<p>In this research, a Split-Shaft Wind Energy Conversion System (SS-WECS) is investigated</p> <p>to improve the performance and cost of the system and reduce the wind power</p> <p>uncertainty influences on the power grid. This system utilizes a lightweight Hydraulic Transmission</p> <p>System (HTS) instead of the traditional gearbox and uses a Doubly-Fed Induction</p> <p>Generator (DFIG) instead of a synchronous generator. This type of wind turbine provides</p> <p>several benefits, including decoupling the shaft speed controls at the turbine and the generator.</p> <p>Hence, maintaining the generator’s frequency and seeking maximum power point</p> <p>can be accomplished independently. The frequency control relies on the mechanical torque</p> <p>adjustment on the hydraulic motor that is coupled with the generator. This research provides</p> <p>modeling of an SS-WECS to show its dependence on mechanical torque and a control</p> <p>technique to realize the mechanical torque adjustments utilizing a Doubly-Fed Induction</p> <p>Generator (DFIG). To this end, a vector control technique is employed, and the generator</p> <p>electrical torque is controlled to adjust the frequency while the wind turbine dynamics</p> <p>influence the system operation. The results demonstrate that the generator’s frequency is</p> <p>maintained under any wind speed experienced at the turbine.</p> <p>Next, to reduce the size of power converters required for controlling DFIG, this research</p> <p>introduces a control technique that allows achieving MPPT in a narrow window of generator</p> <p>speed in an SS-WECS. Consequently, the size of the power converters is reduced</p> <p>significantly. The proposed configuration is investigated by analytical calculations and simulations</p> <p>to demonstrate the reduced size of the converter and dynamic performance of the</p> <p>power generation. Furthermore, a new configuration is proposed to eliminate the Grid-</p> <p>Side Converter (GSC). This configuration employs only a reduced-size Rotor-Side Converter</p> <p>(RSC) in tandem with a supercapacitor. This is accomplished by employing the hydraulic</p> <p>transmission system (HTS) as a continuously variable and shaft decoupling transmission</p> <p>unit. In this configuration, the speed of the DFIG is controlled by the RSC to regulate the</p> <p>supercapacitor voltage without GSC. The proposed system is investigated and simulated in</p> <p>MATLAB Simulink at various wind speeds to validate the results.</p> <p>Next, to reduce the wind power uncertainty, this research introduces an SS-WECS where the system’s inertia is adjusted to store the energy. Accordingly, a flywheel is mechanically</p> <p>coupled with the rotor of the DFIG. Employing the HTS in such a configuration allows the</p> <p>turbine controller to track the point of maximum power (MPPT) while the generator controller</p> <p>can adjust the generator speed. As a result, the flywheel, which is directly connected</p> <p>to the shaft of the generator, can be charged and discharged by controlling the generator</p> <p>speed. In this process, the flywheel energy can be used to modify the electric power generation</p> <p>of the generator on-demand. This improves the quality of injected power to the</p> <p>grid. Furthermore, the structure of the flywheel energy storage is simplified by removing</p> <p>its dedicated motor/generator and the power electronics driver. Two separate supervisory</p> <p>controllers are developed using fuzzy logic regulators to generate a real-time output power</p> <p>reference. Furthermore, small-signal models are developed to analyze and improve the MPPT</p> <p>controller. Extensive simulation results demonstrate the feasibility of such a system and its</p> <p>improved quality of power generation.</p> <p>Next, an integrated Hybrid Energy Storage System (HESS) is developed to support the</p> <p>new DFIG excitation system in the SS-WECS. The goal is to improve the power quality</p> <p>while significantly reducing the generator excitation power rating and component counts.</p> <p>Therefore, the rotor excitation circuit is modified to add the storage to its DC link directly.</p> <p>In this configuration, the output power fluctuation is attenuated solely by utilizing the RSC,</p> <p>making it self-sufficient from the grid connection. The storage characteristics are identified</p> <p>based on several system design parameters, including the system inertia, inverter capacity,</p> <p>and energy storage capacity. The obtained power generation characteristics suggest an energy</p> <p>storage system as a mix of fast-acting types and a high energy capacity with moderate</p> <p>acting time. Then, a feedback controller is designed to maintain the charge in the storage</p> <p>within the required limits. Additionally, an adaptive model-predictive controller is developed</p> <p>to reduce power generation fluctuations. The proposed system is investigated and simulated</p> <p>in MATLAB Simulink at various wind speeds to validate the results and demonstrate the</p> <p>system’s dynamic performance. It is shown that the system’s inertia is critical to damping</p> <p>the high-frequency oscillations of the wind power fluctuations. Then, an optimization approach</p> <p>using the Response Surface Method (RSM) is conducted to minimize the annualized</p> <p>cost of the Hybrid Energy Storage System (HESS); consisting of a flywheel, supercapacitor, and battery. The goal is to smooth out the output power fluctuations by the optimal</p> <p>size of the HESS. Thus, a 1.5 MW hydraulic wind turbine is simulated, and the HESS is</p> <p>configured and optimized. The direct connection of the flywheel allows reaching a suitable</p> <p>level of smoothness at a reasonable cost. The proposed configuration is compared with the</p> <p>conventional storage, and the results demonstrate that the proposed integrated HESS can</p> <p>decrease the annualized storage cost by 71 %.