Power producers trading electricity in both pool and forward markets

The electricity industry throughout the world, which has long been dominated by vertically integrated utilities, has experienced major changes. Deregulation, unbundling, wholesale and retail wheeling, and real-time pricing were abstract concepts a few years ago. Today market forces drive the price of electricity and reduce the net cost through increased competition. As power markets continue to evolve, there is a growing need for advanced modeling approaches. This article addresses the challenge of maximizing the profit (or return) of power producers through the optimization of their share of customers. Power producers have fixed production marginal costs and decide the quantity of energy to sell in both day-ahead markets and a set of target clients, by negotiating bilateral contracts involving a three-rate tariff. Producers sell energy by considering the prices of a reference week and five different types of clients with specific load profiles. They analyze several tariffs and determine the best share of customers, i.e., the share that maximizes profit. © 2014 IEEE.

Spinning reserve and emission unit commitment through stochastic optimization

This paper proposes a stochastic mixed-integer linear approach to deal with a short-term unit commitment problem with uncertainty on a deregulated electricity market that includes day-ahead bidding and bilateral contracts. The proposed approach considers the typically operation constraints on the thermal units and a spinning reserve. The uncertainty is due to the electricity prices, which are modeled by a scenario set, allowing an acceptable computation. Moreover, emission allowances are considered in a manner to allow for the consideration of environmental constraints. A case study to illustrate the usefulness of the proposed approach is presented and an assessment of the cost for the spinning reserve is obtained by a comparison between the situation with and without spinning reserve.

Commercial agentes portfolio optimization in electricity markets

As it is well known, competitive electricity markets require new computing tools for power companies that operate in retail markets in order to enhance the management of its energy resources. During the last years there has been an increase of the renewable penetration into the micro-generation which begins to co-exist with the other existing power generation, giving rise to a new type of consumers. This paper develops a methodology to be applied to the management of the all the aggregators. The aggregator establishes bilateral contracts with its clients where the energy purchased and selling conditions are negotiated not only in terms of prices but also for other conditions that allow more flexibility in the way generation and consumption is addressed. The aggregator agent needs a tool to support the decision making in order to compose and select its customers' portfolio in an optimal way, for a given level of profitability and risk.

Self-scheduling and bidding strategies of thermal units with stochastic emission constraints

This paper is on the self-scheduling problem for a thermal power producer taking part in a pool-based electricity market as a price-taker, having bilateral contracts and emission-constrained. An approach based on stochastic mixed-integer linear programming approach is proposed for solving the self-scheduling problem. Uncertainty regarding electricity price is considered through a set of scenarios computed by simulation and scenario-reduction. Thermal units are modelled by variable costs, start-up costs and technical operating constraints, such as: forbidden operating zones, ramp up/down limits and minimum up/down time limits. A requirement on emission allowances to mitigate carbon footprint is modelled by a stochastic constraint. Supply functions for different emission allowance levels are accessed in order to establish the optimal bidding strategy. A case study is presented to illustrate the usefulness and the proficiency of the proposed approach in supporting biding strategies. (C) 2014 Elsevier Ltd. All rights reserved.

