The increasing demand for sustainable energy is one of the driving forces behind the increasing use of wind power by means of wind-turbines in electric power systems. Modern wind turbines commonly employ variable-speed-generator technology associated with a power-electronic converter as part of the grid connection. A drawback of the use of power electronics is the presence of harmonic emissions. Consequently a systematic study on distortion from wind power installations is needed; this holds for individual wind turbines as well for complete installations.In the work, measurements and analysis of harmonic emissions were performed on a number of wind-turbines in several wind parks in Northern Sweden. The measurements on the individual wind turbines reveal that the harmonic emissions are different from each other, even for different turbines from the same manufacturer. However in general the characteristic harmonics dominate the harmonic emissions. Furthermore, a long-term measurement shows that the dominant frequencies in the emission change with time.The total emission from a wind park into the public grid is determined by the emission from individual turbines and by the properties of the wind park. To study the impact of the wind park on the propagation a ``transfer function'' method has been introduced, and applied by means of calculation and simulation. The method is based on a mathematical model that predicts the harmonic propagation from the wind turbines to the public grid in the frequency range up to 50 kHz. Applying the model to three example parks reveals that, the amplitudes at the resonance frequency are strongly dependent on the resistance of both underground cables and transformer, especially at high frequencies. In other words, the higher order harmonics are damped a lot.In conclusion, wind park harmonic emissions into the public grid are due to the combination of emission from individual wind turbines and the propagation through the collection grid.

Renewable energy, including offshore wind power, is expected to play a significant role in mitigating climate change and meeting a growing demand on electricity. Fiji, a Small Island Developing Nation in the South Pacific, needs large quantities of additional renewable energy to achieve its NDC goals and has good natural resources for offshore wind power. The purpose of the study is to analyse the technical potential for fixed and floating offshore wind power, identify the most suitable site (s), perform economic feasibility analysesfor different-sized offshore wind farms and determine possible emission reductions from offsetting electricity generation based on fossil fuels. The objectives are achieved through a literature study, interviews, a GIS-based multi-criteria site suitability analysis and feasibility calculations. In the study it was concluded that there is great potential for offshore wind power in Fiji. There are large areas with technical potential for fixed and floating offshore wind power and the most suitable sites, both located in the Bligh waters, have average wind speeds of 8.6 m/s and 8.5 m/s. The potential for offshore wind power was concluded to be large enough for Fiji’s needs, economically feasible and potentially competitive to invest in. The simple payback time would be approximately 13.5 years and the cost of electricity would be 0.13 USD/kWh, which is lower than the feed-in tariff for Fiji’s national grid at 0.15 USD/kWh. Different-sized offshore wind farms and its possible emission reductions could contribute with between 12-37% of Fiji’s NDC goal to reduce emissions from the energy sector by 30% compared to a business as usual scenario as well as contribute to have 99% renewable grid-connected electricity generation by 2030. However, during the study, it was concluded an implementation of offshore wind power in Fiji would require large investments, large capacities of energy storage, frequency regulating services and there are potential environmental and social impacts have to be taken into consideration. There is also a need for further research on how to cyclone-proof offshore wind farms in Fiji. / Förnybar energi, inklusive havsbaserad vindkraft, förväntas spela en avgörande roll för att minska klimatförändringarna och för att möta en ökande efterfrågan på elektricitet. Fiji, en liten önation i Stilla havet, behöver stora mängder ytterligare förnybar energi för att nå sina NDC mål och har bra naturresurser för havsbaserad vindkraft. Syftet med studien är att analysera den tekniska potentialen för fixerad och flytande havsbaserad vindkraft, identifiera de mest lämpliga platserna, utföra ekonomiska lönsamhetsanalyser för olika stora havsbaserade vindkraftsparker och avgöra möjliga utsläppsminskningar genom att avsätta elproduktion baserad på fossila bränslen. Målen uppfylls genom en litteraturstudie, intervjuer, GIS-baserad multikriterie platslämplighetsanalys och genomförbarhetsberäkningar. I studien drogs slutsatsen att det finns stor potential för havsbaserad vindkraft i Fiji. Det finns stora områden med teknisk potential för fixerad och flytande havsbaserad vindkraft och de mest lämpliga platserna, båda belägna i Bligh waters, har genomsnittliga vindhastigheter på 8.6 m/s och 8.5 m/s. Potentialen för havsbaserad vindkraft bedöms vara stor nof för Fijis behov, ekonomsikt genomförbart och potentiellt konkurrenskraftigt att investera i. Återbetalningstiden bedöms vara ungeför 13.5 år och elektricitetskostnaden 0.13 USD/kWh, vilket är lägre än inmatningstaxan till Fijis nationella elnät som är på 0.15 USD/kWh. De 12-37% av Fijis mål om att minska utsläppen från energisektorn med 30% jämfört med ett business as usual scenario liksom bidra till att ha 99% förnybar elnätsansluten elgeneration till 2030. Men, i studien drog också slutsatsen att en implementering av havsbaserad vindkraft i Fiji skulle kräva stora investeringar, stora mängder energilagring, frekvensreglerande tjänster och det finns potentiella miljömässiga och sociala effekter som måste tas i hänsyn. Det finns också behov av ytterligare forskning om hur man kan cyklon-säkra havsbaserade vindkraftsparker i Fiji.

