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Immediate and future solutions for the generation of electricity

Various research projects financed by FAPESP bring new perspectives to traditional methods and production alternatives for electrical energy

In the midst of the Brazilian energy crisis, the search for quick solutions that will fortify the present methods of electricity generation and consequently eliminate the possibility of blackouts is growing. However, rapid and magic solutions do not exist. There do exist solutions worked out after years of study, such as the work of professor Secundino Soares Filho, of the State University of Campinas (Unicamp). Together with his team, he has developed two software programs that can improve by 5% the energetic performance of hydroelectric power stations, the source of 92% of the electricity of the country.

Another possibility for an increase in the so necessary number of megawatts is in getting better use from the extraction of electrical energy via the extract and stock of the sugar cane bagasse. Also, besides the traditional systems of electrical energy generation, a new technology will, within the next few years, find space in homes, hospitals and small industries. The technology is fuel cells, equipment that works with pure hydrogen or hydrogen extracted from natural gas. Other good news comes from two new products developed at Unicamp and at the University of São Paulo (USP) that should lower the cost for the production of the equipment of solar energy systems.The solutions have as their base a strategic outlook, even though some might be used in a short period of time. They involve researchers from research institutions and from companies, lots of studies, planning and innovative solutions.

An increase now
For more than ten years, the improvement of the hydroelectric power stations has been a theme of study at the Laboratory of Hydrothermal Power Systems of the Electrical Engineering School and of Computing. There professor Secundino Soares Filho has already generated two computer software programs capable of producing, without new engineering works or large investments, an increase of 5% in national production of electrical energy that corresponds to 2,250 megawatts (MW) of power. This number is equivalent to the average production of the eight hydroelectric power stations installed on the Paranapanema River, at the border of the states of São Paulo and Paraná, and corresponds to the quantity of energy that the rationing plan is longing to save through home consumption.

“If these new technologies, that would improve the performance of the turbines of the power stations and would optimize the administration of the water stocked in the reservoirs, were implanted throughout the whole of the Brazilian hydroelectric dams, then rationing would be a lot less severe”, states the professor from Unicamp. He verified that there had been insufficient investment in the generation of the system over the last few years. So much so that, while the demand for energy within the country rose by 5,000 megawatts per year, the supply of generation grew only by 3,000 megawatts.

Careful management
For some time now professor Soares Filho has been calling people’s attention to the risk of rationing. In an article published in issue 41 of Notícias Fapesp, of April 1999, he was categorical in his remarks: “A more careful management of the reservoirs would contribute towards a reduction in the risk of energy rationing, forecast for the next few years if the investments in the sector continue to be postponed.” Two years after his warning, Brazil is confronting blackouts.

To help to revert this situation, software developed by the specialists from Unicamp represents an important role in increasing the production of energy within the country. They were developed in the context of the thematic project Planning and Programming of the Systems Operation of Electrical Energy. The first of the software programs deals with the control of the turbine machinery. With this program it is possible to increase productivity by 3% in the hydroelectric power stations.

To understand this benefit it is necessary to know that every turbine has a performance curve called the “Hill curve”. It depends on two parameters, rate of flow and fall of water. The greater the fall of water, the greater the power. The mathematical model formulated by the Unicamp team evaluates the performance of each turbine as a function of the available rate of flow and of the height of the fall of water and determines the overall performance of the assemblage.Errors in this complicated equation represent a loss of precious megawatts. “We have already proven the efficiency of our model in the power stations on the Paranapanema river and we have simulated a test at the Itaipu power station. In both cases, the saving was of 3%”, says the researcher. The results in Paranapanema were so impressive that the generating company, Duke Energy, signed a contract with Unicamp to the value of R$ 345,000.00 for the application of the model in their eight hydroelectric dams: Jurumirim, Rosana, Chavantes, Capivara, Canoas I and II, Salto Grande and Taquaruçu.

