variety of factors have to be considered and severalstakeholders have a significant say in the process. Decision making in such anenvironment is complex and has to be approached comprehensively. In order to sustaina structured and clear decision making process, sustainable energy industry hasrecognized Multi-Criteria Decision Analysis (MCDA) method as a suitable set of tools toaid in the decision making process. One of the MCDA tools – PROMETHEE II, hasbeen examined in this master thesis, to evaluate its eligibility as a decision making aidin wind power project development.To structurally and realistically evaluate the tool, it has been applied on a case study inVentspils region, in Latvia. The author of this thesis has a preliminary agreement withthe owners of the sites to develop the project, therefore, this thesis has a strongpotential for a practical implementation in future. Four scenarios have been developedfor an evaluation, contributing to four variations of different amount of turbines erected, with two different hub heights, on two differently sized sites. The scenarios are assessed based on the interests of six key stakeholders. Their opinion on twelve criteria examined. Input data for each criterion has been generated via WindPro and MS Excel software orby authors assessment based on the researched literature. PROMETHEE II is used to extrapolate a comprehensive and clear representation of the results.The evaluation of the MCDA method proved that MCDA tools, and PROMETHEE II in particular, can provide excellent support in decision making in wind power development. Wide variety of input data, as well as the various and often contradicting interests by different stakeholders can be taken into account, while, at the same time, a clear result that can assist in decision making, is generated.

  • 5.
    Antonelli, Jacopo
    Gotland University, School of Culture, Energy and Environment.
    Reduced order modeling of wind turbines in MatLab for grid integration and control studies2012Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The current trend in the wind power industry is to develop wind turbines of constantly increasing size and rated power, as well as wind farms of growing size and installed wind power. A careful study of the behaviour of the wind turbines during their operation is of crucial importance in the planning phase and in the design stage of a wind farm, in order to minimize the risks deriving from a non accurate prediction of their impact in the electric grid causing sensible faults of the system.

    To analyze the impact of the wind turbines in the system, motivates the development of accurate yet simple models.

    To be able to practically deal with this topics, a simple model of a wind turbine system is investigated and developed; it has the aim to describe the behaviour of a wind turbine in operation on a mechanical standpoint.

    The same reduced order simple model can also be employed for control system studies; the control system model that can’t be used in generation, can use the reduced model. Together with the analytical description of such model, is realized a MatLab code to numerically analyse the response of the system, and the results of the simulation through such code are presented.

    The objective of this thesis has been to provide a simple benchmark tool in MatLab for grid integration and control studies for interested researchers.

  • 6.
    Baghirli, Orkhan
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Comparison of Lavenberg-Marquardt, Scaled Conjugate Gradient and Bayesian Regularization Backpropagation Algorithms for Multistep Ahead Wind Speed Forecasting Using Multilayer Perceptron Feedforward Neural Network2015Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Wind speed forecasting is critical for wind energy conversion systems since it greatly influences the issues such as scheduling of the power systems, and dynamic control of the wind turbines. Also, it plays an essential role for siting, sizing and improving the efficiency of wind power generation systems. Due to volatile and non-stationary nature of wind speed time series, wind speed forecasting has been proven to be a challenging task that requires adamant care and caution. There are several state-of-the-art methods, i.e., numerical weather prediction (NWP), statistical, and hybrid models, developed for this purpose. Recent studies show that artificial neural networks (ANNs) are also capable of wind speed forecasting to a great extent. 

    In this paper, 3-layer perceptron feedforward neural network is employed for comparison of three different training algorithms, i.e., Lavenberg-Marquardt (LM), Scaled Conjugate Gradient (SCG) and Bayesian Regularization (BR) backpropagation algorithms, in the view of their ability to perform 12 multistep ahead monthly wind speed forecasting. Horizontal wind speed, absolute air temperature, atmospheric pressure and relative humidity data collected between November 1995 - June 2003 and July 2007 – April 2015 for city of Roskilde, Denmark is used for training, validation and testing of the network model. The performed experiment shows that for 12 multistep ahead wind speed forecasting, SCG algorithm has obvious preference in terms of prediction accuracy with mean absolute percentage error (MAPE) of 3.717%, followed by LM and BR algorithms with MAPE of 4.311% and 4.587% accordingly. As a result, within the scope of this study, SCG algorithm is found to be more suitable to build a multistep ahead wind speed forecasting model.

  • 7.
    Barney, Andrew
    Gotland University, School of Culture, Energy and Environment.
    Making the Most of Wind: a Business Perspective on Subsidy Systems in France, Germany, Spain and Sweden2012Independent thesis Advanced level (degree of Master (One Year)), 40 credits / 60 HE creditsStudent thesis
    Abstract [en]

    Determining which countries are the most financially attractive for businesses to build wind projects is a matter of serious discussion that lacks succinct commentary. To fill this void this paper employs an empirical study of the wind subsidy support systems used by Germany, France, Spain and Sweden. This paper is based on the premise that businesses prefer to build where they can find the highest overall remuneration for their production; recognizing also the need for stability in those payments and businesses’ strong preference for larger early returns on their investments. The paper also analyzes the results and gives recommendations on possible improvements to each country’s system and where businesses should invest.In order to reach their 20-20-20 E.U. goals (European Commission, 2010), countries are encouraging the creation of new green energy projects, and this encouragement is frequently in the form of subsidies. The subsidy types used by the countries reviewed are feed-in tariffs, premiums and a certificate quota system. Each country’s support history is detailed along with the criteria of their respective systems.The countries systems are then compared using actual income and production data for four criteria at three different production levels – 100 percent, 75 percent and 150 percent of actual – and at two different lengths of time, 7 and 20 years. The first criteria of the comparison is total income, the second for variability of payments, the third for timing of payments and the final is the stability of the system itself.The results of this research show that the German and French systems are superior at all levels for their low variability in payment prices and in making larger payments to businesses earlier. They are also generally superior at lower and actual production levels for total income amounts. However, the Spanish options are superior at high levels of production for income and have middling variability levels. The Swedish system generally has the highest levels of variability for the lowest levels of income. Only the Spanish system is considered to be unstable in its political support of subsidies. Based upon the preceding findings are given to each country to improve their relative weaknesses. Also recommendations are given to businesses based upon the quality of the locations wind resources.

  • 8.
    Bezbradica, Marko
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Wind Farm Repowering: A Strategic Management Perspective2015Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    With an estimated wind turbine service life of 20-25 years, it is evident that in the coming years, an increasing number of wind farm owners will have to make a decision between decommissioning and repowering their wind farms. Even though repowering is underlined with a highly complex decision making process, a review of the literature suggests that it is mainly regarded as an engineering feat with a lack of discussion in the strategic and project management context.

    The objective of this thesis is to provide a framework that demonstrates the applicability of fundamental strategic and project management concepts on repowering and present a new perspective on this activity with a relatively short and promising history. In an effort to accomplish this, an extensive literature review analyzed different aspects of repowering through the lenses of strategic and project management. These concepts were then combined into the Repowering Strategic Project Management (RSPM) framework to guide the decision maker in selecting and implementing the optimal repowering strategy by establishing a repowering project early in the existing wind farm’s operational life.

    The RSPM framework presents a step-by-step guidance tool that demonstrates the process from envisioning an optimal end of service life (EOSL) solution to the repowering execution. In an effort to verify its suitability, the framework has been implemented, demonstrating the wide range of aspects the decision maker has to take into consideration suggesting that an early development of the repowering strategy and its corresponding project could help the owner to repower the wind farm in the most time-efficient manner. Lastly, while the thesis did not emphasize the evaluation and selection of strategy, the implementation of the RSPM framework provided guidelines for these tasks. 

  • 9.
    Boquist, Pär
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    OFFSHORE WIND POWER INVESTMENT MODEL USING A REFERENCECLASS FORECASTING APPROACH TO ESTIMATE THE REQUIRED COSTCONTINGENCY BUDGET2015Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Forecasting capital expenditures in early stages of an offshore wind power project is aproblematic process. The process can be affected by optimism bias and strategicmisrepresentation which may result in cost overruns. This thesis is a response to issuesregarding cost overruns in offshore wind power projects. The aim of this thesis is tocreate a cost forecasting method which can estimate the necessary capital budget in awind power project.

