Global ETD Search

131	Behavioural reactions of cod (Gadus morhua) and plaice (Pleuronectes platessa) to sound resembling offshore wind turbine noise Müller, Christina 27 February 2008 (has links) Durch die Zunahme von Offshorewindparks wird der anthropogene Lärmpegel im Meer weiter ansteigen. Deshalb ist es notwendig, mögliche negative Effekte von Windturbinenschall auf Fische zu erkennen und zu minimieren. Um mögliche Effekte des Turbinenschalls auf Kabeljau (Gadus morhua) und Scholle (Pleuronectes platessa) zu untersuchen, wurden die Fische in Laborversuchen verschiedenen tiefen Frequenzen und Schallstärken, wie sie von Windturbinen emittiert werden ausgesetzt. Ein ringförmiges Betonversuchsbecken mit 10 Metern Durchmesser wurde mit Schallisolationwänden in verbundene Viertel unterteilt, wodurch im Becken eine Schalldruckdifferenz von 32-52 dB, abhängig von Frequenz und produziertem Schalldruckpegel erzeugt wurde. Die Fische, die sich frei im Becken bewegen und so, wenn sie wollten, den höchsten Schalldruckpegeln ausweichen konnten, wurden monofrequenten Tönen im Frequenzbereich zwischen 25 und 250 Hz in Schalldruckpegeln von 130 und 140 dB re 1 µPa ausgesetzt. Die Position der Fische im Becken wurde in den 24-Stunden-Phasen vor, während und nach Beschallung verglichen und zeigte in den meisten Versuchen während Beschallung signifikant weniger Kabeljau in der Nähe der Schallquelle, als in den Phasen vor und nach Beschallung. Scholle zeigte uneinheitliche Reaktionen, die teilweise auf Meideverhalten, in anderen Versuchen auf Attraktion durch den Schall hindeuteten. Die Ergebnisse lassen wenigstens kurzzeitige, durch Schall verursachte Verteilungsänderungen von Kabeljau in Offshorewindparks erwarten. / The growing number of offshore wind farms will lead to an increase of anthropogenic noise in the sea. Research is therefore necessary to identify and minimize any potentially negative effects of offshore wind turbine noise on fish. To examine the potential impact of offshore wind farm noise emissions on cod (Gadus morhua) and plaice (Pleuronectes platessa), tank experiments were carried out exposing the fishes to different low frequencies at sound levels as emitted by wind turbines An annular concrete tank of 10 m in diameter was divided in connected quarters by sound barriers, so that sound pressure differences of 32 to 52 dB were achieved, depending on frequency and produced sound levels. Pure tones in the frequency range between 25 and 250 Hz were artificially emitted in sound levels of 130 and 140 dB re 1µPa. The experimental fish were free to move around in the tank and therefore could avoid the highest sound levels if they chose to. The location of fish in the 24 hour periods before, during and after sound production were compared and showed significantly lower numbers of cod in the vicinity of the sound source during sound presentation in the majority of the experiments. Reactions of plaice were ambiguous, suggesting both avoidance of, or attraction to the sound. From the results at least short-term changes in distribution of cod related to sound in the vicinity of offshore wind farms could be expected. Schall Verhalten Offshore Windanlagen Fisch Kabeljau Gadus morhua Scholle Pleuronectes platessa Lärm Vermeidung Reaktion Forschung sound offshore wind farm research fish cod Gadus morhua plaice Pleuronectes platessa behavioural reactions noise avoidance 570 Biologie 32 Biologie WR 3200 ddc:570
132	A Comparative Study on Two Offshore Wind Farm Siting Approaches in Sweden / En jämförande studie av två tillvägagångssätt för siting av havsbaserade vindkraftsparker i Sverige Nyberg, Anders, Sundström, Oskar January 2023 (has links) This study aims to explore the ability of a multi-criteria decision making with analytical hierarchy process (MCDM-AHP) model to emulate the results of a cost benefit analysis (CBA) model in the context of offshore wind farm siting within the Swedish exclusive economic zone (EEZ). The research question addressed is whether the MCDM-AHP analysis produces similar results to the CBA analysis. In addition to this, the strengths and weaknesses of each model is explored. The MCDM-AHP model employs the spatial criteria in a more basic manner compared to the CBA model, simplifying the evaluation process while still explaining 89.5% of the variation in the CBA model and defining similar areas as suitable. Thus, it can be