</p> <p>Finally, this research investigates the effects of the reduced-size RSC on the Low Voltage</p> <p>Ride Through (LVRT) capabilities required from all wind turbines. One of the significant</p> <p>achievements of an SS-WECS is the reduced size excitation circuit. The grid side converter is</p> <p>eliminated, and the size of the rotor side converter (RSC) can be safely reduced to a fraction</p> <p>of a full-size excitation. Therefore, this low-power-rated converter operates at low voltage</p> <p>and handles the regular operation well. However, the fault conditions may expose conditions</p> <p>on the converter and push it to its limits. Therefore, four different protection circuits are</p> <p>employed, and their effects are investigated and compared to evaluate their performance.</p> <p>These four protection circuits include the active crowbar, active crowbar along a resistorinductor</p> <p>circuit (C-RL), series dynamic resistor (SDR), and new-bridge fault current limiter</p> <p>(NBFCL). The wind turbine controllers are also adapted to reduce the impact of the fault</p> <p>on the power electronic converters. One of the effective methods is to store the excess energy</p> <p>in the generator’s rotor. Finally, the proposed LVRT strategies are simulated in MATLAB</p> <p>Simulink to validate the results and demonstrate their effectiveness and functionality.</p>

<p>The ongoing and rapidly accelerating integration of inverter-based resources (IBRs), such as solar panels, into power distribution systems has heightened the importance of computational tools that can be used to study the dynamics of such systems. IBRs use power electronics to interface the energy sources to the grid, thereby introducing faster dynamics than their electromechanical counterparts, which could lead to instabilities in distribution systems and microgrids. Hence, there is a need for conducting simulations of distribution systems containing large numbers of single- and three-phase inverters, which could be operating under either grid-following or grid-forming modes.</p> <p>A key objective of this thesis is to derive detailed, high-fidelity models of inverters and their controls in the context of unbalanced distribution networks. In addition, a diesel synchronous generator model is derived, for the sake of completeness. The main contribution of this work is that these models are developed for use in a novel simulation toolbox called Dynamic Simulation Tool using a Sparse Tableau Approach in Python, DynaSTPy (pronounced dynasty). This thesis outlines how the components can be modeled in the sparse tableau framework as electrical networks with topology described using a node-branch incidence matrix. In addition, the thesis explains how controller dynamics and constraints can be handled within this framework. These models are tailored to seamlessly integrate into the DynaSTPy toolbox. The proposed approach can be readily extended to model other such components in the future.</p>

Yes / This chapter provides a background on the roles of international arbitration as an important mechanism for dispute resolution in Africa’s dynamic and evolving energy and mining sectors. Given its abundant endowment with renewable and non-renewable energy sources, Africa has for several decades provided significant opportunities for international energy companies to spearhead energy production activities and investments in the production, distribution, and sale of energy. Despite these investment opportunities, entrants into energy markets in Africa often face legal risks that pose monumental threats to the economic viability of investments. If not properly mitigated and addressed, such risks may result in complex and protracted legal disputes. Over the last decade, arbitration has emerged as a key mechanism for dispute resolution in Africa’s growing energy industry. After providing an overview of the history, nature, and scope of energy arbitration in Africa, this chapter examines the drivers and sources of energy disputes in Africa’s energy and mining sectors and how the rise in arbitration provisions in energy contracts is shaping legal responses to such risk drivers. It analyzes how the full value of arbitration can be maximized as a tool for achieving fair, timely, efficient, and effective dispute resolution in Africa’s energy sector, especially in light of ongoing energy transitions.