    The author presents a two-step model which both applies the inside view and outsideview. The inside view contains equations related to investment and installation costs.The outside view applies reference class forecasting in order to adjust the necessary costcontingency budget. The combined model will therefore forecast capital expenditures fora specific site and adjust the cost calculations with regard to previous similar projects.

    The results illustrate that the model is well correlated with normalized cost estimationsin other projects. A hypothetical 150MW offshore wind farm is estimated to costbetween 2.9 million €/MW and 3.5 million €/MW depending on the location of the windfarm.

  • 10.
    Borràs Morales, Jan
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Park optimization and wake interaction study at Bockstigen offshore wind power plant2014Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Losses for wake effects in offshore wind farms represent about 10% to 20% of the park annual energy production. Several analytical wake models have been developed and implemented to predict the power deficit of a wake-affected wind turbine. Validating and parameterizing the wake models available in the industry is essential to better predict the wake losses and thus maximize the energy yield of future offshore developments.

    In this study, a wake model validation is undertaken for the three models available in the commercial software WindSim. Data from Horns Rev wind farm is used to that purpose. Next, the models that show the best agreement with the observations are parameterized to better describe the power losses of a future offshore wind farm at Bockstigen. To finish with, an optimization sensitivity study is carried out and a final optimal layout is determined according to the seabed depth.

  • 11.
    Braunova, Vendula
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Impact Study of Wind Power on Tourism on Gotland2013Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This study investigates the impact of wind power on tourism on Gotland. The main objective is toidentify how tourists on Gotland during their holidaying perceive the visual features associated withwind turbines in the landscape. Additionally, it is sought to establish whether tourists plan to return toGotland despite the presence of wind power installations, with a special focus on first-time tourists.Using a structured questionnaire technique on a sample size of 735 respondents, this study reveals that8% of tourists perceive wind turbines negatively. Next, the study identifies that the decision to returnto Gotland of absolute majority of tourists, including first-time visiting tourists, is not impacted by thepresence of wind turbines. Lastly, it has been concluded that a potential on the island exists to developa form of ‘wind power tourism’.

  • 12.
    Braña, Isaac
    Gotland University, School of Culture, Energy and Environment.
    Turbine-Mounted Lidar:The pulsed lidar as a reliable alternative.2011Independent thesis Advanced level (degree of Master (One Year)), 40 credits / 60 HE creditsStudent thesis
    Abstract [en]

    Expectations for turbine-mounted lidar are increasing. The installation of lidars in wind turbine nacelles for measuring incoming winds, preventing wind gusts and increasing energy productions is after recently studies, technically and economically feasible. Among available lidar types, the most studied were continuous wave lidars because they were the most reliable apparatus when this initiative began. However, after studying technical considerations and checking commercial lidars, it was found that pulsed lidarslead this technology due to their promising results. The purpose of this report is to fill the gap between the interest in this technology and the absence of any academic papers that analyzes continuous-wave and pulsed lidars forthe mounted lidar concept. Hence, this report discusses the importance of turbine mounted lidars for wind power industry, different possible configurations and explains why specifically pulsed lidars are becoming more important for the mounted lidarmarket.

  • 13.
    Crasilşcic, Veaceslav
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    STUDY OF REQUIREMENTS FOR POST-CONSTRUCTION AUTOMATED BIRD MITIGATION SYSTEMS FROM STAKEHOLDER’S PERSPECTIVE2016Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The expansion of wind power comes with additional risks for bird populations, one of which is the collision with wind turbine components, mainly the rotating blades. In order to mitigate this risk, few systems on the market propose solutions with modules that deter the birds from the wind turbine or trigger the temporary shutdown of the turbines.The thesis seeks to obtain a common view from different stakeholders in order to create a list of requirements that the bird protection systems must have so as to be accepted by all the parties involved in the wind industry in Sweden. In order to meet this objective, interviews were conducted with interested stakeholders. Consequently, the interviews were summarized and common points were extracted to create a list of requirements and additional suggestions.Firstly, a comprehensive literature review was done that has pointed out issues like impacts of wind farms on bird species, especially raptors, causes of bird mortality, environmental legislation in European Union and Sweden, and current solutions on mitigating the risk of collisions with wind turbines onshore. Additionally, the author looked up into the most efficient ways to engage the stakeholders in constructive discussions and develop an easy framework for presenting the requirements.The primary data was collected through interviews with stakeholders representing 12 organizations. In the next steps, the data was analyzed by summarizing each interview and identifying the common and differentiating points in respondents’ views and suggestions over automated bird mitigation systems. The identified points laid the basis for a list of requirements considered important for safe and efficient bird mitigation systems in Sweden. Among others, stakeholders identified that the most crucial issues regarding bird mitigation systems are the response time to shutdown of the turbine, distance from the birds’ species living areas, need of species identification in bad weather conditions and night time and overall financial feasibility of such technologies.

  • 14.
    da Silva Soares, José Pedro
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    WIND ENERGY UTILIZATION IN ARCTIC CLIMATE – RACMO 2.3 GREENLAND CLIMATE RUNS PROJECT2016Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The potential for wind power development in Greenland is evaluated based on the analysis of 58 years of data (1957-2015) from RACMO 2.3 (Regional Atmospheric Climate Model). In order to create a wind power development tool, mesoscale maps based on RACMO 2.3 model were created containing the following characteristics: mean wind speeds (at 10 m), averaged maximum wind speed (with and without gusts at 10 m), temperature, humidity, geopotential, ice sheet mask and land sheet mask. A relevant aspect for this thesis is the mean wind speed. Over Greenland, the lower mean wind speeds range from 2-3 m/s on the tundra areas near the coast. This is influenced by high temperature inversion over the arctic tundra which disintegrates the predominant katabatic flow leading to lower wind speeds. On the other hand, the highest mean wind speeds range from 6 to 10 m/s and are observed in the northeastern region, due to cyclonic activity over the Greenland Sea. Maps of both the mean wind speed and averaged maximum wind speed are combined in order to achieve the highest mean wind speed value while at the same time avoiding maximum wind speeds higher than the cut-off value of the selected turbine model. This map combination is synchronized with pre-determined construction constraints, resulting in the suggestion of three different sites (sites 4, 5 and 6) as potential targets for wind power development. Multi-level data is sorted for different heights (10, 35, 70, 100 and 120 m) to perform a micro-scale analysis exercise for the three different site suggestions. A Vestas V90 3MW with an 80 meter hub height is selected as the standard turbine model to be deployed at the three recommended positions and for use in further simulations using WindSim. Annual Energy Production (AEP) for these three turbines in the recommended locations is calculated based on the interpolation from the climatology data at 70 m which is closest to the turbines’ hub heights. The AEP results are compared and show that site suggestion 4 presents the best potential for wind power development, surpassing by 79% and 23% the production results from sites 5 and 6, respectively. Based on the study developed, it is concluded that the in terms of wind resource assessment the potential for wind power development in Greenland exists. However the selection of possible deployment sites should be carefully done and real measurements must be performed.

  • 15.
    Das, Bibhash
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Technical Due Diligence Assessment and Bayesian Belief Networks Methodology for Wind Power Projects2013Independent thesis Advanced level (degree of Master (One Year)), 40 credits / 60 HE creditsStudent thesis
    Abstract [en]

    A Technical Due Diligence (TDD) investigation is an important step in the process of obtaining financing, or in mergers and acquisitions, for a wind power project. The investigation, the scope of which varies depending on the stage and nature of the project, involves reviewing important documentation relating to different aspects of the project, assessing potential risks in terms of the quality of the information available and suggesting mitigation or other risk management measures where required.

    A TDD assessment can greatly benefit from increased objectivity in terms of the reviewed aspects as it enables a sharper focus on the important risk elements and also provides a better appreciation of the investigated parameters. This master’s thesis has been an attempt to introduce more objectivity in the technical due diligence process followed at the host company. Thereafter, a points-based scoring system was devised to quantify the answered questions. The different aspects under investigation have a complex interrelationship and the resulting risks can be viewed as an outcome of a causal framework.

    To identify this causal framework the concept of Bayesian Belief Networks has been assessed. The resulting Bayesian Networks can be considered to provide a holistic framework for risk analysis within the TDD assessment process. The importance of accurate analysis of likelihood information for accurate analysis of Bayesian analysis has been identified. The statistical data set for the right framework needs to be generated to have the right correct setting for Bayesian analysis in the future studies.

