One of the key steps of the liberalization of the Turkish electricity market has been the estab- lishment of PMUM (Turkish day ahead electricity market). The aim of this study is to explore the dynamics of electricity prices observed in this market and their relation with temperature observed in Turkey. The electricity price process is studied as a univariate process and the same process is studied along with temperature together as a two-dimensional process. We give a fairly complete model of temperature. We observe that the electricity prices in Turkey exhibit many of the features that similar prices exhibit in other world markets. In particular, Turkish day ahead prices are seasonal / every year the price seems to follow a path similar to the one years preceding it. To simplify our analysis we focus our study to a 35 day pe- riod where every year the prices show a relatively simple behavior. We study the effects of the fluctuations in temperature in this period on the fluctutations in the day ahead electricity price.

[pt] A possível mudança no paradigma de formação de preço no Brasil do modelo vigente por custos auditados para o modelo por oferta, com o objetivo de modernizar o Setor Elétrico e buscar práticas que incentivem a competição, implica a necessidade de estudos prévios para auxiliar o processo de transição e a definição do desenho de mercado adequado à realidade brasileira. Nesse sentido, o uso de modelos de equilíbrio, notadamente o Equilíbrio de Nash, desponta como uma poderosa ferramenta ex-ante que permite analisar o comportamento dos competidores para identificar possíveis ineficiências a serem mitigadas. Com esse fim, o presente trabalho modela o processo decisório de ofertas ótimas de um competidor em um mercado de energia elétrica de dia-seguinte de base hidrotérmica por um modelo de otimização binível, possibilitando a identificação do Equilíbrio de Nash do mercado através de um algoritmo baseado em Gauss-Seidel. Adicionalmente, o método é aplicado a dois experimentos numéricos: a um sistema-teste de três barras e a um caso representativo do sistema brasileiro completo, permitindo a análise do comportamento dos competidores a partir da comparação dos resultados com os modelos de Custos Auditados e Equilíbrio Competitivo. Foram observados os impactos das afluências e das cascatas de usinas hidrelétricas de múltiplos proprietários nas receitas e, consequentemente, no comportamento dos competidores. Por fim, foi verificada a ocorrência de competição exclusivamente pelas quantidades, além da prática de retenção de ofertas por parte dos competidores para a modificação do preço de equilíbrio de mercado, aumentando suas receitas. / [en] The potential shift in Brazil s energy pricing paradigm from the current Audited Costs model to the Bid-Bases model, with the aim of modernizing the electricity sector and seeking practices that encourage competition, implies the need for preliminary studies to assist the transition process and define the appropriate market design for the Brazilian reality. In this sense, the use of equilibrium models, notably the Nash Equilibrium, emerges as a powerful ex-ante tool that allows the analysis of competitors behavior to identify possible inefficiencies to be mitigated.To this end, this thesis models the optimal bidding decision process of a competitor in a hydrothermal day-ahead electricity market using a bilevel optimization model, enabling the identification of the Nash Equilibrium of the market through an algorithm based on the Gauss-Seidel. Additionally, the method is applied to two numerical experiments: a three-bus test system and a representative case of the complete Brazilian system, allowing for the analysis of competitors behavior by comparing the results with the Audited Costsand Competitive Equilibrium models. The impacts of water inflows and hydro plants in cascade with distinct ownership on revenues and consequently competitors behavior were observed. Finally, the occurrence of competition exclusively in quantities was verified, as well as the practice of quantity bids retention by competitors in order to modify the market equilibrium price, increasing their revenues.