technical papers - latiniahr.comlatiniahr.com/docs/journal_5.pdf · american journal of hydropower,...

American Journal of Hydropower, Water and Environment Systems, july 2016 1

Volume 5 • Out. 2017ISSN 2317-126X • US$: 15.00

AmericAn JournAl of Hydropower, wAter And

environment SyStemS

Technical Papers

06 DESIGN AND BUILD-UP OF A SMALL HYDROELECTRIC POWER PLANT FOR ENGINEERING TEACHINGTakatsuka, Jessica Pereira; Caldeira, Letícia Gonçalves; Oliveira, Danilo dos Santos; Noleto, Luciano Gonçalves; Velasco, Loana Nunes; Els, Rudi Henri Van

11 HYDRAULIC TRANSIENTS IN PENSTOCKS: COMPARISON OF METHODS RUNGE-KUTTA AND CHARACTERISTICS IN LOAD REJECTION SOLUTIONMarra, João M.; Gramani, Liliana M.; Santos, Christian W.; Kaviski, Eloy

19 FEASIBILITY ASSESSMENT FOR DEPLOYMENT OF MINI HYDROPOWER PLANT IN CONSOLIDATED RESERVOIR Mendes, Thiago Augusto; Savas, Tuna Kan

26 STRATEGIC ENVIRONMENTAL ASSESSMENT – SEA OF THE HYDROELECTRIC GENERATION PROGRAM OF MINAS GERAIS – HGPMG AS AN ENVIRONMENTAL MANAGEMENT INSTRUMENTFilho,Wilson Pereira Barbosa; Silva, Lívia Maria Leite da; Costa, Antonella Lombardi; Arantes, Irene Albernaz; Silva, Nathan Vinícius Martins da; Oliveira, Karina Aleixo Benetti de

35 SOFTWARE FOR GENERATING FLOW DURATION CURVES VIA REGIONALIZATIONCordeiro, Adria Lorena de Moraes ; Blanco, Claudio J. C.; Silva, Raimunda da Silva e; Pessoa, Francisco Carlos Lira

Published with the support of Hydraulic Machinery and Systems

International Association

WORKING GROUPlatinamerican

Editorial We now come to the AJHPWS´s fifth edition.This publication is one of the actions undertaken by the Latin American Working Group of IAHR´s

Hydraulic Machines and Systems Committee.The fight in searching new papers and prestige from scientific community is incessant. An

effective contribution for sustainable development is one of our purposes.All our researches have the potential to promote scientific knowledge and to support new policies

aiming the development of new technologies from the technical, social and economic point of view, in addition to subsidize sustainable development and the quest for a better future.

Thus, dissemination of knowledge, methodologies and procedures of physical phenomena scientific modeling and solutions to reach technological development is one of the groups´ goals and consequently, of this journal.

In this case, this journal gradually becomes an eclectic vehicle within the limits of water resources and environment, if there are, and in addition it is interesting for the academy, considering that most part of papers come from research groups of several universities and research centers distributed in Brazil and Latin America.

This edition addresses several subjects such as: the project and building of a small hydropower plant aiming to become a learning tool for teaching and training of engineering students; suitability of an existing reservoir to operate as a mini hydropower plant, according to regulatory environment of not centralized micro generation in Brazil; comparative studies of methodologies for hydraulics transient calculation and finally, studies addressing management issues of water resources.

We do hope to contribute in any way in this direction. We look forward you to appreciate reading of selected papers for this edition of AJHWES.

Yours faithfully, Geraldo Lucio Tiago Filho

Editor in Chief

Regina Mambeli BarrosTechnical Editor

American Journal of Hydropower, Water and Environment Systems

IAHR DIVISION I: HYDRAULICSTECHNICAL COMMITTEE: HYDRAULIC

MACHINERY AND SYSTEMS

Editors in Chief Prof. Geraldo Lucio Tiago Fº - UNIFEIProf. Eduard Egusquiza - UPC

Executive Editors Prof. Carlos Martinez - UFMGEng. Humberto Gissoni - VOITH

Technical EditorsProf. Regina Mambeli Barros - UNIFEIProf. Cecilia Lucino - UNLP

Journalist in chargeAdriana Barbosa MTb - MG 05984JP

Graphic Projec/ DiagrammingLidiane Silva

Circulation1,000 copies

Federal University of Itajubá - UNIFEIAv. BPS, 1303 - Bairro Pinheirinho

Itajubá - MG - Brasil - CEP: 37500-903

ISSN 2317-126X


environment SyStemS

LAWG-IAHR Executive Secretariat Lucia Garrido Rios

[email protected]

Catalographic card prepared by Mauá Library – Librarian Margareth Ribeiro – CRB_6/1700

R454

American Journal of Hydropower, Water and Environment Systems, LAWG-IAHR, v.1, 2014 – Itajubá: LAWG- IAHR, 2015 - v.5, out. 2017.

Trimestral, Editors Chief: Geraldo Lúcio Tiago Filho/Eduard Egusquiza Journalist in Charge: Adriana Barbosa – MTb_MG 05984 ISSN 2317-126X

1. Hydropower. 2. Water. 3. Enviroment Systems. II. Latin American Working Group

2 American Journal of Hydropower, Water and Environment Systems, out 2017

American Journal of Hydropower, Water and Environment Systems

A publication of Latin American Working Group of the International Association for Hydro-Environment Engineering and Research-IAHR

All papers must be submitted in English. In case the author wants to translate the article through the journal all costs for the translation will be charged on the account of the author.

1. Formatting articles

1.1. Article structure

1.1.1 Subdivision - numbered sections

Divide your article into clearly defined and numbered sections. Subsections should be numbered 1.1 (then 1.1.1, 1.1.2, ...), 1.2, etc. (the abstract is not included in section numbering). Use this numbering also for internal cross-referencing: do not just refer to ‘the text’. Any subsection may be given a brief heading. Each heading should appear on its own separate line.

1.1.2 Format

All text of the manuscript must be located within a 170 mm by 252 mm rectangle of a white A4 page or within 170 mm by 240 mm for the letter format. The margins are given in Table 1. An example of the page format is given in Fig. 1

[Table 1]: Page margin for manuscripts.

Margin Position Top Bottom Left Right

Margin size (cm) 2.0 2.5 2.0 2.0

All text should be single spaced, black and in 12-point type. “Times News Roman” or a similar proportional font should be used. Total length 15 pages in Word.

The terminology given in the IEC Technical Report for the Nomenclature of Hydraulic Machinery is recommended.

Introduction State the objectives of the work and provide an adequate

background, avoiding a detailed literature survey or a summary of the results.

Material and methods Provide sufficient details to allow the work to be reproduced.

Methods already published should be indicated by a reference: only relevant modifications should be described.

Theory/calculation A Theory section should extend, not repeat, the background

to the article already dealt with in the Introduction and lay the foundation for further work. In contrast, a Calculation section represents a practical development from a theoretical basis.

Results Results should be clear and concise.

Discussion This should explore the significance of the results of the

work, not repeat them. A combined Results and Discussion section is often appropriate. Avoid extensive citations and discussion of published literature.

Conclusions The main conclusions of the study may be presented in a

short Conclusions section, which may stand alone or form a subsection of a Discussion or Results and Discussion section.

INSTRUCTIONS FOR AUTHORS

References

Within the text, references should be cited in numerical order according to their order of appearance. The numbered reference citation within text should be enclosed in brackets.

After the second edition all papers must have at least one reference of the American Journal of Hydropower, Water and Environment Systems.

Example: It was shown by Prusa [1] that the width of the plume decreases under these conditions.

In the case of two citations, the numbers should be separated by a comma [1,2]. In the case of more than two references, the numbers should be separated by a dash [5-7].

List of References. References to original sources for cited material should be listed together at the end of the paper; footnotes should not be used for this purpose. References should be arranged in numerical order according to the sequence of citations within the text. Each reference should include the last name of each author followed by his initials.

(1) Reference to journal articles and papers in serial publications should include:

• last name of each author followed by their initials• year of publication• abbreviated title of publication in which it appears• full title of the cited article in quotes, title capitalization• volume number (if any) (Do not include the abbreviation,

“Vol.”)• issue number (if any) in parentheses (Do not include the

abbreviation, “No.”)• inclusive page numbers of the cited article (include “pp.”)

(2) Reference to textbooks and monographs should include:

• last name of each author followed by their initials• year of publication• titles in examples may be in italic• publisher• city of publication• inclusive page numbers of the work being cited (include “pp.”)• chapter number (if any) at the end of the citation following

the abbreviation, “Chap.”

(3) Reference to individual conference papers, papers in compiled conference proceedings, or any other collection of works by numerous authors should include:

• last name of each author followed by their initials• year of publication• full title of the cited paper in quotes, title capitalization• individual paper number (if any)• full title of the publication• initials followed by last name of editors (if any), followed by

the abbreviation, “eds.”• publisher• city of publication• volume number (if any) in boldface if a single number,

include, “Vol.” if part of larger identifier (e.g., “PVP-Vol. 254”)• inclusive page numbers of the work being cited (include “pp.”)

(4) Reference to theses and technical reports should include:

• last name of each author followed by their initials• year of publication• full title in quotes, title capitalization• report number (if any)• publisher or institution name, city

American Journal of Hydropower, Water and Environment Systems, out 2017 3


Sample References[1] Ning, X., and Lovell, M. R., 2002, “On the Sliding

Friction Characteristics of Unidirectional Continuous FRP Composites,” ASME J. Tribol., 124(1), pp. 5-13.

[2] Barnes, M., 2001, “Stresses in Solenoids,” J. Appl. Phys., 48(5), pp. 2000–2008.

[3] Jones, J., 2000, Contact Mechanics, Cambridge University Press, Cambridge, UK, Chap. 6.

[4] Lee, Y., Korpela, S. A., and Horne, R. N., 1982, “Structure of Multi-Cellular Natural Convection in a Tall Vertical Annulus,” Proc. 7th International Heat Transfer Conference, U. Grigul et al., eds., Hemisphere, Washington, DC, 2, pp. 221–226.

[5] Hashish, M., 2000, “600 MPa Waterjet Technology Development,” High Pressure Technology, PVP-Vol. 406, pp. 135-140.

[6] Watson, D. W., 1997, “Thermodynamic Analysis,” ASME Paper No. 97-GT-288.

[7] Tung, C. Y., 1982, “Evaporative Heat Transfer in the Contact Line of a Mixture,” Ph.D. thesis, Rensselaer Polytechnic Institute, Troy, NY.

[8] Kwon, O. K., and Pletcher, R. H., 1981, “Prediction of the Incompressible Flow Over A Rearward-Facing Step,” Technical Report No. HTL-26, CFD-4, Iowa State Univ., Ames, IA.

[9] Smith, R., 2002, “Conformal Lubricated Contact of Cylindrical Surfaces Involved in a Non-Steady Motion,” Ph.D. thesis, http://www.cas.phys.unm.edu/rsmith/homepage.html

1.1.2 Essential title page information • Title. Concise and informative. Titles are often used in

information-retrieval systems. Avoid abbreviations and formulae where possible.

• Author names and affiliations. Where the family name may be ambiguous (e.g., a double name), please indicate this clearly. Indicate all affiliations with a number immediately after the author’s name and in front of the appropriate address. Provide the full postal address of each affiliation, including the country name and, if available, the e-mail address of each author.

• Author résumé. The author must inform the graduation degree, post graduation, affiliation and email address. The résumé must not exceed 150 characters.

• Corresponding author. Clearly indicate who will handle correspondence at all stages of refereeing and publication, also post-publication. Ensure that e-mail address and the complete postal address are provided. Contact details must be kept up to date by the corresponding author.

• Present/permanent address. If an author has moved since the work described in the article was done, or was visiting at the time, a ‘Present address’ (or ‘Permanent address’) may be indicated as a footnote to that author’s name. The address at which the author actually did the work must be retained as the main, affiliation address. Superscript Arabic numerals are used for such footnotes.

Abstract A concise and factual abstract is required. The abstract

should state briefly the purpose of the research, the principal results and major conclusions. An abstract is often presented separately from the article, so it must be able to stand alone. For this reason, References should be avoided, but if essential, then cite the author(s) and year(s). Also, non-standard or uncommon abbreviations should be avoided, but if essential they must be defined at their first mention in the abstract itself.

Keywords

Immediately after the abstract, provide a maximum of 6 keywords, using American spelling and avoiding general and plural terms and multiple concepts (avoid, for example, ‘and’,

‘of’). Be sparing with abbreviations: only abbreviations firmly established in the field may be eligible. These keywords will be used for indexing purposes. Abbreviations

Define abbreviations that are not standard in this field in a footnote to be placed on the first page of the article. Such abbreviations that are unavoidable in the abstract must be defined at their first mention there, as well as in the footnote. Ensure consistency of abbreviations throughout the article. Acknowledgements

Collate acknowledgements in a separate section at the end of the article before the references and do not, therefore, include them on the title page, as a footnote to the title or otherwise. List here those individuals who provided help during the research (e.g., providing language help, writing assistance or proof reading the article, etc.). Nomenclature and units

Follow internationally accepted rules and conventions: use the international system of units (SI). If other quantities are mentioned, give their equivalent in SI. Math formulae

Present simple formulae in the line of normal text where possible and use the solidus (/) instead of a horizontal line for small fractional terms, e.g., X/Y. In principle, variables are to be presented in italics. Powers of e are often more conveniently denoted by exp. Number consecutively any equations that have to be displayed separately from the text (if referred to explicitly in the text).

Footnotes Footnotes should be used sparingly. Number them consecutively

throughout the article, using superscript Arabic numbers. Many wordprocessors build footnotes into the text, and this feature may be used. Should this not be the case, indicate the position of footnotes in the text and present the footnotes themselves separately at the end of the article. Do not include footnotes in the Reference list. Table footnotes

Indicate each footnote in a table with a superscript lowercase letter.

Artwork

Electronic artwork General points

• Make sure you use uniform lettering and sizing of your original artwork.

• Save text in illustrations as ‘graphics’ or enclose the font. • Only use the following fonts in your illustrations: Arial,

Courier, Times, Symbol. • Number the illustrations according to their sequence in the text. • Use a logical naming convention for your artwork files. • Provide captions to illustrations separately. • Produce images near to the desired size of the printed

version. • Submit each figure as a separate file.• Pictures, graphics and images must be submitted in a JPG

or GIF format with 300 dpi.

2 Conducting the Review

2.1 OriginalityYou might wish to do a quick literature search using tools

such as Scopus to see if there are any reviews of the area. If the research has been covered previously, pass on references of those works to the editor.


2.2 StructureConsider each element in turn: Title; Abstract; Introduction (It should describe the experiment, the hypothesis(es) and the

general experimental design or method); Method; Results; Conclusion/Discussion; Language: you do not need to correct the English. You should bring this to the attention of the editor, however.

2.3 Previous Research

If the article builds upon previous research does it reference that work appropriately? Are there any important works that have been omitted? Are the references accurate?

2.4 Ethical Issues

Plagiarism: If you suspect that an article is a substantial copy of another work, please let the editor know, citing the previous work in as much detail as possible

Fraud: It is very difficult to detect the determined fraudster, but if you suspect the results in an article to be untrue, discuss it with the editor

AUTHORIZATION FOR PUBLICATION OF PAPERS

LICENSE FOR USE OF INTELLECTUAL WORK (Author)

For this private instrument the AUTHOR, below signed authorizes the IAHR Latin American Working Group, to publish its work authorship, without any obligation and in exclusiveness character for the period of six months starting from the publication in the AMERICAN JOURNAL OF HYDROPOWER, WATER AND ENVIRONMENT SYSTEMS, or in another official publication of IAHR.

In case of joint authorship, the first author signs as AUTHOR, assuming before IAHR the commitment of informing the other authors of the granted license.

AUTHOR (full name in form letter):

Title of the Paper:

JOINT AUTHORS [full name in form letter]:

ADDRESS:

.

Email:



Technical Papers

06 DESIGN AND BUILD-UP OF A SMALL HYDROELECTRIC POWER PLANT FOR ENGINEERING TEACHINGTakatsuka, Jessica Pereira; Caldeira, Letícia Gonçalves; Oliveira, Danilo dos Santos; Noleto, Luciano Gonçalves; Velasco, Loana Nunes; Els, Rudi Henri Van

11 HYDRAULIC TRANSIENTS IN PENSTOCKS: COMPARISON OF METHODS RUNGE-KUTTA AND CHARACTERISTICS IN LOAD REJECTION SOLUTIONMarra, João M.; Gramani, Liliana M.; Santos, Christian W.; Kaviski, Eloy

19 FEASIBILITY ASSESSMENT FOR DEPLOYMENT OF MINI HYDROPOWER PLANT IN CONSOLIDATED RESERVOIR Mendes, Thiago Augusto; Savas, Tuna Kan

26 STRATEGIC ENVIRONMENTAL ASSESSMENT – SEA OF THE HYDROELECTRIC GENERATION PROGRAM OF MINAS GERAIS – HGPMG AS AN ENVIRONMENTAL MANAGEMENT INSTRUMENTFilho,Wilson Pereira Barbosa; Silva, Lívia Maria Leite da; Costa, Antonella Lombardi; Arantes, Irene Albernaz; Silva, Nathan Vinícius Martins da; Oliveira, Karina Aleixo Benetti de

35 SOFTWARE FOR GENERATING FLOW DURATION CURVES VIA REGIONALIZATIONCordeiro, Adria Lorena de Moraes ; Blanco, Claudio J. C.; Silva, Raimunda da Silva e; Pessoa, Francisco Carlos Lira

IAHR DIVISION I: HYDRAULICSTECHNICAL COMMITTEE: HYDRAULIC

MACHINERY AND SYSTEMS

Scientific Committee

Alexandre Kepler

André Mesquita

Antonio Brasil Júnior

Arthur Leotta

Augusto Nelson Viana

Benedito Márcio de Oliveira

Carlos Barreira Martinez

Cecilia Lucino

Daniel Fernández

Daniel Rodriguez

Edmundo Koelle

Facundo González

Fernando Zárate

Gabriel Tarnowski

Geraldo Lucio Tiago Filho

Humberto de Camargo Gissoni

Jaime Espinoza

José Carlos Amorim

José Cataldo

José Geraldo P. de Andrade

Juan Carlos Cacciavillani

Lubienska Cristina Lucas Jaquie Ribeiro

Luciano dos Santos

Miguel Tornell

Orlando Anibal Audisio

Rafael Acedo Lopes

Regina Mambeli Barros

Ricardo Vasconcellos

Roque Zanata

Segen Farid Estefen

Sergio Galván

Sergio Liscia

Ticao Siguemoto

Victor Hidalgo

Zulcy de Souza

Number 5 Out 2017


environment SyStemS


Design and Build-up of a Small Hydroelectric Power Plant for

Engineering Teaching1 Takatsuka, Jessica Pereira; 1 Caldeira, Letícia Gonçalves; 1 Oliveira, Danilo dos Santos,

1 Noleto, Luciano Gonçalves; 1 Velasco, Loana Nunes; 1Els, Rudi Henri Van

1Faculdade UnB Gama - Universidade de Brasília (UnB), Área Especial 2 Lote 14 Setor Central Gama-DF, Cep: 72405-610 - (55 61) 3107 8219

ABSTRACT

The majority of power generation in Brazil is made by hydroelectric power plants and projections shows that this scenario will hold into the future. Therefore it is essential to study the process of energy conversion, from the water movement until its consumption in electric form. That study will contribute in the formation of human resources and development of engineers at the field of energy production and conversion. The objective of this work is to project and build-up a hydro power plant inside the Thermofluids Laboratory of University of Brasilia-Gama Campus. The project encompasses the assembly of a water pipe to give the plant its head, the installation of a small Indalma turbine, a coupling device and a load center composed by lamps to assess the energy consumption. The project consists in evaluate the head losses at the water pipe, measurements for the hill diagram of the turbine, design and installation of the coupling between turbine and generator, and the design of the load center. In order to analyze the energy generated, tests with the generator and the turbine separated from each other were performed to obtain the output voltage, the me chanical power and efficiency of the turbine in nominal conditions. The hydraulic circuit and the coupling operated adequately after its installation. When the generator was coupled to the turbine, the latter had to operate below its optimal operation point due to a limitation of the generator. The load center was able to consume the electrical power given by the generator. Despite the generator limitations, the build-up of the power plant was successful, where one could observe the entire process of energy conversion.