    The objectiveness of the TDD process can be further enhanced by taking into consideration the capability of the investing body to handle the identified risks and also benchmarking risky aspects with industry standards or historical precedence.

  • 16.
    Dayal, Kunal Kushal
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    OFFSHORE WIND RESOURCE ASSESSMENT, SITE SUITABILITY AND TECHNOLOGY SELECTION FOR BLIGH WATERS FIJI USING WINDPRO2015Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This thesis aims to carry out offshore wind resource assessment, site suitability and technology selection for Bligh Waters in Fiji, and perform energy calculations for a 10-12 MW model offshore wind farm as well as carry out a simple economic analysis.

    The objectives were achieved by assessing the offshore wind resources employing atmospheric reanalysis data from the WindPRO online database performing the data correlation using the Measure Correlate Predict (MCP) module of WindPRO. The best correlated wind speed closest to the microsite was computed to be about 6.5 m/s at a height of 10 m, with a dominant East-southeast (ESE) and South-southeast (SSE) wind directions. Furthermore, the wind turbine technology was selected to be Vestas V80-2.0MW Offshore wind turbine and Siemens SWT-2.3-93 (2,300 kW) wind turbine with wind turbine class IEC IA for the site using the analysis done by the WindPRO site compliance module.

    Moreover, energy calculations were performed for 10 MW and 11.5 MW model offshore wind farms using the best correlated datasets close to the micro-site. The best model offshore wind farm was found to be the 11.5 MW wind farm, which had an annual energy production of 40,327.5 MWh/year, a capacity factor of 40.0 %, park efficiency of 99.8 % and full load hours of 3507 hours/year. Each Siemens SWT-2.3-93 (2,300 kW) wind turbine of the 11.5 MW wind farm produces an average of 8,065.4 MWh annually. The wind farm has a simple payback time of approximately 8 years with an installation cost of USD $51,750,000 and AAR of USD $6,452,400. The cost of energy generation per kWh is computed to be USD $0.12. Thus, comparing this to the cost of energy generation by other renewable and conventional sources in Fiji, it can be concluded that it is feasible and potentially competitive to invest into offshore wind farms to support the national electricity grid in Fiji.

  • 17.
    DeSena, Geoffrey
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Improvement of RANS Forest Model via Closure Coefficient Modification2017Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    As wind farms continue to take up more land throughout Northern Europe, developers are looking to sparsely populated areas, particularly in northern Fennoscandia, which hosts strong winds but also mixed and patchy forests over complex terrain. The complexity makes wind resource assessments difficult, raising uncertainty and therefore cost. Computational fluid dynamics (CFD) has the potential to increase the accuracy and reliability of wind models, but the most common form of commercial CFD modeling, Reynolds averaged Navier-Stokes (RANS), makes limiting assumptions about the effect of the forest on the wind. The wind resource assessment and energy estimation tool WindSim® , developed by WindSim AS, utilizes a porous medium model of a homogeneous forest with the influence of the forest on the airflow as a drag force term in the momentum equations. This method has provided reliable wind speed results but has been less reliable in estimating turbulence characteristics. The measure we evaluate in this study is turbulence intensity (TI). In this investigation, we make two types of modifications to the model and evaluate their impact on the TI estimates by using a benchmark data set collected by Meroney [1]. The first method is a variable profile of leaf area index (LAI) to represent the physical shape of the forest more accurately, and the second is a series of modifications to the closure coefficients in the turbulence transport equations. These modifications focus on the work of Lopes et al. [2], who used a large eddy simulation (LES) model to show that the turbulence production terms originally proposed by Green [3], expanded upon by Sanz [4], and widely used in the industry are unnecessary. Our investigations found that the implementation of a variable LAI profile has a small but non-negligible effect and that the elimination of the production terms from the turbulence transport equations does lead to a significant reduction in TI immediately above the forest. Both methods have minor effects on wind speed estimates, but the modification of closure coefficients has a much more significant impact on the TI. The coefficients proposed by Lopes et al. [2] drastically reduce TI estimates, but the model is still unable to reflect the Meroney data throughout the forest. Continued modification to new closure coefficients in combination with a variable forest LAI and other modifications such as a limited length scale may lead to significant improvement in TI estimates in future models, but these modifications must be compared against real-world data to ensure their applicability.

  • 18.
    Desilets-Aube, Raphael
    Gotland University, School of Culture, Energy and Environment.
    Developing boundary conditions usingthe nesting technique on simple terrain: A study of wind and turbulence intensity proles sensitivity2011Independent thesis Advanced level (degree of Master (One Year)), 40 credits / 60 HE creditsStudent thesis
    Abstract [en]

    As wind industry is developing steadily oshore, the wind turbine spacing remainsa key element for maximizing revenues and reducing loading from turbineswake interaction. In the case of relatively close to shore oshore wind farms, orlarge arrays onshore, the turbulence intensity coming from dierent sectors canhave an eect on wake growth and decay. In an attempt to obtain wind featuresat site, some boundary conditions for micro-siting simulation are found, using acommercial RANS ow solver CFD software was used. The approach in this workcould be described more practical than theoretical and could be more useful fordevelopers than pure CFD specialists.By simulating with three dierent roughness length for open sea, with theappropriate and contextual assumptions, for the oshore Lillgrund wind farm,vertical proles and turbulence intensity were extracted from the WindSim softwareat the meteorological mast position and enabled measurement comparison.In a second attempt to compare the eect of the wind and turbulence prolespreviously obtained, a sector of interest is simulated with the actuator disc model.In general, the site conditions over the large-scale domain evaluated by thecommercial software are satisfactory after adjusting the roughness length for theopen sea. The turbulence intensity trend for various in ow angle is capturedby the simulations and computed wind proles are for the most part adequately.A comparison of spring and winter ltered measurements enable discussion uponsome sectors disagreement. As for the small-scale actuator disc model using thedeveloped site conditions, the result is over-estimated by the simulations, especiallyfor the second row downstream.

  • 19.
    Dibennardo, Maurizio
    Gotland University, School of Culture, Energy and Environment.
    Performance based contracting: A concept for cost-effective operation and maintenance of wind power plants2011Independent thesis Advanced level (degree of Master (One Year)), 40 credits / 60 HE creditsStudent thesis
  • 20.
    Dragoi, Ion
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Comparison of optimization for non linear and linear wind resource grids2013Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The aim of this thesis is to assess how the configuration of linear and non-linearwind resource grids impacts the optimization.Three different software tools are used for this study: WAsP (linear model) includedin WindPRO, and WindSim (a non-linear model) - a CFD tool, and WindPRO forthe optimization. With the same configuration for wind resources, WAsP andWindSim will run to calculate the wind resource grids, .rsf or .wrg format, whichwill be compared in the post processing tab of WindPRO (from CFD interface).Using different optimization algorithms, the results from two software will becompared. The test site is flat terrain in the sea with no complexity (0,0002roughness and no orography or obstacle), and the chosen turbine here is Enercon40.3 (55m hub height, with the rated power at 14 m/s), and the wind is coming fromone direction, in our case North, which means sector 0.After comparison of the resource files from linear and non-linear wind resourcegrids, the optimization and comparison is ran for the two wind resource grids (linearand non-linear). The results of the optimization are also compared with optimizationresults of Eftun Yilmaz’s thesis (Eftun Yilmaz, 2013). We can see from the resultsthat WindSim gives almost 40% bigger values for the production. The results arecomparable with findings of Eftun Yilmaz thesis.

  • 21.
    Gallagher, Johnny
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    An Assessment of the Discrepancy Between Operational Assessment and Wind Resource Assessment for a Wind Farm in Ireland2014Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    An accurate wind resource assessment (WRA) is crucial in energy prediction as the power is directly proportional to the wind speed cubed. This thesis analyses the discrepancy between operational assessment and WRA for a wind farm located on a moderately complex terrain in Ireland. As part of this research, a WRA was undertaken and the results were input to two wind farm design tools, WindPro and WindSim, to estimate the annual energy production.

    Two and a half years of data was available from a 50m met mast. The data was analysed and filtered to ascertain and limit the usage of erroneous data. The dataset was then correlated with an available online dataset utilising the Measure Correlate Predict (MCP) module in WindPro in order to estimate the long term wind resource at the site.

    The wind resource was then used to determine the annual energy produced at the site using both WindPro and WindSim. A loss of 8% was applied to the energy calculations for comparison with the original WRA.