As part of the transition towards a fully sustainable energy system, green hydrogen shows great potential to decarbonise several hard-to-abate sectors. To provide the fossil-free electricity required for electrolysis, offshore wind power has emerged as a suggested option. In this report, four scenarios using different electrolyser placements and technologies are compared and applied in a 30-year case study considering a 1 GW offshore wind farm in the Baltic Sea. The scenarios are evaluated through the optimisation of electrolyser capacities, full system modelling and simulation, a techno-economic assessment, as well as a literature review of technological readiness, safety aspects and operational considerations. It is shown that a range of installed capacities offers only slight differences in levelised costs and that the optimal sizes to a large part depend on future electrolyser cost developments. A 1:1 sizing ratio between electrolyser capacity and maximum available power is not suggested for any of the studied configurations. Further, the simulations indicate that electrolyser inefficiencies constitute 63.2–68.5% of the total energy losses. Power transmission losses are relatively small due to the short transmission distance, while the power demands of several subsystems are nearly insignificant. Onshore H2 production using an alkaline electrolyser system is highlighted, offering the highest system efficiency and largest hydrogen production, at 55.93% and 2.23 Mton, respectively. This setup is further shown to be the most cost-efficient, offering a levelised cost of hydrogen at 3.15 €/kgH2. However, obstacles in the form of social and environmental concerns and regulations are seemingly larger compared to the scenarios using offshore electrolysis. Further, rapid future cost developments for electrolysers are likely to strengthen the case for offshore and PEM electrolyser configurations. A range of research opportunities are highlighted to fill the identified knowledge gaps and enable further insights. / Como parte de la transicion hacia un sistema energético totalmente sostenible, el hidrógeno verde muestra un gran potencial para descarbonizar varios sectores en los que es difíciles de conseguir. La energía eólica marina ha surgido como una opción para suministrar la electricidad libre de fósiles necesaria para la electrólisis. En este informe se comparan y aplican cuatro escenarios que utilizan diferentes ubicaciones y tecnologías de electrolizadores en un estudio de caso a 30 aoñs que considera un parque eólico marino de 1 GW en el Mar Báltico. Los escenarios se evalúan mediante una optimización de la capacidad de los electrolizadores, la modelización y simulación de todo el sistema, una revisión bibliográfica de la disponibilidad tecnológica, teniendo en cuenta los aspectos de seguridad y las consideraciones operativas. Se demuestra que una gama de capacidades instaladas ofrece sólo ligeras diferencias en los costes nivelados y que los tamaños óptimos dependen en gran medida de la evolución futura de los costes de los electrolizadores. No se recomienda una relación de tamaño de 1:1 entre entre la capacidad del electrolizador y la potencia máxima disponible. Además, las simulaciones indican que las ineficiencias del electrolizador constituyen entre el 63,2% y el 68,5% de las pérdidas totales de energía. Las pérdidas de transmisión de energía son relativamente pequeñas debido a la corta distancia de transmisión, mientras que las demandas de energía de varios subsistemas son casi insignificantes. Destaca la producción de H2 en tierra utilizando un sistema de electrolizador alcalino, que ofrece la mayor eficiencia del sistema y la mayor producción de hidrógeno, con un 55,93% y 2,23 Mton respectivamente. Además, este sistema es el más rentable, con un coste nivelado del hidrógeno de 3,15 €/kgH2. Sin embargo, los obstáculos sociales, medioambientales y normativos parecen ser mayores que en el caso de la electrólisis en alta mar. Además, es probable que la rápida evolución de los costes de los electrolizadores refuerce las configuraciones de electrolizadores marinos y PEM. Se destacan en el documento una serie de oportunidades de investigación con el fin de completar el estado del arte identificado.

