Alberto L. Francato

Optimization of Large-Scale Hydrothermal System Operation

This paper presents the development of a mathematical model to optimize the management and operation of the Brazilian hydrothermal system. The system consists of a large set of individual hydropower plants and a set of aggregated thermal plants. The energy generated in the system is interconnected by a transmission network so it can be transmitted to centers of consumption throughout the country. The optimization model offered is capable of handling different types of constraints, such as interbasin water transfers, water supply for various purposes, and environmental requirements. Its overall objective is to produce energy to meet the country’s demand at a minimum cost. Called HIDROTERM, the model integrates a database with basic hydrological and technical information to run the optimization model, and provides an interface to manage the input and output data. The optimization model uses the General Algebraic Modeling System (GAMS) package and can invoke different linear as well as nonlinear programming ...

Daily reservoir inflow forecasting using fuzzy inference systems

This paper presents the application of a methodology for daily reservoir inflow forecasting in Brazilian hydroelectric plants. The methodology is based on Fuzzy Inference Systems (FIS) and the technique used for adjusting of the model parameters is an offline version of the Expectation Maximization (EM) algorithm. In order to automate the application of the methodology and facilitate the analysis of the results, a tool that allows managing streamflow forecasting studies and visualizing their information in graphical form was developed. A case study was applied to the data from three Brazilian hydroelectric plants whose operation is under the coordination of the Electric System National Operator. They are located in the Grande basin, a part of the Parana basin with two main rivers: the Grande and the Pardo. The benefits of the model are analyzed using statistics calculations, such as: root mean square error, mean absolute percentage error, mean absolute error and mass curve coefficient. Besides that, graphics that compare the registered and predicted streamflow are presented. The results show an adequate performance of the model, leading to a promising alternative for daily streamflow forecasting.

A Stochastic Hydrothermal Decision Support System for Planning Operation: New Developments for the HIDROTERM Model

The Brazilian hydrothermal system consists of a completely linked network of 143 medium and large hydropower plants, 888 small hydropower plants, and 1602 thermal and 82 wind power plants, with a total installed capacity of 128,570 MW. The hydropower plants produce, on average, 91% of the total electricity consumed in the country, while the complementary thermal system is dispatched mainly during periods of drought. In our previous studies, we developed a nonlinear programming model, HIDROTERM, to optimize the management and operation of the hydrothermal system, considering individual hydropower plants, thermal generation and exchange, multiple uses of the water, and system expansion. The model is deterministic. In this paper, we develop a new version of HIDROTERM to incorporate the stochasticity of the inflows in the formulation. Additionally, hourly load variation is represented by three levels: peak, base, and low. The proposed approach is based on a two-stage stochastic programming with recourse. In the first stage (first time period) the system passes from its initial state to the final state based on deterministic inflow forecasts. From the second time period on (the second stage), the state of the system branches out according to inflow scenarios. The branching can be scaled up gradually until the end of the planning horizon. New developments are made in the formulation, interface, database and the underlying simulation model. The newly developed integrated decision support system is being tested on the entire Brazilian hydrothermal system. 1 Assistant Professor, University of Sao Paulo; e-mail: rczambon@usp.br; ASCE/EWRI Member 2 Professor, University of Sao Paulo, Brazil; e-mail: mtbarros@usp.br; ASCE Member 3 Professor, University of Campinas; e-mail: franco@fec.unicamp.br 4 Assistant Professor, University of Campinas; e-mail: francato@fec.unicamp.br 5 Consulting Engineer; e-mail: jelopes1@gmail.com 6 Engineer, Companhia Energetica de Sao Paulo; e-mail: luis.nogueira@cesp.com.br 7 Distinguished Professor, UCLA; e-mail: williamy@seas.ucla.edu; ASCE Honorary Member 1563 World Environmental and Water Resources Congress 2013: Showcasing the Future

Towards Brazilian Corporations Better Stock Price Valuation and Operational Performance with Corporate Social Responsibility and Environmental Socio Responsibility

In this chapter is presented a Brazilian capital market good initiatives and improvements: we address some stock market improvements due to corporate governance practices structure development; we discuss correlation between CSR/ESG with operating performance and stock market returns; we describe initiatives undertaken since the middle of 1990s aiming at developing a more robust capital market; we also discuss CSR in a specific sector—the electricity industry, a big business in Brazil.

FUZZY INFERENCE SYSTEMS FOR MULTI-STEP AHEAD DAILY INFLOW FORECASTING

This paper presents the evaluation of a daily inflow forecasting model using a tool that facilitates the analysis of mathematical models for hydroelectric plants. The model is based on a Fuzzy Inference System. An offline version of the Expectation Maximization algorithm is employed to adjust the model parameters. The tool integrates different inflow forecasting models into a single physical structure. It makes uniform and streamlines the management of data, prediction studies, and presentation of results. A case study is carried out using data from three Brazilian hydroelectric plants of the Parana basin, Tiete River, in southern Brazil. Their activities are coordinated by Operator of the National Electric System (ONS) and inspected by the National Agency for Electricity (ANEEL). The model is evaluated considering a multi-step ahead forecasting task. The graphs allow a comparison between observed and forecasted inflows. For statistical analysis, it is used the mean absolute percentage error, the root mean square error, the mean absolute error, and the mass curve coefficient. The results show an adequate performance of the model, leading to a promising alternative for daily inflow forecasting.