As the UK energy sector moves to a greater contribution from low-carbon and renewable sources it faces significant challenges in delivering affordability, security of supply and sustainability. Although hydropower in Scotland emerged on a large scale in the mid-20th century against an influential, changing wider context of energy policy, environmental regulation and debate, it is now subject to an evolving renewables agenda. This further shapes the national and scheme level characteristics of hydropower and in turn outcomes for the water environment. Contingent upon these considerations, hydropower regulation must now deliver on EU obligations to protect and improve the ecological status of water bodies, whilst also supporting domestic efforts to meet high profile binding renewable energy targets. Yet, despite an acknowledged potential for energy policy to constrain the delivery of water policy objectives, there is little policy harmonisation between disciplines. As Scotland orientates itself as a leader in Europe on climate change, transitioning to increasing amounts of renewable generation across a handful of technologies, there is a gap in knowledge about how specific renewable policies and trends can influence hydropower sustainability outcomes and regulatory challenges. This thesis therefore contributes an innovative and timely critical examination of the effect a changing wider renewable energy and policy context has on hydropower sustainability in Scotland, at a scheme and national level. This research uses an interdisciplinary, temporal analysis to identify linkages and create dialogue between disciplines and scales, informing the pursuit of sustainable renewable energy through policy and regulation in a changing world. It finds firstly, that the changing national generation mix towards an increased contribution from renewable sources, including potentially intermittent technologies such as wind power, has contributed to an alteration in the operational characteristics and reservoir variability profile of Cruachan pumped-storage scheme, presenting positive outcomes for reservoir littoral habitats. Secondly, it finds that whilst not operating in isolation, renewable energy incentive policies, through their eligibility criteria, financial reward frameworks and timing, influence hydropower characteristics and sustainability challenges, providing trade-offs but also synergies for hydropower regulation. Finally, it finds that there is a degree of divergence in hydropower outcomes and challenges in Scotland and Norway, due to the characteristics and especially interaction of wider contextual elements such as topography, profile of precipitation input, national energy needs and the role of regional and municipal government. By highlighting these linkages, this thesis is of value to energy policy and environmental regulation in Scotland and across the EU, and is seen as a first step in addressing these uncertainties and supporting a more integrated and sustainable hydropower and renewables governance framework.

The increasing share of renewable energies in the power sector influences the economic viability of investments in new conventional power plants. Many studies have investigated these issues by considering power plant operation or the long-term development of the power plant fleet. However, power plant decommissioning, investment and operation are intrinsically linked. This doctoral thesis therefore presents a modelling framework for an integrated consideration of power plant decommissioning, investment and operation. In a case study focusing on Germany, the effects of the integration of renewable energies on power plant decommissioning, investment and operation are evaluated in the context of different assumptions regarding the remaining lifetime of nuclear power plants. With regard to the use of nuclear power, a phase-out scenario and a scenario with lifetime extension of nuclear power plants (by on average 12 years) are considered. The results show that static decommissioning (i.e. considering fixed technical lifetimes) underestimates the capacity available in the power sector in the scenario without lifetime extension since retrofit measures (versus decommissioning) are not taken into account. In contrast, capacity available in the case of nuclear lifetime extension is overestimated since mothballing (versus regular operation) is not considered. If the impact on