Thesis (M.S.)--Oregon State University, 2008. / Printout. Includes bibliographical references (leaves 125-126). Also available on the World Wide Web.

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Thesis (M.S.)--Missouri University of Science and Technology, 2009. / Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed November 17, 2009) Includes bibliographical references (p. 67-70).

Thesis (Ph. D.)--Division of Geography, School of Geosciences, Faculty of Science, University of Sydney, 2006. / Title from title screen (viewed 15 January 2009). Submitted in fulfilment of the requirements for the degree of Doctor of Philosophy to the School of Geosciences, Faculty of Science. Includes bibliographical references. Also available in print form.

Στην εργασία αυτή παρουσιάζονται κάποια στοιχεία για τα ΑΠΕ και τα χαρακτηριστικά τους αλλά δίνεται περισσότερη έμφαση στο ελληνικό σύστημα παραγωγής ηλεκτρικής ενέργειας (στους σταθμούς παραγωγής είτε ιδιωτικούς είτε της ΔΕΗ) τόσο από συμβατικές όσο και από ΑΠΕ. Στη συνέχεια, αναφέρονται εκτενέστερα οι πηγές ενέργειας που θα χρησιμοποιηθούν στις εξομοιώσεις, δηλαδή η ηλιακή ενέργεια, η αιολική ενέργεια και η τεχνολογία του υδρογόνου (που περιλαμβάνει κελιά καυσίμου, ηλεκτρόλυση του νερού για την παραγωγή υδρογόνου και την αποθήκευση του τελευταίου). Η μπαταρία ως αποθηκευτική μονάδα αναπτύσσεται συνοπτικά και κατόπιν αναφέρονται τα οικονομικά στοιχεία ενός συστήματος παραγωγής ηλεκτρικής ενέργειας. Το τελευταίο θεωρητικό κομμάτι είναι αφιερωμένο στο πρόγραμμα εξομοίωσης που χρησιμοποιήθηκε, το Homer, και αναλύονται λεπτομερώς τα δεδομένα που χρησιμοποιήθηκαν καθώς και οι τεχνικές λειτουργίας του. Στο τελευταίο κομμάτι της διπλωματικής εργασίας πραγματοποιούνται οι εξομοιώσεις στο Homer για ένα υβριδικό αυτόνομο σύστημα παραγωγής ηλεκτρικής ενέργειας και παρατίθονται τα αποτελέσματα αυτών με τη βοήθεια των διαγραμμάτων που παρέχει το συγκεκριμένο πρόγραμμα. Αρχικά, παρατίθονται τα δεδομένα που χρησιμοποιήθηκαν, δηλαδή η περιοχή για την οποία έγιναν οι εξομοιώσεις με τα αιολικά και τα ηλιακά δεδομένα, τα στοιχεία που χρησιμοποιήθηκαν στις εξομοιώσεις, τα είδη των ανεμογεννητριών,των φωτοβολταϊκών πλαισίων, των κελιών καυσίμου, των ηλεκτρολυτών, των μονάδων αποθήκευσης υδρογόνου, των μπαταριών, των αντιστροφέων και των γεννητριών, καθώς και τα οικονομικά στοιχεία που θέσαμε ως δεδομένα για την πραγματοποίηση των εξομοιώσεων. Οι εξομοιώσεις που πραγματοποιήθηκαν ήταν ο συνδυασμός ανά δύο όλων των παραπάνω πηγών ενέργειας και μια με όλες μαζί (δηλαδή 6 εξομοιώσεις), με σκοπό την ανεύρεση του πιο οικονομικού συνδυασμού ενός υβριδικού αυτόνομου συστήματος παραγωγής ηλεκτρικής ενέργειας για μια περιοχή κοντά στο Ηράκλειο Κρήτης που εξετάζουμε. Οι εξομοιώσεις πραγματοποιήθηκαν τόσο με την χρήση μπαταριών όσο και χωρίς την χρήση αυτών για να διαπιστωθεί κατά πόσο οι μπαταρίες επηρεάζουν ένα αυτόνομο σύστημα. Από τα αποτελέσματα των εξομοιώσεων δεν συμπεραίνεται με ακρίβεια ποια είναι η πιο συμφέρουσα καθώς αυτό εξαρτάται από τα κριτήρια που θέτει ο κάθε επενδυτής. Αυτά είναι: • Με βάση τη χρήση ή μη των μπαταριών • Με βάση τη συνολική παραγόμενη ενέργεια • Με βάση τo συνολικό κόστος της επένδυσης • Με βάση το πλεόνασμα παραγόμενης ενέργειας • Με βάση ποια συστήματα παραγωγής ενέργειας είναι υπεύθυνα για την μόλυνση του περιβάλλοντος • Με βάση την κλίση των φ/β πλαισίων, σύμφωνα με τα αποτελέσματα της ανάλυσης ευαισθησίας Οι κυριότεροι παράγοντες για την επιλογή ενός συστήματος παραγωγής ηλεκτρικής ενέργειας είναι ο οικονομικός και η εκπομπή ρύπων. Απ' τις εξομοιώσεις συμπεραίνεται ότι η πιο οικονομική επιλογή υβριδικού συστήματος παραγωγής ηλεκτρικής ενέργειας είναι ο συνδυασμός των πηγών γεννήτριας πετρελαίου – φωτοβολταικής συστοιχίας και ο συνδυασμός των πηγών φωτοβολταικής συστοιχίας-ανεμογεννήτριας είναι η πιο φιλική επιλογή προς