Metrics and Risk Criteria Acceptance for Flood Control in Valleys Downstream Hydropower Plants

Given the importance of controlling floods in valleys and their impacts on the operation planning of hydropower plants, this research work aims at developing a contribution for finding a systematic metrics and risk criteria acceptance. It is assumed that each hydropower plant has a maximum flow constraint at downstream valley, thus requiring protection through operational procedures of the spillway and turbines. The decision about which risk level is acceptable for protection against flooding in the corresponding valleys should consider the nature, the complexity for control and the magnitude of the consequences of flooding. In general terms, high impacts will require low acceptable risk levels and, high complexity for flood control operation will require low acceptable risk levels. In order to describe the magnitude of consequences under flooding beyond the threshold level (maximum flow constraint), six severity descriptors were defined based on social impacts, possible fatalities, economic damages, operational damages, environmental damages and reputation losses to the image of the generation company. The severity descriptors are measured by using qualitative scales (low, moderate, high, catastrophic) with detailed instructions about the situations that leads to each position in the several scale levels. Similarly, five complexity operational flood control descriptors are also defined, with the corresponding qualitative scales. The proposed methodology is applied on a system of hydropower plants of the power generation company Companhia Energetica de Sao Paulo (CESP). This case study was developed with the collaboration of the technical staff of CESP, including professionals of different branches of the company. The results exhibits consistency, thus revealing the proposed methodology as an useful tool for supporting decision about risk criteria acceptance.

A Eficiência Energética na Operação Ótima de Estações Elevatórias de Esgoto

Thisw orkp resentsas tudyo fe nergye fficiencyf ort he � p lanningo ft heo perationo fe levatorys tationso fs ewer�( EEE).�I t � w asv erifiedn ecessityo ft hes tudyat imet hatt heo utflowo fs ewer � g eneratedt ot hel ongo neo ft hed ayi sc hangeablei na greement � c urvep resentedi nt hew orka nda lsot hec ostf orK who fe lectric � e nergyi sn otc onstantd uringt he�2 4�h ourso ft hed ay.�A heado ft his � s ituationam odelo fo ptimizationt hrought het echniqueo fl inear � p rogrammingw asf ormulatede ntirem ixingw herei ti sl ookeds et � a ppointmentst hed rivea ndd isconnectiono fh ydraulicalb ombsw ith � t heo bjectivet om inimizet het otalc ostw ithe lectrice nergy. �F orc ase � s tudyi tw aso ptedt os hapet hee levatoryf inals ystemo fs ewero fa � c ityo ft heS aoP auloi nteriort hatr epresentsap roblems ufficiently � t ypical and enough to validate the methodology developed. 1. INTRODUCAO Osprocessosdetratamentodeefluentesdomesticose � industriaise xperimentarama vancostecnologicosconsiderav eis � nas � ultimasdecadas. � Porem, � no vosdesaf iosprecisamser � assumidoscomo, � pore xemplo, � asquestoesoperacionais � pertinentes a estes sistemas. Em muitos casos as condicoes topograficasdascidadesebairrosnemsemprepermitemo � escoamentoporgra vidadedosefluentes, � noscoletores, � ate � a � estacaodetratamentodeefluentes �(ETE). �Porestarazao, �f az-se � necessarioconstruirestacoesele vatoriasdeefluentes �(EEE), �para � conduzirosefluentesemcondutosforcados, �transpondobacias, � sendo necessario para isso vencer pontos de cotas mais elevada, e em certos trajetos voltar a escoar por gravidade. Em certos casos o bombeamento pode ser necessario a distâncias consideraveis. No casodosemissariossubmarinosparalancamentodeefluentes, �a � linha de recalque pode ter varios quilometros. � Oscustosoperacionaisnasestacoesele vatoriasde � efluentes �(EEE) �atingemcifrasele vadasparaosmunicipios. �Uma � taref aimportante �e �procurarmodularaoperacaodasestacoes � ele vatorias buscando a reducao dos custos diretos e indiretos e melhoraraef icienciadasestacoesele vatoriasdeefluentes, � seja � pela reducao dos custos com a manutencao ou pela economia direta com energia eletrica. � Estetrabalhotemcomoobjeti vof azerumplanejamento � deumaestacaoele vatoriadeefluentes � (EEE) � emontarum � modelodeprogramacaolinearinteiramistanoMicrosoft � Excelparaagendaroacionamentodasbombasemumaestacao � ele vatoriavisandoreduzirocustocomener giaeletrica. � Oestudo � comhorizontedeplanejamentodiario � (24 � horas) � einterv alosde � discretizacao a cada 10 minutos, levando em conta os parâmetros hidraulicos da EEE, numero e potencia das bombas de recalque, bem como custo da energia eletrica nos intervalos analisados.