Downstream
The other application developed by the Unicamp team coordinates the volume of water of the reservoirs. The essence of this model is the transference of the volume of water upstream, close to the springs of the rivers, to the downstream hydroelectric dam closer to the mouth of the river. This swap will increase 4% the generation of the power stations that operate with a reservoir. These hydroelectric power stations correspond to 45% of the energy capacity installed in the country; the other 55% are of stations working off water streams whose reservoirs cannot be controlled. If this control system proposed by professor Soares were implemented by the National Operator of Electrical Systems (ONS), the saving would be some 2% more in the energy performance of hydroelectric power stations with reservoirs.

Water in the wrong place
In order to prove that the model works, the Unicamp researcher carried out a simulation, taking as his base the situation of three power stations of the Southeast system, on the 15th of February of this year: Emborcacão on the Paranaíba river, Furnas on the Grande river, and Ilha Solteira on the Paraná river. On that day the three power stations were operating, on average, with 27% of total water capacity and were generating 2,667 MW. “If the ONS had maintained the same rate of flow at the three units, but had concentrated the volume of water at the last power station of the waterfall, in this case Ilha Solteira, the energy generation would have increased to 2,778 MW, an increase of 4.13%. This demonstrates that the water is stocked in the wrong place.

They are stocked at the headwater when they should be stocked in the downstream reservoirs.”Soares Filho understands that the application of the model of the control of the turbine machinery is much more practicable than that of the management of stocks, because this latter method has a complication. For the system to work better, the station at the headwater would have to give up generating electricity in favor of the downstream station. “The way things are today, everybody is losing.” underlines the researcher.Both the model for the control of turbine machinery and the administration of the reservoirs are part of a more complex software baptized as HydroLab, which, in practice, is a sophisticated laboratory for the analysis of the Brazilian hydroelectric system.

The HydroLab also includes an extensive data bank and a forecaster of rate of flow that attempts to “guess” when it is going to rain during the period of a year within the basins of the stations. This data is fundamental for an improved administration of the hydroelectric power stations and could avoid situations such as we are living today. “Our software makes forecasts that are much more exact and has an error rate equivalent to half of that applicable by Eletrobrás that uses a model from the 80’s.” explains the researcher.

Reduced return
Through the HydroLab program, it is already possible to know that, with a full reservoir the Furnas power station has the potential to generate 405 MW, but at 20% of its capacity, which corresponds to the situation at the end of May, the potential to generate electricity falls to 345 MW. This demonstrates that the fall in the volume of water in the reservoirs implies a reduction in the productivity of the power station because its potential is proportional to the product of the rate of fall with the fall of water. “We are spending more water for the generation of the same amount of electricity”, explains the researcher.

Professor Soares Filho is on his third consecutive thematic project, all with the same objective: to maximize the national production of electrical energy. In order to develop this aim, as well as the Unicamp team, there is collaboration from researchers in engineering, mathematics and computing at the São Paulo University (USP) in San Carlos, and of engineers at the São Paulo State University (Unesp) in Bauru.

Biomass of the sugar cane bagasse
Besides improving the performance of the hydroelectric power stations, Brazil has the potential to generate a further 2,500 MW of electrical energy from the biomass of the sugar cane. This value represents close to 20% of the capacity of the Itaipu hydroelectric power station, the largest in the country. “The bagasse and the sugar cane straw could, within a short space of time, become important components in the energy matrix of Brazil”, believes professor Isaías Carvalho Macedo, an assessor in the area of energy of the Unicamp Rectory and who, for seven years, was the technology manager of the Cooperative of the SugarCane, Sugar and Alcohol Producers of the State of São Paulo (Copersucar).

“However, for this scenario to become a reality, it will be necessary to make investments and to have an energy policy that allows the sector to develop its potential.” Today, almost all of the electrical energy production of the sugar cane alcohol distilleries corresponds to close to 1,100 MW and is destined towards internal consumption. Less than 100 MW are sold to the national grid. The reason is simple; the price paid by the distributors to the distilleries is still very low and doesn’t cover the cost of generation.The mastery of energy production technology through biomass of the sugar cane has been in existence for more than 20 years in Brazil. In 1980, the mills produced 60% of the electricity that they consumed with the burning of the sugar cane straw. Now they are self- sustaining and generate 100% of the energy that they need.

