A critical requirement of any remote microgrid is its capability to control the balance between electric generation and load within the confines of the microgrid itself. The integration of significant amounts of “as available” renewable generation to any electric grid (macro or micro) makes it more difficult to maintain this balance and can result in large frequency deviations on a microgrid. Ancillary services provide the resources required to maintain the instantaneous and ongoing balance between generation and load. Battery energy storage systems (BESS) can provide regulating reserves, a type of ancillary service, by modulating active power for frequency control, referred to as load frequency control (LFC), to reduce frequency deviations caused by sudden changes in renewable generation. Historically, the most common methodology for reducing frequency disturbances exacerbated by wind plants with BESS systems is ramp rate control and more recently lead compensation. This thesis proposed a modified lead compensator for use in microgrid applications. A PSS®E microgrid model, based upon existing validated models, was developed to test the effectiveness of the LFC controllers used to dispatch the BESS as a regulating resource to allow increased wind energy penetration levels on remote microgrids. A model of the remote microgrid of the island of Maui, Hawaii was chosen as the basis for the designs. Daily wind power data from 2012 was classified and indexed on an hourly basis by severity of variation. The worst hour for power variation from the wind plants was identified from this indexing and used as the basis for simulating the LFC controllers. The results compared the effectiveness of droop, ramp rate, lead compensation, and modified lead compensation controllers in reducing the variability in the grid frequency caused by changes in wind power generation. An RMS of variation with respect to an average over different time windows was used as the comparison metric. The combined modified lead compensator with ramp rate control showed the best performance of the overall system behavior. / text

El objetivo principal es la evaluación de la biomasa como recurso energético renovable en Cataluña. Su alcance requiere el estudio de diversas temáticas, desarrolladas en los doce capítulos que componen el documento.El Capítulo 1 describe los objetivos de la tesis. El Capítulo 2 describe los motivos que justifican la valorización energética del recurso biomasa. El Capítulo 3 presenta la metodología general utilizada. El Capítulo 4 realiza un análisis multicriterio del aprovechamiento energético de biomasa forestal. El Capítulo 5 cuantifica la biomasa disponible para usos energéticos en Cataluña. Los Capítulos 6, 7, 8 y 9 analizan las tecnologías y la viabilidad de la producción de energía con colza y chopo. El Capítulo 10 caracteriza físico-químicamente la biomasa de colza como combustible complementario al actual uso del grano para biodiesel. El Capítulo 11 evalua el uso de cultivos para la producción de productos químicos. El Capítulo 12 resume las Conclusiones generales. / The main goal is the evaluation of biomass as renewable resource in Catalonia. Its scope requires the study of different subjects, developed in the twelve chapters that compose the document. The Chapter 1 describes the goals of the PhD thesis. The Chapter 2 describes the reasons that justify the energetic use of biomass. The Chapter 3 shows the general methodology used. The Chapter 4 carries out a multicriterion analysis of energetic valorisation of forestry biomass. The Chapter 5 quantifies the available biomass for energy production in Catalonia. The Chapters 6, 7, 8 and 9 analyze the technologies and the feasibility of power generation using rapeseed and poplar energy crops. The Chapter 10 characterizes physical-chemically the rapeseed biomass as complementary fuel to the current use of the grain for bio-diesel production. The Chapter 11 evaluates the potential use of other crops for chemicals production. The Chapter 12 summarizes the Main Conclusions.

