Die ständige Verfügbarkeit der „Edelenergie“ Strom wird von Wirtschaft und Haushalt als selbstverständlich vorausgesetzt. Mit dem Einbinden von immer mehr dezentralen Stromerzeugern, die Strom vor allem aus regenerativen Energieträgern erzeugen, muss die Fahrweise des auf große zentrale Kraftwerke orientierten Elektroenergiesystems überdacht werden. Eine dabei mögliche Strategie können „virtuelle Kraftwerke“ (VKW) sein, die als ein intelligenter Verbund kleinerer Einheiten in zentrale Systeme eingefügt werden können. Dabei treten technische und organisatorische Probleme auf, die im vorliegenden Beitrag aus der Sicht der Forschungsergebnisse eines DFG-Graduiertenkollegs behandelt werden. / The uninterrupted availability of electric power is taken for granted by industrial and household users. The strategy for operation of a centralised power system based on high-capacity power stations, however, needs to be revised, as more and more decentralised units, above all installations using renewable resources, are integrated into the system. “Virtual power plants” (VPP), where several smaller power generators of different types are managed as a whole, are able to contribute to a new strategy. This paper reports on some of the technical and organisational problems which have been solved through the research work of a graduate college of the German Research Foundation (DFG).

Das „CO2-freie“ Kraftwerk ist in den Medien ein viel strapaziertes Schlagwort. Dieser Beitrag zeigt, welche Anstrengungen derzeit unternommen werden, um das Hauptreaktionsprodukt der Braunkohlenverbrennung, das Kohlendioxid, nicht in die Atmosphäre abzugeben, sondern es für eine unterirdische Lagerung aufzubereiten, welche Strategien dabei verfolgt und Technologien bemüht werden müssen und dass „CO2-frei“ noch lange nicht CO2-frei ist. Erforschen, Beherrschen und Gestalten von Verbrennungsvorgängen mit reinem Sauerstoff, Nachempfinden mittels Simulation, Behandlung und Reinigung der dabei entstandenen Rauchgase und die Zusammenführung dieser Teilschritte zu einer stimmigen, effektiven Prozesskette sind Aufgaben, die es unter der Maßgabe der Sicherung eines bezahlbaren Strompreises zu lösen gilt. / The ‘CO2-free’ power station is a frequently encountered keyword in the media. This paper highlights the efforts which are being undertaken at TU Dresden to avoid carbon dioxide emissions into the atmosphere and, instead, to store it safely under ground. The handling of combustion with pure oxygen, simulation of the processes and cleaning of the exhaust gases are steps which need to be linked into a functional process chain for further evaluation. It is shown that this research is necessary in order to keep ‘CO2-free’ electricity affordable.

Die absorptive Gasreinigung ist eine gute Möglichkeit, um den CO2-Ausstoß von Kraftwerken zu senken. In diesem Beitrag werden das neue Waschmittel GenosorbN und die Ergebnisse erster damit durchgeführter Versuchsreihen vorgestellt. Es wird diskutiert, welche CO2- Abscheiderate zukünftig angestrebt werden sollte. / Absorptive gas purification is one good possibility to reduce the CO2 output of a power station. This contribution presents the new absorbent GenosorbN, with the results of initial experimental series. The degree of elimination to be targeted for the future is discussed.

Die Entflechtung der Netze von den liberalisierten Bereichen der Energieversorgungsunternehmen (EVU) spiegelt sich in der Staatsaufsicht wider: Die liberalisierten Tätigkeitsbereiche werden dem freien Spiel der Kräfte ausgesetzt und unterliegen im Falle von Marktmacht der kartellrechtlichen Missbrauchsaufsicht. Demgegenüber wird der Netzbetrieb vollumfänglich und ausschließlich durch die Regulierungsbehörden überwacht. Trotz wesentlicher Unterschiede haben beide Formen der Staatsaufsicht die Funktion, unternehmerisches Handeln derart zu lenken, dass ein effektiver Wettbewerb im Energiemarkt möglich ist. Mit dem Ziel der Wettbewerbsförderung wird das Energierecht ständig Reformplänen unterzogen, ohne dass der Verordnungsgeber bereits bestehenden Konkretisierungsaufträgen umfassend nachkommen konnte. Unter Berücksichtigung der ausstehenden Rechtsverordnungen müssen Reformen ein angemessenes Verhältnis von staatlicher Steuerung und unternehmerischer Freiheit beachten. / Government supervision reflects the ongoing segregation of the distribution networks from the liberalised sectors of the power supply industry: The latter are exposed to full competition and are subject to the control of abusive practices by competition authorities. The networks, however, are controlled fully and exclusively by regulatory authorities. Despite their substantial differences, both forms of supervision are aimed at directing business activities to ensure effective competition on the energy markets. To promote competition, energy law is undergoing constant reform, but the required ordinances are yet to be enacted. New reform ideas should consider the outstanding ordinances and maintain an appropriate balance between government supervision and corporate freedom.

