This thesis develops and applies methodological approaches for the analysis of intraday markets for electricity which are organised as continuous double auctions. The focus is to improve the understanding of how balancing forecast errors from weather-dependent renewable energy sources influences the outcomes of continuous intraday markets. This is important as it helps to assess how large amounts of renewable capacity can be utilised cost-efficiently and without stressing security of supply. In a first step, the thesis proposes a (non-mathematical) model of a continuous intraday market to show how the direction of the forecast error determines transactions between market participants, how these transactions relate to the formation of prices, and how the market integration of renewables can be improved. In a second step, the thesis provides a foundation for quantitative market analyses by modelling price-setting decisions for power generators and electricity demanders. This makes it possible to show that information on market participants' technical characteristics enables informed predictions of their market behaviour. In a third step, the thesis presents a computer simulation of a continuous intraday market. Implementing the simulation approach for the German power system allows calculation of the costs associated with the uncertain feed-in from renewables.

In this thesis current questions regarding the functionality of liberalized electricity markets are studied addressing different topics of interest in two main directions: market power and competition policy on electricity wholesale markets, and network investments and incentive regulation. The former is studied based on the case of the German electricity market with respect to ex-post market power analysis and ex-ante remedy development. First an optimization model is designed to obtain the competitive benchmark which can be compared to the observed market outcomes between 2004 and 2006. In a second step the horizontal breaking up of dominant firms (divestiture) is simulated applying equilibrium techniques (the classical Cournot approach and the Supply Function Equilibrium approach). The later issue of transmission capacity investment is addressed by highlighting the complexity of network investments in electricity markets and by analyzing a regulatory mechanism with a two part tariff approach. The technical characteristics of power flows are combined with economic criteria and tested for different network settings.

This dissertation focuses on selected aspects of network congestion arising in liberalized electricity markets and their management methods with a special weight placed on the integration of increased renewable generation in Europe and Germany. In a first step, the theoretical concepts of congestion management are introduced complemented by a review of current management regimes in selected countries. In the second step, the European approach of managing congestion on international as well as national transmission links is analyzed and the benefits of an integrated congestion management regime are quantified. It is concluded that benefits can be achieved by a closer cooperation of national transmission system operators (TSOs). Thirdly, the German congestion management regime is investigated and the impact of higher renewable generation up to 2020 on congestion management cost is determined. It is shown that a homogeneous and jointly development of generation and transmission infrastructure is a prerequisite for the application of congestion alleviation methods and once they diverge congestion management cost tend to increase substantially. Lastly, the impact of intermittent and uncertain wind generation on electricity markets is analyzed. A stochastic electricity market model is described, which replicates the daily subsequent clearing of reserve, dayahead, and intraday market typical for European countries, and numerical results are presented.

This dissertation focuses on selected aspects of network congestion arising in liberalized electricity markets and their management methods with a special weight placed on the integration of increased renewable generation in Europe and Germany. In a first step, the theoretical concepts of congestion management are introduced complemented by a review of current management regimes in selected countries. In the second step, the European approach of managing congestion on international as well as national transmission links is analyzed and the benefits of an integrated congestion management regime are quantified. It is concluded that benefits can be achieved by a closer cooperation of national transmission system operators (TSOs). Thirdly, the German congestion management regime is investigated and the impact of higher renewable generation up to 2020 on congestion management cost is determined. It is shown that a homogeneous and jointly development of generation and transmission infrastructure is a prerequisite for the application of congestion alleviation methods and once they diverge congestion management cost tend to increase substantially. Lastly, the impact of intermittent and uncertain wind generation on electricity markets is analyzed. A stochastic electricity market model is described, which replicates the daily subsequent clearing of reserve, dayahead, and intraday market typical for European countries, and numerical results are presented.

