The use of electricity in 21st century living has been firmly established throughout most of the world, correspondingly the infrastructure for production and delivery of electricity to consumers has matured and stabilised. However, due to recent technical and environmental–political developments, the electricity infrastructure worldwide is undergoing major restructuring. The forces driving this reorganisation are a complex interplay of technical, environmental, economic and political factors. The general trend of the reorganisation is a dis–aggregation of the previously integrated functions of generation, transmission and distribution, together with the establishment of competitive markets, primarily in generation, to replace previous regulated monopolistic utilities. To ensure reliable and cost effective electricity supply to consumers it is necessary to have an accurate picture of the expected generation in terms of the spatial and temporal distribution of prices and volumes. Previously this information was obtained by the regulated utility using technical studies such as centrally planned unit–commitment and economic–dispatch. However, in the new deregulated market environment such studies have diminished applicability and limited accuracy since generation assets are generally autonomous and subject to market forces. With generation outcomes governed by market mechanisms, to have an accurate picture of expected generation in the new electricity supply industry, it is necessary to complement traditional studies with new studies of market equilibrium and stability. Models and solution methods have been developed and refined for many markets, however they cannot be directly applied to the generation market due to the unique nature of electricity, having high inelastic demand, low storage capability and distinct transportation requirements. Intensive effort is underway to formulate solutions and models that specifically reflect the unique characteristics of the generation market. Various models have been proposed including game theory, stochastic and agent–based systems. Similarly there is a diverse range of solution methods including, Monte–Carlo simulations, linear–complimentary and quadratic programming. These approaches have varying degrees of generality, robustness and accuracy, some being better in certain aspects but weaker in others. This thesis formulates a new general model for the generation market based on the Cournot game, it makes no conjectures about producers’ behaviour and assumes that all electricity produced is immediately consumed. The new formulation characterises producers purely by their cost curves, which is only required to be piece–wise differentiable, and allows consumers’ characteristics to remain unspecified. The formulation can determine dynamic equilibrium and multiple equilibria of markets with single and multiple consumers and producers. Additionally stability concepts for the new market equilibrium is also developed to provide discrimination for dynamic equilibrium and to enable the structural stability of the market to be assessed. Solutions of the new formulation are evaluated by the use of evolutionary computation, which is a guided stochastic search paradigm that mimics the operation of biological evolution to iteratively produce a population of solutions. Evolutionary computation is employed as it is adept at finding multiple solutions for underconstrained systems, such as that of the new market formulation. Various enhancements to significantly improve the performance of the algorithms and simplify its application are developed. The concept of convergence potential of a population is introduced together with a system for the controlled extraction of such potential to accelerate the algorithm’s convergence and improve its accuracy and robustness. A new constraint handling technique for linear constraints that preserves the solution’s diversity is also presented together with a coevolutionary solution method for the multiple consumers and producers market. To illustrate the new electricity market formulation and its evolutionary computation solution methods, the equilibrium and stability of a test market with one consumer and thirteen thermal generators with valve point losses is examined. The case of a multiple consumer market is not simulated, though the formulation and solution methods for this case is included. The market solutions obtained not only confirms previous findings thus validating the new approach, but also includes new results yet to be verified by future studies. Techniques for market designers, regulators and other system planners in utilising the new market solutions are also given. In summary, the market formulation and solution method developed shows great promise in determining expected generation in a deregulated environment.