Orientadores: Ieda Geriberto Hidalgo, Paulo de Barros Correia / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica / Made available in DSpace on 2018-08-27T21:54:34Z (GMT). No. of bitstreams: 1 ContrerasMedellin_VivianaAndrea_M.pdf: 2918970 bytes, checksum: d3e29b2d5269f327c32b83ecc013aa6a (MD5) Previous issue date: 2015 / Resumo: A geração de energia elétrica a partir de fontes renováveis constitui uma alternativa interessante para a diversificação da matriz energética de um país. No Brasil, o programa de incentivo às fontes alternativas de energia elétrica (Proinfa), instituído em 2004, teve como objetivo promover a diversificação da matriz energética, buscar alternativas para aumentar a segurança no abastecimento de energia elétrica e permitir a valorização das características e potencialidades regionais e locais. Dentre as fontes renováveis de geração de energia, o destaque deste trabalho é para a biomassa, utilizando o bagaço da cana-de-açúcar. O bagaço da cana é produzido em grandes quantidades no Brasil e possui 1/3 do conteúdo energético da cana. Este recurso permite a geração de energia descentralizada. No setor elétrico brasileiro, a contratação de energia proveniente de empreendimentos de geração a partir do bagaço da cana-de-açúcar pode ser formalizada por meio dos leilões de energia de reserva. A análise de projetos para empreendimentos deste tipo envolve duas variáveis estocásticas: a geração de energia (que depende da disponibilidade do recurso ¿ período sazonal) e o valor da energia no mercado de curto prazo (que depende das condições hidrológicas). Portanto, este trabalho apresenta um modelo de valoração probabilística, para empreendimentos de geração a partir do bagaço da cana-de-açúcar, em leilão de energia de reserva. Esta valoração é feita sob a ótica do empreendedor que deve saber qual é o limite do seu lance no leilão. Deste modo, o destaque da valoração probabilística é para o valor presente líquido (VPL), que determina a medida da probabilidade de ganho ou perda para o empreendedor que participa no leilão de energia de reserva. O método de simulação de Monte Carlo e o fluxo de caixa livre descontado são utilizados para a valoração probabilística. Três estudos de casos são apresentados para uma usina de geração de energia de São Paulo. Para cada cenário simulado, a distribuição de probabilidade do VPL, o VPL médio e a taxa interna de retorno (TIR), que faz com que o VPL médio seja nulo, são calculados. Avalia-se a sensibilidade do retorno do empreendimento para diferentes valores de investimento, taxa mínima de atratividade (TMA) e lance. Os resultados deste trabalho indicam que o benefício, representado pelo VPL do empreendimento, é muito sensível ao valor do lance. Conclui-se também, que a metodologia apresentada pode ser empregada como um instrumento para que os empreendedores, que participam de leilões de contratação de energia possam avaliar o riscos de ter uma perda, decorrente do seu lance dado no leilão / Abstract: Electricity generation from renewable sources is an interesting alternative to diversify the energy matrix of a country. In Brazil, the incentive program for alternative electricity sources (Proinfa), established in 2004, had as goals, promoting the diversification of energy matrix, looking for alternatives to increase energy supply security and allowing the enhancement of the regional and local characteristics and potentials. Among the renewable sources of energy generation, the highlight of this work is to biomass, using bagasse from sugarcane. The bagasse is produced in large quantities in Brazil and it has one third of the sugarcane energy content. This source allows a decentralized power generation. In the Brazilian electricity sector, energy contracting from generation projects that use sugarcane bagasse, as a source, can be formalized through reserve energy auctions. The analysis of this type of projects involves two stochastic variables. Power generation (which depends on the resource availability - seasonal period) and energy price in the spot market (which depends on the hydrological conditions). Therefore, this work presents a probabilistic valuation model for generation projects that use sugarcane bagasse and commercialize energy in reserve energy auctions. This valuation is made from the entrepreneur perspective, who must know