Results have shown that flow batteries may be a solution in the future as an effective and environmental friendly method to an energy storage system (ESS). The technology is reliable and has a high efficiency that comes with low energy losses and a long lifetime. The range of possible fields is suitable for cutting energy peaks in the power grid, by always have a ready and available energy storage that balances the production. By comparing the advantages of flow batteries with conventional batteries it is mainly the fact that they can conserve energy for a long time without being self-discharged thanks to that the storage capacity is in principle endless and limited by the size of the electrolytes tanks that makes them a great energy storage system. The batteries won’t take any damage or decrease in performance when charging or discharging it or if you exhausts it to 100 % and leave it discharged for a long time. The only disadvantages with flow batteries are that they are built upon an advanced design and are built of components made of expensive materials. The main objective of this thesis is to develop an experimental basis for assessing a small pilot module of a flow battery with respect to how different concentrations of salts, flow rates and different currents/voltages affect the performance of the battery. We start by performing the experiment with a polymeric ion exchange membrane and see what values and the advantages and disadvantages it entails.

Energy storage devices are generally evaluated on two main requirements; power and energy. In supercapacitors these two performance criteria are altered by the capacitance, resistance and voltage. (For complete abstract open document)

Recently, decentralized household photovoltaic (PV) systems have become more affordable and there is a tendency to decrease subsidies for the PV excess electricity fed into the grid. Therefore, there is growing interest in methods to increase the self-consumption (SC), which is the part of the electricity produced by PV and directly consumed on buildings. It has been found that battery storage is an effective way to achieve this. When there is a heat pump system installed, thermal energy storage using the thermal mass of the building or hot water tanks, can also be used to increase the household self-sufficiency and minimize the final energy use. The main aim of this thesis is to develop operational control strategies for the heating system of a single-family house with an exhaust air heat pump, a photovoltaic system and energy storage. In order to accomplish this a detailed system model was developed in TRNSYS 17, which includes a six-zone building model and the heat pump control. Moreover, these control strategies include short-term weather and price forecast services.  Another objective is to evaluate the impact on the benefit of these control strategies in terms of energy use and economic performance for a wide range of boundary conditions (country/climate, electricity prices, occupancy and appliance loads).  Results show that the control using a forecast of dynamic electricity price in most locations leads to greater final energy savings than those due to the control using thermal storage for excess PV production. The exception is Sweden, where the result is the opposite. Moreover, the addition of battery storage leads to greater decreases in final energy than the use of the thermal storage (TH mode), which is limited to the thermal mass of the building and small hot water tank of the compact heat pump. As far as the impact of the advanced control (combined use of TH and PRICE) on cost savings is concerned, savings (up to 175 €) are possible in Spain and in Germany. The design of the TH and PRICE mode show low computational complexity that can be easily implemented in existing heat pump controllers. Additionally, the PRICE mode should have no capital and running cost for the end user while the TH mode might require an external electricity meter. Another yet implication with the TH mode is the need to activate the room thermostatic valve.

