The Tucuruí hydro plant, which boasts the largest spillway in the world, is set to become the biggest hydro power plant in Brazil when the second stage of the project is completed. Eric Stefani gives an update on the project’s progress and the role of those involved

Tucuruí is located on the Tocantins river in Brazil, 350km south of Belém. The hydroelectricity the plant generates is used in Tucuruí City in the state of Pará, about 300km from Belém, and 270km from Marabá. The Tucuruí site was chosen from the results obtained in a systematic inventory of the energy potential of the Tocantins river and its tributaries.

The energy potential of the Tocantins-Araguaia system is being used for several projects; some have already been built and some are still under construction, of which Tucuruí is the last to be developed.

First stage

Tucuruí’s first stage has been in operation since November 1984 and has 12 x 330MW generating units, 2 x 25MW auxiliary units and a spillway with 23 floodgates. The first stage of Tucuruí alone makes it the fourth largest hydro power plant in Brazil, boasting the biggest spillway in the world.

An important transmission system is associated with the first stage, and belongs to North System-Northeast, for electricity supply to the states of Pará, Maranhão and the north of Goiás. The system also allows an exchange of power with the northeastern area of Brazil and through linked transmission systems.

Tucuruí’s transmission system, called ‘Subsistema Norte’, is composed of 2930km of 500kV transmission lines, 630km of 230kV lines and 11 substations which are linked to the sub transmission system and regional distribution.

Second stage

Tucuruí’s second stage, whose contracts were signed in February 2000, will add another 11 x 370MW generating units to the plant. To accommodate the second stage a major upgrade of the already extensive transmission system is being undertaken.

Tucuruí’s 13a generating unit is scheduled to start operating in May 2003. From this date a new generating unit will start operating every four months, until all 23 generating units are in operation. Once the second stage of the works has been completed, Tucuruí will have a total installed capacity of approximately 8400MW. Tucuruí will become the largest Brazilian hydroelectric power station, accomplished with 100% of national resources.

The second stage of the project is designed to have minimal additional environmental impact. The new power house is being constructed alongside the stage I power house and the intention is to add the extra generating capacity without increasing the size of the reservoir. The reservoir formed by the Tucuruí dam has an approximate volume of 45.8B m3, flooding an area of 2430km2.

The consortium

During the construction of the first stage, alstom led the consortium of equipment suppliers and was responsible for the supply of 12 vertical Francis turbines, six generators, a bus bar for eight generating units and a supervision system.

For the second stage of the project, Alstom is the general co-ordinator of the Consórcio Empresarial Tucuruí (CETUC ) and is responsible for the project, production, supply, assembly and commissioning of the main equipment. ge-hydro, Inepar-Fem and Constructor Norberto Odebrecht are also part of the consortium.

GE Hydro is supplying three turbines and three generators with a total value of about US$65M. Inepar-Fem is supplying a range of major equipment including floodgates to a value of US$30M, while Odebrecht’s role will cover assembly at a cost of around US$66M. The value of the entire contract is approximately US$420M.

Alstom will be producing, supplying and commissioning 11 vertical Francis turbines, eight generators, armoured buses for all units and protection systems for the second stage of the project. The company will also be supervising and controlling the new units and will be responsible for the retrofit of protection systems. Supervision and control of the 12 generating units of the first stage will also fall under Alstom’s responsibilities. The total value of the Alstom contract is estimated at about US$250M.