decommissioning decisions of profit margins accrued during power plant operation are considered (“dynamic decommissioning”), the electricity price reduction effect due to a lifetime extension is reduced by more than half in comparison to static decommissioning. Scarcity situations do not differ significantly between the scenarios with and without lifetime extension with dynamic decommissioning; in contrast, there is a significantly higher need for imports without lifetime extension with static decommissioning. The case study demonstrates that further system flexibility is needed for the integration of renewable energies. It can be further concluded that the share of flexible power plants is higher with the phase-out of nuclear power plants. With regard to the decommissioning dynamics, the phase-out can be considered as beneficial for the economic viability of fossil power plants. Furthermore, the phase-out does not, overall, lead to environmental disadvantages in the medium term, but may be beneficial in the long run since lock-in effects are avoided. Further research is required with regard to the consideration of future flexibility options and a new market design. / Der steigende Anteil erneuerbarer Energien beeinflusst die Wirtschaftlichkeit von Investitionen in neue konventionelle Kraftwerke. Zahlreiche Studien haben diese Aspekte in Bezug auf den Kraftwerksbetrieb oder die langfristige Entwicklung des Kraftwerksparks untersucht. Stilllegungen, Investitionen und Betrieb im Kraftwerkspark bedingen jedoch einander. Aus diesem Grund wird in dieser Doktorarbeit ein Modellierungsansatz für eine integrierte Betrachtung von Kraftwerksstilllegung, -investition und -betrieb vorgestellt. In einer Fallstudie für Deutschland werden die Auswirkungen einer Integration erneuerbarer Energien auf Kraftwerksstilllegung, -investition und -betrieb im Zusammenhang mit unterschiedlichen Annahmen über die Restlaufzeit von Kernkraftwerken untersucht. Bezogen auf die Nutzung der Kernenergie wird hierbei ein Ausstiegsszenario sowie ein Laufzeitverlängerungsszenario (Verlän-gerung der Laufzeit um durchschnittlich 12 Jahre) betrachtet. Die Ergebnisse zeigen, dass die statische Stilllegung (d.h. die Betrachtung fester technischer Lebensdauern) im Fall eines Verzichts auf die Laufzeitverlängerung die im Kraftwerkspark verfügbare Leistung unterschätzt, da Retrofit-Maßnahmen (im Vergleich zur Stilllegung) nicht berücksichtigt werden. Die verfügbare Leistung im Falle einer Laufzeitverlängerung wird dagegen überschätzt, da die Möglichkeit der Kaltreserve (im Vergleich zum regulären Betrieb) vernachlässigt wird. Werden die Rückwirkungen der im Betrieb erwirtschaftbaren Deckungsbeiträge auf Stilllegungsentscheidungen (“dynamische Stilllegung”) betrachtet, so wird der strompreissenkende Effekt durch die Laufzeitverlängerung im Vergleich zur statischen Stilllegung mehr als halbiert. Knappheitssitutationen unterscheiden sich nicht wesentlich mit und ohne Laufzeitverlängerung im Fall der dynamischen Stilllegung, während bei statischer Stilllegung ohne Laufzeitzeitverlängerung ein deutlich größerer Importbedarf besteht. Die Fallstudie zeigt, dass weitere Systemflexibilitäten für die Integration erneuerbarer Energien benötigt werden. Der Anteil flexibler Kraftwerke ist größer im Fall des Kernenergieausstiegs. Der Kernenergieausstieg wirkt sich in Bezug auf die Stilllegungsdynamik positiv auf die Wirtschaftlichkeit fossiler Kraftwerke aus. Insgesamt führt der Kernenergieausstieg zu keinen mittelfristig nachteiligen Umwelteffekten, er kann sich jedoch langfristig positiv auswirken, da Lock-in-Effekte vermieden werden. Es besteht weiterer Forschungsbedarf in Bezug auf die Berücksichtigung künftiger Flexibilitätsoptionen und ein neues Marktdesign.

There is much interest in the protection of the ecosystem within the oil and gas industry. This is particularly significant in the countries of the Middle East where the oil and gas sectors contribute a large part, in some cases all of the country economies. A case study research analysis into the Lean and Green principles of one of the State of Kuwait organisations could offer the country huge potential and could benefit other Arabian Gulf countries. In the chosen country (Kuwait), Kuwait Oil Company (KOC) has no other outlet for its business apart from oil and gas production. It also does not concern itself with other support business that could contribute to Kuwait's economy.