The global push for increased renewable energy in power production is reshaping how industries approach energy systems. As the urgency to combat climate change grows, industries are integrating alternative power pathways alongside existing systems. This shift is driven by factors such as renewable energy adoption, energy storage advances, decentralization, electrification, circular economy principles, regulatory support, sustainability goals, and technological progress. These changes not only yield economic benefits but also enhance environmental and social impact. Integrating alternative pathways necessitates strategic planning, optimization, and a phased approach for seamless integration. Through these transformations, industries position themselves as sustainability leaders, align with climate goals, and ensure long-term energy security. The proposed implementation of a photovoltaic (PV) system at SSAB's steel production plant in Borlänge, specifically for forming line 4's electricity needs, will have a positive impact. This integration introduces renewable energy generation, offsetting the load and reducing reliance on the grid during peak hours, potentially leading to lower costs. It aligns with SSAB's environmental goals by curbing emissions, bolsters energy resilience, and aiding peak demand management. However, challenges in grid integration and infrastructure adjustments must be addressed for successful implementation. Overall, this move embodies SSAB's commitment to sustainability and efficient operations.  Through the utilization of simulation tools such as PVsyst and Homer Pro, an extensive study was conducted to investigate diverse scenarios involving combinations of a PV system, hydrogen modules, batteries, and a grid-connected load. The primary aim was to assess the feasibility of these scenarios within the energy system context. By leveraging PVsyst's capabilities for photovoltaic system analysis and Homer Pro's system optimization features, the study comprehensively examines interactions between electricity generation, storage, and consumption. This simulation-driven approach provided valuable insights into the performance dynamics, energy balance, and economic viability of each configuration, aiding in the informed selection of optimal combinations that align with the project's feasibility objectives. The results obtained suggest that the ideal size for the PV system in this context is 2.7 MW, allowing for an annual energy generation of 2.5 GWh. The electricity output aligns well with the yearly demand of 2.4 GWh for Forming Line 4 The results from different scenarios offer valuable insights into how integrating renewable energy and incorporating energy storage affect the overall efficiency and cost-effectiveness of the system. Each scenario was assessed in comparison to the base case of grid connection, uncovering a spectrum of LCOE values. It is noteworthy that the highest LCOE, reaching 0.12 €/kWh, was observed when all renewable resources were combined, whereas the lowest LCOE, at 0.059 €/kWh, was achieved with the PV system-only configuration.

No description available.

La montée en puissance des systèmes de production de l'énergie électrique, à partir de centrales éoliennes ou photovoltaïques, a fait apparaître un besoin aigu en moyens de stockage de cette énergie. Les technologies d'accumulateurs électrochimiques sont à même de répondre à cette problématique, en particulier les batteries sodium chlorure de nickel, une technologie d'accumulateur à haute température. Mais afin de gérer au mieux les performances de ces batteries, il est nécessaire d'avoir une connaissance approfondie du comportement électrothermique des cellules unitaires les composant. Ce travail de thèse présente en détail le développement d'un modèle multiphysique 2D d'une cellule Na-MCl2 commerciale, à même de simuler son fonctionnement en décharge à courant constant. Ce modèle a été construit sur une étude approfondie des mécanismes électrochimiques à l'œuvre dans ce type de technologie, et des effets thermiques associés. Il repose également sur la synthèse et la critique des modèles proposés précédemment dans la littérature. Le modèle inédit proposé dans ce manuscrit permet de prendre en compte deux réactions électrochimiques simultanées, ainsi que le comportement thermique de la cellule. Le modèle a été validé en confrontant les résultats de simulations aux performances électriques réelles d'une cellule commerciale Na-MCl2 (incluant une caractérisation des phénomènes électrochimiques par voltammetrie cyclique). Ce modèle permet de simuler avec succès des décharges à courant constant à différents régimes, et à partir de différentes températures. Il est également capable de prévoir les effets électrothermiques qui seraient consécutifs à un changement de design de la cellule (design structurel et de constitution). / The growing production capacity of wind turbines or photo-voltaic plants has revealed an acute need for electric energy storage systems. Electrochemical accumulator technologies are able to address this issue, in particular sodium nickel chloride batteries, a high temperature battery system. But to enhance the energy management of these batteries, it is necessary to have a deep knowledge of the electro-thermal behavior of its unit cell component. This thesis presents the development of a comprehensive multiphysics 2D model of a commercial Na-MCl2 cell, able to simulate its operation in constant current discharge. This model was built on a thorough study of electrochemical mechanisms at work with this type of technology, and its associated thermal effects. It is also based on the synthesis of existing models, and their critique. The new model proposed in this manuscript can take into account two simultaneous electrochemical reactions, as well as the thermal behavior of the cell. The model was validated by comparison between simulation results and the actual electrical performances of a commercial Na-MCl2 cell (including the characterization of electrochemical phenomena by cyclic voltammetry). This model successfully simulates constant current discharges at different rates, and from different temperatures. It is also capable of predicting the electro-thermal effects consecutive to design changes of the cell (structural and relevant to the active material).