Hydropower has been the leading Brazialian energy source for electricity generation for several decades. This is due to its economic competitiveness and its potencial at national level. Brazil has a generating system with installed capacity of more than 150 GW, with hydroelectric predominance. This predominance derives from the extensive territorial area of the country, with many plateaus and mighty rivers. The Brazilian hydroelectric potential is estimated at 172 GW, of which more than 60% have already been used. Approximately 70% of the untapped potential is located at the Amazon and Tocantins - Araguaia basins. Hydropower is a mature and reliable technology that, in the context of increased concerns about GHG emissions, has the additional advantage of being a renewable source of generation.
From the system operation point of view, hydroelectric power plants are flexible resources that provide a series of ancillary services, such as automatic generation control and voltage and frequency control. Many hydroelectric power plants in Brazil have reservoirs, which allow them to regulate the river flows, transferring water from wet periods to dry ones and, in some cases, from wet years to dry years. In addition, their reservoirs can provide several water uses, such as: flood control, irrigation, industrial processing, water supply for human consumption, recreation and navigation services. The reservoirs regularization capacity (storage capacity) in terms of total electricity consumption has been decreasing in recent years, due to the notorious difficulties to build new hydroelectric power plants and, in special, large reservoirs.
EPE develops Hydrographic Basin Inventory Studies; Integrated Environmental Assessments (AAI), Hydraulic Basin Potential Inventory Studies, Technical and Economic Feasibility Studies (EVTE) and Environmental Impact Studies (EIA) of hydropower projects. All studies consider economic, environmental and social factors, requiring constant interaction with communities, regulators, private companies, civil entities and environmental agencies.
EPE carries out the technical and economic evaluation of the uprating of hydroelectric power plants whose concessions have been extended, including the total investment and the estimation of the new firm energy (garantia física) certificate. Our assessments are the basis for ANEEL's tariff setting.
Moreover, EPE is responsible for calculating the value of investments linked to reversible assets (VNR in Portuguese acronym), for purposes of indemnification related to the undepreciated portions of hydroelectric power plants whose concession contracts are about to expire.
In the case of pumped storage, EPE is developing a methodology for its sizing and conducts studies to identify potential sites for project implementation.
EPE also provides a system (called SISORH) for the budgeting of civil works for hydropower projects with corresponding databases of references of price for equipment, materials and labor costs.
The thermoelectric power generation can use different fuels: natural gas, biomass, coal, nuclear, fuel oil and others. The definition of fuel for generation, especially for large-scale power plants, is related to meeting technical, economical, logistical, environmental and, in some cases, energy policy criteria.
Depending on the type of fuel and the generation technology, they can fulfill different roles, from base-load genereation to back-up generation for renewables or serving peak demand.
Having thermal power plants in the system generation portfolio is strategic for the Brazilian power sector. Taking into account the relevance of hydropower in Brazil, thermal power plants have been operating significantly during periods of critical hydrological conditions. Besides that, with the increasing importance of wind and solar power plants in the power system, it is more likely that thermal power plants act to compensate the generation variability of these sources in the short-term.
In the case of bioelectricity, there are also advantages from the socio-environmental point of view: like any combustion process, the burning of biomass generates CO2 emissions. Nonetheless, it is considered that emitted carbon is the same as that absorbed by the plant during the photosynthesis and, therefore, the CO2 emission balance is zero. Another advantage is that most of the fuels are by-products (waste), such as sugarcane bagasse, cellulose and paper industrial residues, wood residues, agricultural residues such as rice hulls, among others. Thus, at the same time that the greater use of the available resources is guaranteed, the inadequate disposal of such materials is avoided.
Finally, EPE carries out planning studies on various subjects related to thermoelectric power generation, such as fossil fuel future prices forecasts, including fuel oil and natural gas; the analysis of potential participation of different types of power plants in the electric power sector, for example, cogeneration plants from the sugar and alcohol sector; and studies with the perspectives of participation of various power plants, considering different technologies and fuels.
The use of wind for electricity generation became relevant worldwide from the 1990s through significant technological advances, great incentive coming from environmental concerns, with a focus on greenhouse gas emissions, and the energy independence of non-producing countries of coal, oil and gas.
Given the great potential of the Brazilian wind resource and the challenges inherent to the insertion of the source in the SIN, EPE works to ensure that wind energy is safe and economically included. Therefore, studies are carried out on the effect of wind power in the planning of the expansion of the SIN. These studies are based, among other data, on the accounting of the energy generated by the parks already in operation and the wind measurement at all the winning parks of the energy auctions.
The environmental effects of the installation of wind farms are also considered. In this sense, although the negative impacts associated with wind generation can be classified as low, they should not be neglected.
Besides planning the expansion and the maintenance of the wind resource database, EPE is responsible for the technical qualification of wind power projects that are willing to participate in pówer auctions, analysis of changes in technical characteristics and the revision of firm energy (garantia física) certificates.
Solar Photovoltaic (PV) energy is obtained through the direct conversion of light into electricity and is based on the photovoltaic effect, which is the appearance of an electric potential difference at the end of a semiconductor material structure, produced by the absorption of light.
PV power generation has great locational flexibility, especially in the case of distributed generation, and its installation is rapid given the short time required to execute the projects.
Among the main benefits of the use of solar energy, it is observed that during its conversion to eletricity there is no emission of pollutants, such as particulate materials, NOx, SO2, CO and nor GHG, which is extremely positive for the environment on a local and global scale.
Brazil is a country of great potential for the large-scale use of the solar energy source for power generation. It occurs due to several favorable natural characteristics, such as high levels of insolation throughtout the country. These factors potentiate the attraction of investors and the development of the energy source, allowing us to glimpse an important role for this source in the electricity matrix.
EPE has carried out studies on solar PV with the objective of supporting MME strategy of increasing solar energy share in the Brazilian power generation matrix, and also to identify its potential of electricity generation.
It is important to highlight that since the first energy auction in which solar energy source appeared (2013), the number of solar PV developments registered in power auctions has increased considerably.
In addition to the "traditional" generation sources, EPE has carried out studies to consider other generation sources in the system, both in terms of technological innovations in existing source, new technologies and in the combination of existing sources, such as:
Hybrid plants: It is the case when two or more energy sources present complementarity in their energy production over time. The "perfect" complementarity between two sources occurs when the little or no-availability of one the sources is compensated for the maximum availability from the other(s) source(s). EPE carries out studies aiming at encouraging further discussion on this topic and to propose a consistent methodology to assess the complementarity between the sources, especially for studies of the transmission system.
Batteries: Energy storage devices can be useful for balancing production fluctuations of intermittent renewable sources. The concept is to store energy in periods of abundant generation for later use, such as at peak periods or at low power generation intervals. The batteries, boosted by the development of the electric vehicle, have made great technological advances in recent years and still have the potential to reduce costs. Depending on this reduction and with the advantage of multi-scale deployment, batteries can be used as a source of storage for the electric power system both at the supply side and also as a demand response tool. EPE is studing various storage technologies and their possibilities for the SIN and off-grid systems as well as their related environmental issues.
Besides, EPE is developing an economic-financial model and is studying the enviromental aspects to better evaluate the potential of such resources.