The power balance of an electrical power system is crucial to the quality of the delivered electricity as well as the security of supply. In a scenario where Swedish nuclear power plants are being phased out and replaced by renewable energy sources new constraints are added to the power balance equation since the production of many renewable energy sources, such as wind and solar power, are intermittent by nature. This leads to a situation where the currently available regulating power might have difficulties to manage the increasing frequency fluctuations in the power grid. One possible solution to the problem is to build gas turbines for the purpose of peak power generation capacity. An alternative option would be to increase customer flexibility; that is Demand Response. This master thesis investigates how the market for Demand Respond can be designed and which potential Demand Response volumes different policy programs might release. This is done through a mixed approach. Firstly, a scientific review of previously documented Demand Response experiences compares and categorizes different Demand Response programs in a typology based on the parameters cost, volume and feasibility. Subsequently an interview series with different market agents, predominantly through interviews with the Swedish energy intensive industry, identifies the existing Demand Response potential in Sweden and offers the paradigm needed to transfer the results to a future hypothetical situation. The typology of Demand Response programs and estimation of the future industrial Demand Response potential in Sweden are the main new knowledge contributions of this master thesis. The scope however is limited to the Swedish market geographically and focuses on the time horizon 2020-2050. It is also assumed that only existing technologies are likely to be implemented on a large scale over the given time horizon. The results of this master thesis suggest that a Real Time Pricing model would realize the largest potential of Demand Response and to a relatively low cost. This solution however requires actions and further development of both the pricing model and in technology. Firstly, all market agents must have free access to real time price information, something that is lacking today. Secondly, a smart grid with hourly meters is required. If policymakers consider security of supply to be more important than a low system cost, Direct Control or a continuation of the Strategic Reserve is to be preferred according to the conclusions of this report. Previous studies have placed the existing potential for industrial Demand Response in Sweden between 600 and 900 MW. This report suggests that the available volume is in the upper region of the mentioned interval already today and has potential to rise significantly in the future as industries become more aware of the concept and the transmission grid is becoming more flexible. Another driving force for increased Demand Response volumes are the increased price fluctuations which are expected as a consequence of a greater share of renewable energy sources. For the future Demand Response potential, a cost perspective is introduced and a distinction between different response durations is made. More specifically the results indicate that the potential industrial Demand Response volume will be about 1,500 MW in 2030, given a response duration time of 4 h and a spot price on 2,000 SEK/MWh. If 1,500 MW of peak generation capacity could be avoided through active Demand Side Management, it would reduce the system cost with about 350 Million SEK annually. Consequently, there is a business case for Demand Response and the issue is likely to be subject to further investigation and discussion in the future. On the long term however industrial Demand Response must be compared with other flexibility options, e.g. as import/export or energy storages but also residential Demand Response, and is in such case likely to be outcompeted due to its relatively high variable cost of providing capacity.

Mit dem zunehmenden Ausbau von fluktuierenden erneuerbaren Energien werden zusätzliche Technologien und/oder Bereitstellungskonzepte im Stromsystem benötigt, die den Ausgleich von Angebot und Nachfrage zu jeder Zeit gewährleisten. Neben Flexibilitätsoptionen wie Stromspeicher oder flexible konventionelle Kraftwerke, können Biogasanlagen eine Technologie zur Systemintegration von fluktuierenden erneuerbaren Energien darstellen. Der zukünftige kostenoptimale Einsatz von Biogasanlagen wurde bisher nicht ausreichend untersucht. Daher sollen die Forschungsfragen beantwortet werden, ob Biogasanlagen eine ökonomisch konkurrenzfähige Flexibilitätsoption darstellen und in welchem Umfang sowie mit welcher Betriebsweise diese zukünftig kostenoptimal eingesetzt werden sollten. Dazu wurden drei verschiedene Ausbaupfade mit sich unterscheidenden Kapazitäten für Biogasanlagen und weitere erneuerbare Energien zur Zielerreichung der nationalen