This dissertation focuses on selected aspects of network congestion arising in liberalized electricity markets and their management methods with a special weight placed on the integration of increased renewable generation in Europe and Germany. In a first step, the theoretical concepts of congestion management are introduced complemented by a review of current management regimes in selected countries. In the second step, the European approach of managing congestion on international as well as national transmission links is analyzed and the benefits of an integrated congestion management regime are quantified. It is concluded that benefits can be achieved by a closer cooperation of national transmission system operators (TSOs). Thirdly, the German congestion management regime is investigated and the impact of higher renewable generation up to 2020 on congestion management cost is determined. It is shown that a homogeneous and jointly development of generation and transmission infrastructure is a prerequisite for the application of congestion alleviation methods and once they diverge congestion management cost tend to increase substantially. Lastly, the impact of intermittent and uncertain wind generation on electricity markets is analyzed. A stochastic electricity market model is described, which replicates the daily subsequent clearing of reserve, dayahead, and intraday market typical for European countries, and numerical results are presented.

This thesis develops and applies methodological approaches for the analysis of intraday markets for electricity which are organised as continuous double auctions. The focus is to improve the understanding of how balancing forecast errors from weather-dependent renewable energy sources influences the outcomes of continuous intraday markets. This is important as it helps to assess how large amounts of renewable capacity can be utilised cost-efficiently and without stressing security of supply. In a first step, the thesis proposes a (non-mathematical) model of a continuous intraday market to show how the direction of the forecast error determines transactions between market participants, how these transactions relate to the formation of prices, and how the market integration of renewables can be improved. In a second step, the thesis provides a foundation for quantitative market analyses by modelling price-setting decisions for power generators and electricity demanders. This makes it possible to show that information on market participants' technical characteristics enables informed predictions of their market behaviour. In a third step, the thesis presents a computer simulation of a continuous intraday market. Implementing the simulation approach for the German power system allows calculation of the costs associated with the uncertain feed-in from renewables.

This dissertation focuses on selected aspects of network congestion arising in liberalized electricity markets and their management methods with a special weight placed on the integration of increased renewable generation in Europe and Germany. In a first step, the theoretical concepts of congestion management are introduced complemented by a review of current management regimes in selected countries. In the second step, the European approach of managing congestion on international as well as national transmission links is analyzed and the benefits of an integrated congestion management regime are quantified. It is concluded that benefits can be achieved by a closer cooperation of national transmission system operators (TSOs). Thirdly, the German congestion management regime is investigated and the impact of higher renewable generation up to 2020 on congestion management cost is determined. It is shown that a homogeneous and jointly development of generation and transmission infrastructure is a prerequisite for the application of congestion alleviation methods and once they diverge congestion management cost tend to increase substantially. Lastly, the impact of intermittent and uncertain wind generation on electricity markets is analyzed. A stochastic electricity market model is described, which replicates the daily subsequent clearing of reserve, dayahead, and intraday market typical for European countries, and numerical results are presented.

The thesis is devoted to magnetic metamaterials operating in the frequency range of 10 MHz 1 GHz. Mechanisms of tailoring the properties of metamaterials are developed and a number of linear and nonlinear applications is proposed.In Chapter 1, the introduction to the field of metamaterials is given and the main goal of the thesis is defined as the search for possible applications of low-frequency metamaterials. The main motivation is the potential of magnetic metamaterials in Magnetic Resonance Imaging (MRI).Chapter 2 briefly summarizes the near-field properties of magnetic metamaterials. Magnetic coupling between a pair of metamaterial elements is described and magnetoinductive (MI) waves propagating on the metamaterials arrays are introduced.In Chapter 3, the magnetic coupling between the elements is studied in more detail. Based on the analogy between MI waves and acoustic waves in solids, "diatomic" metamaterial arrays having two elements per unit cell are introduced. It is shown that by changing the resonant frequencies of the elements and the coupling between them it is possible to acquire additional freedom in tailoring the dispersion properties of MI waves compared to simple "monatomic" configurations.In Chapter 4, various linear applications of metamaterials are discussed. They are shift-dependent transmission, subwavelength imaging and focusing, and rotational resonance of MI waves. It is shown that the microscopic model based on taking the interaction between the elements into account allows for reliable explanation of the phenomena studied.In Chapter 5, a nonlinear application, parametric amplification of MI waves, is discussed. It is shown that parametric amplification can lead to the compensation of loss in metamaterials and to increase of the power extracted from an MRI detection system.Conclusions are drawn and possible directions for future work are determined in Chapter 6.

