The Tucuruí transmission line () is a hydroelectric power line that leads north from the Tucuruí Dam in Pará, Brazil and crosses the Amazon River. From there the eastern branch leads to Macapá in Amapá and the western branch leads to Manaus in Amazonas. The towers supporting the span across the Amazon River are nearly as high as the Eiffel Tower. Work to extend the line from Manaus north to Boa Vista, Roraima, is due to complete in 2018. There were delays in issuing the environmental permits and then legal challenges since the line crosses the territory of indigenous people who had not been consulted. Although efforts have been made to avoid environmental damage, there has been controversy about the impact of construction and of the tower maintenance corridor.
Background
Until recently the areas of Brazil north of the Amazon, including all of the states of Amapá and Roraima, and parts of the states of Pará and Amazonas, were not connected to the Brazilian national electrical power grid. These areas mainly depended on subsidised thermal power generation. The Balbina Dam fails to provide more than 20% of Manaus's electricity. The Linhão de Tucuruí, or the Tucuruí-Macapá-Manaus Interconnection, was built to link the northern communities to the grid to meet growth in power demand, particularly in the Manaus region. Hydroelectric power from the grid could replace most of the expensive and polluting power generation from oil and gas. The project would provide cheaper, cleaner, and more reliable electricity and would eliminate the expensive subsidy for thermal generation.
Technical
The project involved construction of seven double-circuit power lines with a total length of about connecting eight substations. Seven of the substations were built from scratch. The grid uses 3,600 transmission towers, with an average span of between towers. The Amazon River span is .
The project built a double circuit with a voltage of 500 kV between the Tucuruí hydroelectric plant, the second largest in the country, and the Manaus region. It runs through intermediate substations in the municipalities of Anapu, Almeirim, Oriximiná and Silves. A line connecting Amapá to the national grid, a double circuit of 230 kV, runs from the Jurupari substation in Almeirim to substations in Laranjal do Jari and Macapá. The Tucuruí Hydroelectric Dam has an installed capacity of 8,370 MW. The total transport capacity of the high tension lines is 2,400 MW.
Optical fiber cable was run along the transmission lines for use in broadband internet and telephony. The optical network with multiple 100 gigabit per second carriers was installed by TIM Brasil, designed with 17 optical spans. The spans were as long as possible due to the cost and difficulty of maintenance of regeneration sites.
Construction
The project was divided into three construction, operation and maintenance segments. The Spanish company Isolux Corsán won the concessions for lots A and B, and a consortium of Eletronorte, Abengoa and Chesf won lot C. A company was formed for each concession. The lot A section from Tucuruí to Jurupari operated by LXTE is long. The lot B section operated by LMTE from Oriximiná via Jurupari to Macapá is long. The lot C section from Oriximiná to Manaus operated by MTE (Manaus Transmissora de Energia) is long. The estimated cost was about R$3 billion. The project was financed by the Banco de la Amazonía.
Due to the environmental importance of the Amazon region the project had to minimise impact. For this reason the transmission lines mainly run beside existing highways. In many sections unusually high towers had to be built to carry the lines above treetops to avoid cuts. The Isolux Corsán part of the project involved 4,000 workers living in fourteen camps. It included a section of swamp. In the Alagados region between the Xingu and Amazon rivers the land is flooded in the rainy season and has deep mud in the "dry" season. Use of large barges proved impossible without causing unacceptable environmental damage. The solution was to use specially-built light barges propelled by a hydraulic excavator. The excavator, placed at the front of the barge, would pull it forward using its scoop. Buffalo trails showed where the deepest channels were.