ZubauZiele in Deutschland für den Zeitraum 2016 – 2035 definiert. Mit Hilfe der daraus abgeleiteten Residuallastdaten wurde der Einsatz der Biogasanlagen zur Systemstabilität optimiert. Die entstehenden Werte wurden im Anschluss verwendet, um mit einem nichtlinearen Optimierungsmodell den Einsatz von Flexibilitätsoptionen kostenminimal zu ermitteln. Der reduzierte Bedarf an Flexibilitätsoptionen durch zusätzliche (flexible) Biogasanlagen sowie die verringerte Stromeinspeisung aus anderen erneuerbaren Energien stellen dabei den Nutzen der Biogasanlagen dar. Zusätzliche Kosten entstehen durch die Flexibilisierung von Bestands- als auch durch den Bau und Betrieb von Neuanlagen. Kosten und Nutzen, die mit zusätzlichen Investitionen in flexible Biogasanlagen einhergehen, wurden abschließend in einer Kosten-Nutzen-Analyse gegenübergestellt. Ein erhöhter Anteil von Biogasanlagen im zukünftigen Stromsystem reduziert die Auslastung von vergleichsweise kostenintensiven Kraftwerken und verringert die Investitionen in Stromspeicher und konventionelle Kraftwerke. Dennoch wird durch die vergleichsweise hohen Kosten von (zusätzlichen) Biogasanlagen in keinem Szenario ein ökonomisch vorteilhaftes Ergebnis erzielt. Die Unwirtschaftlichkeit von Biogasanlagen könnte im Falle eines frühzeitigen Kohleausstiegs signifikant verringert werden. Grundsätzlich sollten Biogasanlagen möglichst flexibel eingesetzt werden, um fluktuierende erneuerbare Energien in das Stromsystem zu integrieren. Ein wirtschaftlicher Betrieb von Biogasanlagen im zukünftigen Stromsystem ist nur möglich, wenn deren Kosten gesenkt und/oder zusätzliche Nutzen in anderen Sektoren und Bereichen generiert werden. Bei einer geringen Zubau-Rate von Neuanlagen wären die geringsten Kostensenkungen notwendig. / To reduce the negative impact of climate change, the German government has decided to decrease greenhouse gas emissions in the energy sector through the extension of intermittent renewable energies, inter alia. The power supply from photovoltaic and wind power plants is characterized by intermittency that depends on local weather conditions. To ensure a sufficient power supply, further technologies and/or new concepts are required to balance demand and supply in the energy system with an increasing proportion of renewable energies. In addition storage technologies, the extension of power grids and conventional power plants, biogas plants can be one technological solution. However, the cost-efficient role of biogas plants has not been sufficiently assessed. The main objective of this thesis is to compare the economic feasibility of biogas plants with other flexibility options (namely storage technologies and conventional power plants) for the period of 2016 to 2035 in Germany´s electricity system. From an economic point of view, the cost-efficient future installed capacities and the modes of operation of biogas plants have to be analyzed. To do so, three biogas extension paths and renewable energy portfolios are defined for the considered period. Hourly residual load data are used to optimize the flexible power generation from biogas plants in all scenarios. The resulting residual load data (including biogas) is used as an input in a non-linear optimization model that simultaneously minimizes the costs of the hourly dispatch and the annual investments in conventional power plants and storage technologies. On the one hand, additional biogas plants in the future electricity system reduce the demand for additional flexibility options and substitute the generation from further renewable energies. On the other hand, the flexibilization of existing biogas plants and the investments in new biogas installations lead to additional costs. Finally, the resulting costs and benefits are quantified in a cost-benefit analysis. As a result, an increasing proportion of biogas plants reduces the demand for additional storage technologies and conventional power plants. Furthermore, the utilization of (existing) conventional power plants with high marginal costs in the considered period is decreased. However, in all scenarios, the costs of additional biogas plants exceed their benefits for the electricity system. This is why Germany´s electricity system is characterized by a sufficient installed capacity of existing flexibility options. An accelerated phasing-out of lignite- and coal-fired power plants to reach national greenhouse gas reduction target values improves the results of the cost-benefit analysis. The electricity generation from biogas plants should be as flexible as possible. The highest net present values are found in the extension path characterized by a low construction rate of new biogas plants. Nevertheless, compared to the phasing-out of biogas plants, additional biogas plants in Germany´s future electricity system require cost reductions and/or must be accompanied by further benefits in other sectors and areas to ensure economically feasible operation.