L’objet de cette thèse est l’intégration des parcs photovoltaïques intelligents au marché de l’électricité dans un environnement de libre concurrence. Les centrales photovoltaïques intelligentes sont celles qu’incluent systèmes de stockage pour réduire sa variabilité et en plus fournir à l’ensemble une plus grande contrôlabilité. Ces objectives techniques sont obtenues grâce à la capacité bidirectionnelle d’échange et stockage d’énergie qu’apportent les systèmes de stockage, dans ce cas, les batteries. Pour obtenir la rentabilité maximale des systèmes de stockage, le dimensionnement doit être optimisé en même temps que la stratégie de gestion avec laquelle le système de stockage est commandé. Dans cette thèse, une fois la technologie de stockage plus adapté à l’application photovoltaïque est sélectionnée, à savoir la technologie de lithium-ion, une participation innovatrice de part des parcs photovoltaïques intelligents dans le marché de l’électricité est proposée qui optimise à la fois le dimensionnement et la stratégie de gestion d’une manière simultanée. Ce processus d'optimisation ainsi que la participation au marché de l'électricité a été appliquée dans un cas d’étude réel, ce qui confirme que cette procédure permet de maximiser la rentabilité économique de ce type de production. / The present PhD deals with the integration of intelligent photovoltaic (IPV) power plants in the electricity markets in an environment subject to free competition. The IPV power plants are those that include energy storage systems to reduce the variability and to provide the entire group a controllability increase. These technical objectives are obtained thanks to the bidirectional exchanging and storing capability that the storage system contributes to, in this case, battery energy storage system (BESS). In order to obtain the maximum profitability of the BESS, the sizing must be optimized together with the control strategy that the BESS will be operated with. In the present PhD, once the most performing battery energy storage technology has been selected, the lithium-ion technology, an innovative IPV power plant electricity market participation process is proposed which optimizes both the sizing and the energy management strategy in the same optimization step. This optimization process together with the electricity market participation has been applied in a real case study, confirming that this procedure permits to maximize the economic profitability of this type of generation.

Cette thèse évalue les interactions entre le système européen d’échange de quotas de CO2 et les marchés de l’électricité sur la période 2005-2012. Elle est réalisée à partir d’instruments économétriques et de modélisation, permettant d’expliquer les évolutions observées des marchés et de dégager des enseignements pour la conduite des politiques futures. L’analyse ex-post de l’introduction d’un prix du carbone sur les marchés électriques en Europe fait apparaître trois types d’interactions : sur la formation des prix de l’électricité ; sur les choix techno-économiques et les émissions de CO2 ; sur la formation des rentes électriques. Les estimations empiriques mettent en évidence que le degré de répercussion du prix du carbone sur les prix de l’électricité n’est généralement pas homogène mais varie selon les périodes et les marchés en fonction d’une combinaison de facteurs. Les impacts du prix du carbone sur le mix technologique et les émissions de CO2 du secteur électrique sont estimés à partir du modèle de simulation ZEPHYR-Elec, qui a pour objet de reproduire l’équilibre de court terme offre-demande d’électricité. Les réductions d’émissions de la production électrique induites par le marché européen des quotas représentent 3% à 5% des émissions contre-factuelles. Depuis 2012, le prix du carbone ne permet plus de compenser le différentiel de prix gaz-charbon en Europe. Les effets distributifs du prix du carbone sur le secteur électrique sont introduits dans le modèle ZEPHYR-Elec à partir d’une représentation analytique de la formation des rentes. Les estimations suggèrent que les profits du secteur électrique sont globalement plus élevés du fait du prix du carbone, y compris en cas d’allocation aux enchères des quotas. / This thesis is an evaluation of the interaction between the European Union Emissions Trading Scheme and electricity markets over the period 2005-2012. It rests on econometric and modelling instruments to both explain the development of markets and draw lessons for the conduct of future policies. The ex-post analysis of the introduction of a carbon price into electricity markets in Europe unveils three types of interactions with: the formation of electricity prices; the technical and economic choices and CO2 emissions; the formation of electricity rents. Empirical estimates show that the degree to which the carbon cost is passed on through electricity prices is generally not homogeneous but rather varies over both time and markets, contingent upon a combination of factors. The impacts of the carbon price on both the technological mix and the CO2 emissions from the power sector are estimated using the simulation model ZEPHYR-Elec, which aims at replicating the short-term equilibrium between electricity supply and demand. Emission reductions in the electricity sector induced by the European carbon market amount to between 3% and 5% of counterfactual emissions. From 2012 on, the carbon price has not been high enough to compensate for the gas-to-coal price differential in Europe. Distributional effects of the carbon price on the electricity sector are introduced into the ZEPHYR-Elec model using an analytical representation of the formation of rents. Estimates suggest that profits made by the electricity sector are generally higher with a carbon price in place, including when allowances are auctioned.

