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<p>The lucrative characteristics of high energy and power density from lithium-ion batteries have also become drawbacks when they are not handled appropriately. The reactive and flammable materials present within the cell raise safety concerns which need to be addressed. Aging of the cell components occurs in a natural way due to continuous cycling. Constant intercalation/deintercalation of Li-ions into the active materials induces stresses that in the long-term cycling mechanically modify the electrodes in an irreversible way. Also, electrode/electrolyte side reactions diminish the Li-ion inventory reducing the cell capacity and lifetime. Along with cell aging, intentional/unintentional abuse tests can occur at the hands of the final user. Improper handling and operation may lead the Li-ion cell to failure and possibly going into thermal runaway. This condition represents a threat to safety not only for cell integrity but also for user safety. Failure event can occur not only in brand new cells but also in aged cells. Current degradation studies focus either on the long-term aging degradation mechanisms or on fresh new cells’ abuse test. And few of them focused on the combination of both of them. </p>In this work, the degradation of Li-ion cells is investigated at different levels. First, at the electrode level, the effect of electrode processing and the intercalation properties of an anode and cathode materials is investigated. Then, at the cell level, abuse conditions such as external short, overcharge and overdischarge are studied in fresh and aged cells with different levels of degradation. Last but not least, the cells are assembled in a module configuration to investigate how a minor difference from one cell to another can affect the long-term performance. The aim is accomplished via a controlled lab test approach in order to get insights about the electrochemical, thermal and morphological changes that take place when the cell degrades.<br>

This study deals with solidification and melting of some typical encapsulated ice thermal energy storage geometries. Using ANSYS GAMBIT and FLUENT 6.0 software, HTF fluid motion past encapsulated water (ice) geometries, varying HTF flow rates and inlet temperatures are analyzed. The main source of irreversibility was from entropy generation accompanying phase change, although viscous dissipation losses were included. Energy efficiencies were well over 99% for all cases, while exergy efficiencies ranged from 70% to 92%. By far, the most influential variable was the inlet HTF temperature; higher efficiencies resulted from inlet HTF temperatures closer to the solidification temperature of water. / UOIT

Global environmental concerns associated with conventional energy generation have led to the rapid growth of wind energy applications in electric power systems. Growing demand for electrical energy and concerns associated with limited reserves of fossil fuels are also responsible for the development and increase in wind energy utilization. Many jurisdictions around the world have set high wind penetration targets in their energy generation mix.<p> The contribution of wind farms to the overall system reliability is limited by the uncertainty in power output from the highly variable energy source. High wind penetration can lead to high risk levels in power system reliability and stability. In order to maintain the system stability, wind energy dispatch is usually restricted and energy storage is considered to smooth out the fluctuations and improve supply continuity. The research work presented in this thesis is focused on developing reliability models for evaluating the benefits associated with wind power and energy storage in electric power generating systems. An interactive method using a sequential Monte Carlo simulation technique that incorporates wind farm and energy storage operating strategies is developed and employed in this research. Different operating strategies are compared and the resulting benefits are evaluated. Important system impacts on the reliability benefits from wind power and energy storage are illustrated. Hydro facilities with energy storage capability can alleviate the impact of wind power fluctuations and also contribute to system adequacy. A simulation technique for an energy limited hydro plant and wind farm coordination is developed considering the chronological variation in the wind, water and the energy demand. The IEEE four-state model is incorporated in the developed technique to recognize the intermittent operation of hydro units. Quantitative assessment of reliability benefits from effective utilization of wind and water resources are conducted through a range of sensitivity studies. The information provided and the examples illustrated in this thesis should prove useful to power system planners and wind developers to assess the reliability benefit from utilizing wind energy and energy storage and the coordination between wind and hydro power in electric power systems.

