Teles Pires HPP: A new frontier in energy generation in Brazil

On the westernmost extremes of Brazil’s state of Mato Grosso - in a very isolated region - the first of three hydropower plants that are scheduled to be built on the ‘Teles Pires’ River Basin is born.

Over the past ten years, Brazil has advanced in the construction of hydropower plants (HPPs); redirecting the development of this type of venture that was previously focused on the country’s South, Southeast and Center-West regions. The works for construction of the Santo Antônio and Jirau power plants in the state of Rondônia, the Belo Monte hydropower plant in Pará, and the Teles Pires hydropower plant in the far west of Mato Grosso state make it clear that Brazil will not renounce exploiting its hydrologic potential even in remote regions of the country since these are the regions with good potential for the construction of hydroelectric plants due to their geographic isolation and the low density of their populations. Other power plants are under study. On the Teles Pires River, for example, two more plants are scheduled for construction - one in the city of Sinop and another in São Manoel. In western Pará, studies proceed for the power plants of the ‘Complexo Tapajós’ (Tapajós River Hydroelectric Complex).

If, on the one hand, these initiatives have to cope with restrictions imposed by environmental licensing requirements, these difficulties wind up leading to improvements in the projects and in the systems of construction adopted in the performance of these works. The implementation of these projects is viewed as an opportunity for economic development of these regions which are markedly typified by extractive activities, such as prospecting and mining, and which are now giving way to pastures for grazing of cattle and soybean farming - as is true of the region of Alta Floresta where the Teles Pires HPP is being built.

Grandes Construções magazine visited Teles Pires in August. To get there, our staff had to cross (or ‘overcome’) the segment of highway MT 206 - at times consisting of beaten earth, at other times of segments undergoing roadwork and, in general, deprived of any signage or lighting. The amount of traffic is amazing, including trucks - many of which are loaded with logs and tree trunks. Along the road, until you get to the site of the power plant, there are huge empty spaces that were previously occupied by forests and that now consist of scorched tree stumps - almost an apocalyptic scenario - which little by little start to smell of pastures indicating the great changes that have taken place in the local landscape and in the region’s economy as well.

In the city of Alta Floresta, whose past was marked by the wealth provided by the region’s gold, cattle farming is now the primary source of money. The region is full of meat packers and is undergoing a new cycle of economic development based on the breeding of livestock and agriculture. Because of this, and also due to the flow generated by the Teles Pires project, the city’s small airport is hard pressed to handle the huge number of visitors who come and go every day. Ecotourism, based on sport fishing, attracts foreign tourists and demonstrates how Brazil does not know how to capitalize on its tourist potential based on its natural resources. But the inhabitants of the region’s smaller towns, such as Paranaíta, suffer from their great distance from any type of public service or facilities and dream of the benefits that are to come with the introduction of the Teles Pires HPP.

Lower Price

The ‘Estudos de Inventário da Bacia Hidrográfica do Rio Teles Pires’ (Inventory Studies of the Teles Pires River Basin) approved by Brazil’s energy authority Aneel, indicated, in July 2006, the potential for the construction of a series of six hydropower plants totaling a generating capacity of 3,600 megawatts (MW) in the Basin in which the Teles Pires HPP - with an installed capacity of 1,820 MW -  accounts for 50.55%.

The Teles Pires HPP concession was purchased at the last auction for power generation in 2010 by the Consortium Teles Pires Energia Eficiente which proposed a discount of 33% compared to the ‘ceiling rate’ for electrical energy; in other words, the bid presented by the consortium was the lowest price per kWh to produce or generate electricity, and was considered to be the lowest rate that the Federal Government had succeeded in securing through the auctions of power plants. This will enable a lower rate for electrical energy. The project is included in the government’s ‘Progama de Aceleração do Crescimento’ (PAC - Program for Acceleration of Growth) and the investment totals R$ 4 billion (US$ 1.82 Bn); half of that applied in the construction works. After the auction, the ‘Companhia Hidrelétrica Teles Pires S/A’ - a Special Purpose Entity (SPE) - was created and is responsible for building and operating the Teles Pires HPP. The partners in the SPE are Neoenergia (50.1%), Eletrobras-Eletrosul (24.5%), Eletrobras-Furnas (24.5%) and Odebrecht Energia (0.9%).