KEYWORDS: Indalma Turbine. Hydropower Plant. Teaching methods. Coupling.

1. INTRODUCTION

According to data from [1], over 60% of the power plants in Brazil are hydroelectric. Likewise, close of 30% of the power plants in construction in Brazil are also hydroelectric. Therefore, one can note the predominance of this kind of power generation at the Brazilian energetic context, even with the availability of other sources. Those power plants are composed by a turbine-generator combination, that transforms mechanical power output of the hydraulic turbine in electric power.

That combination is obtained by a mechanical device that couples both machines. Power plants that has small values of power represent also a form to address the energy demands in Brazil, mainly in isolated communities. Those plants have small environmental impact compared with big power plants due to its dimensions [2, 3].

In order to address the energy demands, hydro power plant rehabilitation [4] and the use of small hydro power plants are studied in order to take the most of those enterprises. As a consequence, there is constant research for new technologies and equipment for energy generation, conversion and transmission. These research brings additional demands for human resources with specialized and transversal competencies in renewable energy. Because of that demand, engineering teaching must address those demands.

Within the context of engineering schools, the use of a power plant model allows to correlate the learning of theories involved in such a plant with practice experiences. This model would facilitate the learning of basic turbomachinery concepts, power analysis and management of the power output. The thermofluids laboratory of University of Brasilia - Gama Campus has a experimental setup of a hydraulic turbine, that allows the experimentation of small turbine models. This setup can be transformed into a complete power plant that can be use into

research and human resources formation. The entire process of energy conversion, transmission and consumption, from the flow to the generator outlet can be mapped and studied.

The energy engineering undergraduate course of UnB-Gama Campus aims to graduate engineers with competence to study modern energy conversion problems, such as generation, transmission, regulation and final use of that energy. Also, environmental and social issues are also present at the course curriculum. Its profile is of a electro-mechanical engineer with studies into portions of mechanical, chemical and electrical engineering, and studies into economics and regulation laws. Concerning hydroelectric plants, the student gets in touch with concepts of transport phenomena, fluid dynamics, turbomachinery, up to a course into hydroelectric power plants.

Therefore, the main goal of this work is the build-up and setup of a hydro power plant for teaching purposes at the thermofluids laboratory of UnB-Gama campus. The setup of the hydraulic circuit, the turbine, generator, its coupling, and the load center will be shown. Results concerning head losses, turbine experiments, coupling project and load center testings will be presented.

2. MATERIALS AND METHODS

In order to provide the turbine the mechanical power, a hydraulic circuit was projected and constructed at the laboratory, as shown in figure 1. This circuit has a 1000-liters reservoir, a water pump of 25 CV, and tubes of 0,1016 m and 0,1524 m. The water pump is controlled by a frequency inverter, allowing a better control of the flow rate and pressure of the circuit. The circuit has manual valves that can set a constant head, conducting any additional water to a drain pipe. This valve setup avoids unnecessary turbulence at the flow, which can impact at the turbine eciency. The entire hydraulic system was developed to allow the measurement of all data with simple analogical

American Journal of Hydropower, Water and Environment SystemsPublisher: Acta Editora/LAWG-IAHRDOI:10.14268/ajhwes.2017.00046ISSN: 2317-126XSubject Collection: Engineering, Subject: engineering, measurement, environment Systems


instrumentation and additional instrumentation coupled with computers. Data of head, flow rate, rotation force and rotation speed can be measured by those instrumentations. This setup allows a maximum gross head of 7 meters.

[Figure 1: Bench parts.]

Where:1. Frequency Inverter;2. Electrical Motor;3. Water Pump;4. Indalma Turbine;5. 1000 l-Water Tank;6. Turbine Water Intake Tube;7. Flow Rate Sensor;8. Triangular Spillway;9. Load Cells;10. Inductive Sensor;11. Manual Valves

The turbine used was a Indalma turbine, as showed in figure 2. This turbine was developed as a modification of a Francis turbine. Its main innovation is the use of aspects of impulse turbines and reaction turbines into a configuration that allows its functioning without a distributor. The Indalma turbine was developed to work into hydro power plants with power output below to 10 kW up to 1000 kW at the Amazon region. This region has demands for turbomachinery of easy assembly and simplified operation and maintenance. Since the turbine does not have distributor or a mechanical control for power output and flow rate, it simplifies its use into those kinds of hydro power plants. The turbine was also equipped with a DI15 Digital Indicator that is coupled with a rotation sensor. The indicator shows the rotation speed at the axis of the turbine in RPM.

[Figure 2: Indalma Turbine.]

(a) CAD Drawing

(b) Installed Indalma Turbine

One form to couple two rotative machines is using transmission elements. Those elements are flexible and transmit mechanical power or rotative movement. Typical examples of transmission elements are belts with pulleys, axis and cables. The use of a belt as a transmission element allows the transmission of rotation movement from one axis to another, where each axis has a pulley at its extremities [5]. The belt employed is a 90 cm length, V-section belt, who fits at the pulleys without sliding. A moving base was employed to adapt the generator to the turbine height and to allow the traction of the belt between the pulleys. The generator was bolted at the base to allow this adaptation, as showed in figure 3.

[Figure 2: Turbine-Generator Setup.]

(b) Generator

(a) Turbine-Generator Coupling

The employed generator is a three-phase synchronous machine with one pair of poles (Figure 3(b)) and an excitation system MPL-3305M MINIPA (0 to 32 V and 0 to 5 A). A multimeter was used to measure the output voltage at the machine terminals during the test.

The load is composed by six lamps, where three of them has 60W-220V and the other three has 40W-220V. Their choice is justified by the fact that they behave like resistors and the electrical power consumed is visibly noticed.

In a first moment, a monophasic circuit where all lamps are set in parallel was assembled. Each one has a switch to allow the load variation. However, connecting a monophasic load in a triphasic machine allows the machine to be unbalanced. This unbalance can cause the appearance of a negative-sequenced electrical current, vibration and a decrease in the nominal rotation. Because of that the load cell circuit has to be transformed into a triphasic circuit.


The result of this transformation is a circuit with a star connection. All the phases of this circuit are composed by two parallel-assembled lamps, each one connected to a switch, according to figures 4(b) and 4(c). Also, for the tests, a rectifier, a voltage source and a voltage regulator were employed to control and provide a direct current to excitate the generator. The load setup is showed at figure 4(a).

[Figure 4: Load Center.]

(b) Monophasic connection

(c) Triphasic connection

(a) Load Center

3. RESULTS

3.1. Head Losses

The Darcy-Weisbach equation (Equation 1) was employed to evaluate the head loss hf at the hydraulic circuit [6]:

(1)

Where f is the friction factor, L is the tube length, D is the tube diameter and u is the flow velocity. The flow ratio Q was measured by a electronic flow ratio sensor. With the water flow rate and the diameter, the Reynolds number was calculated using equation 2 for both diameters:

(2)

Where A is the round section area and n is the kinematic viscosity. A measured flow rate of 0,0512 m3/s yield the Reynolds number values displayed on table 1:

[Table 1]: Reynolds Number for each tube.

Diameter (m) Area (m2) Re

0,1016 0,0081 642212,35

0,1524 0,0182 428729,67

One can note that the Reynolds number for both cases is above 2300. According to [6], the flow is fully turbulent with those values of Reynolds number. Therefore, the Moody diagram is employed to evaluate the friction factor f . With this data, one can calculate the head losses at the straight tubes. For the head losses at parts of the hydraulic circuit, all the components are listed at table 2, with their respective head losses:

[Table 2]: Minor head losses.

Part Head Loss (m)

Two Bends 0,0595

Four Tees 0,0151

One Elbow 0,0026

The total head loss of the entire hydraulic circuit, including the minor losses, is hf= 0,1588 m.

The majority of the head losses at the circuit is at the upward tubes. However, in order to obtain the net head delivered to the turbine, one must take only the loss at the pipes where the water is going downward. This head loss is equal to hf d= 0,0447 m, where the upward tubes and all the minor losses before the downward tube were subtracted from the total head loss.

3.2. Hill Diagram and Power Output

The used gross head for the hydraulic circuit is equal to 6,385 meters of water column (mwc), which is below the maximum head for safety reasons. By subtracting the downward head loss calculated above from the gross head, one can conclude that the net head is equal to 6,34 mwc.

With this head, it is possible to obtain the mechanical power output of the turbine.

With the flow rate and the net head, one can estimate the hydraulic power received by the turbine. The overall eciency for both the turbine and the generator is 0,675, therefore one can

estimate the power that the turbine will deliver to the generator using equation 3:

(3)

Where P is the power in kW, η is the eciency and g is the gravity. Several operating conditions of the turbine regarding the rotation, the power output and the eciency of the turbine were performed. These tests allowed the plotting of the hill diagram of the turbine, showed at figure 5.

The diagram shows where are the best functioning points to operate the turbine.

[Figure 1: Bench parts.]


Using the eciency and equation 3, the power output will be equal to 0,3004 kW. However, the mechanical power output of the turbine is too high for the generator. In order to be able to employ the described generator and to be able to use the projected load center, the turbine functioning was adjusted to fit the needed power value of the generator. To reduce the power output to the desired value, the hill diagram was employed to evaluate the new operation point. The chosen condition for the turbine provides 200 W of power is if the turbine rotation speed is set at 1080 RPM. This power and rotation values were used to the following calculations of the present work. To achieve those values, the head was adjusted with the valves and the pump rotation, using the hill diagram as a guide. The output power value given by the hill diagram was confirmed by the load cells.

3.3. Coupling and Voltage Output

The need of the coupling comes of the fact that the turbine has a nominal rotation speed of 1080 RPM and the generator has a nominal rotation speed of 3000 RPM. Therefore, the coupling aims to increase the rotation output of the turbine. To achieve this objective, a set of two pulleys and a belt were employed. The pulley that goes at the turbine has a diameter of D1=14,2 cm.

Therefore, having the rotations and this diameter, one can calculate the diameter of the generator pulley using equation 4:

(4)

Applying the previous data, one can find that the generator pulley must have a diameter of D2 = 5,11cm. For the assembly of the coupling a 5-cm pulley and a V-shaped belt of 90 cm of length were employed. A support composed by a moving base was attached to the generator to allow the belt traction and the proper rotation of the pulleys. This setup gave a 3067,2 RPM rotation to the generator for the turbine rotation, which is above the minimum required by the generator.

With the coupling operational, empty tests on the generator were performed in order to measure the output voltage. In the first test, the generator was excited with a voltage of 200 V, alongside a rectifier that provided a direct current to excite the generator. This test provided an output voltage of 9000,01 V, which is incompatible with the generator and its functioning, because the output is too high. The following tests were made by varying the pump rotation speed and employing a excitation voltage and current of 4 V and 0,02 A respectively. The measured values of output voltage for those tests can be seen at table 3:

[Table 3]: Generator Output for a Excitation Tension of 200 V.

Pump Rotation (RPM) Tension (V)

100 1000±01

80 720±01

60 410±01

After those tests, the generator was excited with 8 V and 0,03 A and the tests were repeated.

Although the measured output voltage dropped, it is still high for the generator. The use of a fixed voltage to excite the generator produced high values of output voltage, which prevented the use of this output for the load center. Also, it was noted the occurrence of a voltage decrease. To solve those

issues, a voltage regulator was connected to the excitation apparatus in order to alter the voltage output to acceptable values. The tests with the voltage regulator produced line values of 46,415 V and phase values 2205 V, that allowed the use of this output to the load center. The tests with this configuration can be seen in table 4:

[Table 4]: Generator Output for a Excitation Tension of 8 V.

Pump Rotation (RPM)

Line Tension (V) Phase Tension (V)

100 200±5 115±475

80 160±5 92±385

60 100±5 57±735

3.4. Load center

When the load center was assembled, tests were performed to observe the right connection of each phase of the load, and to find any short circuit caused by wrong connections. The center was connected to 220 V. After these tests, another set of tests were conducted to check the connection between phases. The results showed that the load center is correctly connected. The next step was connect the load center to the generator. As previously mentioned, a voltage regulator was connected to the generator excitation to avoid the voltage decrease and to control the voltage output. The turbine rotation was fixed at 1080 rpm, which gave a generator rotation of 3067,2 rpm. The excitation voltage is 975 V in direct current. The voltage at the line and the phase are 346,415 V and 2205 V respectively. Those values were acceptable by the load center, and the result of this voltage at the center are shown at figure 6:

[Figure 6: Generator.]

One can note that the mechanical power generated by the turbine was converted into electrical power and consumed by the load center. Tests where the center unbalanced the electrical load were performed. For those tests, lamps of 40 W and 60 W were employed and some of those lamps were turned o to achieve the unbalance. The current frequency and values for each phase A, B and C are showed at table 5:

[Table 5]: Phase Currents.

Phase Current (A)

A 0,150±01

B 0,180±01

C 0,200±01


When the electrical load was changed, one noted that the remaining phases divided the electrical power. That fact was visibly at the load center, where some lamps lose their luminous intensity with the increase of the load. With those tests, the build-up was completed and the bench was fully operating as a 200 W hydroelectric power plant.

4. CONCLUSIONS

The present work described the setup and build-up of an experimental bench of a small turbine and generator to act as a hydroelectric power plant. This plant aims to be used as learning and teaching tool for the Energy Engineering students of University of Brasilia - Gama Campus. The design of the hydraulic circuit, turbine operation points, its coupling with the generator and the tests of the generator and the load center were showed.

Calculations were made to evaluate the head loss from the water inlet to the turbine inlet. With those results, the available mechanical power given by the fluid and its given head were calculated too. In order to compensate for the generator, the used turbine power output is lower than the maximum. Its value was calculated by the hill diagram after several tests with the turbine. The coupling was able to transmit the mechanical power to the generator, but the output voltage and current were too high for the load center. To solve this issue, an excitator and a voltage regulator were employed and acceptable values of current and tension were obtained and used at the load center. The center functioned adequately with and without all the lamps turned on.

Before the build-up, the experimental setup was able to perform experiments of pump performance and turbine eciency. Now, with the coupling with an generator and a load center, the setup can perform complete experiments of energy conversion, even with a limited generator. The energy engineering course at University of Brasilia-Gama Campus can now exploit transversal experiments on energy conversion, generation, transmission,

regulation and consumption, which covers both mechanical and electrical areas simultaneously. Also, research on mechanical load variation and regulation of the turbine with its eects on energy conversion and transmission can be exploited.

Concluding, the experimental setup was successfully transformed into a hydro power plant, but the generator limited the electrical power output. Further work will be performed into the use of a new generator, and the diversification of the load center, where more lamps and electrical equipments will be added to the center. Also, other points at the hill diagram will be used to evaluate the performance of the turbine and the generator. In the future, it is planned to perform research into energy generation management and quality with the educational use of the setup.

5. BIBLIOGRAPHY

[1] ANEEL. (2016). BIG Banco de Informações de Geração. Available in http://www2.aneel.gov.br/aplicacoes/capacidadebrasil/capacidadebrasil.cfm

[2] Silva, C. L., Nowarowski, G. A. A., Santoyo, A. H., Leon, V. E. P., Vilardell, M. C., Análise de Possibilidade de Expansão das Pequenas Centrais Hidroelétricas no Brasil: Um Estudo dos Limitantes e Potencialidades da Cadeia Produtiva à Luz da Sustentabilidade. Desenvolvimento e Meio Ambiente 27 (2016) pp 48-72.

[3] Yah, N. F., Oumer, A. N., Idris, M. S., Small Scale Hydro-Power as a Source of Renewable energy in Malaysia: A Review. Renewable and Sustainable Energy Reviews 72 (2017) pp. 228-239.

[4] Gomes, E. P., Bajay, S. V., Brazilian Hydroelectric Rehabilitation Potential and Viability. American Journal of Hydropower, Water and Environmental Systems 1 (2014)pp. 20-24.

[5] FRANCESCHI, A., ANTONELLO, M. G. (2014). Elementos de Máquinas. Santa Maria-RS: UFSM.

[6] White, F. M., Fluid Mechanics, 6th. Edition, 2008, Mcgraw-Hill.


Hydraulic Transients in Penstocks: Comparison of Methods Runge-Kutta

and Characteristics in Load Rejection Solution 1Marra, João M.; 2Gramani, Liliana M.; 3Santos, Christian W.; 4Kaviski, Eloy.

1Department of Maintenance Engineering, Itaipu Binational, Iguassu Falls, 85856-970, Brazil, e-mail: [email protected]; Tel: (+55 45)3520-2690; Fax: (+55 45)3520-38352Department of Mathematics, Federal University of Parana - UFPR, Curitiba, 81531-990, Brazil, e-mail: [email protected] for Advanced Studies in Dam Safety – FPTI, Iguassu Falls, 85.867-900, Brazil, e-mail: [email protected] of Hydraulic and Hydrology, Federal University of Parana – UFPR, Curitiba, 81531-990, Brazil, e-mail: [email protected]

ABSTRACT

This paper presents a comparative study of results obtained by the methods of Characteristics and Runge-Kutta in the numerical solution of governing equations for determining the pressure behavior in the hydraulic system of a Francis turbine during transients in its flow. For this purpose is analyzed the effects of using different discretizations for space and time in the results in both these methods. Also, a formulation that avoids numerical instability in the Method of Characteristics in hydraulic systems modeled with variable geometry is tested. In the solution for Runge-Kutta, the representation of hydraulic systems is made through equivalent electric circuits. The results validation is based on available data of transients recorded during load rejection testing in the Francis turbines of Itaipu Power Plant and has indicated that for a suitable mesh space-time the Runge-Kutta method presents accuracy and speed of processing that configures it as an alternative to the traditional Method of Characteristics for this type of estimation. Additionally, the equating used at the Method of Characteristics allowed to apply it for a pipeline with variable diameter without numerical instability was observed. As an application of this study is analyzed the possibility of changing the distributor's closing time law of these turbines, that provides more favorable values of overpressure due to water hammer and overspeed in the generating unit in load rejections using a more realistic representation of the hydraulic system of the turbine.

