Energy production by thermoelectric plants grows 77% in 2021, study shows

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Brazil increased its energy generation through fossil thermoelectric plants by 77% between 2020 and 2021, according to a study released this Thursday (30) by the Energy and Environment Institute (Iema).

The data were published in the Inventory of Atmospheric Emissions in Thermoelectric Power Plants, a document that analyzes the performance of the public service units that make up the National Interconnected System (SIN), responsible for supplying much of the country.

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In 2020, the 72 fossil thermoelectric plants connected to the SIN produced 54.1 Terawatt-hours (TWh) of electricity. The following year, the number reached 96 TWh. According to Iema, the number of plants in 2021 grew, but the institute does not have accurate data on this increase.

The energy generated in these units rose 177% between 2000 and 2020. The number jumped from 30.6 TWh to 84.8 TWh in this period.

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In the national energy matrix, the share of fossil sources rose from 9% in 2000 to 14% in 2020. For researcher Felipe Barcellos, from Iema, growth is mainly due to two factors: increased demand for energy, which was not matched by the supply, and the repeated water crises in the country.

“The increase in the use of these fuels is more structural than the water crisis last year, for example. This increase has been happening consistently for several years. This is because the Brazilian territory no longer has enough space to accommodate new hydroelectric plants, which account for most of the energy generated. The only areas available are mainly in the Amazon, and the installation of these projects also brings several environmental problems”, says the researcher.

The Iema study points out that, in the last two decades, the total generation of electric energy in the country grew 78%, while the generation through hydraulic sources increased only 30%. Also according to the institute, since the beginning of the 2000s, there has been a growing diversification of sources to meet the evolution of national demand.

This diversification is mainly marked by the increased participation of non-hydro renewable sources, such as biomass and wind, and by the expansion of the use of fossil fuels.

Increase in the emission of greenhouse gases

The growth in the use of fossil fuels goes against the country’s goals of reducing greenhouse gas emissions. In 2021, energy production from these sources was responsible for the emission of the equivalent of 58 million tons of CO². The number is 78% higher than in 2020, when 32.7 million tons of CO² were emitted.

According to researcher Felipe Barcellos, it is necessary to plan the replacement of this type of plant with clean alternatives, otherwise the change may become unfeasible.

“As these are large undertakings, it cannot be done overnight, but if we do not think about it in a structural way, the change will not be viable. So the important thing is to realize that we are in the opposite direction, increasing rather than decreasing the emission of greenhouse gases, and start planning how to make this conversion of the energy matrix”, says Barcellos.

“We at the institute know that this transition also needs to be fair, we can’t just close plants. We have to think about the people who work in these places and the economic importance that this energy has today. But in general, from an environmental and even an economic point of view, the use of these fuels is less advantageous. The Northeast, for example, which does not have coal and uses other energy sources, gives us the impression that these sources are not completely necessary and can indeed be replaced”, evaluates the researcher.

Other environmental impacts

According to Iema, in addition to greenhouse gas emissions, this generation category results in a series of other environmental problems, such as local atmospheric pollution and water stress, due to the use of water for cooling systems.

Researcher Felipe Barcellos suggests that this type of environmental impact should be taken into account when licensing fossil plants.

“The bidding criteria include the price, in reais per megawatt hour, technical feasibility, for example, but greenhouse gas emissions, pollutants, and the use of water for internal cooling could also be included. Many plants use fresh water from a nearby river and then this water evaporates and does not necessarily return to the same basin, which can generate water stress. So it is necessary to think in a systemic way, in the place where the plant is being installed, and not only in the characteristics of the establishments”, says the researcher.

Mineral coal and natural gas

In the last 20 years, the fuel that showed the greatest growth among fossil energy sources was natural gas, which went from a percentage of 8% in 2000 to 71% in 2020. Mineral coal, on the other hand, went from 39% to 19% in that same period.

Researcher Felipe Barcellos points out that, despite the drop in the share of fossil fuels, the use of coal has increased in absolute terms. According to him, power generation through coal rose from 7 TWh in 2000 to 11 TWh in 2020.

According to him, in comparison with coal, natural gas generates fewer greenhouse gases, but still needs to be replaced by cleaner sources.

Each gas has an emission factor, which is the amount of gases it generates when producing 1 unit of energy. So natural gas emits 56 tons of CO² per 1 unit of energy. Coal, on the other hand, emits around 100 tons of CO² per 1 unit of energy. In other words, it’s almost double”, he explains.

Data presented by the researcher indicate that coal is responsible for 35% of CO² emissions and among fossil fuels. Natural gas accounts for 59% of emissions.

Challenges and alternatives

Also according to the specialist, one of the factors that can make the energy transition difficult is the fact that the licensing contracts for thermoelectric plants provide for many years of operation, with the aim of making investments viable.

He explains that technological advances from other sources, such as solar and wind, happen at high speed, but still have limitations in terms of storage capacity.

“Solar energy batteries, for example, still do not have the capacity to store a large amount of energy, so this source is very dependent on weather conditions. So, like wind power, which depends on the amount of wind”, explains the researcher.

According to him, a solution to the limitation is the so-called green hydrogen. With the energy generated by the wind, for example, it is possible to produce hydrogen and, when there is no more wind, it is possible to generate energy again, only from hydrogen. According to the researcher, the technology is still under development.

Source: CNN Brasil

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