A simple process
The system for the generation of energy from sugar cane straw is relatively simple. At the start of the process, it is burned in a conventional furnace. On leaving the furnace on average at 20-atmosphere pressure, the steam drives a turbine which for its part activates an electrical generator. The steam leaves the turbine and its thermal energy is used for various processes such as the heating and the evaporation of the sugar cane syrup used to produce sugar, as well as the concentration used to produce alcohol. This complete process is named co-generation, as it results in the production of electrical and thermal energy at the same time.

According to Macedo, the energy productivity of the biomass runs to about 20% with the current technology. However, a new process that is being developed will be capable of doubling this productivity. This is the Biomass Integrated Gasification/Gas Turbine (BIG/GT). It is being developed for the sugar cane industry by Copersucar in conjunction with the Swedish company TPS (Termiska Processor Sweden). The production flow of this process is different. The bagasse is heated in a closed system without air, thus generating a mixture of gases. These gases are treated and run a special gas turbine producing electrical energy. “Well adjusted, this system can transform 40% of the possible energy of the biomass into electricity”, says Macedo.

Presently, sugar cane production in Brazil is close to 300 million tones per year and approximately 70% of this volume, 200 million tones, is processed in 130 mills in the State of São Paulo. For this sector to provide 2,500 MW of energy, it will be necessary to modernize the mills, which would have to be equipped with new generating systems. With some other alterations in the productivity cycle, the mills could get to a surplus of 3,000 MW of energy. This value corresponds to the energy generated during six months, since the mills only work from May until September. In this case the effective annual potential would be of 1,500 MW and the remaining 1,000 MW needed to reach the target of 2,500 MW could come from the burning of the sugar cane straw which today is not integrated into the process.

A straw collection
It is at this point that the research of professor Oscar Antônio Braunbeck, coordinator of the Laboratory of Projects and of Agricultural Machinery of the Agricultural Engineering School of Unicamp, comes into operation. Through an research assistance project financed by FAPESP, he has developed technology to mechanize the collection of the sugar cane straw which historically has been manual.” The sugar cane sector demands the annual removal of 80 tons of sugar cane per hectare, 20 times more than any other agricultural product.”

The mechanization of the process is the only alternative for the utilization of the straw, as it would avoid the burning of the sugar cane fields, a practice that is done on 80% of the plantations. “Mechanized harvesting doesn’t exist because the available technology, of Australian origin, is inefficient”, he says. “These machines have a series of limitations which end up making them unfeasible on the plantations.” Professor Braunbeck’s research aims to build a new machine which improves on four basic functions: the cutting of the points, the cutting of the base, chopping and aeration. “We already have a pilot unit that does the base cutting and the removal of the chaff. The technology that we are creating will stimulate a smaller loss of raw material and, at the same time, will collect less earth”, explains the researcher. With the technology available today, the losses in mechanized harvesting run to 10%.

According to estimates done by technicians within the sector, half of the sugar cane plantations of the country, those with up to 12% of ground slope, could be mechanized. Of these plantations, it is believed that it would be possible to recover 50% of the straw without causing any harm to the environment. The agronomists defend the idea that it is beneficial to leave a little of the straw on the plantation since it would act like a herbicide and conserve the humidity of the soil. Using a general calculation, 25% of the straw, close to 12 million tones, would be recoverable and could be used as biomass for the generation of energy, with an extra potential of 1,000 MW.

The expectation of professor Braunbeck is that the tests with the first prototype start up at the end of the 2003 harvest. “We hope to turn over the project to an industrial company (not chosen yet) in 2005, and I believe that in 2006 we shall have the first commercial units available for sale.”