Vakioidut optiot sähkökaupassa

Pohjoismaiset sähkömarkkinat ovat muuttuneet viime vuosina huomattavasti. Sähkömarkkinalakiuudistuksessa poistettiin muodollisesti kilpailun esteet, mutta uusien toimintamuotojen omaksuminen on Suomessa vasta alussa. Sähkömarkkinaosapuolet altistuvat riskriskeille, joita toimialalla ei ole aikaisemmin esiintynyt. Suurimpana riskitekijänä voidaan pitää epävarmuutta tulevasta sähkön hintatasosta, joka voi vaikuttaa merkittävästi yrityksen liiketoiminnan tulokseen. Tässä diplomityössä tarkastellaan, miten hinnanvaihtelua vastaan pystytään suojautumaan sähköjohdannaisten avulla. Kaupankäynti johdannaissopimuksilla edellyttää markkinoiden aktiivista seuraamista ja organisoitua sähkökaupan riskienhallintaa. Riskienhallinnan tehtävänä ei ole riskien eliminoiminen, vaan niiden sopeuttaminen yrityksen tuotto-odotuksien ja riskiensietokyvyn mukaisiksi. Ennen sähkömarkkinoiden avautumista suojauduttiin sähkön hintariskeiltä pitkillä toimitussopimuksilla. Uudessa markkinatilanteessa suojaus voidaan toteuttaa joustavasti ja kohtuullisin kustannuksin käyttämällä johdannaissopimuksia, joilla voidaan poistaa tulevaisuuteen kohdistuvaa epävarmuutta sähkönhinnasta. Pohjoismaisessa sähköpörssissä, Nord Pool ASA:ssa, noteerattavat johdannaiset ovat vakioituja. Lokakuun lopussa 1999 kaupankäynnin kohteeksi otetaan termiinien lisäksi myös vakioidut sähköoptiot. Option ostajalle avautuu mahdollisuus hintasuojaukseen instrumenteilla, joita käyttäen suojaustaso voidaan määrittää etukäteen. Vakioitujen sähköoptioiden mukaan ottaminen sähköpörssin tuotevalikoimaan monipuolistaa huomattavasti ostajien ja myyjien suojautumismahdollisuuksia. Suojaustasoa on tarpeen vaatiessa mahdollista muuttaa vastamaan uutta markkinatilannetta. Työn loppuosassa on tutkittu mahdollisia kaupankäyntistrategioita ja hinnoittelumalleja sähköoptioille. Koska tutkimus on tehty ennen pörssissä tapahtuvan optiokaupan alkamista, useisiin tässä työssä avoimiksi jääneisiin kysymyksiin tullaan saaman vastauksia käytännön kokemuksista.

Relações Brasil-Angola no pós-guerra fria : os condicionantes internos e a via multilateral

Este estudo apresenta reflexões a respeito das relações Brasil-Angola no período compreendido entre os anos de 1990 e 2002. Tendo como ponto de partida o estabelecimento (e aprofundamento) das relações bilaterais no período entre os anos de 1975 e 1990, o presente estudo fornece subsídios que orientam o teor do contato Brasília-Luanda no período pós-Guerra Fria. Entre esses subsídios encontram-se os condicionantes internos, que em cada país influíram de modo determinante na sua respectiva atuação externa, aliados ao contexto de reestruturação internacional. Assim, pela relevância da adaptação por que passaram esses contatos bilaterais, o trabalho distingue essas relações entre diretas e indiretas, estas últimas efetivadas pela via multilateral, seja no cenário regional (notadamente na implantação da CPLP e possibilidade de concretização da ZOPACAS), seja no cenário internacional, com a atuação conjunta nas Nações Unidas.

O tratamento dos contratos de locação comercial de devedor locatário em recuperação judicial: uma análise à luz das tensões entre o direito material e concursal

Este estudo tem o objetivo de verificar o tratamento dado aos contratos de Locação Comercial de Devedor Locatário em Recuperação Judicial. A lei 11.101/2005 determina, em seus artigos 117 e 119,VII, que os contratos bilaterais não se resolvem pela falência e que na falência do locatário, o administrador judicial pode, a qualquer tempo, denunciar o contrato. Porém, a lei é lacônica a respeito do processo de Recuperação Judicial. Então, o estudo pretende verificar a aplicabilidade dos artigos pertinentes à falência, aos contratos de Devedor submetido ao processo de Recuperação Judicial. Com o intuito de realizar interpretação congruente com a eficiência que se espera da legislação em comento, a metodologia utilizada no trabalho é a da Análise Econômica do Direito, segundo os contornos conferidos pelo autor THOMAS H. JACKSON. Assim, o trabalho aproveita os conceitos do common pool assets e dos executory contracts para auxiliar na compreensão da função dos contratos de locação no Processo de Recuperação Judicial. Nesse sentido, o estudo é importante, pois estabelece parâmetros de interpretação teleológica da legislação concursal, considerando-se as tensões entre o Direito Material e Concursal aplicáveis a hipótese aqui formulada. Então, constatou-se que o tema gera divergência de entendimentos perante a jurisprudência brasileira, no que se refere a possibilidade, ou não, de despejar locatário Devedor em Recuperação Judicial. A controvérsia ronda, principalmente, em torno de duas questões: (a) a aplicação do principio da preservação da empresa, presente no art. 47. da L.11.101/2005 (b) (i)liquidez da ação de despejo por falta de pagamento para fins do artigo 6 da mesma lei. Por fim, o estudo avalia forma pela qual a jurisprudência trata do tema e a sua compatibilidade com a metodologia de Análise Econômica Aplicável ao Direito Concursal.

