Published Article / The world is increasingly being misused by its inhabitants by the wasteful manner that its resources are utilized and the amount of pollution that is generated in the environment. This practice is unsustainable and it is incumbent on the present generation of decision-makers to rectify this phenomenon if our descendants are to have an opportunity to live life in the same manner as we do. Special emphasis should be placed on a reduction in the amount of air pollution that is created by electrical power generating plants, as well as the manner in which potable water is utilized and wasted. In this article the local situation with respect to the generation and use of electrical energy and water is discussed. It is encouraging to see that the National Government is taking strong steps to address these problems. Yet, it might not have the required ability to finance these efforts fully.

Synchrone Messungen der Windgeschwindigkeit und die Leistung von Windkraftanlagen dienen der Ermittlung der Kennlinien der Anlagen. Die existierenden Vorschriften zur Vermessung enthalten bezüglich der Strömungseigenschaften des Windes nahezu keine Spezifikationen. Diese sind jedoch notwendig, um die erreichbare Genauigkeit und Repräsentativität der vermessenen Kennlinie zu quantifizieren. Messungen am Standort der AEOLUS II-Anlage in Wilhelmshaven dienten dazu, bei einer Anlagenvermessung die Eigenschaften der Strömung und die Kennlinie gemeinsam zu untersuchen. Es wurde gefunden, daß die Strömungseigenschaften wie die vertikale Windscherung, die Winddrehung über der Höhe, die turbulenten Schwankungen der Windgeschwindigkeit und der Windrichtung die Leistung von Windenergieanlagen bei gleicher mittlerer Windgeschwindigkeit erheblich verändern. Dabei wirken sowohl Standorteigenschaften als auch die Witterung auf die Ergebnisse der Vermessung. Am gleichen Standort können in anisotropem Gelände die Werte der Kennlinie auch bei mehrmonatigen Vermessungen wegen der Variabilität der Windrichtung Unterschiede von mehr als 10 % aufweisen. Der größte Einzeleffekt wird von der vertikalen Windscherung verursacht, die Wirkung der Drehung des mittleren Windvektors über der Rotorfläche ergab sich als kleinerer Effekt. Die Wirkung der turbulenten Schwankungen von Geschwindigkeit und Richtung weisen meist unterschiedliche Vorzeichen auf, so daß die Rolle dieser Schwankungen insgesamt meist klein bleibt. Die Vermessung einer Kennlinie mit einer kleineren systematischen Abweichung von im Mittel weniger als etwa 5 bis 10 % erfordert eine genaue Strömungsspezifikation sowohl für den Vermessungs- als für den Betriebsstandort, die bisher nicht in hinreichendem Maße in den entsprechenden Richtlinien und Vorschriften enthalten sind. / Power curves ofwind energy convetras need synchronous measurements of wind and power. The existing specification on the wind measurements are rather poor, however necessary. AEOLUS II-measurments and the wind measurments served to quantify the role of the different atmospheric parameters. Thus it was possible to define the influence on the power output of the machine as a function of the vertical wind shear, the wind veer with height, the turbulent fluctuations with the average wind speed being constant. As a consequence site properties and weather conditions both influence the measurements of the power curve. As a major result it was found that these factors may alter the power curve by as much as 10 %. The largest single effect is produced the effects of the vertical wind shear, The turbulent fluctuations are somewhat smaller in their effect, because speed and direction effects tend to compensate each other. lt may be concluded that a highly accurate power curve - meaning errors to be less than 10 % - requires a fully specified set of weather and site parameters.

Este trabalho apresenta o estudo da dinâmica de uma instalação propulsora a vapor através da técnica da modelagem e simulação. O modelo matemático é obtido das Leis da Termodinâmica e dos conceitos básicos da mecânica dos fluídos e transferência de calor, e a simulação é efetuada em um computador digital. Inicialmente cada componente do ciclo é modelado individualmente, determinando-se as suas variáveis de estado, de entrada e de saída. A seguir o modelo é simulado para analisar a influência dos diversos parâmetros nas respostas do elemento. O modelo matemático da instalação propulsora a vapor é obtido agrupando-se convenientemente os modelos dos vários componentes do ciclo. Com isso obtêm-se um sistema de 47ª ordem que pode simular diversos casos de interesse real. Neste trabalho são analisadas as respostas do ciclo para dois casos. A primeira corresponde ao fechamento parcial da válvula de controle da turbina e a segunda ao corte na vazão de óleo combustível. / This paper presents a study of the dynamics of a steam power plant using techniques of modelling and simulation. The mathematical model derives form the laws of Thermodynamics and basic concepts of fluid mechanics and heat transfer; the simulation is carried out in a digital computer. Each component is first modelled individually, and its state, input and output variables are determined. The model is then simulated for the analysis of the influence of the various parameters in the responses of the component. The mathematical model of the complete power plant is constructed by the convenient grouping of the various component models of the cycle. Thereby a 47th order system is obtained, which can simulate various cases of interest. The cycle\'s response for two cases are analysed. The first case correspond to the partial closing of the turbine control valve and the second to the fuel flow interruption .