Advances in solar panels
New savings in electrical energy could also be obtained through improvements in the systems for the use of solar energy. Though still an expensive way of generating electricity, the development of new technologies indicates that, within a short period of time, solar energy could have its use amplified through the employment of photovoltaic cells made from cheaper materials.

In the Laboratory of Inorganic Photochemistry and Energy Conversion of the Chemistry Institute (IQ) of USP, professor Neyde Yukie Murakami Iha is coordinating a team that is developing a photo electrical chemical solar cell that could cost 50% less than the cells that presently exist on the market. The IQ-USP has developed all of the processes involved in the making of a new cell also called a solar cell sensitive to colors or the so called dye-cell. This is an alternative that has been studied in various countries, though it is still not on the market. One of the attractive characteristics of this cell is its transparency which allows its installation in the place of windows. In this way, large surfaces with dye-cells can capture solar rays and transform them into electrical energy for use in the building where they are installed.

An energy sandwich
The research coordinated by professor Neyde is developing specific colors and solar cells that make use of cheap semi-conducting material and which areeasy to process, such as titanium dioxide (TiO2). This material is largely used by various sectors of the white paints, toothpaste and cosmetics industries. “We developed a film of titanium dioxide that can receive color extracts of diverse colors, in accordance with the application”, explains Neyde. “These components are set in layers forming a type of sandwich with the mediator (or electrolyte), that closes the circuit and results in a regenerative solar cell that can generate energy for many years”, explains the chemist Christian Graziani Garcia, a doctorate student and one of the participants in the research.

The dye-cells could get to a rate f 11% efficiency in the conversion of solar energy into electrical energy using liquid electrolytes. The traditional photocells using high purity silica yield between 14% and 16%, a difference that should decrease with the development of research during the next few years. “The silica cells have been in existence since the 50’s and the data from scientific literature indicate that they have reached their maximum level while the new cells have a large potential to increase their efficiency”, states Neyde. According to her, there are studies that indicate the maximum theoretical efficiency for the dye-cells to be 27%.

With its existing potential and the fact that the research covers all of the steps involved in its manufacture, the cell developed at the IQ-USP has already received inquires of business interested in commercially producing it. “There have been scores of consultations and some formal proposals (companies and venture capital funds)”, related the researcher. Because of this, the group already owns a patent through the National Institute of Intellectual Ownership (INPI) and another is in final process.

Another solar cell with characteristics similar to professor Neyde’s, is under development at the Laboratory of Conducting Polymers and Recycling of the Chemistry Institute of Unicamp. A study, going on since 1996 and coordinated by professor Marco Aurélio De Paoli, has resulted in an electrochemical cell with a solid and dry electrolyte. “We are using a polymer ceded to us by the Japanese company Daiso that produces this type of product for the automobile industry”, relates professor De Paoli. “We have managed an energy efficiency of 6%, the highest among the prototypes of chemical photoelectric cells with solid electrolytes and a glass substrate.

“According to professor De Paoli, the advantage of the dry electrolyte is the better energy stability and the elimination of possible leaks. He has registered this cell with the INPI and is preparing a cell using a substrate of flexible plastic that presents a productivity of 2% efficiency and very low costs when compared with the cells currently on the market. The studies of the researchers at USP and at Unicamp are important technological advances and unprecedented that give credentials to the new cells and takes up a place of distinction in the sector of solar energy.

Curiosity: the fuel cell
The traditional forms of generating electrical energy are going to get a strong and secure companion. The energy outlook for the 21st century points to hydrogen as the most promising fuel for use in vehicles or in station for the generation of energy. An element present in the compound of water and in almost all organic compounds, hydrogen powers the fuel cell, a silent piece of equipment that transforms chemical energy into electrical energy, work. The cell can be explained as a sandwich of electrodes, catalysts and an electrolyte.

It can receive pure hydrogen or that obtained from natural gas, from gasoline, from methanol (wood or cereal alcohol) or from ethanol (the alcohol used in Brazilian cars). For now, to remove hydrogen from water is still a very expensive option because the process of electrolysis that separates the atoms of hydrogen and oxygen requires considerable electrical energy.