Les problèmes environnementaux et économiques, engendrés par l’usage des produits pétroliers, et la pénurie de ces énergies fossiles ont conduit à rechercher d’autres sources d’énergies, renouvelables et respectueuses de l’environnement. Nombre de ces sources sont intermittentes et nécessitent de prévoir des solutions de stockage. Le gaz de dihydrogène apparait comme un bon candidat pour remplir cette fonction. L’élément hydrogène, abondant dans la nature, présente sous sa forme gazeuse un pouvoir calorifique de 140 MJ/kg, soit 2,5 fois celui de l’essence. La filière ’hydrogène’ s’appuie sur 3 piliers : la production, le stockage-la distribution et l’utilisation. Le stockage d’hydrogène est traditionnellement réalisé par compression, sous des pressions allant de quelques bars à plusieurs centaines, et par liquéfaction à 20 K. La faible densité volumique de ces deux types de stockage (42 et 70 kgH2/m3) associée à de sérieux problèmes de sécurité et de conception mécanique, rend le stockage solide dans les alliages métalliques particulièrement pertinent pour certaines applications. Cette solution favorise le développement de réservoirs de conception sûre, compacts et ayant une grande densité volumique de 120 kgH2/m3 pour les alliages TiFe par exemple. Ce type d’hydrure a été retenu dans le cadre de ce travail parce qu’il présente des températures et pressions d’utilisation relativement proches des conditions ambiantes, mais aussi parce qu’il ne contient pas de terre rare d’utilisation relativement proches des conditions ambiantes, mais aussi parce qu’il ne contient pas de terre rare. La présente étude vise à caractériser et modéliser le comportement d’hydruration/déshydruration de l’alliage TiFe0.9Mn0.1, en vue d’améliorer ses performances lorsqu’il est intégré à un système de stockage. Dans un premier temps, nous nous sommes attachés à caractériser expérimentalement l’alliage TiFe0.9Mn0.1 sous forme de poudre en le décrivant sur les plans morphologique, chimique et thermodynamique. Ensuite, deux stratégies d’amélioration ont été testées, la première repose sur un traitement mécanique par broyage planétaire à billes, la deuxième considère un traitement thermochimique à température et durée de maintien données. Ces deux stratégies ont permis d’accélérer le processus d’activation de la poudre, mais le broyage planétaire à billes a détérioré de façon notable la cinétique apparente de désorption. Le traitement thermochimique n’a quant à lui pas dégradé les domaines d’équilibre et n’a donc pas eu d’effet néfaste sur les cinétiques de réaction. Les deux paramètres les plus importants de ce traitement, température et temps de maintien, ont été optimisés. D’autres paramètres restent à affiner.[...]La conception d’un système de stockage solide d’hydrogène exige la bonne compréhension des aspects macroscopiques, mais aussi microscopiques, de la réaction d’hydruration, et requiert donc des recherches complémentaires pour trouver de nouveaux axes d’amélioration de ses performances. / He environmental and economic problems caused by the use of petroleum products and the scarcity of these fossil fuels have led to the search for alternative sources of energy, which are renewable and respectful of the environment. Many of these sources are intermittent and require storage solutions. Hydrogen gas appears as a good candidate for this function. The hydrogen element, abundant in nature, has in its gaseous form a calorific value of 140 MJ / kg, i.e. 2.5 times that of gasoline. The 'hydrogen' sector is based on 3 pillars: production, storage, distribution and use. The storage of hydrogen is traditionally carried out by compression, under pressures ranging from a few bars to several hundreds, and by liquefaction at 20 K. The low density of these two types of storage (42 and 70 kgH2 / m3) associated with serious problems of safety and mechanical design, make solid storage in metal alloys particularly relevant for some applications. This solution favors the development of safe, compact design tanks with a high density of 120 kgH2/m3for TiFe alloys, for example. This type of hydride has been retained in this work because it has operating conditions of temperatures and pressures that are relatively close to ambient conditions, and also because it does not contain rare earth elements. The aim of this study is to characterize and model the hydriding/dehydriding behavior of the TiFe0.9Mn0.1 alloy, in order to improve its performance when it is integrated into a storage system. We first tried to characterize the alloy TiFe0.9Mn0.1 in powder form by describing it morphologically, chemically and thermodynamically. Then, two strategies of improvement were tested, the first one based on a mechanical treatment by planetary ball milling, the second considers a thermochemical treatment at given temperature and duration. Both strategies accelerated the process of powder activation, but the planetary ball milling significantly impaired the apparent desorption kinetics. The thermo-chemical treatment did not degrade the equilibrium domains and thus did not have an adverse effect on the reaction kinetics. The two most important parameters of this treatment, temperature and holding time, have been optimized. Other parameters remain to be refined.In addition to this experimental characterization, we have undertaken to describe the hydriding / dehydriding reaction macroscopically. The model allows to account for the thermodynamic response of the hydride within a reservoir. This work presents the results obtained on a tank containing 4 kg of TiFe0.9Mn0.1 powder when different hydrogen loading / unloading scenarios are considered: (i) loading / unloading under constant pressure, (ii) loading / unloading under an initial dose ( Method of Sievert), iii) loading / unloading under inlet or outlet flux of hydrogen. For each scenario, the effect of the coupling with a heat exchange system on the filling / emptying times is analyzed and optimal operating conditions are proposed. Finally, a sensitivity study using the Morris method is presented, and the most influential parameters of the model on the reaction rates are identified. The design of a solid hydrogen storage system requires a good understanding of the macroscopic as well as the microscopic aspects of the hydriding reaction and therefore requires further research to find new directions for improving its performance.

