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The challenge of managing the present and projected electricity energy needs along with targets of mitigating CO2 emissions leads to the need for energy systems to reduce reliance on fossil fuels and rely on more energy from renewable sources. The integration of more renewable energy technologies to meet present and future electricity demand leads to more challenges in matching the trade-o between economic, resilient, reliable and environmentally friendly solutions. Energy storage technologies can provide temporal resilience to energy systems by solving these challenges. Energy storage systems can improve the reliability of energy systems by reducing the mismatch between supply and demand due to the intermittency of renewable energy sources. This thesis presents a comprehensive analysis of various energy storage systems, analyzing their speci c characteristics including capital cost, e ciency, lifetime and their usefulness in di erent applications. Di erent hybrid energy systems are designed to analyze the impacts of renewable and non-renewable energy sources and energy storage systems in residential on-grid and o -grid buildings and districts. An optimization analysis is performed to determine which technology combinations provide the most economic solution to meet electric energy demands. The optimization analysis is solved using the "energy hub" model formulation which optimizes energy system operation and capacity of di erent technologies. Di erent energy systems can be optimized by using energy hub model, including multiple input energy carriers that are converted to multiple energy outputs. The analysis in this thesis employs a building simulation tool to model residential building, and real data sets to explore the di erent electricity pro le e ects on the results. The environmental e ect of hybrid energy systems comparing with base cases of conventional energy systems or grid connection are also analyzed. Results show that the feasibility of energy storage systems is a factor of di erent variables including capital cost of energy converters and energy storage systems, cost of input streams (grid electricity in on-grid systems and diesel fuel in o -grid systems, energy demand pro les and availability of renewable energy sources. The on-grid single and district buildings do not select storage technologies at current costs due to cheap grid electricity. Reduction in the cost of renewable energy technologies and/or energy storage systems (e.g. Li-ion batteries) results in more energy storage installations. In o -grid systems (single buildings and districts), Li-ion battery and pumped hydro are the main storage systems that can balance the daily and seasonal energy demands. / Graduate / 2021-03-13

The environmental awareness has led to many political decisions and initiated laws that regulate the market towards responsible energy usage. The demand of sustainable power has led to an increasing integration of renewable energy sources to the electric grid. Solar power is the 3rd largest renewable power source after wind and bio-power. One of the main reasons to this fast expansion is the German renewable energy act that has motivated households to install PV systems in their houses. This has led to a large amount of producers on the low-voltage network. The small scale producers receive compensation for electricity generated from the PV systems, both when it is used directly in the producer’s home and when it is sold to the grid due to low usage. The systems can be more profitable by storing the energy instead of selling it on the grid. In this way the amount of bought electricity can be reduced. There are concerns regarding the connection of renewable sources to the grid. This project aims to examine the impact from single-phase PV systems on the low-voltage grid. The focus of this bachelor thesis is understanding problems such as harmonic distortion and grid asymmetry. Simulations have been carried out using the software MATLAB in order to study harmonic distortion in the output of a single-phase PV system. Grid asymmetry is examined through calculations and simulations of a worst case scenario in the software NEPLAN. This scenario contains a low voltage grid with a star-star connected transformer, where all PV-systems are connected to the same phase. The simulations in combination with a literature review have provided the conclusion that harmonic distortion caused by the inverter becomes higher when the voltage supply is too low. Integration of battery energy storage systems together with PV systems does not cause additional harmonic distortion. The results also show how single-phase systems contribute to the asymmetry in the grid. When the production from the PV systems is high, and all systems are connected to a certain phase, the current and voltage will also have an impact on the other phases in the worst case scenario.

