Literatura científica selecionada sobre o tema "Production of electric energy or power. Powerplants. Central stations"

This paper focuses on research and innovation in the gas turbine industry. The production of nonaviation gas turbines was $3.6 billion in 1990, only 15% of total production. With improvement in thermal efficiency, increases in unit size, and the building of record breaking combined-cycle electric power plants fueled by cheap natural gas, nonaviation production zoomed to a euphoric high of $25.8 billion in 2001. The US Department of Energy announced last year the award of $130 million for 10 new projects to integrate hydrogen-burning gas turbines and turbine subsystems into integrated gasification combined cycle (IGCC) central power stations. Nuclear generation is also a zero-emissions technology, and Pebble Bed Modular Reactor Ltd, a South African company, is developing a gas turbine-nuclear reactor electric power plant, with participating companies that include Westinghouse, MHI of Japan, Nukem of Germany, and South Africa's Eskom.

The transition from the conventional internal combustion engine (ICE) to electric vehicles (EV) are expected to result in higher total electricity demand in the country. With the introduction of more EVs into the market, the need for charging stations will grow, subsequently increasing power consumption. This research study aims to assess the potential of solar energy production at petrol stations in central region of Peninsular Malaysia and assess the feasibility of solar-powered petrol stations in meeting the energy demands of electric vehicles. 10 samples of existing petrol stations are selected to install a solar-powered DC charging station as a case study. To study their energy consumption, 90kW DC charger was evaluated. The design of the PV systems for the petrol stations was done by using the PVsyst simulation software. As a result, it is found that 90% of the designed PV systems are able to generate enough energy to meet the estimated annual energy consumption of the 90kW DC charging system. The results also showed that the cost to install the solar-powered charging system for both power ratings can be recouped in less than 2 years. Overall, this research study offers valuable insights for addressing the rising energy consumption resulting from the increased penetration of electric vehicles in the future. Additionally, the implementation of solar-powered charging infrastructure aligns with the country’s renewable energy objectives and efforts to reduce greenhouse gas emissions. However, the assessment of EV penetration and the adoption of charging infrastructure was conducted based on government targets rather than relying on current data regarding the actual numbers and trends of EVs and chargers in Malaysia. The availability of accurate and up-to-date data on the number of EVs, their battery characteristics, chargers, and user charging behaviors in Malaysia would contribute to further enhancing this research work.

The decreasing availability of fossil fuels and their negative environmental impacts requires urgent need of developing renewable energy. The main objective of this research was to develop low-dimensional nanomaterials for harvesting solar and mechanical energy with high conversion efficiency. In particular, photoelectrochemical water splitting and photovoltaic cell applications driven by sunlight were investigated in this project. A highly efficient triboelectric nanogenerator was investigated for harvesting mechanical energy. The device was further integrated with an organic solar cell for harvesting both mechanical energy and solar energy. My research work started with the synthesis of nanostructured materials. Electrospinning, as well as electrospray, was developed to synthesise nanofibres and hollow hemispheres. The influences of processing parameters to the morphologies and structures of the nanomaterials were systematically investigated. An electrophoretic deposition method was also developed to form good-quality nanostructured metal oxide thin films, which were applied in photoelectrochemical water splitting. The metal oxide hollow hemisphere thin films were also applied in dye-sensitised solar cells. A transparent and flexible triboelectric nanogenerator was developed in order to harvest mechanical energy. The contact electrodes were created using metal nanowire percolation networks embedded in a polymer matrix. The correlation between the energy conversion performances and optical property of the triboelectric electrodes were comprehensively studied as a function of the areal fraction of the metal nanowires. A flexible hybrid cell, integrating the solar cell with the triboelectric device, was designed by constructing an organic solar cell under a single-electrode triboelectric nanogenerator. The hybrid cell could convert both solar and mechanical energies into electricity independently and simultaneously. Such devices are potentially able to supply electricity day and night. Nanomaterials offer novel approaches for enhancing the efficiency of harvesting solar and mechanical energy in a hybrid device.

