Connection of Wind Power Plants at Brazilian Integrated Power Grid.

Since the late 90s, with the unbundling of the Brazilian electricity sector, generation, transmission, distribution and trading of power were separated into distinct segments, with centralized planning being carried out by the Energy Research Company (EPE, Empresa de Pesquisa Energética in Portuguese). Despite the fact that EPE is a single company, generation and transmission planning are two different tasks, fulfilled by different teams, leading to global solutions which may not be optimized. Given the large geographical area of Brazil, power plants are often allocated far away from load centers, what leads to high costs for the expansion of the transmission system due to constant increasing distances. Due to the characteristics of wind generators of being random and unstable over time, the electric system needs the maintenance of hydraulic and thermal plants operating in the base, as well as heavy investments in voltage and frequency control equipments. As the granting of the generation and the transmission system are different processes, it is possible to start operating in different dates, what leads to generation without transmission sometimes or transmission without proper use. Wind power generation has had a strong growth over the past decade due, in part, to tax incentives and other subsidies from national, regional and municipal governments. In 2015 Brazil had around 350 wind power plants totaling 8,7 GW of installed capacity [1]. Besides those, there were others 400 granted projects to add more 9,8 GW to the National Interconnected Grid (SIN, Sistema Interligado Nacional in Portuguese). The transmission system is not intended only to the dispatch of those plants. Indeed, Brazil has auctioned around 10,000 km of transmission lines and 50 new substations, associated directly or indirectly to connect wind power plants. In this paper, a comprehensive analysis is carried out, regarding wind generation plants already granted and in the final planning stage, as well as the necessary transmission facilities for the power flow of this potential. The greatest potential for wind generation are in the Northeast and Southern regions, while the higher load concentration is in the Southeast, where São Paulo and Rio de Janeiro are located. The real price of energy is compared with others alternative energy sources, such as hydraulic and thermal power generation with less transmission lines associated. Moreover, the effects on the SIN and the overcost to the consumer due to the mismatching of transmission and generation are analyzed. There are concession contracts in which the generator has been guaranteed payment for energy, whether the necessary transmission system for their dispatch starts operating on the contracted date or not. This situation has been commonly due to environmental and real estate acquisition difficulties for the construction of transmission lines. The conclusion is that an integrated energy planning is needed, as well as to consider the cost of different generation sources with the corresponding expansion cost of the transmission system and its actual period of construction, considering all of its construction difficulties. Here are submitted some proposals for joint bidding of generation and transmission in order to avoid the mismatch in those facilities operation starting date. [ABSTRACT FROM AUTHOR]