Urban drainage systems are influenced by several future drivers that affect the performance as well as the costs of the systems. The uncertainties associated with future drivers and their impact creates difficulties in designing urban drainage systems sustainably. A review of the different future drivers for urban drainage systems illustrates that no sufficient future predictions for the long operational life spans of the systems are possible. This dissertation contends that to deal with future uncertainties, flexibility in urban drainage systems is necessary. At present, profound insights about defining, measuring, and generating flexible urban drainage systems do not exist. This research systematically approaches these issues. First, a clear definition of flexibility and an approach for the measurement and optimization of flexibility is operationalized. Based on the generic definitions of flexibility used in other disciplines, a definition tailored for urban drainage systems is generated. As such, flexibility in sustainable urban drainage systems is defined as `the ability of urban drainage systems to use their active capacity to act and respond to relevant alterations during operation in a performance-efficient, timely, and cost-effective way'. Next, a method for measuring flexibility is provided based on the developed definition of flexibility including the metrics, 'range of change', 'life-cycle performance' and 'effort of change'. These metrics are integrated into a framework for the measurement of flexibility based on a comparison of performance and effort in different alternative solution with respect to different future states. In addition the metrics are the core components for optimizing flexible design of urban drainage system. The measurement method is successfully applied in two case studies in Tuttle Hill, UK and Hamburg-Wilhelmsburg, Germany. Using the developed definition and method for the measurement of flexibility, this dissertation illustrates that a transfer of the general theoretical background of flexibility to the field of urban drainage is possible. It is currently unclear how the flexible design of urban drainage systems can be executed. Based on a review, this research identifies nine potential principles of flexible design, described by the indicators of modularity, platform design, flexible elements, cost efficiency, decentralized design, real time control, low degree of specialization, scalability, and a combination of these principles. A case study of Hamburg-Boberg is then presented to analyze which of these principles of flexible design can be verified. For each alternative solution in the sample, the indicators for the different potential principles of flexible design as well as the flexibility provided by the design are calculated. Testing is done to determine if there is a significant correlation between the potential principles of flexible design and the measured flexibility using a chi-square-test and F-test. Two principles are verified with a high degree of confidence, 'platform design' and `flexible elements'. The `platform design' principle provides high flexibility, in which urban drainage system elements with high change costs are designed robustly with huge tolerance margins, whereas elements with low change costs are designed with flexibility options. The 'flexible elements' principle aims to include as many component elements as possible, which provides high individual flexibility in the design of the urban drainage system. These design principles and associated static indicators enable a quick screening of huge number alternative solutions and provide guidance for the development and optimization of flexible urban drainage system. Within the framework for optimization of flexibility, the design principles can help identify the most promising alternative solutions for the design of urban drainage systems. The optimization framework includes the following steps: identification of the required flexibility, generation of alternative solutions for the design of urban drainage systems, screening of the most promising alternative solutions, detailed measurement of flexibility provided by the alternative solutions; and selection of optimal solution. Hence out of a sample of different design approaches, the solutions with the highest flexibility could be identified. The successful application of flexible design in three case studies illustrates that the concept provides a suitable strategy for dealing with the challenges associated with future uncertainties. For urban drainage systems, flexible design guarantees high levels of performance in uncertain future states while reducing the effort required to adapt the system to changing future conditions. This study contends that flexibility allows for profound decision making for urban drainage design despite future uncertainties.

Durch den Ausbau an Wind- und PV-Anlagen in Deutschland wird der Flexibilitätsbedarf im Stromsystem steigen. Der Flexibilitätsbedarf kann zum einen durch verschiedene Technologien, z.B. Speicher oder Netze, und zum anderen durch die Stromnachfrage bereitgestellt werden. Eine gezielte Steuerung der Stromnachfrage wird als Demand Side Management (DSM) bezeichnet. Der zunehmend wetterabhängigen und fluktuierenden Stromerzeugung in Deutschland steht jedoch eine bis heute weitgehend unelastische Nachfrage gegenüber. In der Literatur sind verschiedene Arbeiten zu finden, die das Potential zur Lastabschaltung und verschiebung in Deutschland untersuchen. Hierbei liegt der Fokus auf absoluten Werten. Saisonale oder tageszeitliche Unterschiede bleiben dabei häufig unberücksichtigt. Die vorliegende Dissertation greift an dieser Stelle an und untersucht das Potential ausgewählter DSM-Anwendungen in stündlicher Auflösung. Die Ergebnisse zeigen, dass das verfügbare Potential starken saisonalen und tageszeitlichen Schwankungen unterliegt. Dementsprechend wird das DSM-Potential überschätzt, wenn nur absolute Werte betrachtet werden. Darüber hinaus zeigt die Autorin, welche Entwicklungen in den nächsten Jahren hinsichtlich der Verfügbarkeit des DSM-Potentials zu erwarten sind. Basierend auf der Potentialermittlung wird in der Dissertation die Rolle von DSM in einem EE-geprägten Stromsystem modellbasiert untersucht. Hierfür wird das lineare Optimierungsmodell ELTRAMOD, das den deutschen und europäischen Strommarkt abbildet, weiterentwickelt. Anhand verschiedener Szenarien wird zum einen der Beitrag von DSM zur Systemintegration von erneuerbaren Energien in Deutschland und zum anderen die Wechselwirkungen mit anderen Flexibilitätsoptionen (z.B. Speicher) untersucht. Die Ergebnisse zeigen, dass die DSM-Kategorien Lastabschaltung und verschiebung nur kurzzeitig auftretende Schwankungen der Einspeisung aus erneuerbaren Energien ausgleichen können. Zum Ausgleich großer Überschussmengen aus erneuerbaren Energien sind hingegen Power-to-X-Technologien, z.B. Power-to-Heat, besser geeignet.