KEYWORDS: hydraulic transient, numerical simulation, water hammer, penstock, turbine.

1. INTRODUCTION

The regularization of an interconnected electrical system is a complex process and requires instant and permanent action to equilibrate the natural oscillations and abrupt variations the load with generation. Also, should be equilibrated the swings and sudden changes provoked by equipment failure or temporary lack of energetic availability of some source as, for example, the wind and solar power, which increasingly are present in the Brazilian and world energy matrix.

In this context, the hydroelectric power plants are versatile in meeting the load variations and of the interconnected power system generation, due to the rapidity of power's response due to a favorable ratio of rotational inertia and hydraulic response. However, in meeting these variations, often these plants operate outside their optimal hydraulic conditions, including due to seasonal variation in hydraulicity or hydraulic crises, increasingly frequent by global warming. In this scenario, the machines of simple regulation how the Francis turbines, responsible for significant contribution in the hydroelectric generation in Brazil and the world, and also for 60% of the world hydraulic potential to be installed, are usually more sensible due its intrinsic characteristics, mainly concerning the efficiency and disturbances in the flow.

The knowledge of the pressure behavior in the hydraulic system of a hydraulic turbine during flow transients is fundamental in the penstock and generating unit design stage, and the correct estimate of this represents challenges due to the complexity of the actual installation of a hydroelectric plant. The pressure variations caused by water hammer in an abrupt load change could be quantified with accuracy through the Method of Characteristics. However, for oscillations associated the phenomena of resonance or hydraulic instability

during normal operation of the turbine, the representation of hydraulic systems through equivalent electric circuits solved by the numerical integration of Runge-Kutta presents some advantages in the mathematical modeling of the hydraulic system.

To verify the accuracy and speed time processing of the methodology indicated in this paper is made a comparative study of the numerical results using different space and time mesh discretizations for both methods, and also existing measuring data from a load rejection of an original hydroelectric plant.

Beyond the numerical verification of the guaranteed values of overpressure and overspeed during the design stage, another applic designer to make an optimization of the closing time law, reducing the experimental runs for reach this purpose.

2. GOVERNING EQUATIONS AND ELECTRICAL ANALOGY

The hydraulic circuit of hydroelectric pl plants is characterized by having much larger longitudinal dimension than the transversal, as an illustration of Fig. 1. In function of this typical configuration, the working fluid flow has predominant characteristics in the longitudinal direction and negligible temperature variation, allowing a representative one dimensional mathematical modeling of the dynamic flow behavior based on the momentum and mass conservation laws.

According to [2], the application of Newton's second law on a free body diagram of forces to an elastic element of dx length of the pipeline and continuity equation to the same element subjected to a hydraulic piezometric line results on the following governing equations system for the transient one-dimensional flow on the pipeline element, where ‘a’



[Figure 1: Scheme of typical hydraulic system of a hydroelectric plant ([1])]

(1)

(2)

On the above system the Eq. (1) is referred to the momentum equation and the Eq. (2) to a transport equation given by the mass conservation. The equations system formed is a hyperbolic first order non-linear partial differential equations system, for which the method of characteristics, based on finite differences, is traditionally used in its numerical solution for given initial and boundary conditions.

As stated at [3], the equations system above is analogous to electric wave propagation in electric conductors, wherein the flow Q corresponds to the electric current, and piezometric head H (or pressure) corresponds to voltage. Based on the analogy of the two systems, the parameters correspondents of the hydraulic system are qualified to traditional denominations of parameters R (Resistance), L (Inductance) and C (Capacitance) for an electric system, as indicated below:

(3)

(4)

In the hydraulic system the parameter R represents the loss of energy by dissipative effects, L and C represents, respectively, the effects of inertia and storage in volume. The parameter C is also denominated compliance because the storage effect is due to the fluid compressibility and the pipeline elasticity. Due to the dependence of the resistance R with the flow rate R(Q), the partial differential equations system (Eq. 3 and Eq. 4) is nonlinear. The apostrophe signal indicates that the values of parameters in the equations are per length unit:

(5)

The circuit of the hydraulic system equivalent to the electric circuit RLC is indicated on Fig. 2, where the index i and i+1 represents the state variables value (H, Q) at the opposite ends of the element considered.

[Figure 2: Scheme of the equivalent electric circuit of the elastic tube element Adapted from [4]).]

In function of the analogy between the hydraulic and electrical circuits, the governing equations of the hydraulic circuit can be obtained by applying the laws of Kirchoff and the law relating to the electrical voltage drop (or hydraulic pressure) on the elements of the circuit, as indicated on the Tab. 1, where I é the current and U the voltage.

[Table 1]: Analogy of electrical and hydraulic circuits.

Law Application Electric Hydraulic

1st Kirchhoff’s law Node law

2nd Kirchhoff’s law Mesh law

Ohm’s lawVoltage drop on

resistor

Lenz’s lawVoltage drop on

inductor

CapacitanceVoltage drop on

capacitor

3. SPATIAL DISCRETIZATION OF HYDRAULIC SYSTEM AND MODELING OF PIPELINE

In this simulation, all of the hydraulic pipeline stretches are modeled as elastics elements of steel, regardless of these being installed in apparent steel, embedded or concrete only.

3.1 For the Runge-Kutta method – RKM

For a generic pipe of length l, applying a discretization based on a central scheme, it can quantify the spatial variation of manometric height H, flow rate Q and the mean flow value at the node i+1/2, as, respectively, in the expressions indicated on Eq. (6):

(6)

The central scheme used at spatial discretization for the pipeline length l is shown at Fig. 3:

[Figure 3: One-dimensional spatial discretization of pipeline (Adapted from [4]).]

For the considered elastic tube, the scheme of the equivalent electric circuit to the adopted discretization of the hydraulic system is shown in Fig. 4:


[Figure 4: Elastic tube equivalent electric circuit (Adapted from [4]).]

Substituting the expressions of Eq. 6 in Eq. (3) and Eq. (4) and making R' dx = R, L' dx = L e C' dx = C is obtained an ODE system for one element of an elastic tube of length dx, that expressed in matrix form becomes:

(7)

In compact matrix form, the equation system (7) is reduced to Eq. (8), where is the state variable vector of the discretized system and A and B are 3x3 matrices:

(8)

For the elastic tube of length l discretized as indicated in Fig 3, the matrices [A] and [B] of (Eq. 11) have order 2n + 1 and the vectors of state (Eq. 9) and of boundary conditions (Eq. 10) have dimension ( 2n +1, 1):

(9)

(10)

(11)

At this work, the Runge-Kutta fourth order method in explicit form will be used for the integration of the Eq. (8), whose solution makes possible to know the time evolution of the pressure and flow rate at each node of interest of the mesh of the system during a hydraulic transient.

3.2 For the method of characteristics – MOC

The method of characteristics can be used widely to solve initial value problem relative to first order ODE and that when applied to a PDE with two variables the change of coordinates of the process transforms the PDE in ODE along certain curves called Characteristic Curves, over which the new variables will be constant in these curves, as stated in [5]. The application of the method of characteristics on the governing equations (1) and (2) results in two ODE systems (Eq. 12) correspondents to two characteristics equations relatives to the propagation of the wave flow positive direction (C+) and on opposite direction (C-). Conforming to [3], such systems of equations are:

(12)

The spatial discretization of the hydraulic system and the spatial-temporal adopted for the method of characteristics are respectively illustrated in Fig. 5.a and Fig. 5.b. On this process, waves travel with the celerity a along the characteristic lines, represented on the plane (x, t) by diagonals lines, obeying to the relationship a = ∆x/∆t.

[Figure 5: a) Spatial discretization of hydraulic [6]; b) Spatial and temporal discretization [6].]

According to [3] and [7], applying progressive finite differences to the derivatives of equations (12), integrating over the positive characteristic lines (C+) and negatives ones (C-), illustrated in detail in Fig. 6, and adapting their solution for a penstock with variable diameter is obtained the expressions of Eq. (13), where and the generalized position of the nodes at the space-time plane is indicate by the indexes i and j.

[Figure 6: Characteristics curves (Adapted from [6]).]

(13)

By solving the linear system represented by Eq. (13), is obtained the expression of Eq. (14) that quantifies respectively the amplitudes of pressure and flow rate in the hydraulic system in the discretized domain:

(14)

The use of Eq. (14) is an attempt to apply the MOC in modeling with geometric variation (diameter) of the pipeline of the hydraulic system, since the use of traditional expressions shown in Eq. (15) leads to numerical instability when the


system is not modeled with constant geometry as indicated in Fig. 5.a or to the necessity of using of a very refined spatial discretization to control the inherent instability, which increases severely the processing time.

(15)

4. MODELING OF HYDRAULIC SYSTEM

This section discusses the geometric modeling the variation of the diameter of the pipe along the hydraulic system of the turbines of ITAIPU Power Plant shown at Fig. 7.a, from the water to the outlet end of the spiral casing and also the modeling of the functional elements which were considered as concentrates (lumped), as shaft surge tank and turbine distributor.

[Figure 1: a) Hydraulic system of ITAIPU Power Plant [8]; b) Geometric modeling]

a)

b)

4.1 Pipeline

The variation of the penstock diameter at the input stream, the upper curve, straight stretch, lower curve and spiral casing hydraulic turbines of ITAIPU is shown in Fig. 7.b.

The coefficient of friction in hydraulic surfaces was obtained from data available of pressure drop in the hydraulic system and of the application of Darcy-Weisbach relationship, resulting in an average value of 0.025

4.2 Shaft surge tank

The duct to the purging of atmospheric air in the turbine and penstock priming and the niches of the entrance gate and of the stop-log existing on input stret normal operation or load rejection. The adopted mathematical model for this element on RKM and MOC are shown in Fig. 8.a and Fig. 8.b, respectively.

[Figure 1: Mathematical model of the shaft surge tank: a) RKM(Adapted from [4]); b) MOC (Adapted from [2])]

a)

b)

Solving the circuit obtains the Eq. (16) compatible with the discretization and state vector adopted in the application of Runge-Kutta for this element of the hydraulic system:

(16)

In the case of the method of characteristics, the modeling used for the ventilation duct was only based on the continuity equation, resulting in the equation indicated in the illustration of Fig.8.b.

4.3 Wicket gate

The discharge coefficient curve CD in function of the free area AW of the turbine distributor was calculated using the relation of Eq (17). Distributor area AW , flow rate QW , and the pressure Hn were obtained from an existing recorded digital data of simultaneous measurements at a full gate load rejection test performed at the commissioning of the turbine U18A in 2005. Calculated and approximated curves of C are indicated in Fig. 9.a. The flow rate measurement was based on Winter-Kennedy method, at whose constant was later determined using two absolute methods, Gibson and Ultrasonic by transit time. Due to the existence of a cut-off on the flow transducer near 250 m3/s, the flow rate curve was completed respecting the closing time law indicated in Fig. 9.b, resulting in the modeled flow rate curve used of the Fig. 9.c.

(17)

The curves for the discharge coefficient, closing time law and flow rate curve in the distributor are shown in Fig.9.a.

[Figure 9: a) Discharge coefficient; b) Closing time law; c) Flow curve.]


During simulation of the hydraulic transient, the flow rate Q in the distributor was obtained using the Eq. (18), where b is the height of the vanes, Z is the number of vanes and S is the opening related to the distributor.

(18)

According to [9], it’s necessary to perform series of computation to evaluate the influence of the turbine’s distributor closing time on guaranteed control values. To facilitate the analysis of the influence of the variation of closing time law in overpressure and overspeed, this was modeled considering the possibility of changing the closing time by changing the opening at t1 and the opening and time at t2 for any given distributor initial opening in t0, as illustrated in Fig. 9.b. The initial (0-t1) stretch of the curve of Fig.9.b. was modeled by a polynomial, the intermediate stretch between t1 and t2 by a straight line and the final stretch by an exponential curve. The flow rate curve of Fig. 9.c refers to the studied case with an initial discharge of 770 m3/s, very close the maximum possible according to the hill chart of the Fig. 10.a about the ITAIPU turbines, considering the 800 MW power limitation existing at these turbines. The measured pressure considered to comparison with simulated values was taken on a piezometric tap positioned at spiral case door at its mean elevation, as indicated in Fig. 10.b and Fig. 10.c.

[Figure 9: a) Hill Chart of the Itaipu turbines; b) Pressure measuring point; c) Elevation of the pressure tap.]

At the application of the present study was considered an installed power plant with data of measurement available to make possible an evaluation of the methodology used. However, a similar procedure may be used independently if the plant is already installed or still under design. Therefore, the discharge variation may be obtained numerically introducing at the equivalent electric circuit a downstream tip element representing the distributor how a lumped element with hydraulic resistance Rd and head losses Hd , as described at [4], and the vane opening S obtained by the preview distributor closing time law established.

4.4 Rotating parts

The sudden load rejection of a generating unit for decoupling thereof with the electrical system provides an unbalancing of torque between the turbine and generator, and a consequent increase in speed. Because of this, the turbine speed governor commands the closing of the turbine distributor, which in turn causes a transient hydraulic pressure in the penstock, known as water hammer. In this condition, assuming that the magnetic torque in the air gap torque in the generator cancels instantly, the rotation speed N of the rotating assembly becomes dominated by the mechanical torque Tmec and the rotational inertia J, according to Eq. (19):

(19)

Equation 18 can be integrated by separation of variables, whose discrete approximation of the solution given by Eq. (20) allows to obtaining the evolution of the rotation during the transient from the rejected power the turbine at rated speed. During the transient, turbine shaft power was evaluated by the expression P = γQtHnη, but without consider changing at the efficiency with the rotation variation. The turbine efficiency was obtained of its hill chart. The moment of inertia was achieved by existing measurements of the GD2 factor realized at type acceptance tests of the ITAIPU 60 Hz hydrogenerators, whose value was considered 328150 tm2, equivalent to 8.380E6 kg m2.

(20)

The intrinsic braking power Pb was obtained by assuming a linear variation of the losses dependent on voltage generator (2.1 MW) with rotation and a cubic variation with the rotation for the friction losses (2.1 MW) in the bearings and ventilation.

5. MESH SPACE AND TIME AND COMPUTING RESOURCES

The numerical simulations by the MOC require that minimum time interval in computational iterations respects the criterion of Courant-Friedrich-Levy, which establishes that the Courant number Cr = a . ∆t/∆x = a . n . ∆t/l must be equal to the unit for an explicit method. Although the RKM method in the explicit application doesn't be unconditionally stable, this requirement isn't necessary. For RKM the minimum Courant was 0.05 and the maximum was 1.0.

To evaluate the accuracy of both methods in representing the transient phenomenon and the impact of discretizations adopted in processing time, this study was conducted considering 8 different spatial discretizations (M1, M2, M3, M4, M5, M6, M7, M8) and 4 steps of time (T1, T2, T3 and T4), totaling 32 different configurations for mesh spatial and temporal. From a total of spatial discretizations, 4 were with uniform length elements and 4 with a non-uniform length of elements to reduce the total number of elements, for which was adopted a different discretization, but with homogeneous elements for the straight sections (2, 4, 6) of the modeled pipeline in Figure 7.b. The steps of time adopted aimed to work with unitary Courant at the MOC, considering the smaller spatial mesh element and maintained a constant ratio of 0.5 (T1/T2), 0.4 (T2/T3) and 0.25 (T3/T4) between the respective steps of each spatial configuration.

Thus, for example, the mesh M1.T1 has spatial discretization M1 and step time T1 corresponding to this discretization and so on for the others combinations of time and space. The spatial configuration adopted is shown in Table 2, where the length of the elements per stretch is in meters.

[Table 2]: Spatial discretization.

Stretch M1 M2 M3 M4 M5 M6 M7 M81 0,5 1 2 3 1 1 2 42 0,5 1 2 3 10,5 63 63 633 0,5 1 2 3 1 1 2 44 0,5 1 2 3 7 7 7 75 0,5 1 2 3 1 1 2 46 0,5 1 2 3 9,5 18 18 18

Total of Elements

510 255 128 85 95 83 45 26


All simulations were performed on a notebook type computer with a dual-core processor, CPU 1.6 GHz / 2.6 GHz and 4GB of RAM. The variation of the processing time was 5:1 with respect to duplication of the element length and 1:2 doubling the time step. Therefore, reducing the length of the element by half and doubling the time step resulted in an approximate 10 times reduction in processing time.

6. RESULTS

The present comparative study performed was based on a existing measurements of a sudden load rejection of 780,5 MW, with full opening of the distributor and gross head of 120.2 mWc realized at commissioning tests of the U18A.

Considering the losses in the generator, the rejected power in the turbine shaft was estimated in 791,5 MW, corresponding to flow of 770 m3/s and net head of 118.4 mWc in accordance with the hill curve of the turbine. The maximum pressure P and speed rotation N measured for this condition were 166.4 mWc and 141.8 rpm, corresponding an elevation of 29,4% and 41,7% for these parameters, respectively.

Although 32 different space-time meshes have been simulated, the main results obtained are enough represented at the six cases indicated in Table 3 with relation to the time simulation, percentage relative error to the maximum measured value of the overpressure ΔP and overspeed ΔN and pressure perturbations due to the return of the acoustics waves. Because of this only these six cases are presented in this section. Some parameters of the simulation are also indicated. It was used a constant friction coefficient of 0.025 and a simulated time of the process of 30s for all studied cases. For the case of mesh M6.T1 with non-uniform spatial elements, the Courant value is referred to the smaller element. For the others cases indicated in Table 3, the spatial elements are uniforms.

The time evolution of the pressure obtained by the methods RKM and MOC for the cases indicated in Table 3 are shown in Fig. 11.a to Fig. 11.f, superimposed on a subsampling in 20 Hz of the measured values. The maximum values for overpressure ∆P and overspeed ∆N by both methods are in general equivalents and consistent to the values measured. However, the relative error for the MOC increases sharply for meshes with nonuniform spatial elements and slightly for the RKM with increasing time step, though this is not evident in the cases of Table 3. With respect to processing time, MOC always presents low values for even refined meshes, unlike of RKM that has highest processing time as well as a greater increase of this how much the space-time mesh is finer. However similar results by both methods can be obtained choosing adequately

the mesh. For example, similar results to the MOC-M4.T1 (1s) can be obtained at RKM-M1.T4 (77,5h) or RKM-M6.T1 (143s). None of the methods presents numerical instability, signaling that the proposed equating with a variable diameter for the MOC was successful.

Both methods also captured the reduction of the pressure immediately after the start of the transient. This slight reduction in pressure before its rising can be attributed to the inertia of the flow, providing an increase in speed energy at the beginning of the closure of the distributor. With relation the pressure oscillation due overlap of positive and negative waves in the pressure, whose theoretical period is T = 4L a = 1.061s or frequency of 1.36 Hz, this was very dependent of the space-time discretization, reaching to be severely masked in RKM for some cases, e. g., RKM-M1.T1.

So the coarser non-uniform mesh M6.T1 presented better results than the finer uniform mesh M1.T1. The celerity of the waves was obtained considering the elasticity of the tubing and of the fluid. The actual values found for the period of the pressure oscillations was 0.89s at the numerical simulations and 0.77s at field test. Refining of the modeling of the distributor and consideration of viscoelastic effects could improve the adherence to this parameter.