Ogni tecnologia produttiva ha un proprio profilo di dispacciamento ottimale che non dovrebbe essere alterato dall’ingresso delle intermittenti tecnologie rinnovabili per mantenere la migliore allocazione di prezzo e quantità. La nostra ricerca si focalizza sul mercato elettrico italiano. Considerando il comportamento di Edison Trading sul mercato, noi analizziamo se l’incremento di energia rinnovabile porta alla riduzione del prezzo e della produzione di energia grazie all’efficienza. I nostri principali risultati suggeriscono che le rinnovabili hanno un impatto negativo sulle quantità offerte. Gli impianti solari e di pompaggio portano ad un consistente incremento del prezzo elettrico; il contrario vale per le altre rinnovabili. La nostra analisi sul mercato italiano aggregato considera il comportamento di tutti gli operatori del mercato elettrico (quelli aventi consistenti e limitate quote di mercato) nel quindicesimo giorno di ogni mese nel periodo gennaio 2013 - giugno 2015. Possiamo aspettarci lo stesso risultato in termini di impatto sul prezzo e quantità, data la crescente potenza lorda eolica e solare? I nostri risultati empirici sottolineano che le tecnologie intermittenti possono solamente portare ad incrementi di prezzo, mentre i più grandi operatori di mercato (Enel, Eni ed Edison) utilizzano la tecnologia CCGT efficientemente, poichè producono quando il prezzo è più alto. / Each power plant has its own optimal dispatchable profile that should not be altered by the entrance of intermittent renewables to maintain the best allocation of price and quantity. Our research focuses on the Italian electricity market. Focusing on the market behaviour of Edison Trading, we investigate if the increase in renewable energy leads to a decrease in energy price and in energy production due to efficiency. Our main results suggest that renewables have a negative impact on the quantity supplied. Solar and pumped-storage technologies lead to a consistent increase in the electricity price, while the reverse is true for the other renewables. Our analysis on the aggregate Italian electricity market considers the behaviour of all electricity market operators (with low and high market shares) on the 15th day of each month in the period January 2013 - June 2015. Can we expect the same results in terms of the impact on price and quantity, given the increase in gross wind and solar power? Our empirical findings point out that the intermittent technologies can only lead to price increases, whereas the biggest market players (Enel, Eni and Edison) use CCGT technology efficiently since they produce when the price is higher.

Under the current climate emergency, the electricity industry is taking quick steps to introduce new technology and market processes that could contribute to the decarbonization of the power system. The creation of the energy attribute certificates more than two decades ago has allowed consumers to choose the origin of their electricity. This market instrument has provided a new tool for tracking carbon-free electricity. It is how corporates can reduce their market-based emissions under the Scope 2 Green House Gas Protocol, a practice called annual matching of certificates. However, there are new trends in green electricity procurement that intend to improve the current system. These are called 24/7 carbon-free electricity and emissionality. To bring added value, these new methodologies require more granularity, hourly or less, for both electricity market data and energy attribute certificates. This can be achieved with so-called granular certificates. This thesis intends to provide some answers to the implications at a corporate level, specifically for their carbon accounting exercises, of adopting these practices. Different industrial and commercial electricity consumer profiles are analyzed in several European countries for 2021 under four different scenarios: base, RE100, 24/7, and emissionality. The results show that using hourly grid carbon intensity, location-based emission can differ from annual calculations up to 7%. In addition, it exemplifies some of the inefficiencies of the current practice of yearly matching of certificates. In 2021, it required less than 1% of a company’s total electricity sourcing costs to certify that they are 100 % renewable, acquiring mainly unbundled certificates. For the case of bundled certificates linked to a specific technology, these costs increased to 2,60 % for the case of the Dutch wind. The 24/7 scenario shows the actual coverage of the renewable contracted sources after the implementation of 24/7 carbon-free electricity matching, ranging from values between 48% and 99 %, depending on the consumption profile, the location, and the contracted renewable sources portfolio. Finally, the emissionality scenario provides the tools to determine where to locate