L'utilisation de nouveaux vecteurs énergétiques comme alternative aux combustibles fossiles et nucléaires est nécessaire pour la transition vers les énergies renouvelables. Ces sources d'énergie intermittentes peuvent être stockées dans des carburants, tels que le dihydrogène qui se distingue par sa densité énergétique. L'oxydation contrôlée de H2 peut être effectuée dans des piles à combustible, qui oxydent l'hydrogène à l'anode et réduisent l'oxygène à la cathode pour former de l'eau et de la chaleur comme seuls produits de la réaction. Ces technologies, matures, emploient des métaux du groupe du platine comme catalyseurs à l'anode et à la cathode. Cependant, alors que les demandes énergétiques mondiales ne cessent d'augmenter, ces ressources limitées ne seront pas suffisantes pour une adoption mondiale de l'hydrogène comme vecteur énergétique. Dans ce travail, des matériaux contenant des catalyseurs bio-inspirés, sans métaux nobles pour l'oxydation de H2 sont optimisés et intégrés dans des piles à combustible fonctionnelles. Leur comportement dans des conditions technologiques est étudié et comparé à celui de l'état de l'art des catalyseurs au platine. Les matériaux les plus performants sont caractérisés en détail par diverses techniques, donnant des pistes pour une optimisation future ainsi qu'un aperçu de ce que requièrent les tests de performance de nouveaux matériaux catalytiques. / The use of new energy vectors as alternatives to the fossil and nuclear fuels is necessary for the transition to renewable energies. These intermittent energy sources can be stored in fuels, such as hydrogen gas which stands out for its energy density and participation in the virtuous water splitting cycle. Controlled H2 oxidation can be done in so-called fuel cells, which oxidize hydrogen at the anode and reduce oxygen at the cathode to form water and heat as the sole products of the reaction. Those mature technologies employ platinum group metals as catalysts at both the anode and cathode. However, as worldwide energy demands keep increasing, these limited resources will not be sufficient for a worldwide adoption of H2 as an energy vector. In this work, materials containing noble metal free, bio inspired catalysts for H2 oxidation are optimized and integrated in functional fuel cells. Their behaviour in technologically-relevant conditions is studied and compared to that of state of the art platinum catalysts. The best performing materials are thoroughly characterized with various techniques including advanced electrochemistry, yielding leads for further optimization as well as insight on the benchmarking of novel catalytic materials.

Dans cette thèse, on étudie le phénomène de localisation d'Anderson des opérateurs de Schrödinger à N particules qui englobe aussi bien la localisation exponentielle des fonctions propres que la localisation dynamique. Dans un premier temps, on considère le modèle d'Anderson discret multi- particulaire avec un potentiel aléatoire à valeurs indépendantes et identiquement distribuées i.i.d. dont la distribution commune est au moins log-Höldérienne et une interaction de courte portée. On établit pour ce modèle la localisation d'Anderson pour les énergies susamment proches du bas du spectre après avoir montré qu'il est non-aléatoire. D'autre part, on montre que la localisation complète des systèmes mono- particulaires s'étend aux systèmes multi-particulaires ayant une interaction globale susamment faible et pour un désordre arbitraire. Pour ce résultat, l'existence d'une densité bornée de la distribution commune des variables aléatoires i.i.d. est nécessaire et on le montre pour des interactions ayant une forme très générale mais bornées. Les résultats sont démontrés à l'aide de l'adaptation aux systèmes multi- particulaires de l'analyse multi-échelle à énergie variable qui permet de traiter des distributions singulières contrairement à la méthode des moments fractionnaires. Les estimées de Wegner intervenant notamment dans l'analyse multi-échelle sont établies pour des cubes vériant une propriété de séparabilité en utilisant le Lemme de Stollmann. On démontre également l'estimée de Combes-Thomas qui joue un rôle important dans l'analyse des énergies extrêmes. / In this thesis, we study for the N-particles Schrodinger operators the Anderson localization phenomenon which consists of both exponential localization of eigenfunctions and dynamical localization. We rst consider the discrete multi-particle Anderson model with a short range interaction and a random potential whose values are independent and identically distributed i.i.d. with a log-Hölder continuous common probability distribution function. For such model, we show that the bottom of its spectrum is non-random and prove the Anderson localization for energies suciently close to the spectral edge. On the other hand, we establish that the complete localization from singleparticle systems extends to multi-particle systems with suciently weak interaction at arbitrary disorder and for absolute continuous probability distribution function of the i.i.d random variables. The results are proved by an adaptation to multi-particle systems of the vari- able energy multi-scale analysis which allows singular distributions instead of the fractional moments method. Wegner bounds, useful for the multi-scale analysis are proved for separable cubes using the Stollmann's Lemma. We also prove the Combes-Thomas estimate which plays an important role in the analysis of extreme energies.