This project served to analyze the effects that energy storage can have on energy production.  The study was aimed at Johannes CHP bio fuel. Johannes produces electricity for the SE3 region and heat for the district heating in Gävle. The electricity market is the main driving factor for energy production. It is ideal for Johannes to produce as much electricity as possible during high Elspot prices. Two accumulator tanks are already installed at Johannes so the surplus of heat can be stored from high electrical production. This study served to utilize the planning horizons for the future Elspot prices. The two forecasting methods presented are the 12 hour prices presented by Nord pool and the four day forecast predicted by ARIMA modeling. Several different energy storage technologies were theoretically discussed after which Gravity Potential Module, latent heat storage using phase change materials and open accumulator tanks were analyzed. The ideal system proved to be utilizing the four day ARIMA modeled forecast with a storage system consisting of Gravity Potential Module and latent heat storage. The system resulted in a gross profit of 1.4 million SEK and an increased average electrical production efficiency of .02% during 2011.

With power system restructuring, continuous growth of demand, and deregulation, small, scattered generators referred to as Distributed Generation (DG) are predicted to play a key role in the power distribution system. Moreover, among the different types of DG units, it is widely accepted that renewable DG units are the key to a sustainable energy supply infrastructure, since they are both inexhaustible and non-polluting. However the intermittent nature and the uncertainties associated with the renewable resources create special technical and economical challenges that have to be comprehensively investigated in order to facilitate the deployment of these DG units in the distribution system. The objective of the work proposed in this thesis is to tackle some of the challenges associated with the increased penetration of renewable DG units into existing distribution systems. This includes the study of the impact of different renewable DG units on the supply adequacy of the distribution system, and the development of planning technique that optimally allocate renewable DG units into the distribution system. Furthermore, a methodology is proposed to check the feasibility of implementing energy storage system (ESS) into the distribution system to mitigate the problems associated with the high penetration of renewable DG units. These problems include the maximum reverse power flow limit, the equipment rating limit, and the voltage limit on each bus. The first step toward the accomplishment of this work is to model the random behaviour of the renewable resources (i.e. wind speed and solar irradiance). Here, different approaches are proposed to model the random behaviour of both wind speed and solar irradiance, either chronologically or probabilistically. Among those approaches are a novel technique of annual wind speed estimation based on a constrained Grey predictor, and a new implementation of the probability density function (pdf) of the clearness index so as to model solar irradiance using Monte Carlo Simulation (MCS). Supply adequacy of distribution systems is assessed based on well-being criteria during different modes of operation (i.e. grid-connected mode and islanding mode), using analytical and (MCS) techniques. During the grid-connected mode, from the load perspective, the substation transformers act as generating units. Therefore, supply adequacy of distribution systems is assessed by considering that the generating units of the distribution system are the substation transformers and the DG units. During the islanding mode of operation, the island is acting as a small autonomous power system (SAPS) and the most important issue during this mode of operation is to determine the probability of the island to be successful (the DG power output within the island matches the load) or a failure (there is a deficit in power generation). The focus of the model developed to optimally allocate the renewable DG units in existing distribution systems is to minimize annual energy losses and at the same time, avoid any violation of the system constraints under any operating condition. The methodology is based on generating a probabilistic generation-load model that combines all possible operating conditions of the renewable DG units with their probabilities, hence accommodating this model in a deterministic planning problem. The objective function of the planning formulation is to minimize annual energy losses; whereas the constraints include the voltage limits, the feeders’ capacity, the maximum penetration limit, and the discrete size of the available DG units. The objective of the methodology proposed for allocating an ESS into distribution systems with high penetration (greater than 20% of the feeder capacity) of renewable energy is to maximize the benefits for both the DG owner and the utility. This is done by sizing the ESS to accommodate the entire surplus of renewable energy, and then allocating it within the system in order to minimize the annual cost of the electricity.