    The results demonstrate the energy production from the original energy prediction, undertaken by a leading wind consultancy prior to construction, was overestimated by an average 10.19% over the three years of operation. The averaged wind speed at hub height in the original WRA was 8.2m/s. However, the prediction undertaken using WindPro in this study estimated an average hub height wind speed of 8.0m/s while WindSim estimated an average of 7.36m/s. These differing results had a significant contribution to the difference in Annual Energy Production (AEP).

    The calculated annual energy results were an overestimation of energy production by an average of 8.10% utilising WindPro, while WindSim underestimated the energy output by just 0.11%.

  • 22.
    Giovannini, Gabriele
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Wind Farm decommissioning: A perspective on regulations and cost assessment in Italy and Sweden2014Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Due to a lack of knowledge and experience the best approach to deal with wind farm decommissioning has yet to be determined. To fill this void, this paper analyzed the current status in terms of regulations and cost, regarding the decommissioning in Italy and Sweden.

     

    In order to make a comparison between these two countries, the available research papers and reports on the decommissioning cost assessment, removal methods and regulations were thoroughly investigated. Moreover, detailed estimated dismantling cost data was obtained from a wind farm in Italy.

     

    The Italian cost data were compared with data collected in Sweden and along with them, the regulations and legislations related to how these costs have to be assessed as well as what developers are required to do regarding the decommissioning in the permit issuance were included.

     

    The results of this research show that in decommissioning cost assessment both countries does not allow developers to include the possible revenues due to the scraps and to the recycling of components, although totally different methods are pursued.

     

    Some kind of security to ensure that decommissioning occurs is required, normally a bond. The bond amount is a debt investment in which an investor loans money to an entity (corporate or governmental) that borrows the funds for a defined period of time at a fixed interest rate. In Italy the bond requirements are generally high and it has to be paid completely for the permit issuance. In order to develop significant projects, this kind of approach leads to discourage small investors.

     

    On the contrary, in Sweden the current amount of 300.000 SEK per turbine according to the court precedent, the most widespread during the approval of the permit, is definitely low and represent a level playing field for every investor. Swedish regulations are also more flexible and only in the 28% of the cases studied between the years 2009 and 2012, the entire amount of the bond had to be assured before the installation. However, the malleability with regard to wind farms that do not need to provide any security, together with the low bond amount might endanger the decommissioning accomplishment. 

  • 23.
    Guimarães da Silva, Jôse Lorena
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Computational sound propagation models: An analysis of the models Nord2000, CONCAWE, and ISO 9613-2 for sound propagation from a wind farm2017Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The recent goals from some countries to become renewable energy based and reduce carbon dioxide emissions have caused the wind industry to grow. Together, the size of the wind farms and the noise emission have grown, while the noise emission regulations have to be fulfilled. Numerical simulations based on engineering approaches are in many cases a fast alternative that may supplement actual sound measurements at the site on question. However, the sound propagation models have many assumptions and estimations, as different variants can affect the resulting sound propagation. The accuracy of the sound propagation models Nord2000, CONCAWE, and ISO 9613-2 are investigated in this research by comparing the predicted to the measured sound pressure levels from a wind farm in northern Sweden.

    Different parameters were investigated in each model, as wind speed and direction, roughness length, ground class, temperature gradient, and receiver height. The computational calculations were run on SoundPLAN software for a single point, the nearby dwelling. For the different parameters investigated, the settings were defined and inputted in the software, and the calculations were run. The equivalent sound pressure level results from the computational models were compared to the equivalent sound pressure level of the sound measurements filtered from background noise.

    The results indicate that the model ISO 9613-2 did not perform well for the specific site conditions at the wind farm. On the other hand, the CONCAWE and Nord2000 showed high accuracy, for downwind conditions at 8 m/s. For upwind conditions at 8 m/s, Nord2000 is more accurate, as the refraction of the sound rays are better calculated on this model. For the variants investigated on the Nord2000 model, the results that better approximate to the sound levels of the sound measurements are the roughness length 0.3, ground class D, and temperature gradient  0.05 K/m. Thus, these settings would be recommended for calculations with Nord2000 for noise assessment in a permit process.

  • 24.
    Haxsen, Sören
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    SUITABILITY OF THE EMD-CONWX EUROPE MESOSCALE DATA FOR WIND RESOURCE ASSESSMENTS2017Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The compilation of wind resource assessments and the implicit long-term correction ofwind measurements require comprehensive data sets. Commonly employed data sets forthis purpose are wind measurements from weather stations as well as SupervisoryControl and Data Acquisition (SCADA) data from existing wind farms. In addition,reanalysis data are a consistent data source. Reanalysis data are a combination ofmeteorological models with measurements of climatology parameters. To increase theperformance of reanalysis data the corresponding data sets are processed with mesoscalemodels. The present study determines the suitability of the readily accessible EMDConWxEurope Mesoscale Data (EMD-ConWx Data) for wind resource assessments.EMD-ConWx Data include hourly wind velocities at seven heights in the range of 10 mup to 200 m and have a spatial resolution of 3 x 3 km. EMD-ConWx Data are based onthe primary reanalysis data set ERA-Interim. The EMD-ConWx Data are compared toSonic Detecting and Ranging (Sodar) measurements at 22 sites in Germany regardingthe parameters wind speed, wind direction and wind speed frequency distribution. Inaddition, the statistical correlation (R) and linear regression (R²) are determined.It was found, that EMD-ConWx Data reveal a moderate accuracy for wind resourceassessments. The determined average wind speed bias of 1.02 m/s, the average rootmeans square error (RMSE) of 1.91 m/s, the average wind direction bias of -0.89° andthe monthly correlation indicate overall an adequate match with the Sodarmeasurements. However, these results entail considerable uncertainties and variances.To reduce these variances and the wind speed overestimation a height shift of 50 m forthe EMD-ConWx wind velocity heights is introduced. The comparison of the EMDConWxwind data at 50 m to Sodar measurements at 100 m leads to a significantreduction of the wind speed bias, but it improves neither the wind direction accuracy northe wind speed correlation. Overall, the EMD-ConWx Data are suitable for windresource assessments and the implicit long-term correction of wind data. The EMDConWxData with the height shift imply the advantage of a proper representation of thewind profile in relation to common reanalysis data, even at sites with complex terrain.

  • 25.
    HEKİM, MEHMET ÇAĞRI
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    WAKE EFFECT IMPACTS ON THE ENERGY PRODUCTION OF THREE WIND TURBINES IN CLOSE CONFIGURATION2015Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    With the rapid expansion of offshore wind power capacity in the world in the last decade, innovative offshore solutions are designed in order to meet the upcoming power capacity installations. As in all other energy sectors, offshore wind power has certain conditions that have to be met to increase the efficacy of the outcome.In this thesis, wake effect impact on the production results of Hexicon AB’s innovative floating and rotating offshore wind power platform project with 3 turbines located in the southern part of Sweden are analyzed through the application of “Analytical wake models” and the “Actuator Disc method”, with the help of WindSim.The results of Analytical models and Actuator Disc method were found to be independent of one another. Even though analytical wake models did not find any wake effect impact among the turbines, the results can be considered as logical. However, the Actuator Disc method created unexpected results which might stem from the WindSim – AD combination. It is therefore recommended to further explore these scenarios with other (more) advanced simulation tools.

  • 26.
    Hines, Paul
    Gotland University, School of Culture, Energy and Environment.
    WindSim Study of Hybrid Wind Farm in Complex Terrain2012Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    A annual nergy production analysis was undertaken to compare wind resources and annual energy production as estimated by WAsP and Windsim. Nordex Sverige AB has designed a wind farm with the help of WAsP and this study will involve the examination of this site with Windsim. Two site formations are of interest, one with the same class of turbine and one with a mix of two turbine types. The study is interested in the effect on annual energy production as estimated by the different software of employing a hybrid layout using wind turbines of different height.The results showed that whilst initial estimations of total energy production without wake losses appear very similar between WAsP and Windsim the ways in which the software are treating individual turbines within the planned farm can be quite different because of different physics. The analysis of the „hybrid‟ turbine layout showed significant increases in estimated annual energy production when a turbine with a higher tower and larger rotor diameter was used in a hybrid arrangement. Estimated annual energy losses on the turbines that were not changed in favour of a larger turbine were small. However, no great benefit in estimated turbine efficiency was achieved through the mixing of turbine types with different hub heights. The gains in annual energy production estimated by both software are however significant with increased production of 18 % across the entire farm when comparing the „hybrid‟ layout to a farm based on only the smaller of the two turbine types.