The objective of this thesis is the definition and development of a comprehensive methodology of energy planning for areas isolated from the mains, considering not only the energy context of the country and its development towards a sustainable scenario, but also studying the potential of renewable generation in the remote area under study, the ability for demand management and the socio-economic aspects involved in the final decision on what renewable energy solution would be the most appropriate in accordance with the characteristics of the location. The research work is organized into three major phases. The first one defines the algorithm of analysis of the context energy of the country and its evolution towards a future energy scenario based on renewable energies. A second phase which analyzes the best configurations of hybrid renewable systems capable of responding to energy needs in the area, sorting them based on their net present value. And a third one introducing the method of multi-criteria analysis which allows to select, from among all possible configurations identified in the previous stage, the most appropriate to the needs and characteristics of the area to study, taking into account not only economic or technical aspects, but also sociological, political, and environmental criteria. Finally, the developed methodology is applied to a case concrete as example of its potential. An isolated community in the Democratic Republic of the Congo has been selected since 90% of the population living in areas isolated from the mains, and being one of the African countries with the greatest potential for renewable energy generation. / El objetivo de esta tesis es la definición y desarrollo de una metodología integral de planificación energética para zonas aisladas de la red eléctrica que considere no solo el contexto energético del país y su desarrollo hacia un escenario sostenible, sino también el estudio del potencial de generación renovable en la zona remota a estudiar, la capacidad de gestión de la demanda y los aspectos socio-económicos que intervienen en la decisión final sobre qué solución energética renovable sería la más apropiada de acuerdo con las características de la ubicación. El trabajo de investigación se organiza en tres grandes etapas. La primera donde se define el algoritmo de análisis del contexto energético del país y su evolución hacia un escenario energético futuro basado en energías renovables. Una segunda fase donde se analizan las mejores configuraciones de sistemas renovables híbridos capaces de responder a las necesidades energéticas de la zona, clasificándolas en base a su valor neto actual. Y una tercera donde se describe el método de análisis multi-criterio que permite seleccionar, de entre todas las posibles configuraciones identificadas en la etapa anterior, la más adecuada para las necesidades y características de la zona a estudiar, teniendo en cuenta no solo aspectos económicos o técnicos, sino también criterios sociológicos, políticos y medioambientales. Finalmente, se aplica la metodología a un caso concreto en la República Democrática del Congo como ejemplo de su aplicación. Para el análisis del caso de estudio, se ha seleccionado una comunidad aislada en la República Democrática del Congo ya que el 90% de la población vive en zonas aisladas de la red eléctrica, y es uno de los países de África con mayor potencial de generación con energías renovables. / L'objectiu d'aquesta tesi és la definició i desenvolupament d'una metodologia integral de planificació energètica per a zones aïllades de la xarxa elèctrica que considere no solament el context energètic del país i el seu desenvolupament cap a un escenari sostenible, sinó també l'estudi del potencial de generació renovable en la zona remota a estudiar, la capacitat de gestió de la demanda i els aspectes soci-econòmics que intervenen en la decisió final sobre quina solució energètica renovable seria la més apropiada d'acord amb les característiques de la ubicació. El treball de recerca s'organitza en tres grans etapes. La primera on es defineix l'algorisme d'anàlisi del context energètic del país i la seua evolució cap a un escenari energètic futur basat en energies renovables. Una segona fase on s'analitzen les millors configuracions de sistemes renovables híbrids capaços de respondre a les necessitats energètiques de la zona, classificant-les sobre la base del seu valor net actual. I una tercera on es descriu el mètode d'anàlisi multi-criteri que permet seleccionar, d'entre totes les possibles configuracions identificades en l'etapa anterior, la més adequada per a les necessitats i característiques de la zona a estudiar, tenint en compte no sol aspectes econòmics o tècnics, sinó també criteris sociològics, polítics i mediambientals. Finalment, s'aplica la metodologia a un cas concret en la República Democràtica del Congo com a exemple de la seua aplicació. Per a l'anàlisi del cas d'estudi, s'ha seleccionat una comunitat aïllada en la República Democràtica del Congo ja que el 90% de la població viu en zones aïllades de la xarxa elèctrica, i és un dels països d'Àfrica amb major potencial de generació amb energies renovable. / Peñalvo López, E. (2017). Metodología de Evaluación y Optimización de Sistemas Renovables Híbridos para Electrificación de Zonas Aisladas de la Red [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/82308 / TESIS