New ideas and solutions are necessary to face challenges in the electricity industry. The application of electricity storage systems (ESS) can improve the quality and stability of the existing electricity network. ESS can be used for peak shaving, instead of installing new generation or transmission units, renewable energy time-shift and many other services. There are few ESS technologies existing today: mechanical, electrical and electrochemical storage systems. Flow batteries are electrochemical storage systems which use electrolyte that is stored in a tank separated from the battery cell. Electrochemistry is very important to understand how a flow battery functions and how it stores electric energy. The functioning of a flow battery is based on reduction and oxidation reactions in the cell. To estimate the voltage of a cell the Nernst equation is used. It tells how the half-cell potential changes depending on the change of concentration of a substance involved in an oxidation or reduction reaction. The first flow battery was invented in the 1880’s, but was forgotten for a long time. Further development was revived in the 1950’s and 1970’s. A flow battery consists of two parallel electrodes separated by an ion exchange membrane, forming two half-cells. The electro-active materials are stored externally in an electrolyte and are introduced into the device only during operation. The vanadium redox battery (VRB) is based on the four possible oxidation states of vanadium and has a standard potential of 1.23 V. Full ionic equations of the VRB include protons, sulfuric acid and the corresponding salts. The capital cost of a VRB is approximately 426 $/kW and 100 $/kWh. Other flow batteries are polysulfide-bromine, zinc bromine, vanadium-bromine, iron-chromium, zinc-cerium, uranium, neptunium and soluble lead-acid redox flow batteries. Flow batteries have long cycle life and quick response times, but are complicated in comparison with other batteries. / Nya idéer och lösningar är nödvändiga för att möta utmaningarna i elbranschen. Användningen av elektriskt lagringssystem (ESS) kan förbättra kvalitén och stabiliteten av det nuvarande elnätet. ESS kan användas till toppbelastningsutjämning, istället för att installera nya produktions eller kraft överförnings enheter, förnybar energi tidsförskjutning och många andra tjänster. I dagsläget finns det få olika ESS: Mekaniska, elektriska och elektrokemiska lagringssystem. Flödesbatterier tillhör kategorin elektrokemiska lagringssystem som använder sig utav elektrolyt som är lagrad i en tank separerad från battericellen. För att kunna förstå hur flödesbatteriernas funktioner och på vilket sätt som dem lagrar elektriskt energi är det viktigt att kunna elektrokemi. Flödesbatteriernas funktion är baserad på reduktions och oxidations reaktioner i cellen. Nernsts ekvation används för att kunna uppskatta voltantalet i en cell. Nernsts ekvation säger hur halvcell potentialen ändras beroende av ändringen av koncentrationen av ämnet involverat i oxidations eller reduktions reaktionen. Det första flödesbatteriet uppfanns 1880-talet, men blev bortglömt under en lång tid. Vidare utveckling förnyades under 1950 och 1970-talet. Ett flödesbatteri består utav två parallella elektroder som är separerade utav ett jonbytes membran vilket formar två halvceller. Dem elektroaktiva materialen är lagrade externt i elektrolyt och är införs bara i anordningen under användning. Vanadium redox batteriet (VRB) är baserat på dem fyra möjliga oxidations tillstånden av vanadium och har en standard potential på 1.23 V. Fullt joniska ekvationer av VRB inkluderar protoner, svavelsyra och deras motsvarande salter. Kapitalkostnaden av ett VRB är ungefär 426 $/kW och 100 $/kWh. Det finna andra flödesbatterier som är polysulfide-brom, zink-brom, vanadium-brom, järn-krom, uran, neptunium och löslig blysyre redox flödesbatterier. Flödesbatterier har en lång omloppstid samt en snabb svarstid men är komplicerade jämfört med andra batterier.