The simulated overspeed curve of Fig. 12.a may be considered quite equivalent for both methods and cases, except for those where the relative error of the pressure is abnormal, as in case of MOC-M6.T1. A higher value of the simulated rotation and the time lag between measured and simulated values can be attributed mainly to the lack of updating the turbine efficiency with the variation of its rotation, reducing the dissipative braking forces. This deficiency could be corrected introducing at the numerical routine the variation in efficiency with the turbine speed during the hydraulic transient after the load rejection. For this purpose, the use of the characteristic curves of the turbine in its dimensionless representation (polar) shown on [2], [3] and [4] is recommended.

The results of the simulations with variation in the closing time law are shown in Fig. 12.b, in which is evidenced the possibility of reducing approximately 7% in overspeed after a full load rejection, keeping the nominal limit of 30% in overpressure. At the graph of this figure y-axis is non-dimensional variation of the overpressure and overspeed relative the rated (100% ) level for the pressure and rotation parameters. Therefore an elevation of 30% corresponds to a level of 130% in the graph curve. So, reducing the current closing time of 14s corresponding the maximum opening (full gate) to about 10.9s would result in an estimated overspeed value of 137.1%, that is around 7.1% below the estimated 144.0% for the current closing time.

[Table 3]: Spatial discretization.

Method/Mesh l [m] n a [m/s] Δt [s] Cr Simulation time P [mWc] N [rpm] ΔP [%] ΔN [%]

Runge-Kutta – M6.T1 252 83 950 1.05e-3 1 143 [s] 166,9 144,0 0.30 1,55

Runge-Kutta – M1.T1 252 510 950 5.26e-4 1 4.98 [h] 166,4 144,1 0.00 1.62

Runge-Kutta – M1.T4 252 510 950 2.63e-5 0,05 77.5 [h] 166,7 144,2 0.18 1.69

Characteristics – M4.T1 252 85 950 3.10e-3 1 1.0 [s] 167,0 144,0 0.36 1.55

Characteristics – M1.T1 252 510 950 5.26e-4 1 15.9 [s] 167,9 144,2 0.90 1.69

Characteristics – M6.T1 252 83 950 1.05e-3 1 1.3 [s] 142,2 139,7 -14.5 -1.48


[Figure 11: Pressure by Runge-Kutta method (a, b, c); Pressure by method of Characteristics (d, e, f).]

[Figure 12: a) Overspeed; b) Closing Time x Maximum Overpressure and Maximum Overspeed.]

To finalize this section the main observations about the capacity and performance of the methods RKM and MOC to estimate numerically the hydraulic transient at penstock after a sudden load rejection of a hydraulic machine are summarized in Table 4.

[Table 4]: Main observations of the results.

Runge-Kutta – RKM Method of Characterists - MOC

Small relative error for all meshes used

Small relative error only for uniform spatial discretizing

Excellent accuracy in the stationary part of the pressure to discretizing with uniform elements or nonuniforms

Excellent accuracy in the stationary and oscillatory parts of the pressure to discretizations with unitary Courant and uniform spatial elements

The representation of the oscillatory part of the pressure due to the return of the waves depends severely on the time step to avoid masking

The representation of the oscillatory part of the pressure due to the return of the waves is satisfactory to all used space-time meshes

Greater simulation time Smaller simulation timeThe damping of the oscillations at the end of the closing is best represented

The damping of the pressure oscillations at the end of the closing is unsatisfactorily represented

Runge-Kutta – RKM Method of Characterists - MOC

More complex numerically to be implemented due to the construction of the matrices

Easier to be implemented numerically

Non presented instability for any of used space-time meshes

Requires unitary Courant to avoid dispersion and numerical instability

7. CONCLUSION

The solution of the transient flow in a load rejection at a hydraulic turbine by Runge-Kutta method presents satisfactory accuracy and capacity to enough reproduces the phenomenon in an attractive numerical processing time for a suitable mesh. So, about these aspects, it configures as an alternative to the Method of Characteristics, with points advantageous and others disadvantaged.

The equating used at the MOC allowed apply it for the pipeline with variable diameter but without the occurrence of numerical instability.

The overpressure and overspeed for a given rejection are directly affected by the distributor closing time law and the numerical simulation of these phenomena in hydraulic transients allows assessing in the design phase the closing time law and rotational inertia required to meet the contracted values for the same.

The application of computational simulation of hydraulic transient and overspeed in existing generating units allows evaluating the potential for optimization of these parameters by changing the closing time law, with benefits for their operational safety and service life and avoiding perform such study in an experimental way.

8. NOMENCLATURE

Term Symbol UnitCross section of pipe A m2

Distributor free static area Aw m2

Distributor free dynamic area At m2

Capacitance C m3

Número de Courant Cr -Diameter D mPiezometric head H mcaNet head Hn mcaMoment of inertia J kg m2

Inductance L s2/m2

Rotation N rpmPower P WDischarge Q m3/sResistance R sVane opening S mTorque T NmNumber of vanes Z -Wave celerity a m/sVane height b mFriction factor f -Acceleration of gravity g m/s2

Length l mNumber of elements n -Time t SLongitudinal position X MTurbine efficiency Η -Specific weight of water g N/m3

Time step Δt sLenght of spatial elements Δx m


9. ACKNOWLEDGMENTS

The authors would like to express their sincere gratitude to the ITAIPU BINACIONAL for providing the data and information necessary and to the Center for Advanced Studies on Safety of Dams – CEASB belonging to the Foundation Technological Park Itaipu – FPTI for the support to this work.

“The author thanks the International Electrotechnical Commission (IEC) for permission to reproduce Information from its International Standards. All such extracts are copyright of IEC, Geneva, Switzerland. All rights reserved.

Further information on the IEC is available from www.iec.ch. IEC has no responsibility for the placement and context in which the extracts and contents are reproduced by the author, nor is IEC in any way responsible for the other content or accuracy therein”

10. REFERENCES

[1] IEC 60193. Hydraulic turbines, storage pumps and pump-turbines – Model acceptance tests. International Eletrotechnical Commision, 1999.

[2] Chaudry, M. H. Applied Hydraulic Transients. Springer, 3rd edition, 2014.

[3] Streeter, V.; Wylie, E. Fluid Transients. McGraw-Hill Inc, 1978.

[4] Nicolet, C. Hydroacoustic Modelling And Numerical Simulation Of Unsteady Operation Of Hydroelectric Systems. PhD thesis 3751, EPFL, Lausanne, Switzerland, 2007.

[5] Sarra, S. A. The Method of Characteristics with applications to Conservation Laws. Journal of Online Mathematics and its Applications, Vol. 3, 2003.

[6] Urroz, G. E. Hydraulic pipe transients by the the method of characteristics. 20 Mar. 2015. <http://twixar.me/0H5>, 2005.

[7] Tullis, J. P. Hydraulics of Pipelines – Pumps, Valves, Cavitation, Transients. John Wiley & Sons. New York, 1989.

[8] ITAIPU. Itaipu Hydroelectric Project: Engineering Features. Itaipu Binacional, Curitiba – PR, 1994.

[9] Iliev, V; Popvski, P; Markov, Z. Transient Phenomena Analysis in Hydroelectric Power Plants at Off-Design Operating Conditions. International Journal of Engineering Research and Applications. Vol. 2 (6), 2012.


FEASIBILITY ASSESSMENT FOR DEPLOYMENT OF MINI HYDROPOWER

PLANT IN CONSOLIDATED RESERVOIR1Mendes, Thiago Augusto; 2Savas, Tuna Kan

1Doutorando em Geotecnia e Mestre em Rec. Hídricos, tel. 55 62 99631-2248, e-mail: [email protected], Professor Instituto Federal de Educacao Ciencia e Tecnologia de Goias, Civil Engineering, Av. Universitária Vereador Vagner da Silva Ferreira, Parque Itatiaia, Aparecida de Goiânia, 74968-755, Brazil 2Pontifícia Universidade Católica de Goiás, PUC GOIÁS, Brasil. [email protected]

ABSTRACT

With increasing energy demand in Brazil, preferably renewables, investment in hydroelectric generating plants has advanced. In this way presents opportunities for investment in the deployment of hydropower generating plants in reservoirs already consolidated. Given this scenario, we present an analysis of economic and environmental viability for deployment of Mini Hydropower Plant Poço da Cruz in dam engineer Francisco Saboia, Poço da Cruz, Ibimirim municipality, state of Pernambuco. This analysis will take into account the historical water reservoir in relation to energy capacity, providing investment data for Mini Hydropower Plant (MHP). At the end are three scenarios prepared based on different stages of the project. At the end are three cash flow scenarios of implementation and operation of Mini Hydropower Plant, where we determined the Internal Rate of Return (IRR) and payback on investment.

KEYWORDS: Viability, dams, IRR, payback.

1. INTRODUCTION

Seeking to capture alternative revenues to fund activities such as monitoring, security and maintenance of reservoirs, the National Departament of Development Against Droughts in Brazil (DNOCS), promoted public bidding to explore Mini and Small Hydropower Plants in public reservoirs located in the brazilian northeast region (DNOCS, 2009). It is defended in these reservoirs the multiple use of water, this being one of the foundations of the National Policy on Water Resources (Law 9,433/1997). Multiple use of water resources allows their preservation through streamlining and planning of its use, thereby ensuring economic and social benefits for all users.

The public bidding was performed in november, 2009. The winner of the concession contract for lots 1 and 2 that represents the totality of the contract was Rodrigo Pedroso Engenharia, currently, JMP Energy based in the city of Goiania, state of Goias. In its total, National Departament of Development Against Droughts in Brazil reads on the contract 36.49 MW of installed power. This potential, defined on the concession agreement by the National Departament of Development Against Droughts in Brazil, can incur changes, according to further studies to be performed on each of the reservoirs. The Table 1 describes the reservoir that integrates the concession agreement.

As indicated on Table 1 the reservoir that is part of interest of this study is the Poço da Cruz, in the Moxotó river, located in the county of Ibimirim, state of Pernambuco. Initially it was planned installed capacity of 1.00 MW.

[Table 1]: Reservoirs members of the concession agreement.

RESERVOIR CITY STATEPOTENTIAL

(MW)

Anagé Anagé Bahia 1.00

Armando Ribeiro ItajáRio Grande do Norte

6.01

Banabuiú Banabuiú Ceará 3.80

Boqueirão Boqueirão Paraíba 1.00

RESERVOIR CITY STATEPOTENTIAL

(MW)

Castanhão Alto Santo Ceará 12.30

Figueiredo Iracema Ceará 1.00

Flores Joselândia Maranhão 5.28

Jucazinho Cumaru Pernambuco 1.00

Orós Orós Ceará 3.10

Poço da Cruz Ibimirim Pernambuco 1.00

Taquara Cariré Ceará 1.00

Source: (National Departament of Development Against Droughts in Brazil, 2012).

Within this context, the study seeks to analyze economic and environmental viability of Mini Hydropower Plant Poço da Cruz, seeking to optimize the principle of multiple use of water resources and even contribute for other purposes such as, per example: irrigation, cattle raising and public water supply. The preparation was based on data provided by the licensee, JMP Energy and through studies drawn from data in the region Mini Hydropower Plant (MHP). Several reservoirs in the country built with public supply, irrigation, among others, have potential for hydroeletric development was not implemented.

In the case of reservoirs already built, the analysis of hydropower potential takes into consideration the purpose of the reservoir. Other uses cannot interfere with this purpose. Therefore, to verify that the implementation of the MHP is viable, initially should be aware of the uses of upstream and downstream of the reservoir and the interested party must know whether the use was predicted in the execution of the Project of the dam (National Water Agency in Brazil, 2012).

1.1 Regulation of the sector

The Mini Hydropower Plant (MHP) is defined by the National Electric Energy Agency in Brazil (ANEEL, 2012), as the reutilization of the hydropower potential for power generation, with an installed capacity of up to 3,00 MW (Law nº 13,360/2016). The MHP independent from the concession or authorization in accordance with the Law 9,074/1995 and



should only be registered at National Electric Energy Agency in Brazil, for its regulation.

Brazil has in total 4,724 power generation projects in operation, generating 162,950,472 kW. Among these, 617 are the MHP type, generating 558,544 kW of power. This number represents about 0.34 % of the power granted in the country.

1.2 Feasibility Analysis

The feasibility of power generation projects is linked to some fundamental characteristics. Are important and relevant to its viability: the land, technology, workforce, customers and licenses to be obtained. When this set becomes feasible and available, and when you add all of these stakeholders you have a social, financial and environmental logic, ie, the business is viable (B-REED, 2012).

Determine the viability of a business does not guarantee that it will receive funding or will be implemented, many other factors contribute in this issue, but this will pave the way for the business that presents itself to sensible people participating technically and financially on it (B-REED, 2012).

To start the design of a Mini Hydropower Plant (MHP) is necessary to conduct an economic feasibility study and, therefore, must estimate the cost and benefit of MHP. It is important that this analysis can compare the various possibilities of arrangement and sizing of components (QUEIROZ, 2010).

Queiroz (2010) relates, in its feasibility study, power variation, energy generated, cost and benefit to define the feasibility of MHP. It is presented two developments of economic analysis, which allowed the analysis of various possibilities of arrangements, of available flow and sizing of the generating group. Based on values of cost of implementation and operation from 1998, performed the due update, the study by Queiroz (2010), was able to determine the time of return on the investment, considering an average energy price over a given time. Starting from the initial development of his study he applied this methodology in a real case and analyzed the financial return that the insertion of a MHP, in a place where they already had two potentials installed.

Investment in Mini Hydropower Plant (MHP) and Small Hydropower Plant (SHP) has attracted many entrepreneurs. This reality is linked mainly to lower investment costs compared to hydroelectric power plants and lower construction period, another important factor is linked to less bureaucracy of the regulatory system both electric and environmentally for this sized enterprise (THOMÉ, 2007).

The initial investment is the largest portion of the cost of MHP. Involve the initial development costs, project, studies, engineering, the implementation of environmental programs, acquisition of materials and equipment and execution of the work. After the operation the cost becomes only the maintenance and operation of MHP (QUEIROZ, 2010).

Gouvêa and Baggio (2012) conducted a study to define solutions that should be adopted for economic feasibility of SHP. Through the study of a real case of implementing a SHP of 4.00 MW, in 24 months, they estimated all spending and investment applied in the SHP. In general, the total budget of a SHP can be divided into four parts: land acquisition, Engineering, Procurement and Construction (EPC), administration costs and engineering and finally environmental costs.

Initially, the first solution provided by Gouvêa and Baggio (2012) to reduce costs is to use equipment usually simpler in the plant. Security and maintenance are also important points to be developed in order to seek the reduction of costs of the project. Continuing, Gouvêa and Baggio (2012) conducted financial

simulations for a total period of 30 years. With this simulation, it was possible to demonstrate the Income Statement for the project. The Internal Rate of Return (IRR) was 16.89 % p.y.

The main result of Gouvêa and Baggio’s study (2012), concerns the funding held by Brazilian National Development Bank. The result of the simulations demonstrates that the increased participation of Brazilian National Development Bank to 90% in investments SHP and that keeping interest rates similar to the 70 %, significantly improves the attractiveness of the projects and, consequently, investments in the building of SHP. But it is still seen as a negative point the steady rise in prices of construction inputs, electromechanical equipment and skilled labor reconciled with the high interest rates and low sales price of the energy. These variables minimize the attractiveness of investment, which end up minimizing the rate of return on investment.

After the conducted researches, it was revealed that there is little information regarding the implementation of SHP or MHP in consolidated reservoirs. The fact that the reservoir is already built, guarantees the entrepreneur a lower cost of deployment, because as stated earlier, the main costs are related to projects and environmental programs, executive project and construction of the dam. Thus, the entrepreneur generally should only be concerned with studies of the basic design, environmental permitting (usually with few constraints), executive design of the powerhouse and finally the construction and the acquisition and installation of electromechanical equipment, all requiring verification and evaluation viability.

1.3 Hydrological Studies

The hydroelectric potential of the Mini Hydropower Plant Poço da Cruz, was not defined by study of hydropower inventory because the reservoir was not initially built for this purpose. The definition of the hydroelectric potential was performed through the hydrologic study using data from the gauged stations in the region, where it was calculated the minimum, average and maximum flow fluent reservoir. The hydropower concessionaire developed the studies from these data.

Initial studies of the concessionaire predicted flow of 3.40 m³ s-1 available for power generation, however this value was questioned by the National Water Agency in Brazil, as presented in the next chapter. The flow rate indicated by the concessionaire and the National Water Agency in Brazil was verified in this present study through the studies of the tank model for the Poço da Cruz’s reservoir.

2. METHODOLOGY

In order to present the environmental feasibility of Mini Hydropower Plant (MHP) Poço da Cruz initially delimited the basin where the MHP is inserted, it was then collected rainfall data, historical stream flow of the reservoir of Francisco Sabóia and presented the operating regime of the MHP. The economic feasibility was based on the data provided by the company itself and the analysis was made from three simulations with the data provided, each of which addressed different phases of the project: planned scenario, scenario with environmental restrictions and current scenario.

2.1 Survey of the River Basin Moxotó

The basin of the Moxotó river is situated, mostly in the state of Pernambuco, extending in its southeastern portion to the state of Alagoas and to the São Francisco river. The basin is located between 07º 52' 21 " and 09º 19' 03" south latitude and between 36º 57' 49" and 38º 14' 41" west longitude.


The Figure 1 shows the delineation of the basin of the Moxotó river performed by Oliveira et al. (2009), in his study and assessment on land cover in the watershed.

[Figure 1: Location of river basin Moxotó. Source: (OLIVEIRA et al., 2009).]

2.2 Drainage Area

The drainage area of the reservoir Poço da Cruz was delimited using the GIS software, ArcGIS, version 9.3.

Initially we worked with planialtimetrics images of the region (Miranda, 2005). They are accurate images form the satellite Shuttle Radar Topography Mission usually called SRTM images. Through initial analysis it was seen that the basin occupies 4 images in total, so it was necessary to create a mosaic of images. Images are: SC-24-XA, XB-SC-24, SB-24, SB-24.

From the image generated by ArcGIS it was possible to start the work to define the drainage area of the reservoir Poço da Cruz. The software has a tool to extract the drainage network, where at the end all possible rivers, streams, or preferential pathways of water were raised. To define the drainage area were used the images provided by National Water Agency in Brazil from Ottobacias Level 5. The Ottobacias are areas of contribution of stretches of the river coded according to the method of Otto Pfafstetter for classifying basins in Brazil. Altogether the drainage area corresponds to 4,630.84 km².

2.3 Poço da Cruz reservoir

The Poço da Cruz reservoir is located in Ibimirim, State of Pernambuco. The beginning of the construction of the Eng Francisco Sabóia, or Poço da Cruz reservoir, was in 1957, and opened in 1959. Its main purpose is to supply the Irrigated Perimeter of the Moxotó River. Table 2 presents the technical of the Poço da Cruz reservoir.

[Table 2]: Technical specifications Poço da Cruz.

reservoir engineer Francisco SabóiaName Poço da CruzBasin state Moxotó river

GoalMainly irrigation of lands downstream of the valley, about 8,000 ha, fish farming, crop areas upstream.