Le projet Smart Thermogène Grid® s’intègre dans la dynamique actuelle d’économie d’énergie en s’intéressant à la mise en œuvre de solutions de récupération et de stockage des énergies fatales et renouvelables dans le bâtiment résidentiel. L’objectif de ce travail de thèse est de proposer une approche globale permettant le choix et le dimensionnement de ces systèmes. Ce manque freine leur intégration au sein du bâtiment ainsi que l’évolution du bilan énergétique. Dans ce contexte, une modélisation de type « boites grises » qui se base sur un assemblage de modules (récupérations sur air extrait, sur eaux usées et solaire, stockages géothermique et en cuve) a été développée. Ce type de démarche permet une simplification importante du modèle complet et une réduction considérable du nombre de paramètres à déterminer. Il devient alors possible de mettre en place une méthode d’optimisation sous contrainte de type GPS afin d’aboutir à un dimensionnement physique. Une solution discrète est ensuite proposée grâce à une recherche dans des bases de données. Il est ainsi possible de répondre à la problématique et de proposer un dimensionnement cohérent du SThG®. / The goal of the SThG® project is to recycle, to store and to manage unavoidable and renewable energies in the residential building. The aim of the work performed is to fill the lack of research on global sizing of systems, which is a barrier to the evolution of the energy balance of the building. Indeed, available tools are not adapted to make optimized choices and to size systems as they are very time-consuming. That is why an alternative model has been found. This work can be divided into two main steps. The first one, consists in doing a simplified model of a building and its systems. The second one in applying optimization to have the best choice and the better sizing of those systems according to energy and economic criterions. To solve this problem a model has been developed and two blocks can be identified. The first block is composed of two main points: the establishment of a physical model and the physical optimization. First, a macroscopic model of a building and its systems (recovery, storage and generation) has been created. This model is as much as generic as possible in order to represent a huge part of systems. But, it is also precise to ensure a good description of the real way they work and to allow the link to systems after the physical optimization during block two. Secondly, a Global Pattern Search optimization is used to find the best physical solution according to the constraints of the situation. The second block permits to find solutions in a discrete data basis of systems. These two blocks allow a durability of the tool, indeed the mechanism of optimization depends on the physical model. It will be possible to enrich the data basis of the second block without reconsidering the first one. Thanks to this work, a consistent choice and sizing of systems can be found.

Chemical energy plays a big role in the process of modern Electric Arc Furnace (EAF). The objective of this study is to compare the results of chemical reaction enthalpies calculated by four different methods. In general, the “PERRY-NIST-JANAF method” is used to calculate the chemical energies. However, this method heavily depend on heat capacities of the substances which have to be deduced from  “Perry’s Chemical Engineers’ Handbook” and “NIST-JANAF Thermochemical Tables”, even the calculation process is complicated. Then, some other methods are introduced: Total enthalpy method, HT (High Temperature) enthalpy method and Atomic energy method. In this thesis, the above four methods have been used to calculate the enthalpies of chemical reactions in EAF process. Both of “Total enthalpy method” and “HT enthalpy method” are not complicated, but some basic data are not available. The calculation for chemical reaction enthalpies cannot be completely made by these two methods. “Atomic energy method” is more complicated than “Total enthalpy method” and “HT enthalpy method”, even almost all data are available, but some results of these methods are far from those of the other three methods’. The results show that values of enthalpies obtained by “PERRY-NIST-JANAF method” are more reasonable, though the calculation process is more complicated. In this study, it is also discussed two influencing factors on EAF process: electric power and electromagnetic stirring (EMS).

Brazil started the Luz Para Todos (Light for all - LPT) program in 2003 aiming at universalization of electricity access in the country. The program uses three technological solutions to reach this goal: grid extension, decentralized power generation with isolated grids and stand-alone systems. This master thesis analyzes the role of decentralized renewable energy technologies in the Luz Para Todos program in the state of Minas Gerais. The factors that lead to the use of such technologies in the specific case of CEMIG (Energy Company of Minas Gerais) are considered. The study showed that regulatory framework and energy policy mechanisms are the most important determinants of the method of attendance in rural electrification. It is concluded that decentralized renewable energy technologies emerge as a strong alternative when it is not technologically and/or financially feasible to extend the grid.