The world has an imperative need to switch to clean and renewable energy sources. Effectively harnessing the vast energy that radiates on the earth's surface from the sun is a long standing goal of clean energy proponents. This work introduces the novel concept of a solar energy belt stretched across America. The thesis provides the first steps towards showing that not only can such a belt be built, but it can effectively yield a substantial quantity of America's energy in a cost effective fashion. In order to maximize impact of the work, a general mathematical model is first derived that may be extended by any interested party. The model is then viewed from the perspective of mathematical combinatorics and is thus made subject to combinatorial optimization. Genetic Algorithms are used for this optimization scheme. A GUI and simulation is provided that demonstrates the evolution of the solar belt solution in real-time. Results are demonstrated.

The design, construction and testing of a reverse-osmosis (PV-RO) desalination system for fresh water shortage area is presented. The system operates from salt water or brackish water and can be embedded in a renewable energy power supply system, since many fresh shortage areas are remote and isolated. Special attention is given to the energy efficiency of small-scale reverse osmosis desalination systems. Limitations of conventional control strategy using toggle control are presented. Based on this, an objective of creating a small-scale reverse osmosis desalination system was set out. Initially, the background information is presented. This includes the natural resources crisis and main desalination technologies and the viability of the integration with renewable energy source. A reverse osmosis (RO) desalination system was assembled and set up at the Curtin University of Technology, Perth, Western Australia Supervisor Control And Data Acquisition (SCADA) system was built using a Human Machine Interface software and a programmable logic controller (PLC). Instrumentation that included signal conditioners was made in analysis of the system characteristics. Initial testing of the system was conducted after the system design and configuration was accomplished. Testing results were used as a guideline for the development of the whole system. / Modelling and simulation of the system components in MATLABSimulink is presented, together with a discussion of the control systems modelling and design procedure, in which the aim was to improve the efficiency of the reverse osmosis system. Simulations show the designed reverse osmosis system with Proportional Integral and Derivative (PID) controller has better performance than other controllers. This consequently leads to a lower overall cost of the water, as well as reducing full maintenance cost of the electric drives in the reverse osmosis unit. Additionally, the configuration of the remote control system through General Package Radio System (GPRS) network is depicted. After the PID control algorithm was programmed into the Programmable Logic Controller (PLC), system experiments were carried out in short durations and long durations. System performance was monitored and experimental results prove that the new control strategy applied increase the water productivity and is able to improve the system efficiency up to 35%. Based on the data obtained from the simulations and experiments, Mundoo Island was chosen to be the location for a case study. The electric load profile of the island was derived from the Island Development Committee in Mundoo. / A water demand profile was created and modelled in Matlab to be the input of the reverse osmosis system. The electric load of the reverse osmosis system was generated from Matlab simulation. This result was entered in Hybrid Optimisation Model for Electric Renewables (HOMER) simulator. Having the designed RO unit as one of the electric loads, the entire remote area power supply (RAPS) system was tested in simulations which shows the energy cost is AUS$0.174 per kWh, lower than the Island Development Committee budget estimation of AUS$0.25 per kWh. The cost of the water treatment is very promising at AUS$0.77 per m3.

The dissertation presents a generalized control structure for two-stage power converters operated in a renewable energy power system for smart grid and micro grid systems. The generalized control structure is based on the two-loop average-mode-control technique, and created by reconstructing the conventional control structure and feedback configuration. It is broadly used for both dc-dc and dc-ac power conversion based on the two-stage converter architecture, while offering several functionalities required for renewable energy power systems. The generalized control structure improves the performance and reliability of renewable energy power systems with multiple functionalities required for consistent and reliable distributed power sources in the applications of the smart grid and micro grid system. The dissertation also presents a new modeling approach based on a modification of the subsystem-integration approach. The approach provides continuous-time small-signal models for all of two-stage power converters in a unified way. As a result, a modeling procedure is significantly reduced by treating a two-stage power converter as a single-stage with current sinking or sourcing. The difficulty of linearization caused by time-varying state variables is avoided with the use of the quasi-steady state concept. The generalized control structure and modeling approach are demonstrated using the two-stage dc-dc and dc-ac power conversion systems. A battery energy storage system with a thermoelectric source and a grid-connected power system with a photovoltaic source are examined. The large-signal averaged model and small-signal model are developed for the two demonstrated examples, respectively. Based on the modeling results, the control loops are designed by using frequency domain analysis. Various simulations and experimental tests are carried out to verify the compensator designs and to evaluate the generalized control structure performance. From the simulation and experimental results, it is clearly seen that the generalized control structure improves the performance of a battery energy storage system due to the unified control concept. The unified control concept eliminates transient over-voltage or over-current, extra energy losses, power quality issues, and complicated decision processes for multiple-mode control. It is also seen that the generalized control structure improves the performance of a single-phase grid-connected system through increased voltage control loop bandwidth of the active ripple current reduction scheme. As a result of the increased loop bandwidth, the transient overshoot or undershoot of the dc-link voltage are significantly reduced during dynamic load changes. / Ph. D.