State / City Pernambuco / IbimirimYear beginning construction 1937Year construction completion 1958Capacity (m³) 504,000,000.00Dead volume (m³) 75,600,000.00Quota threshold (m) 435.00Crest elevation (m) 437.50Hydraulic Basin (m²) 56,000,000.00

Source: (National Departament of Development Against Droughts in Brazil, 2012).

In August 2012, the Mini Hydropower Plant of Poço da Cruz through the Resolution No. 364 of August 20, 2012, received from the National Water Agency in Brazil, a response for the request to grant the right to use water resources.

The flow rate granted by the National Water Agency in Brazil is relatively lower than the predicted by the hydrological studies conducted by the concessionaire. This is one of the factors that directly influenced in the capacity factor of generation of the Mini Hydropower Plant of Poço da Cruz. The time "idle" of the Mini Hydropower Plant of Poço da Cruz drastically reduced its ability to generate energy or also called power factor, which is currently less than 22 % of the installed capacity.

2.4 Rainfall IndexThe survey of rainfall stations was based on the research

in HIDROWEB. The database is provided by National Water Agency in Brazil, through its website, where data from stations scattered throughout the country, can be accessed. In many cases National Water Agency in Brazil itself operates the rainfall stations, but in others, the operation can be performed by other agencies.

The rainfall stations analyzed are presented in Table 3 and Figure 2. As indicated, the whole nine stations were selected for the study. It was not possible to access the data of the other four stations mentioned: station 837008 (Brejo do Piore), station 837030 (Poço da Cruz), station 837047 (Ibimirim) and station 837056 (Poço da Cruz).

This can occur if the operator is not linked to National Water Agency in Brazil and so the information is not passed on to the same.

[Table 3]: List of rainfall stations.

CODE NAMESUB-

BASINSTATE CITY

RESPON-SIBLE

OPERA-TOR

LATITUDELONGI-TUDE

8370061 Poço da

Cruz49 PE IBIMIRIM SUDENE4 SUDENE4 08 30 00 S 37 44 00 W

837008Brejo do

Piore49 PE IBIMIRIM SUDENE4 SUDENE4

08 37 00 S

37 32 00 W

837025Ibimirim (Jeritaco)

49 PE IBIMIRIM DNOCS² DNOCS² 08 23 00 S 37 38 00 W

837028 Moxotó 49 PE IBIMIRIM DNOCS² DNOCS² 08 43 00 S 37 32 00 W

837030Poço da

Cruz49 PE IBIMIRIM DNOCS² DNOCS²

08 30 00 S

37 44 00 W

837047 Ibimirim 49 PE IBIMIRIM EMATER EMATER08 32 00 S

37 42 00 W

837056Poço da

Cruz49 PE IBIMIRIM ANA3 HOBECO

08 29 43 S

37 42 02 W

837010 Carualina 49 PE SERTÂNIA SDN SDN 08 18 00 S 37 34 58 W

837011 Custódia 49 PE CUSTÓDIA DNOCS² DNOCS² 08 05 60 S 37 38 60 W

837014Fazenda Caiçara

49 PE CUSTÓDIA SDN SDN 08 20 60 S 37 45 00 W

837016Fazenda Jacaré

49 PE FLORESTA SDN SDN 08 25 00 S 37 55 59 W

837032Rio da Barra

49 PE SERTÂNIA SDN SDN 08 09 00 S 37 28 59 W

837033Sertânia (Alagoa

de Baixo)49 PE SERTÂNIA DNOCS² DNOCS² 08 04 60 S 3716 00 W

where: This station corresponds to 837030 station and is not shown in Figure 2; 2DNOCS - National Departament of Development Against Droughts in Brazil; 3ANA - National Water Agency in Brazil; 4SUDENE - Northeast Development Superintendence in Brazil. Source: (HIDROWEB, 2013).


[Figure 2: Location of rainfall stations raised. Source: (GOOGLE EARTH, 2016).]

2.5 Tank Model

The model used to verify the monthly average of the streamflow was the Tank type. To calculate the monthly average of precipitation it was used the Multiquadric method. The Multiquadric method consists in determining the weighting coefficients that are used in interpolation, on the premise that the total area of rain over the basin may be the result of several quadric surfaces or kernel functions, each originating from a point at which the value of f(x, y) is known. Adjusting a surface that passes through all points known one can find the coefficients of each position to determine the rainfall precipitation at any point (BALASCIO, 2001; BARBALHO, 2012).

The Tank model is characterized by having a simple and easy structure to implement as well as being the most suitable for analysis of longer periods as the month. The structure of the Tank model for humid regions, consists of three tanks arranged vertically in series Figure 3.

The discharge of water in the first tank, through the two lateral outlets corresponds conceptually to the flow surface and the hypodermis. The water that flows in from the second tank through the outlet side is equivalent to the intermediate flow. The flow through the outlet side of the last tank corresponds to the basic flow or underground. So the total sum of all these side exits, corresponds to the river flow in the considered section (MENDES et al., 2007). For each tank, the lateral flow Q (output) is proportional to the height h of the water stored in the tank above the outlet side and it is expressed by Q = A.h, where A is the coefficient of the exit side calculated by the model.

[Figure 3: Scheme Tank model. Source: (MENDES et al., 2007).]

The information on the minimum value or base flow is useful for the planning of water use in drought periods. The Tank model makes possible to consider that the discharge is a result of the amount of water stored in the basin. That way, excess and lack of flow may be associated with the condition of water storage (moisture of the hydrografic basin) (THOMÉ, 2007).

2.6 Economic Viabilitty Analysis

The early assessment of the implementation of the project is the evaluation of the costs until the current time. The data was provided by JMP Energy Ltda, through spreadsheets, showing actual expenses with MHP and payments for the purchase and sales of energy. For being a reservoir that is consolidated, in other words, the work of the dam has been done and the reservoir is in operation, the project for the hydroeletric exploitation follows a less bureaucratic way on environmental issues and also in relation to other regulatory companies, such as National Electric Energy Agency in Brazil (ANEEL). Because of such factors, many expenses common to the implementation of hydropower plants do not need to be performed, for example, studies of hydroelectric inventory, land acquisition, environmental activities in the reservoir and engineering costs (executive project and construction of dam).

The costs that were analyzed refer to stranded costs (ba-sic design, topographic studies, permits, hydrological studies, among others), investment (management, consolidation of the basics on the project, civil executive project, electromechani-cal executive project, insurance and warranty, the civil works, equipment: electrical/automation/mechanical, turbine/genera-tor, hydro-mechanical equipment, substation/adaptor, assembly, unexpected expenses) and finally costs with operation/mainte-nance of the plant (actual data submitted by the company).

The company also allowed the access to revenue relating to energy sales. The sales began in the month of January of 2012. That same year, the sales did not occur in a steadily for, as some electromechanical problems happened and the data were nor consolidated. From the beginning of 2013 the operation of the plant was normalized, and every month since then, there is energy available for sale in the free market. The months in which the generation data were not consolidated, the company bought energy in the free market to meet its commitment to the trader. These data were also presented by the company, and at the end were assessed.

2.6.1. Viability Analysis

For economic viability analysis it was used spreadsheets in MS Excel provided by JMP Energy Ltda. It was used projections of cash flow of the company over a 35 years period of projection of the company awarded by DNOCS. The analysis took into account the scenario originally planned by the company, a scenario with environmental restrictions (factor of capacity reduced) and the real scenario of operation of the MHP.

In the first scenario the data and initial parameters were those used for the viability analysis prior to construction of the project, which means, the project data. In the second scenario presents data and parameters considering environmental constraints for the operation and functioning; at this moment the capacity factor of power generation is drastically reduced. Finally, the third scenario presents actual data and parameters of operation of the MHP considering losses with no power generation, maintenance expenses, among others. It was adopted averages in order to present the actual generation capacity of Mini Hydropower Plant from December 2011 to February 2016 (Table 4).


[Table 4]: Basic dates.

POWER AND

ENERGY1º SCENARIO

2º SCENARIO SCENARIO

3º SCENARIO

Power Installed

840 kW 840 kW 798 kW

Capacity factor

94.0% 22.0% 22.0%

Average energy

789.60kW

medium185

kW medium

médmédios176

kW medium

Energy firm

764.60kW

medium160

kW medium

151kW

medium

Source: Data provided by the JMP Energy, adapting it to the author.

3. RESULTS AND DISCUSSIONS

The data collected for economic viability study that were presented, refer to the operation of Mini Hydropower Plant (MHP), between December, 2011 to February , 2016, and all the information were given by the Financial Department of JMP Energy Ltda. Based on data provided by the company, three different scenarios were simulated in order to present the cash flow of each one.

3.1 Calculated Flow Rates from Tank Model

Once all the input data were obtained (average of monthly rainfall – Multiquadratic method, monthly average streamflow – Provided by the company and evapotranspiration – measured by Thorhwaite method) it can apply the method of rainfall-runoff Tank model and, from several simulations, obtain data of calibration model and a possible answer to the question of data discharges into the reservoir.

Figure 4 shows the annual average of rainfall calculated by Multiquadratic method in the basin of the reservoir Poço da Cruz. The method allows to acquire monthly average of rainfall, which were used in the Tank model.

[Figure 4: Average annual precipitation on the reservoir watershed Poço da Cruz a) perspective; b) designing.]

In the Tank model the data of rainfall stations that were used were from january 1963 to december 1984 (about 21 years). The parameters for the characterization of the basin found in the calibration process for the period of January 1963 to December 1984, were obtained from the Excel Solver tool, and are presented in Table 5. Figure 5 shows the visual comparison between observed and calculated values in this process.

[Table 5]: Parameters used in the Tank model (Figure 3) for reservoir Poço da Cruz in the period Jan/63 - Dec/84.

h1 (mm)

h2 (mm)

h3 (mm)

a1 (mm)

a2 (mm)

a3 (mm)

b1 (mm)

b2 (mm)

607.64266 306.237 0.0 0.472707 0.583322 0.080961 0.318973 0.889312

Source: Developed by the authors.

[Figure 5: Flows calculated by the model Tank model. Source: Developed by the authors.]

The flow rate calculated by the Tank model did not adjust well to the observed discharge (provided by the company) using the objective functions commonly used (module and square of the difference). This can be explained by the unreliability of the observed discharged that was provided.

3.2 Analysis of Costs and Investments

Like was mentioned earlier, the JMP Energia Ltda provided all the data related to costs and investments for the implementation/refurbishment and operation of the MHP. The data were provided through spreadsheets, which contains all payments made by the company.

The information given in Table 6 consist primarily of the cost with civil structures, improvements (such as improved access and reform of the penstock) the purchase and electromechanical installation (turbines, generators, automation systems, among others), and the costs of the projects.

[Table 5]: Parameters used in the Tank model (Figure 3) for reservoir Poço da Cruz in the period Jan/63 - Dec/84.

DEPLOYMENT SPECIFICATION TOTAL (R$)

PROJECT Basic Project 97,047.06

CIVIL Retirement of Facilities 240,000.00

ELECTROMECHANICAL Equipment 275,965.30

TOTAL 2,544,769.45

Source: Developed by the authors.Table 7 shows the relationship of costs with the operation

and maintenance of the MHP. The vendor data were not presented for confidentiality reasons, so, the table presents just the sum of the amounts paid and the purpose of payment.


[Table 7]: General costs of maintenance and operation of MHP.

MAINTENANCE AND OPERATION TOTAL (R$)

Class Association R$ 11,230.50

Purchase Of Materials And Other Electromechanical R$ 61,116.14

Energy Consumption And Network Access Transmission R$ 83,876.16

Administrative Costs / Office R$ 76,306.49

Procedural Costs R$ 14,301.87

Expenses Related To Maintenance / Operation R$ 213,874.23

Attorneys Fees R$ 1,995.30

Accounting Fees R$ 35,258.77

Renewal Of Operating License R$ 10,811.34

Salary And Wages Operator R$ 55,728.00

Guarantee Insurance R$ 217,087.67

Outsourced Corporate R$ 75,497.51

Fees, Taxes And Contributions R$ 109,406.70

Contribution /Payment NATIONAL DEPARTAMENT OF DEVELOPMENT AGAINST DROUGHTS IN BRAZIL

R$ 54,144.02

TOTAL R$ 1,020,634.70


Since it was a MHP already in operation, it was possible to gain access to revenue relating to sale of energy generated. The data are presented in Table 8. It can be observed that the sale started to occur from january 2012, with the energy generated in december 2011.

[Table 8]: Sale of energy.

RECEIVING (YEAR) TOTAL (R$)

2012 86,558.00

2013 266,040.00

2014 628,056.00

2015 436,076.00

2016 31,848.00

TOTAL 1,448,580.00


In some months of 2012, there was no power generation due to mechanical problems, so there was no energy generated for sale. To meet the energy supply contract with the trader, the Mini Hydropower Plant Poço da Cruz had the need to buy electricity on the open market and provide the trader. The amounts referring to this purchase are described in Table 9.

[Table 9]: Purchase Energy.

TRADERSPURCHASE

DATADATE OF

PURCHASETOTAL (R$)

Trader A Octuber/2012 11/14/2012 88,908

Trader B November/2012 12/12/2012 124,135

Trader B December/2012 01/14/2013 92,795

TOTAL 305,839


3.3. Initial Considerations for Viability Analysis

For Mini Hydropower Plant Poço da Cruz the following parameters were considered in the elaboration of Cash Flow:• investment for the construction of the MHP in the amount

approximate R$ 2,500,000.00;• construction term of MHP in 11 months, starting in January

of 2011;• annual maintenance cost, R$ 7.00/MWh, resulting in

approximately R$ 50,602.50, adjusted 4.5 % in 2013;• the selling price of energy was adjusted by 4.5 % per year;• operation started December 2011;• concession period of 35 years.

Other data used to calculate the cash flow suffer change based on the simulation model, as follow:• The average net of energy production: o 1º. Scenario: 6,697.896 MWh annual trading o 2º. Scenario: 1,401.600 MWh annual trading o 3º. Scenario: 1,322.760 MWh annual trading• Initial sale price of energy: o 1º. Scenario: R$ 140.00/MWh o 2º. Scenario: R$ 200.00/MWh o 3º. Scenario: R$ 225.70/MWh

3.4. TIR and Investor’s Payback

As presented on Table 10 the 1º. scenario, the internal rate of return to the shareholders was 29.14 % per year. The simple payback (return on capital invested) was calculated over 4.79 years. The 2º. scenario shows that the internal rate of return to the shareholders was 9.04 % per year. The simple payback (return on capital invested) was calculated over 12.11 years. The 3º. scenario shows that the internal rate of return to the shareholders was 8.72 % per year. The simple payback (return on capital invested) was calculated over 12.43 years.

[Table 8]: Sale of energy.

PROJECT: POÇO DA CRUZ

SIMULATION 1º SCENARIO 2º SCENARIO 3º SCENARIO

POWERS AND ENERGIES

Installed capacity:

840 kW 840 kW 798 kW

Capacity factor: 94.00 % 22.00 % 22.00 %

Energy firm: 764.6kW

medium160.0

kW medium

151.0kW

medium

EXPENSES AND TAXES IN OPERATION

Operation and maintenance:

51,700.00 R$/year 51,700.00 R$/year 50,602.50 R$/year

Amount of grant:

4.00 % 4.00 % 4.00 %

Total tax burden (no ir):

4.30 % 4.30 % 4.30 %

Income tax: 25.00 % 25.00 % 25.00 %

EXPENSES IN DEPLOYMENT

Depreciable cost:

2,634,509.90 R$ 2,634,509.90 R$ 2,634,509.00 R$

RELEVANT DATA

Investment average:

3,136.32 R$/kW 3,136.32 R$/kW 3,301.39 R$/kW

Participation of the

entrepreneur100.00 % 100.00 % 100.00 %

Value of disbursements

(equity):2,500,000.00 R$ 2,500,000.00 R$ 2,500,000.00 R$


PROJECT: POÇO DA CRUZ

SIMULATION 1º SCENARIO 2º SCENARIO 3º SCENARIO

Rate of energy firm:

140.00 R$/MW 200.00 R$/MW 250.00 R$/MWh

Period of exploration:

35 year 35 year 35 year

Period return: 4.79 year 12.11 year 12.43 year

Internal rate of return:

29.14% 9.04% 8.72%


4. CONCLUSIONS

The purpose of this study was clearly satisfied after the data presented in Table 10 The difference, at least troubling that occurs with what is designed to happen and what usually happens over the operation of the Mini Hydropower Plant (MHP) is a decisive factor in the viability of the activity.

The importance of developing a good and serious study on hydropower, is very clear considering these results. Studies of the outflow available for power generation should be well structured to continue the viability study for the constructions of hydroelectric projects in consolidated reservoirs. This fact is evidenced by the results of the outflow calculated and adjusted by the model of Tank Model, that indicated low pick flow rates that were observed and average flow rates higher than observed.

As mentioned in the beginning of our study, perceiving the multiple uses that already occur in the reservoir is not an option, it is a decisive factor for the decision making and even allow the evaluation of real capacity for power generation in the reservoir. With the participation of the community combined with public management the outcome can be positive because it is no easy task reconciling all uses of the reservoir.

It is not possible to reverse the situation of Mini Hydropower Plant Poço da Cruz, the accumulated loss in the operation can be used as learning experience by the entrepreneur for other projects that are being developed through the Concession Agreement with the National Departament of Development Against Droughts in Brazil (DNOCS). Possible errors can be assessed and avoided. The expected profit and the return time can be compensated after the implementation of others already planned.

5. BIBLIOGRAPHY

ANA - AGÊNCIA NACIONAL DE ÁGUAS. Hidroweb – Sistemas de Informações Hidrológicas. Available at: <http://hidroweb.ana.gov.br>. Accessed: February, 2007.

_________. Resolução n° 364/2012. Dispõem sobre a Outorga da Central Geradora Hidrelétrica Poço da Cruz. Brasília, 08/20/2012.

ANEEL – BRAZILIAN ELETRICITY REGULATORY AGENCY. Atlas of Electric Power in Brazil: Hydraulic Energy. 3rd Edition. Brasília.

_________. Resolução n° 482/2012. Estabelece as condições gerais para o acesso de microgeração e minigeração distribuída aos sistemas de distribuição de energia elétrica, o sistema de compensação de energia elétrica. Brasília, DF, 17/04/2012.

_________. BIG – Generation Information Bank. Available at: <http://www.aneel.gov.br/aplicacoes/capacidadebrasil/capacidadebrasil.cfm> Accessed: February, 2013.

_________. Guide to the Small Hydroelectric Power Plant Entrepreneur. 1st edition. Brasília, 2003.

APAC - PERNAMBUCAN AGENCY OF WATERS AND CLIMATE. Information from the Moxotó River Basin. Available at: <http://www.apac.pe.gov.br/>. Accessed November 2012.

BALASCIO, C. C. Multiquadric Equations and Optimal Areal Rainfall Estimation, Journal of Hydrologic Engineering, v. 6(6): p. 498-505, 2001.

BARBALHO, F. D. Method for the determination of the area reduction factor in urban basins. Dissertation (master's degree) - Federal University of Goiás, Stricto Sensu Post-Graduation Program in Environmental Engineering, 2012.