which is his auction bidding limit. Thus, the highlight of probabilistic valuation is for the net present value (VPL), which determines the probability measure of gain or loss, for the entrepreneur participating in the reserve energy auction. The Monte Carlo simulation method and the discounted free cash flow are used for the probabilistic valuation. Three case studies are presented for a power generation plant located in São Paulo state. For each simulated scenario, the probability distribution of VPL, the average VPL and the internal return rate (TIR), that make average VPL to be zero, are calculated. Sensitivity of the project¿s return is evaluated to different investment values, minimum acceptable rates of return (TMAs) and auction biddings. The results in this study indicate that the earns, represented by venture VPL, are highly sensitive to auction bidding value. It is also concluded that the methodology presented can be used as an instrument to assist investors, participating in reserve power auctions, in assessing the risk of loss, resulting from its auction bidding / Mestrado / Planejamento de Sistemas Energeticos / Mestra em Planejamento de Sistemas Energéticos

[pt] O setor elétrico é estratégico para o país, estando presente no dia-a-dia da população, além de ser fundamental para todos os setores. A participação do setor também é muito importante na redução das emissões de gases poluentes. Com o aumento da demanda por energia, o forte potencial das fontes eólica e solar no Brasil favorece as empresas geradoras de energia por fontes renováveis e, consequentemente, aumenta a competição no setor. Com esse aumento e a busca por recursos complementares, principalmente por meio de inovação, as alianças estratégicas contribuem para um melhor desempenho das empresas. Neste contexto, existe uma necessidade de tecnologias cada vez mais sustentáveis para atender aos interesses ambientais e sociais. Portanto, as inovações orientadas à sustentabilidade são imprescindíveis para se alcançar vantagem competitiva no setor. O estudo de caso realizado em uma empresa de energia elétrica permitiu avaliar as implicações estratégicas para inovação orientada à sustentabilidade por meio das redes/alianças no setor elétrico, especialmente pelas fontes eólica e solar, com a utilização do ferramental de análise estratégica SNA-SOI (Macedo-Soares, 2018). A pesquisa demonstrou a adequação estratégica da empresa focal, constatando que a ótica relacional adiciona valor à análise tradicional ao proporcionar importantes lições para a tomada de decisão dos administradores, notadamente, uma visão mais ampla das oportunidades e ameaças externas, uma melhor análise das forças e fraquezas dos parceiros e dos seus relacionamentos, além de um maior conhecimento sobre o posicionamento e a influência dos atores estratégicos do setor, considerando as características da rede que os integra. / [en] The electric sector is strategic for the country, being present in the day to day of the population, besides being fundamental for all industries. The participation of the electric sector is also crucial in the efforts to reduce greenhouse gas emissions. With the increasing demand for energy, the strong potential of wind and solar sources in Brazil favors companies that generate energy from renewable sources and, consequently, increases competition in the sector. With this increased competition and the search for complementary resources, mainly through innovation, strategic alliances contribute to a better performance of companies. In this context, there is a need for increasingly sustainable technologies to meet environmental and social interests. Therefore, sustainability-oriented innovations are essential to gain competitive advantage in the industry. The case study carried out at a major power company allowed us to evaluate the strategic implications for innovation oriented towards sustainability through networks/alliances in the electric sector, especially wind and solar sources, using the SNA-SOI strategic analysis tool (Macedo -Soares, 2018). The research demonstrated the adequateness of the focal company s strategy, noting that the relational perspective adds value to traditional strategic analysis by providing important lessons for managers decision making, notably, a broader view of external opportunities and threats, a better analysis of the strengths and weaknesses of partners and their relationships, as well as greater knowledge about the positioning and influence of the sector s strategic actors, considering the characteristics of the network that integrates them.