The Teles Pires HPP improved upon the original engineering project, proposing the installation of just five turbines (of 364 MW each) while maintaining the same installed power of 1,820 MW - in the initial project that was approved at the auction, six turbines had been foreseen. Another innovation was the reduction in the volume of services compared to the original position of the HPP (for instance, a reduction in the volume of excavation) thus enabling a new project timetable set for 38 months for the beginning of power generation.

The company proposed a new model of distribution of workers throughout the implementation of the project, seeking to improve rationalization in the occupation of areas so as to avoid the concentration of personnel at a single core area thereby facilitating access by workers to support facilities and services, as well as the cafeteria and accommodations. At the same time, consideration was given to the distribution of direct jobs throughout the project, reducing their concentration at the peak of work and the decision to hire 45% of the workers in the region in addition to the implementation of the ‘Programa de Qualificação Profissional Continuada – Acreditar’ - a continuing program for professional qualification developed by the Odebrecht construction company. Keeping all the workers housed in accommodations at the construction site was also an initiative that reinforced the distinctiveness of the project.

The Teles Pires Construction Consortium was engaged under an Engineering, Procurement and Construction (EPC) agreement in which the consortium is responsible for the design and civil works, supply and installation of electromechanical equipment for the venture. This consortium consists of the following companies: Odebrecht, Voith, Alstom, PCE and Intertechne.

The plant is the first to be built in the Teles Pires Complex which includes two other projects that have already been confirmed: the Sinop HPP with 461 MW of capacity and the São Manoel, HPP with 700 MW. The Sinop HPP was listed in the A-5 auction held by the government in December of last year, but it did not receive any bids and should be offered again at the next call for bidding. The São Manoel HPP has not yet been scheduled for the auction sponsored by the federal government’s ‘Empresa de Pesquisa Energética’ (EPE - Energy Research Company). Together, the three HPPs will be able to generate close to 3,000 MW in the ‘Sistema Interligado Nacional’ (SIN -National Interconnected System), reinforcing the country's energy security. Teles Pires will be the largest hydroelectric power plant in Mato Grosso - a state which is presently served essentially by small and medium-sized HPPs generating from 30 MW - from Small Hydropower Plants (SHPPs) - to 200 MW.

Distinctive design

The project is located at coordinates LONG 56°46'35" W and LAT 09°20'35" S on the Teles Pires River, 330 km from its junction with the Juruena River where the two rivers form the Tapajós River. The dam is located on the border of the states of Mato Grosso (MT) and Pará (PA) at the municipalities of Paranaíta - MT and Jacareacanga - PA. The project is located 945 km by land from the city of Cuiabá - capital of the state of Mato Grosso - and 85 km from Paranaíta; the city closest to the project.

The dam in the bed of the Teles Pires River will be built with blocks of rock and have a clay core and the predominant part will be made of Roller-Compacted Concrete (RCC). The top of the dam will reach a height of 224 meters. The spillway will be equipped with five gates and have 10 louvers which will drain the water ensuring that the excess is discharged safely downstream. The job site has been installed near the dam’s axis, on the left bank, and will have various facilities such as: sentinel, substation, workshop, inventory warehouse, fuel storage, carpentry, rebar tying patio, patio electromechanical patio, mechanical assembly area, laboratories, storage rooms, offices, cafeteria and nursing/first-aid station. The job-site camp was established on the left bank, about eight kilometers from the industrial yard and houses all the equipment necessary for use by the workers. Facilities include water and sewage-treatment stations, lodging, laundry, cafeterias, leisure centers and first-aid stations.

The reservoir will occupy areas of both municipalities close to the project - in Pará, 16% of the municipality of Jacareacanga; and in Mato Grosso, 84% of the municipality of Paranaíta. The lake formed by the dam will be about 70 km long, along the Teles Pires River, and occupy an area of 150 km² with a water surface of 135.6 km² and a flooded area of 95.0 km², equivalent to 0.052 km² of flooded area per megawatt generated. Work to rescue fauna and flora are at an advanced stage to allow the establishment of the reservoir.