Within the present work, the main objective is to identify interactions between flexibility demand and flexibility supply. Therefore, three research fields regarding the future transformation of the European energy system are addressed. First, an expansion of intermittent renewable energy sources (iRES) is discussed taking the potentials of wind and PV technologies into account. The analysis is based on fundamental considerations of generation characteristics as well as available potentials across 17 countries in central-western Europe. To emphasis the differences in electricity generation between wind and PV, an iRES expansion model is developed coping for geographically highly resolved weather data as well as for limitations of iRES potentials due to land-use restrictions and for energy-policy constraints. Three scenarios with varying Wind-PV ratio in total iRES electricity generation are evaluated. Second, the options to provide flexibility to balance the flexibility demand are introduced and mathematically implemented in ELTRAMOD. Therefore, the model was adjusted to represent multiple flexible technologies for upward, downward and shifting flexibility provision to cover the residual load. In a system perspective and a greenfield approach, the linear electricity market model enables the analysis of cost-optimal combinations of flexibility options against the background of scenarios with different flexibility demands. In addition, the third research field addresses the emerging developments of sector coupling by including selected Power-to-X technologies. A second scenario dimension analyses the role of energy storages in the energy end-use sectors for a more flexible sector coupling. The results underline the importance of the Wind-PV ratios in electricity generation when assessing flexibility demand and flexibility supply in model-based energy system analysis. Due to the higher seasonality of PV, the residual load parameter indicate higher iRES integration challenges in terms of flexible capacity requirements. Particularly the provision of spatial and temporal balancing flexibility is significantly influenced by a higher wind or a higher PV share in the iRES mix. With sector coupling, the value of temporal shifting is increasing. Hourly storages are not only highly sensitive to the Wind-PV ratio, but in addition strongly impacted by sector coupling. In both dimensions, a higher PV share is increasing the value for short-term shifting. Furthermore, sector coupling increases the need for additional electricity generation. Thereby, for peak-load capacity provision gas-fuelled power plant are optimal in the present work increasing the total emissions especially with higher PV shares. The sensitivity analysis shows the value of additional iRES capacities as well as of storage cost reductions to further reduce emissions.

Durch den Ausbau an Wind- und PV-Anlagen in Deutschland wird der Flexibilitätsbedarf im Stromsystem steigen. Der Flexibilitätsbedarf kann zum einen durch verschiedene Technologien, z.B. Speicher oder Netze, und zum anderen durch die Stromnachfrage bereitgestellt werden. Eine gezielte Steuerung der Stromnachfrage wird als Demand Side Management (DSM) bezeichnet. Der zunehmend wetterabhängigen und fluktuierenden Stromerzeugung in Deutschland steht jedoch eine bis heute weitgehend unelastische Nachfrage gegenüber. In der Literatur sind verschiedene Arbeiten zu finden, die das Potential zur Lastabschaltung und verschiebung in Deutschland untersuchen. Hierbei liegt der Fokus auf absoluten Werten. Saisonale oder tageszeitliche Unterschiede bleiben dabei häufig unberücksichtigt. Die vorliegende Dissertation greift an dieser Stelle an und untersucht das Potential ausgewählter DSM-Anwendungen in stündlicher Auflösung. Die Ergebnisse zeigen, dass das verfügbare Potential starken saisonalen und tageszeitlichen Schwankungen unterliegt. Dementsprechend wird das DSM-Potential überschätzt, wenn nur absolute Werte betrachtet werden. Darüber hinaus zeigt die Autorin, welche Entwicklungen in den nächsten Jahren hinsichtlich der Verfügbarkeit des DSM-Potentials zu erwarten sind. Basierend auf der Potentialermittlung wird in der Dissertation die Rolle von DSM in einem EE-geprägten Stromsystem modellbasiert untersucht. Hierfür wird das lineare Optimierungsmodell ELTRAMOD, das den deutschen und europäischen Strommarkt abbildet, weiterentwickelt. Anhand verschiedener Szenarien wird zum einen der Beitrag von DSM zur Systemintegration von erneuerbaren Energien in Deutschland und zum anderen die Wechselwirkungen mit anderen Flexibilitätsoptionen (z.B. Speicher) untersucht. Die Ergebnisse zeigen, dass die DSM-Kategorien Lastabschaltung und verschiebung nur kurzzeitig auftretende Schwankungen der Einspeisung aus erneuerbaren Energien ausgleichen können. Zum Ausgleich großer Überschussmengen aus erneuerbaren Energien sind hingegen Power-to-X-Technologien, z.B. Power-to-Heat, besser geeignet.