Σκοπός της παρούσας διπλωματικής εργασίας είναι η παρουσίαση των κυριότερων μεθόδων παραγωγής ηλεκτρικής ενέργειας και η ανάλυση όλων των οικονομικών παραμέτρων ώστε να επιτύχουμε τη σχεδίαση του βέλτιστου συστήματος. Στο πρώτο κεφάλαιο γίνεται μία παρουσίαση των κυριότερων μονάδων παραγωγής ενέργειας. Αναφέρονται οι αρχές λειτουργίας και το κύκλωμα πάνω στην οποία βασίζεται ο κάθε σταθμός, ο βαθμός απόδοσης του κάθε συστήματος και τα πλεονεκτήματα και μειονεκτήματα αυτών. Αρχικά παρουσιάζονται οι ατμοηλεκτρικές, οι αεριοστροβιλικές και οι συνδυασμένου κύκλου συμβατικές μονάδες. Εξηγείται ο θερμοδυναμικός κύκλος λειτουργίας του Rankine πάνω στον οποίο βασίζεται η λειτουργία τους και οι προϋποθέσεις βέλτιστης λειτουργίας. Περιγράφεται ο κύκλος λειτουργίας και οι μετατροπές ενέργειας που πραγματοποιούνται στους στροβίλους και τα πρόσθετα μηχανήματα. Στην συνέχεια γίνεται αναφορά στους υδροηλεκτρικούς σταθμούς ροής ποταμού και αποθήκευσης ενέργειας. Εξηγείται η μελέτη για την δημιουργία ενός τέτοιου σταθμού, αναλύονται οι υποδομές και οι κτιριακές εγκαταστάσεις που απαιτούνται. Κατόπιν, περιγράφονται οι πυρηνικοί σταθμοί. Αναλύεται η πυρηνική σχάση, παρουσιάζεται ο πυρηνικός αντιδραστήρας και τα είδη του. Εν συνέχεια, επισημαίνονται οι ανανεώσιμες πηγές ενέργειας. Για τα αιολικά συστήματα μελετάται η εγκατάστασή τους και τα κύρια χαρακτηριστικά τους. Αναφέρεται η δομή της ανεμογεννήτριας, η αρχή λειτουργίας και τα διάφορα είδη ανεμογεννητριών και αιολικών πάρκων που βρίσκουν εφαρμογή σήμερα. Για τα φωτοβολταϊκά συστήματα, περιγράφεται η βασική αρχή λειτουργίας τους, το φωτοβολταϊκό φαινόμενο καθώς και η δομή του συστήματος. Αναλύονται τα συστήματα επίπεδων και συγκεντρωτικών πλαισίων που υπάρχουν και οι διάφορες συσκευές που απαρτίζουν το φωτοβολταϊκό σύστημα. Επίσης, περιγράφονται τα συστήματα που είναι συνδεδεμένα στο δίκτυο, καθώς και τα απομονωμένα. Κλείνοντας το κεφάλαιο, αναφέρονται τα γεωθερμικά συστήματα, οι κυψέλες καυσίμου και τα συστήματα παραγωγής ηλεκτρισμού από ενέργεια βιομάζας και παλιρροϊκής. Στο δεύτερο κεφάλαιο παρουσιάζονται οι πηγές ενέργειας και συγκεκριμένα τα ορυκτά καύσιμα. Γίνεται μία κατηγοριοποίηση σύμφωνα με τον ενεργειακό πόρο, εξετάζοντας τα αποθέματα, τη ζήτηση και την παραγωγή τους. Δίνονται πληροφορίες για το πετρέλαιο, το φυσικό αέριο, τον άνθρακα και τα πυρηνικά καύσιμα. Ιδιαίτερη έμφαση δίνεται στον λιγνίτη, λόγω των αποθεμάτων που υπάρχουν στην χώρα μας, και παρατίθεται μία ανάλυση ενός λιγνιτικού θερμοηλεκτρικού συστήματος. Στο τρίτο κεφάλαιο παρουσιάζεται ο τρόπος σχεδιασμού ενός βέλτιστου συστήματος. Για την παραγωγή του βέλτιστου συστήματος πρέπει να ληφθούν υπόψη πολλοί παράμετροι που περιλαμβάνουν την πηγή ενέργειας, τον τύπου του ενεργειακού συστήματος, την εκτίμηση του κόστους παραγωγής και των εγκαταστάσεων καθώς και την επιλογή τοποθεσίας. Αυτές οι αποφάσεις βασίζονται σε έναν αριθμό από τεχνικούς, οικονομικούς και περιβαλλοντικούς παράγοντες που είναι σε μεγάλο βαθμό άσχετοι μεταξύ τους. Αναφέρονται οι μέθοδοι υπολογισμού του κόστους συντήρησης και λειτουργίας ενός ενεργειακού συστήματος. Γενικά ως συμπέρασμα δεν μπορούμε να καταλήξουμε σε έναν κανόνα, γιατί η βέλτιστη λύση είναι απόρροια αναγκών, προτεραιοτήτων και παραμέτρων που προκύπτουν σε κάθε περίπτωση Στο τέταρτο κεφάλαιο αναπτύσσεται μία μελέτη οικονομικής φύσεως. Για μια ενεργειακή επένδυση είναι απαραίτητη μία ανάλυση δαπανών του κύκλου ζωής της. Μέσω της ανάλυσης αυτής αξιολογούνται οι συνολικές κύριες και λειτουργικές δαπάνες, λαμβάνεται υπόψη η «χρονική αξία» των χρημάτων και ενσωματώνονται οι διακυμάνσεις στην τιμή των καυσίμων. Η ανάλυση δαπανών κύκλων ζωής εξετάζει το κόστος κατά τη διάρκεια της ζωής του συστήματος και όχι μόνο το αρχικό κόστος. Έτσι είναι ευκολότερη η συγκριτική μελέτη των συστημάτων που θέλουμε να εγκαταστήσουμε. Στο πέμπτο κεφάλαιο ως αποτέλεσμα ενός οικονομικότερου οπότε και βέλτιστου συστήματος αναφέρεται η συμπαραγωγή ηλεκτρισμού και θερμότητας. Τα συστήματα Συμπαραγωγής Ηλεκτρισμού και Θερμότητας παράγουν ταυτόχρονα αξιοποιήσιμη ηλεκτρική και θερμική ενέργεια μέσω ενός ενιαίου συστήματος. Η παραγόμενη