BRAZIL. Law 9074/1995 - Establishes norms for granting and extensions of concessions and permissions of public services and makes other provisions. Brasília, DF.

_______. Lei 9433/2012 -Establishes the National Water Resources Policy, creates the National System for Water Resources Management. Brasília, Federal District.

B-REED – Development of Rural Energy Companies in Brazil. Feasibility Analysis. Available at: <http://www.b-reed.org/> Accessed: December, 2012.

CERPCH - NATIONAL REFERENCE CENTER IN SMALL HYDROELECTRIC POWER PLANTS. Available at: <http://www.cerpch.unifei.edu.br/>. Accessed: August and September, 2012.

DNOCS - NATIONAL DEPARTAMENT OF DEVELOPMENT AGAINST DROUGHTS IN BRAZIL. Concession contract n° 001/2009. Fortaleza, 2009.

_________. National Departament of Development Against Droughts in Brazil promotes Competition to produce energy in its reservoirs. Available in <http://www.dnocs.gov.br/php/comunicacao/tempo_real.php>, Fortaleza, November 6, 2009. Accessed: October, 2012.

_________. Technical File of Reservoirs. Available at: <http://www.dnocs.gov.br/php/canais/recursos_hidricos/>. Accessed;: August and September, 2012.

GOUVÊA, F. F.; BAGGIO, F. A. V. Solutions for Small Hydro Power Plants. In: Magazine PCH Notícias & SHP NEWS. Itajubá: CERPCH, n. 55, 2012, p. 20-25.

MENDES, T. A.; VIEIRA, M. E. A.; FRANCO, C.; VILELA, L. F.; FORMIGA, K. T. M.; BARBALHO, F. D. Application of the Tank Model of the Hydrographic Basin Modeling of Goiás. In: Anais XVII Brazilian Symposium on Water Resourcess – ABRH, SÃO PAULO – SP, 2007.

MIRANDA, E. E. de; (Coord.). Brazil in Relief. Campinas: Embrapa Satellite Monitoring, 2005. Available at: <http://www.relevobr.cnpm.embrapa.br>. Access: March, 2013.

OLIVEIRA, T. H.; GALVICIO, J. D.; SILVA, J. S; SILVA, C. A. V.; SANTIAGO, M. M.; MENEZES, J. B.; SILVA, H. A.; PIMENTEL, R. M. M. Evaluation of Vegetation and Albedo Coverage of the Moxotó River Basin with Images of the Landsat Satellite 5. In: Anais XIV Brazilian Symposium on Remote Sensing. Natal: INPE, April 25-30, 2009, p.2865-2872.

QUEIROZ, G. B. R. Economic viability analysis of hydroelectric generating plants. UNB, Brasília. Graduation Work. September, 2010.

THOMÉ, A. D. Avaliação dos Custos de Construção de Pequenas Centrais Hidrelétricas. Revista PCH Notícias & SHP NEWS. Itajubá: CERPCH, n. 35, 2007, p. 14-19.


STRATEGIC ENVIRONMENTAL ASSESSMENT – SEA OF THE HYDROELECTRIC GENERATION

PROGRAM OF MINAS GERAIS – HGPMG AS AN ENVIRONMENTAL MANAGEMENT INSTRUMENT

1Filho,Wilson Pereira Barbosa; 2Silva, Lívia Maria Leite da; 3Costa, Antonella Lombardi; 4Arantes, Irene Albernaz; 5Silva, Nathan Vinícius Martins da; 6Oliveira, Karina Aleixo Benetti de

1Civil Engineer at PUC Minas, Lawyer at University Salgado de Oliveira, MSc. in Environmental Management and Audit at Universidad Europea del Atlántico, PhD student of Program Nuclear Science and Techniques of Department of Nuclear Engineering at UFMG. Environmental Analyst of State Foundation of the Environment (Fundação Estadual do Meio Ambiente – FEAM). Professor of Energy Engineering degree course at PUC Minas. Lattes resume: http://lattes.cnpq.br/4241912943857821.2Energy engineer and master in Electrical Engineer at Pontifícia Universidade Católica de Minas Gerais. Researcher at State Foundation of the Environment (Fundação Estadual do Meio Ambiente – FEAM). Lattes resume: http://lattes.cnpq.br/6661724494856451 3Physics (Bachelor) at UFMG, MSc Technical Sciences Nucleares at UFMG, PhD in Nuclear Safety and Industrial at University Pisa, Itália. PhD Department of Nuclear Engineering at UFMG. Adjunt Professor and Researcher at the Department of Nuclear Engineering UFMG. Lattes resume: http://lattes.cnpq.br/0382135664206404.4Irene is currently the Director of Quality Management and Environmental Monitoring for the State Foundation for the Environment in Minas Gerais (FEAM). Irene’s commitment to achieving high standards during her academic pursuits which included receiving the “très honorable” citation for her doctoral thesis in Chemical Analysis from the French Government is translated to those that she now leads at FEAM. Lattes resume: http://lattes.cnpq.br/61825336716739905Environmental Engineering student at Centro Universitário Newton Paiva. Intern at State Foundation of the Environment (Fundação Estadual do Meio Ambiente – FEAM). Lattes resume: http://lattes.cnpq.br/9519876602254143 6Energy Engineering student at PUC Minas. Intern at State Foundation of the Environment (FEAM).

ABSTRACT

The Strategic Environmental Assessment – SEA, as an environmental management instrument, refers to the consequences of the policies, plans and programs (PPPs), usually within the scope of governmental initiatives, despite the fact that it can also be used in private organizations. It also allows the compatibility analyse of the PPP that is being studied comparing with others governmental PPPs (horizontal articulation). The SEA of the Minas Gerais Hydroelectric Generation Program (MGHGP) was organized in three big steps that were divided in six consecutives blocks of analysis, each one with a set of interdependent activities to be accomplished and the product to be generated. The study was entirely based in secondary data, thus, the results were associated to the availability and spatiality of the acquired information. The entire work was done considering the 175 hydroelectric plants (operation, concession and under construction), the 380 plants envisaged by the Minas Gerais Hydroelectric Generation Program (MGHGP), eight hydrographic basins from the territory of Minas Gerais, and 34 Water Resources Planning and Management – WRPMs. This article aims to discuss the obtained results and evaluate possible projections. it was evidenced the need to obtain the greatest possible expansion of the hydroelectric generating park in a sustainable way, what implies in the solution of equations that did not exist in the past, requiring the diversification of the Minas Gerais electrical matrix, the use of new technologies, the improvement of energy efficiency, as well as a holistic vision and technical capacity of the entities involved.

KEYWORDS: Knowledge network, environment, energetic planning.

1. INTRODUCTION

The strategic environmental assessment – SEA refers to the evaluation of the environmental consequences of policies, plans and programs (PPPs), generally within the scope of governmental initiatives, although it can also be applied in private organizations. It is a previous evaluation, which is equivalent, in a certain way, to the ones that areimplemented to projects, works or similar activities.

Nevertheless, the great SEA potential is in influencing the formulation of these PPPs by itself, as well as one of the main roles of the project’s environmental impact assessment is to formulate project alternatives that avoid or reduce adverse impacts or to make it possible to obtain better environmental gains. The SEA has been established as a planning tool due to two factors:

• The adverse socio-environmental impacts of PPPs and;• The inherent limitations of projects’ environmental impacts

assessment.

One of the reasons that have led to the international spread of the SEA is because it is flexible, which allows adapting it to distinct decision-making models. It has been already stated that there is not only one SEA model [1], that the SEA represents “a concept under multiple ways” [2], and that the SEA has the great advantage of being able to be adapted to nearly all ways and modalities of

planning in different decision contexts [1], instead of forcing the changing of a decision-making model, as it has happened with the Environmental Impact Assessments – EIA of projects.

Regardless the chosen SEA approach, it is necessary to recognize that there is substantial differences between a SEA and the project impacts assessment. Acoording to Woods [3], in one of the first studies about PPPs’ impact assessment, points to four major differences between the projects impacts assessment and the strategic assessment:

• Spatial delimitation precision: whereas the projects have a well established location, PPPs, excepting the land planning use, have less clear spatial delimitations;

• Detailing of actions: It is much superior in projects and it can be very indefinite in the case of policies;

• The time scale: the implementation period of a project is relatively short, whereas the duration of a policy or a plan can be very extended;

• The decision-making process and the involved institutions: while for projects there is a clear distinction between its proponent and the competent authority in approving it, PPPs are usually formulated and sanctioned by the same entity

The SEA would also enable the compatibility analysis of the PPP in question with other governmental PPPs (horizontal articulation). However, there is various practical difficulties, the following are highlighted:



• Sectoral planning and programs rarely are formulated in a clear way and without internal contradictions; and

• The already existing plans (which will supposedly be considered in the SEA) can be already incompatible among themselves.

Nevertheless, it is observed that there is an increasing interest in implementing the articulation between the SEA and other instruments applied in other decision-making levels and contexts, usually boosted by the expectancy that the previous implementation of a SEA can facilitate the approval and the licensing of projects. The possible advantages of the articulation are listed below:

• It allow the selection of potentially viable projects for posterior individual assessment;

• It foster the discussing and the “settlement” of strategic matters relative to the justification and the location of projects;

• It help the analysis of cumulative impacts (due to various similar projects or to different projects in the same region);

• It allow the implementation of the EIA of projects for local matters and to individual mitigations actions;

• It facilitate the approval of projects that are originated by PPPs or associated with them;

According to the Brazilian Ministry of the Environment [4], among the benefits that can be a result from the deployment of the SEA, some of the more important are:

• Comprehensive view of the environmental implications of the implementation of the governmental policies, plans and programs, whether they are relevant to the sectoral development or restricted to a specific region;

• The assurance that the environmental subjects will be properly handled;

• Facilitation of the connection of well structured environmental actions;

• Process of development of policies and environmentally sustainable and integrated planning;

• Anticipation of the probable impacts of necessary actions and projects to the implementation of policies, plans and programs that are being assessed;

• Better context to the assessment of cumulative environmental impacts that are potentially generated by the projects under discussion.

The contribution to a sustainability processes, the generation of a decision-making context that is wider and integrated with the environmental protection and the best capacity of assessment of cumulative impacts constitute the SEA most remarkable benefits, in its potential as an environmental policy instrument. In addition, the SEA has the benefit of facilitating the process of individual assessment of the implemented projects that are a result of the plans and programs that generated it.

The Table 1, brought up from the International Study on the Effectiveness of Environmental Assessment, systematize the SEA objectives, linking them to the mentioned benefits [5, 6].

Lastly, some basic points that can guide the implementation of the SEA in Brazil are:

• The SEA is a process and not a document or a report (despite the fact that the process has to be documented, usually as a report);

• The SEA is oriented to the (strategic) decision making process and it has to influence it;

• The SEA have to discuss the strategic options while they are still in course, so that it can influence the decisions;

[Table 1]: Objectives and benefits of SEA[5, 6].

Support the process of sustainable development

promotion

Enhance and facilitate the environmental impact

assessment of projects • Decision that integrate

environmental and development aspects

• Formulation of environmentally sustainable policies and plans

• Consideration of options and environmental alternatives that are better and more practicable

• The earliest possible identification of potential impacts of governmental policies, plans and programs, and also of cumulative environmental effects of actions and projects that are necessary to its implementation

• Consideration of strategic matters related to the justification of the necessity and also to the proposals of future projects’ location

• Reduction of the necessary time and resources to the assessment of individual projects’ environmental impact

2. SEA - METHODOLOGICAL PROCEDURES

According to MMA [4] the technical procedures of the SEA involve a sequence of eight basic operational steps:

• 1° – Selection of strategic strategy proposals (Screening). This stage consists in the definition of applying to the SEA a certain PPP under analysis, this way avoiding delays in the processes of decision-making. An institutional intervention matrix and a preliminary assessment of the impacts resulting from the PPP should be defined, considering the likely direct, indirect and cumulative impacts and their synergies;

• 2° - Establishment of the timing (Timing). It is a question of verifying the PPP-type formulation schedules, in isolation and in conjunction with other stages of the SEA process, identifying cases of temporal incidence that may lead to problems and their adjustment measures;

• 3° – Definition of the content of the evaluation (Scoping). In this step, the purposes of the SEA will be established. The identification of the objectives, target audience, indicators and stakeholders. Survey of information and characterization of relevant environmental issues;

• 4° – Evaluation of strategic impacts. Prediction of environmental impacts resulting from the implementation of the APP. Identification of the changes that will possibly occur and decide if they are acceptable or not, providing subsidies for selection of the best alternative within the context of sustainability. Definition of monitoring actions of environmental quality and of the entities that are responsible for these activities and associated costs;

• 5° – Documentation and information. This step consists of presenting the results of the previous ones and of the studies and technical analyzes of the SEA, in the form of a detailed document, in order to give a support for decision makers and to give subsidy for the preparation of the final formulation and decision documents regarding PPP;

• 6ª – Review. This stage aims to control the quality of the process and the technical activities;

• 7ª – Decision making. The final decision on the implementation of PPP can be taken with security and reliability;


• 8ª – Monitoring the implementation of the strategic decision. This stage deals with the accomplishment of the actions of monitoring of the environmental quality predicted in the stage of analysis of the impacts.

According to Gonçalves [8], the SEA must to be adjusted to the different decision contexts, the different scales and evaluation objectives, and, therefore, being flexible in each case, in order to increase the chances of success in the implementation of the SEA.

3. HYDROELECTRIC GENERATION PROGRAM OF MINAS GERAIS STATE – HGPMG

The SEA, instrument of the Minas Gerais Hydroelectric Generation Program (HGPMG), held in 2007 by the Government of Minas Gerais for an energy scenario 2007 – 2027, aims to establish the conceptual and operational bases for decision making within the scope of the planning process of the Minas Gerais electric sector with respect to its purposes, strategic vision, projects and actions with the perspective of promoting the development of hydroelectric generation in an environmentally sustainable way.

The State Government, through the MGHGP, aims to generate equivalent energy to meet the state's energy demand from its own generating plant, in addition to expanding it to generate exportable surpluses. The SEA, used as a important planning tool will contribute to:• Insert the environmental variable in the process of decision

of organs and entities of the state government in which refers to investments in energy generation hydroelectric power plant;

• Evaluate the environmental and economic aspects of the of enterprises that make up the PGHMG 2007-2027, in order to aggregate a global analysis of its impacts positive and negative, as an antecedent to the process of environmental licensing of each enterprise;

• To obtain the balance of economic, social and environmental impacts of business clusters hydroelectric plants;

• Identify relevant projects that may have significant cumulative, in a given area, synergistic or even conflicting with the availability and uses of water or development.

The work was organized in 03 major phases, subdivided into 06 consecutive analysis blocks, each with a set of interdependent activities to be performed and product to be generated. In Block 01, the Initial Working Milestone is elaborated, based on the Term of Reference, with the purpose of guiding the evolution of the SEA of the MGHGP. In block 02, the characterizations and analyzes carried out had the objective of establishing the structure on which the development of the later stages, in their various themes, scopes, procedures and objectives would be carried out, guiding the directions to be followed, in order to guarantee the best results of the efforts. In this sense, all factors considered in the analyzes were characterized, in the scope of application of the SEA instrument to the MGHGP.

The Environmental Diagnosis (Block 03) comprised a critical analysis of the information identified in the socio-environmental characterization and, in this sense, is effectively a diagnosis, allowing to evolve with the dirigisme requirement. The study was based entirely on secondary data, and, therefore, results associated with the availability and spatiality of the information obtained. Throughout the Block 4 each one of the identified socio-environmental impacts were analyzed in theoretical approach, and it was also identified the degree of relative significance of each one of the impacts relative to all 380

hydroelectric uses planned by the MGHGP. In Blocks 5 and 6, the analyze and forms of presentation

of the Scenarios and the results of the EI, SEBI and EBI were consolidated. Among the eight Hydrographic Basins and respective WRPMs as presented in Table 2:

[Table 2]: Hydrographic Basins/WRPMs [8].

HYDROGRAPHIC BASINS WRPMs

São Francisco River basin

SF1 – HBC Rivers of Minas Gerais tributary to the Upper San Francisco SF2 – HBC of Pará river

SF3 – HBC of Paraopeba river

SF4 – HBC of the surroundings of the Três Marias Dam SF5 – HBC of das Velhas’ river

SF6 – HBC of Jequitaí and Pacuí rivers

SF7 – HBC of the Minas Gerais’ sub-basin of Paracatu river SF8 – HBC of Urucuia river

SF9 – HBC of Pandeiros and Calindó rivers

SF10 – HBC Minas Gerais’ tributary of the Verde Grande river

Jequitinhonha River basin

JQ1 – HBC of the Upper Jequitinhonha river Tributaries JQ2 – HBC of Araçuaí river

JQ3 – HBC of the Middle and Lower Jequitinhonha river Tributaries

Mucuri River basin MU1 – HBC of Mucuri river

Doce River basin

DO1 – HBC of Piranga river

DO2 – HBC of Piracicaba river

DO3 – HBC Santo Antônio river

DO4 – HBC of Upper Suaçuí river

DO5 – HBC of Caratinga river

DO6 – HBC Waters of Manhuaçu river

Paraíba do Sul River basin PS1 – HBC of Minas Gerais’ tributaries of Preto and Paraibuna rivers

Piracicaba/Jaguari River basin

PJ1 – HBC of Piracicaba/Jaguari rivers

Grande River basin

GD1 – HBC of High Grande river

GD3 – HBC of the surroundings of Furnas damGD4 – HBC of Verde river

GD5 – HBC of Sapucaí river CBH

GD6 – HBC of Minas Gerais’ tributaries of Mogi-Guaçu/Pardo rivers GD7 – HBC of Minas Gerais tributaries of Middle Grande river GD8 – HBC Minas Gerais tributaries of Lower Grande river

Parnaíba River basin

PN1 – HBC of Dourados river

PN3 – HBC Minas Gerais’ tributaries of Lower Paranaíba river

Source: SEA of the MGHGP, 2007.

Figure 1 shows the existing hydroelectric plants and the 380 foreseen by the Minas Gerais Hydroelectric Generation Program (HGPMG), the territorial limits of the river basins (represented by the colors) and the WRPMs, identified by the abbreviations: SF1 to SF10, JQ1 to JQ3, MU1, DO1 to DO6, PS1 and PS2, PJ, GD1 to GD8 and DO6, PS1 and PS2, PJ, GD1 to GD8 and PN1 to PN3.


[Figure 4: Hydrographic Basins, WRPMs and already existing and expected by the MGHGP [1].]

Source: SEA of the MGHGP, 2007

4. DIAGNOSTICS AND IMPACTS

Diagnosis and environmental impacts (positive and negative) were synthesized in the form of 14 thematic panels that synthesize and interrelate impact indicators with those of diagnosis, by components that are synthesis of the following topics: water resources and aquatic ecosystems, physical environment and terrestrial ecosystems and socioeconomics. Each of the thematic panels presents the justification of the

impact, methodological procedures used to read the diagnosis of hydroelectric power plant (HPP) insertion and impact, as well as the result of the impact by the HPP provided by the MGHGP and by the hydrographic basin / WRPM. Thematic panels are analyzed and presented by hydroelectric use, generating three indexes that structure this work of Strategic Environmental Assessment (SEA): Index of Environmental Impact (EI), Socioeconomic Benefits (SEBI) and of Energy Benefit (EBI). Through these indexes, each enterprise can be evaluated individually, receiving certain scores, which allow the elaboration of graphs.

