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[en] The thesis deals with aspects of the competitiveness of bioenergy. The central aim is to develop a number of concepts that enables an extended analysis. The thesis is composed of four studies. In study 1 and 2 the emphasis is put on two institutional frameworks within the forest company, i.e. the framework around the forest fuel operations and the framework around the industrial timber operations. Depending on which of the two institutional frameworks that makes up the basis for the understanding of forest fuel operations, the forest fuel operations will be given different roles and different priorities. Different goals and the process of integrating the forest fuel operations into the forest company will therefore be carried out with different means, different feelings and different resources. Study 3 examines the conceptions that the actors of the energy system uphold. The study presents the concept of logic, which is an institutionalised conception of the competitiveness of bioenergy. Logics can be seen as the dominating conceptions within the energy system and are decisive in determining the factors and parameters that state the competitiveness of different forms of energy. Study 4 argues that the strategical work concerning the competitiveness of bioenergy in the long-run to a great extent is about understanding, shaping and utilising the conceptions that affect the bioenergy system. The study problematises strategies that are used to develop bioenergy by introducing the uncertainty of the future into the analysis. The uncertainty of the future is captured in different scenarios
[en] At present almost 43 percent of the waste heat of power plants in the FRG are emitted into surface waters. A deterministical waste heat simulation model for cooling ponds was developed, the results of which were compared with the directly taken water temperatures and the heat release coefficient at the Stever Dam near Haltern (Westfalia). The results of a rough calculation of the maximum cooling capacity of the inland waters of the FRG by means of the heat release coefficient amounted to a total of 336 Wsub(e) by exclusively applying the once-through cooling system. Preliminary tests are presented which are concerned with the effectivity of the heat release on water surfaces by covering them with floating polyhedron-shaped plastic materials to prevent at least part of the waste heat not taken up by rives or wet cooling towers. (GL)
[de]In der BRD werden z.Zt. 43% der KW-Abwaerme an Oberflaechengewaesser abgegeben. Es wurde ein deterministisches Abwaerme-Simulationsmodell fuer Kuehlteile entwickelt dessen Ergebnisse mit direkt an der Stever-Talsperre gemessenen Wassertemperaturen und des Waermeabgabekoeffizienten verglichen werden konnten. Eine ueberschlaegige Berechnung der maximal moeglichen Kuehlleistung bundesdeutscher Binnengewaesser ergab bei ausschliesslicher Anwendung der Durchlaufkuehlung einen Gesamtbetrag von 336 Wsub(e). Vorversuche werden dargestellt, das Waermeabgabevermoegen von Wasseroberflaechen durch Bedeckung mit schwimmenden Kunststoffkoerpern zu 'aktivieren', damit wenigstens ein Teil der Abwaerme nicht in die Fluesse oder Nasskuehltuerme geschickt wird. (GL)
[en] Market power in liberalised electricity markets dominated by hydropower is analyzed in four chapters. The existing literature on competition in hydropower markets is briefly presented and examined. Chapter 1 discusses the effects of market power in the context of acquisitions in a situation where transmission capacity is constrained. Chapter 2 and 3 elaborate on the issue of competition and market power when water inflow is uncertain, and finally Chapter 4 focuses on the supply function equilibrium model in the context of a hydropower market
[en] Climate change is one of the most challenging issues faced by humankind today. Scientific evidence regarding the existence of anthropogenic climate change was proven by the Intergovernmental Panel on Climate Change (IPCC). Based on the evidence, negotiations led to international agreements on the long-term stabilization of the climate system. In 2015, a limit on the global average temperature increase was set to 2°C, preferably 1.5°C, until 2100. To achieve this goal on a European scale, the EU agreed to reduce total greenhousegas (GHG) emissions by 80 to 95 % by 2050. Thereof, emission targets for individual sectors were derived. The effort is shared among member countries. Individual intermediate targets are being continually negotiated. However, a holistic plan that sets the pathway for implementing effective measures to achieve the GHG emission reduction targets in all sectors by 2050 is missing. It is expected that challenges to achieve the reduction will increase in the last twenty years due to the growing integration of variable renewable energy sources. In addition, anticipated demand shift from other sectors to the electricity sector and relatively strict reduction targets in the latter corroborate the priority to decarbonize the electricity sector. The cost-effective implementation of measures to achieve the GHG emission reduction targets requires a strategy based on optimal planning. Long-term economic depreciation of power plants and a radical technological change create a dynamic and a complex environment. Decisions taken on short-term scale affect the design of the electricity system on a long-term. Therefore, model-based studies help to unveil