A number of alternative economic and economic geography theories have been developed to account for the divergence of national political economy and industrial dynamics. These include the varieties of capitalism, developmental state, neo-Schumpeterian innovation, and Gerschenkronian catching-up theories. In this thesis I shall argue that in these theories a core and often shared concept of "institutional advantage" plays a central role in explaining different economic performances across nations. This concept is elaborated as a means of examining the causal relationships between institutional advantages and four necessary functions (market creation, capital mobilisation, process innovation and cost reduction) in the development of the photovoltaic (PV) industry of Germany, China, and South Korea. The development of these industries is examined in detail on the basis of empirical evidence in the form of archival and interview based data. Two main conclusions are reached. Firstly, domestic market creation is not a generally necessary condition for the development of a local PV industry at a national level. China's PV industry grew fast without a sufficient domestic market unlike in Germany. However, domestic market creation is important, because the domestic PV industry, national support policy and the domestic market are interrelated. Secondly, capital mobilisation is a core function in establishing the PV industry. In the 2000s, Korea failed to establish its local PV industry despite an institutional advantage in creating domestic markets, mainly due to the fact that it had an institutional disadvantage in mobilising capital. However, Germany and China succeeded in mobilising capital in their PV sectors, governments playing a decisive role in facilitating the raising of funds in both cases. This research contributes to a better understanding of the nature of industrial dynamics in the context of institutional configurations of a national political economy, broadening the usage of "institutional advantage" by applying this concept to comparative analysis on the national PV trajectories. Moreover, from the perspective of the social system, four necessary functions for the PV industry have been proposed and investigated.

Creating a diverse and flexible energy system to ensure security of supply is at the heart of UK energy policy. However, despite the apparent interest in the idea of securing supply in this way and the term ‘diversity' becoming more frequently used in this context in government White Papers, policy discourse and the academic literature relatively little attention has been given to exploring what diversity means, how it can be measured, what contribution it can make to different policy objectives and the specific implications for the UK electricity system. Furthermore CCS technologies which are becoming increasingly important to decarbonisation of the power sector in order to meet legally binding greenhouse gas targets set out in the Climate Change Act which raises the question, what are the potential impacts of these technologies on the diversity of the future UK electricity system? To answer this question a mixed methodology of quantitative energy-economic modelling (using MARKAL), scenario analysis and diversity analysis is combined with qualitative semi-structured stakeholder interviews. Data analysis is carried out in two parts. The first assesses the diversity (with a specific focus on the effect of different input assumptions on CCS technologies) of the scenarios generated using Stirling's Diversity Heuristic and creates a set of ‘diversity profiles' which map changes in diversity across each scenario. The second part uses stakeholder perspectives to inform the quantification of diversity across the same set of scenarios providing evidence of the impact of different stakeholder perspectives on the overall diversity of the electricity system.

Design and implementation of TCR (Thyristor Controlled Reactor) for industrial SVC (Static VAr Compensator) systems require special design. Both power stage and control system design and implementation are thoroughly investigated in this thesis. Engineering aspects of TCR design are emphasized and supported with case studies. As the first case study
a novel, unified and relocatable SVC for open cast lignite mining in Turkey is designed, implemented and commissioned. The second case study is the first 12 pulse TCR design and implementation for ladle furnace compensation in the world. The SVC simulation results are verified by data acquired in the field. Real time data are also simulated in EMTDC/PSCAD program to verify the control system responses of the commissioned systems.

ABSTRACT SENSORLESS DIRECT FIELD ORIENTED CONTROL OF INDUCTION MACHINE BY FLUX AND SPEED ESTIMATORS USING MODEL REFERENCE ADAPTIVE SYSTEM This work focuses on an observer design which will estimate flux-linkage and speed for induction motors in its entire speed control range. The theoretical base of the algorithm is explained in detail and its both open-loop, and closed-loop performance is tested with experiments, measuring only stator current and voltage. Theoretically, the field-oriented control for the induction motor drive can be mainly categorized into two types
indirect and direct field oriented. The field to be oriented may be rotor, stator, or airgap flux-linkage. In the indirect field-oriented control, the slip estimation based on the measured or estimated rotor speed is required in order to compute the synchronous speed. There is no need for the flux estimation in such a system. For the direct field oriented case the synchronous speed is computed with the aid of a flux estimator. In DFO, the synchronous speed is iv computed from the ratio of dq-axes fluxes. With the combination of a flux estimator and an open-loop speed estimator one can observe stator-rotor fluxes, rotor-flux angle and rotor speed. In this study, the direct (rotor) flux oriented control system with flux and-open-loop speed estimators is described and tested in real-time with the Evaluation Module named TMS320LF21407 and the Embedded Target software named Vissim from Visual Solutions Company.

This thesis proposes a method and develops a model for the participation of a combined cycle power plant to power system frequency control. Through the period of integration to the UCTE system, (Union for Coordination of Transmission of Electricity in Europe) frequency behavior of Turkey&rsquo
s grid and studies related to its improvement had been a great concern, so is the reason that main subject of my thesis became as &ldquo
Power System Frequency Control&rdquo
. Apart from system-wide global control action (secondary control)
load control loops at power plants, reserve power and its provision even at the minimum capacity generation stage, (primary control) are the fundamental concerns of this subject. The adjustment of proper amount of reserve at the power plants, and correct system response to any kind of disturbance, in the overall, are measured by the quality of the frequency behaviour of the system. A simulator that will simulate a dynamic gas turbine and its control system model, together with a combined cycle power plant load controller is the outcome of this thesis.

