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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
261

The Issue of Trust in Swedish Wind Power Planning : A case study of the wind power project in Markbygden, Sweden / Frågan om förtroendet inom svensk vindkraftsplanering : En fallstudie av vindkraftsprojektet i Markbygden

Johansson, Magnus January 2011 (has links)
Sweden has decided that by the year of 2020, 30 TWh of energy should come from wind power turbines. The wind power developer Svevind AB is planning to build Europe’s largest wind power park in the area of Markbygden in the municipality of Piteå. Thus, the wind power park will be the largest in Swedish history and will bring with it technical and strategic challenges. The main aim for this thesis is to analyze how different factors affect the level of trust in a wind power planning project and doing so through targeting three focus areas; legislation, communication and agreements. The study is based upon case study methodology and where interviews, document studies, literature studies and a media review is used as methods. The theoretical framework is built around communication, power and the privatization of planning. The case study investigates two parallel processes that the planned wind power park in Markbygden has undertaken and what actors that has been most active. The conclusions that can be drawn from the study are that the trust between actors is built up around strategic choices and strategic actions. The means that it can be distinguished distrust towards the purpose behind the actor’s choice of communication and action. Further, the current legislation together with the more and more privatized spatial planning, are two major causes to the that it is increasingly hard to determine who that actually is in charge of planning. This may in turn lead to a lack of trust and understanding towards planning. / Sverige har beslutat att införa en planeringsram för vindkraftsutbyggnaden som innebär att 30 TWh av Sveriges energi skall utvinnas ur vindkraftsverk. Företaget Svevind AB planerar att bygga Europas största vindkraftspark i området Markbygden i Piteå kommun. Vindparken kommer således att bli det största vindkraftsprojektet i Svensk historia vilket medför utmaningar tekniskt men även för den strategiska planeringen. Uppsatsen har till syfte att undersöka huruvida vilka faktor som kan påverka förtroendet som aktörer har mellan varandra och medborgarnas förtroende till samhällsplanering. Studien har begränsats till att fokusera på hur gällande lagstiftning, kommunikation och överenskommelser kan påverka förtroendekapitalet inom samhällsplaneringen. Studien är baserad på en fallstudie där metoderna som ligger till grund är intervjuer, litteraturstudier, dokumentstudier samt mediastudier. Den teoretiska ramen för studien bygger del på teorier kring kommunikativa planeringsteorier, makt och post-politik. Fallstudien är en genomgång av de processer som den planerade vindkraftsparken i Markbygden har genomgått samt vilka aktörer som har varit inblandade. De slutsatser som kan dras av denna studie är att förtroendet mellan aktörerna är byggt på strategiska val. Detta innebär att det kan skönjas en misstro till syftet bakom en aktörs handlingar och kommunikation. Den gällande svenska lagstiftningen samt den allt mer privatiserade samhällsplaneringen är två starkt bidragande faktorer till att det är svårt att urskilja vem som de facto är beslutsfattaren inom dagens samhällsplanering.
262

Modeling, Control and Maximum Power Point Tracking (MPPT) of Doubly-fed Induction Generator (DFIG) Wind Power System

Zou, Yu 24 July 2012 (has links)
No description available.
263

Tidal park within offshore wind parks : An analysis for the potential use of tidal kites within the Aberdeen offshore wind farm