  • 27.
    Jansson, Anton
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    INVESTIGATING DIMMING OF OBSTRUCTION LIGHTS IN A SWEDISH WIND FARM2016Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The demand and need for alternative obstruction marking has become a significant challenge for the wind power development in Sweden. While the development of wind turbines pushes for higher heights, the need to denote them as possible obstacles for aviation increase. To reduce undesired effects of the aviation warning lights in the landscape, various technologies for reducing the light emitted have been developed. One of these technologies control the lights’ output by dimming them based on measurements of the prevailing visibility in the vicinity of the wind farm.Visibility controlled obstruction lighting has not yet been used in Swedish wind farms. This thesis will investigate how a system can be applied from different viewpoints and what would be gained in a wind farm in northern Sweden.By reviewing literature, interviewing key-persons, studying a case with application of Finnish regulations and estimating the performance during different conditions, and discussing the results, conclusions could be drawn. The findings are general recommendations for acceptance, an aviation risk that need to be considered, indications of preferable regulation applications and approximations of the performance and possible gain.

  • 28.
    Jayasinghe, Lahiru Kushan
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences. Cleps AB.
    Power Loss Evaluation of Submarine Cables in 500 MW Offshore Wind Farm2017Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The main objective of this thesis is to develop a new methodology to evaluate the transmission cable losses of wind-generated electricity. The research included the power loss variations of submarine cables in relation to the line length, cable capacity and the transmission technology in an offshore wind farm having a capacity of 500 MW. The literature of similar studies helped to generate a solid background for the research.

     

    The comprehensive analysis carried out is based on a hypothetical wind farm and using three different power transmission wind farm models to investigate the technical reliability of transmission technology, namely, High Voltage Alternative Current (HVAC), High Voltage Direct Current Voltage Source Converter (HVDC VSC) and High Voltage Direct Current Line Commutated Converter (HVDC LCC). The analyses carried out are performed under assumptions and simplifications of power system models to evaluate the submarine cable transmission losses of 3 different transmission systems by using the MATLAB/ Simulink software.

     

    With relevance to the simulation results, the HVAC submarine cable has more losses than any other transmission technology cables and it is suitable for short distance power transmission. The VSC technology has less losses than HVAC. Comparing with afore-mention technologies the HVDC LCC technology transmission links have the lowest line losses. Moreover, the transformer losses and the converter losses were calculated. The simulation results also included the overall power system losses by each of the transmission models.

  • 29.
    Johansson, Jim
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Utilizing Energy Storage Applied on Floating Wind Turbine Economics Using a Spot-Price Based Algorithm2017Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In this paper, a new algorithm for utilizing energy storage is proposed and applied on floating wind turbine economics. The proposed algorithm’s decision making on storing energy or selling electricity onto the grid is based on the electricity price, which makes it unique and different from similar algorithms. From the literature review, it was concluded Ocean Renewable Energy Storage to be most suitable with the Spar-Type and Semi-Submersible floating wind turbine to which the paper is based upon. The objective of this paper is to find the suitable ratio of energy storage versus wind farm, find the product of increase in wholesale, and evaluate whether the proposed method makes the hybrid economically sound. The algorithm was applied on spot-price data from Denmark due to its large share of wind energy with wind data from off the coast of Morro Bay in California, USA. Additionally, a sensitivity analysis is applied to evaluate to energy storage cost impact as well as evaluate the algorithm by lowering the required energy storage size.

     

    Using the algorithm, the wind farm must account for nine days’ worth of energy production with a product of energy storage versus wind farm ratio of 1.42. The wholesale price increased with 11.9-21.5% for the four years studied, however, all financial results favored not utilizing energy storage. By the results derived from the sensitivity analysis, it was concluded that with future cost reductions, the algorithm will still favor no energy storage. However, by fine tuning the algorithm to reduce the need for storage, positive financial result might be achievable. The key to achieve a profitable result seems to rely on minimizing the need for energy storage, to which the proposed algorithm fail to achieve. Conclusively, spot-price decision-based energy storing is not economically sound.

  • 30.
    Kaidis, Christos
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Wind Turbine Reliability Prediction: A Scada Data Processing & Reliability Estimation Tool2014Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This research project discusses the life-cycle analysis of wind turbines through the processing of operational data from two modern European wind farms. A methodology for SCADA data processing has been developed combining previous research findings and in-house experience followed by statistical analysis of the results. The analysis was performed by dividing the wind turbine into assemblies and the failures events in severity categories. Depending on the failure severity category a different statistical methodology was applied, examining the reliability growth and the applicability of the “bathtub curve” concept for wind turbine reliability analysis. Finally, a methodology for adapting the results of the statistical analysis to site-specific environmental conditions is proposed.

  • 31.
    Kasimoglu, Ata
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    The Impact Of Wind Energy Development On Swedish Elspot Day-Ahead Prices2018Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The rapid development of wind energy in Sweden created a volatile environment for the electricity market. Variance in the daily prices and the reductions of the average prices over the years due to the merit order effect of intermittent wind energy resulted in increased unpredictability in financial returns, which led to many wind projects being cancelled. In this thesis, in order to shed more light on the impact of wind energy development on spot prices, an artificial neural network (ANN) electricity price forecasting model is designed in order to predict Sweden’s four electricity regions Nord Pool Elspot day-ahead electricity spot market prices. The model's final result displayed a mean absolute error of 3.3398 €/MWh. In order for the model to be able to generalize better, a ridge regression regularizer is added to the ANN. Alternative wind scenarios for Sweden are introduced and their spot prices are predicted by the ANN model. The results show that each 10% increase in wind energy production leads to a 0.9% spot price reduction in the Nord Pool Swedish energy market prices.

  • 32.
    Kerkvliet, Hans
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    OFFSHORE WIND FARM DECOMMISSIONING: INTRODUCING A MULTI-CRITERIA DECISION AID APPROACH2015Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The objective of this Thesis is to develop a methodological framework to guide the decision maker in selecting a decommissioning method for offshore wind farms which is supported by the majority of relevant stakeholders. Initially, a literature review has been conducted to find out which methods are available to decommission an off-shore wind farm and which criteria can influence the outcome.Two methods have been found in literature, namely partial and total removal of the foundation. Furthermore, twenty one (21) criteria have been found which could influence the results. These criteria can be divided in four categories which are economical, environmental, social and technical.Subsequently, a methodological framework was developed that included four steps. First, the possible decommissioning methods should be identified. Following on that, information should be collected and stakeholders should be selected. Subsequently, criteria should be selected and as last a multi criteria decision aid method should be used. It is expected that this procedure would lead to a decommissioning method which is supported by most of the stakeholders.To validate the methodological framework, a case study in the Netherlands has been selected. For this case study, four (4) stakeholders were identified and eleven (11) criteria were assessed. The outranking multi-criteria decision aid method PROMETHEE II was selected and results were obtained. Analyzing the results, it was possible to conclude that only one stakeholder preferred the total removal method while the other three stakeholders preferred the partial removal method.

  • 33.
    Khatab, Abdul Mouez
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Performance Analysis of Operating Wind Farms2017Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This work proposes a methodology to evaluate the performance of operating wind farms via the use of Supervisory Control and Data Acquisition System (SCADA) and modeled data. The potential annual energy is calculated per individual turbine considering underperforming/loss events to have their power output in accordance with a representative derived operational power curve. Losses/underperformance events are calculated and categorized into several groups aiming at identifying and quantify their causes. The methodology requires both anemometry data from SCADA system as well as modeled data. The discrepancy of the data representing the valid points of the power curve is taken into consideration as well when assessing the performance, i.e. wind speed vs power output of events that are not loss/underperformance. Production loss and relative standard deviation of power output of what is defined as “valid sample” in this work (per each turbine) are the main results obtained in this work. Finally, a number of optimization measures are suggested in order to enhance the performance, which can lead to a boost in the financial output of a wind farm.

    Aiming at judging the reliability of the proposed methodology, a case study is conducted and evaluated. The investigated case study shows that the methodology is capable of determining potential energy and associated losses/underperformance events. Several questions were raised during the assessment and are discussed in this report, recommendation for optimization measures are presented at the end of the study. Also, a discussion on the limitations and uncertainties associated to the presented methodology and the case study.