θερμότητα μπορεί να χρησιμοποιηθεί τόσο για θερμική χρήση όσο και για ψύξη ή κλιματισμό. Βασικό πλεονέκτημα και κίνητρο εφαρμογής της αποτελεί η αυξημένη απόδοση του συστήματος, έναντι της χωριστής λειτουργίας συμβατικών συστημάτων ηλεκτροπαραγωγής και θερμικής ενέργειας. Η εξοικονόμηση αυτή προκύπτει από την ανάκτηση και αξιοποίηση της θερμότητας, που διαφορετικά θα απορριπτόταν στο περιβάλλον Στο έκτο και τελευταίο κεφάλαιο παρουσιάζεται το ελληνικό σύστημα παραγωγής ηλεκτρικής ενέργειας. Το Ελληνικό ενεργειακό σύστημα βρίσκεται την τελευταία δεκαετία σε φάση σημαντικών αλλαγών. Η διείσδυση του φυσικού αερίου, η κατασκευή των διευρωπαϊκών δικτύων, η προώθηση των ανανεώσιμων πηγών ενέργειας και εξοικονόμησης ενέργειας και τέλος η απελευθέρωση της αγοράς ηλεκτρικής ενέργειας αποτελούν τα νέα δεδομένα του. Σημαντικές είναι οι επιπτώσεις των νέων αυτών δεδομένων στην ασφάλεια του ενεργειακού εφοδιασμού της χώρας, στην μείωση της εξάρτησης της από το εισαγόμενο πετρέλαιο, με όλα τα συνεπαγόμενα οφέλη στην εθνική οικονομία, στην εξοικονόμηση μη ανανεωνόμενων ενεργειακών πόρων, στην αύξηση της αποδοτικότητας των διαδικασιών παραγωγής και κατανάλωσης ενέργειας, στην προστασία του περιβάλλοντος και τέλος στην βελτίωση των παρεχομένων υπηρεσιών στους καταναλωτές. / The subject of this diploma thesis is the study of the types of electric generation systems and their comparative study. Initially are presented summarizing the basic principles of operation and the particular characteristics of each station. The energy systems being analyzed are steam cycle, gas fired, combined cycle, hydroelectric, nuclear power, solar, wind, geothermal and biomass systems. A brief description of fuels takes place presenting oil, natural gas, coal and its derivatives and nuclear fuels. Accent is given in the lignite and a short description of a lignite thermoelectric station is given. Then, the criteria are mentioned which are suitable for the choice of optimal energy system such as operational and functional costs, prices of fuels, types of generation system and technical and environmental issues. Also an economic study is realized. A life cycle cost analysis that evaluates the total owning and operating cost and takes into account the “time value” of money. Furthermore, the co-production of energy and heat as emanation of the most optimal system is included. Finally, the energy situation that prevails in Greece is presented.

Dissertation (DTech(Electrical Engineering))--Cape Peninsula University of Technology, 2012 / The confluence of the limited resources of fossil fuels (e.g. coal, oil and natural gas), environmental degradations leading to climate change, security of supplies and fossil fuels high costs have demanded a tremendous efforts on humanity to seek for a sustainable and unlimited natural energy sources. Amongst these renewable energy sources stands out solar energy because of its ubiquitousness. Solar energy is converted to DC electricity by the photovoltaic effect. Photovoltaic (PV) power systems installed in commercial and industrial buildings are a good example of distributed power generation. Here the energy consumption and production match and thus electricity taken from the grid during daytime peak hours can be reduced. This is beneficial as the transmission losses in the grid are avoided and also transmission need is reduced. The cost effectiveness of a solar energy system has hindered its wide adoption and deployment in terms of the initial capital cost even though it has a zero energy cost and very minimal operating and maintenance costs. Different governments have instituted many financial incentives for fast adoption of PV systems for both residential and commercial applications. However, all these incentives are not sustainable in the longer term forecast. For PV system to attain grid parity requires more than unsustainable approach of many governments providing time limited subsidies. The technical solution to the problem is to reduce the overall system cost through technical innovations. One such method is the adoption of transformerless inverter technology as the grid interface system. Transformerless inverter topology provides galvanic isolation through innovative inverter topology and switching strategies that eliminates problems created by not employing the service of transformer.