Merkai, Christina January 2018 (has links)
Offshore wind has proved to be one of the most reliable and clean energy sources over the last few years. The industry has experienced a significant growth, with an increase of 101% only in 2017 compared to 2016. This raises the importance of the need for more secure power supply systems, which can be used for controlling the offshore farms during disconnections from the main grid. Nowadays, diesel generators are being used to feed auxiliary services of the offshore wind turbines in situations of emergency. However, as the marine renewable energy industry evolves, tidal energy parks have the potential to replace diesel generators and provide a more sustainable and eco-friendly solution for a long-term auxiliary power system. Moreover, they have the potential to produce extra power, which can be either stored for future use or linked directly to distribution. This report demonstrates a technical, financial and environmental assessment of a potential tidal park within an offshore wind park. Comparison with alternative sources for emergency power supply is also performed. Three alternative locations with high wind speeds and large tidal resource around the UK coast and four different groups of tidal devices are evaluated and compared for the implementation of this solution with the use of ArcGIS maps and other accessible marine data. The Aberdeen wind farm and the tidal kites are selected for further investigation and cost analysis. Seven tidal kites with average power 700 kW and rated power 3.5 MW can provide adequate power to the offshore wind farm for three months without grid connection, whereas they can also provide excess of energy on daily basis when grid disconnection does not occur. The total cost for the project would be approximately 301.6 MSEK. Due to the current renewable energy market, the project is not feasible without high investment risks. However, this study should be evaluated again in the near future when the cost of the tidal device will be further decreased. / Havsbaserad vind har visat sig vara en av de mest tillförlitliga och rena energikällorna under senare år. Inom denna industri har en betydande tillväxt skett, med en ökning med 101% år 2017 jämfört med 2016. Detta relaterar till behovet av säkra elförsörjningssystem, som kan användas för att styra havsbaserade vindraftverksparker under urkoppling från huvudnätet. Numera används dieselgeneratorer som reservkälla till havsvindkraftverk i nödsituationer. Men när den marina förnybara energiindustrin utvecklas, har tidvattenkraftverk potential att ersätta dieselgeneratorer och ge ett mer hållbar och miljövänlig långtidslösning. Dessutom har de potential att producera extra el, som antingen kan lagras för framtida användning eller kopplas direkt till distributionsnätet. Denna rapport erbjuder en teknisk, finansiell och miljömässig bedömning av en potentiell tidvattenkraftverkspark kopplad till en havsvindpark. Jämförelse med alternativa källor för strömförsörjning genomförs också. Tre alternativa platser med hög vindstyrka och stora tidvattenresurser längs Storbritanniens kust och fyra olika grupper av tidvattenanordningar utvärderas och jämförs med hjälp av kartor och andra tillgängliga marina data. Aberdeen vindkraftpark och tidvattendrakar väljs för ytterligare undersökning och kostnadsanalys. Sju tidvattendrakar med genomsnittlig effekt på 700 kW och nominell effekt 3,5 MW kan ge tillräckligt med el till havsvindkraftverk i tre månader utan nätförbindelse, medan de också kan ge överflöd av energi dagligen när strömavbrott inte förekommer. Den totala kostnaden för projektet skulle vara cirka 301,6 MSEK. På grund av läget idag på elmarknaden för förnybar energi, är projektet inte genomförbart utan höga investeringsrisker. Men den här studien bör utvärderas igen inom en snar framtid när kostnaden för tidvattenanordningen har minskat.
264

An improved control strategy for wind-powered refrigerated storage of apples

Baldwin, John Derouet Couper 30 March 2010 (has links)
The need for an improved control strategy for the operation of a wind-powered refrigeration system for the storage of apples was investigated. The results are applicable to other systems which employ intermittently available power sources, battery and thermal storage, and an auxiliary, direct current power supply. Tests were conducted on the wind-powered refrigeration system at the Virginia Polytechnic Institute and State University Horticulture Research Farm in Blacksburg, Virginia. Tests were conducted on the individual components of the system. In situ windmill performance were also conducted. The results of these tests have been presented. An improved control strategy was developed to improve the utilization of available wind energy and to reduce the need for electrical energy from an external source while maintaining an adequate apple storage environment. / Ph. D.
265

Modeling of Bi-directional Converter for Wind Power Generation

Abu-hamdeh, Muthanna S. January 2009 (has links)
No description available.
266

Large Eddy Simulation and LIDAR 3-D Mapping for Optimization of Wind Power Generation in Limited-space Applications

Zhu, Kunpeng 20 October 2011 (has links)
No description available.
267

Urban vindkraft i Malmö

George, Bica January 2010 (has links)
Sverige är ett föregångsland när det gäller miljöarbetet men har inte tillhört de ledande länderna på vindkraftsområdet. Vindkraftsproduktionen i den urbana miljön är sällsynt på den svenska marknaden. Uppsatsens syfte är att undersöka vad som menas med urban vindkraft, belysa vilka problem och hinder finns för vidare utveckling och berätta om framtidsplanerna för urban vindkraft i Malmö. Vidare försöker jag även redogöra för vilken påverkan urban vindkraft har på vårt samhälle. Uppsatsen grundar sig på analys av artiklar som behandlar urban vindkraft, studier av rapporter samt intervjuer med ansvariga för dem olika projektet som pågår i Malmö idag. Studien visar att urban vindkraft är en bra och miljövänligt förnyelsebar energikälla. Det finns problem och samhälleliga konflikter som måste lösas för att urban vindkraft skall utvecklas vidare. Med hjälp av forskning, riktade satsningar och noggrann uttänkt planering kan den få plats i stadsmiljön. Utifrån studiens design, får jag uppfattningen att en utvärdering av situationen för urban vindkraft, är först möjligt om ett antal år, då alla pilotprojekt har varit igång och kan förse oss med värdefull information. Urban vindkraft skulle kunna bidra med ekonomisk och miljömässig nytta till samhällsutvecklingen i framtiden. / Sweden is a leading country in environmental work but has not been among the leading countries in wind power. Wind power generation in the urban environment is rare in the Swedish market. The purpose of this thesis is to examine what is mean by urban wind power, highlighting the problems and obstacles for further development and present plans for urban wind power in Malmö. Furthermore, I try to also to explain the impact of urban wind power has on our society. The essay is based on an analysis of articles dealing with urban wind power, studies of reports and interviews with those responsible for various projects going on in Malmö today. The study shows that urban wind power is a good, environmentally friendly renewable energy source. There are problems and social conflicts to be resolved for urban wind power to be developed further. Through research, targeted investments and careful planning, wind power can devised to fit in the urban environment. Based on the study design, I believe that an assessment of the situation of urban wind power is only possible in a couple of years, when all the pilot projects have been running for a while and can provide us with valuable information. Urban wind power could contribute to economic and environmental benefits to society in the future.
268