Metallhalogenid-Perowskite (MHPs) sind Halbleiter, die einzigartige photophysikalische Eigenschaften aufweisen, die sie ideal für photovoltaische Anwendungen machen. Techniken werden kontinuierlich entwickelt, um die Leistungsgrenzen der Perowskite weiter zu verschieben. Dennoch weisen diese Materialien verschiedene Herausforderungen auf. Zu diesen gehören eine geringe Stabilität unter einer Vielzahl von äußeren Bedingungen, sowie eine große Diskrepanz zwischen den Wirkungsgraden von Geräten im Labormaßstab und großflächigen Geräten. Zunächst wurden mit Hilfe von Photolumineszenz-Spektroskopie Ladungsübertragungsmechanismen zwischen MHPs und atmosphärischen Gasen untersucht, um deren Einfluss auf die Materialstabilität zu bestimmen. Durch den Vergleich der Emission von verschiedene MHP wurde die Wirkung untersucht, die atmosphärische Gase auf Grenzdefekte im Material haben. Diese Löschungseffekte wurden nachfolgend mit dem Stern-Volmer-Modell analysiert. Es stellte sich heraus, dass ein Teil von der Gase bindet jedoch an die MHPs, wobei teilweise Kristalldefekte passiviert werden und für jedes der Gase Ladungstransfermechanismen vorgeschlagen wurden. Zweitens wurde die Skalierung von MHP-Bauelementen mittels Tintenstrahldruck untersucht. Dazu wurden drei Kristallisationstechniken ausgewertet. Eine davon verwendete eine sequenzielle Abscheidung von zwei Präkursortinten, während die beiden anderen kristallisierte Tinten verwendeten, die in einem Schritt abgeschieden wurden. Die letztgenannten Techniken verwendeten beide niedrige Drücke und bei einer wurde ein kontrollierter Stickstoffstrom auf die Probe angewendet. Solarzellen mit einer Effizienz von 16,8% auf einer Fläche von 0,16 cm² wurden demonstriert. Diese Ergebnisse zeigen ein neuartiges Verfahren zur Untersuchung von strahlungslosen Verlustwegen in MHPs auf. Zusätzlich demonstrieren diese Studien, dass der Tintenstrahldruck eine geeignete Technologie ist, um MHP-Bauelemente zu skalieren. / Metal halide perovskites (MHPs) are semiconductor materials that show unique photophysical properties, making them ideal for photovoltaic applications. Having shown power conversion efficiencies of up to 25.5%, techniques are continuously being developed to push perovskites to unprecedent limits. Yet, these materials present challenges like a low stability under a variety of conditions as well as a large disparity between the efficiencies of lab scale and large area devices. This thesis addresses these two major obstacles. First, charge transfer mechanisms between MHPs and atmospheric gases were studied to determine their effect on the material stability by using photoluminescence spectroscopy. By comparing the emission of MHPs, the effect that molecular oxygen, nitrogen, argon, and water have on boundary defects in the material was studied. These quenching effects were later analyzed using the Stern-Volmer model. It was found that the gases bounce off the surface, but a portion of them bind to the MHPs, in occasions passivating defects on the crystals. Using these results, charge transfer mechanisms were proposed for each one of the gases. Second, scaling of MHP devices was examined using inkjet printing. For this, three crystallization techniques were evaluated. One of them used sequential deposition of two precursor inks, while the other two crystallized ink that was deposited in one step. Both latter techniques used low pressures, below 1 mbar, and only one of them applied a controlled stream of nitrogen to the sample. Using these techniques, the deposition of a 15x15 cm² area as well as a device with an efficiency of 16.8% on an area of 0.16 cm² were demonstrated. These results show a novel procedure to study non-radiative loss paths in MHPs to enhance their stability and performance as devices. Also, they show that inkjet printing is a favorable technology to scale MHP devices and eventually facilitate the mass production of this type of photovoltaic devices.

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