  • 34.
    Koebel, Evan
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Maximizing Local Acceptance through Benefit Sharing2011Independent thesis Advanced level (degree of Master (One Year)), 40 credits / 60 HE creditsStudent thesis
    Abstract [en]

    Local opposition has been widely recognized as a potentially powerful barrier to the successfuldevelopment of wind power projects. As a result, there has been increasing pressure put on industryproponents to adopt comprehensive strategies aimed at increasing local acceptance. The concept ofbenefit sharing is becoming more widely recognized as an effective method of doing so.A comparative analysis of wind power projects throughout Europe has demonstrated considerablevariability both in terms of the quantities and qualities of benefit sharing mechanisms applied. Despitethis variability, however, there does appear to be a tendency toward establishing community funds tosupport certain initiatives in the host locality. Developers have also offered local ownershipopportunities, electricity price reduction for community members, knowledge sharing and/oreducational initiatives, local employment opportunities, and some have undertaken extensiveenvironmental restoration or enhancement projects. The key factors influencing the development of abenefit sharing strategy are the national context, the organizational competencies of the developer andthe local context. Careful consideration of these factors will inform the creation of an effective benefitsharing scheme.However, the application of a benefit sharing scheme in itself does not guarantee acceptance, but rathermust be integrated with effective public engagement and participation in decision making throughwhich the needs, wishes and demands of the host community are addressed and incorporated into theproject details, where possible. Overall, based on the influences of the national context in combinationwith the specific competencies of the developer, organizations are recommended to adopt formalized,yet flexible policies or strategies for benefit sharing in each country where they operate, which can thenbe adapted to the unique circumstances of each project and community.

  • 35.
    Kollwitz, Jochanan
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Defining the Wake Decay Constant as a Function of Turbulence Intensity to Model Wake Losses in Onshore Wind Farms2016Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Modelling the wake effect generated by wind turbines is an essential part for calcu- lating a wind farm’s expected energy production. Operating wind turbines disturb the flow of the wind, which results in decreased production of downwind turbines. The N. O. Jensen model is an industry standard wake model that assumes a linear expansion of the downstream wake. The only adjustable parameter in the model is the wake decay constant (WDC), which has traditionally been derived semi em- pirically from terrain surface roughness. However, the WDC defines the expansion rate of the generated wake, and therefore can be linked to the ambient turbulence intensity (TI): high ambient turbulence leads to a faster decay of the generated wake, and therefore to lower wake losses, and vice-versa. Since the influence of the roughness on the ambient turbulence intensity is expected to be less significant at higher heights, these roughness-based WDC values are rather uncertain for the hub heights employed nowadays.

    The following study presents the results of a comparison between observed and mod- elled wake losses based on different WDC values. To investigate how a change in height affects the wake modelling, two wake scenarios occurring between two tur- bine sets with different hub heights are selected from an operational wind farm. By modelling the wakes using roughness as well as turbulence intensity-based WDCs, conclusions can be drawn on how the predictive capability of the N.O. Jensen model depends on the selection of a suitable WDC value.

    Finally it is concluded that the goodness of fit between modelled and observed wake losses shows a clear dependency on the wind speed/power production inter- val. At higher wind speeds, the TI-based WDC resulted in a better accuracy of the modelled wake losses as compared to the roughness-based WDC, while for lower wind speeds the N. O. Jensen model performed most accurately when using WDC = 0.075. However, for the investigated cases the overall accuracy of the modelled wake appears to be higher when choosing WDC = 0.075 instead of a TI-based WDC. 

  • 36.
    Kumar, Bhunesh
    Gotland University, School of Culture, Energy and Environment.
    Design of Harmonic Filters for Renewable Energy Applications2011Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Harmonics are created by non-linear devices connected to the power system. Power system harmonics are multiples of the fundamental power system frequency and these harmonic frequencies can create distorted voltages and currents. Distortion of voltages and currents can affect the power system adversely causing power quality problems. Therefore, estimation of harmonics is of high importance for efficiency of the power system network. The problem of harmonic loss evaluation is of growing importance for renewable power system industry by impacting the operating costs and the useful life of the system components.

    Non-linear devices such as power electronics converters can inject harmonics alternating currents (AC) in the electrical power system. The number of sensitive loads that require ideal sinusoidal supply voltage for their proper operation has been increasing. To maintain the quality limits proposed by standards to protect the sensitive loads, it is necessary to include some form of filtering device to the power system. Harmonics also increases overall reactive power demanded by equivalent load. Filters have been devised to achieve an optimal control strategy for harmonic alleviation problems.

    To achieve an acceptable distortion, increase the power quality and to reduce the harmonics hence several three phase filter banks are used and connected in parallel. In this thesis, high order harmonics cases have been suppressed by employing variants of Butterworth, Chebyshev and Cauer filters. MATLAB/SIMULINK wind farm model was used to generate and analyze the different harmonics magnitude and frequency. High voltage direct current (HVDC) lines for an electrical grid that is more than50km far away wind farm generation plant was investigated for harmonics. These HVDC lines are also used in offshore wind farm plant. Investigated three-phase harmonics filters are shunt elements that are used in power systems for decreasing voltage distortion and for correcting the power factor.

    Renewable energy sources are not the stable source of energy generation like wind, solar and tidal e.t.c. Though they are secondary sources of generation and hard to connect with electrical grid. In near future the technique is to use the wave digital filter (WDF) or circulator-tree wave digital filter (CTWDF) for the renewable energy application can be employed to mitigate the harmonics. These WDF and CTWDF can b eused in HVDC lines and smart grid applications. A preliminary analysis is conducted for such a study. 

  • 37.
    Lee-Jones, David
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    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 credits / 15 HE creditsStudent thesis
    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.

  • 38.
    Liapodimitris, Dimitrios
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    VESSEL FLEET OPTIMISATION FOR OFFSHORE WIND POWER MAINTENANCE2017Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    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.

  • 39.
    Lynch, Keith
    Gotland University, School of Culture, Energy and Environment.
    Proposed Methodology forTechnical Due Diligence Assessment of Wind Farm Projects2011Independent thesis Advanced level (degree of Master (One Year)), 40 credits / 60 HE creditsStudent thesis
    Abstract [en]

    Technical Due Diligence (TDD) is an extensive document review process in which a complete assessment is made of all potential risks to the realisation or successful operation of a wind farm project. The goal of this assessment is to determine thecommercial feasibility of the proposed project. TDD assessments are extensive undertakings, and potentially subject to the bias of the individual reviewer. This aim of this research project is to develop a methodology to assist in the completion of TDD reviews at the host company for this research project, Mecal Wind Farm Services B.V., which will reduce the subjectivity of the TDD analysis and allow for objective comparison between different projects. A methodology was developed which assists the TDD assessment process. This methodology uses the combined judgements of individual reviewer and project managerto apply a weighting to the risk assessments carried out as part of the review. Aspreadsheet tool was created, based on this methodology, to assist the completion ofTDD assessments at Mecal.The spread sheet tool was validated by reference to historic project data at Mecal. The output of the tool compared well with the outcome of the project, proving that theconcept and methodology of the tool is sound.

  • 40.
    Malmsten, Jon
    Gotland University, School of Culture, Energy and Environment.
    Wind Turbine Production losses in Cold Climate: case study of ten wind farms in Sweden2011Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    As wind power expands rapidly worldwide, it is becoming more common to build wind farms in alpine locations where the wind resources often are good and conflicting interests are few. This is evident in Sweden where a substantial portion of the large wind parks planned are to be built in cold climate locations. The fact that icing of turbine blades and sensors can severely impact the production raises the question how large the losses are. In this thesis 10 wind parks comprising 45 turbines, well dispersed throughout Sweden are investigated. Daily production figures are compared to wind data from the MERRA reanalysis data-set in order to see if it is possible to determine the level of losses during the winter period caused by cold climate.

    A method is suggested where a relationship between daily production and daily average wind speed is established using representative summer days. This relationship is then used to calculate an expected production for the winter period. Losses are concluded as the difference between expected and actual production.

    The method did not produce a consistent and reliable result for the sites investigated. However, the method captures the overall trend with higher losses in the north of Sweden compared to the sites in the south where little or no icing is likely. At the sites where icing is expected, losses in the range of 10 to 20% of the annual production were calculated.