Doctor Scientiae / Ti – based AB and AB₂ hydride forming materials have shown to be very promising hydrogen storage alloys due to their reasonable reversible hydrogen storage capacity at near ambient conditions, abundance and low cost. However, these materials are not used extensively due to their poor activation performances and poisoning tolerance, resulting insignificant impeding of hydrogen sorption. The overall goal of this project was to develop the knowledge base for solid-state hydrogen storage technology suitable for stationary and special vehicular applications focussing mainly on Ti – based metal hydrides. In order to accomplish this goal, the project had a dual focus which included the synthesis methodology of Ti – based AB and AB₂ materials and the development of new surface engineering solutions, based on electroless plating and chemical vapour deposition on the surface modification of Ti – based metal hydride forming materials using Pd-based catalytic layers. TiFe alloy was synthesised by sintering of the Ti and Fe powders and by arc-melting. Sintered samples revealed three phases: TiFe (major), Ti₄Fe₂O, and β-Ti. Hydrogen absorption showed that the sintered material was almost fully activated after the first vacuum heating (400 °C) when compared to the arc-melted sample requiring several activation cycles. The increase in the hydrogen absorption kinetics of the sintered sample was associated with the influence of the formed hydrogen transfer catalyst, viz. oxygen containing Ti₄Fe₂O₁₋ₓ and β-Ti, which was confirmed by the XRD data from the samples before and after hydrogenation. The introduction of oxygen impurity into TiFe alloy observed in the sintered sample significantly influenced on its PCT performances, due to formation of stable hydrides of the impurity phases, as well as destabilisation of both β-TiFeH and, especially, γ-TiFeH₂. This finally resulted in the decrease of the reversible hydrogen storage capacity of the oxygen-contaminated sample. TiFe alloy was also prepared via induction melting using graphite and alumo-silica crucibles. It was shown that the samples prepared via the graphite crucible produced TiFe alloy as the major phase, whereas the alumo-silica crucible produced Ti₄Fe₂O₁-x and TiFe₂ as the major phases, and TiFe alloy as the minor one. A new method for the production of TiFe – based materials by two-stage reduction of ilmenite (FeTiO₃) using H₂ and CaH₂ as reducing agents was developed. The reversible hydrogen absorption performance of the TiFe – based material prepared via reduction of ilmenite was 0.5 wt. % H, although hydrogen absorption capacity of TiFe reported in the literature should be about 1.8 wt. %. The main reason for this low hydrogen capacity is due to large amount of oxygen present in the as prepared TiFe alloy. Thus to improve the hydrogen absorption of the raw TiFe alloy, it was melted with Zr, Cr, Mn, Ni and Cu to yield an AB₂ alloy. For the as prepared AB₂ alloy, the reversible hydrogen sorption capacity was about 1.3 wt. % H at P=40 bar and >1.8 wt.% at P=150 bar, which is acceptable for stationary applications. Finally, the material was found to be superior as compared to known AB₂-type alloys, as regards to its poisoning tolerance: 10-minutes long exposure of the dehydrogenated material to air results in a slight decrease of the hydrogen absorption capacity, but almost does not reduce the rate of the hydrogenation. Hydrogen storage performance of the TiFe-based materials suffers from difficulties with hydrogenation and sensitivity towards impurities in hydrogen gas, reducing hydrogen uptake rates and decreasing the cycle stability. An efficient solution to this problem is in modification of the material surface by the deposition of metals (including Palladium) capable of catalysing the dissociative chemisorption of hydrogen molecules. In this work, the surface modification of TiFe alloy was performed using autocatalytic deposition using PdCl₂ as the Pd precursor and metal-organic chemical vapour deposition technique (MO CVD), by thermal decomposition of palladium (II) acetylacetonate (Pd[acac]₂) mixed with the powder of the parent alloy. After surface modification of TiFe – based metal hydride materials with Pd, the alloy activation performance improved resulting in the alloy absorbing hydrogen without any activation process. The material also showed to absorb hydrogen after exposure to air, which otherwise proved detrimental.

The master thesis deals with the logistic concept of the storage process in a selected business enterprise, which deals with the commercial activity in the field of spare parts and accessories for the automotive industry. More specifically, its main stock. Based on the theoretical part, where the basic concepts and methods concerning the logistic processes in the company are explained, the analytical part is elaborated. From this part proposals are made for the optimization of the storage processes from the technological and organizational standpoint.

The Masters thesis deals with the analysis in a selected company, which is focused on trade, transport, warehousing and logistics services. Based on the theoretical part, which explains the concepts from logistics to warehousing, the analytical part is prepared for the current state of operational warehousing processes of the company. The last proposal part also describes the proposals for a new commercial and warehouse operation, for which the company has decided.

The subject of the diploma thesis is storage and current storage technology in a business company. The first part of the thesis defines the theoretical basis of logistics, supply, international trade and especially warehousing. The practical part is focused on the current situation in the company and inventory analysis. Based on the analysis and all the findings, two proposals were submitted that could contribute to the company to improve the current storage and storage technology and thus increase customer satisfaction.

The diplom thesis is focused on storage process of component in production company, which is engaged on production of products for automotive and railway industry. There is made analysis of current status of storage process in thesis. And also based on theoretical knowledges there are proposed solution that help to remove identified weaknesses.

