After the changes in Brazilian legislation in the 1990s private companies began to be able to invest in power generation consortiums at very competitive costs. This measure contributed not only to business expanding, but also to its sustainability.

Energy is fundamental for producing aluminum because it makes it possible to transform bauxite into alumina. Alcoa, through its participation in consortiums like Barra Grande and Machadinho, both located on the border of Rio Grande do Sul with Santa Catarina, guarantees that Company operations are 38% self-sufficient in terms of energy.

The Poços de Caldas unit is an example of energy self-sufficiency. Alcoa’s contract with Companhia Eletronorte, which operates in the Amazon region, guarantees supplies for Alumar until 2024. 

The Company also has shareholdings in the hydroelectric power consortiums of Estreito, on the border between Tocantins and Maranhão, and Serra do Facão, between Goiás and Minas Gerais, both of which are currently under construction. These investments have already cost a total of US$ 1.1 billion. 

- Where to build a hydroelectric power station?
The definition of where a hydroelectric power station will be built results from the inventory, feasibility and basic project studies, which are carried out in line with current legislation, including environmental legislation. Technical factors are also taken into consideration, such as:

• The compatibility of the water outflow; 
• The height the water drops; 
• The acceptability of the topographical and geological conditions; 
• The availability of construction materials; 
• A pre-defined energy consumer market; 
• Infrastructure introduction studies. 

After checking all these items, if the cost/benefit ratio is favorable the process goes ahead.

- How is energy generated?
To generate energy, the water initially passes along a channel called an adduction channel (*1). From there it is conducted along an intake channel and penstocks to turn the blades of the turbine, which is coupled to the rotor that generates electrical power and which are installed in the powerhouse.

In the powerhouse, which is located at a lower level than the intake channel (around 80 m), the power transformation is processed.

After passing through the turbine the water is conducted along a structure called a suction tube (*2) and a discharge channel (*3), and once more returns to the natural river bed.

The electricity produced is transformed and conducted via a reinforced substation (SF6) (*4) to the transmission system (*5).

• 1: For channeling the water to the intake channel
• 2: Structure, lower than the powerhouse, along which the water runs after passing through the turbine and being sent to the discharge channel
• 3: For returning the water to the natural bed of the river after passing through the turbines
• 4: The reinforced SF (sulphur hexafluoride) gas insulated substation consists of measuring and protection equipment, enclosed in metal jackets, the objective of which is to allow the energy coming from the generators to flow into the transmission system
• 5: Consisting of transmission lines and substations, the transmission system transmits the power generated at the power station to the consumer centers, where it is distributed.