Modelo AC para el despacho combinado de contratos bilaterales y bolsa de energía considerando restricciones de seguridad

Reliability is a key aspect in power system design and planning. Maintaining a reliable power system is a very important issue for their design and operation. Under the new competitive framework of the electricity sector, power systems find ever more and more strained to operate near their limits. Under this new scenario, it is crucial for the system operator to use tools that facilitate an energy dispatch that minimizes possible power cuts. This paper presents a mathematical model to calculate an energy dispatch that considers security constraints (single contingencies in transmission lines and transformers). The model involves pool markets and fixed bilateral contracts. Traditional methodologies that include security constraints are usually based in multistage dispatch processes. In this case, we propose a single-stage model that avoids the economic inefficiencies which result when conventional multi-stage dispatch approaches are applied. The proposed model includes an AC representation of the transport system and allows calculating the cost overruns incurred in due to reliability restrictions. We found that complying with fixed bilateral contracts, when they go above certain levels, might lead to congestion problems in transmission lines.

Modelo de leilão multiperíodo para sistemas hidrotérmicos com representação da transmissão

Pós-graduação em Engenharia Elétrica - FEB

Previsão multi-passos a frente do preço de energia elétrica de curto prazo no mercado brasileiro

A predição do preço da energia elétrica é uma questão importante para todos os participantes do mercado, para que decidam as estratégias mais adequadas e estabeleçam os contratos bilaterais que maximizem seus lucros e minimizem os seus riscos. O preço da energia tipicamente exibe sazonalidade, alta volatilidade e picos. Além disso, o preço da energia é influenciado por muitos fatores, tais como: demanda de energia, clima e preço de combustíveis. Este trabalho propõe uma nova abordagem híbrida para a predição de preços de energia no mercado de curto prazo. Tal abordagem combina os filtros autorregressivos integrados de médias móveis (ARIMA) e modelos de Redes Neurais (RNA) numa estrutura em cascata e utiliza variáveis explanatórias. Um processo em dois passos é aplicado. Na primeira etapa, as variáveis explanatórias são preditas. Na segunda etapa, os preços de energia são preditos usando os valores futuros das variáveis exploratórias. O modelo proposto considera uma predição de 12 passos (semanas) a frente e é aplicada ao mercado brasileiro, que possui características únicas de comportamento e adota o despacho centralizado baseado em custo. Os resultados mostram uma boa capacidade de predição de picos de preço e uma exatidão satisfatória de acordo com as medidas de erro e testes de perda de cauda quando comparado com técnicas tradicionais. Em caráter complementar, é proposto um modelo classificador composto de árvores de decisão e RNA, com objetivo de explicitar as regras de formação de preços e, em conjunto com o modelo preditor, atuar como uma ferramenta atrativa para mitigar os riscos da comercialização de energia.