The powerhouse is located on the right bank of the Teles Pires River and of the conventional closed-type, housing the five generator units. The substation, in turn, will be located on the left bank, about 200 meters away from the tailrace of the powerhouse. All the energy generated by Teles Pires HPP will be transmitted via a 7.5 km long restricted use transmission line which will connect to the ‘Coletora Norte’ Substation (SE Coletora Norte). The connection to the ‘Sistema Interligado Nacional’ (SIN - National Interconnected Power System) will be via a 500 KV transmission line which will have its point of connection to the SIN at the ‘Ribeirãozinho’ Substation (SE Ribeirãozinho) in Mato Grosso, on the border of the state of Goiás.

Diversion concluded

The project has completed the first milestone in its construction: the diversion of the Teles Pires River. The process was completed on June 6th with the excavation of three tunnels on the left bank, each measuring 318 meters long, 15 meters wide and 16 meters high. Having concluded this step, work could begin on the riverbed for the construction of the main dam.

Thus, it was possible to start the construction of generating circuit (where the generator that will produce energy is located) and electromechanical assembly. According to contract director Antonio Augusto Castro Santos, the time frame is the main challenge of the project. “There is no record of a job the size of Teles Pires getting done in a time frame that we have here - 38 months. Our forecast is to start generating with the first generating unit as early as next year.” He reminds us that the project actually began to be implemented in January 2011 with the elaboration of the environmental projects and the application for the installation permit. “We’re celebrating two years of work, in addition to eight months for the initial phase, which have been mobilized with the engineering team and planning,” he recalls.

To the engineer, Teles Pires is one of the best hydropower projects ever made in the country due to its location. “There are only about 30 families being affected, with most of the residences consisting of homes for vacationing,” he points out. The hydropower plant is a ‘run-of-the-river’ type with a reservoir of limited size. However, since the river has a very constant and predictable volume of water, and a hydrological regime that is similar year in and year out, this regularity enhances the capacity of the plant. “This allows a very high generation of energy, combined with being a region of low or non-existent impact on populations around the Teles Pires lake,” he points out.

The engineer points out that this HPP pioneers the exploration of a river that is practically isolated in the Amazon region. This fact means that housing was required for almost 100% of the workers at the construction site; a unique condition in comparison to other similar works, such as Santo Antonio, Jirau and Belo Monte which were near urban centers. “These circumstances were very well pondered over the six or seven years of studies that were carried out until the project’s execution,” he says. As one of the first works to enter the Amazon region, the hydropower plant also serves as a laboratory for information on both technical and environment aspects to assist in the construction of the other proposed HPPs along the Teles Pires and Tapajós Rivers. According to him, the Sinop hydropower plant, which is yet to be put up for auction, will have good-sized reservoir that should afford greater regularity of conditions for the Teles Pires HPP.

One project, many challenges

“I think the big challenge for Teles Pires was actually overcoming this isolation,” says the contract director. “It is an HPP of very large dimensions. The equipment for generation at Teles Pires is almost as big what you find in the plants of Itaipu, Tucuruí, and Belo Monte, only its in an isolated region. We're about 3,500 kilometers from the site where this equipment is manufactured. It is a very big challenge to think and execute this project under these conditions. And, especially, keep people motivated to stay here,” he underscores.

To achieve this, a few solutions were adopted to reduce the labor force and other measures were established to ensure that the job site was kept orderly and motivated at the same time. To reduce the number of workers, originally planned to be 7000, we decided to use large equipment capable of withstanding high workloads, virtually without interruption.

“US$ 180 million were invested in new equipment to handle the works.” The investment includes systems for cutting and bending of steel, differentiated formwork and earthmoving equipment of a greater size and operational capacity. Among the machines used are high performance cranes, concrete batching plants, plants for crushing of rock and cooling of concrete with cold water and an ice-making center, besides several earthmoving machines, “all new and some large,” he points out. He mentions the 70 ton excavators and leading-edge off-road trucks with satellite monitoring. “The priority was to maximize productivity while proving assurance that the work would be executed within the prescribed period.” Outstanding among the machines used are Volvo excavators, CAT D8 bulldozers and Scania dump trucks.

The use of formwork represented a further gain for the works, says the engineer, citing Ulma-brand slip forms. “The use of formwork makes the process more industrial and less artisanal. The formwork made by Ulma is replacing a system that was previously used which was almost a work of art due to the number of steps involved. When one opts for an industrialized system, which arrives at the job site ready for use, one eliminates a phase of assembly and consequently the demand for skilled labor. This maximizes production,” he says.