το περιβάλλον μιας και δεν παράγει καθόλου ρύπους. Ανάμεσα στις δύο παραπάνω επιλογές, η πιο συμφέρουσα είναι η δεύτερη μιας και ως προς οικονομικής άποψης δεν είναι ακριβή (είναι η τρίτη πιο φθηνή), ενώ ο συνδυασμός γεννήτριας πετρελαίου – φωτοβολταικής συστοιχίας παράγει αρκετά υψηλό ποσοστό ρυπών (είναι η δεύτερη). Στο τέλος, πραγματοποιήθηκαν άλλες 3 εξομοιώσεις με το συνδυασμό της τεχνολογίας του υδρογόνου με τις υπόλοιπες ανανεώσιμες πηγές ενέργειας, μια κάθε φορά και όλες μαζί στο τέλος, με τις πιθανές μελλοντικές τιμές των στοιχείων της πρώτης (προβλέψεις για το 2020). Σύμφωνα λοιπόν με τα αποτελέσματα των εξομοιώσεων χρησιμοποιώντας τις μελλοντικές τιμές για την τεχνολογία του υδρογόνου, το μέλλον ανήκει σ αυτή την τεχνολογία και ο συνδυασμός της τόσο με την αιολική όσο και με την ηλιακή είναι μια οικονομική και συνάμα αποδοτική λύση χωρίς να μολύνουμε καθόλου το περιβάλλον. / In this project is presented things about renewable energy sources and their characteristics but is given more importance in the GPS, GREEK POWER SYSTEM, (either private power stations or NATIONAL ELECTRICAL COMPANY) by conventional sources and by Renewable Energy Sources. Afterwards, it is reported, extensively, to the energy sources that is used in simulations, in other words the solar energy, the wind energy and the hydrogen technology (that includes fuel cells, electrolyze of water for hydrogen production and the storage of the last one). It is developed the battery as stocking unit and then is reported to the economic elements of a power system. The last theoretical part is dedicated to the simulation program, HOMER and is analyzed its components and its techniques. In the last part of project, is simulated autonomous power systems and is commented their results, being helped by the diagrams that HOMER exports. Initially, it is mentioned the data that were used, that is to say the area with its solar and wind data, the elements that were used in the simulations, the types of wind generators, of photovoltaic frames, of fuel cells, of electrolytes, of hydrogen storages, of batteries, of inverter and of diesel generators, as well as the economic elements of simulations. The simulations contained the combination of the above sources of energy ( 6 simulations) aiming the recovery of the most lucrative combination of hybrid autonomous power system for an area close to Heraklion of Crete that was examined. The simulations were realized with the use of batteries and without them in order to understand their influences in autonomous power systems. The results of the simulations cannot lead, precisely, to a lucrative choice about a power system, something that depends on investor’s criteria. These are: • Based on the use or not of batteries • Based on the total production of energy • Based on the excess electricity • Based on the power system responsible for the pollution of the environment • Based on the photovoltaic tilt , according to the sensitivity results The main factors το choose an electric power system are the economic and the emission of pollutants. According to simulation results, the most economic choice of hybrid system is the combination of diesel generator - photovoltaic frames and the combination of photovoltaic frames-wind generator are the friendliest choice to the environment. Between the above choices, the second one is the most aproppriate due to its low cost, while the first one produces high percentage of pollutants. Finally, we realized 3 more simulations combined the technology of hydrogen, using possible future prices of its elements (forecasts for 2020), with the renewable energy sources. According to these results, the future belongs to hydrogen technology and its combination with the solar or the wind energy can create a cheap, efficient and without pollutants choice.