For the indicators EI and SEBI, five classes or intervals of variation were established, making cuts with the purpose of maximizing the interclass standard deviation and minimizing the intraclass standard deviation, according to Tables 3 to 7:

• Very High - VH;• High - H;• Medium - M;• Low - L;• Very Low - VL or NS.

For the energy benefit or installed power, four intervals, or classes, were arbitrarily created, two of which are pertinent to the Small Hydroelectric Plants - SHPs and other two to the Hydroelectric Power Plants- HPPs.

[Table 3]: Thematic panel – Energy Generation [8].

Thematic Panel Impact Duration Indicators Observation

VH H M L VL Indicator Definition

Energy Generation

Increase in Energy Availability

Positive Permanent - 3 2 1 -Comparatives of the resultant indexes of the adverse impacts

and the socioeconomic benefits



Thematic Panel Impact Duration Indicators ObservationVH H M L VL Indicator Definition

Water Resources

Hydraulic Dynamics Alteration

Negative Permanent >6 4 to 6 2 to 4 1 to 2 <1Represents the interference related to the

hydraulic dynamics alteration

Intensification of Conflicts about

Water UsesNegative Permanent >1 0.5 to 1.0

10 to 50 days

<10 days

0Indicates the current competition scenario

for the usage of the superficial water resource

Flow regulation Positive Permanent>100 days

50 to 100 days

10 to 50 days

<10 days

0It may not represent correctly all the

approached cases and situationsAlteration of water quality and aquatic

ecosystemsNegative Permanent VH H L NS

Variables confrontation: reservoir size x WQI/ Water quality impairment degree

Depreciation of native

ichthyofaunaNegative Permanent 1≥40.7 29.3≤1<40.7 1<29.3 - -

Qualitative evaluation associated to weighted weights





Physical EnvironmentResources

Intensification of Erosive

Processes and Sedimentation

Negative Permanent VH H M L VLIndex crossing (1 to 3) in the degree of

susceptibility to erosion and sedimentation, with lithological units

Loss of Mineral Potential (Mineral

Rights)Negative Permanent VH H M L VL

Data crossing between the reservoir size and the existence of mineral rights in the reservoir

area and its surroundings



[Table 6]: Thematic panel – Terrestrial ecosystems [ 8].



Terrestrial EcosystemsResources

Interference / Pressure over the terrestrial habitats and

areas of conservationist

interests that are legally protected

Negative Permanent VH H M L VLData crossing of reservoir size with the

synthesis of the ambience reading

Erosive and sedimentation

processes intensification

Negative Permanent VH H M L VLIndex crossing (1 to 3) in the degree

of susceptibility to erosion and sedimentation, with lithological units


[Table 7]: Thematic panel – Socioeconomics [1].



Socioeconomics

Fiscal Added Value Expansion

- -2,053% - 355%

353% -

126%

124% -

30%

27% - 5%

<5%Percentage value with reference to

the fiscal added value

Municipal Collection

Increase due to the Financial Compensation

35% - 16%

15% -

10%

9% - 5%

4% - 1%

No data

Percentage Amount in Reference to the Total Revenue

Urbanized Areas Interference

Negative Permanent VH H M L VL

Data crossing of the reservoir size with the distance of the urban core with regard to the dam

(surroundings)Interference

Over the Ways of Reproduction of Traditional Populations'

Social Life and Over the Familiar

Agriculture

Negative Permanent VH H M L VL

Data crossing of the reservoir size with the highest sensibility between

reservoir counties (Interference probability over the traditional

population and familiar agriculture)

Interference over Archaeological

SitesNegative Permanent 9 to 10 7 to 8 4 to 6 1 to 3 -

Data crossing of the reservoir size and the archaeological sites potential (obtained through the crossing of the native vegetation presence index with

the potential of natural cavities)


5. RESULTS AND DISCUSSIONS

5.1 – Sc enarios comparison of MGHGP’s SEA

This study presents a set of information to be analyzed in order to construct different scenarios for each basin, considering all of the MGHGP enterprises. The acquired data indicate an expansion potential for the electrical generation in the state of Minas Gerais, through the assessment of the existing installed capacity, measured by MW for each Hydroelectric Power Station – HPS in operation, under construction or already granted. The scenarios elaborated in this study allow the assessment of the perspectives of the hydroelectric energy generation increase,

along with other possible projections of the electrical energy increasing prospects. The Expansion Scenario of the Generation Park 1 considers that all of the potential enterprises of the State will be implemented, which characterizes it as a scenario with just a few social-environmental restrictions, or a none-restriction scenario. It is also a reference to the limits of the maximum expansion of hydroelectric generation parks. This reference is important in the search for the balance between the supply and demand of electrical energy of the state, and it aims the possibility of energy exporting to other parts of the country. This scenario presents an electrical generation of around 40.4 TWh per year, as represented in Table 8.


[Table 8]: Energy Characterization in Scenario I [8]

GENERATION PARK 1 EXPANSION SCENARIO

Hydrographic Basins N° of HPPPower (MW)

Percentage in the Total Installed Power

Generated Energy

(MWh)/year

São Francisco River 101 2925 38% 15.374.010

Jequitinhonha River 16 1051 14% 5.521.954

Mucuri River 1 23 0% 118.260

*Doce River 114 2171 28% 11.410.434

Paraíba do Sul River 53 465 6% 2.445.144

Piracicaba e Jaguari Rivers

12 39 1% 202.882

Grande River 47 522 7% 2.742.392

Paranaíba River 36 496 6% 2.609.184

Total 380 7691 100% 40.424.259

* This study of SEA was performed before the environmental accident in the river Doce basin, which prevents this study, for lack of information to make a new evaluation.

Source: SEA of the MGHGP, 2007

The Expansion Scenario of the Generation Park 2 opposes the first one, since the society from Minas Gerais imposes a certain degree of restriction to the implementation of this group of projects that is part of the electricity generation potential presented in Scenario 1. This is done through the work of the agencies responsible for the implementation of environmental licensing, therefore, reducing the Scenario 1 generation expansion. The enterprises that present a “Potential Environmental Restriction” were selected, and subsequently excluded from the expansion of the generation park. This potential was represented by the selection of projects that present an extremely high significance indicator of two environmental impacts related to biodiversity conservation (ichthyofauna and terrestrial habitats) and two other impacts related to socioeconomic interference (urban areas and traditional populations/ family farming). These impacts were selected because they had less control/mitigation possibilities. This scenario presents a generation energy in the order of 20.7 TWh per year, as presented in Table 9.

[Table 9]: Energy Characterization in Scenario II

GENERAGION PARK 2 CHARACTERIZATION SCENARIO

Hydrographic BasinN° of HPP

Power (MW)

Percentage in the Total Installed Power

Generated Energy

(MWh)/year

São Francisco River 81 1.366 35% 7.180.957

Jequitinhonha River 9 331 8% 1.737.634

Mucuri River 1 23 1% 118.260

Doce River 84 1.186 30% 6.232.223

Paraíba do Sul River 50 414 11% 2.176.037

Piracicaba e Jaguari Rivers

9 33 1% 174.499

Grande River 45 449 11% 2.360.806

Paranaíba River 20 132 3% 693.897

Total 299 3.933 100% 2.0674.313


To allow the analysis of accumulation by the hydrographic basin, it was constructed variables by the sum of the individual values of Power, Generated Energy, EI, SEBI and the number of enterprises. These variables working together provide the measuring of intensity of intervention by hydrographic basin or WRPM, this way allowing the comparison on the cumulativeness of the same geographic space. The other variable are of relative character, such as, the Average Power by HPS, the Generated Energy by flooded area, the Average Power by EI and the Average Power by SEBI point. The EI, SEBI and EBI results demonstrate the performance of each enterprise related to these indexes, providing a wider and more diverse perspective of the hydroelectric potential of Minas Gerais.

In Table 10, it is represented the reductions between the Scenario 1 and 2. Worth stressing, that there is a decrease of 73% of the river Parnaiba basin potential capacity, 53% of the river São Francisco basin, 69% of the river Jequitinhonha basin and 45% of the river Doce basin. There is also an accentuated decrease on the flooded area, in the order of 91%, 80%, 60% and 53%, respectively, in other words, more proportional to the reduction of the installed power. In relation to the Environmental Impact Score (EI) and the Socioeconomic Benefits Index (SEBI), in the comparative table, the columns “Score EI” and “Score SEBI”, for these three basins (Parnaiba, São Francisco, Jequitinhonha e Doce), evidence a sharp decline relative to the negative impact (59%, 35%, 54% and 37%, respectively), as the losses of the associated benefits (64%, 49%, 55% and 45%, respectively), considering the exclusion of the HGPMG hydroelectric projects according to the most severe socio-environmental. restrictions.

[Table 10]: Comparative Reduction of Scenarios

COMPARATIVE REDUCTION

Hydrographic Basins

N° of HPP

Power (MW)

Average Power by HPP

Generated Energy

Flooded Area (ha)

Score EI

Average Power by EI point

Score SEBI point

Average Power

by SEBI point

São Francisco River

20% 53% 42% 53% 80% 35% 28% 49% 8%

Jequitinhonha River

44% 69% 44% 69% 60% 54% 32% 55% 30%

Mucuri River 0% 0% 0% 0% 0% 0% 0% 0% 0%

Doce River 26% 45% 26% 45% 53% 37% 14% 45% 0%

Paraíba do Sul River

6% 11% 6% 11% 6% 14% -4% 4% 7%

Piracicaba and Jaguari

Rivers25% 14% -15% 14% 0% 37% -36% 23% -12%

Grande River 4% 14% 10% 14% 24% 8% 6% 6% 8%

Paranaíba River

44% 73% 52% 73% 91% 59% 36% 64% 26%

Total 21% 49% 35% 49% 71% 35% 21% 42% 11%


5.2 Use of the scenarios of the Integrated Development Plan of Minas Gerais – IDPMG

The projection of the electric power demand of the State of Minas Gerais was based on the scenarios elaborated in the context of the IDPMG for the 2007-2023 period as a support for the formulation of State’s GDP hypothetical behavior, since the IDPMG also should support the strategic planning related to the implantation of electric power generating plants in the context of regional planning, considering also that the process of expansion of the generator base could be a support in the development of the State of Minas Gerais. According to the IDPMG, the increase


in electricity generation should be associated with the growth of Minas Gerais’ GPD. For this purpose, two scenarios designed by PMDI were adopted: Scenario I (Conquest of the Better Future) and Scenario III (Overcoming Adversities).

In the scenario I - Conquest of the Better Future, the state of Minas Gerais takes advantage of the main opportunities offered by the favorable external context and is part of a sustainable cycle of sustainable development, which combines high economic growth (5.0% to 5.5%), with added value and innovations in all sectors, a jump in educational levels, continuous reduction of poverty and social and regional inequalities, and recovery and conservation of environmental assets.

In Scenario III - Overcoming Adversities, the State of Minas Gerais overcomes great adversities in the external context, takes advantage of scarce opportunities and makes a leap towards the future, making the unfavorable environment a fertile ground for innovation and paradigm breakdown in various fields, With economic growth above the national average (3.5% to 4%) reinforced by the increase in exports and with increasing levels of innovation and value added in the productive sector.

The estimative, in the context of Scenario I - Conquest of the Best Future, for which the annual average GDP growth rate for the period 2003-2027 will be in the order of 5.40% per year up to 2027, and the energy consumption in 2005, which was around 41.9 TWh, assuming a GDP elasticity in relation to electricity consumption of 1.044, could reach 140.1 TWh in 2027, as shown below, that is, it will grow 5.8% a year, resulting in an increase in electricity consumption from 2005 to 2027, in the order of 98.2 TWh, as shown in Table 11.

[Table 11]: Scenario I – Conquest of the Best Future

Scenario I – Estimative of Increase in Electrical Energy Consumption – (2005 – 2027) Period

Minas Geraisincrease of

electrical energySource

Consumption 2005 (TWh) = 41.9Estimative 5000 x 8000

(365 x 24w)

Consumption 2027 (Twh) = 140.1 Estimative

Consumption increase 2005 – 2027 (TWh) =

98.2 Estimative

Rate of consumption increase in the 2005 – 2030

period = 5.80% Estimative

GDP (in billions of reais in 2005) =

174.0Minas Gerais Energy Matrix 2007 – 2030

GPD (in billions of reais in 2027) =

553.4 Estimative

GDP increase in 2005 – 2027 period (in billions of reais in

2005)379.4 Estimative

Increasing rate of PIB in the 2005 – 2027period (*) =

5.40% (*) Scenario I

GDP elasticity related to electrical energy

consumption (2005/1997)1.044

Estimative = equal to the NEP (National

Energy Plan)


Following the same procedure, the estimate of Scenario III - Overcoming Adversity - shows an increase in electricity consumption from 2005 to 2017, in the order of 61.2 TWh, as shown in Table 12.

[Table 12]: Scenario III – Overcoming of Adversities

Scenario III – Estimative of Increase in Electrical Energy Consumption – (2005 – 2027) Period

Minas Geraisincrease of electrical

energySource

Consumption 2005 (TWh) =

41.9 Estimative

Consumption 2027 (Twh) =

103.1 Estimative

Consumption increase 2005 – 2027 (TWh) =

61.2 Estimative

Rate of consumption increase in the 2005 –

2030 period = 4.18% Estimative

GDP (in billions of reais in 2005) =

174.0Minas Gerais Energy Matrix 2007 – 2030

GPD (in billions of reais in 2027) =

412.4 Estimative

GDP increase in 2005 – 2027 period (in billions

of reais in 2005)238.4 Estimative

Increasing rate of income in the 2005 –

2027period (*) = 4.00% (*) Scenario III

GDP elasticity related to electrical energy consumption

(2005/1997)

1.044Estimative = equal

to the NEP (National Energy Plan)


The Expansion Scenario of Generation Park 1, presented by the MGHGP’s SEA, evaluated the growth in the order of 40.4 TWh, then Scenario I - Conquest of the Best Future of the IDPMG, using all available potential without any restriction, economic or socio-environmental, covers about 40% of the necessary increment (98.2 TWh) to meet the demand of the State, that is, it is insufficient. For scenario III - Overcoming Adversity (61.2 TWh), the coverage of electricity consumption needs also presents a value that is far from MGHGP goal (40.4 TWh). For the Expansion Scenario of Generator Park 2, presented by the MGHGP’ SEA, growth was evaluated in the order of 20.7 TWh, that is, it is also insufficient to meet the increase in consumption of the Scenarios I and III of the IDPMG (98. 2 TWh and 61.2 TWh, respectively). These planning exercises involving quantitative scenarios carried out by the government of Minas Gerais, which are outlined in the magnitude of the elasticity of gross domestic product expansion in relation to the electric energy consumption adopted in the estimations of 1.044, deserve revision on these perspectives of consumption expansion. It is thus evidenced the need to obtain the greatest expansion of the hydroelectric plant as possible and, in a sustainable way, what implies in the solution of equations that did not exist in the past, requiring, then, the diversification of the electric matrix of mining, the use of new technologies, the improvement of energy efficiency and a holistic vision and technical capacity on the part of the entities involved.

5.3 SEA Scenario comparison with the Electrical Grid of Minas Gerais

The Electrical Grid of Minas Gerais 2007-2030, published by the State Energy Council (CONER), elucidates that the generation and transmission of electric power of the state is integrated to the National Interconnected System (SIN), and its operation is made in an integrated manner by the National


Electric System Operator (ONS), with the aim of maintaining the synergistic gains of the coordinated operation and guaranteeing the continuity, quality and cost-effectiveness of the electricity supply. In this study of the State energy matrix, the logic of the Minas Gerais insertion into the SIN was modeled in the Model for Energy Supply Strategy Alternatives and their General Environmental Impact - MESSAGE, which decides whether it is worth increasing the generation capacity or importing energy, depending on the economicity.

The MESSAGE model is used to formulate and evaluate alternative energy supply strategies for a country or region. The model finds the optimal energy supply strategy according to user-defined constraints, for example limits on new investments, market penetration rates, availability and fuel trade. In short, this model allows the formulation of energy supply alternatives, according to constraints imposed by the operating, regulatory and market conditions associated with the sources available in the energy mix of the region under analysis.

The study created two scenarios to help the State public policies: the Reference Scenario and the Alternative Scenario. The Reference Scenario elucidates that the demand for electricity in the State of Minas Gerais grows throughout the period at an average annual rate of 4.09%, and in the same period, the total generation of energy within the State grows at a lower rate of 3.30%, thus obliging the need to import the energy difference generated and consumed from the rest of the country. In the period 2025-2030, the increase in demand is almost completely met by imports, with a little increase in electricity generation within the State. According to this scenario, "Minas Gerais goes from a net exporter to a net importer of electricity at the end of the analysis period, importing about 17% of the electricity consumed", as can be seen in Table 13.

[Table 13]: Reference Scenario [9]

2005-2010

2010-2015

2015-2020

2020-2025

2025-2030

CONSUMED Average Annual

Increase

3.70% 3.80% 4.10% 4.30% 4.50%

GENERATIONAverage Annual

Increase

3.70% 3.80% 4.10% 4.30% 0.70%

DEPENDENCYNet import/

Demand0.06% 17.10%

Source: Minas Gerais Energy Matrix (2007 – 2030) The Alternative Scenario elucidates that the demand for

electricity in the State of Minas Gerais grows at an average annual rate of 3.81%, while the generation grows at a rate of 3.43%, thus showing that the state will also arrive in 2030 as a net importer of electricity, with 8.7% of its demand being met by imports (Table 14). An important factor that occurs in this scenario is the depletion of the hydroelectric potential in the State, which follows the same trend of the previous scenario with a little different characteristic of evolution.

[Table 14]: Alternative Scenario [9]

2005-2010

2010-2015

2015-2020

2020-2025

2025-2030

CONSUMED Average Annual

Increase3.40% 3.70% 3.80% 3.90% 4.20%

GENERATIONAverage Annual

Increase3.40% 3.70% 3.80% 3.90% 2.30%

DEPENDENCYNet import/

Demand8.70%

Source: Minas Gerais Energy Matrix (2007 – 2030)

Therefore, in the Reference Scenario, the estimative is 17.1%, while in the Alternative Scenario this estimative falls to the level of 8.7%. Analyzing these data obtained in the study on the demand and generation of electricity in the State of Minas Gerais between 2025 and 2030, it is noted that in both scenarios there will be a need to import energy from other states to supply domestic demand.

If we compare with the data from the SEA scenarios of the MGHGP and the IDPMG, we find that although there is a discrepancy in the order of magnitude, both studies point to a need to import energy from other states, that is, the state of Minas Gerais stops having a privileged condition as an exporter to become an importer of electricity.

6. CONCLUSION

This study presents a set of information for an analyzing exercise that considers different scenarios within each hydrographic basin, considering all MGHGP enterprises. The verified data indicates the potential of the hydroelectric generation expansion in the state of Minas Gerais, through the evaluation of the current installed capacity of each basin, measured in MW per HPS in operation, under construction and granted. The scenarios elaborated in this study allow the analyse of the prospects in increasing the generation of energy by hydroelectric plants together, with possible projections of the electric energy demand behavior.