The aim of this thesis is to objectify the discussion regarding the availability of technologies related to the German energy transition. This work describes the state of development of relevant technologies on the basis of Technology Readiness Levels. Further, it points out development potentials and limits as well as the necessary power capacities needed for a certain energy system design that is mainly based on electricity. Thus, the scope is set to renewable energy sources suited to provide electricity in Germany, technologies that convert primary electricity for other energy sectors (heating and mobility) and storage technologies. Additionally, non-conventional technologies for electricity supply and grid technologies are examined. The underlying Technology Readiness Assessment is a method used to determine the maturity of these systems or their essential components. The major criteria for assessment are scale, system fidelity and environment. In order to estimate the relevant magnitudes for certain energy technologies regarding power and storage capacities, a comprehensible simulation model is drafted and implemented. It allows the calculation of a renewable, volatile power supply based on historic data and the display of load and storage characteristics. As a result, the Technology Readiness Level of the different systems examined varies widely. For every step in the direct or indirect usage of renewable intermittent energy sources technologies on megawatt scale are commercially available. The necessary scale for the energy storage capacity is in terawatt hours. Based on the examined storage technologies, only chemical storages potentially provide this magnitude. Further, the required total power capacities for complementary conversion technologies lay in the two-digit gigawatt range.:Abstract 2 Contents 3 1. Introduction 7 2. General remarks on the current state of the German energy system 12 3. Method of Technology Readiness Assessment 16 3.1. Fundamentals of the method 16 3.2. Drawbacks of TRA 19 3.3. Extended Readiness Levels 20 3.4. Conducting the Technology Readiness Assessment 21 3.5. Expert interviews 23 3.6. References 24 4. Preliminary remarks on the TRL assessment 25 4.1. Mission and environment 25 4.2. Simplifications and neglected aspects 26 4.3. References 26 5. Wind power 27 5.1. Technology description 27 5.2. Estimation of potential 32 5.3. Representation of the achieved state of expansion 37 5.4. TRL assessment 39 5.5. References 40 6. Solar energy 44 6.1. Technology description 44 6.2. Solar thermal energy 44 6.3. Photovoltaic technologies 45 6.4. Estimation of potential 48 6.5. Representation of the achieved state of expansion 52 6.6. TRL assessment 53 6.7. References 54 7. Geothermal energy 56 7.1. Technology description 56 7.2. Estimation of potential 59 7.3. Description of the current level of expansion 62 7.4. TRL assessment 63 7.5. References 64 8. Hydropower 66 8.1. Technology description 66 8.2. Estimation of potential 68 8.3. Description of the current level of development 70 8.4. TRL assessment 71 8.5. References 72 9. Biomass 73 9.1. Technology description 73 9.2. Estimation of potential 75 9.3. Representation of the achieved state of expansion 79 9.4. TRL assessment 81 9.5. References 82 10. Transmission and distribution grids 84 10.1. Technology description 84 10.2. Estimation of potential 90 10.3. Representation of the achieved state of expansion 94 10.4. TRL assessment 95 10.5. References 96 11. Power-to-heat 100 11.1. Technology description 100 11.2. Estimation of potential 104 11.3. Representation of the achieved state of expansion 107 11.4. TRL assessment 108 11.5. References 109 12. Power-to-cold 111 12.1. Technology description 111 12.2. Estimation of potential 114 12.3. Representation of the achieved state of expansion 117 12.4. TRL assessment 118 12.5. References 120 13. Power-to-chemicals 122 13.1. Technology description 122 13.2. Estimation of potential 134 13.3. Representation of the achieved state of expansion 137 13.4. TRL assessment 138 13.5. Manufacturer overview for electrolysis systems 140 13.6. References 142 14. Mechanical storage 146 14.1. Technology description 146 14.2. Estimation of potential 148 14.3. Representation of the achieved state of expansion 155 14.4. TRL assessment 155 14.5. References 158 15. Thermal storage 160 15.1. Technology description 160 15.2. Estimation of potential 164 15.3. Representation of the achieved state of expansion 169 15.4. TRL assessment 170 15.5. References 172 16. Chemical storage systems 175 16.1. Technology description 175 16.2. Estimation of potential 180 16.3. Representation of the achieved state of expansion 185 16.4. TRL assessment 186 16.5. References 188 17. Electro-chemical storage systems 191 17.1. Technology description 191 17.2. Estimation of potential 198 17.3. Representation of the achieved state of expansion 202 17.4. TRL assessment 202 17.5. References 204 18. Gas engines/gas turbines for hydrogen combustion 207 18.1. Technology description 207 18.2. Estimation of potential 208 18.3. Representation of the achieved state of expansion 211 18.4. TRL assessment 211 18.5. References 213 19. Chemicals-to-Power – Fuel cells 214 19.1. Technology description 214 19.2. Estimation of potential 218 19.3. Representation of the achieved state of expansion 221 19.4. TRL assessment 223 19.5. References 225 20. Interim conclusion for TRA 227 21. Evaluation of system integration 230 21.1. Modelling approach 230 21.2. Scenarios for a renewable energy supply 238 21.3. Results of the simulation 238 21.4. Consequences 244 21.5. References 245 22. Summary and Outlook 247 23. Abbreviations and symbols 249 24. Indices 254 25. List of Figures 255 26. List of Tables 258 27. Appendix 260 27.1. DOE TRL definition and description 260 27.2. Visualized summary of TRLs 262