Orientador: Leonardo Nepomuceno / Banca: Marcelo Augusto Cicogna / Banca: Edmea Cassia Baptista / Resumo: No ambiente regulado, o planejamento da geração de energia é coordenado por um operador do sistema, que procura minimizar os custos da energia gerada e garantir a segurança energética para os consumidores e o atendimento da demanda. Este tipo de planejamento de geração não representa a lei de oferta e procura que ocorre em mercados de energia elétrica. No ambiente de mercado, os agentes apresentam suas ofertas de compra e venda em um ambiente competitivo que promove a livre concorrência. Este trabalho propõe um modelo de planejamento de geração de médio prazo, baseado na concorrência pela geração/consumo, em que empresas geradoras e consumidores fornecem lances em um leilão de energia de médio prazo. O modelo proposto é comparado ao modelo de planejamento centralizado de geração de energia. Os testes realizados no software GAMS, com pacote de solução CPLEX, indicam que o modelo proposto é uma alternativa para promover uma matriz energética mais variada e robusta a variações climáticas, além de manter a concorrência justa tanto para os consumidores quanto para os produtores de energia. / Abstract: In regulated hydrothermal electricity markets, power generation dispatch is coordinated by an independent system operator, that works to guarantee energy for consumers in the long-term, to meet the demand and to minimize the cost of generation. This type of dispatch does not represents the laws of supply and demand in the electricity market. In the deregulated auction market, the participants present their bids to purchase and sell, without the guarantee of being accepted, promoting free competition. This work presents a bibliographical research on electricity markets and the existing uncertainties of energy planning. Through optimization models, regulated dispatch is compared to an auction model for medium-term planning horizons. The tests performed in the GAMS software, with CPLEX solution package, indicate that the energy auction model is an alternative to promote the variation of the energy matrix, to turn it more robust to climate changes, in addition to maintaining fair competition for both the consumer and the producer. / Mestre

Battery charging wind turbines like, Hybrid Field Generator, have become more popular in the growing renewable energy market. With wind energy, voltage and current control is generally provided by means of power electronics. The paper describes the analytical investigation in to control aspects of a hybrid field generator controller for optimized performance. The project objective is about maintaining the generated voltage at 28V through out a generator speed range, between 149 rpm and 598 rpm. The over voltage load, known as dump load, is connected to the control circuit to reduce stress on the bypass transistor for speeds above 598 rpm. Maintaining a stable voltage through out the speed range, between 149rpm and 598rpm, is achieved by employing power electronics techniques. This is done by using power converters and inverters to vary the generator armature excitation levels hence varying its air gap flux density. All these take place during each of the three modes of generator operation, which are: buck, boost and permanent magnet modes. Although the generator controller is power electronics based, it also uses software to optimize its performance. In this case, a PIC16F877 microcontroller development system has been used to test the controller function blocks.