It is represented the reductions between the Scenarios 1 and 2 of MGHGP’s SEA, where it can be seen a decrease of 73% of the Parnaiba basin potential capacity, 53% of the São Francisco basin, 69% in the Rio

Jequitinhonha basin and 45% in the Rio Doce basin. There is also an accentuated decrease on the flooded area, in the order of 91, 80, 60 and 53%, respectively, in other words, more proportional to the reduction of the installed power. The strategic environmental assessment tried to demonstrate that these rivers would be the most affected, so it suggests more support from environmental agencies in the treatment of new environmental licenses in them.

In the comparison of the scenarios of the MGHGP’s SEA with the scenarios of the Integrated Development Plan of Minas Gerais – IDPMG, it was evidenced the need to obtain the greatest possible expansion of the hydroelectric generating park


in a sustainable way, what implies in the solution of equations that did not exist in the past, requiring the diversification of the Minas Gerais electrical matrix, the use of new technologies, the improvement of energy efficiency, as well as a holistic vision and technical capacity of the entities involved.

In the comparison of the scenarios obtained from the study of MGHGP’s SEA with the scenarios of the study of the Electrical Grid of Minas Gerais 2007-2030 it is observed that in both scenarios there will be a need to import energy from other states to supply domestic demand. These scenario projections tend to widen, due to the reduction of rainfall in the state, the increasing silting of rivers, the reduction of riparian forest and springs, and the lack of energy planning to diversify the energy matrix.

7. REFERENCES

[1] Partidário, M.R.; Clark, R. “Introduction”. In: Partidário, M.R.; Clark, R. (Eds.). Perspectives on Strategic Environmental Assessment. Boca Raton: Lewis Publishers. p.3-14. 2000.

[2] Verheem, R.A.A.; Tonk, J.A.M.N. “Strategic environmental assessment: one concept, multiple forms”. Impact Assessment and Project Appraisal, v.18, n.3, p.177-182, 2000.

[3] Wood, C. “Environmental impact assessment comparative review”. London, Longman, 1995.

[4] Ministério do Meio Ambiente – MMA. Secretaria de Qualidade Ambiental nos Assentamentos Humanos – SQA. “Projeto

Instrumentos de Gestão – PROGESTÃO”. Avaliação Ambiental Estratégica. Brasília. 2002.

[5] Sadler, B. “Institutional requirements for strategic environmental assessment”. Paper presented in 2nd International Policy Forum. IAIA’98 Annual Conference. Christchurch. 1998.

[6] ______. “Environmental assessment in a changing world: evaluating practice to improve performance”. Final Report of the International Study of the Effectiveness of Environmental Assessment. CEAA-IAIA. 1996.

[7] Gonçalves, L.C. “Planejamento de Energia e Metodologia de Avaliação Ambiental estratégica – conceitos e críticas”. Curitiba. Juruá Editora. 2009.

[8] Governo do Estado de Minas Gerais. Secretaria de Estado de Desenvolvimento Econômico –SEDE. Secretaria de Estado de Meio Ambiente e Desenvolvimento Sustentável – SEMAD. “Avaliação Ambiental Estratégica – AAE, do Programa de Geração Hidrelétrica de Minas Gerais – PGHMG. 2007 – 2027”. Sumário Executivo. 2007.

[9] Minas Gerais Energy Matrix (2007 – 2030). Universidade Federal do Rio de Janeiro – UFRJ, Instituto Alberto Luiz Coimbra de Pós-graduação e Pesquisa de Engenharia – COPPE, Programa de Planejamento Energético – PPE/COPPE/UFRJ. Universidade Federal de Itajubá – FUPAI. Centro de Referência em Recursos Naturais e Energia – CERNE. Matriz Energética de Minas Gerais 2007 – 2030. Sumário Executivo. 2007.


SOFTWARE FOR GENERATING FLOW DURATION CURVES VIA REGIONALIZATION

1Cordeiro, Adria Lorena de Moraes ; 2Blanco, Claudio J. C.; 3Silva, Raimunda da Silva e; 4Pessoa, Francisco Carlos Lira

1School of Sanitary Environmental Engineering, FAESA/ITEC/UFPA. Av. Augusto Corrêa, 01 - Guamá. Zip code 66075-110. Belém - Pará – Brazil. E mail: [email protected] of Sanitary Environmental Engineering, FAESA/ITEC/UFPA. Av. Augusto Corrêa street - Guamá. Zip code 66075-110. Belém - Pará – Brazil. Phone: +55 91 3201-8858. E mail: [email protected] Engineering Master's programs PPGEC/ITEC/UFPA, Av. Augusto Corrêa, 01, Belém-PA, Brazil, 66075-110, Telephone: +55 91 3201-8858, E-mail: [email protected] of Sanitary Environmental Engineering, FAESA/ITEC/UFPA. Av. Augusto Corrêa, 01 - Guamá. Zip code 66075-110. Belém - Pará – Brazil. Phone: +55 91 3201-8858. E mail: [email protected]

ABSTRACT

Due to the lack of streamflow data in isolated regions, regionalization models have been used, including the simulation of flow duration curves. In this context, the proposed work aims to apply the software GCPV (Generator of flow duration curves) to generate duration curves. The software was developed in a graphical environment called NetBeans 8.0.2. It was performed with morphoclimatic characteristics of watersheds and regionalization models available in the literature and referring to the state of Pará. Software tests revealed its ability to simulate duration curves when compared those observed duration curves. Thus, basins lacking flow data, through the GCPV software, have an option to simulate flow duration curves for multiple water use projects, such as: hydroelectric power plants, irrigation, water supply, sanitation, water quality assessment and navigation.

KEYWORDS: NetBeans, Multiple Regression, Cubic Model, Amazon.

1. INTRODUCTION

Knowledge of flow data in a river basin is important, because it serves as a basis for planning and management of water resources. According to Gontijo Junior and Koide [1], in order for the streamflow monitoring network to be efficient, gauge stations must be installed in such a way that their density and spatial distribution in the region allow the determination of hydrological characteristics of a Region. However, Brazil has continental dimensions with a vast hydrographic network, making the densification of streamflow gauge stations to be no easy. Thus, in order to fill this gap, in relation to flow duration curves, numerous works have been produced, for example: Mendicino and Senatore [2] analyzed the performance of seven models of regionalization of flow duration curves for 19 basins in southern Italy, known as Calabria. For the definition of the regional models, they used multiple regression analysis. The statistical models showed good reliability. Yasar and Baykan [3] studied 72 streamflow gauge stations in Kansas - USA. The authors proposed a model to simulate flow duration curves, called EREFDC - Estimation of Regionalized Flow Duration Curve. The model is based on linear and nonlinear mathematical equations capable of predicting curve parameters based on variables such as: drainage area, annual mean precipitation, soil permeability, latitude and longitude. Booker and Snelder [4] constructed flow duration curves for 379 streamflow gauge stations located throughout New Zealand to investigate how parameterization and generalization methods are combined for regionalization at sites with no flow information. Multiple regression equations were applied and the regional model of generalized probability distribution of extreme values was the one that best estimated the duration curves. Costa et al. [5] performed a regionalization study of flow continuity curves for rivers in the hydrographic regions of Calha Norte and Xingu in the State of Pará. The authors tested the fit of 5 mathematical models of regression (power, exponential, logarithmic, quadratic and cubic), similar to the method of Mimikou and Kaemaki [6], and concluded that for the Northern Channel basins, the cubic model was the best fit. For the Xingu region, it was the exponential model that adjusted better.

Currently, there are several softwares for hydrological regionalization, for example, HBV hydrologic model (Seibert

and Vis [7]) was implemented in Python. This software has flexibility, computational efficiency, proven effectiveness under a wide range of climatic and physiographic conditions in the world in several previous regionalization studies. The self-written program of the model IHACRES using MS – Excel is used for the process of regionalization of flows in India (Javeed and Apoorva [8]). Saboia and Lopardo [9] presented the software "Regionaliza 2014", capable of producing some hydrological parameters for any region of the state of Paraná, Brazil. The software development was done in Python 2.7, what allows the execution of the source code in many operations systems (Windows, Linux, Mac OS, etc.) without modifications. The computational system coordinated by Euclydes [10] represented a milestone in the creation of software to carry out studies in the area of flow regionalization. The Águas de Minas Digital Atlas is a complete and up-to-date mapping of the surface water resources of the State of Minas Gerais.

Flow continuity curves are tools of great utility in the face of hydrological and environmental problems related to multiple uses of water, such as hydroelectric projects, irrigation systems and water supply; Water quality assessment, navigation systems, among others (Blanco et al. [11], Castellarin et al. [12]). With flow duration curves it is possible to determine the percentage of time at which flow is equalized or exceeded (Vogel and Fennessey [13]). Therefore, the elaboration of the GCPV software to generate flow duration curves from regionalization models to locations without data records appears as the main motivation for the work. The GCPV is registered with the INPI (National Institute of Industrial Property) under number BR512016001080-0.

2. MATERIAL AND METHODS

2.1. Data

Software input data are morphoclimatic characteristics of the watersheds. The drainage area, A (km²) and the mean annual rainfall, P (mm), were obtained through the Hydrological Information System (http://hidroweb.ana.gov.br/) of the National Water Agency (ANA); the length, L (km) and the head, H (m), which were obtained by means of GIS. These data are the



independent variables used in the cubic models of regionalization of flow continuity curves defined by Silva [14] through multiple regression, with the flows, Q% (m3/s), the daily dependent variable. These variables are represented in Figure 1. The clustering of streamflow gauge stations, the first step for the regionalization of flows, was elaborated, taking into account the dimensions of the drainage areas of the basins, originating three clusters of watersheds in the state of Pará (Figure 2).

[Figure 1: Representation of the morphoclimatic variables used by GPCV.]

[Figure 2: Spatial distribution of streamflow gauge stations of the clusters I, II and III and rainfall gauge stations.]

2.2. Regionalization and Software platform

The clusters are as follows: I with area of 465 to 15000 km², II with area of 15000 to 55000 km², and Cluster III with area of 55000 to 764000 km². These clusters are characterized by Equations 1-12 (Silva [14]), where the parameters a, b, c and d (defined for each cluster via multiple regression between Q, A, P, L and H) are positive constants.

• Cluster I

a = -24,24+0,01A+0,02P+1,6P+0,31 H (1)b = -260,1+0,02A+0,1P+4,84L+1,88H (2)c = 4,06+0,04A-0,03P+4,7L+2,79H (3)d = 214,68+0,03A-0,11P+1,25L+1,32H (4)

• Cluster II

a = 2,29.10-8.A1,68.P0,88.L0,15.H0,07 (5)b = 1,28.10-6.A1,51.P0,83.L-0,02.H0,09 (6)c = 7,68.10-5.A1,2.P0,94.L-0,24.H0,04 (7)d = 0,005.A0,79.P1,06.L-0,47.H-0,05 (8)

• Cluster III

a = 0,18.A0,83.P0,07.L0,11.H-0,04 (9)b = 0,27.A0,77.P0,25.L-0,03.H0,09 (10)c = 0,47.A0,78.P0,27.L-0,33.H0,23 (11)d = 0,31.A0,97.P0,04.L-0,85.H0,52 (12)

Thus, after selecting the cluster, A, L, H and P are required and necessary for the calculation of the flow rates and the generation of the duration curve via cubic model (Equation 13). This model was the best among those tried by Silva [14] that also tested the power, exponential, logarithmic and quadratic models. The Figure 3 summarizes the regionalization utilized in this study.

Q% = a - b. D + c. D² - d.D3 (13)

Where D is the duration in %, being divided into intervals defined by the user of the GPCV.

[Figure 3: Schema of regionalization utilized in this study.]

Where:

1. Selection of the cluster (I, II, II) according to the drainage area of the river basin without flow data;

2. Insertion of A, L, H and P of the catchment area without flow data;

3. Determination of the parameters a, b, c and d through Equations 1-12;

4. Calculation of Q% (Equation 13) in function a, b, c, d and D.5. Generation of the duration curve.

Based on Figure 3, the software was created through the graphical development environment called NetBeans 8.0.2 (Figure 4). NetBeans is a fast and easy development system for Java, mobile and Web desktop applications as well as HTML5 applications with HTML, JavaScript and CSS. NetBeans is free and open source, as well as a large community of users and developers around the world [15].

[Figure 4: NetBeans 8.0.2 initial screen in environment for Windows.]


3. 3. RESULTS AND DISCUSSION

3.1. Software presentation

In the initial screen (Figure 5), the user must inform which cluster belongs to the river basin without flow data.

[Figure 5: GCPV initial screen.]

After choosing the cluster, the software will open a window (Figure 6), in which the user enters the input data: A, L, H and P, which should be known to calculate the parameters (a, b, c and d). Then, with the calculated parameters, the user reports the durations (D) between 0% and 100%. With a click on the Graph Curve button, in the next open window (Figure 7), the flow duration curve is determined by cubic model (Equation 13).

[Figure 6: Data entry screen.]

[Figure 7: Output screen with flow duration curve plotted.]

3.2. Software test

The data of the hydrographic basin, whose flow rate is measured by Fazenda Rio Dourado Station (Code ANA 18480000), can be found in Figure 2 through its geographical coordinates, Latitude: -8: 19: 37 and Longitude: -51: 27: 37. The morphoclimatic characteristics of the basin are: A = 6860 km²; L = 241 km; H = 250 m; And P = 1827 mm (Silva [14]). Thus, the range of the drainage area to be chosen is the first (465 to 15000 km²), characterizing cluster I (Figure 8).

[Figure 8: Window for selection of the Group, to which the basin belongs as a function of the drainage area.]

After this step, the morphoclimatic characteristics of the basin are reported to the GPCV (Figure 9).

[Figure 9: Window with the morphoclimatic characteristics of the selected basin.]

With the insertion of the morphoclimatic characteristics, which are applied to Equations 1-4 of Group I, parameters a, b, c and d are calculated (Figure 10).

[Figure 10: Window for calculating parameters a, b, c and d.]

With the parameters a, b, c and d, the flows are calculated through Equation 13, inserting durations 0 to 100%, in intervals of 20% or least (Figure 11). These data are arranged in a table so that the user knows the points that are presented in the graph. Finally, just click the Graph Curve button (Figure 6) and the flow duration curve is plotted (Figure 12).


[Figure 11: Window with the presentation of the durations and calculated flows.]

[Figure 12: Simulated and observed flow duration curves of Fazenda Rio Dourado gauge station.]

Figure 12 shows the simulated and observed flow duration curves of Fazenda Rio Dourado gauge station. In this case, the observed curve was edited on the figure to demonstrate the potential of the software to simulate the observed curves.

4. CONCLUSION

Proposed software was able to simulate flow duration curves, proving to be efficient in its use for generation of these graphs. Therefore, the application of the software is important in the data simulation for regions needing hydrological information. Thus, areas without flow data have an option through GCPV to estimate flow duration curves for projects of multiple water uses, such as: hydroelectric power plants, irrigation, water supply, sanitation, water quality assessment and navigation.

5. ACKNOWLEDGMENTS

The authors wish to thank “Coordenação de Aperfeiçoamento de Pessoal de Nível Superior” (CAPES, Brazil) for a master scholarship and “Conselho Nacional de Desenvolvimento Científico e Tecnológico” (CNPq, Brazil) for an ungraduate scholarship.

6. REFERENCES

[1] GONTIJO JR. W. C.; KOIDE, S. Avaliação de Redes de Monitoramento Fluviométrico Utilizando o Conceito de Entropia. Revista Brasileira de Recursos Hídricos, v.17, n.1, p.97-109, 2012.

[2] MENDICINO, G.; SENATORE, A. Evaluation of parametric and statistical approaches the regionalization of flow duration curves in intermittent regimes. Journal of Hydrology, v.480, p.19-32, 2013.

[3] YASAR, M.; BAYKAN, N. O. Prediction of flow duration curves for ungauged basins with Quasi-Newton Method. Journal of Water Resource and Protection, v.5, p.97-110, 2013.

[4] BOOKER, D. J.; SNELDER, T. H. Comparing methods for estimating flow duration curves at ungauged sites. Journal of Hydrology, v.434-435, p.78-94, 2012.

[5] COSTA, A. S.; CARIELLO, B. L.; BLANCO, C. J. C.; PESSOA, F. C. L. Regionalização de curvas de permanência de vazão de regiões hidrográficas do Estado do Pará. Revista Brasileira de Meteorologia, v.27, p.413-422, 2012.

[6] MIMIKOU, M.; KAEMAKI, S. Regionalization of flow duration characteristics. Journal of Hydrology, v.82, p.77-91, 1985.

[7] SEIBERT, J.; VIS, M. J. P. Teaching hydrological modeling with a user-friendly catchment-runoff-model software package. Hydrology and Earth System Sciences, v.16, n.9, p.3315–3325, 2012.

[8] YUSUF, J.; APOORVA, K. V. Flow regionalization under limited data availability - application of IHACRES in the Western Ghats. Aquatic Procedia, v. 4, p.933 – 941, 2015.

[9] SABOIA, J. P. J.; LOPARDO, N. Software para cálculo de regionalização de parâmetros hidrológicos em bacias do estado do paraná. In: XXI Simpósio Brasileiro de Recursos Hídricos, 2015, Brasília. XXI Simpósio Brasileiro de Recursos Hídricos, 2015.

[10] EUCLYDES, H. P. ATLAS digital das águas de Minas; uma ferramenta para o planejamento e gestão dos recursos hídricos. 2. ed. Belo Horizonte: RURALMINAS; Viçosa, MG: UFV, 2007. 1 CD-ROM. ISBN 85-7601-082-8. Acompanha manual.

[11] BLANCO, C. J. C.; SANTOS, S. S. M.; QUINTAS, M. C.; VINAGRE, M. V. A.; MESQUITA, A. L. A. Contribution to hydrological modelling of small Amazonian catchments: application of rainfall–runoff models to simulate flow duration curves. Hydrological Sciences Journal, v.58, n.7, p.1–11, 2013.

[12] CASTELLARIN, A.; GALEATI, G.; BRANDIMARTE, L.; MONTANARI, A.; BRATH, A. Regional flow-duration curves: reliability for ungauged sites. Advances in Water Resources. v.27, p. 953-965, 2004.

[13] VOGEL, R. M.; FENNESSEY, N. M. Flow-duration curves II. A Review of Applications in Water Resources Planning. Water Resource Bulletin, v.31, n.6, p.1029-1039, 1995.

[14] SILVA, R. S. Proposta de otimização de modelo de regionalização de curvas de permanência de vazões. p. 95. Dissertação de mestrado – Instituto de tecnologia, Universidade federal do Pará, Belém, 2014.

[15] Netbeans IDE Features. NetBeans IDE – A forma mais inteligente e rápida de codificar. Disponível em: https://netbeans.org/features/index_pt_BR.html. Access May 14, 2016.

1 American Journal of Hydropower, Water and Environment Systems, july 2016

published by ACTA Editora

technical papers - latiniahr.comlatiniahr.com/docs/journal_5.pdf · american journal of hydropower,...

Documents