As part of the transition towards a fully sustainable energy system, green hydrogen shows great potential to decarbonise several hard-to-abate sectors. To provide the fossil-free electricity required for electrolysis, offshore wind power has emerged as a suggested option. In this report, four scenarios using different electrolyser placements and technologies are compared and applied in a 30-year case study considering a 1 GW offshore wind farm in the Baltic Sea. The scenarios are evaluated through the optimisation of electrolyser capacities, full system modelling and simulation, a techno-economic assessment, as well as a literature review of technological readiness, safety aspects and operational considerations. It is shown that a range of installed capacities offers only slight differences in levelised costs and that the optimal sizes to a large part depend on future electrolyser cost developments. A 1:1 sizing ratio between electrolyser capacity and maximum available power is not suggested for any of the studied configurations. Further, the simulations indicate that electrolyser inefficiencies constitute 63.2–68.5% of the total energylosses. Power transmission losses are relatively small due to the short transmission distance, while the power demands of several subsystems are nearly insignificant. Onshore H2 production using an alkaline electrolyser system is highlighted, offering the highest system efficiency and largest hydrogen production, at 55.93% and 2.23 Mton, respectively. This setup is further shown to be the most cost-efficient, offering a levelised cost of hydrogen at 3.15 €/kgH2. However, obstacles in the form of social and environmental concerns and regulations are seemingly larger compared to the scenarios using offshore electrolysis. Further, rapid future cost developments for electrolysers are likely to strengthen the case for offshore and PEM electrolyser configurations. A range of research opportunities are highlighted to fill the identified knowledge gaps and enable further insights. / Como parte de la transición hacia un sistema energético totalmente sostenible, el hidrógeno verde muestra un gran potencial para descarbonizar varios sectores en los que es difíciles de conseguir. La energía eólica marina ha surgido como una opción para suministrar la electricidad libre de fósiles necesaria para la electrólisis. En este informe se comparan y aplican cuatro escenarios que utilizan diferentes ubicaciones y tecnologías de electrolizadores en un estudio de caso a 30 años que considera un parque eólico marino de 1 GW en el Mar Báltico. Los escenarios se evalúan mediante una optimización de la capacidad de los electrolizadores, la modelización y simulación de todo el sistema, una revisión bibliográfica de la disponibilidad tecnológica, teniendo en cuenta los aspectos de seguridad y las consideraciones operativas. Se demuestra que una gama de capacidades instaladas ofrece sólo ligeras diferencias en los costes nivelados y que los tamaños óptimos dependen en gran medida de la evolución futura de los costes de los electrolizadores. No se recomienda una relación de tamaño de 1:1 entre entre la capacidad del electrolizador y la potencia máxima disponible. Además, las simulaciones indican que las ineficiencias del electrolizador constituyen entre el 63,2% y el 68,5% de las pérdidas totales de energía. Las pérdidas de transmisión de energía son relativamente pequeñas debido a la corta distancia de transmisión, mientras que las demandas de energía de varios subsistemas son casi insignificantes. Destaca la producción de H2 en tierra utilizando un sistema de electrolizador alcalino, que ofrece la mayor eficiencia del sistema y la mayor producción de hidrógeno, con un 55,93% y 2,23 Mton respectivamente. Además, este sistema es el más rentable, con un coste nivelado del hidrógeno de 3,15 €/kgH2. Sin embargo, los obstáculos sociales, medioambientales y normativos parecen ser mayores que en el caso de la electrólisis en alta mar. Además, es probable que la rápida evolución de los costes de los electrolizadores refuerce las configuraciones de electrolizadores marinos y PEM. Se destacan en el documento una serie de oportunidades de investigacin ócon el fin de completar el estado del arte identificado.

Sustainable Destination Development implies reaching the 17 SDGs at a destination level. Climate crisis is arguably the primary challenge faced by destinations today. It is now commonly accepted that the crisis is primarily caused due to the burning of fossil fuels while converting it into energy. Therefore, decarbonization of the energy sector appears to be a viable way to eliminate the crisis. This ensued the installation of unprecedented amounts of renewable energy facilities in the last two decades, especially in Europe. As such onshore wind power is at the forefront of this trend and is projected to be the primary renewable source of electricity in Europe in foreseeable future. However, substituting fossil fuels by the renewable energy sources such as onshore wind power requires vast land areas, and as argued by many, may undermine biodiversity conservation – an equally urgent matter to be addressed by destinations. This is because land-use change is identified as the foremost cause of the biodiversity loss globally. Thus, this study was aimed to elucidate the ‘green-green paradox’ (i.e., jeopardizing biodiversity while combating climate crisis) using a qualitative research methodology. The main research questions were intended to reveal current best practices of dealing with the challenge, identify main barriers, and suggest solutions for a better practice in the future. Data was collected through semi-structured expert interviews, and the results were reported using thematic analysis. The study found that the current best practise of addressing the biodiversity challenge is via the Mitigation Hierarchy framework – a regulatory tool intended at safeguarding biodiversity while developing infrastructure projects. Simultaneously, the weak implementation of the hierarchy in practice was identified as the primary barrier for harmonious wind power – biodiversity relationship. The huge knowledge gap in understanding the depth of impacts, lack of uniform methodologies to measure and account for them, and the lack of collaboration and communication between stakeholders were identified as the main factors that impede operationalization of the framework. A need for more stricter and better implemented regulations was an important emergent theme throughout the results that was deemed to potentially be the defining factor in addressing the mentioned impediments.