The threat of climate change has led to many countries and regions adopting renewable targets. Scotland's is one of the most ambitious, with an aim to generate the equivalent to 100% of its electricity needs from renewable sources by 2020. Scotland has a very large renewable resource, primarily consisting of offshore and onshore wind, tidal stream, wave and hydro power; all of which are characterised by having variable output. Over a long period, such as a year, variability in renewable generation will average out and may meet or exceed total annual demand. This thesis investigates whether matching of demand and generation is possible within a timescale meaningful to electricity system users; that is whether renewable generation can meet electricity demand in any given hour. This was established by using historic data to create an hourly generation hindcast of Scotland's renewable generation over a 30 year climate “normal” period. These outputs are then compared to a hindcast of hourly demand based on observations over the most recent few years. The results demonstrated that it is possible for Scotland to rely entirely upon renewable generation to fulfil demand in any hour of the 30 year hindcast. However, it appears that the renewable capacity and storage currently built or within the Scottish planning system is only sufficient to match demand in 65% of the hours within the hindcast. The hindcast allows judgements to be made as to how 100% of demand could be met most effectively and provides the basis of a coherent planning strategy, with security of supply at its centre. Further wave and tidal stream capacity is shown to be of higher value than additional wind power but in the latter case, addressing the geographical diversity of wind power can enable maximise phasing between sites to increase the security of supply. Importantly this work provides a means of informing decision making about where best to develop wind, wave and tidal resources and what additional storage may be required in order to provide 100% security of supply. The results are also of particular importance to Scotland's renewable generation strategy in the case of assessing where new on- and off-shore wind farms should be developed, as wind is set to dominate Scotland's renewable portfolio for the foreseeable future.

The research described in this dissertation was motivated by the global demand for energy that is not dependent on coal, oil, natural gas and other non-renewable fossil fuels. The technology used in this project is related to the use of biomass to produce a viable alternative to conventional sources of fuel. A bench scale biomass to liquid (BTL) facility was built and tested. This produced results confirming the feasibility of the BTL process. The findings of the pilot study outlined in this dissertation justified the conclusion that the next step will be to expand the capacity and productivity of the BTL pilot plant to an industrial scale. Biomass comes from a variety of renewable sources that are readily available. In this case, the material used in the fixed bed biomass gasification facility to generate wood gas was agricultural and forestry waste, such as straw and wood chips. The gasifier had the capacity to produce up to 10 cubic metres/hr of gas with a carbon monoxide and hydrogen content of between 20–40% by volume, when it was operated at ambient pressure and with air as the oxidizer. The gas, produced at a temperature above 700º C, was cooled in a quench/water scrubber in order to remove most of the mechanical impurities (tars and water-soluble inorganic particles), condensed and dried with corn cobs before being compressed in cylinders at over 100 bar (g) for use in the Fischer-Tropsch Synthesis (FTS). The syngas was subjected further to a series of refining processes which included removal of sulphur and oxygen. The sulphur removal technology chosen entailed applying modified activated carbon to adsorb H2S with the help of hydrolysis in order to convert organic sulphur impurities into H2S which reduced the sulphur content of the gas to less than 5 ppbv. Supported cobalt catalyst (100 grams), were loaded into a single-tube fixed bed FT reactor with an inner diameter of 50 mm. The reactor was fitted with a heating jacket through which, heated oil ran to cool the reactor during a normal reaction occurring at < 250 ºC, while nitrogen was used in the heating jacket during reduction, which occurred at temperatures up ~ 350 ºC. The FTS reaction was carried out at different pressures and temperatures. Liquid and wax products were produced from the facility. The properties of the liquid and solid hydrocarbons produced were found to be the same as FT products from other feed stocks, such as natural gas and coal.

The purpose of this study was to investigate the effect of same-day strength training on bat swing velocity of male collegiate baseball players. Sixteen male baseball players engaged in a preseason strength training program designed by the team's strength and conditioning coach. All subjects were tested for bat swing peak velocity immediately prior to ball impact for a non lifting day (NLD) by recording 10 swings with 30 seconds of rest in between swings. The next day, a lifting day (LD), all subjects tested on the NLD were tested four to six hours after the morning lifting session with the same amount of swings and rest. Six Vicon MX13+ infrared cameras (Vicon-Colorado, Centennial, Colorado), running at 400 Hz, were placed around the swinging area using Nexus 1.2 imaging software to download and determine bat swing peak velocity immediately prior to ball impact. The average of the top six bat swing peak velocity test results, for each subject, was compared to measures taken on the NLD and LD. A matched t-test revealed a significant difference in bat swing peak velocity between a NLD and a LD. A mean bat swing difference between NLD (69.18) and LD (70.86) of 1.68 was statistically different at better than the .05 level [p =.021]. This study suggests that male collegiate baseball players should be able to engage in a designed strength training program with a positive effect, and without any negative effect, on bat swing peak velocity when a strength training session is scheduled on the same day as a baseball competition.