Cheaper and more efficient
The fuel cell is a piece of equipment that doesn’t cause damage to the environment. It generates as residues, only water or steam, when using pure hydrogen, or very low emissions of pollutant gases through other fuels. With all of these characteristics, it is not surprising that all over the world there is a technological race for the perfection of this electrical generator.

The research centers of academic institutions and of companies are making advances in the development of materials and processes that will make the process cheaper and more efficient. For at least three years, in the United States, Canada, Germany and Japan the first cells have been sold, still with a restricted production and under order. There are today various prototypes with the capacity of providing electricity of between 10 watts (W) and 11 megawatts (MW), that might serve as much as for portable equipment as to the generation of energy for small towns.

Brazil, happily, has not remained out of this innovation. Next year the company UniTech should be putting on the market the first units of fuel cells capable of generating electricity for residences and small industries. The fuel will be natural gas. “With adaptations we can also use ethanol”, states the 44 year-old chemist Antonio César Ferreira, the coordinator of the company’s projects. The UniTech cell will work as if it were an oven that makes use of street gas or bottled gas. “All the equipment is the size of a small refrigerator. With it, it will be possible, for example, to generate electricity within one’s home and to sell the excess to your neighbor.”

Dr. Ferreira brought to Brazil his experience of nine years working in the United States. Firstly at the Texas University in the Department of Agriculture and Mechanics (AeM) and afterwards at the company MER in Arizona, where he coordinated projects for government organs as Nasa, the North American Space Agency, the Army and the Department of Energy, as well as companies such as Asahi and Mazda, always with the theme being fuel cells.

“I came back because I obtained financing from FAPESP”, relates Ferreira, who had a project approved within the Small Business Innovation Research (PIPE). “I sent my project proposal in 1997 while I was still in the States.” he recalls. In the following year he set up his company in his home town of Cajobi, close to São José do Rio Preto, in a family building.

In order to assemble the first fuel cell prototypes Dr. Ferreira needed to develop the bipolar separator plates (catalysts), essential pieces for the assembling of combustion cell prototypes. It is on the catalysts that the breakdown of the hydrogen molecule (H2) takes place. The protons (H+) originating from this reaction reach, by way of a membrane, the anode side (negative) of the cell to form water. Meanwhile, the electrons originating from the reaction of the breakdown of hydrogen (H2) circulate through the separator plate, generating electricity.

Since the 80’s
In Brazil, one of the first study groups on fuel cells began at the Chemical Institute of São Carlos (IQSC) of the University of São Paulo (USP). During the decade of the 80’s, under the coordination of professor Ernesto Rafael Gonzalez, the first laboratory prototype of this type of equipment was constructed in the country. “Between 1981 and 1982, I spent two years at the National Laboratory of Los Alamos, in the United States, studying fuel cells and other applications for hydrogen”, recalls professor Gonzalez.

Over the years, he has points out to various pieces of work in the perfecting of materials and processes linked to the technology of fuel cells and batteries, including a patent on a method of manufacturing catalysts for cells, not yet used commercially. Another noteworthy piece of work is really a curiosity and at the same time demonstrates the degree of development of the USP team. “The electrodes used in the first fuel cell in South Korea ten years ago, were developed in São Carlos”, reveals Gonzalez, who today is coordinating a thematic project linked to electrocatalysis and fuel cells. During the 80’s, he also orientated the masters and doctorate theses of Dr. Ferreira, of UniTech.

Another Brazilian research group involved with fuel cells is at the Institute of Nuclear and Energy Research (Ipen). Their studies began in 1997 and concentrated themselves in the production of materials that make up the electrodes and catalysts. The group got going with the arrival in 1998 of professor Hartmut Wendt, of the University of Darmstadt in Germany. Dr. Wendt came to Brazil at the invitation of professor Marcelo Linardi, who makes up part of this group, and through the financial assistance to visitors conceded by FAPESP.