Orientador: Prof. Dr. João Manoel Losada Moreira / Dissertação (mestrado) - Universidade Federal do ABC. Programa de Pós-Graduação em Energia, 2017. / A integração de mercados de eletricidade entre países pode configurar-se em uma alternativa importante para o planejamento energético nacional, como demonstra o que ocorre na União Europeia, América Central e África. Na União Europeia, as regras de comercialização de energia são tais que a Escandinávia pode vender eletricidade na península ibérica ou qualquer outro país participante do mercado integrado. Naquela região, considera-se que a integração do setor elétrico gerou ganhos de eficiência e segurança energética para os países integrantes do mercado integrado. Os processos de integração e sua arquitetura, contudo, podem ser variados. Na América do Sul não há mercados integrados de energia elétrica, mas ocorre comercialização de eletricidade por meio de acordos binacionais específicos. O Paraguai é o maior exportador de eletricidade no continente devido a acordos binacionais específicos com Brasil e Argentina. Este trabalho estuda a integração de mercados de energia elétrica na América do Sul com foco na comercialização de energia elétrica. Estudam-se as barreiras verificadas no processo de integração, possíveis arquiteturas de integração do ponto de vista da constituição de um mercado integrado regional, possíveis arquiteturas que permitam maior ou menor participação do Estado e estudam-se também questões institucionais técnicas e diplomáticas. A metodologia se baseia em modelos de governança com vários agentes e stakeholders. Conclui-se que é necessário um maior ativismo ou liderança do Brasil na região para estimular o processo de interação, estabelecimento de marcos regulatórios consistentes para viabilizar a comercialização de energia elétrica entre países fronteiriços e definição de papeis e responsabilidades institucionais e operacionais. Países fronteiriços poderiam ser considerados extensões dos mercados nacionais e deveriam compatibilizar e harmonizar suas regras de comercialização de energia elétrica. Do ponto de vista do Brasil, por exemplo, países vizinhos atuariam como submercados do sistema elétrico brasileiro e poderiam participar dos nossos mercados livre e regulado de energia elétrica. / The integration of electricity markets between countries can be an important alternative to national energy planning, as demonstrated in the European Union, Central America and Africa. In the European Union, the electricity trading rules are such that Scandinavia can sell electricity in the Iberian Peninsula or any other country participating in the integrated market. In that region, it is considered that the integrated market produced efficiency gains and energy security for all participating countries. There are various processes of integration and architectures for integrated electricity markets. In South America there is only commercialization of electricity through specific binational treaties. Paraguay is the largest exporter of electricity through specific binational treaties with Brazil and Argentina. This work we study the integration of electric energy markets in South America focused on energy commercialization. We discuss the barriers against the integration process, possible integration architectures from the point of view of the formation a regional electricity market, possible architectures that allow more or less participation of the State, and also study technical and diplomatic institutional issues. The methodology is based on multi-agent and stakeholders governance models. We conclude that there is a need for greater activism or leadership of Brazil in the region to stimulate the integration process, need to establish consistent regulatory frameworks to enable the commercialization of electricity between border countries, need to define institutional and operational roles and responsibilities. Border countries could be considered extensions of the national markets and have their trading rules and other regulations made compatible. From Brazil's point of view, for example, neighboring countries would act as sub-markets of the Brazilian electricity system to participate in our free and regulated electricity markets.

