The State of Minas Gerais encompasses a wide variety of regions and for this reason, the diversification of energy sources in some zones of Cemig’s concession area is inevitable. Thus, the Company continually invests in research and development projects focused on developing alternative energy sources for both local generation and the rational use of energy.

The term ‘Alternative Energy Sources’ refers to the processes for energy conversion, employed as an alternative - or a complement - to the conventional generation facilities, comprised of large-sized hydroelectric and thermal plants, which burn either fossil or nuclear fuels.

However, it should be emphasized that not all development projects are totally competitive, feasible or can be assumed in a generalized form. The utilization of certain energy alternatives depends upon the association of various factors, such as availability of the resource under conditions that must be conducive to its technical utilization, in addition to the analysis of technical and environmental aspects, cost/benefit ratio and questions of strategic character, among others.

Among the various projects and studies, Biomass stands out. Recommended for the areas that do not demand a large volume of energy, it relies on technologies such as the gasification of coal, wood and biomass residues, as well as the utilization of gas in internal combustion engines. It is more viable in locations where such residues are more readily available and which face conditions restrictive to the conventional supply of power. Technologies for the gasification of wood and utilization of the gas in micro-turbines, Stirling motors and low-pressure boilers, among others, are in the process of development.

Cemig has also performed studies with the purpose of evaluating the co-generation potential of the sugar and alcohol sector. There is a significant electric energy generation potential in the rational utilization of both the sugar-cane bagasse surplus, and the waste-heat originating from sugar and alcohol production processes, depending on the investment capacity of the concerned parties.

The Company is also developing biomass related activities involving coal gasification, cooking oils, biodigestors and micro-distillers.

Coal Gasification

The purpose of this project is to power up irrigation systems and generate electricity in regions located far from the conventional electric power grid. In an experiment to test the possible applications of the energy generated by coal gasification technology coupled to internal combustion engines, those irrigation systems on the premises of the "Empresa Brasileira de Pesquisa Agropecuária" (Brazilian Enterprise for the Agriculture and Cattle Raising Research) - Embrapa, in the city of Sete Lagoas, and in the city of Itambé do Mato Dentro were found to operate satisfactorily.

The largest project for the generation of electric energy in this fashion was developed in the city of Formoso, Minas Gerais, using coal gasification to drive a diesel engine (operating on the dual system – burning 80% coal gas and 20% diesel fuel). The equipment was in operation for some five years, operating an average of 3 hours per day. It is currently deactivated.

Vegetable Oils

Cemig also carried out a few experiments involving the utilization of vegetable oils in internal combustion engines (Elsbelth and conventional diesel), to drive irrigation systems. Poison ivy, cottonseed and soybean oils were used to drive sprinkling irrigation systems in the city of Montes Claros. In the municipality of Paracatu, poison ivy oil mixed with Schur additive and alcohol were used to run a central pivot irrigation system coupled to a 250 CV pump.

Micro-distillers and Biodigesters

Cemig has already begun experimenting with the use of digesters for the production of methane gas. To this end, it has monitored and evaluated a project involving an alcohol micro-distillery developed by a cooperative in the city of Bom Despacho.

Wind Power

Aeolian energy is the source of energy that has been experiencing the fastest growth around the world, having posted an average annual expansion of 30% over the past five years. At the end of 1996, the worldwide installed capacity was approximately 6,100 MW, while in the year of 2000, the value exceeded 16,700 MW. Germany accounts for the largest part of this boom, with more than 6,000 MW, followed by the United States, Spain and Denmark, with 2,550 MW, 2,250 MW and 2,140 MW, respectively.

Wind power has been used mostly on rural properties in Brazil, for pumping water or driving small generators, on the order of hundreds of watts. The first wind-driven generator of a significant size was installed in Brazil in 1982, on Fernando de Noronha Island, to act as an oil-saving unit for a diesel powered electric generator assembly, with an output of 75 kW. On the same island, another 225 kW wind-driven generator was installed in May 2000.