With power system restructuring, continuous growth of demand, and deregulation, small, scattered generators referred to as Distributed Generation (DG) are predicted to play a key role in the power distribution system. Moreover, among the different types of DG units, it is widely accepted that renewable DG units are the key to a sustainable energy supply infrastructure, since they are both inexhaustible and non-polluting. However the intermittent nature and the uncertainties associated with the renewable resources create special technical and economical challenges that have to be comprehensively investigated in order to facilitate the deployment of these DG units in the distribution system. The objective of the work proposed in this thesis is to tackle some of the challenges associated with the increased penetration of renewable DG units into existing distribution systems. This includes the study of the impact of different renewable DG units on the supply adequacy of the distribution system, and the development of planning technique that optimally allocate renewable DG units into the distribution system. Furthermore, a methodology is proposed to check the feasibility of implementing energy storage system (ESS) into the distribution system to mitigate the problems associated with the high penetration of renewable DG units. These problems include the maximum reverse power flow limit, the equipment rating limit, and the voltage limit on each bus. The first step toward the accomplishment of this work is to model the random behaviour of the renewable resources (i.e. wind speed and solar irradiance). Here, different approaches are proposed to model the random behaviour of both wind speed and solar irradiance, either chronologically or probabilistically. Among those approaches are a novel technique of annual wind speed estimation based on a constrained Grey predictor, and a new implementation of the probability density function (pdf) of the clearness index so as to model solar irradiance using Monte Carlo Simulation (MCS). Supply adequacy of distribution systems is assessed based on well-being criteria during different modes of operation (i.e. grid-connected mode and islanding mode), using analytical and (MCS) techniques. During the grid-connected mode, from the load perspective, the substation transformers act as generating units. Therefore, supply adequacy of distribution systems is assessed by considering that the generating units of the distribution system are the substation transformers and the DG units. During the islanding mode of operation, the island is acting as a small autonomous power system (SAPS) and the most important issue during this mode of operation is to determine the probability of the island to be successful (the DG power output within the island matches the load) or a failure (there is a deficit in power generation). The focus of the model developed to optimally allocate the renewable DG units in existing distribution systems is to minimize annual energy losses and at the same time, avoid any violation of the system constraints under any operating condition. The methodology is based on generating a probabilistic generation-load model that combines all possible operating conditions of the renewable DG units with their probabilities, hence accommodating this model in a deterministic planning problem. The objective function of the planning formulation is to minimize annual energy losses; whereas the constraints include the voltage limits, the feeders’ capacity, the maximum penetration limit, and the discrete size of the available DG units. The objective of the methodology proposed for allocating an ESS into distribution systems with high penetration (greater than 20% of the feeder capacity) of renewable energy is to maximize the benefits for both the DG owner and the utility. This is done by sizing the ESS to accommodate the entire surplus of renewable energy, and then allocating it within the system in order to minimize the annual cost of the electricity.

This thesis addresses the future of sustainable energy distribution and transportation in the United States. Predictions of future energy and transportation demands promote localized energy as the most likely situation. Existing proposals outlining the benefits of decentralized energy production fail to engage architecture. Cities will require new architectural typologies that can integrate new energy infrastructure in the city. Los Angeles, the archetype of the decentralized American city, is introduced as a case study. The city is examined at multiple scales for the integration of a decentralized electricity network and an efficient transportation infrastructure. Siting the proposed facilities capitalizes on new and existing transportation infrastructures and local energy resources. The new electricity-transportation infrastructure is adapted to a decentralized network functioning on principles of ecosystems and energy economics at an urban scale. Energy storage is paired with multi-modal transportation to develop new architectural and urban typologies. This enables the decentralized urban proposal to function as a network exhibiting mutually beneficial characteristics.

Global environmental concerns associated with conventional energy generation have led to the rapid growth of wind energy applications in electric power systems. Growing demand for electrical energy and concerns associated with limited reserves of fossil fuels are also responsible for the development and increase in wind energy utilization. Many jurisdictions around the world have set high wind penetration targets in their energy generation mix.<p> The contribution of wind farms to the overall system reliability is limited by the uncertainty in power output from the highly variable energy source. High wind penetration can lead to high risk levels in power system reliability and stability. In order to maintain the system stability, wind energy dispatch is usually restricted and energy storage is considered to smooth out the fluctuations and improve supply continuity. The research work presented in this thesis is focused on developing reliability models for evaluating the benefits associated with wind power and energy storage in electric power generating systems. An interactive method using a sequential Monte Carlo simulation technique that incorporates wind farm and energy storage operating strategies is developed and employed in this research. Different operating strategies are compared and the resulting benefits are evaluated. Important system impacts on the reliability benefits from wind power and energy storage are illustrated. Hydro facilities with energy storage capability can alleviate the impact of wind power fluctuations and also contribute to system adequacy. A simulation technique for an energy limited hydro plant and wind farm coordination is developed considering the chronological variation in the wind, water and the energy demand. The IEEE four-state model is incorporated in the developed technique to recognize the intermittent operation of hydro units. Quantitative assessment of reliability benefits from effective utilization of wind and water resources are conducted through a range of sensitivity studies. The information provided and the examples illustrated in this thesis should prove useful to power system planners and wind developers to assess the reliability benefit from utilizing wind energy and energy storage and the coordination between wind and hydro power in electric power systems.