Technological improvements on wind energy systems with governmental supports have increased the penetration level of wind power into the grid in recent years. The high level of penetration forces the wind turbines stay connected to the grid during the disturbances in order to enhance system stability. Moreover, power system operators must revise their grid codes in parallel with these developments. This work is devoted to the modeling of variable speed wind turbines and the investigation of fault ride trough capability of the wind turbines for grid integration studies. In the thesis, detailed models of different variable speed wind turbines will be presented. Requirements of grid codes for wind power integration will also be discussed regarding active power control, reactive power control and fault ride through (FRT) capability. Investigation of the wind turbine FRT capability is the main focus of this thesis. Methods to overcome this problem for different types of wind turbines will be also explained in detail. Models of grid-connected wind turbines with doubly-fed induction generator and permanent magnet synchronous generator are implemented in the dedicated power system analysis tool PSCAD/EMTDC. With these models and computer simulations, FRT capabilities ofvariable speed wind turbines have been studied and benchmarked and the influences on the grid during the faults are discussed.

In this thesis, control schemes for the self-excited induction generator are developed with Matlab/Simulink. Self-excited induction generator is considered as a constant voltage-constant frequency supply for an isolated load. A wind turbine is assumed to be the variable-speed drive of the induction generator. Control schemes aim to ensure a constant voltage-constant frequency operation of the induction generator in case of the variations in the wind speed and/or the load. From the general model of the self-excited induction generator, the characteristics of the system and the dynamic responses of the system in case of any disturbance are examined. Next, the control strategies are developed both for the squirrel-cage rotor induction generator and for the wound-rotor induction generator. Two control loops are necessary for constant voltage-constant frequency operation of a variable speed induction generator, one for the voltage regulation and the other for the frequency regulation. After developing the control loops, constant voltage-constant frequency operation of the self-excited induction generator is simulated with a cage type saturation adaptive induction generator, a fixed capacitor with thyristor controlled reactor (TCR) used for frequency regulation and switched external resistors connected to the stator terminals used for voltage regulation.

This thesis analyses the necessity for the establishment, main functions and the viability of the Turkish Wholesale Electricity Trading and Contracting Company, TETAS in the short, mean and the long term. In order to understand the necessity for the establishment of TETAS, Turkish Energy Policies such as the state-led energy policies and the competition based market orientation are put under scrutiny. The thesis also discusses whether Turkish Government has carried out a comprehensive, deterministic and effective &ldquo
Liberalization Policy&rdquo
in the electricity sector by looking at the present situation and the principles outlined in Laws No: 4628, 5654 and 5686 and the Strategy Paper. The dissertation then examines the life span of TETAS by looking at the impacts of the strategy paper, liberalization procedure of the overall electricity market and newly enacted laws such as Law No: 5654 and 5686 in the short, mean and the long term. In addition, TETAS is examined whether it is a &ldquo
monopoly&rdquo
or not in Turkish Electricity wholesale market by calculating the supply concentration of TETAS using the Herfindahl Hirschman Index. Despite the studies on the establishment of the liberal market such as the envisagement of Law No: 4628 and the strategy paper, this thesis study envisages that it is still not possible to talk about a liberal electricity market. In addition, it is also concluded that the statements outlined in Laws No: 5654 and 5686 hinder the overall liberalization efforts since these laws are postponing the liberalization of electricity sector and making the life span of TETAS longer. As a result, liberalization efforts on the electricity market are unsuccessful in the mean term and TETAS seems to hold its dominance position in the wholesale market as a state-owned wholesale trading company in the long run.