concluded that the MCDM-AHP model adequately emulates the CBA model within the context of offshore wind farm siting within the Swedish EEZ. However, it is crucial to note that the two models produce outputs on different scales. While the CBA model provides levelized cost of energy (LCOE) values that can be thresholded for investment viability comparisons, the suitability score generated by the MCDM-AHP model remains a relative and arbitrary score within the model. Both models entail uncertainties, limiting their usage beyond making general assumptions or identifying areas of interest. The findings reveal that the CBA model demonstrates greater robustness when confronted with changes in spatial input parameters compared to the MCDM-AHP model. This discrepancy is attributed to the iterative computation process and consideration of flat cost inputs in the CBA model, whereas the MCDM-AHP model represents a linear combination of various spatial parameters. However, the calculated LCOE values in the CBA model are highly sensitive to changes in modeling assumptions regarding external parameters, resulting in significant linear variations. The LCOE values obtained from the CBA model baseline case fall within a range of 52.1 - 98.9 EUR/MWh, which aligns with similar studies, validating the CBA model. Nonetheless, caution should be exercised when considering these results as an accurate representation of the real world due to inherent uncertainties in cost inputs and the LCOE measure. The strengths of the MCDM-AHP model lie in its robustness when the order of relative importance remains stable for key spatial evaluators. It is sensitive to significant changes in water depth and wind speed, which heavily influence its output. The model's simplicity allows for a quick overview of the problem, but it requires assumptions that introduce uncertainties. Validation of the MCDM-AHP model using existing and planned offshore wind farms within the Swedish EEZ was possible but limited by the arbitrary scale and limited validation areas. The comparison between the two models could be enhanced with more comprehensive spatial and economic data for an in-depth CBA model, which could serve as a ground truth for the MCDM-AHP model. Nevertheless, the comparison made in this study considers the CBA model to be closer to the truth, acknowledging the underlying assumptions that should be considered during evaluation. In conclusion, within the context of offshore wind farm siting, the MCDM-AHP model produces outputs that are similar to the CBA model. Multi-Criteria Decision Making Analytical Hierarchy Process Cost Benefit Analysis Offshore Wind Farm Siting Swedish Exclusive Economic Zone Levelized Cost of Energy GIS Sweden Renewable Energy Offshore Wind Energy Spatial Model Comparison Multikriterieanalys Analytisk hierarkiprocess Kostnadsintäktsanalys Siting av havsbaserade vindkraftverk Sveriges exklusiva ekonomiska zon Nivåkostnad för energi GIS Sverige Förnybar energi Havsbaserad vindkraft Jämförelse av spatiala modeller Multi-Criteria Decision Making Analytical Hierarchy Process Cost Benefit Analysis Economics Nationalekonomi
133	Analyse de la compensation écologique comme instrument d'internalisation et de lutte contre l'érosion de la biodiversité marine : illustration par l'éolien en mer / Analysis of biodiversity offsetting as an internalization instrument to halt the erosion of marine biodiversity : illustration by offshore wind farms Bas, Adeline 28 February 2017 (has links) L’installation des énergies marines renouvelables s’effectue dans le respect des législations environnementales françaises. La séquence Eviter-Réduire-Compenser (ERC) est ainsi appliquée pour aboutir à une non-perte nette de biodiversité. L’objectif de la thèse est de questionner l’efficacité de cette séquence, et plus particulièrement celle de la compensation écologique, en tant qu’instrument d’internalisation et de lutte contre l’érosion de la biodiversité marine. Une approche empirique qualitative a ainsi été mise en oeuvre pour (i) identifier les facteurs écologiques et sociétaux ainsi que leurs caractéristiques théoriques qui doivent permettre à la compensation d’atteindre l’objectif de non-perte nette de biodiversité ; et (ii) contrôler si ces conditions sont vérifiées en pratique dans le cas de l’éolien en mer en Europe et en France. L’analyse met en avant les enjeux