  • 41.
    Mancebo, Carlos Díaz-Asensio
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    COMPARISON STUDY FOR WIND RESOURCE ASSESMENT IN COMPLEX DOMAIN USING METEODYN AND WINDSIM2014Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Two commercial Computational Fluid Dynamic (CFD) wind resource assessment tools namely Meteodyn WT and Windsim have been compared for an embankment site named Hjardemål. For comparison of both software, a controlled experiment is carried out for a fixed set-up with same domain size and same number of cells in the X, Y and Z directions. Wind flow has been assessed in the perpendicular upstream direction to the embankment. Vertical wind profiles observed on site at four different towers distributed (-397.69 m) before, (0 m) at, (30.83 m) just after and (199.16 m) after the embankment are compared with both software outputs. Results show that Meteodyn WT predicts closer vertical wind profiles before, at and after whilst wind Windsim predicts a closer wind profile just after the embankment. The discussion of results is based on the limitations of both software tools which have conditioned the comparison.

  • 42.
    Manouchehrabadi, Maryam Kharaji
    Gotland University, School of Culture, Energy and Environment.
    Reliable Centered Maintenance (RCM) Reliable and Risk Centered Maintenance (RRCM) in Offshore Wind Farms (Case Study- Sweden)2011Independent thesis Advanced level (degree of Master (One Year)), 40 credits / 60 HE creditsStudent thesis
    Abstract [en]

    Wind power, as a source of renewable energy, is growing very fast. Especially so, is consideration given to offshore wind farms where expansion is due in part to limited social and visual impact, reduced noise effect of turbines, and at the same time higher production of offshore wind turbines. Maintenance is always a considerable and costly part of the wind power investment, especially for offshore projects, but it could not improve as fast as the increasing wind industry in the world. The operation and maintenance management of wind farms should have always a reliable and structured planning to have an economical investment. At the beginning of the growth of wind industry, companies tried to transfer responsibilities of the failure and loss of production to the insurance companies, but it cannot be continued any more. These days even the insurance companies ask about regular inspection or condition monitoring. In other words, they ask for a reliable strategy for operation and maintenance. Both preventative and corrective maintenance are used in offshore wind farms. Preventive maintenance is usually performed at the first sign of failure, and in so doing it helps reduce costs associated from lost production. Having a perfect preventive maintenance program is not easy and it usually needs more inspection and online monitoring. To select a suitable strategy, data should be gathered from different stakeholders who are involved in the project. The stakeholders could be turbine designers, construction companies, transportation companies, operation staff, etc. The reason is that each group has the data which could help to define a reliable strategy of maintenance. Reliability includes measurements, e.g., failure rate, repair time, and availability. Reliability is the ability of components or system to perform their function under given operational condition and for a predicted period of time. However always preventive maintenance especially for offshore wind farm is faced with uncertainty due to bad weather, access difficulty, and logistic limitation. Reliability Centered Maintenance (RCM) is a systematic qualitative technique that balances preventive and corrective maintenance. It chooses the right preventive maintenance activities for the right component at the right time to reach the most cost efficient solution. This research points out that RCM, as an experienced methodology in other industries, could be a good method for scheduled preventive maintenance in offshore wind power for purposes of lowering cost while improving reliability and safety. RCM implementation is always facing with uncertainty. Engaged uncertainty to RCM is known as Reliability and Risk Centered Maintenance RRCM and it could lead maintenance process to an optimal preventive schedule with minimum uncertainty.

  • 43.
    Maruf, Shafiul Murshed
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    WIND RESOURCE ASSESSMENT AND SITE SUITABILITY IN BANGLADESH USING WINDPRO AND WINDSIM2015Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The purpose of this thesis is to find suitable places in Bangladesh for wind power development and to promote for further studies in this scenario. In this thesis, three onshore places have been chosen for analyzing using powerful state of the art software tools. As through investigations, no published research paper has been found that shows CFD (Computational Fluid Dynamics) and WAsP engineering had been used to analyze site suitability and predict the potential for wind energy in Bangladesh. Two of three places are close to the coast line which prove that the sites are suitable for developing wind power project and initiate further studies too.WindPRO, WindSim, WAsP and WAsP Engineering are used for site suitability assessment, annual energy production estimations, wind resource mapping and site compliance. The whole process of methodology will be explained step by step using images with description. The important simulation results have been added in appendix.After running all simulations, two sites in coastal areas are highly potential for wind power development. And the other site also has potential too. The results in site compliance show that the local climate is suitable for installation of wind turbines.Bangladesh is far behind in terms of wind power development. Only 3 MW have been installed in coastal regions as a testbed.Bangladesh has a costal belt of around 724 km along the Bay of Bengal which is also included many islands in the border of Bangladesh territory. Geographically, strong south-south-east monsoon wind comes from Indian Ocean and after traveling a long distance over the water surface, enter into Asia over the coastal area of Bangladesh. According to a wind atlas data, produced by Denmark; Bangladesh has good wind resources over the land especially on the Bay of Bengal and its coastal line.All the studies on wind resources show that Bangladesh has not only penitential in offshore wind power as well as onshore base wind power projects. Only the coastal areas contain wind power potential is more than 20,000MW which can supply electricity whole Bangladesh 3 times over.

  • 44.
    Mathers, Adam
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Community Benefit Funds and Wind Power: A Scottish Case Study2018Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The Scottish government’s aim of deriving 100 per cent of the nation’s electricity from renewable sources is dependent on the utilisation of wind energy. Social barriers, however, have continued to threaten these targets. Community benefit funds have often been paraded as the most common way of improving public attitudes towards wind farms in the United Kingdom, although little empirical evidence exists to support this notion. Using the proposed Ourack wind farm, approximately three and a half miles north of Grantown-on-Spey in the Scottish Highlands, this case study, consisting of a sequential explanatory research design comprised of an initial close-ended survey followed by in-depth semi-structured interviews, sought to explore the community’s perceptions of community benefits, identify the type of fund that the community wanted, and investigate the role of such benefit provisions in altering perceptions of wind farms. The key findings indicated that the majority of participants were in favour of benefits being provided, they preferred funding to be directed towards community organisations, and approximately one third of research participants (31.6 per cent) perceived the proposed wind farm in a more positive light after considering the possible benefits the region would accrue. Furthermore, the research indicated the need for community benefits to become a standardised part of the planning process, thus reducing the likelihood of financial benefits being perceived as bribes, and allowing developers to provide greater information about any proposed benefits scheme prior to applying for planning permission. There are implications of this study for academics researching the role of community benefits in wind farm planning, and policymakers and developers for understanding the wants and needs of community members.  

  • 45.
    McCarthy, John
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    WIND FARM DECOMMISSIONING: A DETAILED APPROACH TO ESTIMATE FUTURE COSTS IN SWEDEN2015Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Although targets for renewable energy exist in Sweden, developing wind energy has proven to be challenging for developers. This is due in part to the demands made by authorities for monetary amounts to be set aside to take care of wind turbine dismantling and site restoration costs at the end of their lifecycle. There has been a large degree of uncertainty surrounding the amounts being demanded and the level to which sites must be restored, partially due to a lack of guidelines. Coupled with ambiguity, there has been a tendency by authorities and developers to use figures from previous high court decisions and previous permit applications to project decommissioning costs for current applications.This thesis evaluates seven different wind farm decommissioning scenarios using a model developed to estimate future costs, with the turbine model and the quantity of turbines being the parameters that vary. The model uses data from numerous sources, including real case decommissioning projects and figures from an existing model that had already been used to forecast costs in Sweden. One of the assumptions of the model developed is that scrap metals in wind turbines will have a residual value when decommissioning occurs; this was not allowed for in a recent decision made by a county administrative board following an environmental high court decision. An argument is made to justify that a minimum scrap value for wind turbines should be considered, based on the findings of the model. A further case is made to allow for the security bonds to be paid over an extended period of time, considering the initial value of wind farms.The results of the model show that the turbine model has an impact on the decommissioning costs and the potential residual value that can be obtained. In addition, the quantity of the wind turbines has a considerable effect on the decommissioning costs. These results suggest that each wind development project should be treated on a case-by-case basis using a calculation-based approach when determining the cost for a security bond. Recommendations for future research include considering wind farm location in the model.