Estudo e análise do risco e da viabilidade econômica do mercado cativo e do mercado livre de energia elétrica no terceiro ciclo tarifário

In 2004 two trading environment for contracts of purchase and of electricity energy were established, the Regulated Contracting Environment (RGE) and the Free Contracting Environment (FCE). In the first one, consumers can only buy their energy directly from local electricity distribution, and in the second one, consumers can choose their delivery, amount and type of energy that they will burn through bilateral contracts. Thus, before deciding to migrate to the FCE, it is necessary understanding the rules of marketing, the risk involved and the economic viability of the two markets so can determine which environment has more benefits to the consumer. This paper aims to offer tools to support takeover decision of potentially free costumers, who have the option to migrate to market in order to evaluate the benefits and disadvantages of each market. This paper has also considered the new rules of the third rate cycle, where consumers can opt for green tax. The methodology presented is based on calculations of spending with energy and the risk of flag in captive market and free market in one year

Competition and cost overruns. Optimal misspecification of procurement contracts

Most cases of cost overruns in public procurement are related to important changes in the initial project design. This paper deals with the problem of design specification in public procurement and provides a rationale for design misspecification. We propose a model in which the sponsor decides how much to invest in design specification and awards competitively the project to a contractor. After the project has been awarded the sponsor engages in bilateral renegotiation with the contractor, in order to accommodate changes in the initial project s design that new information makes desirable. When procurement takes place in the presence of horizontally differentiated contractors, the design s specification level is seen to affect the resulting degree of competition. The paper highlights this interaction between market competition and design specification and shows that the sponsor s optimal strategy, when facing an imperfectly competitive market supply, is to underinvest in design specification so as to make significant cost overruns likely. Since no such misspecification occurs in a perfectly competitive market, cost overruns are seen to arise as a consequence of lack of competition in the procurement market.

Contracts, Reference Points, and Competition - Behavioral Effects of the Fundamental Transformation

In this paper we study the role of incomplete ex ante contracts for ex post trade. Previous experimental evidence indicates that a contract provides a reference point for entitlements when the terms are negotiated in a competitive market. We show that this finding no longer holds when the terms are determined in a non-competitive way. Our results imply that the presence of a "fundamental transformation" (i.e., the transition from a competitive market to a bilateral relationship) is important for a contract to become a reference point. To the best of our knowledge this behavioral aspect of the fundamental transformation has not been shown before.

Bilateral Peripheral Facial Palsy And Mastoid Infiltration As Symptoms Of Relapsed Acute Myeloid Leukemia.

Although Bell's palsy (BP) is the most common cause of peripheral facial palsy (PFP), other etiologies merit investigation. A 60-year-old female patient presented with recurrent bilateral PFP. Although the patient had a history of acute myeloid leukemia (AML), she had initially been diagnosed with BP-related PFP and had been treated accordingly. When the PFP recurred, additional diagnostic tests were performed. The resulting immunohistochemical profile included CD3 positivity in a few reactive T lymphocytes; positivity for myeloperoxidase in atypical cells; and focal positivity for CD34 and proto-oncogene c-kit proteins in neoplastic cells, thus confirming the suspicion of mastoid infiltration caused by relapsed AML. In patients with neoplastic disease, a finding of PFP calls for extensive investigation in order to rule out the involvement of the temporal bone.

Preservation Of The External Jugular Vein In Bilateral Radical Neck Dissections: Technique In Two Cases And Review Of The Literature.

Context. The possibility of cephalic venous hypertension with the resultant facial edema and elevated cerebrospinal fluid pressure continues to challenge head and neck surgeons who perform bilateral radical neck dissections during simultaneous or staged procedures. Case Report. The staged procedure in patients who require bilateral neck dissections allows collateral venous drainage to develop, mainly through the internal and external vertebral plexuses, thereby minimizing the risks of deleterious consequences. Nevertheless, this procedure has disadvantages, such as a delay in definitive therapy, the need for a second hospitalization and anesthesia, and the risk of cutting lymphatic vessels and spreading viable cancer cells. In this paper, we discuss the rationale and feasibility of preserving the external jugular vein. Considering the limited number of similar reports in the literature, two cases in which this procedure was accomplished are described. The relevant anatomy and technique are reviewed and the patients' outcomes are discussed. Conclusion. Preservation of the EJV during bilateral neck dissections is technically feasible, fast, and safe, with clinically and radiologically demonstrated patency.