[pt] A dissertação é composta por 3 ensaios nos quais analisam-se os efeitos econômicos da liberalização e regulação de sistemas hidrotérmicos. No primeiro ensaio, um dos principais problemas de mercados de eletricidade liberalizados é tratado: o poder de mercado dos geradores. Analisa-se a eficácia de 2 medidas comumente propostas para sistemas com predominância de termelétricas (incentivos a contratação de longo prazo e redução da concentraçãao horizontal) em um sistema hidrotérmico e mostra-se que diferentes resultados podem ser obtidos. No segundo ensaio, consideram-se os incentivos ao investimento em capacidade de geração no sistema hidrelétrico brasileiro. A entrada futura de capacidade é uma das principais variáveis no despacho centralizado. Quando o investimento é privado, a entrada efetiva de nova capacidade pode ser consideravelmente diferente daquela utilizada no despacho ótimo. Modelos anteriores de opções reais incorporam a decisão estratégica dos investidores em seus modelos, porém não consideram que essa decisão acaba afetando o armazenamento ótimo de água nas hidrelétricas. Essa variável, por sua vez, é fundamental na determinação da evolução da rentabilidade futura de novos projetos o que acaba afetando novamente a decisão de investimento. No terceiro ensaio, discutem-se as experiências de reestruturação dos mercados de eletricidade do Brasil e da Califórnia. Apesar de diferentes objetivos e diferentes estruturas iniciais de mercado, ambos empreenderam a reforma dos seus respectivos setores elétricos baseados amplamente no mesmo modelo de separação vertical em voga nos anos noventa. Coincidentemente, alguns anos depois, ambos enfrentavam sérias crises. Desconsideração de aspectos relevantes na liberalização de mercados e incentivos de regulação inadequados podem ter exacerbado ao invés de atenuado os efeitos deletérios da crise tanto no Brasil quanto na Califórnia. A principal lição das duas experiências reside no reconhecimento de que a liberalização dos mercados elétricos deve ser feita com muito cuidado e com especial atenção ao efeito da nova estrutura na alocação de equilíbrio durante situações extremas de mercado. / [en] This dissertation is structured into 3 essays in which I analyze the economic effects of regulation and liberalization of hydrothermal systems. So far empirical and theoretical studies about power markets have been done mainly for thermal systems, in which equilibrium conditions reflect the fact that current production decisions can be analyzed separately from future production decisions. In hydrothermal systems, however, strategies are dynamically connected what yields equilibrium conditions different from thermal systems. This difference in the nature of the equilibrium is the main building block upon which I will analyze some important questions like liberalization of the market, investment, market power of generators and policies towards its mitigation and to compare the effectiveness of some common proposed policy interventions recommended to thermal systems in the context of a hydrothermal system. In the first essay, I analyze one of the main concerns in restructured electricity markets: the market power of generators. I show that two common mitigation measures proposed for thermal power markets (incentives to long- term contracting and horizontal deconcentration) do not necessarily affect the firms` market power in hydrothermal systems in the same way as in thermal systems. In the second essay, I consider the incentives to investment in the Brazilian centralized dispatch in which future entry of new capacity is one of the most important determinants in the optimal management of the system. When investment is not determinative, investors can choose the most appropriate time to enter into the market. Previous real option models incorporates this flexibility on the optimal time to invest but do not consider that each potential new firm may affect the current optimal stock of water to be left to the next period. The fact that indicative entry plan does not take into account that investors` choice of the optimal time to invest may affect current values (especially the stock of water to be left to the next period)and hence reinforcing possible distortions in the investment decision, given future prices and dispatched quantities depend on the current optimal dispatch. In the third essay, I discuss the restructuring experiences of Brazil and California. Despite different goals and different initial market structures, both undertook the restructuring of their respective electricity sectors largely based on the same deregulation framework in vogue in the 1990s. Coincidently, a few years later, both were facing serious crisis in their respective electricity sectors. The lack of attention to some important aspects of the liberalization or deregulation of the electricity sector and inadequate regulatory incentives could have exacerbated rather than attenuated the deleterious effects of their respective crisis. The main lesson from both experiences is that liberalization or deregulation of electricity markets should be carefully implemented, with special attention to the potential impact of the new structure on the equilibrium allocation during market stress situations.

