The Energy Platform was updated this year with four plants that won the latest auctions. All of them use water to cool the system.
Through the Platform, it is possible to observe that three of the plants added in this update are in places where the Quantitative Water Balance. Therefore, the capacity of water bodies is already worrying, critical or very critical.
Energy and Environment
The Energy Platform is an initiative of the Institute of Energy and Environment (IEMA) with the aim of systematizing and integrating information on thermoelectric plants (UTEs) that generate electricity in Brazil.
“The Power Plant Platform allows us to visualize how the UTEs are distributed across the territory and observe regions in which the impacts of the plants can accumulate, generating potentially significant risks,” says Vinicius de Sousa, from IEMA.
Through it, it is possible to locate each of the plants on the map along with information containing technical details of each project, water usage indicators and annual electricity generation.
This type of monitoring will become increasingly essential, as thermoelectricity is gaining greater importance in the electricity sector. This can be seen by analyzing the contracting of plants in the latest generation auctions in which new UTEs participated.
Since December 2017, 56% of the energy contracted in auctions has come from natural gas-fired thermoelectric plants. Hydroelectric plants, on the other hand, accounted for less than 2%. This may indicate that, in the coming years, gas-fired thermoelectric plants should replace hydroelectricity as the main source of expansion of the country's electricity supply.
Combined cycle natural gas
In this scenario, it is essential that the assessment of the cumulative socio-environmental impacts of these plants be adequately considered in their location planning. The four recently added plants use natural gas as fuel in a combined cycle, which uses the heat from the output of the first turbine to produce more energy, and have a wet tower as a cooling system.
The platform also presents a diagram explaining how thermoelectric conversion and cooling work, which can be done using water or air. Understanding these systems is important to determine how much water the plants will consume, which directly impacts the availability of the resource on site.
According to the United Nations (UN), a person should have access to 20 liters of water per day. For example, using the information available on the Energy Platform, it is possible to estimate that the Marlim Azul Thermal Power Plant will consume approximately 78 liters of water per second (L/s). The municipality of Macaé, where this plant is located, is already home to two other thermoelectric plants that together consume approximately 150 L/s.
Thus, with the operation of the new plant, thermoelectricity in the municipality will be responsible for almost 230 L/s, which is equivalent to 55% of all the water consumed in Macaé, according to data from the National Water Agency (ANA).
Although the region has a water balance (capacity of local water bodies) that is considered comfortable, it is important to consider whether allocating such a significant portion of its water resources to thermoelectric plants makes sense for the municipality, considering the existence of other uses that may be a priority.