Access to electricity is an important precondition to many aspects of human and economic development. Yet, in rural sub-Saharan Africa in particular, access rates remain very low — at an average of 17% and much lower in some cases. Rural electrification in Kenya, the focus of this thesis, had only reached 7% in 2014. Given the goal of universal electrification by 2030, formulated as part of Sustainable Development Goal 7, scalable and replicable approaches that are able to support productive and non-productive uses are required. Mini-grids are one promising solution to this problem, alongside grid extension and off-grid approaches such as solar home systems. However, their long-term operational sustainability has historically been a challenge. While the academic literature to date on sustainable energy access has largely been two-dimensional in its analysis of mini-grids (focusing on technology and economics or financing), this thesis contributes to an emerging body of recent contributions to the literature, which have begun to foreground socio-cultural considerations. Bridging the literature on collective action for common-pool resource (CPR) management and property rights theory, a refined theoretical framework is produced for the purpose of analysing the institutional conditions for sustainable management of rural mini-grids. The utility of this framework and of treating electricity in a mini-grid as a CPR is demonstrated via empirical analysis of three case studies of mini-grids in rural Kenya and evidence from 24 expert interviews. This yields insights on nontechnological approaches to addressing operational challenges relating to sustainable mini-grid management, e.g. fair allocation of limited amounts of electricity to different consumers in ways that are acceptable to the entire community. This thesis develops contributions to the literature on sustainable CPR management and collective action, property rights theory and energy access in developing countries. From these theoretical and empirical insights, it explores a novel institutional structure for sustainable management of pro-poor mini-grids in the form of a community–private property hybrid management platform, thereby opening up opportunities for future research into the implementation of such a platform. The thesis represents the first comprehensive attempt to analyse the institutional aspects of pro-poor mini-grid management as well as the first comprehensive attempt to treat electricity in a mini-grid as a CPR.

Abstract Objectives/Scope Kuwait Energy is exploring, developing, and operating four concessions located in the Western Desert and the Gulf of Suez in Egypt; the company implemented many projects that had a significant impact on saving operating expenses and reducing greenhouse emissions to preserve the environment. One of these recent executed projects was replacing scattered diesel generators with a Central gas-driven electric power grid in Al- Jahraa field in East Abu-Sennan concession. In this abstract, we present the challenges we faced during the planning phase and execution strategy applied to overcome these challenges. Methods Al-Jahraa Field includes 13 running wells, a waterflood station, and a main oil and gas production plant. The field electricity is supplied by 15 scattered diesel generators for wells and facilities, consuming 100,000 liters of diesel per month. During the feasibility study phase of the project, many challenges were faced which had a negative impact on the project’s economical assessment and that would result in cancelling the project, the challenges were summarized as following; the existence of wells at long distances from the site of the proposed main power station, which would require extending long lengths of electric power cables at a high cost, also the expected delay in the implementation and commissioning of the project resulting from the long delivery time of materials, especially copper cables and main switchgear during the COVID-19 pandemic. Several scenarios were studied for connecting the wells to the power station: The first scenario was to connect all wells and field facilities directly to the main power station. In this case, the estimated power cable lengths required to be extended were 25,000 Mt, in addition to using two 1 MW generators, one in service and the other would be a standby generator to provide backup power during a repair or maintenance service. This option economic model showed negative NPV due to the high cost of cables and extended execution time. Therefore, this option was cancelled. The second alternative was to connect each group of wells to three power stations to be operated using three diesel generators of 500 kVA for each station, with three backup generators. But the implementation of this option would lead to saving the cost of copper cables by 50%, but the cost of purchasing generators would increase due to the increase in the number of stations accordingly, in addition to the increase in operating expenses resulting from the increase in fuel consumption and maintenance cost compared to the first option. The third alternative, in which the economics of the project proved to be the best, is to divide the wells into three groups. Each of the two remote groups of wells are connected to an electric distribution panel, and then the two panels are connected by a main cable to the main power station. Moreover, the project cost was reduced by 50% due to the implementation of the following innovative optimization approach: Re-using ESP cables instead of copper cables optimized both cost and delivery time as these materials are pulled from ESP wells.These cables are designed for harsh downhole conditions increases its durability and extends its lifetime.Using step-up and step-down transformers enabled us to reduce cable sizing, which also reflected on the lower cost of the project and, accordingly, increased its feasibility to be constructed.An Incremental development approach, was followed in the management and implementation of the project, led to the speed of project delivery, and reduced the project risks and uncertainties. Results The project was completed and commissioned within the allocated budget and time frame, leading to: ○100% reduction of diesel fuel consumption levels.○+68% reduction in total emissions; emissions are reduced by 2.5tons per year on average.○reduced operational costs for each kilowatt hour generated due to using associated gas as fuel and releasing 13 rental generators.○With the replacement of 13 rental generators with just one, the amount of maintenance waste, such as batteries, used oil, oil filters, fuel filters, and so on, is significantly reduced.○These projects showed positive economic indicators (+NPV), with less than 1 years of payback. Conclusion From this project's planning, execution, and results, we can claim that if risk assessments, detailed scope of work, good resource and time management, and cost-effective choices were addressed carefully, shall result in outstanding performance. The design of a high-efficiency electrical power supply system and use of associated gas in power generation reduces levels of fuel consumption, GHG emissions, and operational costs. Power generation project is a repeated case performed in one of our own assets in Egypt due to positive results and are easily transferable to sister IOCs & NOCs.