juridiques, institutionnels, méthodologiques et sociétaux à relever pour permettre à la compensation écologique d’atteindre son objectif. Sur la base de ce constat, une évaluation multicritères est proposée afin de renforcer les étapes d’évitement et de réduction pour finalement mieux définir les besoins de compensation écologique en mer. L’analyse met par ailleurs en évidence un glissement d’une compensation basée sur une équivalence écologique stricte à une compensation fondée sur une équivalence écologique relâchée. Les actions de compensation tendent à être plus généralistes et/ou davantage dirigées vers les services écosystémiques que sur les composantes des écosystèmes. Associées aux mesures d’accompagnement, elles peuvent contribuer à faciliter l’acceptabilité sociale d’un projet d’aménagement. / The installation of marine renewable energies is carried out in compliance with French environmental legislation. The mitigation hierarchy is thus applied to achieve an objective of no net loss of biodiversity. This thesis aims at questioning the effectiveness of the mitigation hierarchy and more specifically biodiversity offsetting as an internalization instrument to halt the erosion of marine biodiversity. We use a qualitative empirical approach to (i) identify the ecological and societal factors as well as their theoretical characteristics that are supposed to enable the offsets achieving the objective of no net loss of biodiversity; and (ii) control whether these conditions are verified in practice for the case of offshore wind farms in Europe and France. The analysis highlights the legal, institutional, methodological and societal issues to be addressed in order to enable biodiversity offsetting to achieve the no net loss priority. On the basis of this observation, a multi-criteria assessment is carried out to reinforce the avoidance and reduction steps of the mitigation hierarchy in order to better define offsetting needs. Ultimately, the analysis shows a shift in biodiversity offsetting based on a strict ecological equivalence to a biodiversity offsetting based on a released ecological equivalence. Offsetting actions tend to be more generalist and / or more directed to ecosystem services than to ecosystem components. Associated with accompanying measures, offsetting actions can help to increase the social acceptability of a development project. Compensation écologique Séquence Eviter-Réduire-Compenser Energies marines renouvelables Eolien en mer Acceptabilité sociale Milieu marin Méthodes de dimensionnement Non-perte nette de biodiversité Biodiversity offsets Mitigation hierarchy Marine renewable energy Offshore wind farm Social acceptability Marine ecosystems Losses and gains assessment methodology No net loss of biodiversity 338.927
134	Offshore Wind Energy Permitting Processes in the European Union : An examination of Danish, German, Scottish and Swedish offshore permitting processes and case study of acoustic impact on marine mammals / Havsbaserad vindkraft tillståndsprocesser inom Europeiska union : Undersökning av dansk, tysk, skottsk och svensk havsbaserad tillståndsprocesser och en fallstudie av akustiskpåverkan på marin däggdjur Jack, Truce Major January 2022 (has links) The permitting process is an integral part of the successful expansion of offshore wind and renewable energy in the European Union. Many permit process studies, to date, have focused on limited methods and criteria and have been a comparison of two countries. This thesis was written in collaboration with a steering group’s work on an updated marine synthesis report in the Swedish Energy Agency and Swedish Environmental Protection Agency’s joint research programme, Vindval. It compares the permitting process and its effectiveness in 4 EU countries (Germany, Denmark, Scotland, and Sweden) with special emphasis on the acoustic impacts of wind turbine construction. 