Energy generation and use is one of the main contributors to climate change, as it is responsible for two thirds of the global greenhouse gas emissions (IEA 2015). In this context, renewable energies (RE) are increasingly gaining momentum as a key driver for the transition towards a low-carbon society (REN21 2016) and a source of technological and social innovation. The deployment of RE and its integration in large-scale power generation systems has been progressively driven by supportive policy frameworks adopted by pioneering countries such as Germany, Spain and France. This has subsequently fostered a process of learning and spreading of policies between leading countries and other governments willing to implement RE support schemes. Within the field of comparative public policy, different but interrelated approaches of the phenomenon of policy spreading have been developed, among which the most rehearsed are policy diffusion, policy transfer, policy convergence and lesson-drawing. The present study addresses a specific case of policy transfer between Germany-Spain and Peru for the implementation in the latter of a policy framework to foster the development of RE technologies (Legislative Decree 1002) in 2008, and the subsequent adoption of a support policy mechanism, Renewable Auctions (RA) in 2009. The assessment of the policy transfer process has been carried out by applying the Dolowitz and Marsh Model (Dolowitz and Marsh 1996, 2000). Furthermore, an exploratory analysis of the impacts of the policy transfer process in the development of the Peruvian Solar PV technology innovation system has been conducted in order to assess the outcomes of the policy transfer process in terms of RE technological deployment in the country, tackling Solar PV as the RE technology in focus. For this purpose, a simplified adaptation of the technology innovation system framework (TIS) developed by Hekkert et al. 2007 and Bergek et al 2008 has been employed. The results of the study show that the transfer of knowledge related to RE policy-making involved both voluntary and coercive causes. The drivers for the occurrence of policy transfer were the pressure exerted by a foreigner actor (US) for the enforcement of the RE policy framework (LD 1002) in Peru and the institutional support provided by a “convinced bureaucrat” (the former Vice Minister of Energy). The choice of adopting RA instead of other instruments such as  Feed-in-tariffs or Feed-in-premiums is related to the know-how of the country in terms of infrastructure investments and its traditional “modus-operandi”, the availability of natural and financial resources within the country, the perception of technical and financial risks, the negative lessons drawn from the experiences of Spain and Germany regarding the implementation of FITs, and the current state of development of the global RE sector. The policy transfer process has contributed to the development of some components of the Peruvian Solar PV innovation system. From a structural point of view, it has triggered a diversification of the actors involved, mainly driven by the incorporation of large foreign companies specialized in RE, as well as conventional energy companies that have diversified their core activities towards RE. From a dynamic perspective, the implementation of RA has promoted the increase in Solar PV installed capacity and its contribution to the electricity mix, promoting chiefly the function of market formation.

No description available.

yes / The non-isothermal kinetic and thermal behaviour of a naturally formed dolomite in conditions that approach in situ CO2 capture in chemical looping reforming, were investigated. The performance of this dolomite was studied at micro-scale in ‘dry’ conditions, as well as at macro-scale in ‘dry’ and ‘wet’ conditions to investigate the effects of scale (3 mg, 2.5 g), partial pressures of CO2 (<15 kPa) and steam, and deactivation upon limited cycling. The carbonation and calcination kinetics were modelled using an improved iterative Coats–Redfern method. Increasing CO2 partial pressures on the ‘dry’ macroscale exacerbated the experimental carbonation conversions in an inversely proportional trend when compared with those at micro-scale. The presence of steam had a positive effect on CO2 chemisorption. Steam had a negligible influence on the calcination activation energies. The activation energies of carbonation were increased for the experiments at the highest CO2 partial pressures under wet conditions.

No / Transmembrane pore formation is central to many biological processes such as ion transport, cell fusion, and viral infection. Furthermore, pore formation in the ceramide bilayers of the stratum corneum may be an important mechanism by which penetration enhancers such as dimethylsulfoxide (DMSO) weaken the barrier function of the skin. We have used the potential of mean constraint force (PMCF) method to calculate the free energy of pore formation in ceramide bilayers in both the innate gel phase and in the DMSO-induced fluidized state. Our simulations show that the fluid phase bilayers form archetypal water-filled hydrophilic pores similar to those observed in phospholipid bilayers. In contrast, the rigid gel-phase bilayers develop hydrophobic pores. At the relatively small pore diameters studied here, the hydrophobic pores are empty rather than filled with bulk water, suggesting that they do not compromise the barrier function of ceramide membranes. A phenomenological analysis suggests that these vapor pores are stable, below a critical radius, because the penalty of creating water-vapor and tail-vapor interfaces is lower than that of directly exposing the strongly hydrophobic tails to water. The PMCF free energy profile of the vapor pore supports this analysis. The simulations indicate that high DMSO concentrations drastically impair the barrier function of the skin by strongly reducing the free energy required for pore opening. / EPSRC