Orientador: José Tadeu Garcia Tommaselli / Resumo: A energia elétrica é uma modalidade da energia central para o desenvolvimento das forças produtivas na sociedade capitalista. O setor elétrico brasileiro tem como fonte principal de produção de energia elétrica, a hidroeletricidade, que no atual momento se tornou uma fonte de elevados lucros. As usinas hidrelétricas, inseridas no espaço geográfico, formam um conjunto de sistemas de objetos e ações construídos pelo trabalho dos trabalhadores, que na atualidade está sob o comando majoritário da iniciativa privada. A indústria da eletricidade é multiterritorial porque contém, dentro do território da energia, a geração, a transmissão, a comercialização e a distribuição e esta se liga ao território das demais matrizes construindo o território energético. Este texto busca entender o processo de instalação da Usina Hidrelétrica Estreito no rio Tocantins, localizado entre os estados do Tocantins e Maranhão. A implantação desta usina hidrelétrica é carregada de diversas estratégias por parte do consórcio empreendedor para ganhar o apoio da sociedade nas diversas escalas. Sua inserção provocou a desterritorialização de uma parcela de famílias, que anteriormente viviam na região e que, até hoje, buscam o reconhecimento como portadoras de direitos dos espaços ocupados. Esse processo trouxe conflitos entre as partes envolvidas e sua resolução vai depender da correlação de forças estabelecida no território. O conjunto de populações atingidas no Brasil formulou uma proposta que está em fase... (Resumo completo, clicar acesso eletrônico abaixo) / Mestre

This work considers the value of flexible power provision from natural gas-fired combined cycle (NGCC) power plants operating post-combustion carbon dioxide (CO2) capture in low carbon electricity markets. Specifically, the work assesses the value of the flexibility gained by varying CO2 capture levels, thus the specific energy penalty of capture and the resultant power plant net electricity export. The potential value of this flexible operation is quantified under different electricity market scenarios, given the corresponding variations in electricity export and CO2 emissions. A quantified assessment of natural gas-fired power plant integrated with amine-based post-combustion capture and compression is attempted through the development of an Aspen Plus simulation. To enable evaluation of flexible operation, the simulation was developed with the facility to model off-design behaviour in the steam cycle, amine capture unit and CO2 compression train. The simulation is ultimately used to determine relationships between CO2 capture level and the total specific electricity output penalty (EOP) of capture for different plant configurations. Based on this relationship, a novel methodology for maximising net plant income by optimising the operating capture level is proposed and evaluated. This methodology provides an optimisation approach for power plant operators given electricity market stimuli, namely electricity prices, fuel prices, and carbon reduction incentives. The techno-economic implications of capture level optimisation are considered in three different low carbon electricity market case studies; 1) a CO2 price operating in parallel to wholesale electricity selling prices, 2) a proportional subsidy for low carbon electricity considered to be the fraction of plant electrical output equal to the capture level, and 3) a subsidy for low carbon electricity based upon a counterfactual for net plant CO2 emissions (similar to typical approaches for implementing an Emissions Performance Standard). The incentives for variable capture levels are assessed in each market study, with the value of optimum capture level operation quantified for both plant operators and to the wider electricity market. All market case studies indicate that variable capture is likely to increase plant revenue throughout the range of market prices considered. Different market approaches, however, lead to different valuation of flexible power provision and therefore different operating outcomes.

Graduation date: 1998

Thesis (M.S.)--Virginia Polytechnic Institute, 1951. / Abstract. Vita. Includes bibliographical references (leaves 30-31). Also available via the Internet.

No description available.

Simulators for power plants can be used for many different purposes, like training for operators or for adjusting control systems, where the main objective is to perform a realistic behaviour for different operating conditions of the power plant. Due to an increased amount of variable energy sources in the power system, the role of the operators has become more important. It can therefore be very valuable for the operators to try different operating conditions like island operation. The aim of this thesis is to model the power system of a general combined-cycle power plant simulator. The model should contain certain components and have a realistic behaviour but on the same time be simple enough to perform simulations in real time. The main requirements are to simulate cold start, normal operation, trip of generator, a controlled change-over to island operation and then resynchronisation. The modelling and simulations are executed in the modelling software Dymola, version 6.1. The interface for the simulator is built in the program LabView, but that is beyond the scope of this thesis. The results show a reasonable performance of the power system with most of the objectives fulfilled. The simulator is able to perform a start-up, normal load changes, trip of a generator, change-over to island operation as well as resynchronisation of the power plant to the external power grid. However, the results from the changing-over to island operation, as well as large load losses during island operation, show an unreasonable behaviour of the system regarding the voltage magnitude at that point. This is probably due to limitations in calculation capacity of Dymola, and the problem has been left to further improvements due to lack of time. There has also been a problem during the development of a variable speed regulated induction motor and it has not been possible to make it work due to lack of enough knowledge about how Dymola is performing the calculations. Also this problem has been left to further improvements due to lack of time.

Thesis (M.S.)--Central Connecticut State University, 2002. / Thesis advisor: Robert Fischbach. " ... in partial fulfillment of the requirements for the degree of Master of Science in Organizational Communications." Includes bibliographical references (leaves 86-90). Also available via the World Wide Web.