The declining cost of photovoltaic (PV) modules has enabled the vision of ubiquitous photovoltaic (PV) power to become feasible. Emerging PV technologies are facilitating the creation of intentionally non-flat PV modules, which create new applications for this sustainable energy generation currently not possible with the traditional rigid, flat silicon-glass modules. However, since the photovoltaic cells are no longer coplanar, there are significant new requirements for the power electronics necessary to convert the native form of electricity into a usable form and ensure maximum energy harvest. Non-uniform insolation from cell-to-cell gives rise to non-uniform current density in the PV material, which limits the ability to create series-connected cells without bypass diode or other ways to shunt current, which is well known in the maximum power tracking literature. This thesis presents a modeling approach to determine and quantify the variations in generation of energy due to intentionally non-flat PV geometries. This will enable the power electronics circuitry to be optimized to harvest maximum energy from PV pixel elements – clusters of PV cells with similar operating characteristics. This thesis systematically compares different geometries with identical two-dimensional projection "footprints" for energy harvest throughout the day. The results show that for the same footprint, a semi-cylindrical surface harvests more energy over a typical day than a flat plate. The modeling approach is then extended to demonstrate that by using non flat geometries for PV panel, the availability of a remotely located stand-alone power system can be increased when compared to a flat panel of same footprint. These results have broad application to a variety of energy scavenging scenarios in which either total energy harvested needs to be maximized or unusual geometries for the PV active surfaces are required, including building-integrated PV. This thesis develops the analysis of the potential energy harvest gain for advanced non-planar PV collectors as a necessary first step towards the design of the power electronics circuits and control algorithms to take advantage of the new opportunities of conformal and non-flat PV collectors.

This diploma thesis deals with the issue of accumulation of electricity produced by renewable sources. The first part focuses on the description of possible ways of accumulation, especially with focus on those methods, that are suitable for renewable energy sources. The next part deals with the design of the accumulation energy in the compressed air for the selected photovoltaic power plant. The necessity of designing a particular method of energy storage, is also its technical and economic analysis, which is the content of the last part of the thesis.

Indonesia launched a sovereign green sukuk in 2018 to fund green projects that can contribute to addressing climate change and achieving the Sustainable Development Goals. This issuance also marked  the first sovereigngreen sukuk issuance in the world. Since then, Indonesia has issued five sovereign green sukuks and has mobilized 3.23 billion USD from these issuances. The money raised from these sovereign green sukuks has been directed to five eligible sectors: sustainable transportation, energy efficiency, renewable energy, waste toenergy and waste management, and resilience to climate change for disaster risk areas. This study aims to assess firstly how the money raised by the Indonesian sovereign green sukuk flows to the renewable energy powerplant projects. Secondly, this research also aims to identify what kind of barriers influence the flows of greensukuk money to the renewable energy power plant projects. A literature review is carried out to outline the barriers that have been known to exist in green bond and green sukuk financial flows from the previous research. Meanwhile, an exploratory single case study is employed to explore the flow of money and identify the barriersin Indonesia. The findings were analyzed using thematic analysis.   Results show that there are two key actors in implementing the flow of money: the Ministry of Finance and the Ministry of Energy and Mineral Resources. The Ministry of Finance has a role as an issuer of the sovereigngreen sukuk. On the other hand, The Ministry of Energy and Mineral Resources has a role as the project ownerin the renewable energy sector. Therefore, it requires good coordination between them since each ministry hasdifferent responsibilities and priorities. Meanwhile, there are three frameworks that determine the mechanismof the flow of finance. Firstly, the state budget. Secondly, the Law No. 19/2008 concerning Sovereign Sukuk and its subordinate legislation, which is the Government Regulation No. 56/2011 concerning Project Financingthrough Sovereign Sukuk Issuance. Lastly, the Republic of Indonesia Green Bond and Green Sukuk Framework.The involvement of these frameworks shows that the implementation of the sovereign green sukuk must alignto the management of the state budget, must be compliant with the sovereign sukuk law and its subordinate legislation, and must follow the green principles according to the Republic of Indonesia Green Bond and Green Sukuk Framework. This study also shows two main barriers: the lack of coordination between ministries and the lack of capacity in some of the regional governments. The lack of coordination between ministries has affected the formulation of the impact report. Since the impact report is one of the key components in the sovereign green sukuk, the delay in delivering the impact report and the lack of quality in providing theinformation in the impact report can diminish the investor’s confidence. Meanwhile, the lack of capacity insome of the regional governments to manage and operate the renewable energy power plants funded by the green sukuk has led these projects could not give the impact as expected in reducing emission and achieving the SDGs target in the rural areas.   Based on these results, this study suggests these recommendations: (1) The Ministry of Finance should consider establishing a directorate dedicated to exclusively handling green finance; (2) The ministries that own the projects should raise their awareness in reporting the impact of the green projects; (3) The coordination between the ministries should be improved in ensuring solid implementation in the issuance, allocation, and reporting phase; (4) The Ministry of Energy and Mineral Resources should ensure that the plan to build renewable energypower plants from the green sukuk are well-planned and well-executed. (5) The regional governments should increase their technical and financial capacity to ensure the sustainability of the renewable energy power plantsthey manage.