  • 46.
    McNally, Ross
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    MOVING TOWARDS BEST PRACTICE FOR BIRD MORTALITY MITIGATION IN WIND POWER PLANNING, SWEDEN2015Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This thesis investigates the potential for moving towards a best practice for bird mortality mitigation within wind power planning in Sweden. Best practice in this sense involves stakeholder collaboration and consensus on methods for reducing the risk of bird mortality at wind farms in Sweden in line with current legislation.

    The main objective was to highlight issues and reach consensus on solutions in relation to bird mortality and disturbance of avifauna in onshore wind power development through the engagement of relevant stakeholders. The secondary objective of the thesis was to evaluate the effectiveness of the collaborative stakeholder workshop method used for use within renewable energy planning conflicts of interest.

    The primary data collection method or means used for the thesis was a collaborative stakeholder workshop designed and organized by the author, focused upon building trust among relevant real life stakeholders and a co-evolution of stakeholders towards potential mitigation solutions to bird mortality and disturbance of avifauna within onshore wind power development. The workshop was hosted and facilitated by the author on 19th May 2015 at Uppsala University, Campus Gotland. To compliment this approach a semi-structured interview was custom designed for relevant stakeholders unable to attend the workshop. An analysis of court cases relating to bird mortality in wind power planning was also undertaken with the aim of shedding light on interpretations of legislation relating to bird mortality and disturbance in wind power planning.

    The results show stakeholders across both data collection methods agreeing upon the importance of pre-screening and siting of wind turbines as the most important step in moving towards a best practice. In addition the majority of stakeholders highlighted the importance of post-construction mitigation technologies such as DTBird and IdentiFlight to be used as a secondary option within low risk areas once validated. In addition the results highlight a general lack of knowledge relating to the interpretations of relevant legislation among stakeholders.

    The analytical findings point towards the importance of engagement, consensus, validation and knowledge in moving towards a best practice for bird mortality mitigation in wind power planning in Sweden.

    Regarding innovation, the thesis has at least furthered dialogue in relation to best practice of bird mortality mitigation in wind power planning for Sweden and at best put forward a potential solution in an adaptive planning model for the island of Gotland in Sweden using IdentiFlight technology for further discussion and/or development. The thesis also highlights the potential of community planning influenced stakeholder engagement to applied problems within wind power planning in Sweden. Finally the author’s collaborative method designed for the workshop was considered useful through a stakeholder evaluation survey and could perhaps be developed further.

    The major limitations of the thesis related to the logistics behind organizing a stakeholder workshop. It was difficult to have a fully representative sample at a national level and in this regard the workshop was considered to be of more relevance for the island of Gotland. The complimentary stakeholder interviews were designed to partially compensate for this bias, but again were limited due to finite time and resources.

  • 47.
    Menin, Michel
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Parametric sensitivity study for wind power trading through stochastic reserve and energy market optimization2015Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Trading optimal wind power in energy and regulation market offers possibil-ities for increasing revenues as well as impacting security of the system in apositive way[33]. The bidding in both energy and regulation markets can bedone through stochastic optimization process of both markets.Stochastic optimization can be possible once the probabilistic forecst is avail-able through ensemble forecast methodology. For stochastic optimization, thepost-processing of the ensembles to generate quantiles that will be used in op-timization can be accomplished by employing different methodology. In thisstudy, we will concentrate on the impact of post-processing of ensembles onthe stochastic optimization.Generation of quantiles needed for stochastic optimization used herein formarket optimization will be the main focus of the investigation. The impactof price ratios between energy and reserve market will be also investigated toanalyse the impact of said ratios on the revenues. Furthermore this analysiswill be performed for both US and Swedish markets.

  • 48.
    Montenegro Borbolla, Ivan
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Using refurbished turbines to provide affordable wind energy: A case study in Africa2015Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    When a wind farm is repowered, decommissioned turbines are discarded. This creates a stock of wind turbines that can be acquired for a fraction of the original cost, and refurbished. Taking advantage of the reduced price and the ruggedness of first generation wind turbines, new markets for sale of wind energy can be explored.

    This thesis first analyses the repowering background of Germany, Denmark, and other European countries, where transition to repowered or “second generation” wind farms is taking place.

    Then, a number of feasibility studies are reviewed to create a study framework, which will allow in-depth study of suitable energy markets. Using this framework, the suitability of four countries is analysed in detail: Djibouti, Madagascar, Mozambique, and Tanzania.

    Two countries are selected to perform a total of 6 site studies: Djibouti and Tanzania. Using WindPro 2.9, six model wind farms are simulated. A financial model is built, based on an NREL study, to analyse the economic viability of wind farms.

    Using the financial model, the levelized cost of energy is obtained, and used to evaluate the competitiveness of the model wind farms. A sensitivity study is carried out to identify the major influences on the LCOE. Using the cost data, the cost competitiveness of the proposed wind farms is discussed, including competitiveness in the target markets, and a cost comparison with commercial wind farms with new turbines is performed. Five out of six proposed wind farms are competitive in price in the target markets, and all achieve an average installation cost per kW of one third of conventional wind farms, while producing energy in the low range of commercial projects, and even lower for sites with excellent wind resources. 

  • 49.
    Moran, Oliver
    Gotland University, School of Culture, Energy and Environment.
    Value-Cost Appraisal of Wind Energy Applying Portfolio Analysis2012Independent thesis Advanced level (degree of Master (One Year)), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    To meet electricity demand, electric utilities develop portfolio strategies for generation, transmission, and distributions systems. Portfolio strategies combine different assets in a portfolio (getting the average returns from the assets) but the risk or in other words the variability of these returns is expected to cancel each other out, since one asset is likely to be up when another is down. Throughout this analysis the energy consumption for the last 40 years is examined from a Levelised Generation Cost (LGC) and portfolio diversity aspect using certain parameters.

    When monitoring the gas field productions in UK waters the decline in production from the start of the decade can be noticed. Questions have been asked including what will the UK government invest in next? People are often told if they want to receive higher returns from their investment, they should increase the proportion of stocks in their portfolio or change the mix and invest in more aggressive asset/stock combinations. So can the United Kingdom rely on more imports from a perilously volatile market? When the situation is analysed closely and past events are scrutinised, such as when Russia stopped all gas supplies across the Ukraine (which carried about a fifth of the EU's gas needs) and more presently the conflicts in the Middle East which have affected oil prices, the answer is simple. The United Kingdom investing in more imports is akin to telling people to drive 100 miles per hour if they want to get somewhere sooner. While it's possible that they will arrive faster, it also dramatically increases the likelihood that they won't arrive at all. So where does this leave the future of energy consumption in the British Isles? To counteract this problem the government has looked towards wind power, with focus on offshore wind and in June 2011 they announced the largest nuclear programme for a generation with eight new sites having been proposed. The UK however has gained financially from the northern gas fields with calculated CCGTs LCG of £30.31 MWh provideding affordable electricity for its customers during the last decade (Department of Trade and Industry, 2000). With the gas production declining however a move to nuclear with£175.95 LCG seems costly. Onshore wind £28.62 MWh expected return with £40 MWh income generation used and £34.82 Renewables Obligation Certificates (ROCs) shows why developers are constructing wind farms through out the British Isles. The Modern Portfolio Theory (MPT) analysis has also shown the overall economical diversity of fuels since 1970 has improved.

  • 50.
    Moubarak, Roger
    Gotland University, School of Culture, Energy and Environment.
    Wind Speed Prediction using Global and Regional Based Virtual Towers in CFD Simulations2011Independent thesis Advanced level (degree of Master (One Year)), 40 credits / 60 HE creditsStudent thesis
    Abstract [en]

    Wind farm assessment is a costly and time consuming process when it is planned by traditional methods such as a met mast. Therefore, new models have been established and used for the wind farm assessment to ease the process of wind farm planning. These models are Global-regional models which add to cost efficiency and time saving. There are several types of these models in the market that have different accuracy. This thesis discusses and uses in simulations Global – regional model data outputs from European Centre for Medium-Range Weather Forecasts (ECMWF), Weather Research Forecast WRF and ECMWF, which is currently producing ERA-Interim, global reanalysis of the data-rich period since 1989 .The goal of the master's thesis is to see whether it is useful and efficient to use Global – regional weather model data such as the Era Interim Global Reanalysis Model data for wind assessment by comparing it with the real data series (met mast) located in Maglarp, in the south of Sweden.The comparison shows that in that specific area (hindcast) at Maglarp, in the south of Sweden, very promising results for planning a wind farm for a 100m, 120m and 38m heights.

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