Les marchés électriques libéralisés sont supposés assurer la coordination de long terme des investissements afin de garantir sécurité d’approvisionnement, viabilité et compétitivité. Dans le modèle de référence energy-only, la formation des prix par alignement sur le coût variable de l’équipement marginal sur les marchés horaires successifs fournit un signal prix pour les investisseurs. Cependant, en pratique, ce modèle est remis en question quant à sa capacité à déclencher des investissements dans les technologies bas-carbone et en particulier les énergies renouvelables (EnR) et quant à sa capacité à garantir la sécurité d’approvisionnement. Cette thèse cherche d’abord à caractériser ces deux défaillances de marché puis s’intéresse à différentes solutions pour faire face à chacune d’entre elles. Pour cela, la réflexion s’appuie sur un modèle en System Dynamics développé afin de simuler les investissements dans les marchés électriques.D’une part, les résultats montrent que le remplacement des mécanismes de support hors marché par des investissements par le marché avec l’aide d’un prix du carbone apparait comme une solution pour déclencher le développement des EnR à condition d'un engagement politique fort en faveur d’un prix du carbone élevé. D’autre part, il apparait aussi que le marché energy-only avec des prix plafonnés ne parvient pas à assurer l’adéquation de capacité. L’ajout d’un marché de capacité ou la suppression du plafond de prix permettent une amélioration en termes de nombre d’heure de délestage et de bien-être collectif. De plus, le marché de capacité apparaît comme le meilleur choix pour le régulateur parmi les architectures de marché considérées. / In liberalised electricity systems, power markets are expected to ensure the long-term coordination of investments in order to guarantee security of supply, sustainability and competitiveness. In the reference energy-only market, it relies on the ability of power markets — where the hourly price is aligned with the marginal cost of the system — to provide an adequate price-signal for investors. However, in practice, questions have been raised about its ability to trigger investments in low-carbon technologies including in particular Renewable Energy Sources of Electricity (RES-E), and its ability to ensure capacity adequacy. After a characterisation of these market failures, this dissertation tackles the two research topics within a methodological framework based on a System Dynamics model developed to simulate private investment decisions in power markets.First, the results show that substituting out-of-market support mechanisms for RES-E by market-based investments helped by the sole implementation of a carbon price appears as a feasible solution to trigger RES-E development providing that there is a political commitment on a high carbon price. Second, it also appears that the energy-only market with price cap is ineffective to ensure capacity adequacy. Adding a capacity market or removing the price cap both bring benefits in terms of loss of load expectation and social welfare. Moreover, the capacity market is identified as the best option for regulators among the considered market designs.

Dans l’industrie électrique, le progrès technologique apporté par les réseaux intelligents vient défier l’idée selon laquelle les consommateurs ne pourraient pas réagir aux prix des marchés de gros. L’intégration des Effacements de Demande (ED) dans le système électrique se heurte néanmoins à la question de leur efficacité économique. Cette thèse évalue la valeur économique des ED en s’appuyant sur un modèle de marché de l’énergie sous incertitude permettant de calculer les profits d’un agrégateur, par classe de consommateur et d’usage final. Le modèle appartient à la classe des problèmes linéaires stochastiques à plusieurs périodes. Sa résolution s’appuie sur Stochastic Dual Dynamic Programming. Il apparaît qu’en France, les secteurs rentables sont le load-shedding industriel et le load-shifting du ciment et du papier. Le load-shifting du chauffage électrique n’est pas profitable pour le tertiaire et le résidentiel. De plus, la valeur capacitaire des ED est déterminante. Dans l’ensemble, les ED deviennent viables mais le développement de leur potentiel semble conditionné à une baisse des coûts fixes dans les technologies de réseau intelligent. / In liberalised power markets the inability of consumers to adapt their demand in accordance to wholesale prices is increasingly challenged. Nowadays technical progress within the smart grid industry constitutes promising changes for the integration of end-users into the power system, but the deployment of Demand Response (DR) still faces the challenge of its economic viability. This thesis aims to assess the economic value of DR. We rely on an energy-only market model under uncertainty in order to quantify the revenues of DR aggregators, classified by category of consumers and end-uses of electricity. The model is formulated as a multi-stage stochastic linear problem and solved by Stochastic Dual Dynamic Programming. It appears that in France, industrial load-shedding and load-shifting of cement, paper, and pulp are profitable. For residential and tertiary consumers, load-shifting of electric heating is not profitable. We also show that the capacity value of DR is crucial. Overall, results show that DR is beginning to become economically attractive, but that fixed costs of smart grid technologies still need to come down further to fully develop its potential.