insights about the transition towards a decarbonized electricity supply and provide important information for planning of the future electricity system. Despite the large number of studies on the future of the electricity sector, cost-effective decarbonization pathways to achieve the GHG emission reduction goals are insufficiently explored. Successive transformation planning of the European electricity system is needed in order to achieve the GHG emission reduction targets by 2050. This thesis assesses cost-optimal decarbonization pathways for the European electricity sector to meet emission reduction targets by 2050. These pathways outline the transformation of the electricity supply infrastructure in successive 5-years increments until 2050. It includes investments in power plants, energy storage facilities, and the transmission system. For assessing these pathways, the multi-period, multi-region energy system model elesplan-m for European electricity sector was developed and used. This computer model is based on linear programming allowing the assessment of investment decisions constrained by technical and economic circumstances. These decisions are evaluated based on analyzing the electricity supply on an hourly scale for each reference year. The analyzed decarbonization pathways show that enormous effort is required to cut GHG emissions in the European electricity sector by 98 % by 2050 relative to 1990 levels. According to the investigated pathways, electricity generation by wind and photovoltaic (PV) power will meet the majority of the electricity demand by 2050. This requires 1,430 GW of wind power and 1,260 GW of PV power to be installed by 2050. Therefore, capacity of both technologies needs to be extended by approximately 40 GW on average per year. Enhanced international cooperation through the extension of cross-border transmission capacities allows a cost-effective implementation of climate protection measures in the electricity sector. The proposed electricity system design for 2050 includes 43 GW of pumped-hydro storage, 230 GW of battery energy storage systems, and 260 GW of power-to-gas (PtG) to balance supply and demand mismatches. Several sensitivity scenarios show that PtG is required to achieve climate change mitigation beyond the GHG reduction of 88 %. Carbon-intense electricity generation technologies, such as coal power, must be abandoned around 2035 to realize effective decarbonization. Cost of electricity supply is very likely to increase by approximately 60 % until 2050. The sensitivity scenarios show the cost increase only deviates by +/- 10 % relative to the reference case. If rising fuel prices, costs due to the impact of climate change, and other external costs would be incorporated in the cost of electricity supply, costs would be comparable to the expected cost increase of deploying renewables. Based on the results of this thesis, it can be concluded that a reliable political framework is required for a successful implementation of GHG reduction measures in the European electricity supply sector. A European-wide agenda to decarbonize the electricity sector allows cost-effective coordinated actions. A guaranteed reliable environment attracts investors to finance power plants, energy storage systems, and transmission system projects. Furthermore, it must be guaranteed that required technologies, i.e. power-to-gas, and manufacturing capacities for PV and wind power, are available. Immediate action is needed to realize climate change mitigation within the 2°C limits. Among other requirements, investments in coal power must be avoided and replaced by investments in renewable energy.
[en] With the aim to supply the energy-intense and highly industrialized economy of the Federal Republic of Germany more climate-friendly and crisis-safely with a larger contribution of homelike energy in the past years by the federal government a manifold of obligatory aims were composed. So for instance the greenhouse-gas emissions of 1990 shall be reduced against 2020 by 40 %. This shall be reached among others by an increased use of the renewable energies. But a transformation of these ambitionized aims seems from the present view only realistic, if in future all in Germany available options for the supply of current and heat from renewable energies are distinctly more intensively used. In front of the background of the geothermic potentials available in Germany the current and heat supply from deep geothermics is a very much promising option. But in 2012 only one facility and in 2013 three facilities have gone to the net. But against this a far-reaching usage of the geothermics in the context of the energy transition and the large heat and current production potentials in Germany is worth to be aspired. In front of the described problematics the aim of this work is to show how the system technics of the facilities for the usage of the deep underground for a current respectively heat production present themselves and how such complete facilities can be evaluated by means of technical, economical, and ecological characteristics. Base on the shown political aim settings it then shall be analyzed, how the calculated characteristics could change in future and whether the deep geothermics can provide an increasing contribution in the energy system of the future. The corresponding potential further developments are thereby analyzed regarding a short-termed (i. e. 2020) and an intermediate-termed (i. e. 2030) time horizon.