In 1994, Cemig installed the Experimental Wind Power farm of Morro do Camelinho, rated at 1 MW, in the municipality of Gouvea, Minas Gerais. This was the first Brazilian wind farm to be patched into the interconnected power system.

The initial plans calling for utilization of solar and wind sources by Cemig were set out in the 60’s. In 1981, the State’s Energy Commission assigned Cemig the task of measuring the potential for solar and wind power in the State of Minas Gerais and of installing pilot systems to supply remote stations via these energy sources. Thus, with the support of Finep and Finame, two Brazilian financing agencies, the work began in 1983 and was completed in 1986. During this period, remote stations for radio-communications were installed in the cities of Pompéu (solar and wind), Morro do Camelinho (wind) and Porto Indaiá (solar), in addition to the collection and processing of data about the wind patterns from 67 anemometric stations, 58 of them owned by Cemig. Under the Energy Farm Program, a windmill was installed in the region of Uberaba, to provide power for the pumping of irrigation water.

In 1992, Cemig started studying the implementation of an experimental wind farm at Morro do Camelinho, in the Municipality of Gouveia, a project that was completed in 1994 with funds from the Eldorado Program from the German government.

After the institutional changes to the electrical sector in general, Cemig has been giving priority, in the wind power sector, to identify potential sites, in order to investigate the prospects for commercial establishment of large size wind power parks.

For this purpose, the company implemented two anemometric stations in Northern Minas Gerais in 1997, where two potentially promising sites were identified. There are plans for the installation of another wind metering station, also in the Northern section of the State of Minas Gerais, at a different location.

Cemig intends to consolidate the solarimetric data of Minas Gerais, containing all measurements gathered by its solarimetric network and those of the former INEMET (a Brazilian Research institute) and, later, to produce a Solarimetric Atlas.

Solar Energy

Solar energy already provides lighting power for some 500 homes, 150 schools and 50 community centers in rural areas of the State of Minas Gerais. The Solar Light Program, developed by Cemig, has been providing evidence of the effectiveness of photovoltaic systems as an alternative source of energy for remote areas, not served by the conventional power grid.

As implied by the name of the Project, the photovoltaic system converts sunlight into electricity, furnishing lighting and operating various devices, such as radios, TV sets dish antennas, cassette players, phones and pumps for irrigation or for the draining of potable water.

The system is composed of photovoltaic modules that, when exposed to sunrays, covert solar energy into electric energy, which is stored in batteries. At night, the energy stored in the batteries is used to power homes, schools and community center lighting and equipment.

Even on cloudy days, the rays emitted by the sun are stored by the photovoltaic systems, which were designed by Cemig so that they may operate for up to four rainy days.

This is a technology that knows no limits in practical terms. In the event that the demand for energy is high, all that is required is to increase the power of the photovoltaic generator (which may consist of one or more modules).

However, the higher the power rating, the more expensive the system gets. In order for the Solar Light Program to make economic sense for families, small rural producers and schools, Cemig has designed systems with different capacities, taking into consideration the basic requirements of each of these sectors.

Thermal Power

This initiative concerns research directed towards the utilization of solar thermal power. Such systems allow for the heating of water by tapping solar radiation. The heated water is stored in an insulated reservoir during the day and when the solar heat is not sufficient to heat the water up to the optimum temperature or in the event of excessive consumption of hot water, an auxiliary electric system is automatically activated to complement the solar heating.

A properly installed solar heating system can save up to 80% of the electricity used in baths and showers. Such a proportion, however, depends on the correct sizing of the equipment to provide the level of convenience desired by the users.

If, for example, hot water is drawn from several faucets in a home and a large volume of water is used by the showers, the equipment to be installed has to be able to accommodate the demand. Otherwise, the increased consumption shall be met by electric energy and no significant savings would be achieved.

Studies conducted by Cemig show that most of the failures of these systems are due to errors in the design of the hot water plumbing systems (56%). Inadequate architectural designs account for unsatisfactory operation of 33% of the solar heating systems that fail and errors of the system itself, such as improper installation or low-quality panels account for just 11% of the defects.