This dissertation applies a variety of quantitative methods to European electricity market data to enable us to detect, understand, and eventually mitigate market imperfections. The empirical data indicate that market power and barriers to cross-border trade partially explain today’s market failures. Briefly, the five key findings of this dissertation are: First, we observe a decoupling between German electricity prices and fuel cost, even though British electricity prices are largely explained by short-run cost factors. Second, we demonstrate that rising prices of European Union emission allowances (EUA) have a greater impact on German wholesale electricity prices than falling EUA prices. Third, we reject the assumption of full integration of European wholesale electricity markets in 2002-2006; for several pairs of countries, the weaker hypothesis of (bilateral) convergence is accepted (i.e. efforts to develop a single European market for electricity have been only partially successful). Fourth, we observe that daily auction prices of scarce cross-border transmission capacities are insufficient to explain the persistence of international price differentials. Empirically, our findings confirm the insufficiency of explicit capacity auctions as stated in the theoretical literature. Fifth, we identify inefficiencies in the market behavior for the interconnector linking France and the United Kingdom (UK), for which several explanations, including market power, may be plausible.

This report explores the impacts of variable renewable energy (VRE) on power trading in the European wholesale electricity market. The intricate operation of a typical power exchange in Europe is accompanied by an equally complex balancing system. The increasing amount of VRE in the power system, such as wind and solar power, has far-reaching impacts for power traders in both this electricity market and the corresponding balancing system. As a result, the electricity market is evolving in unprecedented ways and new participants are entering the playing field to capitalize on the changing dynamics caused by VRE generators. One novel participant, the virtual power plant (VPP), possesses an advantage over other market participants by aggregating VRE generators with controllable renewable energy generators, like biogas and hydro plants, into one entity. This allows the VPP to both gain access to live VRE production data that larger plants don’t have, which it then utilizes to remotely dispatch various subpools of assets, and to provide balancing services to the grid. Subsequently, VPPs are able to trade VRE and other renewable electricity superiorly on the same spot markets and balancing systems as large central power plants and industrial consumers. The report asserts that VPP traders can earn profits through means of innovative trading strategies that exploit predictable market impacts caused by VRE power through a robust understanding of the electricity market and their unique access to data. / Denna rapport undersöker effekterna av variabel förnybar energi (VRE) på krafthandeln på den europeiska elhandelsmarknaden för stora aktörer. Den komplicerade driften av ett typiskt kraftutbyte i Europa åtföljs av ett lika komplicerat balanseringssystem. Den ökande mängden VRE i kraftsystemet, såsom vind- och solkraft, har långtgående effekter för krafthandlare på både denna elmarknad och motsvarande balanseringssystem. Som ett resultat utvecklas elmarknaden på enastående sätt och nya deltagare kommer in på spelplanen för att dra nytta av den förändrade dynamiken som orsakas av VRE-generatorer. En ny spelare, det virtuella kraftverket (VPP), har en fördel jämfört med andra marknadsaktörer genom att samla VRE-generatorer med styrbara förnybara energiproducenter, som biogas och vattenkraftverk, till en enhet. Detta gör att VPP både kan få tillgång till live VRE-produktionsdata som större anläggningar inte har, som den sedan använder för att distribuera olika underpooler av tillgångar och för att tillhandahålla balanstjänster till nätet. Därefter kan VPP: er handla med VRE och annan förnybar el på ett överlägset sätt på samma spotmarknader och balanseringssystem som stora centrala kraftverk och industrikonsumenter. Rapporten visar att VPP-handlare kan göra vinster genom innovativa handelsstrategier som utnyttjar förutsägbara marknadseffekter orsakade av VRE-kraft genom en detaljerad förståelse för elmarknaden och unik tillgång till data för produktionen av förnybar energi / <p>QC 20201118</p>