Currently, Linardi is finishing a project financed by the Foundation on the development of electrodes and other processes linked to cells. On the agenda of Ipen are two types of cells that also could be used in cars. They are the PEMFC cells, e Proton Exchange Membrane Fuel Cell, a type of technology also developed by Dr. Ferreira, of UniTech, and the SOFC cell, Solid Oxide Electrolyte Fuel Cell. “Our idea is to develop a line of research that leads to the construction of a prototype of a few kilowatts”, explains Dr. Linardi.

The transference of the technology of fuel cells could become reality through a possible deal between the institution and the company Electrocell, incubated through the program of the Incubation Center for Technological Companies (Cietec), located in the Ipen building at the University City in São Paulo. At the moment, the company Electrocell, as well as developing cell technology, is looking for venture capital investors in order to implant a production line. It has, among its four partners, two owners of companies also incubated through Cietec who have funding through the PIPE program. Gilberto Janólio, with the company DCSystem, is developing special lithium and titanium batteries to supply telecommunication equipment, and the also engineer Gerhard Ett, of Anod-Arc, who is working on a technique for the treatment of the surface of aluminum that is superior to the conventional process.

A world theme
“Today there is an international movement in favor of efficient and clean energy such as fuel cells, and Brazil has a great opportunity to be one of the leaders among the Iberian-American countries”, says Gonzalez. He is USP’s representative on the recently created National Reference Center of Energy from Hydrogen (Ceneh), installed at Unicamp and composed of various entities and coordinated by professor Ennio Peres da Silva.

“Our intention is to begin with the integration of various groups that are carrying out research into hydrogen and to establish an ample data bank of information” ,explains Gonzalez. A study that it is hoped to bring good news to the field of Brazilian energy research, just like the software of professor Secundino, the increase in megawatts with the maximizing of the use of the biomass of the sugar cane, as well as the development of fuel cells and new solar panels. News that not only are welcome, but of top priority.

The projects
1. Planning and Programming of the Operation Systems of Electrical Energy (99/12737-9); Modality: Thematic project; Coordinator: Professor Secundino Soares Filho – Unicamp; Investments: R$ 80,300.00 and US$ 84,848.56.
2. Modeling, Simulation, Maximizing and Construction of a Basic Surface Outline Cutter for Gramineous Harvesting Process (99/04745-1); Modality: Regular line of research assistance; Coordinator: Dr. Oscar Antônio Braunbeck – USP; Investment: R$ 8,483.75.
3. Conductor and Recycling Polymers (96/09983-0); Modality: Regular line of research assistance; Coordinator: Dr. Marco Aurélio De Paoli – Unicamp; Investments: R$ 99,226. 48 and US$ 136,948.02.
4. Photo Reactivity of Compounds of the Coordination and Conversion of Energy (13/25173-5); Modality: Regular line of research assistance; Coordinator: Professor Neyde Yukie Murakami Iha – USP; Investments: R$ 97,837.56 and US$ 106,610.71.
5. Electro Catalysis Part III. Kinetics and Mechanism of the Electrochemical Processes in the Conversion and Storing of Energy (99/06430-8); Modality: Thematic project; Coordinator Professor Ernesto Rafael Gonzalez – USP; Investments: R$ 310,340.00 and US$ 365,314.00.
6. Advanced Materials for the Manufacture of Bipolar Separators for Fuel Cells of Ionic Polymer Conductors (97/13109-6); Modality: Small Business Innovation Research (PIPE); Coordinator: Dr. Antônio César Ferreira – UniTech; Investment: R$ 192,024.00.
7. Development of Electrodes and the Process of the Doping of the Electrodes of the Proton Exchange Polymer Membrane Fuel Cell (99/03257-3); Modality: Regular line of research assistance; Coordinator: Dr. Marcelo Linardi – Ipen; Investments: R$ 53,291.55 and US$ 29,684.63

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