However, when the installation is properly designed, solar heating systems are very efficient. In order to avoid complications in any of the three phases of the Project, Cemig recommends that the prospective user should contact professionals – engineers and architects – who have mastered the techniques and only use panels which bring Inmetro’s (the Brazilian National Institute of Metrology) label. Cemig itself has also tested these panels.

Evidence that solar thermal energy may be the best solution for the heating of shower water in Brazil without overloading the conventional electrical system is emerging through the Solar Heating Project, which promoted the installation of six thousand square meters of panels for the implementation of solar water heating systems in residential buildings. The project was carried out in the city of Belo Horizonte, and other major cities, under the coordination of Cemig, from 1999 to 2001.

Cemig provides technical consulting regarding the design of solar heating systems and plumbing, helping consumers to save energy and reducing the load on the electrical system during the peak hours, relying on a very interesting database compiled through its studies of solar heating systems.

Other Sources of Energy

Cemig constantly strives to keep abreast of the technological evolution of other energy sources, especially renewable ones, such as to hydroelectric power and even those whose use, in the short and medium terms, has not yet been anticipated by the Company, either due to the costs involved or to their current stage of technological development. Thus, alternative energy sources such as geothermal, tidal, nuclear and others, in addition to technologies such as superconductivity and fuel cells, have been the subject of much attention. The Company also conducts research and carries out studies in the areas of small hydroelectric plants (PCH), small thermal plants (PCT), solar thermal plants and small size engine-generators sets, and other means of converting alternative energy sources.

The Luz Solar Program

In order to make the Luz Solar Program economically feasible for families, small rural producers and schools, Cemig has designed systems with different power ratings based upon the basic requirements of each of these sectors.

Homes are equipped with a system capable of providing sufficient energy for lighting and the use of either a black and white TV set or a radio for up to four hours a day. Now, schools may also feature lighting, color TVs, videocassette recorders and satellite antennas for up to four hours a day. The pumping of water from community wells, small dams and artesian wells will require an independent system, also with different configurations. The users of the photovoltaic system pay a monthly tariff for the energy used, in accordance with their ranking. In the case of homes, the rate is the same as that charged to low-income consumers by Cemig.

Under the Luz Solar (Sun Light) Program, schools and rural community centers are sponsored by the Ministry of Mines and Energy (through the PRODEEM – Program for Energy Development of States and Municipalities), the State Department of Education, the State Department of Mines and Energy of Minas Gerais, Municipal Governments and Cemig. As for the homes, the federal, state and municipal governments and Cemig are financing the investments in the systems. Anyone interested in obtaining this benefit should contact the Cemig agency in his/her town or the City Hall. Another probable "joint venture" for the establishment of the Luz Solar Program in a given area involves cooperatives. In this case, the entity would finance 36% of the system, similar to that of the city government. All primary equipment is the property of Cemig.

At this time, Cemig is installing photovoltaic power in more than 100 homes and 100 rural schools. The Company’s target is to install 6000 systems within cities of the Northern and Eastern parts of Minas Gerais by the year 2003.

Preservation through awareness

Under the Solar Light Program Cemig’s task does not end with the arrival of electricity at homes and farms. The success of the project depends on the rural communities being acquainted with their photovoltaic systems, maintaining and living with them, risk free.

It is for this purpose that training programs have been developed, through which electricians are trained in the installation and maintenance of photovoltaic systems, in addition to those trained for the commissioning and control of the systems. Such professionals attend the EFAP (Cemig’s Professional Training Center), where the Training Unit on Photovoltaic Solar Energy is located. The electricians are either employees of Cemig or of companies rendering service to Cemig. At this Training Unit, the students see models of the system applied to various situations (homes, water pumping, schools, public lighting) in classrooms that are especially equipped for technical training.

Users of photovoltaic energy also participate in seminars on the technology and learn how to take the necessary precautions that assure the proper operation of the system. Children attending schools supplied with electricity from solar sources also receive guidance from trained personnel, complemented by an entertaining booklet (a comic book type publication), showing them how they can help to protect the technology that is so beneficial to them.