Dans cette thèse, nous nous intéressons à des sujets différents en mathématiques financières, tous liés aux imperfections de marché et à la technique fondamentale de la maximisation d'utilité. Elle comporte trois parties. Dans la première, qui se base sur deux papiers, nous considérons le problème d'investissement optimal sur un marché financier avec coûts de transaction proportionnels. On commence par étudier le problème d'investissement dans le cas où la fonction d'utilité est multivariée (ce qui s'adapte particulièrement bien aux marchés des devises) et l'agent a une dotation initiale aléatoire, qui peut s'interpréter comme une option ou un autre contrat dérivé. Après avoir analysé les propriétés du problème et de son dual, nous utilisons ces résultats pour examiner, dans ce contexte, certains aspects d'une technique de pricing devenue populaire dans le cadre des marchés incomplets, l'évaluation par indifférence d'utilité. Dans le deuxième chapitre, nous étudions le problème d'existence d'un ensemble de prix (appelés "prix fictifs" ou "shadow prices") qui offrirait la même utilité maximale à l'agent si le marché n'avait pas de frictions. Ces résultats sont utiles pour clarifier le lien entre la théorie classique des marchés sans frictions et la littérature en croissance rapide sur les coûts de transaction. Dans la deuxième partie de cette thèse, nous considérons le problème d'évaluation de produits dérivés par indifférence d'utilité dans des marchés incomplets, où la source d'incomplétude provient du fait que certains actifs ne peuvent pas être échangés sur le marché, ce qui est le cas par exemple dans le cadre des modèles structurels pour le prix de l'électricité. Sous certaines hypothèses, nous dérivons une caractérisation en terme d'équations différentielles stochastiques rétrogrades (EDSR) pour le prix, et nous nous concentrons ensuite sur les options européennes en établissant en particulier l'existence d'une stratégie de couverture optimale, même lorsque le payoff présente des discontinuités et est éventuellement non borné. Dans la dernière partie, nous analysons un simple problème de principal-agent à horizon fini, où le principal est essentiellement interprété comme un régulateur et l'agent comme une entreprise qui produit certaines émissions polluantes. Nous traitons séparément les problèmes du principal et de l'agent et nous utilisons la théorie des EDSR pour fournir des conditions nécessaires et suffisantes d'optimalité. Nous effectuons également des analyses de sensibilité et nous montrons des résultats numériques dans le but de fournir une meilleure compréhension du comportement des agents. / In this thesis we deal with different topics in financial mathematics, that are all related to market imperfections and to the fundamental technique of utility maximization. The work consists of three parts. In the first one, which is based on two papers, we consider the problem of optimal investment on a financial market with proportional transaction costs. We initially study the investment problem in the case where the utility function is multivariate (which is particularly suitable on currency markets) and the agent is endowed with a random claim, which can be interpreted as an option or another derivative contract. After analyzing the properties of the primal and dual problems, we apply those results to investigate, in this context, some aspects of a popular pricing technique in incomplete markets, i.e. utility indifference evaluation. In the second contribution to the transaction costs literature, we investigate the existence problem for a set of prices (called shadow prices) that would provide the same maximal utility to the agent if the market did not have frictions. These results shed some light on the link between the classical theory of frictionless markets and the quickly growing literature on transaction costs. In the second part of this thesis we consider the utility indifference pricing problem in incomplete markets, where the source of incompleteness comes from the fact that some assets in the market cannot be actively traded, which is the case for example in the framework of structural models for electricity prices. We provide a BSDE characterization for the price under mild assumptions, and then focus on the case of European claims by establishing in particular the existence of an optimal hedging strategy even when the claim presents discontinuities and is possibly unbounded. In the last contribution we analyze a simple principal-agent problem in finite time horizon, where the principal is mainly interpreted as a regulator and the agent as a firm producing some kind of polluting emissions. We separately treat both the agent's and the principal's problems and use the BSDE theory for providing necessary and sufficient conditions for optimality. We also perform some sensitivity analyses and give numerical results in order to provide a better understanding of the agents' behavior.