6 Key criteria that determine the outcome of a successful permit application were analysed: a) permit process maps b) quantity of actors c) consultation times d) ecological and environmental impact e) “planning vs permitting” and e) handling of acoustic impacts on marine mammals. Sweden’s process was found to be the most cumbersome and ineffective among the 4 countries. Germany, Denmark, and Scotland have streamline processes, in part due to the successful employment of a ‘one-stop-shop’ mechanism. It is recommended that Sweden create a similar, singular, and centralized ‘one-stop-shop’ authority that has the power to dictate permitting processes. If the country is to meet its goal of 100% renewable energy by 2040, permitting policy should include: flexible permitting for rapidly changing technology, endorsement of continuous dialog between authorities, a limit on consultation time, the removal or amendment of municipal vetoes, and have clear demarcation of worthwhile explorable zones reserved for offshore wind. Permitting process wind power offshore wind power acoustic impact environmental impact assessment marine mammals physical planning ecology offshore EIA environmental management juridiska förutsättningar permit tillstånd tillståndsprocess vindkraft miljöledning ekologi energisystem miljövetenskap påverkan bedömning marin däggdjur Environmental Sciences Miljövetenskap Ecology Ekologi Environmental Management Miljöledning Energy Systems Energisystem Law and Society Juridik och samhälle
135	Hydrogen Production and Storage Optimization based on Technical and Financial Conditions : A study of hydrogen strategies focusing on demand and integration of wind power. / Optimering av vätgasproduktion och lagring utifrån tekniska och ekonomiska förutsättningar : En studie av vätgasstrategier med fokus på efterfrågan och integration av vindkraft. Langels, Hanna, Syrjä, Oskar January 2021 (has links) There has recently been an increased interest in hydrogen, both as a solution for seasonal energy storage but also for implementations in various industries and as fuel for vehicles. The transition to a society less dependent on fossil fuels highlights the need for new solutions where hydrogen is predicted to play a key role. This project aims to investigate technical and economic outcomes of different strategies for production and storage of hydrogen based on hydrogen demand and source of electricity. This is done by simulating the operation of different systems over a year, mapping the storage level, the source of electricity, and calculating the levelized cost of hydrogen (LCOH). The study examines two main cases. The first case is a system integrated with offshore wind power for production of hydrogen to fuel the operations in the industrial port Gävle Hamn. The second case examines a system for independent refueling stations where two locations with different electricity prices and traffic flows are analyzed. Factors such as demand, electricity prices, and component costs are investigated through simulating cases as well as a sensitivity analysis. Future potential sources of income are also analyzed and discussed. The results show that using an alkaline electrolyzer (AEL) achieves the lowest LCOH while PEM electrolyzer is more flexible in its operation which enables the system to utilize more electricity from the offshore wind power. When the cost of wind electricity exceeds the average electricity price on the grid, a higher share of wind electricity relative to electricity from the grid being utilized in the production results in a higher LCOH. The optimal design of the storage depends on the demand, where using vessels above ground is the most beneficial option for smaller systems and larger systems benefit financially from using a lined rock cavern (LRC). Hence, the optimal design of a system depends on the demand, electricity source, and ultimately on the purpose of the system. The results show great potential for future implementation of hydrogen systems integrated with wind power. Considering the increased share of wind electricity in the energy system and the expected growth of the hydrogen market, these are results worth acknowledging in future projects. Hydrogen hydrogen energy system hydrogen production hydrogen storage large-scale storage underground storage vessels LRC hydrogen application hydrogen strategies hydrogen transition offshore wind energy electricity grid electricity price volatile electricity prices renewable energy hydrogen refueling station hydrogen port green hydrogen hydrogen trucks hydrogen forklifts fuel cells electrolysis alkaline electrolyzer PEM electrolyzer levelized cost of hydrogen LCOH Vätgas vätgassystem vätgasproduktion vätgaslagring storskalig vätgaslagring bergrum vätgasapplikationer vätgasstrategi vätgasomställning grön omställning havsbaserad vindkraft volatila elpriser elnätet förnybar energi vätgastankstation vätgasmack vätgashamn grön vätgas vätgaslastbilar vätgastruckar bränsleceller elektrolys alkalisk elektrolysör PEM elektrolysör Elektroteknik och elektronik
