Fossil fuel will eventually become exhausted. Also, fossil fuels produce large amounts of carbon dioxide, which cannot only bring environment pollution, but can also cause global warming. Therefore, clean and renewable energy sources should be investigated. In this project, renewable wind power was considered. Wind energy is free, clean and available in large quantities, although it is difficult to use due to its stochastic variability. Energy storage can reduce this variability allowing energy production to match energy demand. In this study, different kinds of energy storage approaches were introduced, compared, and simulated by using half hourly wind data from the Met Office, UK, and half hourly load data from the University of Bath, UK. Hydrogen has higher mass energy density than all other energy storage methods. It is seen as a versatile energy carrier of the future, complementary to electricity and with the potential to replace fossil fuels due to its zero carbon emissions and abundance in nature. On the other hand, because hydrogen is the lightest element under normal conditions; the same amount of hydrogen must occupy a huge volume compared to other elements. The mature technology for converting hydrogen into electricity has high cost and low efficiency. These are big issues that limit the usage of hydrogen energy storage methods. Using wind and load data, a new algorithm was developed and used for sizing the wind turbine, and energy storage requirements. The traditional way to supply energy is distributing electricity, but in this PhD research, there are some discussions about a new method, hydrogen transport-hydrogen pipeline. From the results of the comparison and algorithm, a practical hydrogen energy storage system for the University of Bath network was proposed and designed. In the proposed design the energy from a wind turbine was directed to the load and the remaining excess power was used to produce hydrogen by water electrolysis. The hydrogen was stored in a high pressure compressed tank, and finally a hydrogen fuelled combined cycle gas turbine was used to convert the hydrogen to electricity. In this thesis, the dynamics of the complete hydrogen cycle energy storage and recovery mechanism are discussed, identifying potential applications such as power smoothing, peak lopping and extending power system controller ranges. The results of calculations of the payback time and revenue verify the feasibility of the designed hydrogen energy storage system. The main objective of the PhD was to design a practical hydrogen energy storage system for micro-grid applications. During this research, hydrogen energy storage was investigated to show that it does solve the problems arising from renewable energy.

With the increase in the world energy demand and environmental incentives, renewable energy sources (RES) need to determine their place as some of the primary power sources in future power systems. However, due to uncertain energy production, renewable energy sources cause unbalance in the power system due to the unsynchronized supply and electricity demand. The intermittent power production causes undesired power fluctuation, affecting the power quality and reliability of the power source. Energy storage is one solution that is debated to increase the reliability of renewable energy production. This thesis aims to model and simulate hybrid energy storage system (HESS), constructed of hydrogen and ultracapacitor energy storage, to investigate different operation strategies for everyday use and crises. The two different energy storage technologies complement each other, where hydrogen fuel cells can produce power for long periods of time while the ultracapacitor can quickly maintain the balance of production and consumption of electricity for a short instance. The HESS showed promising results for emergency power supply and supported service operation strategies. In case of a power shortage, the HESS could cover for the disconnected production. The ultracapacitor proved to be a suitable component due to its ability to support the shortcomings of a hydrogen energy storage system. Moreover, the HESS could meet the requirements to deliver support services. However, further studies have to be done to investigate how the HESS can deliver multiple support services to increase profit and help maintain the power system's balance and security.

Next generation telecommunication satellites will demand an increasing amount of power in the range of 30 kW or more within the next 10 years. Battery technology that can sustain 30 kW for an eclipse length of up to 72 minutes will represent a major impact on the total mass of the satellite, even with new Li-ion battery technologies. Regenerative fuel cell systems (RFCS) were identified years ago as a possible alternative to rechargeable batteries. Nevertheless, one major drawback was identified by several independent system studies, namely the need to dissipate large amounts of heat from the fuel cell (FC) during eclipse. This in turn requires massive thermal hardware (mainly large radiators) that can contribute up to 50% of the system mass. In order to overcome this issue, the use of metal hydrides (MH) as combined hydrogen and heat storage system was suggested as a starting point of the research presented in this thesis. During eclipse the FC must dissipate waste heat, and at the same time the MH tank must absorb heat in order to desorb hydrogen. Rather than dissipating the waste heat from the FC directly through a radiator, it can be stored solely, or partly, in the MH tank, to be dissipated during Equinox, with a 20 times slower rate, requiring a radiator with significantly less volume and mass. This thesis aims to present the potential of using such MH storage tanks to alternately store hydrogen and waste heat from the FC on-board a spacecraft, investigated by theoretical and experimental means. The model application for the MH tank technology considered in this thesis is a 39 kW telecommunication satellite. Nevertheless, the derived results are to be considered a generic outcome and can be translated or scaled to many other applications. / Es kann davon ausgegangen werden, dass der Trend hin zu Telekommunikationssatelliten mit immer höherer Leistung in den nächsten 10 Jahren zu Satelliten-Plattformen mit 30kW und mehr führen wird. Batterien, welche eine Leistung von 30kW für Eklipse-Längen von 72 Minuten zur Verfügung stellen müssen, werden daher einen immer größeren Einfluss auf die Gesamtmasse des Satelliten haben. Regenerative Brennstoffzellensysteme wurden daher schon vor Jahren als mögliche Alternative zu wieder aufladbaren Batterien untersucht. Mehrere unabhängige Studien sind zu dem Schluss gekommen, dass die größte Problematik in der Einführung von Brennstoffzellensystemen auf Satelliten darin besteht, die relativ großen Mengen an Abwärme effizient abzustrahlen. Die Radiatoren, die hierfür benötigt werden können 50% der Masse des Gesamtsystems ausmachen. Um dieses Problem zu überwinden wurde als Startpunkt der vorliegenden Arbeit die Nutzung von Metallhydriden als kombinierter Wasserstoff- und Wärmespeicher vorgeschlagen. Während sich der Satellit im Erdschatten befindet produziert die Brennstoffzelle Abwärme, während zur gleichen Zeit der Metallhydrid-Tank Wärme benötigt um Wasserstoff freizusetzen. Die Abwärme der Brennstoffzelle muss daher nicht direkt über Radiatoren abgestrahlt werden, sondern wird von Metallhydrid-Tank absorbiert um dann während dem restlichen Erdumlauf 20 mal langsamer mit einem deutlich kleinerem und leichteren Radiator abgegeben werden zu können. Diese Arbeit hat zum Ziel, das durch analytische und experimentelle Methoden untersuchte Potential der Anwendung einer solchen Technologie auf Satelliten zu präsentieren. Die Modellapplikation für diese Arbeit ist ein 39kW Telekommunikationssatellit. Die Ergebnisse lassen sich allerdings auch auf andere Anwendungen skalieren und übertragen.