Quang Ninh province, Vietnam has a rich wind power resources. This type of energy will be soon utilized for generating power to supply all industrial sites including mining corporations. Because of geological characteristics, wind power stations are located near the 6kV grid of mining areas, therefore it needs to make the analysis about the connection ability of wind power generators to the grids. The paper presents the connection model of a wind turbine and 6kV grids. Based on this model, the simulations of system’s possible operating mode are implemented. The conclusions about the suitable operating modes of wind turbine are pointed out to give the operators and grid managers a general observation for the possibility of connecting a wind turbine to 6kV grid / Tỉnh Quảng Ninh là một trong những địa phương giàu tiềm năng về năng lượng gió. Theo phân tích, loại năng lượng này sẽ sớm được đưa vào cung cấp điện năng cho các khu công nghiệp trong đó có các công ty than. Do đặc thù địa lý, các trạm phát phong năng được đặt khá gần các lưới điện 6kV của mỏ, vì thế cần tiến hành phân tích khả năng kết nối trực tiếp các máy phát điện gió với lưới điện này. Bài báo giới thiệu mô hình kết nối máy phát điện gió với lưới 6kV. Các mô phỏng về các chế độ vận hành có thể có của lưới cũng được thực hiện. Các kết luận về chế độ vận hành thích hợp của tua bin gió được đúc rút để giúp người vận hành, các nhà quản lý lưới điện có được cái nhìn tổng quan về khả năng kết nối tua bin gió với lưới điện 6kV.

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Transformers can be described as ’slumbering giants’ in the electric power system. This marks transformers to be big and expensive parts of equipment. Calling them slumbering refers to the unused capacity in many of them. Dynamic Transformer Rating (DTR) is a concept to utilize this potential and wind power connected transformers have been identified as a well-fitting application due to the naturally limited capacity factor and the correlation of low ambient temperature and high wind speeds. Previous scientific work and a small number of applied projects show the feasibility and benefits of combining DTR and wind power. Wind power forecasting is a standard procedure for dispatch planning and electricity trading. This thesis project aims at combining both subjects and focuses on providing and analyzing a forecasting tool. At various forecasting steps Machine-Learning (ML) approaches are tested and evaluated. The developed tool is designed for and tested on a case study comprising an existing wind farm and transformer. It is shown that in many, but not all cases an overheating (exceeding of the Hot Spot Temperature (HST) limit) can be predicted. Applying DTR adds a level of uncertainty to wind power forecasts since not only the wind power but also the transformer capacity must be predicted. In this project however the wind power forecast is identified as the main source of uncertainty. / Transformatorer kan beskrivas som ‚sovande jättar‘ i det elektriska systemet eftersom transformatorer karakteriseras som stor och kostsam utrustning. Att kalla dem sovande hänvisar till den oanvända kapaciteten som finns i många. Dynamic Transformer Rating (DTR) är ett koncept för att använda denna potential och transformatorer kopplade till vindkraftsanläggningar blev utnämnd som en passande tillämpning på grund av deras begränsade kapacitetsfaktor och korrelationen mellan låga temperaturer och höga vindhastigheter. Tidigare vetenskapligt arbete och ett fåtal realiserade projekt visar genomförbarhet och fördelarna med kombinationen av DTR och vindkraft. Vindkraftsprognoser är något man vanligen använder inom driftplanering av vindkraftverk och elhandel. Detta examensarbete har som mål att kombinera båda metoderna och fokuserar på att framställa och analysera ett prognosverktyg. Olika tillvägagångssätt testas och evalueras vid de olika stegen som tas. Verktyget är skapat och testat på en fallstudie som i sig är baserad på data från existerande vindkraftverk och transformatorer. Det visar sig att man kan förutsäga överskridandet av Hot spot temperature (HST) vid många tillfällen men inte alla. Tillämpning av DTR lägger till osäkerheter till vinkraftsprognoser för att både kapaciteten på vindkraftverk och på transformatorn måste förutsägas. I detta projekt visade sig vinkraftsprognosen vara den största källan till osäkerhet.