Empowering wind power : on social and institutional conditions affecting the performance of entrepreneurs in the wind power supply market in the Netherlands /

Agterbosch, Susanne. January 1900 (has links)
Univ., Copernicus Institute for Sustainable Development and Innovation, Diss.--Utrecht, 2006. / Zsfassung in niederländ. Sprache.
269

A methodology to enable wind farm automatic generation control

Han, Hai-Yue 03 January 2012 (has links)
Over the last decade the increase in penetration of wind power and its variable nature has begun to add considerable stress to and threatened the stability of the nation's grid. In order to continue growth wind farms will need to have the ability to participate in the same grid frequency regulation as traditional generating sources. The goal of this research is to explore the use of energy storage devices to provide wind farms with a method to regulate their power output and the grid frequency. Using energy storage, this research aims to allow wind farms to participate in automatic generation control (AGC). Software simulations were performed to design an advanced energy storage controller that will allow maximum participation in AGC. A comprehensive in-lab grid was constructed to produce experimental results for this work and was used to evaluate the performance of the advanced energy storage controller. The first stage of this research aims to use super-capacitors to balance rapid excursions in frequency and wind power output while the second stage of this research will preliminarily explore the use of a zinc-bromine flow cell battery for medium-scale, sustained excursions in frequency and wind power output. Results show that wind farms are capable of participation in AGC with the addition of an energy storage device, but the amount of participation is heavily reliant on the amount of energy storage available. / Graduation date: 2012
270

Comparison of fixed diameter and variable diameter wind turbines driving a permanent magnet hub motor

Pietrangeli, Sven January 2012 (has links)
Thesis submitted in fulfilment of the requirements for the degree MAGISTER TECHNOLOGIAE: Mechanical Engineering in the FACULTY OF ENGINEERING at the CAPE PENINSULA UNIVERSITY OF TECHNOLOGY, 2012 / The amount of power a horizontal axis wind turbine (HAWT) can produce is determined by two main factors, wind velocity and rotor swept area. Theory dictates that the power production of a horizontal wind turbine is related to the cube of wind velocity and the square of the turbine diameter (or radius). The power produced at any given time is thus dependent on of the wind velocity and the rotor swept area of the turbine. Wind is variable in availability and consistency. Very little can be done to effect the wind velocity passing through the turbine rotor area and its effect is minimal. Thus understandably if more power is required, from the same wind velocity, the rotor diameter must be increased. A variable length blade can adapt lengthwise to accommodate low wind velocities and similarly high wind velocities during extreme conditions, thus increasing the operational time and power production of the turbine. The work undertaken in this thesis is a comparative study between standard design, fixed length blades to that of a modified design, variable length blade. The project entailed the design and development of small diameter HAWT blades and experimental testing. The turbine blades were designed using applicable theory and manufactured from available materials. For the experiments, the turbine was mounted on a vehicle and driven at various speeds. Due to size limitations, no dynamic adaption was done during testing. The variable length design blade was obtained by cutting increments off. The results obtained from each test were compared at corresponding points and conditions. Final interpretation of results lead to the conclusion that by increasing or decreasing the turbine blade length the area of turbine energy capture can be adjusted to affect the amount of power produced. Additional benefits included, force reduction during extreme operating conditions, extended production period for the turbine and a mechanical start up method during low wind speeds. The financial feasibility did not form part of the scope of this thesis and the technical feasibility of the concept can be thoroughly addressed in future research.

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