Next generation telecommunication satellites will demand an increasing amount of power in the range of 30 kW or more within the next 10 years. Battery technology that can sustain 30 kW for an eclipse length of up to 72 minutes will represent a major impact on the total mass of the satellite, even with new Li-ion battery technologies. Regenerative fuel cell systems (RFCS) were identified years ago as a possible alternative to rechargeable batteries. Nevertheless, one major drawback was identified by several independent system studies, namely the need to dissipate large amounts of heat from the fuel cell (FC) during eclipse. This in turn requires massive thermal hardware (mainly large radiators) that can contribute up to 50% of the system mass. In order to overcome this issue, the use of metal hydrides (MH) as combined hydrogen and heat storage system was suggested as a starting point of the research presented in this thesis. During eclipse the FC must dissipate waste heat, and at the same time the MH tank must absorb heat in order to desorb hydrogen. Rather than dissipating the waste heat from the FC directly through a radiator, it can be stored solely, or partly, in the MH tank, to be dissipated during Equinox, with a 20 times slower rate, requiring a radiator with significantly less volume and mass. This thesis aims to present the potential of using such MH storage tanks to alternately store hydrogen and waste heat from the FC on-board a spacecraft, investigated by theoretical and experimental means. The model application for the MH tank technology considered in this thesis is a 39 kW telecommunication satellite. Nevertheless, the derived results are to be considered a generic outcome and can be translated or scaled to many other applications.:1 Introduction 2 The Metal Hydride Regenerative Fuel Cell System (MH-RFCS) 3 Metal Hydride Material Selection and Characterization 4 Design and Optimization of the Metal Hydride Tank System 5 Design and Manufacturing of a Technology Demonstrator 6 Simulation of the Metal Hydride Tank Performance 7 Experimental Results and Discussion 8 Outlook 9 Bibliography / Es kann davon ausgegangen werden, dass der Trend hin zu Telekommunikationssatelliten mit immer höherer Leistung in den nächsten 10 Jahren zu Satelliten-Plattformen mit 30kW und mehr führen wird. Batterien, welche eine Leistung von 30kW für Eklipse-Längen von 72 Minuten zur Verfügung stellen müssen, werden daher einen immer größeren Einfluss auf die Gesamtmasse des Satelliten haben. Regenerative Brennstoffzellensysteme wurden daher schon vor Jahren als mögliche Alternative zu wieder aufladbaren Batterien untersucht. Mehrere unabhängige Studien sind zu dem Schluss gekommen, dass die größte Problematik in der Einführung von Brennstoffzellensystemen auf Satelliten darin besteht, die relativ großen Mengen an Abwärme effizient abzustrahlen. Die Radiatoren, die hierfür benötigt werden können 50% der Masse des Gesamtsystems ausmachen. Um dieses Problem zu überwinden wurde als Startpunkt der vorliegenden Arbeit die Nutzung von Metallhydriden als kombinierter Wasserstoff- und Wärmespeicher vorgeschlagen. Während sich der Satellit im Erdschatten befindet produziert die Brennstoffzelle Abwärme, während zur gleichen Zeit der Metallhydrid-Tank Wärme benötigt um Wasserstoff freizusetzen. Die Abwärme der Brennstoffzelle muss daher nicht direkt über Radiatoren abgestrahlt werden, sondern wird von Metallhydrid-Tank absorbiert um dann während dem restlichen Erdumlauf 20 mal langsamer mit einem deutlich kleinerem und leichteren Radiator abgegeben werden zu können. Diese Arbeit hat zum Ziel, das durch analytische und experimentelle Methoden untersuchte Potential der Anwendung einer solchen Technologie auf Satelliten zu präsentieren. Die Modellapplikation für diese Arbeit ist ein 39kW Telekommunikationssatellit. Die Ergebnisse lassen sich allerdings auch auf andere Anwendungen skalieren und übertragen.:1 Introduction 2 The Metal Hydride Regenerative Fuel Cell System (MH-RFCS) 3 Metal Hydride Material Selection and Characterization 4 Design and Optimization of the Metal Hydride Tank System 5 Design and Manufacturing of a Technology Demonstrator 6 Simulation of the Metal Hydride Tank Performance 7 Experimental Results and Discussion 8 Outlook 9 Bibliography

This thesis explores what Karlstad Airport needs to go 100% green. Photovoltaics are assumed to be installed at the facility and a Hydrogen Energy Storage System and Battery Energy Storage System will be evaluated to reduce peaks during charging of the planes. Different power peak limits are explored as well as different sized Energy Storage Systems and later evaluated economically. A method to find the cheapest possible system is created with some assumptions and is then used to evaluate throughout the whole dataset. In the end any of the different sized Energy Storage Systems reduces the profitability when considering each systems expected lifecycle.