136	Computational Methods for Renewable Energies: A Multi-Scale Perspective Diego Renan Aguilar Alfaro (19195102) 23 July 2024 (has links) <p dir="ltr">The urgent global shift towards decarbonization necessitates the development of robust frameworks to navigate the complex technological, financial, and regulatory challenges emerging in the clean energy transition. Furthermore, the increased adoption of renewable energy sources (RES) is correlated to the exponential growth in weather data research over the last few years. This circular relationship, where big data drives renewable growth, which feeds back the data pipeline, serves as the primary focus of this study: the development of computational tools across diverse spatial and temporal scales for the optimal design and operation of renewable energy-based systems. Two scales are considered, differentiated by their primary objectives and techniques used. </p><p dir="ltr"> In the first one, the integration of probabilistic forecasts into the operations of RES microgrids (MGs) is studied in detail. It is revealed that longer scheduling horizons can reduce dispatch costs but at the expense of forecast accuracy due to increased prediction accuracy decay (PAD). To address this, a novel method that determines how to split the time horizon into timeblocks to minimize dispatch costs and maximize forecast accuracy is proposed. This forms the basis of an optimal rolling horizon strategy (ORoHS) which schedules distributed energy resources over varying prediction/execution horizons. Results offer Pareto-optimal fronts, showing the trade-offs between cost and accuracy at varying confidence levels. Solar power proved more cost-effective than wind power due to lower variability, despite wind’s higher energy output. The ORoHS strategy outperformed common scheduling methods. In the case study, it achieved a cost of \$4.68 compared to \$9.89 (greedy policy) and \$9.37 (two-hour RoHS). The second study proposes the Caribbean Energy Corridor (CEC) project, a novel, ambitious initiative that aims to achieve total grid connectivity between the Caribbean islands. The analysis makes use of thorough data procedures and optimization methods for the resource assessment and design tasks needed to build such an infrastructure. Renewable energy potentials are quantified under different temporal and spatial coverages to maximize usage. Prioritizing offshore wind development, the CEC’s could significantly surpass anticipated growth in energy demand, with an estimated installed capacity of 34 GW of clean energy upon completion. The corridor is modeled as an HVDC grid with 32 nodes and 31 links. Underwater transmission is optimized with a Submarine-Cable-Dynamic-Programming (SCDP) algorithm that determines the best routes across the bathymetry of the region. It is found that the levelized cost of electricity remains on the low end at \$0.11/kWh, despite high initial capital investments. Projected savings reach \$ 100 billion when compared with ”business-as-usual” scenarios and the current social cost of carbon. Furthermore, this infrastructure has the potential to create around 50,000 jobs in construction, policy, and research within the coming decades, while simultaneously establishing a robust and sustainable energy-water nexus in the region. Finally, the broader implications of these works are explored, highlighting their potential to address global challenges such as energy accessibility, prosperity in conflict zones, and sharing these discoveries with the upcoming generations.</p> Electrical energy storage Photovoltaic power systems Evolutionary computation Modelling and simulation Planning and decision making Satisfiability and optimisation Data engineering and data science Neural networks Reinforcement learning Renewable Energies Optimization Power Systems Microgrids Energy Corridors Machine Learning Artificial Intelligence Robust Optimization Genetic Algorithm Mixed Integer Linear Programming Multi-objective Optimization Economic Dispatch Unit Commitment Wind Energy Solar Energy Caribbean Energy Corridor HVDC Submarine Power Transmission Dynamic Programming Wandering Salesman Problem Big Data Offshore Wind Battery Energy Storage System

Page generated in 0.0547 seconds