new renewable generation capacity to decrease the emissions as much as possible. The results show that, under specific circumstances, these values can be three times higher. This thesis promotes adopting 24/7 carbon-free electricity practices for attributional carbon accounting methodologies. Nevertheless, its definition should be reviewed to easily include emissionality studies when new carbon-free renewable capacity construction comes from corporations’ green procurement decisions. / Under den rådande klimatkrisen vidtar elbranschen snabba åtgärder för att introducera ny teknik och nya marknadsprocesser som kan bidra till minskade koldioxitutsläpp från elsystemet. Införandet av energiattributcertifikat för mer än tjugo år sedan har gjort det möljigt för konsumenterna att välja vad de vill köpa för el. Detta marknadsinstrument har tillhandahållit ett nytt verktyg för att spåra koldioxidfri el. Det är så företag kan minska sina marknadsbaserade utsläpp enligt Scope 2 Green House Gas Protocol, en praxis som kallas årlig matchning av certifikat. Det finns dock nya trender inom upphandling av grön el som avser att förbättra det nuvarande systemet. Dessa kallas 24/7 koldioxidfri el och emissionalitet. För att skapa ett mervärde kräver dessa nya metoder en ökad granularitet, timbasis eller mindre, för både elmarknadsdata och energiattributcertifikat. Detta kan åstadkommas med så kallade granulära certifikat. Denna rapport avser att ge några svar på konsekvenserna på företagsnivå, specifikt för deras koldioxidredovisningar, av att anta dessa metoder. Olika industriella och kommersiella elkonsumentprofiler analyseras i flera europeiska länder för 2021 under fyra olika scenarier: bas, RE100, 24/7 och emissionalitet. Resultaten visar att då man använder koldioxidsintensitet för elnätet kan de platsberoende utsläppen skilja sig från de årliga beräkningarna med upp till 7%. Dessutom visas exempel på några av ineffektiviteterna i det nuvarande systemet med årlig matchning av certifikat. År 2021 krävdes det mindre än 1% av ett företags totala elkostnad för att intyga att de är 100% förnybara, huvudsakligen med separata certifikat. För paketerade certifikat kopplade till en specifik teknik ökade dessa kostnader till 2,60 % för fallet med holländska vindkraft. 24/7-scenariot visar att efter man implementerat 24/7 koldioxidfri elmatchning så varierar den faktiska täckningen av kontrakterad förnybar produktion mellan 48% och 99% beroende på förbrukningsprofil, lokalisering och vilka förnybara källor som kontrakterats. Slutligen tillhandahåller emissionalitetsscenariet verktygen för att bestämma var ny förnybar produktionskapacitet ska placeras för att minska koldioxidutsläppen så mycket som möjligt. Resultaten visar att under specifika omständigheter kan dessa värden vara tre gånger större. Det här examensarbetet främjar användningen av systemet för 24/7 koldioxidfri el för attributionella koldixodidredovisningsmetoder. Dess definition bör dock ses över för att enkelt inkludera emissionalitetsstudier då ny koldioxidfri av förnybar produktionskapacitet baserat på företags gröna upphandlingsbeslut.

<div> Porous lithium ion battery (LIB) electrodes are comprised of electrochemically active material particles that store lithium and a surrounding conductive binder, liquid electrolyte, carbon black mixture that facilitates ionic and electronic transport. Typically, lithium diffusivity is several orders of magnitude smaller in the active material as compared to the surrounding electrolyte, making the electrode microstructure a governing factor in determining the balance between its lithium storage capacity and transport rate. Here, the effects of microstructure on the performance of LIBs are systematically analyzed at three length scales - the single particle length scale, the spatially resolved multiple particle length scale, and the porous electrode layer (homogenized) length scale. At the single particle length scale, a thermodynamically consistent variational framework is presented to examine the effects of crystallographic anisotropy, crystallographic texture, grain size, and grain morphology on the LiNi_1/3Mn_1/3Co_1/3O₂ (NMC111) chemistry. The theory was extended to the spatially resolved multiple particle length scale and the porous electrode layer length scale to explain the microstructural origin of experimentally observed instances of apparent phase separation in NMC111. At the electrode length scale, a data driven framework is presented to evaluate the electrochemical performance of a wide range of particle morphologies and battery architectures. Specifically, microstructural characteristics of 53 356 microstructures are assessed, and strategies to optimize electrode design parameters such as active particle morphology, spatial orientation, electrode porosity, and cell thickness are presented.</div><p></p>