[en] In the course of the ongoing Energy Transition in Germany and Europe, the upcoming trend of decentralized generation leads to a new paradigm: Energy is more and more provided by a huge number of distributed energy resources instead of centralized generation. The share of cogeneration and Power-to-Heat solutions is growing. In combination with temporary electricity oversupply caused by a massive introduction of wind and photovoltaics this leads to a stronger sector coupling, especially regarding heat and power. Electric and thermal storage devices provide additional flexibility at central and decentral level that can be used to support the integration of renewables into the energy system. Whilst decentralization is the dominating trend in power and heat generation, on European level electricity market coupling is evolving leading to one single electricity market in Europe. These two contrary-appearing effects form the main playing field for this thesis: A Fundamental Electricity Market Model is developed, which allows for the simulation of a decentral oriented, but pan-European electricity market. With the developed model a co-simulation of centralized and decentralized generation is possible, considering the individual micro-economic objectives of the different market participants. A new decomposition approach derived from the concept of Lagrangian Relaxation forms the methodical core of the model. Beneath the coordination of the local load coverage within the different market areas, for the first time in parallel the international electricity exchanges are coordinated with Lagrangian Multipliers. This allows for an individual representation of thousands of generation units on central and decentral level, since the system overspanning optimization problem is decomposed into smaller sub-problems and a coordinator-problem. The model is validated against historic real data. A special attention is paid to the simulated electricity prices, the generation patterns of power plants and the results of the international electricity exchange. The correlation of realized and simulated electricity prices is about 90%. The ability of the model to simulate centralized generation in combination with a large amount of decentral energy resources on Prosumer level is demonstrated with scenario simulations for the year 2025. The simulations show that an investment in central Power-to-Heat facilities located at conventional CHP units to decrease (thermal) must-run generation dominates the decentral provision of flexibilities at Prosumer level regarding economic costs and the reduction of CO emissions.
[de]Der im Zuge der fortschreitenden Energiewende vorliegende Trend zu einer kleinteiligen Energieversorgung führt dazu, dass Energie immer weniger durch konventionelle Großkraftwerke, sondern vermehrt durch eine Vielzahl verteilter Energiewandlungseinheiten bereitgestellt wird. Ein zunehmender Einsatz von Kraft-Wärme-Kopplung und elektrischen Wärmeerzeugern führt in Kombination mit einem temporären Überangebot von Elektrizität aus Erneuerbaren Energien auf zentraler und dezentraler Ebene außerdem zu einer stärkeren Kopplung der Energieträger Strom und Wärme. Thermische und elektrische Speicher können in Kombination mit diesen Strom- und Wärmeerzeugern dazu genutzt werden, dem Strommarkt Flexibilität bereitzustellen. Während auf der Erzeugungsseite der Trend zur Kleinteiligkeit dominiert, schreitet auf europäischer Ebene die Ausweitung des internationalen Stromhandels kontinuierlich voran. Diese beiden gegensätzlich erscheinenden Trends bilden das zentrale Spannungsfeld dieser Arbeit. Es wird ein fundamentales Strommarktmodell entwickelt, welches die Simulation eines dezentral geprägten, jedoch europaweit verbundenen Strommarktes ermöglicht. Das entwickelte Modell ermöglicht die detaillierte Abbildung einer Vielzahl von zentralen und dezentralen Erzeugungsanlagen unter Berücksichtigung deren individueller mikroökonomischer Zielfunktionen im internationalen Strommarkt. Den methodischen Kern bildet ein neuartiges Dekompositionsverfahren in enger Anlehnung an die Lagrange Relaxation. Neben der Koordination der lokalen Lastdeckungsaufgabe innerhalb eines Marktgebietes wird erstmals auch die internationale Marktkopplung und mithin die Bestimmung der Austauschleistungen im internationalen Stromhandel in den iterativen Lagrange Koordinationsprozess integriert. Dies ermöglicht die individuelle Abbildung einer sehr großen Anzahl verschiedenster Energiewandlungseinheiten. Das entwickelte Modell wird anhand realer Daten validiert. Dabei liegt der Fokus der Bewertung auf den simulierten Strompreisen, dem Einspeiseverhalten der Kraftwerke und den Ergebnissen des internationalen Stromhandels. Die Korrelation zwischen realen Day-Ahead Spotpreisen und simulierten Strompreisen beträgt ca. 90%. Die Fähigkeit des Modells zur gleichzeitigen Abbildung einer großen Anzahl Prosumer und des zentralen Kraftwerksparks wird anhand von Szenariorechnungen für das Jahr 2025 demonstriert. Diese belegen, dass zentrale Power-to-Heat Lösungen zur Flexibilisierung des zentralen Kraftwerksparks (Reduzierung des sogenannten „Must-Run Sockels“) CO-Einsparungen zu wesentlich geringeren volkswirtschaftlichen Kosten ermöglichen als die dezentrale Bereitstellung von Flexibilitäten im Haushaltssektor.
[en] Models that can describe the behavior of a lithium-ion battery are indispensable for product development as well as for the reliable control of the battery operation by a battery management system. In this work a model is developed, parametrized and validated that can predict the electric behavior of a lithium-ion cell throughout its entire lifetime.
[de]Modelle, die das Verhalten einer Lithium-Ionen Batterie beschreiben können, sind sowohl für die Produktentwicklung als auch für die zuverlässige Steuerung des Batteriebetriebs durch ein Batteriemanagementsystem unabdingbar. In dieser Arbeit wird ein Modell entwickelt, parametriert und validiert, das in der Lage ist, das elektrische Verhalten einer Lithium-Ionen Zelle während ihrer gesamten Lebensdauer zu prädizieren.
[en] The object of this thesis is to evaluate the effects of river regulation on riparian flora in boreal rivers, and to increase the understanding of the processes causing patterns in species diversity. Comparisons of free-flowing and regulated rivers showed that regulated rivers have fewer plant species and less plant cover per 200-m-stretch of river margin. Regulated river-margins were less species-rich compared to free-flowing rivers irrespective of the type of regulated water level regime, except for unimpounded reaches downstream of dams. Species with good dispersal capacity (wind-dispersed or long-floating species) were least affected by regulation, showing that the ability to recolonize after local extinction is an important character. The temporal development of river-margin vegetation in regulated rivers was studied by investigating differently-old reservoirs and impoundments. Plant-species richness along storage reservoirs increased during the first 30-40 years following damming, but declined thereafter. Both species richness and plant cover remained impoverished compared to free-flowing rivers about 70 years after regulation. Along run-of-river impoundments, plant species richness and cover peaked after 10-20 years. In the long run, riparian species richness was lower, but riparian species density did not differ, compared to free-flowing rivers. Dams fragment the riparian flora. Adjacent run-of-river impoundments developed different riparian floras, probably because dams are barriers to the dispersal of species with poor floating ability. This shows that dams disrupt the ecological continuity not only for the river channel, but also for the adjoining riparian corridor. The number of species and genera were similar between river margins along boreal free-flowing rivers in Europe and North America. The riparian floras shared few species but many genera and families. The regional species pools were similar-sized and composed of species with similar traits, and the species-area relationship did not differ between continents. Moreover, the effects of river regulation were similar between the continents. The last paper explores the evolutionary consequences of changes in species' geographical distributions in response to orbitally-forced climatic shifts on time-scales of 10-100 kyrs. Species' range-dynamics decreases gradual speciation rates, increases species' geographical range-sizes, increases the proportion of species formed by abrupt speciation (mainly polyploidy), and selects against high specialization and low vagility. This leads to species having low specialization and high vagility in areas with large range-dynamics. This curbs gradual speciation rates further, but buffer against extinction
[en] A reliability programming model was developed to consider the uncertainty in inflows and energy demands in planning the operation of single or multipurpose water reservoirs. The model was also designed to evaluate the hydrologic risks as a measure of the system not being able to satisfy the storage requirements for hydropower generation and flood control. The model determines the optimal levels of risk by trading off the total benefits accrued from the operation with the economic losses which may be incurred as a consequence of these risk levels. Direct implementation of the reliability model was found to be limited by the assumption of independence between monthly reservoir inflows, which tends to lead to conservative planning of the operation of reservoirs. Three new approaches were proposed to alleviate the problem of conservative planning, thus making the model a robust tool for planning purposes. Application and practical implementation of the reliability model were demonstrated in a case study for Manitoba Hydro. refs., figs
[en] In this work, new methods for characterizing the electrochemical and thermal behavior of lithium-ion cells are presented. Based on these, a modeling approach is presented that is able to represent the cell behavior in four domains (static and dynamic for electrochemical and thermal behavior) separately. This enables transferability to a wide range of material chemistries, scalable accuracy and parameterization that can be automated.
[de]In dieser Arbeit werden neue Verfahren zur Charakterisierung des elektrochemischen und thermischen Verhaltens von Lithium-Ionen Zellen vorgestellt. Basierend auf diesen wird ein Modellansatz vorgestellt, der das Zellverhalten in vier Domänen (statisch und dynamisch für elektrochemisches und thermisches Verhalten) getrennt abzubilden vermag. Hierdurch wird die Übertragbarkeit auf verschiedenste Materialchemien, skalierbare Genauigkeit und eine automatisierbare Parametrierung möglich.